| 1 | use crate::alloc::alloc::{handle_alloc_error, Layout}; | 
| 2 | use crate::control::{BitMaskIter, Group, Tag, TagSliceExt}; | 
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| 3 | use crate::scopeguard::{guard, ScopeGuard}; | 
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| 4 | use crate::util::{invalid_mut, likely, unlikely}; | 
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| 5 | use crate::TryReserveError; | 
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| 6 | use core::array; | 
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| 7 | use core::iter::FusedIterator; | 
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| 8 | use core::marker::PhantomData; | 
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| 9 | use core::mem; | 
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| 10 | use core::ptr::NonNull; | 
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| 11 | use core::slice; | 
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| 12 | use core::{hint, ptr}; | 
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| 13 |  | 
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| 14 | mod alloc; | 
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| 15 | #[ cfg(test)] | 
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| 16 | pub(crate) use self::alloc::AllocError; | 
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| 17 | pub(crate) use self::alloc::{do_alloc, Allocator, Global}; | 
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| 18 |  | 
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| 19 | #[ inline] | 
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| 20 | unsafe fn offset_from<T>(to: *const T, from: *const T) -> usize { | 
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| 21 | to.offset_from(origin:from) as usize | 
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| 22 | } | 
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| 23 |  | 
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| 24 | /// Whether memory allocation errors should return an error or abort. | 
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| 25 | #[ derive(Copy, Clone)] | 
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| 26 | enum Fallibility { | 
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| 27 | Fallible, | 
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| 28 | Infallible, | 
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| 29 | } | 
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| 30 |  | 
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| 31 | impl Fallibility { | 
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| 32 | /// Error to return on capacity overflow. | 
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| 33 | #[ cfg_attr(feature = "inline-more", inline)] | 
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| 34 | fn capacity_overflow(self) -> TryReserveError { | 
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| 35 | match self { | 
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| 36 | Fallibility::Fallible => TryReserveError::CapacityOverflow, | 
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| 37 | Fallibility::Infallible => panic!( "Hash table capacity overflow"), | 
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| 38 | } | 
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| 39 | } | 
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| 40 |  | 
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| 41 | /// Error to return on allocation error. | 
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| 42 | #[ cfg_attr(feature = "inline-more", inline)] | 
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| 43 | fn alloc_err(self, layout: Layout) -> TryReserveError { | 
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| 44 | match self { | 
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| 45 | Fallibility::Fallible => TryReserveError::AllocError { layout }, | 
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| 46 | Fallibility::Infallible => handle_alloc_error(layout), | 
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| 47 | } | 
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| 48 | } | 
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| 49 | } | 
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| 50 |  | 
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| 51 | trait SizedTypeProperties: Sized { | 
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| 52 | const IS_ZERO_SIZED: bool = mem::size_of::<Self>() == 0; | 
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| 53 | const NEEDS_DROP: bool = mem::needs_drop::<Self>(); | 
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| 54 | } | 
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| 55 |  | 
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| 56 | impl<T> SizedTypeProperties for T {} | 
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| 57 |  | 
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| 58 | /// Primary hash function, used to select the initial bucket to probe from. | 
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| 59 | #[ inline] | 
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| 60 | #[ allow(clippy::cast_possible_truncation)] | 
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| 61 | fn h1(hash: u64) -> usize { | 
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| 62 | // On 32-bit platforms we simply ignore the higher hash bits. | 
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| 63 | hash as usize | 
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| 64 | } | 
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| 65 |  | 
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| 66 | /// Probe sequence based on triangular numbers, which is guaranteed (since our | 
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| 67 | /// table size is a power of two) to visit every group of elements exactly once. | 
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| 68 | /// | 
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| 69 | /// A triangular probe has us jump by 1 more group every time. So first we | 
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| 70 | /// jump by 1 group (meaning we just continue our linear scan), then 2 groups | 
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| 71 | /// (skipping over 1 group), then 3 groups (skipping over 2 groups), and so on. | 
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| 72 | /// | 
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| 73 | /// Proof that the probe will visit every group in the table: | 
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| 74 | /// <https://fgiesen.wordpress.com/2015/02/22/triangular-numbers-mod-2n/> | 
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| 75 | #[ derive(Clone)] | 
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| 76 | struct ProbeSeq { | 
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| 77 | pos: usize, | 
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| 78 | stride: usize, | 
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| 79 | } | 
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| 80 |  | 
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| 81 | impl ProbeSeq { | 
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| 82 | #[ inline] | 
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| 83 | fn move_next(&mut self, bucket_mask: usize) { | 
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| 84 | // We should have found an empty bucket by now and ended the probe. | 
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| 85 | debug_assert!( | 
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| 86 | self.stride <= bucket_mask, | 
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| 87 | "Went past end of probe sequence" | 
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| 88 | ); | 
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| 89 |  | 
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| 90 | self.stride += Group::WIDTH; | 
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| 91 | self.pos += self.stride; | 
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| 92 | self.pos &= bucket_mask; | 
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| 93 | } | 
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| 94 | } | 
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| 95 |  | 
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| 96 | /// Returns the number of buckets needed to hold the given number of items, | 
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| 97 | /// taking the maximum load factor into account. | 
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| 98 | /// | 
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| 99 | /// Returns `None` if an overflow occurs. | 
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| 100 | // Workaround for emscripten bug emscripten-core/emscripten-fastcomp#258 | 
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| 101 | #[ cfg_attr(target_os = "emscripten", inline(never))] | 
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| 102 | #[ cfg_attr(not(target_os = "emscripten"), inline)] | 
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| 103 | fn capacity_to_buckets(cap: usize, table_layout: TableLayout) -> Option<usize> { | 
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| 104 | debug_assert_ne!(cap, 0); | 
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| 105 |  | 
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| 106 | // For small tables we require at least 1 empty bucket so that lookups are | 
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| 107 | // guaranteed to terminate if an element doesn't exist in the table. | 
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| 108 | if cap < 15 { | 
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| 109 | // Consider a small TableLayout like { size: 1, ctrl_align: 16 } on a | 
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| 110 | // platform with Group::WIDTH of 16 (like x86_64 with SSE2). For small | 
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| 111 | // bucket sizes, this ends up wasting quite a few bytes just to pad to | 
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| 112 | // the relatively larger ctrl_align: | 
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| 113 | // | 
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| 114 | // | capacity | buckets | bytes allocated | bytes per item | | 
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| 115 | // | -------- | ------- | --------------- | -------------- | | 
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| 116 | // |        3 |       4 |              36 | (Yikes!)  12.0 | | 
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| 117 | // |        7 |       8 |              40 | (Poor)     5.7 | | 
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| 118 | // |       14 |      16 |              48 |            3.4 | | 
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| 119 | // |       28 |      32 |              80 |            3.3 | | 
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| 120 | // | 
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| 121 | // In general, buckets * table_layout.size >= table_layout.ctrl_align | 
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| 122 | // must be true to avoid these edges. This is implemented by adjusting | 
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| 123 | // the minimum capacity upwards for small items. This code only needs | 
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| 124 | // to handle ctrl_align which are less than or equal to Group::WIDTH, | 
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| 125 | // because valid layout sizes are always a multiple of the alignment, | 
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| 126 | // so anything with alignment over the Group::WIDTH won't hit this edge | 
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| 127 | // case. | 
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| 128 |  | 
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| 129 | // This is brittle, e.g. if we ever add 32 byte groups, it will select | 
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| 130 | // 3 regardless of the table_layout.size. | 
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| 131 | let min_cap = match (Group::WIDTH, table_layout.size) { | 
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| 132 | (16, 0..=1) => 14, | 
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| 133 | (16, 2..=3) => 7, | 
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| 134 | (8, 0..=1) => 7, | 
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| 135 | _ => 3, | 
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| 136 | }; | 
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| 137 | let cap = min_cap.max(cap); | 
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| 138 | // We don't bother with a table size of 2 buckets since that can only | 
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| 139 | // hold a single element. Instead, we skip directly to a 4 bucket table | 
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| 140 | // which can hold 3 elements. | 
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| 141 | return Some(if cap < 4 { | 
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| 142 | 4 | 
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| 143 | } else if cap < 8 { | 
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| 144 | 8 | 
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| 145 | } else { | 
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| 146 | 16 | 
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| 147 | }); | 
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| 148 | } | 
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| 149 |  | 
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| 150 | // Otherwise require 1/8 buckets to be empty (87.5% load) | 
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| 151 | // | 
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| 152 | // Be careful when modifying this, calculate_layout relies on the | 
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| 153 | // overflow check here. | 
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| 154 | let adjusted_cap = cap.checked_mul(8)? / 7; | 
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| 155 |  | 
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| 156 | // Any overflows will have been caught by the checked_mul. Also, any | 
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| 157 | // rounding errors from the division above will be cleaned up by | 
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| 158 | // next_power_of_two (which can't overflow because of the previous division). | 
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| 159 | Some(adjusted_cap.next_power_of_two()) | 
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| 160 | } | 
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| 161 |  | 
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| 162 | /// Returns the maximum effective capacity for the given bucket mask, taking | 
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| 163 | /// the maximum load factor into account. | 
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| 164 | #[ inline] | 
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| 165 | fn bucket_mask_to_capacity(bucket_mask: usize) -> usize { | 
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| 166 | if bucket_mask < 8 { | 
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| 167 | // For tables with 1/2/4/8 buckets, we always reserve one empty slot. | 
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| 168 | // Keep in mind that the bucket mask is one less than the bucket count. | 
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| 169 | bucket_mask | 
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| 170 | } else { | 
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| 171 | // For larger tables we reserve 12.5% of the slots as empty. | 
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| 172 | ((bucket_mask + 1) / 8) * 7 | 
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| 173 | } | 
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| 174 | } | 
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| 175 |  | 
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| 176 | /// Helper which allows the max calculation for `ctrl_align` to be statically computed for each `T` | 
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| 177 | /// while keeping the rest of `calculate_layout_for` independent of `T` | 
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| 178 | #[ derive(Copy, Clone)] | 
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| 179 | struct TableLayout { | 
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| 180 | size: usize, | 
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| 181 | ctrl_align: usize, | 
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| 182 | } | 
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| 183 |  | 
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| 184 | impl TableLayout { | 
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| 185 | #[ inline] | 
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| 186 | const fn new<T>() -> Self { | 
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| 187 | let layout = Layout::new::<T>(); | 
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| 188 | Self { | 
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| 189 | size: layout.size(), | 
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| 190 | ctrl_align: if layout.align() > Group::WIDTH { | 
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| 191 | layout.align() | 
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| 192 | } else { | 
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| 193 | Group::WIDTH | 
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| 194 | }, | 
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| 195 | } | 
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| 196 | } | 
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| 197 |  | 
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| 198 | #[ inline] | 
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| 199 | fn calculate_layout_for(self, buckets: usize) -> Option<(Layout, usize)> { | 
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| 200 | debug_assert!(buckets.is_power_of_two()); | 
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| 201 |  | 
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| 202 | let TableLayout { size, ctrl_align } = self; | 
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| 203 | // Manual layout calculation since Layout methods are not yet stable. | 
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| 204 | let ctrl_offset = | 
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| 205 | size.checked_mul(buckets)?.checked_add(ctrl_align - 1)? & !(ctrl_align - 1); | 
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| 206 | let len = ctrl_offset.checked_add(buckets + Group::WIDTH)?; | 
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| 207 |  | 
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| 208 | // We need an additional check to ensure that the allocation doesn't | 
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| 209 | // exceed `isize::MAX` (https://github.com/rust-lang/rust/pull/95295). | 
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| 210 | if len > isize::MAX as usize - (ctrl_align - 1) { | 
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| 211 | return None; | 
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| 212 | } | 
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| 213 |  | 
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| 214 | Some(( | 
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| 215 | unsafe { Layout::from_size_align_unchecked(len, ctrl_align) }, | 
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| 216 | ctrl_offset, | 
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| 217 | )) | 
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| 218 | } | 
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| 219 | } | 
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| 220 |  | 
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| 221 | /// A reference to an empty bucket into which an can be inserted. | 
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| 222 | pub struct InsertSlot { | 
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| 223 | index: usize, | 
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| 224 | } | 
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| 225 |  | 
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| 226 | /// A reference to a hash table bucket containing a `T`. | 
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| 227 | /// | 
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| 228 | /// This is usually just a pointer to the element itself. However if the element | 
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| 229 | /// is a ZST, then we instead track the index of the element in the table so | 
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| 230 | /// that `erase` works properly. | 
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| 231 | pub struct Bucket<T> { | 
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| 232 | // Actually it is pointer to next element than element itself | 
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| 233 | // this is needed to maintain pointer arithmetic invariants | 
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| 234 | // keeping direct pointer to element introduces difficulty. | 
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| 235 | // Using `NonNull` for variance and niche layout | 
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| 236 | ptr: NonNull<T>, | 
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| 237 | } | 
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| 238 |  | 
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| 239 | // This Send impl is needed for rayon support. This is safe since Bucket is | 
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| 240 | // never exposed in a public API. | 
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| 241 | unsafe impl<T> Send for Bucket<T> {} | 
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| 242 |  | 
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| 243 | impl<T> Clone for Bucket<T> { | 
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| 244 | #[ inline] | 
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| 245 | fn clone(&self) -> Self { | 
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| 246 | Self { ptr: self.ptr } | 
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| 247 | } | 
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| 248 | } | 
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| 249 |  | 
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| 250 | impl<T> Bucket<T> { | 
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| 251 | /// Creates a [`Bucket`] that contain pointer to the data. | 
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| 252 | /// The pointer calculation is performed by calculating the | 
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| 253 | /// offset from given `base` pointer (convenience for | 
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| 254 | /// `base.as_ptr().sub(index)`). | 
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| 255 | /// | 
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| 256 | /// `index` is in units of `T`; e.g., an `index` of 3 represents a pointer | 
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| 257 | /// offset of `3 * size_of::<T>()` bytes. | 
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| 258 | /// | 
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| 259 | /// If the `T` is a ZST, then we instead track the index of the element | 
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| 260 | /// in the table so that `erase` works properly (return | 
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| 261 | /// `NonNull::new_unchecked((index + 1) as *mut T)`) | 
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| 262 | /// | 
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| 263 | /// # Safety | 
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| 264 | /// | 
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| 265 | /// If `mem::size_of::<T>() != 0`, then the safety rules are directly derived | 
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| 266 | /// from the safety rules for [`<*mut T>::sub`] method of `*mut T` and the safety | 
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| 267 | /// rules of [`NonNull::new_unchecked`] function. | 
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| 268 | /// | 
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| 269 | /// Thus, in order to uphold the safety contracts for the [`<*mut T>::sub`] method | 
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| 270 | /// and [`NonNull::new_unchecked`] function, as well as for the correct | 
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| 271 | /// logic of the work of this crate, the following rules are necessary and | 
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| 272 | /// sufficient: | 
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| 273 | /// | 
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| 274 | /// * the `base` pointer must not be `dangling` and must points to the | 
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| 275 | ///   end of the first `value element` from the `data part` of the table, i.e. | 
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| 276 | ///   must be the pointer that returned by [`RawTable::data_end`] or by | 
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| 277 | ///   [`RawTableInner::data_end<T>`]; | 
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| 278 | /// | 
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| 279 | /// * `index` must not be greater than `RawTableInner.bucket_mask`, i.e. | 
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| 280 | ///   `index <= RawTableInner.bucket_mask` or, in other words, `(index + 1)` | 
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| 281 | ///   must be no greater than the number returned by the function | 
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| 282 | ///   [`RawTable::buckets`] or [`RawTableInner::buckets`]. | 
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| 283 | /// | 
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| 284 | /// If `mem::size_of::<T>() == 0`, then the only requirement is that the | 
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| 285 | /// `index` must not be greater than `RawTableInner.bucket_mask`, i.e. | 
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| 286 | /// `index <= RawTableInner.bucket_mask` or, in other words, `(index + 1)` | 
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| 287 | /// must be no greater than the number returned by the function | 
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| 288 | /// [`RawTable::buckets`] or [`RawTableInner::buckets`]. | 
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| 289 | /// | 
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| 290 | /// [`Bucket`]: crate::raw::Bucket | 
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| 291 | /// [`<*mut T>::sub`]: https://doc.rust-lang.org/core/primitive.pointer.html#method.sub-1 | 
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| 292 | /// [`NonNull::new_unchecked`]: https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.new_unchecked | 
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| 293 | /// [`RawTable::data_end`]: crate::raw::RawTable::data_end | 
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| 294 | /// [`RawTableInner::data_end<T>`]: RawTableInner::data_end<T> | 
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| 295 | /// [`RawTable::buckets`]: crate::raw::RawTable::buckets | 
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| 296 | /// [`RawTableInner::buckets`]: RawTableInner::buckets | 
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| 297 | #[ inline] | 
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| 298 | unsafe fn from_base_index(base: NonNull<T>, index: usize) -> Self { | 
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| 299 | // If mem::size_of::<T>() != 0 then return a pointer to an `element` in | 
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| 300 | // the data part of the table (we start counting from "0", so that | 
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| 301 | // in the expression T[last], the "last" index actually one less than the | 
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| 302 | // "buckets" number in the table, i.e. "last = RawTableInner.bucket_mask"): | 
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| 303 | // | 
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| 304 | //                   `from_base_index(base, 1).as_ptr()` returns a pointer that | 
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| 305 | //                   points here in the data part of the table | 
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| 306 | //                   (to the start of T1) | 
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| 307 | //                        | | 
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| 308 | //                        |        `base: NonNull<T>` must point here | 
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| 309 | //                        |         (to the end of T0 or to the start of C0) | 
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| 310 | //                        v         v | 
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| 311 | // [Padding], Tlast, ..., |T1|, T0, |C0, C1, ..., Clast | 
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| 312 | //                           ^ | 
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| 313 | //                           `from_base_index(base, 1)` returns a pointer | 
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| 314 | //                           that points here in the data part of the table | 
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| 315 | //                           (to the end of T1) | 
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| 316 | // | 
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| 317 | // where: T0...Tlast - our stored data; C0...Clast - control bytes | 
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| 318 | // or metadata for data. | 
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| 319 | let ptr = if T::IS_ZERO_SIZED { | 
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| 320 | // won't overflow because index must be less than length (bucket_mask) | 
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| 321 | // and bucket_mask is guaranteed to be less than `isize::MAX` | 
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| 322 | // (see TableLayout::calculate_layout_for method) | 
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| 323 | invalid_mut(index + 1) | 
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| 324 | } else { | 
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| 325 | base.as_ptr().sub(index) | 
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| 326 | }; | 
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| 327 | Self { | 
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| 328 | ptr: NonNull::new_unchecked(ptr), | 
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| 329 | } | 
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| 330 | } | 
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| 331 |  | 
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| 332 | /// Calculates the index of a [`Bucket`] as distance between two pointers | 
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| 333 | /// (convenience for `base.as_ptr().offset_from(self.ptr.as_ptr()) as usize`). | 
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| 334 | /// The returned value is in units of T: the distance in bytes divided by | 
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| 335 | /// [`core::mem::size_of::<T>()`]. | 
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| 336 | /// | 
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| 337 | /// If the `T` is a ZST, then we return the index of the element in | 
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| 338 | /// the table so that `erase` works properly (return `self.ptr.as_ptr() as usize - 1`). | 
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| 339 | /// | 
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| 340 | /// This function is the inverse of [`from_base_index`]. | 
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| 341 | /// | 
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| 342 | /// # Safety | 
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| 343 | /// | 
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| 344 | /// If `mem::size_of::<T>() != 0`, then the safety rules are directly derived | 
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| 345 | /// from the safety rules for [`<*const T>::offset_from`] method of `*const T`. | 
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| 346 | /// | 
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| 347 | /// Thus, in order to uphold the safety contracts for [`<*const T>::offset_from`] | 
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| 348 | /// method, as well as for the correct logic of the work of this crate, the | 
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| 349 | /// following rules are necessary and sufficient: | 
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| 350 | /// | 
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| 351 | /// * `base` contained pointer must not be `dangling` and must point to the | 
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| 352 | ///   end of the first `element` from the `data part` of the table, i.e. | 
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| 353 | ///   must be a pointer that returns by [`RawTable::data_end`] or by | 
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| 354 | ///   [`RawTableInner::data_end<T>`]; | 
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| 355 | /// | 
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| 356 | /// * `self` also must not contain dangling pointer; | 
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| 357 | /// | 
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| 358 | /// * both `self` and `base` must be created from the same [`RawTable`] | 
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| 359 | ///   (or [`RawTableInner`]). | 
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| 360 | /// | 
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| 361 | /// If `mem::size_of::<T>() == 0`, this function is always safe. | 
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| 362 | /// | 
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| 363 | /// [`Bucket`]: crate::raw::Bucket | 
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| 364 | /// [`from_base_index`]: crate::raw::Bucket::from_base_index | 
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| 365 | /// [`RawTable::data_end`]: crate::raw::RawTable::data_end | 
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| 366 | /// [`RawTableInner::data_end<T>`]: RawTableInner::data_end<T> | 
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| 367 | /// [`RawTable`]: crate::raw::RawTable | 
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| 368 | /// [`RawTableInner`]: RawTableInner | 
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| 369 | /// [`<*const T>::offset_from`]: https://doc.rust-lang.org/nightly/core/primitive.pointer.html#method.offset_from | 
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| 370 | #[ inline] | 
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| 371 | unsafe fn to_base_index(&self, base: NonNull<T>) -> usize { | 
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| 372 | // If mem::size_of::<T>() != 0 then return an index under which we used to store the | 
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| 373 | // `element` in the data part of the table (we start counting from "0", so | 
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| 374 | // that in the expression T[last], the "last" index actually is one less than the | 
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| 375 | // "buckets" number in the table, i.e. "last = RawTableInner.bucket_mask"). | 
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| 376 | // For example for 5th element in table calculation is performed like this: | 
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| 377 | // | 
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| 378 | //                        mem::size_of::<T>() | 
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| 379 | //                          | | 
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| 380 | //                          |         `self = from_base_index(base, 5)` that returns pointer | 
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| 381 | //                          |         that points here in the data part of the table | 
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| 382 | //                          |         (to the end of T5) | 
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| 383 | //                          |           |                    `base: NonNull<T>` must point here | 
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| 384 | //                          v           |                    (to the end of T0 or to the start of C0) | 
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| 385 | //                        /???\         v                      v | 
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| 386 | // [Padding], Tlast, ..., |T10|, ..., T5|, T4, T3, T2, T1, T0, |C0, C1, C2, C3, C4, C5, ..., C10, ..., Clast | 
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| 387 | //                                      \__________  __________/ | 
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| 388 | //                                                 \/ | 
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| 389 | //                                     `bucket.to_base_index(base)` = 5 | 
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| 390 | //                                     (base.as_ptr() as usize - self.ptr.as_ptr() as usize) / mem::size_of::<T>() | 
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| 391 | // | 
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| 392 | // where: T0...Tlast - our stored data; C0...Clast - control bytes or metadata for data. | 
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| 393 | if T::IS_ZERO_SIZED { | 
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| 394 | // this can not be UB | 
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| 395 | self.ptr.as_ptr() as usize - 1 | 
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| 396 | } else { | 
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| 397 | offset_from(base.as_ptr(), self.ptr.as_ptr()) | 
|---|
| 398 | } | 
|---|
| 399 | } | 
|---|
| 400 |  | 
|---|
| 401 | /// Acquires the underlying raw pointer `*mut T` to `data`. | 
|---|
| 402 | /// | 
|---|
| 403 | /// # Note | 
|---|
| 404 | /// | 
|---|
| 405 | /// If `T` is not [`Copy`], do not use `*mut T` methods that can cause calling the | 
|---|
| 406 | /// destructor of `T` (for example the [`<*mut T>::drop_in_place`] method), because | 
|---|
| 407 | /// for properly dropping the data we also need to clear `data` control bytes. If we | 
|---|
| 408 | /// drop data, but do not clear `data control byte` it leads to double drop when | 
|---|
| 409 | /// [`RawTable`] goes out of scope. | 
|---|
| 410 | /// | 
|---|
| 411 | /// If you modify an already initialized `value`, so [`Hash`] and [`Eq`] on the new | 
|---|
| 412 | /// `T` value and its borrowed form *must* match those for the old `T` value, as the map | 
|---|
| 413 | /// will not re-evaluate where the new value should go, meaning the value may become | 
|---|
| 414 | /// "lost" if their location does not reflect their state. | 
|---|
| 415 | /// | 
|---|
| 416 | /// [`RawTable`]: crate::raw::RawTable | 
|---|
| 417 | /// [`<*mut T>::drop_in_place`]: https://doc.rust-lang.org/core/primitive.pointer.html#method.drop_in_place | 
|---|
| 418 | /// [`Hash`]: https://doc.rust-lang.org/core/hash/trait.Hash.html | 
|---|
| 419 | /// [`Eq`]: https://doc.rust-lang.org/core/cmp/trait.Eq.html | 
|---|
| 420 | #[ inline] | 
|---|
| 421 | pub fn as_ptr(&self) -> *mut T { | 
|---|
| 422 | if T::IS_ZERO_SIZED { | 
|---|
| 423 | // Just return an arbitrary ZST pointer which is properly aligned | 
|---|
| 424 | // invalid pointer is good enough for ZST | 
|---|
| 425 | invalid_mut(mem::align_of::<T>()) | 
|---|
| 426 | } else { | 
|---|
| 427 | unsafe { self.ptr.as_ptr().sub(1) } | 
|---|
| 428 | } | 
|---|
| 429 | } | 
|---|
| 430 |  | 
|---|
| 431 | /// Acquires the underlying non-null pointer `*mut T` to `data`. | 
|---|
| 432 | #[ inline] | 
|---|
| 433 | fn as_non_null(&self) -> NonNull<T> { | 
|---|
| 434 | // SAFETY: `self.ptr` is already a `NonNull` | 
|---|
| 435 | unsafe { NonNull::new_unchecked(self.as_ptr()) } | 
|---|
| 436 | } | 
|---|
| 437 |  | 
|---|
| 438 | /// Create a new [`Bucket`] that is offset from the `self` by the given | 
|---|
| 439 | /// `offset`. The pointer calculation is performed by calculating the | 
|---|
| 440 | /// offset from `self` pointer (convenience for `self.ptr.as_ptr().sub(offset)`). | 
|---|
| 441 | /// This function is used for iterators. | 
|---|
| 442 | /// | 
|---|
| 443 | /// `offset` is in units of `T`; e.g., a `offset` of 3 represents a pointer | 
|---|
| 444 | /// offset of `3 * size_of::<T>()` bytes. | 
|---|
| 445 | /// | 
|---|
| 446 | /// # Safety | 
|---|
| 447 | /// | 
|---|
| 448 | /// If `mem::size_of::<T>() != 0`, then the safety rules are directly derived | 
|---|
| 449 | /// from the safety rules for [`<*mut T>::sub`] method of `*mut T` and safety | 
|---|
| 450 | /// rules of [`NonNull::new_unchecked`] function. | 
|---|
| 451 | /// | 
|---|
| 452 | /// Thus, in order to uphold the safety contracts for [`<*mut T>::sub`] method | 
|---|
| 453 | /// and [`NonNull::new_unchecked`] function, as well as for the correct | 
|---|
| 454 | /// logic of the work of this crate, the following rules are necessary and | 
|---|
| 455 | /// sufficient: | 
|---|
| 456 | /// | 
|---|
| 457 | /// * `self` contained pointer must not be `dangling`; | 
|---|
| 458 | /// | 
|---|
| 459 | /// * `self.to_base_index() + offset` must not be greater than `RawTableInner.bucket_mask`, | 
|---|
| 460 | ///   i.e. `(self.to_base_index() + offset) <= RawTableInner.bucket_mask` or, in other | 
|---|
| 461 | ///   words, `self.to_base_index() + offset + 1` must be no greater than the number returned | 
|---|
| 462 | ///   by the function [`RawTable::buckets`] or [`RawTableInner::buckets`]. | 
|---|
| 463 | /// | 
|---|
| 464 | /// If `mem::size_of::<T>() == 0`, then the only requirement is that the | 
|---|
| 465 | /// `self.to_base_index() + offset` must not be greater than `RawTableInner.bucket_mask`, | 
|---|
| 466 | /// i.e. `(self.to_base_index() + offset) <= RawTableInner.bucket_mask` or, in other words, | 
|---|
| 467 | /// `self.to_base_index() + offset + 1` must be no greater than the number returned by the | 
|---|
| 468 | /// function [`RawTable::buckets`] or [`RawTableInner::buckets`]. | 
|---|
| 469 | /// | 
|---|
| 470 | /// [`Bucket`]: crate::raw::Bucket | 
|---|
| 471 | /// [`<*mut T>::sub`]: https://doc.rust-lang.org/core/primitive.pointer.html#method.sub-1 | 
|---|
| 472 | /// [`NonNull::new_unchecked`]: https://doc.rust-lang.org/stable/std/ptr/struct.NonNull.html#method.new_unchecked | 
|---|
| 473 | /// [`RawTable::buckets`]: crate::raw::RawTable::buckets | 
|---|
| 474 | /// [`RawTableInner::buckets`]: RawTableInner::buckets | 
|---|
| 475 | #[ inline] | 
|---|
| 476 | unsafe fn next_n(&self, offset: usize) -> Self { | 
|---|
| 477 | let ptr = if T::IS_ZERO_SIZED { | 
|---|
| 478 | // invalid pointer is good enough for ZST | 
|---|
| 479 | invalid_mut(self.ptr.as_ptr() as usize + offset) | 
|---|
| 480 | } else { | 
|---|
| 481 | self.ptr.as_ptr().sub(offset) | 
|---|
| 482 | }; | 
|---|
| 483 | Self { | 
|---|
| 484 | ptr: NonNull::new_unchecked(ptr), | 
|---|
| 485 | } | 
|---|
| 486 | } | 
|---|
| 487 |  | 
|---|
| 488 | /// Executes the destructor (if any) of the pointed-to `data`. | 
|---|
| 489 | /// | 
|---|
| 490 | /// # Safety | 
|---|
| 491 | /// | 
|---|
| 492 | /// See [`ptr::drop_in_place`] for safety concerns. | 
|---|
| 493 | /// | 
|---|
| 494 | /// You should use [`RawTable::erase`] instead of this function, | 
|---|
| 495 | /// or be careful with calling this function directly, because for | 
|---|
| 496 | /// properly dropping the data we need also clear `data` control bytes. | 
|---|
| 497 | /// If we drop data, but do not erase `data control byte` it leads to | 
|---|
| 498 | /// double drop when [`RawTable`] goes out of scope. | 
|---|
| 499 | /// | 
|---|
| 500 | /// [`ptr::drop_in_place`]: https://doc.rust-lang.org/core/ptr/fn.drop_in_place.html | 
|---|
| 501 | /// [`RawTable`]: crate::raw::RawTable | 
|---|
| 502 | /// [`RawTable::erase`]: crate::raw::RawTable::erase | 
|---|
| 503 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 504 | pub(crate) unsafe fn drop(&self) { | 
|---|
| 505 | self.as_ptr().drop_in_place(); | 
|---|
| 506 | } | 
|---|
| 507 |  | 
|---|
| 508 | /// Reads the `value` from `self` without moving it. This leaves the | 
|---|
| 509 | /// memory in `self` unchanged. | 
|---|
| 510 | /// | 
|---|
| 511 | /// # Safety | 
|---|
| 512 | /// | 
|---|
| 513 | /// See [`ptr::read`] for safety concerns. | 
|---|
| 514 | /// | 
|---|
| 515 | /// You should use [`RawTable::remove`] instead of this function, | 
|---|
| 516 | /// or be careful with calling this function directly, because compiler | 
|---|
| 517 | /// calls its destructor when the read `value` goes out of scope. It | 
|---|
| 518 | /// can cause double dropping when [`RawTable`] goes out of scope, | 
|---|
| 519 | /// because of not erased `data control byte`. | 
|---|
| 520 | /// | 
|---|
| 521 | /// [`ptr::read`]: https://doc.rust-lang.org/core/ptr/fn.read.html | 
|---|
| 522 | /// [`RawTable`]: crate::raw::RawTable | 
|---|
| 523 | /// [`RawTable::remove`]: crate::raw::RawTable::remove | 
|---|
| 524 | #[ inline] | 
|---|
| 525 | pub(crate) unsafe fn read(&self) -> T { | 
|---|
| 526 | self.as_ptr().read() | 
|---|
| 527 | } | 
|---|
| 528 |  | 
|---|
| 529 | /// Overwrites a memory location with the given `value` without reading | 
|---|
| 530 | /// or dropping the old value (like [`ptr::write`] function). | 
|---|
| 531 | /// | 
|---|
| 532 | /// # Safety | 
|---|
| 533 | /// | 
|---|
| 534 | /// See [`ptr::write`] for safety concerns. | 
|---|
| 535 | /// | 
|---|
| 536 | /// # Note | 
|---|
| 537 | /// | 
|---|
| 538 | /// [`Hash`] and [`Eq`] on the new `T` value and its borrowed form *must* match | 
|---|
| 539 | /// those for the old `T` value, as the map will not re-evaluate where the new | 
|---|
| 540 | /// value should go, meaning the value may become "lost" if their location | 
|---|
| 541 | /// does not reflect their state. | 
|---|
| 542 | /// | 
|---|
| 543 | /// [`ptr::write`]: https://doc.rust-lang.org/core/ptr/fn.write.html | 
|---|
| 544 | /// [`Hash`]: https://doc.rust-lang.org/core/hash/trait.Hash.html | 
|---|
| 545 | /// [`Eq`]: https://doc.rust-lang.org/core/cmp/trait.Eq.html | 
|---|
| 546 | #[ inline] | 
|---|
| 547 | pub(crate) unsafe fn write(&self, val: T) { | 
|---|
| 548 | self.as_ptr().write(val); | 
|---|
| 549 | } | 
|---|
| 550 |  | 
|---|
| 551 | /// Returns a shared immutable reference to the `value`. | 
|---|
| 552 | /// | 
|---|
| 553 | /// # Safety | 
|---|
| 554 | /// | 
|---|
| 555 | /// See [`NonNull::as_ref`] for safety concerns. | 
|---|
| 556 | /// | 
|---|
| 557 | /// [`NonNull::as_ref`]: https://doc.rust-lang.org/core/ptr/struct.NonNull.html#method.as_ref | 
|---|
| 558 | #[ inline] | 
|---|
| 559 | pub unsafe fn as_ref<'a>(&self) -> &'a T { | 
|---|
| 560 | &*self.as_ptr() | 
|---|
| 561 | } | 
|---|
| 562 |  | 
|---|
| 563 | /// Returns a unique mutable reference to the `value`. | 
|---|
| 564 | /// | 
|---|
| 565 | /// # Safety | 
|---|
| 566 | /// | 
|---|
| 567 | /// See [`NonNull::as_mut`] for safety concerns. | 
|---|
| 568 | /// | 
|---|
| 569 | /// # Note | 
|---|
| 570 | /// | 
|---|
| 571 | /// [`Hash`] and [`Eq`] on the new `T` value and its borrowed form *must* match | 
|---|
| 572 | /// those for the old `T` value, as the map will not re-evaluate where the new | 
|---|
| 573 | /// value should go, meaning the value may become "lost" if their location | 
|---|
| 574 | /// does not reflect their state. | 
|---|
| 575 | /// | 
|---|
| 576 | /// [`NonNull::as_mut`]: https://doc.rust-lang.org/core/ptr/struct.NonNull.html#method.as_mut | 
|---|
| 577 | /// [`Hash`]: https://doc.rust-lang.org/core/hash/trait.Hash.html | 
|---|
| 578 | /// [`Eq`]: https://doc.rust-lang.org/core/cmp/trait.Eq.html | 
|---|
| 579 | #[ inline] | 
|---|
| 580 | pub unsafe fn as_mut<'a>(&self) -> &'a mut T { | 
|---|
| 581 | &mut *self.as_ptr() | 
|---|
| 582 | } | 
|---|
| 583 | } | 
|---|
| 584 |  | 
|---|
| 585 | /// A raw hash table with an unsafe API. | 
|---|
| 586 | pub struct RawTable<T, A: Allocator = Global> { | 
|---|
| 587 | table: RawTableInner, | 
|---|
| 588 | alloc: A, | 
|---|
| 589 | // Tell dropck that we own instances of T. | 
|---|
| 590 | marker: PhantomData<T>, | 
|---|
| 591 | } | 
|---|
| 592 |  | 
|---|
| 593 | /// Non-generic part of `RawTable` which allows functions to be instantiated only once regardless | 
|---|
| 594 | /// of how many different key-value types are used. | 
|---|
| 595 | struct RawTableInner { | 
|---|
| 596 | // Mask to get an index from a hash value. The value is one less than the | 
|---|
| 597 | // number of buckets in the table. | 
|---|
| 598 | bucket_mask: usize, | 
|---|
| 599 |  | 
|---|
| 600 | // [Padding], T_n, ..., T1, T0, C0, C1, ... | 
|---|
| 601 | //                              ^ points here | 
|---|
| 602 | ctrl: NonNull<u8>, | 
|---|
| 603 |  | 
|---|
| 604 | // Number of elements that can be inserted before we need to grow the table | 
|---|
| 605 | growth_left: usize, | 
|---|
| 606 |  | 
|---|
| 607 | // Number of elements in the table, only really used by len() | 
|---|
| 608 | items: usize, | 
|---|
| 609 | } | 
|---|
| 610 |  | 
|---|
| 611 | impl<T> RawTable<T, Global> { | 
|---|
| 612 | /// Creates a new empty hash table without allocating any memory. | 
|---|
| 613 | /// | 
|---|
| 614 | /// In effect this returns a table with exactly 1 bucket. However we can | 
|---|
| 615 | /// leave the data pointer dangling since that bucket is never written to | 
|---|
| 616 | /// due to our load factor forcing us to always have at least 1 free bucket. | 
|---|
| 617 | #[ inline] | 
|---|
| 618 | #[ cfg_attr(feature = "rustc-dep-of-std", rustc_const_stable_indirect)] | 
|---|
| 619 | pub const fn new() -> Self { | 
|---|
| 620 | Self { | 
|---|
| 621 | table: RawTableInner::NEW, | 
|---|
| 622 | alloc: Global, | 
|---|
| 623 | marker: PhantomData, | 
|---|
| 624 | } | 
|---|
| 625 | } | 
|---|
| 626 |  | 
|---|
| 627 | /// Allocates a new hash table with at least enough capacity for inserting | 
|---|
| 628 | /// the given number of elements without reallocating. | 
|---|
| 629 | pub fn with_capacity(capacity: usize) -> Self { | 
|---|
| 630 | Self::with_capacity_in(capacity, alloc:Global) | 
|---|
| 631 | } | 
|---|
| 632 | } | 
|---|
| 633 |  | 
|---|
| 634 | impl<T, A: Allocator> RawTable<T, A> { | 
|---|
| 635 | const TABLE_LAYOUT: TableLayout = TableLayout::new::<T>(); | 
|---|
| 636 |  | 
|---|
| 637 | /// Creates a new empty hash table without allocating any memory, using the | 
|---|
| 638 | /// given allocator. | 
|---|
| 639 | /// | 
|---|
| 640 | /// In effect this returns a table with exactly 1 bucket. However we can | 
|---|
| 641 | /// leave the data pointer dangling since that bucket is never written to | 
|---|
| 642 | /// due to our load factor forcing us to always have at least 1 free bucket. | 
|---|
| 643 | #[ inline] | 
|---|
| 644 | #[ cfg_attr(feature = "rustc-dep-of-std", rustc_const_stable_indirect)] | 
|---|
| 645 | pub const fn new_in(alloc: A) -> Self { | 
|---|
| 646 | Self { | 
|---|
| 647 | table: RawTableInner::NEW, | 
|---|
| 648 | alloc, | 
|---|
| 649 | marker: PhantomData, | 
|---|
| 650 | } | 
|---|
| 651 | } | 
|---|
| 652 |  | 
|---|
| 653 | /// Allocates a new hash table with the given number of buckets. | 
|---|
| 654 | /// | 
|---|
| 655 | /// The control bytes are left uninitialized. | 
|---|
| 656 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 657 | unsafe fn new_uninitialized( | 
|---|
| 658 | alloc: A, | 
|---|
| 659 | buckets: usize, | 
|---|
| 660 | fallibility: Fallibility, | 
|---|
| 661 | ) -> Result<Self, TryReserveError> { | 
|---|
| 662 | debug_assert!(buckets.is_power_of_two()); | 
|---|
| 663 |  | 
|---|
| 664 | Ok(Self { | 
|---|
| 665 | table: RawTableInner::new_uninitialized( | 
|---|
| 666 | &alloc, | 
|---|
| 667 | Self::TABLE_LAYOUT, | 
|---|
| 668 | buckets, | 
|---|
| 669 | fallibility, | 
|---|
| 670 | )?, | 
|---|
| 671 | alloc, | 
|---|
| 672 | marker: PhantomData, | 
|---|
| 673 | }) | 
|---|
| 674 | } | 
|---|
| 675 |  | 
|---|
| 676 | /// Allocates a new hash table using the given allocator, with at least enough capacity for | 
|---|
| 677 | /// inserting the given number of elements without reallocating. | 
|---|
| 678 | pub fn with_capacity_in(capacity: usize, alloc: A) -> Self { | 
|---|
| 679 | Self { | 
|---|
| 680 | table: RawTableInner::with_capacity(&alloc, Self::TABLE_LAYOUT, capacity), | 
|---|
| 681 | alloc, | 
|---|
| 682 | marker: PhantomData, | 
|---|
| 683 | } | 
|---|
| 684 | } | 
|---|
| 685 |  | 
|---|
| 686 | /// Returns a reference to the underlying allocator. | 
|---|
| 687 | #[ inline] | 
|---|
| 688 | pub fn allocator(&self) -> &A { | 
|---|
| 689 | &self.alloc | 
|---|
| 690 | } | 
|---|
| 691 |  | 
|---|
| 692 | /// Returns pointer to one past last `data` element in the table as viewed from | 
|---|
| 693 | /// the start point of the allocation. | 
|---|
| 694 | /// | 
|---|
| 695 | /// The caller must ensure that the `RawTable` outlives the returned [`NonNull<T>`], | 
|---|
| 696 | /// otherwise using it may result in [`undefined behavior`]. | 
|---|
| 697 | /// | 
|---|
| 698 | /// [`undefined behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 699 | #[ inline] | 
|---|
| 700 | pub fn data_end(&self) -> NonNull<T> { | 
|---|
| 701 | //                        `self.table.ctrl.cast()` returns pointer that | 
|---|
| 702 | //                        points here (to the end of `T0`) | 
|---|
| 703 | //                          ∨ | 
|---|
| 704 | // [Pad], T_n, ..., T1, T0, |CT0, CT1, ..., CT_n|, CTa_0, CTa_1, ..., CTa_m | 
|---|
| 705 | //                           \________  ________/ | 
|---|
| 706 | //                                    \/ | 
|---|
| 707 | //       `n = buckets - 1`, i.e. `RawTable::buckets() - 1` | 
|---|
| 708 | // | 
|---|
| 709 | // where: T0...T_n  - our stored data; | 
|---|
| 710 | //        CT0...CT_n - control bytes or metadata for `data`. | 
|---|
| 711 | //        CTa_0...CTa_m - additional control bytes, where `m = Group::WIDTH - 1` (so that the search | 
|---|
| 712 | //                        with loading `Group` bytes from the heap works properly, even if the result | 
|---|
| 713 | //                        of `h1(hash) & self.bucket_mask` is equal to `self.bucket_mask`). See also | 
|---|
| 714 | //                        `RawTableInner::set_ctrl` function. | 
|---|
| 715 | // | 
|---|
| 716 | // P.S. `h1(hash) & self.bucket_mask` is the same as `hash as usize % self.buckets()` because the number | 
|---|
| 717 | // of buckets is a power of two, and `self.bucket_mask = self.buckets() - 1`. | 
|---|
| 718 | self.table.ctrl.cast() | 
|---|
| 719 | } | 
|---|
| 720 |  | 
|---|
| 721 | /// Returns pointer to start of data table. | 
|---|
| 722 | #[ inline] | 
|---|
| 723 | #[ cfg(feature = "nightly")] | 
|---|
| 724 | pub unsafe fn data_start(&self) -> NonNull<T> { | 
|---|
| 725 | NonNull::new_unchecked(self.data_end().as_ptr().wrapping_sub(self.buckets())) | 
|---|
| 726 | } | 
|---|
| 727 |  | 
|---|
| 728 | /// Returns the total amount of memory allocated internally by the hash | 
|---|
| 729 | /// table, in bytes. | 
|---|
| 730 | /// | 
|---|
| 731 | /// The returned number is informational only. It is intended to be | 
|---|
| 732 | /// primarily used for memory profiling. | 
|---|
| 733 | #[ inline] | 
|---|
| 734 | pub fn allocation_size(&self) -> usize { | 
|---|
| 735 | // SAFETY: We use the same `table_layout` that was used to allocate | 
|---|
| 736 | // this table. | 
|---|
| 737 | unsafe { self.table.allocation_size_or_zero(Self::TABLE_LAYOUT) } | 
|---|
| 738 | } | 
|---|
| 739 |  | 
|---|
| 740 | /// Returns the index of a bucket from a `Bucket`. | 
|---|
| 741 | #[ inline] | 
|---|
| 742 | pub unsafe fn bucket_index(&self, bucket: &Bucket<T>) -> usize { | 
|---|
| 743 | bucket.to_base_index(self.data_end()) | 
|---|
| 744 | } | 
|---|
| 745 |  | 
|---|
| 746 | /// Returns a pointer to an element in the table. | 
|---|
| 747 | /// | 
|---|
| 748 | /// The caller must ensure that the `RawTable` outlives the returned [`Bucket<T>`], | 
|---|
| 749 | /// otherwise using it may result in [`undefined behavior`]. | 
|---|
| 750 | /// | 
|---|
| 751 | /// # Safety | 
|---|
| 752 | /// | 
|---|
| 753 | /// If `mem::size_of::<T>() != 0`, then the caller of this function must observe the | 
|---|
| 754 | /// following safety rules: | 
|---|
| 755 | /// | 
|---|
| 756 | /// * The table must already be allocated; | 
|---|
| 757 | /// | 
|---|
| 758 | /// * The `index` must not be greater than the number returned by the [`RawTable::buckets`] | 
|---|
| 759 | ///   function, i.e. `(index + 1) <= self.buckets()`. | 
|---|
| 760 | /// | 
|---|
| 761 | /// It is safe to call this function with index of zero (`index == 0`) on a table that has | 
|---|
| 762 | /// not been allocated, but using the returned [`Bucket`] results in [`undefined behavior`]. | 
|---|
| 763 | /// | 
|---|
| 764 | /// If `mem::size_of::<T>() == 0`, then the only requirement is that the `index` must | 
|---|
| 765 | /// not be greater than the number returned by the [`RawTable::buckets`] function, i.e. | 
|---|
| 766 | /// `(index + 1) <= self.buckets()`. | 
|---|
| 767 | /// | 
|---|
| 768 | /// [`RawTable::buckets`]: RawTable::buckets | 
|---|
| 769 | /// [`undefined behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 770 | #[ inline] | 
|---|
| 771 | pub unsafe fn bucket(&self, index: usize) -> Bucket<T> { | 
|---|
| 772 | // If mem::size_of::<T>() != 0 then return a pointer to the `element` in the `data part` of the table | 
|---|
| 773 | // (we start counting from "0", so that in the expression T[n], the "n" index actually one less than | 
|---|
| 774 | // the "buckets" number of our `RawTable`, i.e. "n = RawTable::buckets() - 1"): | 
|---|
| 775 | // | 
|---|
| 776 | //           `table.bucket(3).as_ptr()` returns a pointer that points here in the `data` | 
|---|
| 777 | //           part of the `RawTable`, i.e. to the start of T3 (see `Bucket::as_ptr`) | 
|---|
| 778 | //                  | | 
|---|
| 779 | //                  |               `base = self.data_end()` points here | 
|---|
| 780 | //                  |               (to the start of CT0 or to the end of T0) | 
|---|
| 781 | //                  v                 v | 
|---|
| 782 | // [Pad], T_n, ..., |T3|, T2, T1, T0, |CT0, CT1, CT2, CT3, ..., CT_n, CTa_0, CTa_1, ..., CTa_m | 
|---|
| 783 | //                     ^                                              \__________  __________/ | 
|---|
| 784 | //        `table.bucket(3)` returns a pointer that points                        \/ | 
|---|
| 785 | //         here in the `data` part of the `RawTable` (to              additional control bytes | 
|---|
| 786 | //         the end of T3)                                              `m = Group::WIDTH - 1` | 
|---|
| 787 | // | 
|---|
| 788 | // where: T0...T_n  - our stored data; | 
|---|
| 789 | //        CT0...CT_n - control bytes or metadata for `data`; | 
|---|
| 790 | //        CTa_0...CTa_m - additional control bytes (so that the search with loading `Group` bytes from | 
|---|
| 791 | //                        the heap works properly, even if the result of `h1(hash) & self.table.bucket_mask` | 
|---|
| 792 | //                        is equal to `self.table.bucket_mask`). See also `RawTableInner::set_ctrl` function. | 
|---|
| 793 | // | 
|---|
| 794 | // P.S. `h1(hash) & self.table.bucket_mask` is the same as `hash as usize % self.buckets()` because the number | 
|---|
| 795 | // of buckets is a power of two, and `self.table.bucket_mask = self.buckets() - 1`. | 
|---|
| 796 | debug_assert_ne!(self.table.bucket_mask, 0); | 
|---|
| 797 | debug_assert!(index < self.buckets()); | 
|---|
| 798 | Bucket::from_base_index(self.data_end(), index) | 
|---|
| 799 | } | 
|---|
| 800 |  | 
|---|
| 801 | /// Erases an element from the table without dropping it. | 
|---|
| 802 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 803 | unsafe fn erase_no_drop(&mut self, item: &Bucket<T>) { | 
|---|
| 804 | let index = self.bucket_index(item); | 
|---|
| 805 | self.table.erase(index); | 
|---|
| 806 | } | 
|---|
| 807 |  | 
|---|
| 808 | /// Erases an element from the table, dropping it in place. | 
|---|
| 809 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 810 | #[ allow(clippy::needless_pass_by_value)] | 
|---|
| 811 | pub unsafe fn erase(&mut self, item: Bucket<T>) { | 
|---|
| 812 | // Erase the element from the table first since drop might panic. | 
|---|
| 813 | self.erase_no_drop(&item); | 
|---|
| 814 | item.drop(); | 
|---|
| 815 | } | 
|---|
| 816 |  | 
|---|
| 817 | /// Removes an element from the table, returning it. | 
|---|
| 818 | /// | 
|---|
| 819 | /// This also returns an `InsertSlot` pointing to the newly free bucket. | 
|---|
| 820 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 821 | #[ allow(clippy::needless_pass_by_value)] | 
|---|
| 822 | pub unsafe fn remove(&mut self, item: Bucket<T>) -> (T, InsertSlot) { | 
|---|
| 823 | self.erase_no_drop(&item); | 
|---|
| 824 | ( | 
|---|
| 825 | item.read(), | 
|---|
| 826 | InsertSlot { | 
|---|
| 827 | index: self.bucket_index(&item), | 
|---|
| 828 | }, | 
|---|
| 829 | ) | 
|---|
| 830 | } | 
|---|
| 831 |  | 
|---|
| 832 | /// Finds and removes an element from the table, returning it. | 
|---|
| 833 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 834 | pub fn remove_entry(&mut self, hash: u64, eq: impl FnMut(&T) -> bool) -> Option<T> { | 
|---|
| 835 | // Avoid `Option::map` because it bloats LLVM IR. | 
|---|
| 836 | match self.find(hash, eq) { | 
|---|
| 837 | Some(bucket) => Some(unsafe { self.remove(bucket).0 }), | 
|---|
| 838 | None => None, | 
|---|
| 839 | } | 
|---|
| 840 | } | 
|---|
| 841 |  | 
|---|
| 842 | /// Marks all table buckets as empty without dropping their contents. | 
|---|
| 843 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 844 | pub fn clear_no_drop(&mut self) { | 
|---|
| 845 | self.table.clear_no_drop(); | 
|---|
| 846 | } | 
|---|
| 847 |  | 
|---|
| 848 | /// Removes all elements from the table without freeing the backing memory. | 
|---|
| 849 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 850 | pub fn clear(&mut self) { | 
|---|
| 851 | if self.is_empty() { | 
|---|
| 852 | // Special case empty table to avoid surprising O(capacity) time. | 
|---|
| 853 | return; | 
|---|
| 854 | } | 
|---|
| 855 | // Ensure that the table is reset even if one of the drops panic | 
|---|
| 856 | let mut self_ = guard(self, |self_| self_.clear_no_drop()); | 
|---|
| 857 | unsafe { | 
|---|
| 858 | // SAFETY: ScopeGuard sets to zero the `items` field of the table | 
|---|
| 859 | // even in case of panic during the dropping of the elements so | 
|---|
| 860 | // that there will be no double drop of the elements. | 
|---|
| 861 | self_.table.drop_elements::<T>(); | 
|---|
| 862 | } | 
|---|
| 863 | } | 
|---|
| 864 |  | 
|---|
| 865 | /// Shrinks the table to fit `max(self.len(), min_size)` elements. | 
|---|
| 866 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 867 | pub fn shrink_to(&mut self, min_size: usize, hasher: impl Fn(&T) -> u64) { | 
|---|
| 868 | // Calculate the minimal number of elements that we need to reserve | 
|---|
| 869 | // space for. | 
|---|
| 870 | let min_size = usize::max(self.table.items, min_size); | 
|---|
| 871 | if min_size == 0 { | 
|---|
| 872 | let mut old_inner = mem::replace(&mut self.table, RawTableInner::NEW); | 
|---|
| 873 | unsafe { | 
|---|
| 874 | // SAFETY: | 
|---|
| 875 | // 1. We call the function only once; | 
|---|
| 876 | // 2. We know for sure that `alloc` and `table_layout` matches the [`Allocator`] | 
|---|
| 877 | //    and [`TableLayout`] that were used to allocate this table. | 
|---|
| 878 | // 3. If any elements' drop function panics, then there will only be a memory leak, | 
|---|
| 879 | //    because we have replaced the inner table with a new one. | 
|---|
| 880 | old_inner.drop_inner_table::<T, _>(&self.alloc, Self::TABLE_LAYOUT); | 
|---|
| 881 | } | 
|---|
| 882 | return; | 
|---|
| 883 | } | 
|---|
| 884 |  | 
|---|
| 885 | // Calculate the number of buckets that we need for this number of | 
|---|
| 886 | // elements. If the calculation overflows then the requested bucket | 
|---|
| 887 | // count must be larger than what we have right and nothing needs to be | 
|---|
| 888 | // done. | 
|---|
| 889 | let min_buckets = match capacity_to_buckets(min_size, Self::TABLE_LAYOUT) { | 
|---|
| 890 | Some(buckets) => buckets, | 
|---|
| 891 | None => return, | 
|---|
| 892 | }; | 
|---|
| 893 |  | 
|---|
| 894 | // If we have more buckets than we need, shrink the table. | 
|---|
| 895 | if min_buckets < self.buckets() { | 
|---|
| 896 | // Fast path if the table is empty | 
|---|
| 897 | if self.table.items == 0 { | 
|---|
| 898 | let new_inner = | 
|---|
| 899 | RawTableInner::with_capacity(&self.alloc, Self::TABLE_LAYOUT, min_size); | 
|---|
| 900 | let mut old_inner = mem::replace(&mut self.table, new_inner); | 
|---|
| 901 | unsafe { | 
|---|
| 902 | // SAFETY: | 
|---|
| 903 | // 1. We call the function only once; | 
|---|
| 904 | // 2. We know for sure that `alloc` and `table_layout` matches the [`Allocator`] | 
|---|
| 905 | //    and [`TableLayout`] that were used to allocate this table. | 
|---|
| 906 | // 3. If any elements' drop function panics, then there will only be a memory leak, | 
|---|
| 907 | //    because we have replaced the inner table with a new one. | 
|---|
| 908 | old_inner.drop_inner_table::<T, _>(&self.alloc, Self::TABLE_LAYOUT); | 
|---|
| 909 | } | 
|---|
| 910 | } else { | 
|---|
| 911 | // Avoid `Result::unwrap_or_else` because it bloats LLVM IR. | 
|---|
| 912 | unsafe { | 
|---|
| 913 | // SAFETY: | 
|---|
| 914 | // 1. We know for sure that `min_size >= self.table.items`. | 
|---|
| 915 | // 2. The [`RawTableInner`] must already have properly initialized control bytes since | 
|---|
| 916 | //    we will never expose RawTable::new_uninitialized in a public API. | 
|---|
| 917 | if self | 
|---|
| 918 | .resize(min_size, hasher, Fallibility::Infallible) | 
|---|
| 919 | .is_err() | 
|---|
| 920 | { | 
|---|
| 921 | // SAFETY: The result of calling the `resize` function cannot be an error | 
|---|
| 922 | // because `fallibility == Fallibility::Infallible. | 
|---|
| 923 | hint::unreachable_unchecked() | 
|---|
| 924 | } | 
|---|
| 925 | } | 
|---|
| 926 | } | 
|---|
| 927 | } | 
|---|
| 928 | } | 
|---|
| 929 |  | 
|---|
| 930 | /// Ensures that at least `additional` items can be inserted into the table | 
|---|
| 931 | /// without reallocation. | 
|---|
| 932 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 933 | pub fn reserve(&mut self, additional: usize, hasher: impl Fn(&T) -> u64) { | 
|---|
| 934 | if unlikely(additional > self.table.growth_left) { | 
|---|
| 935 | // Avoid `Result::unwrap_or_else` because it bloats LLVM IR. | 
|---|
| 936 | unsafe { | 
|---|
| 937 | // SAFETY: The [`RawTableInner`] must already have properly initialized control | 
|---|
| 938 | // bytes since we will never expose RawTable::new_uninitialized in a public API. | 
|---|
| 939 | if self | 
|---|
| 940 | .reserve_rehash(additional, hasher, Fallibility::Infallible) | 
|---|
| 941 | .is_err() | 
|---|
| 942 | { | 
|---|
| 943 | // SAFETY: All allocation errors will be caught inside `RawTableInner::reserve_rehash`. | 
|---|
| 944 | hint::unreachable_unchecked() | 
|---|
| 945 | } | 
|---|
| 946 | } | 
|---|
| 947 | } | 
|---|
| 948 | } | 
|---|
| 949 |  | 
|---|
| 950 | /// Tries to ensure that at least `additional` items can be inserted into | 
|---|
| 951 | /// the table without reallocation. | 
|---|
| 952 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 953 | pub fn try_reserve( | 
|---|
| 954 | &mut self, | 
|---|
| 955 | additional: usize, | 
|---|
| 956 | hasher: impl Fn(&T) -> u64, | 
|---|
| 957 | ) -> Result<(), TryReserveError> { | 
|---|
| 958 | if additional > self.table.growth_left { | 
|---|
| 959 | // SAFETY: The [`RawTableInner`] must already have properly initialized control | 
|---|
| 960 | // bytes since we will never expose RawTable::new_uninitialized in a public API. | 
|---|
| 961 | unsafe { self.reserve_rehash(additional, hasher, Fallibility::Fallible) } | 
|---|
| 962 | } else { | 
|---|
| 963 | Ok(()) | 
|---|
| 964 | } | 
|---|
| 965 | } | 
|---|
| 966 |  | 
|---|
| 967 | /// Out-of-line slow path for `reserve` and `try_reserve`. | 
|---|
| 968 | /// | 
|---|
| 969 | /// # Safety | 
|---|
| 970 | /// | 
|---|
| 971 | /// The [`RawTableInner`] must have properly initialized control bytes, | 
|---|
| 972 | /// otherwise calling this function results in [`undefined behavior`] | 
|---|
| 973 | /// | 
|---|
| 974 | /// [`undefined behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 975 | #[ cold] | 
|---|
| 976 | #[ inline(never)] | 
|---|
| 977 | unsafe fn reserve_rehash( | 
|---|
| 978 | &mut self, | 
|---|
| 979 | additional: usize, | 
|---|
| 980 | hasher: impl Fn(&T) -> u64, | 
|---|
| 981 | fallibility: Fallibility, | 
|---|
| 982 | ) -> Result<(), TryReserveError> { | 
|---|
| 983 | unsafe { | 
|---|
| 984 | // SAFETY: | 
|---|
| 985 | // 1. We know for sure that `alloc` and `layout` matches the [`Allocator`] and | 
|---|
| 986 | //    [`TableLayout`] that were used to allocate this table. | 
|---|
| 987 | // 2. The `drop` function is the actual drop function of the elements stored in | 
|---|
| 988 | //    the table. | 
|---|
| 989 | // 3. The caller ensures that the control bytes of the `RawTableInner` | 
|---|
| 990 | //    are already initialized. | 
|---|
| 991 | self.table.reserve_rehash_inner( | 
|---|
| 992 | &self.alloc, | 
|---|
| 993 | additional, | 
|---|
| 994 | &|table, index| hasher(table.bucket::<T>(index).as_ref()), | 
|---|
| 995 | fallibility, | 
|---|
| 996 | Self::TABLE_LAYOUT, | 
|---|
| 997 | if T::NEEDS_DROP { | 
|---|
| 998 | Some(|ptr| ptr::drop_in_place(ptr as *mut T)) | 
|---|
| 999 | } else { | 
|---|
| 1000 | None | 
|---|
| 1001 | }, | 
|---|
| 1002 | ) | 
|---|
| 1003 | } | 
|---|
| 1004 | } | 
|---|
| 1005 |  | 
|---|
| 1006 | /// Allocates a new table of a different size and moves the contents of the | 
|---|
| 1007 | /// current table into it. | 
|---|
| 1008 | /// | 
|---|
| 1009 | /// # Safety | 
|---|
| 1010 | /// | 
|---|
| 1011 | /// The [`RawTableInner`] must have properly initialized control bytes, | 
|---|
| 1012 | /// otherwise calling this function results in [`undefined behavior`] | 
|---|
| 1013 | /// | 
|---|
| 1014 | /// The caller of this function must ensure that `capacity >= self.table.items` | 
|---|
| 1015 | /// otherwise: | 
|---|
| 1016 | /// | 
|---|
| 1017 | /// * If `self.table.items != 0`, calling of this function with `capacity` | 
|---|
| 1018 | ///   equal to 0 (`capacity == 0`) results in [`undefined behavior`]. | 
|---|
| 1019 | /// | 
|---|
| 1020 | /// * If `self.table.items > capacity_to_buckets(capacity, Self::TABLE_LAYOUT)` | 
|---|
| 1021 | ///   calling this function are never return (will loop infinitely). | 
|---|
| 1022 | /// | 
|---|
| 1023 | /// See [`RawTableInner::find_insert_slot`] for more information. | 
|---|
| 1024 | /// | 
|---|
| 1025 | /// [`RawTableInner::find_insert_slot`]: RawTableInner::find_insert_slot | 
|---|
| 1026 | /// [`undefined behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 1027 | unsafe fn resize( | 
|---|
| 1028 | &mut self, | 
|---|
| 1029 | capacity: usize, | 
|---|
| 1030 | hasher: impl Fn(&T) -> u64, | 
|---|
| 1031 | fallibility: Fallibility, | 
|---|
| 1032 | ) -> Result<(), TryReserveError> { | 
|---|
| 1033 | // SAFETY: | 
|---|
| 1034 | // 1. The caller of this function guarantees that `capacity >= self.table.items`. | 
|---|
| 1035 | // 2. We know for sure that `alloc` and `layout` matches the [`Allocator`] and | 
|---|
| 1036 | //    [`TableLayout`] that were used to allocate this table. | 
|---|
| 1037 | // 3. The caller ensures that the control bytes of the `RawTableInner` | 
|---|
| 1038 | //    are already initialized. | 
|---|
| 1039 | self.table.resize_inner( | 
|---|
| 1040 | &self.alloc, | 
|---|
| 1041 | capacity, | 
|---|
| 1042 | &|table, index| hasher(table.bucket::<T>(index).as_ref()), | 
|---|
| 1043 | fallibility, | 
|---|
| 1044 | Self::TABLE_LAYOUT, | 
|---|
| 1045 | ) | 
|---|
| 1046 | } | 
|---|
| 1047 |  | 
|---|
| 1048 | /// Inserts a new element into the table, and returns its raw bucket. | 
|---|
| 1049 | /// | 
|---|
| 1050 | /// This does not check if the given element already exists in the table. | 
|---|
| 1051 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 1052 | pub fn insert(&mut self, hash: u64, value: T, hasher: impl Fn(&T) -> u64) -> Bucket<T> { | 
|---|
| 1053 | unsafe { | 
|---|
| 1054 | // SAFETY: | 
|---|
| 1055 | // 1. The [`RawTableInner`] must already have properly initialized control bytes since | 
|---|
| 1056 | //    we will never expose `RawTable::new_uninitialized` in a public API. | 
|---|
| 1057 | // | 
|---|
| 1058 | // 2. We reserve additional space (if necessary) right after calling this function. | 
|---|
| 1059 | let mut slot = self.table.find_insert_slot(hash); | 
|---|
| 1060 |  | 
|---|
| 1061 | // We can avoid growing the table once we have reached our load factor if we are replacing | 
|---|
| 1062 | // a tombstone. This works since the number of EMPTY slots does not change in this case. | 
|---|
| 1063 | // | 
|---|
| 1064 | // SAFETY: The function is guaranteed to return [`InsertSlot`] that contains an index | 
|---|
| 1065 | // in the range `0..=self.buckets()`. | 
|---|
| 1066 | let old_ctrl = *self.table.ctrl(slot.index); | 
|---|
| 1067 | if unlikely(self.table.growth_left == 0 && old_ctrl.special_is_empty()) { | 
|---|
| 1068 | self.reserve(1, hasher); | 
|---|
| 1069 | // SAFETY: We know for sure that `RawTableInner` has control bytes | 
|---|
| 1070 | // initialized and that there is extra space in the table. | 
|---|
| 1071 | slot = self.table.find_insert_slot(hash); | 
|---|
| 1072 | } | 
|---|
| 1073 |  | 
|---|
| 1074 | self.insert_in_slot(hash, slot, value) | 
|---|
| 1075 | } | 
|---|
| 1076 | } | 
|---|
| 1077 |  | 
|---|
| 1078 | /// Inserts a new element into the table, and returns a mutable reference to it. | 
|---|
| 1079 | /// | 
|---|
| 1080 | /// This does not check if the given element already exists in the table. | 
|---|
| 1081 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 1082 | pub fn insert_entry(&mut self, hash: u64, value: T, hasher: impl Fn(&T) -> u64) -> &mut T { | 
|---|
| 1083 | unsafe { self.insert(hash, value, hasher).as_mut() } | 
|---|
| 1084 | } | 
|---|
| 1085 |  | 
|---|
| 1086 | /// Inserts a new element into the table, without growing the table. | 
|---|
| 1087 | /// | 
|---|
| 1088 | /// There must be enough space in the table to insert the new element. | 
|---|
| 1089 | /// | 
|---|
| 1090 | /// This does not check if the given element already exists in the table. | 
|---|
| 1091 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 1092 | #[ cfg(feature = "rustc-internal-api")] | 
|---|
| 1093 | pub unsafe fn insert_no_grow(&mut self, hash: u64, value: T) -> Bucket<T> { | 
|---|
| 1094 | let (index, old_ctrl) = self.table.prepare_insert_slot(hash); | 
|---|
| 1095 | let bucket = self.table.bucket(index); | 
|---|
| 1096 |  | 
|---|
| 1097 | // If we are replacing a DELETED entry then we don't need to update | 
|---|
| 1098 | // the load counter. | 
|---|
| 1099 | self.table.growth_left -= old_ctrl.special_is_empty() as usize; | 
|---|
| 1100 |  | 
|---|
| 1101 | bucket.write(value); | 
|---|
| 1102 | self.table.items += 1; | 
|---|
| 1103 | bucket | 
|---|
| 1104 | } | 
|---|
| 1105 |  | 
|---|
| 1106 | /// Temporary removes a bucket, applying the given function to the removed | 
|---|
| 1107 | /// element and optionally put back the returned value in the same bucket. | 
|---|
| 1108 | /// | 
|---|
| 1109 | /// Returns `true` if the bucket still contains an element | 
|---|
| 1110 | /// | 
|---|
| 1111 | /// This does not check if the given bucket is actually occupied. | 
|---|
| 1112 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 1113 | pub unsafe fn replace_bucket_with<F>(&mut self, bucket: Bucket<T>, f: F) -> bool | 
|---|
| 1114 | where | 
|---|
| 1115 | F: FnOnce(T) -> Option<T>, | 
|---|
| 1116 | { | 
|---|
| 1117 | let index = self.bucket_index(&bucket); | 
|---|
| 1118 | let old_ctrl = *self.table.ctrl(index); | 
|---|
| 1119 | debug_assert!(self.is_bucket_full(index)); | 
|---|
| 1120 | let old_growth_left = self.table.growth_left; | 
|---|
| 1121 | let item = self.remove(bucket).0; | 
|---|
| 1122 | if let Some(new_item) = f(item) { | 
|---|
| 1123 | self.table.growth_left = old_growth_left; | 
|---|
| 1124 | self.table.set_ctrl(index, old_ctrl); | 
|---|
| 1125 | self.table.items += 1; | 
|---|
| 1126 | self.bucket(index).write(new_item); | 
|---|
| 1127 | true | 
|---|
| 1128 | } else { | 
|---|
| 1129 | false | 
|---|
| 1130 | } | 
|---|
| 1131 | } | 
|---|
| 1132 |  | 
|---|
| 1133 | /// Searches for an element in the table. If the element is not found, | 
|---|
| 1134 | /// returns `Err` with the position of a slot where an element with the | 
|---|
| 1135 | /// same hash could be inserted. | 
|---|
| 1136 | /// | 
|---|
| 1137 | /// This function may resize the table if additional space is required for | 
|---|
| 1138 | /// inserting an element. | 
|---|
| 1139 | #[ inline] | 
|---|
| 1140 | pub fn find_or_find_insert_slot( | 
|---|
| 1141 | &mut self, | 
|---|
| 1142 | hash: u64, | 
|---|
| 1143 | mut eq: impl FnMut(&T) -> bool, | 
|---|
| 1144 | hasher: impl Fn(&T) -> u64, | 
|---|
| 1145 | ) -> Result<Bucket<T>, InsertSlot> { | 
|---|
| 1146 | self.reserve(1, hasher); | 
|---|
| 1147 |  | 
|---|
| 1148 | unsafe { | 
|---|
| 1149 | // SAFETY: | 
|---|
| 1150 | // 1. We know for sure that there is at least one empty `bucket` in the table. | 
|---|
| 1151 | // 2. The [`RawTableInner`] must already have properly initialized control bytes since we will | 
|---|
| 1152 | //    never expose `RawTable::new_uninitialized` in a public API. | 
|---|
| 1153 | // 3. The `find_or_find_insert_slot_inner` function returns the `index` of only the full bucket, | 
|---|
| 1154 | //    which is in the range `0..self.buckets()` (since there is at least one empty `bucket` in | 
|---|
| 1155 | //    the table), so calling `self.bucket(index)` and `Bucket::as_ref` is safe. | 
|---|
| 1156 | match self | 
|---|
| 1157 | .table | 
|---|
| 1158 | .find_or_find_insert_slot_inner(hash, &mut |index| eq(self.bucket(index).as_ref())) | 
|---|
| 1159 | { | 
|---|
| 1160 | // SAFETY: See explanation above. | 
|---|
| 1161 | Ok(index) => Ok(self.bucket(index)), | 
|---|
| 1162 | Err(slot) => Err(slot), | 
|---|
| 1163 | } | 
|---|
| 1164 | } | 
|---|
| 1165 | } | 
|---|
| 1166 |  | 
|---|
| 1167 | /// Inserts a new element into the table in the given slot, and returns its | 
|---|
| 1168 | /// raw bucket. | 
|---|
| 1169 | /// | 
|---|
| 1170 | /// # Safety | 
|---|
| 1171 | /// | 
|---|
| 1172 | /// `slot` must point to a slot previously returned by | 
|---|
| 1173 | /// `find_or_find_insert_slot`, and no mutation of the table must have | 
|---|
| 1174 | /// occurred since that call. | 
|---|
| 1175 | #[ inline] | 
|---|
| 1176 | pub unsafe fn insert_in_slot(&mut self, hash: u64, slot: InsertSlot, value: T) -> Bucket<T> { | 
|---|
| 1177 | let old_ctrl = *self.table.ctrl(slot.index); | 
|---|
| 1178 | self.table.record_item_insert_at(slot.index, old_ctrl, hash); | 
|---|
| 1179 |  | 
|---|
| 1180 | let bucket = self.bucket(slot.index); | 
|---|
| 1181 | bucket.write(value); | 
|---|
| 1182 | bucket | 
|---|
| 1183 | } | 
|---|
| 1184 |  | 
|---|
| 1185 | /// Searches for an element in the table. | 
|---|
| 1186 | #[ inline] | 
|---|
| 1187 | pub fn find(&self, hash: u64, mut eq: impl FnMut(&T) -> bool) -> Option<Bucket<T>> { | 
|---|
| 1188 | unsafe { | 
|---|
| 1189 | // SAFETY: | 
|---|
| 1190 | // 1. The [`RawTableInner`] must already have properly initialized control bytes since we | 
|---|
| 1191 | //    will never expose `RawTable::new_uninitialized` in a public API. | 
|---|
| 1192 | // 1. The `find_inner` function returns the `index` of only the full bucket, which is in | 
|---|
| 1193 | //    the range `0..self.buckets()`, so calling `self.bucket(index)` and `Bucket::as_ref` | 
|---|
| 1194 | //    is safe. | 
|---|
| 1195 | let result = self | 
|---|
| 1196 | .table | 
|---|
| 1197 | .find_inner(hash, &mut |index| eq(self.bucket(index).as_ref())); | 
|---|
| 1198 |  | 
|---|
| 1199 | // Avoid `Option::map` because it bloats LLVM IR. | 
|---|
| 1200 | match result { | 
|---|
| 1201 | // SAFETY: See explanation above. | 
|---|
| 1202 | Some(index) => Some(self.bucket(index)), | 
|---|
| 1203 | None => None, | 
|---|
| 1204 | } | 
|---|
| 1205 | } | 
|---|
| 1206 | } | 
|---|
| 1207 |  | 
|---|
| 1208 | /// Gets a reference to an element in the table. | 
|---|
| 1209 | #[ inline] | 
|---|
| 1210 | pub fn get(&self, hash: u64, eq: impl FnMut(&T) -> bool) -> Option<&T> { | 
|---|
| 1211 | // Avoid `Option::map` because it bloats LLVM IR. | 
|---|
| 1212 | match self.find(hash, eq) { | 
|---|
| 1213 | Some(bucket) => Some(unsafe { bucket.as_ref() }), | 
|---|
| 1214 | None => None, | 
|---|
| 1215 | } | 
|---|
| 1216 | } | 
|---|
| 1217 |  | 
|---|
| 1218 | /// Gets a mutable reference to an element in the table. | 
|---|
| 1219 | #[ inline] | 
|---|
| 1220 | pub fn get_mut(&mut self, hash: u64, eq: impl FnMut(&T) -> bool) -> Option<&mut T> { | 
|---|
| 1221 | // Avoid `Option::map` because it bloats LLVM IR. | 
|---|
| 1222 | match self.find(hash, eq) { | 
|---|
| 1223 | Some(bucket) => Some(unsafe { bucket.as_mut() }), | 
|---|
| 1224 | None => None, | 
|---|
| 1225 | } | 
|---|
| 1226 | } | 
|---|
| 1227 |  | 
|---|
| 1228 | /// Attempts to get mutable references to `N` entries in the table at once. | 
|---|
| 1229 | /// | 
|---|
| 1230 | /// Returns an array of length `N` with the results of each query. | 
|---|
| 1231 | /// | 
|---|
| 1232 | /// At most one mutable reference will be returned to any entry. `None` will be returned if any | 
|---|
| 1233 | /// of the hashes are duplicates. `None` will be returned if the hash is not found. | 
|---|
| 1234 | /// | 
|---|
| 1235 | /// The `eq` argument should be a closure such that `eq(i, k)` returns true if `k` is equal to | 
|---|
| 1236 | /// the `i`th key to be looked up. | 
|---|
| 1237 | pub fn get_many_mut<const N: usize>( | 
|---|
| 1238 | &mut self, | 
|---|
| 1239 | hashes: [u64; N], | 
|---|
| 1240 | eq: impl FnMut(usize, &T) -> bool, | 
|---|
| 1241 | ) -> [Option<&'_ mut T>; N] { | 
|---|
| 1242 | unsafe { | 
|---|
| 1243 | let ptrs = self.get_many_mut_pointers(hashes, eq); | 
|---|
| 1244 |  | 
|---|
| 1245 | for (i, cur) in ptrs.iter().enumerate() { | 
|---|
| 1246 | if cur.is_some() && ptrs[..i].contains(cur) { | 
|---|
| 1247 | panic!( "duplicate keys found"); | 
|---|
| 1248 | } | 
|---|
| 1249 | } | 
|---|
| 1250 | // All bucket are distinct from all previous buckets so we're clear to return the result | 
|---|
| 1251 | // of the lookup. | 
|---|
| 1252 |  | 
|---|
| 1253 | ptrs.map(|ptr| ptr.map(|mut ptr| ptr.as_mut())) | 
|---|
| 1254 | } | 
|---|
| 1255 | } | 
|---|
| 1256 |  | 
|---|
| 1257 | pub unsafe fn get_many_unchecked_mut<const N: usize>( | 
|---|
| 1258 | &mut self, | 
|---|
| 1259 | hashes: [u64; N], | 
|---|
| 1260 | eq: impl FnMut(usize, &T) -> bool, | 
|---|
| 1261 | ) -> [Option<&'_ mut T>; N] { | 
|---|
| 1262 | let ptrs = self.get_many_mut_pointers(hashes, eq); | 
|---|
| 1263 | ptrs.map(|ptr| ptr.map(|mut ptr| ptr.as_mut())) | 
|---|
| 1264 | } | 
|---|
| 1265 |  | 
|---|
| 1266 | unsafe fn get_many_mut_pointers<const N: usize>( | 
|---|
| 1267 | &mut self, | 
|---|
| 1268 | hashes: [u64; N], | 
|---|
| 1269 | mut eq: impl FnMut(usize, &T) -> bool, | 
|---|
| 1270 | ) -> [Option<NonNull<T>>; N] { | 
|---|
| 1271 | array::from_fn(|i| { | 
|---|
| 1272 | self.find(hashes[i], |k| eq(i, k)) | 
|---|
| 1273 | .map(|cur| cur.as_non_null()) | 
|---|
| 1274 | }) | 
|---|
| 1275 | } | 
|---|
| 1276 |  | 
|---|
| 1277 | /// Returns the number of elements the map can hold without reallocating. | 
|---|
| 1278 | /// | 
|---|
| 1279 | /// This number is a lower bound; the table might be able to hold | 
|---|
| 1280 | /// more, but is guaranteed to be able to hold at least this many. | 
|---|
| 1281 | #[ inline] | 
|---|
| 1282 | pub fn capacity(&self) -> usize { | 
|---|
| 1283 | self.table.items + self.table.growth_left | 
|---|
| 1284 | } | 
|---|
| 1285 |  | 
|---|
| 1286 | /// Returns the number of elements in the table. | 
|---|
| 1287 | #[ inline] | 
|---|
| 1288 | pub fn len(&self) -> usize { | 
|---|
| 1289 | self.table.items | 
|---|
| 1290 | } | 
|---|
| 1291 |  | 
|---|
| 1292 | /// Returns `true` if the table contains no elements. | 
|---|
| 1293 | #[ inline] | 
|---|
| 1294 | pub fn is_empty(&self) -> bool { | 
|---|
| 1295 | self.len() == 0 | 
|---|
| 1296 | } | 
|---|
| 1297 |  | 
|---|
| 1298 | /// Returns the number of buckets in the table. | 
|---|
| 1299 | #[ inline] | 
|---|
| 1300 | pub fn buckets(&self) -> usize { | 
|---|
| 1301 | self.table.bucket_mask + 1 | 
|---|
| 1302 | } | 
|---|
| 1303 |  | 
|---|
| 1304 | /// Checks whether the bucket at `index` is full. | 
|---|
| 1305 | /// | 
|---|
| 1306 | /// # Safety | 
|---|
| 1307 | /// | 
|---|
| 1308 | /// The caller must ensure `index` is less than the number of buckets. | 
|---|
| 1309 | #[ inline] | 
|---|
| 1310 | pub unsafe fn is_bucket_full(&self, index: usize) -> bool { | 
|---|
| 1311 | self.table.is_bucket_full(index) | 
|---|
| 1312 | } | 
|---|
| 1313 |  | 
|---|
| 1314 | /// Returns an iterator over every element in the table. It is up to | 
|---|
| 1315 | /// the caller to ensure that the `RawTable` outlives the `RawIter`. | 
|---|
| 1316 | /// Because we cannot make the `next` method unsafe on the `RawIter` | 
|---|
| 1317 | /// struct, we have to make the `iter` method unsafe. | 
|---|
| 1318 | #[ inline] | 
|---|
| 1319 | pub unsafe fn iter(&self) -> RawIter<T> { | 
|---|
| 1320 | // SAFETY: | 
|---|
| 1321 | // 1. The caller must uphold the safety contract for `iter` method. | 
|---|
| 1322 | // 2. The [`RawTableInner`] must already have properly initialized control bytes since | 
|---|
| 1323 | //    we will never expose RawTable::new_uninitialized in a public API. | 
|---|
| 1324 | self.table.iter() | 
|---|
| 1325 | } | 
|---|
| 1326 |  | 
|---|
| 1327 | /// Returns an iterator over occupied buckets that could match a given hash. | 
|---|
| 1328 | /// | 
|---|
| 1329 | /// `RawTable` only stores 7 bits of the hash value, so this iterator may | 
|---|
| 1330 | /// return items that have a hash value different than the one provided. You | 
|---|
| 1331 | /// should always validate the returned values before using them. | 
|---|
| 1332 | /// | 
|---|
| 1333 | /// It is up to the caller to ensure that the `RawTable` outlives the | 
|---|
| 1334 | /// `RawIterHash`. Because we cannot make the `next` method unsafe on the | 
|---|
| 1335 | /// `RawIterHash` struct, we have to make the `iter_hash` method unsafe. | 
|---|
| 1336 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 1337 | pub unsafe fn iter_hash(&self, hash: u64) -> RawIterHash<T> { | 
|---|
| 1338 | RawIterHash::new(self, hash) | 
|---|
| 1339 | } | 
|---|
| 1340 |  | 
|---|
| 1341 | /// Returns an iterator which removes all elements from the table without | 
|---|
| 1342 | /// freeing the memory. | 
|---|
| 1343 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 1344 | pub fn drain(&mut self) -> RawDrain<'_, T, A> { | 
|---|
| 1345 | unsafe { | 
|---|
| 1346 | let iter = self.iter(); | 
|---|
| 1347 | self.drain_iter_from(iter) | 
|---|
| 1348 | } | 
|---|
| 1349 | } | 
|---|
| 1350 |  | 
|---|
| 1351 | /// Returns an iterator which removes all elements from the table without | 
|---|
| 1352 | /// freeing the memory. | 
|---|
| 1353 | /// | 
|---|
| 1354 | /// Iteration starts at the provided iterator's current location. | 
|---|
| 1355 | /// | 
|---|
| 1356 | /// It is up to the caller to ensure that the iterator is valid for this | 
|---|
| 1357 | /// `RawTable` and covers all items that remain in the table. | 
|---|
| 1358 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 1359 | pub unsafe fn drain_iter_from(&mut self, iter: RawIter<T>) -> RawDrain<'_, T, A> { | 
|---|
| 1360 | debug_assert_eq!(iter.len(), self.len()); | 
|---|
| 1361 | RawDrain { | 
|---|
| 1362 | iter, | 
|---|
| 1363 | table: mem::replace(&mut self.table, RawTableInner::NEW), | 
|---|
| 1364 | orig_table: NonNull::from(&mut self.table), | 
|---|
| 1365 | marker: PhantomData, | 
|---|
| 1366 | } | 
|---|
| 1367 | } | 
|---|
| 1368 |  | 
|---|
| 1369 | /// Returns an iterator which consumes all elements from the table. | 
|---|
| 1370 | /// | 
|---|
| 1371 | /// Iteration starts at the provided iterator's current location. | 
|---|
| 1372 | /// | 
|---|
| 1373 | /// It is up to the caller to ensure that the iterator is valid for this | 
|---|
| 1374 | /// `RawTable` and covers all items that remain in the table. | 
|---|
| 1375 | pub unsafe fn into_iter_from(self, iter: RawIter<T>) -> RawIntoIter<T, A> { | 
|---|
| 1376 | debug_assert_eq!(iter.len(), self.len()); | 
|---|
| 1377 |  | 
|---|
| 1378 | let allocation = self.into_allocation(); | 
|---|
| 1379 | RawIntoIter { | 
|---|
| 1380 | iter, | 
|---|
| 1381 | allocation, | 
|---|
| 1382 | marker: PhantomData, | 
|---|
| 1383 | } | 
|---|
| 1384 | } | 
|---|
| 1385 |  | 
|---|
| 1386 | /// Converts the table into a raw allocation. The contents of the table | 
|---|
| 1387 | /// should be dropped using a `RawIter` before freeing the allocation. | 
|---|
| 1388 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 1389 | pub(crate) fn into_allocation(self) -> Option<(NonNull<u8>, Layout, A)> { | 
|---|
| 1390 | let alloc = if self.table.is_empty_singleton() { | 
|---|
| 1391 | None | 
|---|
| 1392 | } else { | 
|---|
| 1393 | // Avoid `Option::unwrap_or_else` because it bloats LLVM IR. | 
|---|
| 1394 | let (layout, ctrl_offset) = | 
|---|
| 1395 | match Self::TABLE_LAYOUT.calculate_layout_for(self.table.buckets()) { | 
|---|
| 1396 | Some(lco) => lco, | 
|---|
| 1397 | None => unsafe { hint::unreachable_unchecked() }, | 
|---|
| 1398 | }; | 
|---|
| 1399 | Some(( | 
|---|
| 1400 | unsafe { NonNull::new_unchecked(self.table.ctrl.as_ptr().sub(ctrl_offset).cast()) }, | 
|---|
| 1401 | layout, | 
|---|
| 1402 | unsafe { ptr::read(&self.alloc) }, | 
|---|
| 1403 | )) | 
|---|
| 1404 | }; | 
|---|
| 1405 | mem::forget(self); | 
|---|
| 1406 | alloc | 
|---|
| 1407 | } | 
|---|
| 1408 | } | 
|---|
| 1409 |  | 
|---|
| 1410 | unsafe impl<T, A: Allocator> Send for RawTable<T, A> | 
|---|
| 1411 | where | 
|---|
| 1412 | T: Send, | 
|---|
| 1413 | A: Send, | 
|---|
| 1414 | { | 
|---|
| 1415 | } | 
|---|
| 1416 | unsafe impl<T, A: Allocator> Sync for RawTable<T, A> | 
|---|
| 1417 | where | 
|---|
| 1418 | T: Sync, | 
|---|
| 1419 | A: Sync, | 
|---|
| 1420 | { | 
|---|
| 1421 | } | 
|---|
| 1422 |  | 
|---|
| 1423 | impl RawTableInner { | 
|---|
| 1424 | const NEW: Self = RawTableInner::new(); | 
|---|
| 1425 |  | 
|---|
| 1426 | /// Creates a new empty hash table without allocating any memory. | 
|---|
| 1427 | /// | 
|---|
| 1428 | /// In effect this returns a table with exactly 1 bucket. However we can | 
|---|
| 1429 | /// leave the data pointer dangling since that bucket is never accessed | 
|---|
| 1430 | /// due to our load factor forcing us to always have at least 1 free bucket. | 
|---|
| 1431 | #[ inline] | 
|---|
| 1432 | const fn new() -> Self { | 
|---|
| 1433 | Self { | 
|---|
| 1434 | // Be careful to cast the entire slice to a raw pointer. | 
|---|
| 1435 | ctrl: unsafe { | 
|---|
| 1436 | NonNull::new_unchecked(ptr:Group::static_empty().as_ptr().cast_mut().cast()) | 
|---|
| 1437 | }, | 
|---|
| 1438 | bucket_mask: 0, | 
|---|
| 1439 | items: 0, | 
|---|
| 1440 | growth_left: 0, | 
|---|
| 1441 | } | 
|---|
| 1442 | } | 
|---|
| 1443 | } | 
|---|
| 1444 |  | 
|---|
| 1445 | impl RawTableInner { | 
|---|
| 1446 | /// Allocates a new [`RawTableInner`] with the given number of buckets. | 
|---|
| 1447 | /// The control bytes and buckets are left uninitialized. | 
|---|
| 1448 | /// | 
|---|
| 1449 | /// # Safety | 
|---|
| 1450 | /// | 
|---|
| 1451 | /// The caller of this function must ensure that the `buckets` is power of two | 
|---|
| 1452 | /// and also initialize all control bytes of the length `self.bucket_mask + 1 + | 
|---|
| 1453 | /// Group::WIDTH` with the [`Tag::EMPTY`] bytes. | 
|---|
| 1454 | /// | 
|---|
| 1455 | /// See also [`Allocator`] API for other safety concerns. | 
|---|
| 1456 | /// | 
|---|
| 1457 | /// [`Allocator`]: https://doc.rust-lang.org/alloc/alloc/trait.Allocator.html | 
|---|
| 1458 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 1459 | unsafe fn new_uninitialized<A>( | 
|---|
| 1460 | alloc: &A, | 
|---|
| 1461 | table_layout: TableLayout, | 
|---|
| 1462 | buckets: usize, | 
|---|
| 1463 | fallibility: Fallibility, | 
|---|
| 1464 | ) -> Result<Self, TryReserveError> | 
|---|
| 1465 | where | 
|---|
| 1466 | A: Allocator, | 
|---|
| 1467 | { | 
|---|
| 1468 | debug_assert!(buckets.is_power_of_two()); | 
|---|
| 1469 |  | 
|---|
| 1470 | // Avoid `Option::ok_or_else` because it bloats LLVM IR. | 
|---|
| 1471 | let (layout, ctrl_offset) = match table_layout.calculate_layout_for(buckets) { | 
|---|
| 1472 | Some(lco) => lco, | 
|---|
| 1473 | None => return Err(fallibility.capacity_overflow()), | 
|---|
| 1474 | }; | 
|---|
| 1475 |  | 
|---|
| 1476 | let ptr: NonNull<u8> = match do_alloc(alloc, layout) { | 
|---|
| 1477 | Ok(block) => block.cast(), | 
|---|
| 1478 | Err(_) => return Err(fallibility.alloc_err(layout)), | 
|---|
| 1479 | }; | 
|---|
| 1480 |  | 
|---|
| 1481 | // SAFETY: null pointer will be caught in above check | 
|---|
| 1482 | let ctrl = NonNull::new_unchecked(ptr.as_ptr().add(ctrl_offset)); | 
|---|
| 1483 | Ok(Self { | 
|---|
| 1484 | ctrl, | 
|---|
| 1485 | bucket_mask: buckets - 1, | 
|---|
| 1486 | items: 0, | 
|---|
| 1487 | growth_left: bucket_mask_to_capacity(buckets - 1), | 
|---|
| 1488 | }) | 
|---|
| 1489 | } | 
|---|
| 1490 |  | 
|---|
| 1491 | /// Attempts to allocate a new [`RawTableInner`] with at least enough | 
|---|
| 1492 | /// capacity for inserting the given number of elements without reallocating. | 
|---|
| 1493 | /// | 
|---|
| 1494 | /// All the control bytes are initialized with the [`Tag::EMPTY`] bytes. | 
|---|
| 1495 | #[ inline] | 
|---|
| 1496 | fn fallible_with_capacity<A>( | 
|---|
| 1497 | alloc: &A, | 
|---|
| 1498 | table_layout: TableLayout, | 
|---|
| 1499 | capacity: usize, | 
|---|
| 1500 | fallibility: Fallibility, | 
|---|
| 1501 | ) -> Result<Self, TryReserveError> | 
|---|
| 1502 | where | 
|---|
| 1503 | A: Allocator, | 
|---|
| 1504 | { | 
|---|
| 1505 | if capacity == 0 { | 
|---|
| 1506 | Ok(Self::NEW) | 
|---|
| 1507 | } else { | 
|---|
| 1508 | // SAFETY: We checked that we could successfully allocate the new table, and then | 
|---|
| 1509 | // initialized all control bytes with the constant `Tag::EMPTY` byte. | 
|---|
| 1510 | unsafe { | 
|---|
| 1511 | let buckets = capacity_to_buckets(capacity, table_layout) | 
|---|
| 1512 | .ok_or_else(|| fallibility.capacity_overflow())?; | 
|---|
| 1513 |  | 
|---|
| 1514 | let mut result = | 
|---|
| 1515 | Self::new_uninitialized(alloc, table_layout, buckets, fallibility)?; | 
|---|
| 1516 | // SAFETY: We checked that the table is allocated and therefore the table already has | 
|---|
| 1517 | // `self.bucket_mask + 1 + Group::WIDTH` number of control bytes (see TableLayout::calculate_layout_for) | 
|---|
| 1518 | // so writing `self.num_ctrl_bytes() == bucket_mask + 1 + Group::WIDTH` bytes is safe. | 
|---|
| 1519 | result.ctrl_slice().fill_empty(); | 
|---|
| 1520 |  | 
|---|
| 1521 | Ok(result) | 
|---|
| 1522 | } | 
|---|
| 1523 | } | 
|---|
| 1524 | } | 
|---|
| 1525 |  | 
|---|
| 1526 | /// Allocates a new [`RawTableInner`] with at least enough capacity for inserting | 
|---|
| 1527 | /// the given number of elements without reallocating. | 
|---|
| 1528 | /// | 
|---|
| 1529 | /// Panics if the new capacity exceeds [`isize::MAX`] bytes and [`abort`] the program | 
|---|
| 1530 | /// in case of allocation error. Use [`fallible_with_capacity`] instead if you want to | 
|---|
| 1531 | /// handle memory allocation failure. | 
|---|
| 1532 | /// | 
|---|
| 1533 | /// All the control bytes are initialized with the [`Tag::EMPTY`] bytes. | 
|---|
| 1534 | /// | 
|---|
| 1535 | /// [`fallible_with_capacity`]: RawTableInner::fallible_with_capacity | 
|---|
| 1536 | /// [`abort`]: https://doc.rust-lang.org/alloc/alloc/fn.handle_alloc_error.html | 
|---|
| 1537 | fn with_capacity<A>(alloc: &A, table_layout: TableLayout, capacity: usize) -> Self | 
|---|
| 1538 | where | 
|---|
| 1539 | A: Allocator, | 
|---|
| 1540 | { | 
|---|
| 1541 | // Avoid `Result::unwrap_or_else` because it bloats LLVM IR. | 
|---|
| 1542 | match Self::fallible_with_capacity(alloc, table_layout, capacity, Fallibility::Infallible) { | 
|---|
| 1543 | Ok(table_inner) => table_inner, | 
|---|
| 1544 | // SAFETY: All allocation errors will be caught inside `RawTableInner::new_uninitialized`. | 
|---|
| 1545 | Err(_) => unsafe { hint::unreachable_unchecked() }, | 
|---|
| 1546 | } | 
|---|
| 1547 | } | 
|---|
| 1548 |  | 
|---|
| 1549 | /// Fixes up an insertion slot returned by the [`RawTableInner::find_insert_slot_in_group`] method. | 
|---|
| 1550 | /// | 
|---|
| 1551 | /// In tables smaller than the group width (`self.buckets() < Group::WIDTH`), trailing control | 
|---|
| 1552 | /// bytes outside the range of the table are filled with [`Tag::EMPTY`] entries. These will unfortunately | 
|---|
| 1553 | /// trigger a match of [`RawTableInner::find_insert_slot_in_group`] function. This is because | 
|---|
| 1554 | /// the `Some(bit)` returned by `group.match_empty_or_deleted().lowest_set_bit()` after masking | 
|---|
| 1555 | /// (`(probe_seq.pos + bit) & self.bucket_mask`) may point to a full bucket that is already occupied. | 
|---|
| 1556 | /// We detect this situation here and perform a second scan starting at the beginning of the table. | 
|---|
| 1557 | /// This second scan is guaranteed to find an empty slot (due to the load factor) before hitting the | 
|---|
| 1558 | /// trailing control bytes (containing [`Tag::EMPTY`] bytes). | 
|---|
| 1559 | /// | 
|---|
| 1560 | /// If this function is called correctly, it is guaranteed to return [`InsertSlot`] with an | 
|---|
| 1561 | /// index of an empty or deleted bucket in the range `0..self.buckets()` (see `Warning` and | 
|---|
| 1562 | /// `Safety`). | 
|---|
| 1563 | /// | 
|---|
| 1564 | /// # Warning | 
|---|
| 1565 | /// | 
|---|
| 1566 | /// The table must have at least 1 empty or deleted `bucket`, otherwise if the table is less than | 
|---|
| 1567 | /// the group width (`self.buckets() < Group::WIDTH`) this function returns an index outside of the | 
|---|
| 1568 | /// table indices range `0..self.buckets()` (`0..=self.bucket_mask`). Attempt to write data at that | 
|---|
| 1569 | /// index will cause immediate [`undefined behavior`]. | 
|---|
| 1570 | /// | 
|---|
| 1571 | /// # Safety | 
|---|
| 1572 | /// | 
|---|
| 1573 | /// The safety rules are directly derived from the safety rules for [`RawTableInner::ctrl`] method. | 
|---|
| 1574 | /// Thus, in order to uphold those safety contracts, as well as for the correct logic of the work | 
|---|
| 1575 | /// of this crate, the following rules are necessary and sufficient: | 
|---|
| 1576 | /// | 
|---|
| 1577 | /// * The [`RawTableInner`] must have properly initialized control bytes otherwise calling this | 
|---|
| 1578 | ///   function results in [`undefined behavior`]. | 
|---|
| 1579 | /// | 
|---|
| 1580 | /// * This function must only be used on insertion slots found by [`RawTableInner::find_insert_slot_in_group`] | 
|---|
| 1581 | ///   (after the `find_insert_slot_in_group` function, but before insertion into the table). | 
|---|
| 1582 | /// | 
|---|
| 1583 | /// * The `index` must not be greater than the `self.bucket_mask`, i.e. `(index + 1) <= self.buckets()` | 
|---|
| 1584 | ///   (this one is provided by the [`RawTableInner::find_insert_slot_in_group`] function). | 
|---|
| 1585 | /// | 
|---|
| 1586 | /// Calling this function with an index not provided by [`RawTableInner::find_insert_slot_in_group`] | 
|---|
| 1587 | /// may result in [`undefined behavior`] even if the index satisfies the safety rules of the | 
|---|
| 1588 | /// [`RawTableInner::ctrl`] function (`index < self.bucket_mask + 1 + Group::WIDTH`). | 
|---|
| 1589 | /// | 
|---|
| 1590 | /// [`RawTableInner::ctrl`]: RawTableInner::ctrl | 
|---|
| 1591 | /// [`RawTableInner::find_insert_slot_in_group`]: RawTableInner::find_insert_slot_in_group | 
|---|
| 1592 | /// [`undefined behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 1593 | #[ inline] | 
|---|
| 1594 | unsafe fn fix_insert_slot(&self, mut index: usize) -> InsertSlot { | 
|---|
| 1595 | // SAFETY: The caller of this function ensures that `index` is in the range `0..=self.bucket_mask`. | 
|---|
| 1596 | if unlikely(self.is_bucket_full(index)) { | 
|---|
| 1597 | debug_assert!(self.bucket_mask < Group::WIDTH); | 
|---|
| 1598 | // SAFETY: | 
|---|
| 1599 | // | 
|---|
| 1600 | // * Since the caller of this function ensures that the control bytes are properly | 
|---|
| 1601 | //   initialized and `ptr = self.ctrl(0)` points to the start of the array of control | 
|---|
| 1602 | //   bytes, therefore: `ctrl` is valid for reads, properly aligned to `Group::WIDTH` | 
|---|
| 1603 | //   and points to the properly initialized control bytes (see also | 
|---|
| 1604 | //   `TableLayout::calculate_layout_for` and `ptr::read`); | 
|---|
| 1605 | // | 
|---|
| 1606 | // * Because the caller of this function ensures that the index was provided by the | 
|---|
| 1607 | //   `self.find_insert_slot_in_group()` function, so for for tables larger than the | 
|---|
| 1608 | //   group width (self.buckets() >= Group::WIDTH), we will never end up in the given | 
|---|
| 1609 | //   branch, since `(probe_seq.pos + bit) & self.bucket_mask` in `find_insert_slot_in_group` | 
|---|
| 1610 | //   cannot return a full bucket index. For tables smaller than the group width, calling | 
|---|
| 1611 | //   the `unwrap_unchecked` function is also safe, as the trailing control bytes outside | 
|---|
| 1612 | //   the range of the table are filled with EMPTY bytes (and we know for sure that there | 
|---|
| 1613 | //   is at least one FULL bucket), so this second scan either finds an empty slot (due to | 
|---|
| 1614 | //   the load factor) or hits the trailing control bytes (containing EMPTY). | 
|---|
| 1615 | index = Group::load_aligned(self.ctrl(0)) | 
|---|
| 1616 | .match_empty_or_deleted() | 
|---|
| 1617 | .lowest_set_bit() | 
|---|
| 1618 | .unwrap_unchecked(); | 
|---|
| 1619 | } | 
|---|
| 1620 | InsertSlot { index } | 
|---|
| 1621 | } | 
|---|
| 1622 |  | 
|---|
| 1623 | /// Finds the position to insert something in a group. | 
|---|
| 1624 | /// | 
|---|
| 1625 | /// **This may have false positives and must be fixed up with `fix_insert_slot` | 
|---|
| 1626 | /// before it's used.** | 
|---|
| 1627 | /// | 
|---|
| 1628 | /// The function is guaranteed to return the index of an empty or deleted [`Bucket`] | 
|---|
| 1629 | /// in the range `0..self.buckets()` (`0..=self.bucket_mask`). | 
|---|
| 1630 | #[ inline] | 
|---|
| 1631 | fn find_insert_slot_in_group(&self, group: &Group, probe_seq: &ProbeSeq) -> Option<usize> { | 
|---|
| 1632 | let bit = group.match_empty_or_deleted().lowest_set_bit(); | 
|---|
| 1633 |  | 
|---|
| 1634 | if likely(bit.is_some()) { | 
|---|
| 1635 | // This is the same as `(probe_seq.pos + bit) % self.buckets()` because the number | 
|---|
| 1636 | // of buckets is a power of two, and `self.bucket_mask = self.buckets() - 1`. | 
|---|
| 1637 | Some((probe_seq.pos + bit.unwrap()) & self.bucket_mask) | 
|---|
| 1638 | } else { | 
|---|
| 1639 | None | 
|---|
| 1640 | } | 
|---|
| 1641 | } | 
|---|
| 1642 |  | 
|---|
| 1643 | /// Searches for an element in the table, or a potential slot where that element could | 
|---|
| 1644 | /// be inserted (an empty or deleted [`Bucket`] index). | 
|---|
| 1645 | /// | 
|---|
| 1646 | /// This uses dynamic dispatch to reduce the amount of code generated, but that is | 
|---|
| 1647 | /// eliminated by LLVM optimizations. | 
|---|
| 1648 | /// | 
|---|
| 1649 | /// This function does not make any changes to the `data` part of the table, or any | 
|---|
| 1650 | /// changes to the `items` or `growth_left` field of the table. | 
|---|
| 1651 | /// | 
|---|
| 1652 | /// The table must have at least 1 empty or deleted `bucket`, otherwise, if the | 
|---|
| 1653 | /// `eq: &mut dyn FnMut(usize) -> bool` function does not return `true`, this function | 
|---|
| 1654 | /// will never return (will go into an infinite loop) for tables larger than the group | 
|---|
| 1655 | /// width, or return an index outside of the table indices range if the table is less | 
|---|
| 1656 | /// than the group width. | 
|---|
| 1657 | /// | 
|---|
| 1658 | /// This function is guaranteed to provide the `eq: &mut dyn FnMut(usize) -> bool` | 
|---|
| 1659 | /// function with only `FULL` buckets' indices and return the `index` of the found | 
|---|
| 1660 | /// element (as `Ok(index)`). If the element is not found and there is at least 1 | 
|---|
| 1661 | /// empty or deleted [`Bucket`] in the table, the function is guaranteed to return | 
|---|
| 1662 | /// [`InsertSlot`] with an index in the range `0..self.buckets()`, but in any case, | 
|---|
| 1663 | /// if this function returns [`InsertSlot`], it will contain an index in the range | 
|---|
| 1664 | /// `0..=self.buckets()`. | 
|---|
| 1665 | /// | 
|---|
| 1666 | /// # Safety | 
|---|
| 1667 | /// | 
|---|
| 1668 | /// The [`RawTableInner`] must have properly initialized control bytes otherwise calling | 
|---|
| 1669 | /// this function results in [`undefined behavior`]. | 
|---|
| 1670 | /// | 
|---|
| 1671 | /// Attempt to write data at the [`InsertSlot`] returned by this function when the table is | 
|---|
| 1672 | /// less than the group width and if there was not at least one empty or deleted bucket in | 
|---|
| 1673 | /// the table will cause immediate [`undefined behavior`]. This is because in this case the | 
|---|
| 1674 | /// function will return `self.bucket_mask + 1` as an index due to the trailing [`Tag::EMPTY`] | 
|---|
| 1675 | /// control bytes outside the table range. | 
|---|
| 1676 | /// | 
|---|
| 1677 | /// [`undefined behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 1678 | #[ inline] | 
|---|
| 1679 | unsafe fn find_or_find_insert_slot_inner( | 
|---|
| 1680 | &self, | 
|---|
| 1681 | hash: u64, | 
|---|
| 1682 | eq: &mut dyn FnMut(usize) -> bool, | 
|---|
| 1683 | ) -> Result<usize, InsertSlot> { | 
|---|
| 1684 | let mut insert_slot = None; | 
|---|
| 1685 |  | 
|---|
| 1686 | let tag_hash = Tag::full(hash); | 
|---|
| 1687 | let mut probe_seq = self.probe_seq(hash); | 
|---|
| 1688 |  | 
|---|
| 1689 | loop { | 
|---|
| 1690 | // SAFETY: | 
|---|
| 1691 | // * Caller of this function ensures that the control bytes are properly initialized. | 
|---|
| 1692 | // | 
|---|
| 1693 | // * `ProbeSeq.pos` cannot be greater than `self.bucket_mask = self.buckets() - 1` | 
|---|
| 1694 | //   of the table due to masking with `self.bucket_mask` and also because the number | 
|---|
| 1695 | //   of buckets is a power of two (see `self.probe_seq` function). | 
|---|
| 1696 | // | 
|---|
| 1697 | // * Even if `ProbeSeq.pos` returns `position == self.bucket_mask`, it is safe to | 
|---|
| 1698 | //   call `Group::load` due to the extended control bytes range, which is | 
|---|
| 1699 | //  `self.bucket_mask + 1 + Group::WIDTH` (in fact, this means that the last control | 
|---|
| 1700 | //   byte will never be read for the allocated table); | 
|---|
| 1701 | // | 
|---|
| 1702 | // * Also, even if `RawTableInner` is not already allocated, `ProbeSeq.pos` will | 
|---|
| 1703 | //   always return "0" (zero), so Group::load will read unaligned `Group::static_empty()` | 
|---|
| 1704 | //   bytes, which is safe (see RawTableInner::new). | 
|---|
| 1705 | let group = unsafe { Group::load(self.ctrl(probe_seq.pos)) }; | 
|---|
| 1706 |  | 
|---|
| 1707 | for bit in group.match_tag(tag_hash) { | 
|---|
| 1708 | let index = (probe_seq.pos + bit) & self.bucket_mask; | 
|---|
| 1709 |  | 
|---|
| 1710 | if likely(eq(index)) { | 
|---|
| 1711 | return Ok(index); | 
|---|
| 1712 | } | 
|---|
| 1713 | } | 
|---|
| 1714 |  | 
|---|
| 1715 | // We didn't find the element we were looking for in the group, try to get an | 
|---|
| 1716 | // insertion slot from the group if we don't have one yet. | 
|---|
| 1717 | if likely(insert_slot.is_none()) { | 
|---|
| 1718 | insert_slot = self.find_insert_slot_in_group(&group, &probe_seq); | 
|---|
| 1719 | } | 
|---|
| 1720 |  | 
|---|
| 1721 | if let Some(insert_slot) = insert_slot { | 
|---|
| 1722 | // Only stop the search if the group contains at least one empty element. | 
|---|
| 1723 | // Otherwise, the element that we are looking for might be in a following group. | 
|---|
| 1724 | if likely(group.match_empty().any_bit_set()) { | 
|---|
| 1725 | // We must have found a insert slot by now, since the current group contains at | 
|---|
| 1726 | // least one. For tables smaller than the group width, there will still be an | 
|---|
| 1727 | // empty element in the current (and only) group due to the load factor. | 
|---|
| 1728 | unsafe { | 
|---|
| 1729 | // SAFETY: | 
|---|
| 1730 | // * Caller of this function ensures that the control bytes are properly initialized. | 
|---|
| 1731 | // | 
|---|
| 1732 | // * We use this function with the slot / index found by `self.find_insert_slot_in_group` | 
|---|
| 1733 | return Err(self.fix_insert_slot(insert_slot)); | 
|---|
| 1734 | } | 
|---|
| 1735 | } | 
|---|
| 1736 | } | 
|---|
| 1737 |  | 
|---|
| 1738 | probe_seq.move_next(self.bucket_mask); | 
|---|
| 1739 | } | 
|---|
| 1740 | } | 
|---|
| 1741 |  | 
|---|
| 1742 | /// Searches for an empty or deleted bucket which is suitable for inserting a new | 
|---|
| 1743 | /// element and sets the hash for that slot. Returns an index of that slot and the | 
|---|
| 1744 | /// old control byte stored in the found index. | 
|---|
| 1745 | /// | 
|---|
| 1746 | /// This function does not check if the given element exists in the table. Also, | 
|---|
| 1747 | /// this function does not check if there is enough space in the table to insert | 
|---|
| 1748 | /// a new element. The caller of the function must make sure that the table has at | 
|---|
| 1749 | /// least 1 empty or deleted `bucket`, otherwise this function will never return | 
|---|
| 1750 | /// (will go into an infinite loop) for tables larger than the group width, or | 
|---|
| 1751 | /// return an index outside of the table indices range if the table is less than | 
|---|
| 1752 | /// the group width. | 
|---|
| 1753 | /// | 
|---|
| 1754 | /// If there is at least 1 empty or deleted `bucket` in the table, the function is | 
|---|
| 1755 | /// guaranteed to return an `index` in the range `0..self.buckets()`, but in any case, | 
|---|
| 1756 | /// if this function returns an `index` it will be in the range `0..=self.buckets()`. | 
|---|
| 1757 | /// | 
|---|
| 1758 | /// This function does not make any changes to the `data` parts of the table, | 
|---|
| 1759 | /// or any changes to the `items` or `growth_left` field of the table. | 
|---|
| 1760 | /// | 
|---|
| 1761 | /// # Safety | 
|---|
| 1762 | /// | 
|---|
| 1763 | /// The safety rules are directly derived from the safety rules for the | 
|---|
| 1764 | /// [`RawTableInner::set_ctrl_hash`] and [`RawTableInner::find_insert_slot`] methods. | 
|---|
| 1765 | /// Thus, in order to uphold the safety contracts for that methods, as well as for | 
|---|
| 1766 | /// the correct logic of the work of this crate, you must observe the following rules | 
|---|
| 1767 | /// when calling this function: | 
|---|
| 1768 | /// | 
|---|
| 1769 | /// * The [`RawTableInner`] has already been allocated and has properly initialized | 
|---|
| 1770 | ///   control bytes otherwise calling this function results in [`undefined behavior`]. | 
|---|
| 1771 | /// | 
|---|
| 1772 | /// * The caller of this function must ensure that the "data" parts of the table | 
|---|
| 1773 | ///   will have an entry in the returned index (matching the given hash) right | 
|---|
| 1774 | ///   after calling this function. | 
|---|
| 1775 | /// | 
|---|
| 1776 | /// Attempt to write data at the `index` returned by this function when the table is | 
|---|
| 1777 | /// less than the group width and if there was not at least one empty or deleted bucket in | 
|---|
| 1778 | /// the table will cause immediate [`undefined behavior`]. This is because in this case the | 
|---|
| 1779 | /// function will return `self.bucket_mask + 1` as an index due to the trailing [`Tag::EMPTY`] | 
|---|
| 1780 | /// control bytes outside the table range. | 
|---|
| 1781 | /// | 
|---|
| 1782 | /// The caller must independently increase the `items` field of the table, and also, | 
|---|
| 1783 | /// if the old control byte was [`Tag::EMPTY`], then decrease the table's `growth_left` | 
|---|
| 1784 | /// field, and do not change it if the old control byte was [`Tag::DELETED`]. | 
|---|
| 1785 | /// | 
|---|
| 1786 | /// See also [`Bucket::as_ptr`] method, for more information about of properly removing | 
|---|
| 1787 | /// or saving `element` from / into the [`RawTable`] / [`RawTableInner`]. | 
|---|
| 1788 | /// | 
|---|
| 1789 | /// [`Bucket::as_ptr`]: Bucket::as_ptr | 
|---|
| 1790 | /// [`undefined behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 1791 | /// [`RawTableInner::ctrl`]: RawTableInner::ctrl | 
|---|
| 1792 | /// [`RawTableInner::set_ctrl_hash`]: RawTableInner::set_ctrl_hash | 
|---|
| 1793 | /// [`RawTableInner::find_insert_slot`]: RawTableInner::find_insert_slot | 
|---|
| 1794 | #[ inline] | 
|---|
| 1795 | unsafe fn prepare_insert_slot(&mut self, hash: u64) -> (usize, Tag) { | 
|---|
| 1796 | // SAFETY: Caller of this function ensures that the control bytes are properly initialized. | 
|---|
| 1797 | let index: usize = self.find_insert_slot(hash).index; | 
|---|
| 1798 | // SAFETY: | 
|---|
| 1799 | // 1. The `find_insert_slot` function either returns an `index` less than or | 
|---|
| 1800 | //    equal to `self.buckets() = self.bucket_mask + 1` of the table, or never | 
|---|
| 1801 | //    returns if it cannot find an empty or deleted slot. | 
|---|
| 1802 | // 2. The caller of this function guarantees that the table has already been | 
|---|
| 1803 | //    allocated | 
|---|
| 1804 | let old_ctrl = *self.ctrl(index); | 
|---|
| 1805 | self.set_ctrl_hash(index, hash); | 
|---|
| 1806 | (index, old_ctrl) | 
|---|
| 1807 | } | 
|---|
| 1808 |  | 
|---|
| 1809 | /// Searches for an empty or deleted bucket which is suitable for inserting | 
|---|
| 1810 | /// a new element, returning the `index` for the new [`Bucket`]. | 
|---|
| 1811 | /// | 
|---|
| 1812 | /// This function does not make any changes to the `data` part of the table, or any | 
|---|
| 1813 | /// changes to the `items` or `growth_left` field of the table. | 
|---|
| 1814 | /// | 
|---|
| 1815 | /// The table must have at least 1 empty or deleted `bucket`, otherwise this function | 
|---|
| 1816 | /// will never return (will go into an infinite loop) for tables larger than the group | 
|---|
| 1817 | /// width, or return an index outside of the table indices range if the table is less | 
|---|
| 1818 | /// than the group width. | 
|---|
| 1819 | /// | 
|---|
| 1820 | /// If there is at least 1 empty or deleted `bucket` in the table, the function is | 
|---|
| 1821 | /// guaranteed to return [`InsertSlot`] with an index in the range `0..self.buckets()`, | 
|---|
| 1822 | /// but in any case, if this function returns [`InsertSlot`], it will contain an index | 
|---|
| 1823 | /// in the range `0..=self.buckets()`. | 
|---|
| 1824 | /// | 
|---|
| 1825 | /// # Safety | 
|---|
| 1826 | /// | 
|---|
| 1827 | /// The [`RawTableInner`] must have properly initialized control bytes otherwise calling | 
|---|
| 1828 | /// this function results in [`undefined behavior`]. | 
|---|
| 1829 | /// | 
|---|
| 1830 | /// Attempt to write data at the [`InsertSlot`] returned by this function when the table is | 
|---|
| 1831 | /// less than the group width and if there was not at least one empty or deleted bucket in | 
|---|
| 1832 | /// the table will cause immediate [`undefined behavior`]. This is because in this case the | 
|---|
| 1833 | /// function will return `self.bucket_mask + 1` as an index due to the trailing [`Tag::EMPTY`] | 
|---|
| 1834 | /// control bytes outside the table range. | 
|---|
| 1835 | /// | 
|---|
| 1836 | /// [`undefined behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 1837 | #[ inline] | 
|---|
| 1838 | unsafe fn find_insert_slot(&self, hash: u64) -> InsertSlot { | 
|---|
| 1839 | let mut probe_seq = self.probe_seq(hash); | 
|---|
| 1840 | loop { | 
|---|
| 1841 | // SAFETY: | 
|---|
| 1842 | // * Caller of this function ensures that the control bytes are properly initialized. | 
|---|
| 1843 | // | 
|---|
| 1844 | // * `ProbeSeq.pos` cannot be greater than `self.bucket_mask = self.buckets() - 1` | 
|---|
| 1845 | //   of the table due to masking with `self.bucket_mask` and also because the number | 
|---|
| 1846 | //   of buckets is a power of two (see `self.probe_seq` function). | 
|---|
| 1847 | // | 
|---|
| 1848 | // * Even if `ProbeSeq.pos` returns `position == self.bucket_mask`, it is safe to | 
|---|
| 1849 | //   call `Group::load` due to the extended control bytes range, which is | 
|---|
| 1850 | //  `self.bucket_mask + 1 + Group::WIDTH` (in fact, this means that the last control | 
|---|
| 1851 | //   byte will never be read for the allocated table); | 
|---|
| 1852 | // | 
|---|
| 1853 | // * Also, even if `RawTableInner` is not already allocated, `ProbeSeq.pos` will | 
|---|
| 1854 | //   always return "0" (zero), so Group::load will read unaligned `Group::static_empty()` | 
|---|
| 1855 | //   bytes, which is safe (see RawTableInner::new). | 
|---|
| 1856 | let group = unsafe { Group::load(self.ctrl(probe_seq.pos)) }; | 
|---|
| 1857 |  | 
|---|
| 1858 | let index = self.find_insert_slot_in_group(&group, &probe_seq); | 
|---|
| 1859 | if likely(index.is_some()) { | 
|---|
| 1860 | // SAFETY: | 
|---|
| 1861 | // * Caller of this function ensures that the control bytes are properly initialized. | 
|---|
| 1862 | // | 
|---|
| 1863 | // * We use this function with the slot / index found by `self.find_insert_slot_in_group` | 
|---|
| 1864 | unsafe { | 
|---|
| 1865 | return self.fix_insert_slot(index.unwrap_unchecked()); | 
|---|
| 1866 | } | 
|---|
| 1867 | } | 
|---|
| 1868 | probe_seq.move_next(self.bucket_mask); | 
|---|
| 1869 | } | 
|---|
| 1870 | } | 
|---|
| 1871 |  | 
|---|
| 1872 | /// Searches for an element in a table, returning the `index` of the found element. | 
|---|
| 1873 | /// This uses dynamic dispatch to reduce the amount of code generated, but it is | 
|---|
| 1874 | /// eliminated by LLVM optimizations. | 
|---|
| 1875 | /// | 
|---|
| 1876 | /// This function does not make any changes to the `data` part of the table, or any | 
|---|
| 1877 | /// changes to the `items` or `growth_left` field of the table. | 
|---|
| 1878 | /// | 
|---|
| 1879 | /// The table must have at least 1 empty `bucket`, otherwise, if the | 
|---|
| 1880 | /// `eq: &mut dyn FnMut(usize) -> bool` function does not return `true`, | 
|---|
| 1881 | /// this function will also never return (will go into an infinite loop). | 
|---|
| 1882 | /// | 
|---|
| 1883 | /// This function is guaranteed to provide the `eq: &mut dyn FnMut(usize) -> bool` | 
|---|
| 1884 | /// function with only `FULL` buckets' indices and return the `index` of the found | 
|---|
| 1885 | /// element as `Some(index)`, so the index will always be in the range | 
|---|
| 1886 | /// `0..self.buckets()`. | 
|---|
| 1887 | /// | 
|---|
| 1888 | /// # Safety | 
|---|
| 1889 | /// | 
|---|
| 1890 | /// The [`RawTableInner`] must have properly initialized control bytes otherwise calling | 
|---|
| 1891 | /// this function results in [`undefined behavior`]. | 
|---|
| 1892 | /// | 
|---|
| 1893 | /// [`undefined behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 1894 | #[ inline(always)] | 
|---|
| 1895 | unsafe fn find_inner(&self, hash: u64, eq: &mut dyn FnMut(usize) -> bool) -> Option<usize> { | 
|---|
| 1896 | let tag_hash = Tag::full(hash); | 
|---|
| 1897 | let mut probe_seq = self.probe_seq(hash); | 
|---|
| 1898 |  | 
|---|
| 1899 | loop { | 
|---|
| 1900 | // SAFETY: | 
|---|
| 1901 | // * Caller of this function ensures that the control bytes are properly initialized. | 
|---|
| 1902 | // | 
|---|
| 1903 | // * `ProbeSeq.pos` cannot be greater than `self.bucket_mask = self.buckets() - 1` | 
|---|
| 1904 | //   of the table due to masking with `self.bucket_mask`. | 
|---|
| 1905 | // | 
|---|
| 1906 | // * Even if `ProbeSeq.pos` returns `position == self.bucket_mask`, it is safe to | 
|---|
| 1907 | //   call `Group::load` due to the extended control bytes range, which is | 
|---|
| 1908 | //  `self.bucket_mask + 1 + Group::WIDTH` (in fact, this means that the last control | 
|---|
| 1909 | //   byte will never be read for the allocated table); | 
|---|
| 1910 | // | 
|---|
| 1911 | // * Also, even if `RawTableInner` is not already allocated, `ProbeSeq.pos` will | 
|---|
| 1912 | //   always return "0" (zero), so Group::load will read unaligned `Group::static_empty()` | 
|---|
| 1913 | //   bytes, which is safe (see RawTableInner::new_in). | 
|---|
| 1914 | let group = unsafe { Group::load(self.ctrl(probe_seq.pos)) }; | 
|---|
| 1915 |  | 
|---|
| 1916 | for bit in group.match_tag(tag_hash) { | 
|---|
| 1917 | // This is the same as `(probe_seq.pos + bit) % self.buckets()` because the number | 
|---|
| 1918 | // of buckets is a power of two, and `self.bucket_mask = self.buckets() - 1`. | 
|---|
| 1919 | let index = (probe_seq.pos + bit) & self.bucket_mask; | 
|---|
| 1920 |  | 
|---|
| 1921 | if likely(eq(index)) { | 
|---|
| 1922 | return Some(index); | 
|---|
| 1923 | } | 
|---|
| 1924 | } | 
|---|
| 1925 |  | 
|---|
| 1926 | if likely(group.match_empty().any_bit_set()) { | 
|---|
| 1927 | return None; | 
|---|
| 1928 | } | 
|---|
| 1929 |  | 
|---|
| 1930 | probe_seq.move_next(self.bucket_mask); | 
|---|
| 1931 | } | 
|---|
| 1932 | } | 
|---|
| 1933 |  | 
|---|
| 1934 | /// Prepares for rehashing data in place (that is, without allocating new memory). | 
|---|
| 1935 | /// Converts all full index `control bytes` to `Tag::DELETED` and all `Tag::DELETED` control | 
|---|
| 1936 | /// bytes to `Tag::EMPTY`, i.e. performs the following conversion: | 
|---|
| 1937 | /// | 
|---|
| 1938 | /// - `Tag::EMPTY` control bytes   -> `Tag::EMPTY`; | 
|---|
| 1939 | /// - `Tag::DELETED` control bytes -> `Tag::EMPTY`; | 
|---|
| 1940 | /// - `FULL` control bytes    -> `Tag::DELETED`. | 
|---|
| 1941 | /// | 
|---|
| 1942 | /// This function does not make any changes to the `data` parts of the table, | 
|---|
| 1943 | /// or any changes to the `items` or `growth_left` field of the table. | 
|---|
| 1944 | /// | 
|---|
| 1945 | /// # Safety | 
|---|
| 1946 | /// | 
|---|
| 1947 | /// You must observe the following safety rules when calling this function: | 
|---|
| 1948 | /// | 
|---|
| 1949 | /// * The [`RawTableInner`] has already been allocated; | 
|---|
| 1950 | /// | 
|---|
| 1951 | /// * The caller of this function must convert the `Tag::DELETED` bytes back to `FULL` | 
|---|
| 1952 | ///   bytes when re-inserting them into their ideal position (which was impossible | 
|---|
| 1953 | ///   to do during the first insert due to tombstones). If the caller does not do | 
|---|
| 1954 | ///   this, then calling this function may result in a memory leak. | 
|---|
| 1955 | /// | 
|---|
| 1956 | /// * The [`RawTableInner`] must have properly initialized control bytes otherwise | 
|---|
| 1957 | ///   calling this function results in [`undefined behavior`]. | 
|---|
| 1958 | /// | 
|---|
| 1959 | /// Calling this function on a table that has not been allocated results in | 
|---|
| 1960 | /// [`undefined behavior`]. | 
|---|
| 1961 | /// | 
|---|
| 1962 | /// See also [`Bucket::as_ptr`] method, for more information about of properly removing | 
|---|
| 1963 | /// or saving `data element` from / into the [`RawTable`] / [`RawTableInner`]. | 
|---|
| 1964 | /// | 
|---|
| 1965 | /// [`Bucket::as_ptr`]: Bucket::as_ptr | 
|---|
| 1966 | /// [`undefined behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 1967 | #[ allow(clippy::mut_mut)] | 
|---|
| 1968 | #[ inline] | 
|---|
| 1969 | unsafe fn prepare_rehash_in_place(&mut self) { | 
|---|
| 1970 | // Bulk convert all full control bytes to DELETED, and all DELETED control bytes to EMPTY. | 
|---|
| 1971 | // This effectively frees up all buckets containing a DELETED entry. | 
|---|
| 1972 | // | 
|---|
| 1973 | // SAFETY: | 
|---|
| 1974 | // 1. `i` is guaranteed to be within bounds since we are iterating from zero to `buckets - 1`; | 
|---|
| 1975 | // 2. Even if `i` will be `i == self.bucket_mask`, it is safe to call `Group::load_aligned` | 
|---|
| 1976 | //    due to the extended control bytes range, which is `self.bucket_mask + 1 + Group::WIDTH`; | 
|---|
| 1977 | // 3. The caller of this function guarantees that [`RawTableInner`] has already been allocated; | 
|---|
| 1978 | // 4. We can use `Group::load_aligned` and `Group::store_aligned` here since we start from 0 | 
|---|
| 1979 | //    and go to the end with a step equal to `Group::WIDTH` (see TableLayout::calculate_layout_for). | 
|---|
| 1980 | for i in (0..self.buckets()).step_by(Group::WIDTH) { | 
|---|
| 1981 | let group = Group::load_aligned(self.ctrl(i)); | 
|---|
| 1982 | let group = group.convert_special_to_empty_and_full_to_deleted(); | 
|---|
| 1983 | group.store_aligned(self.ctrl(i)); | 
|---|
| 1984 | } | 
|---|
| 1985 |  | 
|---|
| 1986 | // Fix up the trailing control bytes. See the comments in set_ctrl | 
|---|
| 1987 | // for the handling of tables smaller than the group width. | 
|---|
| 1988 | // | 
|---|
| 1989 | // SAFETY: The caller of this function guarantees that [`RawTableInner`] | 
|---|
| 1990 | // has already been allocated | 
|---|
| 1991 | if unlikely(self.buckets() < Group::WIDTH) { | 
|---|
| 1992 | // SAFETY: We have `self.bucket_mask + 1 + Group::WIDTH` number of control bytes, | 
|---|
| 1993 | // so copying `self.buckets() == self.bucket_mask + 1` bytes with offset equal to | 
|---|
| 1994 | // `Group::WIDTH` is safe | 
|---|
| 1995 | self.ctrl(0) | 
|---|
| 1996 | .copy_to(self.ctrl(Group::WIDTH), self.buckets()); | 
|---|
| 1997 | } else { | 
|---|
| 1998 | // SAFETY: We have `self.bucket_mask + 1 + Group::WIDTH` number of | 
|---|
| 1999 | // control bytes,so copying `Group::WIDTH` bytes with offset equal | 
|---|
| 2000 | // to `self.buckets() == self.bucket_mask + 1` is safe | 
|---|
| 2001 | self.ctrl(0) | 
|---|
| 2002 | .copy_to(self.ctrl(self.buckets()), Group::WIDTH); | 
|---|
| 2003 | } | 
|---|
| 2004 | } | 
|---|
| 2005 |  | 
|---|
| 2006 | /// Returns an iterator over every element in the table. | 
|---|
| 2007 | /// | 
|---|
| 2008 | /// # Safety | 
|---|
| 2009 | /// | 
|---|
| 2010 | /// If any of the following conditions are violated, the result | 
|---|
| 2011 | /// is [`undefined behavior`]: | 
|---|
| 2012 | /// | 
|---|
| 2013 | /// * The caller has to ensure that the `RawTableInner` outlives the | 
|---|
| 2014 | ///   `RawIter`. Because we cannot make the `next` method unsafe on | 
|---|
| 2015 | ///   the `RawIter` struct, we have to make the `iter` method unsafe. | 
|---|
| 2016 | /// | 
|---|
| 2017 | /// * The [`RawTableInner`] must have properly initialized control bytes. | 
|---|
| 2018 | /// | 
|---|
| 2019 | /// The type `T` must be the actual type of the elements stored in the table, | 
|---|
| 2020 | /// otherwise using the returned [`RawIter`] results in [`undefined behavior`]. | 
|---|
| 2021 | /// | 
|---|
| 2022 | /// [`undefined behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 2023 | #[ inline] | 
|---|
| 2024 | unsafe fn iter<T>(&self) -> RawIter<T> { | 
|---|
| 2025 | // SAFETY: | 
|---|
| 2026 | // 1. Since the caller of this function ensures that the control bytes | 
|---|
| 2027 | //    are properly initialized and `self.data_end()` points to the start | 
|---|
| 2028 | //    of the array of control bytes, therefore: `ctrl` is valid for reads, | 
|---|
| 2029 | //    properly aligned to `Group::WIDTH` and points to the properly initialized | 
|---|
| 2030 | //    control bytes. | 
|---|
| 2031 | // 2. `data` bucket index in the table is equal to the `ctrl` index (i.e. | 
|---|
| 2032 | //    equal to zero). | 
|---|
| 2033 | // 3. We pass the exact value of buckets of the table to the function. | 
|---|
| 2034 | // | 
|---|
| 2035 | //                         `ctrl` points here (to the start | 
|---|
| 2036 | //                         of the first control byte `CT0`) | 
|---|
| 2037 | //                          ∨ | 
|---|
| 2038 | // [Pad], T_n, ..., T1, T0, |CT0, CT1, ..., CT_n|, CTa_0, CTa_1, ..., CTa_m | 
|---|
| 2039 | //                           \________  ________/ | 
|---|
| 2040 | //                                    \/ | 
|---|
| 2041 | //       `n = buckets - 1`, i.e. `RawTableInner::buckets() - 1` | 
|---|
| 2042 | // | 
|---|
| 2043 | // where: T0...T_n  - our stored data; | 
|---|
| 2044 | //        CT0...CT_n - control bytes or metadata for `data`. | 
|---|
| 2045 | //        CTa_0...CTa_m - additional control bytes, where `m = Group::WIDTH - 1` (so that the search | 
|---|
| 2046 | //                        with loading `Group` bytes from the heap works properly, even if the result | 
|---|
| 2047 | //                        of `h1(hash) & self.bucket_mask` is equal to `self.bucket_mask`). See also | 
|---|
| 2048 | //                        `RawTableInner::set_ctrl` function. | 
|---|
| 2049 | // | 
|---|
| 2050 | // P.S. `h1(hash) & self.bucket_mask` is the same as `hash as usize % self.buckets()` because the number | 
|---|
| 2051 | // of buckets is a power of two, and `self.bucket_mask = self.buckets() - 1`. | 
|---|
| 2052 | let data = Bucket::from_base_index(self.data_end(), 0); | 
|---|
| 2053 | RawIter { | 
|---|
| 2054 | // SAFETY: See explanation above | 
|---|
| 2055 | iter: RawIterRange::new(self.ctrl.as_ptr(), data, self.buckets()), | 
|---|
| 2056 | items: self.items, | 
|---|
| 2057 | } | 
|---|
| 2058 | } | 
|---|
| 2059 |  | 
|---|
| 2060 | /// Executes the destructors (if any) of the values stored in the table. | 
|---|
| 2061 | /// | 
|---|
| 2062 | /// # Note | 
|---|
| 2063 | /// | 
|---|
| 2064 | /// This function does not erase the control bytes of the table and does | 
|---|
| 2065 | /// not make any changes to the `items` or `growth_left` fields of the | 
|---|
| 2066 | /// table. If necessary, the caller of this function must manually set | 
|---|
| 2067 | /// up these table fields, for example using the [`clear_no_drop`] function. | 
|---|
| 2068 | /// | 
|---|
| 2069 | /// Be careful during calling this function, because drop function of | 
|---|
| 2070 | /// the elements can panic, and this can leave table in an inconsistent | 
|---|
| 2071 | /// state. | 
|---|
| 2072 | /// | 
|---|
| 2073 | /// # Safety | 
|---|
| 2074 | /// | 
|---|
| 2075 | /// The type `T` must be the actual type of the elements stored in the table, | 
|---|
| 2076 | /// otherwise calling this function may result in [`undefined behavior`]. | 
|---|
| 2077 | /// | 
|---|
| 2078 | /// If `T` is a type that should be dropped and **the table is not empty**, | 
|---|
| 2079 | /// calling this function more than once results in [`undefined behavior`]. | 
|---|
| 2080 | /// | 
|---|
| 2081 | /// If `T` is not [`Copy`], attempting to use values stored in the table after | 
|---|
| 2082 | /// calling this function may result in [`undefined behavior`]. | 
|---|
| 2083 | /// | 
|---|
| 2084 | /// It is safe to call this function on a table that has not been allocated, | 
|---|
| 2085 | /// on a table with uninitialized control bytes, and on a table with no actual | 
|---|
| 2086 | /// data but with `Full` control bytes if `self.items == 0`. | 
|---|
| 2087 | /// | 
|---|
| 2088 | /// See also [`Bucket::drop`] / [`Bucket::as_ptr`] methods, for more information | 
|---|
| 2089 | /// about of properly removing or saving `element` from / into the [`RawTable`] / | 
|---|
| 2090 | /// [`RawTableInner`]. | 
|---|
| 2091 | /// | 
|---|
| 2092 | /// [`Bucket::drop`]: Bucket::drop | 
|---|
| 2093 | /// [`Bucket::as_ptr`]: Bucket::as_ptr | 
|---|
| 2094 | /// [`clear_no_drop`]: RawTableInner::clear_no_drop | 
|---|
| 2095 | /// [`undefined behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 2096 | unsafe fn drop_elements<T>(&mut self) { | 
|---|
| 2097 | // Check that `self.items != 0`. Protects against the possibility | 
|---|
| 2098 | // of creating an iterator on an table with uninitialized control bytes. | 
|---|
| 2099 | if T::NEEDS_DROP && self.items != 0 { | 
|---|
| 2100 | // SAFETY: We know for sure that RawTableInner will outlive the | 
|---|
| 2101 | // returned `RawIter` iterator, and the caller of this function | 
|---|
| 2102 | // must uphold the safety contract for `drop_elements` method. | 
|---|
| 2103 | for item in self.iter::<T>() { | 
|---|
| 2104 | // SAFETY: The caller must uphold the safety contract for | 
|---|
| 2105 | // `drop_elements` method. | 
|---|
| 2106 | item.drop(); | 
|---|
| 2107 | } | 
|---|
| 2108 | } | 
|---|
| 2109 | } | 
|---|
| 2110 |  | 
|---|
| 2111 | /// Executes the destructors (if any) of the values stored in the table and than | 
|---|
| 2112 | /// deallocates the table. | 
|---|
| 2113 | /// | 
|---|
| 2114 | /// # Note | 
|---|
| 2115 | /// | 
|---|
| 2116 | /// Calling this function automatically makes invalid (dangling) all instances of | 
|---|
| 2117 | /// buckets ([`Bucket`]) and makes invalid (dangling) the `ctrl` field of the table. | 
|---|
| 2118 | /// | 
|---|
| 2119 | /// This function does not make any changes to the `bucket_mask`, `items` or `growth_left` | 
|---|
| 2120 | /// fields of the table. If necessary, the caller of this function must manually set | 
|---|
| 2121 | /// up these table fields. | 
|---|
| 2122 | /// | 
|---|
| 2123 | /// # Safety | 
|---|
| 2124 | /// | 
|---|
| 2125 | /// If any of the following conditions are violated, the result is [`undefined behavior`]: | 
|---|
| 2126 | /// | 
|---|
| 2127 | /// * Calling this function more than once; | 
|---|
| 2128 | /// | 
|---|
| 2129 | /// * The type `T` must be the actual type of the elements stored in the table. | 
|---|
| 2130 | /// | 
|---|
| 2131 | /// * The `alloc` must be the same [`Allocator`] as the `Allocator` that was used | 
|---|
| 2132 | ///   to allocate this table. | 
|---|
| 2133 | /// | 
|---|
| 2134 | /// * The `table_layout` must be the same [`TableLayout`] as the `TableLayout` that | 
|---|
| 2135 | ///   was used to allocate this table. | 
|---|
| 2136 | /// | 
|---|
| 2137 | /// The caller of this function should pay attention to the possibility of the | 
|---|
| 2138 | /// elements' drop function panicking, because this: | 
|---|
| 2139 | /// | 
|---|
| 2140 | ///    * May leave the table in an inconsistent state; | 
|---|
| 2141 | /// | 
|---|
| 2142 | ///    * Memory is never deallocated, so a memory leak may occur. | 
|---|
| 2143 | /// | 
|---|
| 2144 | /// Attempt to use the `ctrl` field of the table (dereference) after calling this | 
|---|
| 2145 | /// function results in [`undefined behavior`]. | 
|---|
| 2146 | /// | 
|---|
| 2147 | /// It is safe to call this function on a table that has not been allocated, | 
|---|
| 2148 | /// on a table with uninitialized control bytes, and on a table with no actual | 
|---|
| 2149 | /// data but with `Full` control bytes if `self.items == 0`. | 
|---|
| 2150 | /// | 
|---|
| 2151 | /// See also [`RawTableInner::drop_elements`] or [`RawTableInner::free_buckets`] | 
|---|
| 2152 | /// for more  information. | 
|---|
| 2153 | /// | 
|---|
| 2154 | /// [`RawTableInner::drop_elements`]: RawTableInner::drop_elements | 
|---|
| 2155 | /// [`RawTableInner::free_buckets`]: RawTableInner::free_buckets | 
|---|
| 2156 | /// [`undefined behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 2157 | unsafe fn drop_inner_table<T, A: Allocator>(&mut self, alloc: &A, table_layout: TableLayout) { | 
|---|
| 2158 | if !self.is_empty_singleton() { | 
|---|
| 2159 | unsafe { | 
|---|
| 2160 | // SAFETY: The caller must uphold the safety contract for `drop_inner_table` method. | 
|---|
| 2161 | self.drop_elements::<T>(); | 
|---|
| 2162 | // SAFETY: | 
|---|
| 2163 | // 1. We have checked that our table is allocated. | 
|---|
| 2164 | // 2. The caller must uphold the safety contract for `drop_inner_table` method. | 
|---|
| 2165 | self.free_buckets(alloc, table_layout); | 
|---|
| 2166 | } | 
|---|
| 2167 | } | 
|---|
| 2168 | } | 
|---|
| 2169 |  | 
|---|
| 2170 | /// Returns a pointer to an element in the table (convenience for | 
|---|
| 2171 | /// `Bucket::from_base_index(self.data_end::<T>(), index)`). | 
|---|
| 2172 | /// | 
|---|
| 2173 | /// The caller must ensure that the `RawTableInner` outlives the returned [`Bucket<T>`], | 
|---|
| 2174 | /// otherwise using it may result in [`undefined behavior`]. | 
|---|
| 2175 | /// | 
|---|
| 2176 | /// # Safety | 
|---|
| 2177 | /// | 
|---|
| 2178 | /// If `mem::size_of::<T>() != 0`, then the safety rules are directly derived from the | 
|---|
| 2179 | /// safety rules of the [`Bucket::from_base_index`] function. Therefore, when calling | 
|---|
| 2180 | /// this function, the following safety rules must be observed: | 
|---|
| 2181 | /// | 
|---|
| 2182 | /// * The table must already be allocated; | 
|---|
| 2183 | /// | 
|---|
| 2184 | /// * The `index` must not be greater than the number returned by the [`RawTableInner::buckets`] | 
|---|
| 2185 | ///   function, i.e. `(index + 1) <= self.buckets()`. | 
|---|
| 2186 | /// | 
|---|
| 2187 | /// * The type `T` must be the actual type of the elements stored in the table, otherwise | 
|---|
| 2188 | ///   using the returned [`Bucket`] may result in [`undefined behavior`]. | 
|---|
| 2189 | /// | 
|---|
| 2190 | /// It is safe to call this function with index of zero (`index == 0`) on a table that has | 
|---|
| 2191 | /// not been allocated, but using the returned [`Bucket`] results in [`undefined behavior`]. | 
|---|
| 2192 | /// | 
|---|
| 2193 | /// If `mem::size_of::<T>() == 0`, then the only requirement is that the `index` must | 
|---|
| 2194 | /// not be greater than the number returned by the [`RawTable::buckets`] function, i.e. | 
|---|
| 2195 | /// `(index + 1) <= self.buckets()`. | 
|---|
| 2196 | /// | 
|---|
| 2197 | /// ```none | 
|---|
| 2198 | /// If mem::size_of::<T>() != 0 then return a pointer to the `element` in the `data part` of the table | 
|---|
| 2199 | /// (we start counting from "0", so that in the expression T[n], the "n" index actually one less than | 
|---|
| 2200 | /// the "buckets" number of our `RawTableInner`, i.e. "n = RawTableInner::buckets() - 1"): | 
|---|
| 2201 | /// | 
|---|
| 2202 | ///           `table.bucket(3).as_ptr()` returns a pointer that points here in the `data` | 
|---|
| 2203 | ///           part of the `RawTableInner`, i.e. to the start of T3 (see [`Bucket::as_ptr`]) | 
|---|
| 2204 | ///                  | | 
|---|
| 2205 | ///                  |               `base = table.data_end::<T>()` points here | 
|---|
| 2206 | ///                  |               (to the start of CT0 or to the end of T0) | 
|---|
| 2207 | ///                  v                 v | 
|---|
| 2208 | /// [Pad], T_n, ..., |T3|, T2, T1, T0, |CT0, CT1, CT2, CT3, ..., CT_n, CTa_0, CTa_1, ..., CTa_m | 
|---|
| 2209 | ///                     ^                                              \__________  __________/ | 
|---|
| 2210 | ///        `table.bucket(3)` returns a pointer that points                        \/ | 
|---|
| 2211 | ///         here in the `data` part of the `RawTableInner`             additional control bytes | 
|---|
| 2212 | ///         (to the end of T3)                                          `m = Group::WIDTH - 1` | 
|---|
| 2213 | /// | 
|---|
| 2214 | /// where: T0...T_n  - our stored data; | 
|---|
| 2215 | ///        CT0...CT_n - control bytes or metadata for `data`; | 
|---|
| 2216 | ///        CTa_0...CTa_m - additional control bytes (so that the search with loading `Group` bytes from | 
|---|
| 2217 | ///                        the heap works properly, even if the result of `h1(hash) & self.bucket_mask` | 
|---|
| 2218 | ///                        is equal to `self.bucket_mask`). See also `RawTableInner::set_ctrl` function. | 
|---|
| 2219 | /// | 
|---|
| 2220 | /// P.S. `h1(hash) & self.bucket_mask` is the same as `hash as usize % self.buckets()` because the number | 
|---|
| 2221 | /// of buckets is a power of two, and `self.bucket_mask = self.buckets() - 1`. | 
|---|
| 2222 | /// ``` | 
|---|
| 2223 | /// | 
|---|
| 2224 | /// [`Bucket::from_base_index`]: Bucket::from_base_index | 
|---|
| 2225 | /// [`RawTableInner::buckets`]: RawTableInner::buckets | 
|---|
| 2226 | /// [`undefined behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 2227 | #[ inline] | 
|---|
| 2228 | unsafe fn bucket<T>(&self, index: usize) -> Bucket<T> { | 
|---|
| 2229 | debug_assert_ne!(self.bucket_mask, 0); | 
|---|
| 2230 | debug_assert!(index < self.buckets()); | 
|---|
| 2231 | Bucket::from_base_index(self.data_end(), index) | 
|---|
| 2232 | } | 
|---|
| 2233 |  | 
|---|
| 2234 | /// Returns a raw `*mut u8` pointer to the start of the `data` element in the table | 
|---|
| 2235 | /// (convenience for `self.data_end::<u8>().as_ptr().sub((index + 1) * size_of)`). | 
|---|
| 2236 | /// | 
|---|
| 2237 | /// The caller must ensure that the `RawTableInner` outlives the returned `*mut u8`, | 
|---|
| 2238 | /// otherwise using it may result in [`undefined behavior`]. | 
|---|
| 2239 | /// | 
|---|
| 2240 | /// # Safety | 
|---|
| 2241 | /// | 
|---|
| 2242 | /// If any of the following conditions are violated, the result is [`undefined behavior`]: | 
|---|
| 2243 | /// | 
|---|
| 2244 | /// * The table must already be allocated; | 
|---|
| 2245 | /// | 
|---|
| 2246 | /// * The `index` must not be greater than the number returned by the [`RawTableInner::buckets`] | 
|---|
| 2247 | ///   function, i.e. `(index + 1) <= self.buckets()`; | 
|---|
| 2248 | /// | 
|---|
| 2249 | /// * The `size_of` must be equal to the size of the elements stored in the table; | 
|---|
| 2250 | /// | 
|---|
| 2251 | /// ```none | 
|---|
| 2252 | /// If mem::size_of::<T>() != 0 then return a pointer to the `element` in the `data part` of the table | 
|---|
| 2253 | /// (we start counting from "0", so that in the expression T[n], the "n" index actually one less than | 
|---|
| 2254 | /// the "buckets" number of our `RawTableInner`, i.e. "n = RawTableInner::buckets() - 1"): | 
|---|
| 2255 | /// | 
|---|
| 2256 | ///           `table.bucket_ptr(3, mem::size_of::<T>())` returns a pointer that points here in the | 
|---|
| 2257 | ///           `data` part of the `RawTableInner`, i.e. to the start of T3 | 
|---|
| 2258 | ///                  | | 
|---|
| 2259 | ///                  |               `base = table.data_end::<u8>()` points here | 
|---|
| 2260 | ///                  |               (to the start of CT0 or to the end of T0) | 
|---|
| 2261 | ///                  v                 v | 
|---|
| 2262 | /// [Pad], T_n, ..., |T3|, T2, T1, T0, |CT0, CT1, CT2, CT3, ..., CT_n, CTa_0, CTa_1, ..., CTa_m | 
|---|
| 2263 | ///                                                                    \__________  __________/ | 
|---|
| 2264 | ///                                                                               \/ | 
|---|
| 2265 | ///                                                                    additional control bytes | 
|---|
| 2266 | ///                                                                     `m = Group::WIDTH - 1` | 
|---|
| 2267 | /// | 
|---|
| 2268 | /// where: T0...T_n  - our stored data; | 
|---|
| 2269 | ///        CT0...CT_n - control bytes or metadata for `data`; | 
|---|
| 2270 | ///        CTa_0...CTa_m - additional control bytes (so that the search with loading `Group` bytes from | 
|---|
| 2271 | ///                        the heap works properly, even if the result of `h1(hash) & self.bucket_mask` | 
|---|
| 2272 | ///                        is equal to `self.bucket_mask`). See also `RawTableInner::set_ctrl` function. | 
|---|
| 2273 | /// | 
|---|
| 2274 | /// P.S. `h1(hash) & self.bucket_mask` is the same as `hash as usize % self.buckets()` because the number | 
|---|
| 2275 | /// of buckets is a power of two, and `self.bucket_mask = self.buckets() - 1`. | 
|---|
| 2276 | /// ``` | 
|---|
| 2277 | /// | 
|---|
| 2278 | /// [`RawTableInner::buckets`]: RawTableInner::buckets | 
|---|
| 2279 | /// [`undefined behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 2280 | #[ inline] | 
|---|
| 2281 | unsafe fn bucket_ptr(&self, index: usize, size_of: usize) -> *mut u8 { | 
|---|
| 2282 | debug_assert_ne!(self.bucket_mask, 0); | 
|---|
| 2283 | debug_assert!(index < self.buckets()); | 
|---|
| 2284 | let base: *mut u8 = self.data_end().as_ptr(); | 
|---|
| 2285 | base.sub((index + 1) * size_of) | 
|---|
| 2286 | } | 
|---|
| 2287 |  | 
|---|
| 2288 | /// Returns pointer to one past last `data` element in the table as viewed from | 
|---|
| 2289 | /// the start point of the allocation (convenience for `self.ctrl.cast()`). | 
|---|
| 2290 | /// | 
|---|
| 2291 | /// This function actually returns a pointer to the end of the `data element` at | 
|---|
| 2292 | /// index "0" (zero). | 
|---|
| 2293 | /// | 
|---|
| 2294 | /// The caller must ensure that the `RawTableInner` outlives the returned [`NonNull<T>`], | 
|---|
| 2295 | /// otherwise using it may result in [`undefined behavior`]. | 
|---|
| 2296 | /// | 
|---|
| 2297 | /// # Note | 
|---|
| 2298 | /// | 
|---|
| 2299 | /// The type `T` must be the actual type of the elements stored in the table, otherwise | 
|---|
| 2300 | /// using the returned [`NonNull<T>`] may result in [`undefined behavior`]. | 
|---|
| 2301 | /// | 
|---|
| 2302 | /// ```none | 
|---|
| 2303 | ///                        `table.data_end::<T>()` returns pointer that points here | 
|---|
| 2304 | ///                        (to the end of `T0`) | 
|---|
| 2305 | ///                          ∨ | 
|---|
| 2306 | /// [Pad], T_n, ..., T1, T0, |CT0, CT1, ..., CT_n|, CTa_0, CTa_1, ..., CTa_m | 
|---|
| 2307 | ///                           \________  ________/ | 
|---|
| 2308 | ///                                    \/ | 
|---|
| 2309 | ///       `n = buckets - 1`, i.e. `RawTableInner::buckets() - 1` | 
|---|
| 2310 | /// | 
|---|
| 2311 | /// where: T0...T_n  - our stored data; | 
|---|
| 2312 | ///        CT0...CT_n - control bytes or metadata for `data`. | 
|---|
| 2313 | ///        CTa_0...CTa_m - additional control bytes, where `m = Group::WIDTH - 1` (so that the search | 
|---|
| 2314 | ///                        with loading `Group` bytes from the heap works properly, even if the result | 
|---|
| 2315 | ///                        of `h1(hash) & self.bucket_mask` is equal to `self.bucket_mask`). See also | 
|---|
| 2316 | ///                        `RawTableInner::set_ctrl` function. | 
|---|
| 2317 | /// | 
|---|
| 2318 | /// P.S. `h1(hash) & self.bucket_mask` is the same as `hash as usize % self.buckets()` because the number | 
|---|
| 2319 | /// of buckets is a power of two, and `self.bucket_mask = self.buckets() - 1`. | 
|---|
| 2320 | /// ``` | 
|---|
| 2321 | /// | 
|---|
| 2322 | /// [`undefined behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 2323 | #[ inline] | 
|---|
| 2324 | fn data_end<T>(&self) -> NonNull<T> { | 
|---|
| 2325 | self.ctrl.cast() | 
|---|
| 2326 | } | 
|---|
| 2327 |  | 
|---|
| 2328 | /// Returns an iterator-like object for a probe sequence on the table. | 
|---|
| 2329 | /// | 
|---|
| 2330 | /// This iterator never terminates, but is guaranteed to visit each bucket | 
|---|
| 2331 | /// group exactly once. The loop using `probe_seq` must terminate upon | 
|---|
| 2332 | /// reaching a group containing an empty bucket. | 
|---|
| 2333 | #[ inline] | 
|---|
| 2334 | fn probe_seq(&self, hash: u64) -> ProbeSeq { | 
|---|
| 2335 | ProbeSeq { | 
|---|
| 2336 | // This is the same as `hash as usize % self.buckets()` because the number | 
|---|
| 2337 | // of buckets is a power of two, and `self.bucket_mask = self.buckets() - 1`. | 
|---|
| 2338 | pos: h1(hash) & self.bucket_mask, | 
|---|
| 2339 | stride: 0, | 
|---|
| 2340 | } | 
|---|
| 2341 | } | 
|---|
| 2342 |  | 
|---|
| 2343 | #[ inline] | 
|---|
| 2344 | unsafe fn record_item_insert_at(&mut self, index: usize, old_ctrl: Tag, hash: u64) { | 
|---|
| 2345 | self.growth_left -= usize::from(old_ctrl.special_is_empty()); | 
|---|
| 2346 | self.set_ctrl_hash(index, hash); | 
|---|
| 2347 | self.items += 1; | 
|---|
| 2348 | } | 
|---|
| 2349 |  | 
|---|
| 2350 | #[ inline] | 
|---|
| 2351 | fn is_in_same_group(&self, i: usize, new_i: usize, hash: u64) -> bool { | 
|---|
| 2352 | let probe_seq_pos = self.probe_seq(hash).pos; | 
|---|
| 2353 | let probe_index = | 
|---|
| 2354 | |pos: usize| (pos.wrapping_sub(probe_seq_pos) & self.bucket_mask) / Group::WIDTH; | 
|---|
| 2355 | probe_index(i) == probe_index(new_i) | 
|---|
| 2356 | } | 
|---|
| 2357 |  | 
|---|
| 2358 | /// Sets a control byte to the hash, and possibly also the replicated control byte at | 
|---|
| 2359 | /// the end of the array. | 
|---|
| 2360 | /// | 
|---|
| 2361 | /// This function does not make any changes to the `data` parts of the table, | 
|---|
| 2362 | /// or any changes to the `items` or `growth_left` field of the table. | 
|---|
| 2363 | /// | 
|---|
| 2364 | /// # Safety | 
|---|
| 2365 | /// | 
|---|
| 2366 | /// The safety rules are directly derived from the safety rules for [`RawTableInner::set_ctrl`] | 
|---|
| 2367 | /// method. Thus, in order to uphold the safety contracts for the method, you must observe the | 
|---|
| 2368 | /// following rules when calling this function: | 
|---|
| 2369 | /// | 
|---|
| 2370 | /// * The [`RawTableInner`] has already been allocated; | 
|---|
| 2371 | /// | 
|---|
| 2372 | /// * The `index` must not be greater than the `RawTableInner.bucket_mask`, i.e. | 
|---|
| 2373 | ///   `index <= RawTableInner.bucket_mask` or, in other words, `(index + 1)` must | 
|---|
| 2374 | ///   be no greater than the number returned by the function [`RawTableInner::buckets`]. | 
|---|
| 2375 | /// | 
|---|
| 2376 | /// Calling this function on a table that has not been allocated results in [`undefined behavior`]. | 
|---|
| 2377 | /// | 
|---|
| 2378 | /// See also [`Bucket::as_ptr`] method, for more information about of properly removing | 
|---|
| 2379 | /// or saving `data element` from / into the [`RawTable`] / [`RawTableInner`]. | 
|---|
| 2380 | /// | 
|---|
| 2381 | /// [`RawTableInner::set_ctrl`]: RawTableInner::set_ctrl | 
|---|
| 2382 | /// [`RawTableInner::buckets`]: RawTableInner::buckets | 
|---|
| 2383 | /// [`Bucket::as_ptr`]: Bucket::as_ptr | 
|---|
| 2384 | /// [`undefined behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 2385 | #[ inline] | 
|---|
| 2386 | unsafe fn set_ctrl_hash(&mut self, index: usize, hash: u64) { | 
|---|
| 2387 | // SAFETY: The caller must uphold the safety rules for the [`RawTableInner::set_ctrl_hash`] | 
|---|
| 2388 | self.set_ctrl(index, Tag::full(hash)); | 
|---|
| 2389 | } | 
|---|
| 2390 |  | 
|---|
| 2391 | /// Replaces the hash in the control byte at the given index with the provided one, | 
|---|
| 2392 | /// and possibly also replicates the new control byte at the end of the array of control | 
|---|
| 2393 | /// bytes, returning the old control byte. | 
|---|
| 2394 | /// | 
|---|
| 2395 | /// This function does not make any changes to the `data` parts of the table, | 
|---|
| 2396 | /// or any changes to the `items` or `growth_left` field of the table. | 
|---|
| 2397 | /// | 
|---|
| 2398 | /// # Safety | 
|---|
| 2399 | /// | 
|---|
| 2400 | /// The safety rules are directly derived from the safety rules for [`RawTableInner::set_ctrl_hash`] | 
|---|
| 2401 | /// and [`RawTableInner::ctrl`] methods. Thus, in order to uphold the safety contracts for both | 
|---|
| 2402 | /// methods, you must observe the following rules when calling this function: | 
|---|
| 2403 | /// | 
|---|
| 2404 | /// * The [`RawTableInner`] has already been allocated; | 
|---|
| 2405 | /// | 
|---|
| 2406 | /// * The `index` must not be greater than the `RawTableInner.bucket_mask`, i.e. | 
|---|
| 2407 | ///   `index <= RawTableInner.bucket_mask` or, in other words, `(index + 1)` must | 
|---|
| 2408 | ///   be no greater than the number returned by the function [`RawTableInner::buckets`]. | 
|---|
| 2409 | /// | 
|---|
| 2410 | /// Calling this function on a table that has not been allocated results in [`undefined behavior`]. | 
|---|
| 2411 | /// | 
|---|
| 2412 | /// See also [`Bucket::as_ptr`] method, for more information about of properly removing | 
|---|
| 2413 | /// or saving `data element` from / into the [`RawTable`] / [`RawTableInner`]. | 
|---|
| 2414 | /// | 
|---|
| 2415 | /// [`RawTableInner::set_ctrl_hash`]: RawTableInner::set_ctrl_hash | 
|---|
| 2416 | /// [`RawTableInner::buckets`]: RawTableInner::buckets | 
|---|
| 2417 | /// [`Bucket::as_ptr`]: Bucket::as_ptr | 
|---|
| 2418 | /// [`undefined behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 2419 | #[ inline] | 
|---|
| 2420 | unsafe fn replace_ctrl_hash(&mut self, index: usize, hash: u64) -> Tag { | 
|---|
| 2421 | // SAFETY: The caller must uphold the safety rules for the [`RawTableInner::replace_ctrl_hash`] | 
|---|
| 2422 | let prev_ctrl = *self.ctrl(index); | 
|---|
| 2423 | self.set_ctrl_hash(index, hash); | 
|---|
| 2424 | prev_ctrl | 
|---|
| 2425 | } | 
|---|
| 2426 |  | 
|---|
| 2427 | /// Sets a control byte, and possibly also the replicated control byte at | 
|---|
| 2428 | /// the end of the array. | 
|---|
| 2429 | /// | 
|---|
| 2430 | /// This function does not make any changes to the `data` parts of the table, | 
|---|
| 2431 | /// or any changes to the `items` or `growth_left` field of the table. | 
|---|
| 2432 | /// | 
|---|
| 2433 | /// # Safety | 
|---|
| 2434 | /// | 
|---|
| 2435 | /// You must observe the following safety rules when calling this function: | 
|---|
| 2436 | /// | 
|---|
| 2437 | /// * The [`RawTableInner`] has already been allocated; | 
|---|
| 2438 | /// | 
|---|
| 2439 | /// * The `index` must not be greater than the `RawTableInner.bucket_mask`, i.e. | 
|---|
| 2440 | ///   `index <= RawTableInner.bucket_mask` or, in other words, `(index + 1)` must | 
|---|
| 2441 | ///   be no greater than the number returned by the function [`RawTableInner::buckets`]. | 
|---|
| 2442 | /// | 
|---|
| 2443 | /// Calling this function on a table that has not been allocated results in [`undefined behavior`]. | 
|---|
| 2444 | /// | 
|---|
| 2445 | /// See also [`Bucket::as_ptr`] method, for more information about of properly removing | 
|---|
| 2446 | /// or saving `data element` from / into the [`RawTable`] / [`RawTableInner`]. | 
|---|
| 2447 | /// | 
|---|
| 2448 | /// [`RawTableInner::buckets`]: RawTableInner::buckets | 
|---|
| 2449 | /// [`Bucket::as_ptr`]: Bucket::as_ptr | 
|---|
| 2450 | /// [`undefined behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 2451 | #[ inline] | 
|---|
| 2452 | unsafe fn set_ctrl(&mut self, index: usize, ctrl: Tag) { | 
|---|
| 2453 | // Replicate the first Group::WIDTH control bytes at the end of | 
|---|
| 2454 | // the array without using a branch. If the tables smaller than | 
|---|
| 2455 | // the group width (self.buckets() < Group::WIDTH), | 
|---|
| 2456 | // `index2 = Group::WIDTH + index`, otherwise `index2` is: | 
|---|
| 2457 | // | 
|---|
| 2458 | // - If index >= Group::WIDTH then index == index2. | 
|---|
| 2459 | // - Otherwise index2 == self.bucket_mask + 1 + index. | 
|---|
| 2460 | // | 
|---|
| 2461 | // The very last replicated control byte is never actually read because | 
|---|
| 2462 | // we mask the initial index for unaligned loads, but we write it | 
|---|
| 2463 | // anyways because it makes the set_ctrl implementation simpler. | 
|---|
| 2464 | // | 
|---|
| 2465 | // If there are fewer buckets than Group::WIDTH then this code will | 
|---|
| 2466 | // replicate the buckets at the end of the trailing group. For example | 
|---|
| 2467 | // with 2 buckets and a group size of 4, the control bytes will look | 
|---|
| 2468 | // like this: | 
|---|
| 2469 | // | 
|---|
| 2470 | //     Real    |             Replicated | 
|---|
| 2471 | // --------------------------------------------- | 
|---|
| 2472 | // | [A] | [B] | [Tag::EMPTY] | [EMPTY] | [A] | [B] | | 
|---|
| 2473 | // --------------------------------------------- | 
|---|
| 2474 |  | 
|---|
| 2475 | // This is the same as `(index.wrapping_sub(Group::WIDTH)) % self.buckets() + Group::WIDTH` | 
|---|
| 2476 | // because the number of buckets is a power of two, and `self.bucket_mask = self.buckets() - 1`. | 
|---|
| 2477 | let index2 = ((index.wrapping_sub(Group::WIDTH)) & self.bucket_mask) + Group::WIDTH; | 
|---|
| 2478 |  | 
|---|
| 2479 | // SAFETY: The caller must uphold the safety rules for the [`RawTableInner::set_ctrl`] | 
|---|
| 2480 | *self.ctrl(index) = ctrl; | 
|---|
| 2481 | *self.ctrl(index2) = ctrl; | 
|---|
| 2482 | } | 
|---|
| 2483 |  | 
|---|
| 2484 | /// Returns a pointer to a control byte. | 
|---|
| 2485 | /// | 
|---|
| 2486 | /// # Safety | 
|---|
| 2487 | /// | 
|---|
| 2488 | /// For the allocated [`RawTableInner`], the result is [`Undefined Behavior`], | 
|---|
| 2489 | /// if the `index` is greater than the `self.bucket_mask + 1 + Group::WIDTH`. | 
|---|
| 2490 | /// In that case, calling this function with `index == self.bucket_mask + 1 + Group::WIDTH` | 
|---|
| 2491 | /// will return a pointer to the end of the allocated table and it is useless on its own. | 
|---|
| 2492 | /// | 
|---|
| 2493 | /// Calling this function with `index >= self.bucket_mask + 1 + Group::WIDTH` on a | 
|---|
| 2494 | /// table that has not been allocated results in [`Undefined Behavior`]. | 
|---|
| 2495 | /// | 
|---|
| 2496 | /// So to satisfy both requirements you should always follow the rule that | 
|---|
| 2497 | /// `index < self.bucket_mask + 1 + Group::WIDTH` | 
|---|
| 2498 | /// | 
|---|
| 2499 | /// Calling this function on [`RawTableInner`] that are not already allocated is safe | 
|---|
| 2500 | /// for read-only purpose. | 
|---|
| 2501 | /// | 
|---|
| 2502 | /// See also [`Bucket::as_ptr()`] method, for more information about of properly removing | 
|---|
| 2503 | /// or saving `data element` from / into the [`RawTable`] / [`RawTableInner`]. | 
|---|
| 2504 | /// | 
|---|
| 2505 | /// [`Bucket::as_ptr()`]: Bucket::as_ptr() | 
|---|
| 2506 | /// [`Undefined Behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 2507 | #[ inline] | 
|---|
| 2508 | unsafe fn ctrl(&self, index: usize) -> *mut Tag { | 
|---|
| 2509 | debug_assert!(index < self.num_ctrl_bytes()); | 
|---|
| 2510 | // SAFETY: The caller must uphold the safety rules for the [`RawTableInner::ctrl`] | 
|---|
| 2511 | self.ctrl.as_ptr().add(index).cast() | 
|---|
| 2512 | } | 
|---|
| 2513 |  | 
|---|
| 2514 | /// Gets the slice of all control bytes. | 
|---|
| 2515 | fn ctrl_slice(&mut self) -> &mut [Tag] { | 
|---|
| 2516 | // SAFETY: We've intiailized all control bytes, and have the correct number. | 
|---|
| 2517 | unsafe { slice::from_raw_parts_mut(self.ctrl.as_ptr().cast(), self.num_ctrl_bytes()) } | 
|---|
| 2518 | } | 
|---|
| 2519 |  | 
|---|
| 2520 | #[ inline] | 
|---|
| 2521 | fn buckets(&self) -> usize { | 
|---|
| 2522 | self.bucket_mask + 1 | 
|---|
| 2523 | } | 
|---|
| 2524 |  | 
|---|
| 2525 | /// Checks whether the bucket at `index` is full. | 
|---|
| 2526 | /// | 
|---|
| 2527 | /// # Safety | 
|---|
| 2528 | /// | 
|---|
| 2529 | /// The caller must ensure `index` is less than the number of buckets. | 
|---|
| 2530 | #[ inline] | 
|---|
| 2531 | unsafe fn is_bucket_full(&self, index: usize) -> bool { | 
|---|
| 2532 | debug_assert!(index < self.buckets()); | 
|---|
| 2533 | (*self.ctrl(index)).is_full() | 
|---|
| 2534 | } | 
|---|
| 2535 |  | 
|---|
| 2536 | #[ inline] | 
|---|
| 2537 | fn num_ctrl_bytes(&self) -> usize { | 
|---|
| 2538 | self.bucket_mask + 1 + Group::WIDTH | 
|---|
| 2539 | } | 
|---|
| 2540 |  | 
|---|
| 2541 | #[ inline] | 
|---|
| 2542 | fn is_empty_singleton(&self) -> bool { | 
|---|
| 2543 | self.bucket_mask == 0 | 
|---|
| 2544 | } | 
|---|
| 2545 |  | 
|---|
| 2546 | /// Attempts to allocate a new hash table with at least enough capacity | 
|---|
| 2547 | /// for inserting the given number of elements without reallocating, | 
|---|
| 2548 | /// and return it inside `ScopeGuard` to protect against panic in the hash | 
|---|
| 2549 | /// function. | 
|---|
| 2550 | /// | 
|---|
| 2551 | /// # Note | 
|---|
| 2552 | /// | 
|---|
| 2553 | /// It is recommended (but not required): | 
|---|
| 2554 | /// | 
|---|
| 2555 | /// * That the new table's `capacity` be greater than or equal to `self.items`. | 
|---|
| 2556 | /// | 
|---|
| 2557 | /// * The `alloc` is the same [`Allocator`] as the `Allocator` used | 
|---|
| 2558 | ///   to allocate this table. | 
|---|
| 2559 | /// | 
|---|
| 2560 | /// * The `table_layout` is the same [`TableLayout`] as the `TableLayout` used | 
|---|
| 2561 | ///   to allocate this table. | 
|---|
| 2562 | /// | 
|---|
| 2563 | /// If `table_layout` does not match the `TableLayout` that was used to allocate | 
|---|
| 2564 | /// this table, then using `mem::swap` with the `self` and the new table returned | 
|---|
| 2565 | /// by this function results in [`undefined behavior`]. | 
|---|
| 2566 | /// | 
|---|
| 2567 | /// [`undefined behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 2568 | #[ allow(clippy::mut_mut)] | 
|---|
| 2569 | #[ inline] | 
|---|
| 2570 | fn prepare_resize<'a, A>( | 
|---|
| 2571 | &self, | 
|---|
| 2572 | alloc: &'a A, | 
|---|
| 2573 | table_layout: TableLayout, | 
|---|
| 2574 | capacity: usize, | 
|---|
| 2575 | fallibility: Fallibility, | 
|---|
| 2576 | ) -> Result<crate::scopeguard::ScopeGuard<Self, impl FnMut(&mut Self) + 'a>, TryReserveError> | 
|---|
| 2577 | where | 
|---|
| 2578 | A: Allocator, | 
|---|
| 2579 | { | 
|---|
| 2580 | debug_assert!(self.items <= capacity); | 
|---|
| 2581 |  | 
|---|
| 2582 | // Allocate and initialize the new table. | 
|---|
| 2583 | let new_table = | 
|---|
| 2584 | RawTableInner::fallible_with_capacity(alloc, table_layout, capacity, fallibility)?; | 
|---|
| 2585 |  | 
|---|
| 2586 | // The hash function may panic, in which case we simply free the new | 
|---|
| 2587 | // table without dropping any elements that may have been copied into | 
|---|
| 2588 | // it. | 
|---|
| 2589 | // | 
|---|
| 2590 | // This guard is also used to free the old table on success, see | 
|---|
| 2591 | // the comment at the bottom of this function. | 
|---|
| 2592 | Ok(guard(new_table, move |self_| { | 
|---|
| 2593 | if !self_.is_empty_singleton() { | 
|---|
| 2594 | // SAFETY: | 
|---|
| 2595 | // 1. We have checked that our table is allocated. | 
|---|
| 2596 | // 2. We know for sure that the `alloc` and `table_layout` matches the | 
|---|
| 2597 | //    [`Allocator`] and [`TableLayout`] used to allocate this table. | 
|---|
| 2598 | unsafe { self_.free_buckets(alloc, table_layout) }; | 
|---|
| 2599 | } | 
|---|
| 2600 | })) | 
|---|
| 2601 | } | 
|---|
| 2602 |  | 
|---|
| 2603 | /// Reserves or rehashes to make room for `additional` more elements. | 
|---|
| 2604 | /// | 
|---|
| 2605 | /// This uses dynamic dispatch to reduce the amount of | 
|---|
| 2606 | /// code generated, but it is eliminated by LLVM optimizations when inlined. | 
|---|
| 2607 | /// | 
|---|
| 2608 | /// # Safety | 
|---|
| 2609 | /// | 
|---|
| 2610 | /// If any of the following conditions are violated, the result is | 
|---|
| 2611 | /// [`undefined behavior`]: | 
|---|
| 2612 | /// | 
|---|
| 2613 | /// * The `alloc` must be the same [`Allocator`] as the `Allocator` used | 
|---|
| 2614 | ///   to allocate this table. | 
|---|
| 2615 | /// | 
|---|
| 2616 | /// * The `layout` must be the same [`TableLayout`] as the `TableLayout` | 
|---|
| 2617 | ///   used to allocate this table. | 
|---|
| 2618 | /// | 
|---|
| 2619 | /// * The `drop` function (`fn(*mut u8)`) must be the actual drop function of | 
|---|
| 2620 | ///   the elements stored in the table. | 
|---|
| 2621 | /// | 
|---|
| 2622 | /// * The [`RawTableInner`] must have properly initialized control bytes. | 
|---|
| 2623 | /// | 
|---|
| 2624 | /// [`undefined behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 2625 | #[ allow(clippy::inline_always)] | 
|---|
| 2626 | #[ inline(always)] | 
|---|
| 2627 | unsafe fn reserve_rehash_inner<A>( | 
|---|
| 2628 | &mut self, | 
|---|
| 2629 | alloc: &A, | 
|---|
| 2630 | additional: usize, | 
|---|
| 2631 | hasher: &dyn Fn(&mut Self, usize) -> u64, | 
|---|
| 2632 | fallibility: Fallibility, | 
|---|
| 2633 | layout: TableLayout, | 
|---|
| 2634 | drop: Option<unsafe fn(*mut u8)>, | 
|---|
| 2635 | ) -> Result<(), TryReserveError> | 
|---|
| 2636 | where | 
|---|
| 2637 | A: Allocator, | 
|---|
| 2638 | { | 
|---|
| 2639 | // Avoid `Option::ok_or_else` because it bloats LLVM IR. | 
|---|
| 2640 | let new_items = match self.items.checked_add(additional) { | 
|---|
| 2641 | Some(new_items) => new_items, | 
|---|
| 2642 | None => return Err(fallibility.capacity_overflow()), | 
|---|
| 2643 | }; | 
|---|
| 2644 | let full_capacity = bucket_mask_to_capacity(self.bucket_mask); | 
|---|
| 2645 | if new_items <= full_capacity / 2 { | 
|---|
| 2646 | // Rehash in-place without re-allocating if we have plenty of spare | 
|---|
| 2647 | // capacity that is locked up due to DELETED entries. | 
|---|
| 2648 |  | 
|---|
| 2649 | // SAFETY: | 
|---|
| 2650 | // 1. We know for sure that `[`RawTableInner`]` has already been allocated | 
|---|
| 2651 | //    (since new_items <= full_capacity / 2); | 
|---|
| 2652 | // 2. The caller ensures that `drop` function is the actual drop function of | 
|---|
| 2653 | //    the elements stored in the table. | 
|---|
| 2654 | // 3. The caller ensures that `layout` matches the [`TableLayout`] that was | 
|---|
| 2655 | //    used to allocate this table. | 
|---|
| 2656 | // 4. The caller ensures that the control bytes of the `RawTableInner` | 
|---|
| 2657 | //    are already initialized. | 
|---|
| 2658 | self.rehash_in_place(hasher, layout.size, drop); | 
|---|
| 2659 | Ok(()) | 
|---|
| 2660 | } else { | 
|---|
| 2661 | // Otherwise, conservatively resize to at least the next size up | 
|---|
| 2662 | // to avoid churning deletes into frequent rehashes. | 
|---|
| 2663 | // | 
|---|
| 2664 | // SAFETY: | 
|---|
| 2665 | // 1. We know for sure that `capacity >= self.items`. | 
|---|
| 2666 | // 2. The caller ensures that `alloc` and `layout` matches the [`Allocator`] and | 
|---|
| 2667 | //    [`TableLayout`] that were used to allocate this table. | 
|---|
| 2668 | // 3. The caller ensures that the control bytes of the `RawTableInner` | 
|---|
| 2669 | //    are already initialized. | 
|---|
| 2670 | self.resize_inner( | 
|---|
| 2671 | alloc, | 
|---|
| 2672 | usize::max(new_items, full_capacity + 1), | 
|---|
| 2673 | hasher, | 
|---|
| 2674 | fallibility, | 
|---|
| 2675 | layout, | 
|---|
| 2676 | ) | 
|---|
| 2677 | } | 
|---|
| 2678 | } | 
|---|
| 2679 |  | 
|---|
| 2680 | /// Returns an iterator over full buckets indices in the table. | 
|---|
| 2681 | /// | 
|---|
| 2682 | /// # Safety | 
|---|
| 2683 | /// | 
|---|
| 2684 | /// Behavior is undefined if any of the following conditions are violated: | 
|---|
| 2685 | /// | 
|---|
| 2686 | /// * The caller has to ensure that the `RawTableInner` outlives the | 
|---|
| 2687 | ///   `FullBucketsIndices`. Because we cannot make the `next` method | 
|---|
| 2688 | ///   unsafe on the `FullBucketsIndices` struct, we have to make the | 
|---|
| 2689 | ///   `full_buckets_indices` method unsafe. | 
|---|
| 2690 | /// | 
|---|
| 2691 | /// * The [`RawTableInner`] must have properly initialized control bytes. | 
|---|
| 2692 | #[ inline(always)] | 
|---|
| 2693 | unsafe fn full_buckets_indices(&self) -> FullBucketsIndices { | 
|---|
| 2694 | // SAFETY: | 
|---|
| 2695 | // 1. Since the caller of this function ensures that the control bytes | 
|---|
| 2696 | //    are properly initialized and `self.ctrl(0)` points to the start | 
|---|
| 2697 | //    of the array of control bytes, therefore: `ctrl` is valid for reads, | 
|---|
| 2698 | //    properly aligned to `Group::WIDTH` and points to the properly initialized | 
|---|
| 2699 | //    control bytes. | 
|---|
| 2700 | // 2. The value of `items` is equal to the amount of data (values) added | 
|---|
| 2701 | //    to the table. | 
|---|
| 2702 | // | 
|---|
| 2703 | //                         `ctrl` points here (to the start | 
|---|
| 2704 | //                         of the first control byte `CT0`) | 
|---|
| 2705 | //                          ∨ | 
|---|
| 2706 | // [Pad], T_n, ..., T1, T0, |CT0, CT1, ..., CT_n|, Group::WIDTH | 
|---|
| 2707 | //                           \________  ________/ | 
|---|
| 2708 | //                                    \/ | 
|---|
| 2709 | //       `n = buckets - 1`, i.e. `RawTableInner::buckets() - 1` | 
|---|
| 2710 | // | 
|---|
| 2711 | // where: T0...T_n  - our stored data; | 
|---|
| 2712 | //        CT0...CT_n - control bytes or metadata for `data`. | 
|---|
| 2713 | let ctrl = NonNull::new_unchecked(self.ctrl(0).cast::<u8>()); | 
|---|
| 2714 |  | 
|---|
| 2715 | FullBucketsIndices { | 
|---|
| 2716 | // Load the first group | 
|---|
| 2717 | // SAFETY: See explanation above. | 
|---|
| 2718 | current_group: Group::load_aligned(ctrl.as_ptr().cast()) | 
|---|
| 2719 | .match_full() | 
|---|
| 2720 | .into_iter(), | 
|---|
| 2721 | group_first_index: 0, | 
|---|
| 2722 | ctrl, | 
|---|
| 2723 | items: self.items, | 
|---|
| 2724 | } | 
|---|
| 2725 | } | 
|---|
| 2726 |  | 
|---|
| 2727 | /// Allocates a new table of a different size and moves the contents of the | 
|---|
| 2728 | /// current table into it. | 
|---|
| 2729 | /// | 
|---|
| 2730 | /// This uses dynamic dispatch to reduce the amount of | 
|---|
| 2731 | /// code generated, but it is eliminated by LLVM optimizations when inlined. | 
|---|
| 2732 | /// | 
|---|
| 2733 | /// # Safety | 
|---|
| 2734 | /// | 
|---|
| 2735 | /// If any of the following conditions are violated, the result is | 
|---|
| 2736 | /// [`undefined behavior`]: | 
|---|
| 2737 | /// | 
|---|
| 2738 | /// * The `alloc` must be the same [`Allocator`] as the `Allocator` used | 
|---|
| 2739 | ///   to allocate this table; | 
|---|
| 2740 | /// | 
|---|
| 2741 | /// * The `layout` must be the same [`TableLayout`] as the `TableLayout` | 
|---|
| 2742 | ///   used to allocate this table; | 
|---|
| 2743 | /// | 
|---|
| 2744 | /// * The [`RawTableInner`] must have properly initialized control bytes. | 
|---|
| 2745 | /// | 
|---|
| 2746 | /// The caller of this function must ensure that `capacity >= self.items` | 
|---|
| 2747 | /// otherwise: | 
|---|
| 2748 | /// | 
|---|
| 2749 | /// * If `self.items != 0`, calling of this function with `capacity == 0` | 
|---|
| 2750 | ///   results in [`undefined behavior`]. | 
|---|
| 2751 | /// | 
|---|
| 2752 | /// * If `capacity_to_buckets(capacity) < Group::WIDTH` and | 
|---|
| 2753 | ///   `self.items > capacity_to_buckets(capacity)` calling this function | 
|---|
| 2754 | ///   results in [`undefined behavior`]. | 
|---|
| 2755 | /// | 
|---|
| 2756 | /// * If `capacity_to_buckets(capacity) >= Group::WIDTH` and | 
|---|
| 2757 | ///   `self.items > capacity_to_buckets(capacity)` calling this function | 
|---|
| 2758 | ///   are never return (will go into an infinite loop). | 
|---|
| 2759 | /// | 
|---|
| 2760 | /// Note: It is recommended (but not required) that the new table's `capacity` | 
|---|
| 2761 | /// be greater than or equal to `self.items`. In case if `capacity <= self.items` | 
|---|
| 2762 | /// this function can never return. See [`RawTableInner::find_insert_slot`] for | 
|---|
| 2763 | /// more information. | 
|---|
| 2764 | /// | 
|---|
| 2765 | /// [`RawTableInner::find_insert_slot`]: RawTableInner::find_insert_slot | 
|---|
| 2766 | /// [`undefined behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 2767 | #[ allow(clippy::inline_always)] | 
|---|
| 2768 | #[ inline(always)] | 
|---|
| 2769 | unsafe fn resize_inner<A>( | 
|---|
| 2770 | &mut self, | 
|---|
| 2771 | alloc: &A, | 
|---|
| 2772 | capacity: usize, | 
|---|
| 2773 | hasher: &dyn Fn(&mut Self, usize) -> u64, | 
|---|
| 2774 | fallibility: Fallibility, | 
|---|
| 2775 | layout: TableLayout, | 
|---|
| 2776 | ) -> Result<(), TryReserveError> | 
|---|
| 2777 | where | 
|---|
| 2778 | A: Allocator, | 
|---|
| 2779 | { | 
|---|
| 2780 | // SAFETY: We know for sure that `alloc` and `layout` matches the [`Allocator`] and [`TableLayout`] | 
|---|
| 2781 | // that were used to allocate this table. | 
|---|
| 2782 | let mut new_table = self.prepare_resize(alloc, layout, capacity, fallibility)?; | 
|---|
| 2783 |  | 
|---|
| 2784 | // SAFETY: We know for sure that RawTableInner will outlive the | 
|---|
| 2785 | // returned `FullBucketsIndices` iterator, and the caller of this | 
|---|
| 2786 | // function ensures that the control bytes are properly initialized. | 
|---|
| 2787 | for full_byte_index in self.full_buckets_indices() { | 
|---|
| 2788 | // This may panic. | 
|---|
| 2789 | let hash = hasher(self, full_byte_index); | 
|---|
| 2790 |  | 
|---|
| 2791 | // SAFETY: | 
|---|
| 2792 | // We can use a simpler version of insert() here since: | 
|---|
| 2793 | // 1. There are no DELETED entries. | 
|---|
| 2794 | // 2. We know there is enough space in the table. | 
|---|
| 2795 | // 3. All elements are unique. | 
|---|
| 2796 | // 4. The caller of this function guarantees that `capacity > 0` | 
|---|
| 2797 | //    so `new_table` must already have some allocated memory. | 
|---|
| 2798 | // 5. We set `growth_left` and `items` fields of the new table | 
|---|
| 2799 | //    after the loop. | 
|---|
| 2800 | // 6. We insert into the table, at the returned index, the data | 
|---|
| 2801 | //    matching the given hash immediately after calling this function. | 
|---|
| 2802 | let (new_index, _) = new_table.prepare_insert_slot(hash); | 
|---|
| 2803 |  | 
|---|
| 2804 | // SAFETY: | 
|---|
| 2805 | // | 
|---|
| 2806 | // * `src` is valid for reads of `layout.size` bytes, since the | 
|---|
| 2807 | //   table is alive and the `full_byte_index` is guaranteed to be | 
|---|
| 2808 | //   within bounds (see `FullBucketsIndices::next_impl`); | 
|---|
| 2809 | // | 
|---|
| 2810 | // * `dst` is valid for writes of `layout.size` bytes, since the | 
|---|
| 2811 | //   caller ensures that `table_layout` matches the [`TableLayout`] | 
|---|
| 2812 | //   that was used to allocate old table and we have the `new_index` | 
|---|
| 2813 | //   returned by `prepare_insert_slot`. | 
|---|
| 2814 | // | 
|---|
| 2815 | // * Both `src` and `dst` are properly aligned. | 
|---|
| 2816 | // | 
|---|
| 2817 | // * Both `src` and `dst` point to different region of memory. | 
|---|
| 2818 | ptr::copy_nonoverlapping( | 
|---|
| 2819 | self.bucket_ptr(full_byte_index, layout.size), | 
|---|
| 2820 | new_table.bucket_ptr(new_index, layout.size), | 
|---|
| 2821 | layout.size, | 
|---|
| 2822 | ); | 
|---|
| 2823 | } | 
|---|
| 2824 |  | 
|---|
| 2825 | // The hash function didn't panic, so we can safely set the | 
|---|
| 2826 | // `growth_left` and `items` fields of the new table. | 
|---|
| 2827 | new_table.growth_left -= self.items; | 
|---|
| 2828 | new_table.items = self.items; | 
|---|
| 2829 |  | 
|---|
| 2830 | // We successfully copied all elements without panicking. Now replace | 
|---|
| 2831 | // self with the new table. The old table will have its memory freed but | 
|---|
| 2832 | // the items will not be dropped (since they have been moved into the | 
|---|
| 2833 | // new table). | 
|---|
| 2834 | // SAFETY: The caller ensures that `table_layout` matches the [`TableLayout`] | 
|---|
| 2835 | // that was used to allocate this table. | 
|---|
| 2836 | mem::swap(self, &mut new_table); | 
|---|
| 2837 |  | 
|---|
| 2838 | Ok(()) | 
|---|
| 2839 | } | 
|---|
| 2840 |  | 
|---|
| 2841 | /// Rehashes the contents of the table in place (i.e. without changing the | 
|---|
| 2842 | /// allocation). | 
|---|
| 2843 | /// | 
|---|
| 2844 | /// If `hasher` panics then some the table's contents may be lost. | 
|---|
| 2845 | /// | 
|---|
| 2846 | /// This uses dynamic dispatch to reduce the amount of | 
|---|
| 2847 | /// code generated, but it is eliminated by LLVM optimizations when inlined. | 
|---|
| 2848 | /// | 
|---|
| 2849 | /// # Safety | 
|---|
| 2850 | /// | 
|---|
| 2851 | /// If any of the following conditions are violated, the result is [`undefined behavior`]: | 
|---|
| 2852 | /// | 
|---|
| 2853 | /// * The `size_of` must be equal to the size of the elements stored in the table; | 
|---|
| 2854 | /// | 
|---|
| 2855 | /// * The `drop` function (`fn(*mut u8)`) must be the actual drop function of | 
|---|
| 2856 | ///   the elements stored in the table. | 
|---|
| 2857 | /// | 
|---|
| 2858 | /// * The [`RawTableInner`] has already been allocated; | 
|---|
| 2859 | /// | 
|---|
| 2860 | /// * The [`RawTableInner`] must have properly initialized control bytes. | 
|---|
| 2861 | /// | 
|---|
| 2862 | /// [`undefined behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 2863 | #[ allow(clippy::inline_always)] | 
|---|
| 2864 | #[ cfg_attr(feature = "inline-more", inline(always))] | 
|---|
| 2865 | #[ cfg_attr(not(feature = "inline-more"), inline)] | 
|---|
| 2866 | unsafe fn rehash_in_place( | 
|---|
| 2867 | &mut self, | 
|---|
| 2868 | hasher: &dyn Fn(&mut Self, usize) -> u64, | 
|---|
| 2869 | size_of: usize, | 
|---|
| 2870 | drop: Option<unsafe fn(*mut u8)>, | 
|---|
| 2871 | ) { | 
|---|
| 2872 | // If the hash function panics then properly clean up any elements | 
|---|
| 2873 | // that we haven't rehashed yet. We unfortunately can't preserve the | 
|---|
| 2874 | // element since we lost their hash and have no way of recovering it | 
|---|
| 2875 | // without risking another panic. | 
|---|
| 2876 | self.prepare_rehash_in_place(); | 
|---|
| 2877 |  | 
|---|
| 2878 | let mut guard = guard(self, move |self_| { | 
|---|
| 2879 | if let Some(drop) = drop { | 
|---|
| 2880 | for i in 0..self_.buckets() { | 
|---|
| 2881 | if *self_.ctrl(i) == Tag::DELETED { | 
|---|
| 2882 | self_.set_ctrl(i, Tag::EMPTY); | 
|---|
| 2883 | drop(self_.bucket_ptr(i, size_of)); | 
|---|
| 2884 | self_.items -= 1; | 
|---|
| 2885 | } | 
|---|
| 2886 | } | 
|---|
| 2887 | } | 
|---|
| 2888 | self_.growth_left = bucket_mask_to_capacity(self_.bucket_mask) - self_.items; | 
|---|
| 2889 | }); | 
|---|
| 2890 |  | 
|---|
| 2891 | // At this point, DELETED elements are elements that we haven't | 
|---|
| 2892 | // rehashed yet. Find them and re-insert them at their ideal | 
|---|
| 2893 | // position. | 
|---|
| 2894 | 'outer: for i in 0..guard.buckets() { | 
|---|
| 2895 | if *guard.ctrl(i) != Tag::DELETED { | 
|---|
| 2896 | continue; | 
|---|
| 2897 | } | 
|---|
| 2898 |  | 
|---|
| 2899 | let i_p = guard.bucket_ptr(i, size_of); | 
|---|
| 2900 |  | 
|---|
| 2901 | 'inner: loop { | 
|---|
| 2902 | // Hash the current item | 
|---|
| 2903 | let hash = hasher(*guard, i); | 
|---|
| 2904 |  | 
|---|
| 2905 | // Search for a suitable place to put it | 
|---|
| 2906 | // | 
|---|
| 2907 | // SAFETY: Caller of this function ensures that the control bytes | 
|---|
| 2908 | // are properly initialized. | 
|---|
| 2909 | let new_i = guard.find_insert_slot(hash).index; | 
|---|
| 2910 |  | 
|---|
| 2911 | // Probing works by scanning through all of the control | 
|---|
| 2912 | // bytes in groups, which may not be aligned to the group | 
|---|
| 2913 | // size. If both the new and old position fall within the | 
|---|
| 2914 | // same unaligned group, then there is no benefit in moving | 
|---|
| 2915 | // it and we can just continue to the next item. | 
|---|
| 2916 | if likely(guard.is_in_same_group(i, new_i, hash)) { | 
|---|
| 2917 | guard.set_ctrl_hash(i, hash); | 
|---|
| 2918 | continue 'outer; | 
|---|
| 2919 | } | 
|---|
| 2920 |  | 
|---|
| 2921 | let new_i_p = guard.bucket_ptr(new_i, size_of); | 
|---|
| 2922 |  | 
|---|
| 2923 | // We are moving the current item to a new position. Write | 
|---|
| 2924 | // our H2 to the control byte of the new position. | 
|---|
| 2925 | let prev_ctrl = guard.replace_ctrl_hash(new_i, hash); | 
|---|
| 2926 | if prev_ctrl == Tag::EMPTY { | 
|---|
| 2927 | guard.set_ctrl(i, Tag::EMPTY); | 
|---|
| 2928 | // If the target slot is empty, simply move the current | 
|---|
| 2929 | // element into the new slot and clear the old control | 
|---|
| 2930 | // byte. | 
|---|
| 2931 | ptr::copy_nonoverlapping(i_p, new_i_p, size_of); | 
|---|
| 2932 | continue 'outer; | 
|---|
| 2933 | } else { | 
|---|
| 2934 | // If the target slot is occupied, swap the two elements | 
|---|
| 2935 | // and then continue processing the element that we just | 
|---|
| 2936 | // swapped into the old slot. | 
|---|
| 2937 | debug_assert_eq!(prev_ctrl, Tag::DELETED); | 
|---|
| 2938 | ptr::swap_nonoverlapping(i_p, new_i_p, size_of); | 
|---|
| 2939 | continue 'inner; | 
|---|
| 2940 | } | 
|---|
| 2941 | } | 
|---|
| 2942 | } | 
|---|
| 2943 |  | 
|---|
| 2944 | guard.growth_left = bucket_mask_to_capacity(guard.bucket_mask) - guard.items; | 
|---|
| 2945 |  | 
|---|
| 2946 | mem::forget(guard); | 
|---|
| 2947 | } | 
|---|
| 2948 |  | 
|---|
| 2949 | /// Deallocates the table without dropping any entries. | 
|---|
| 2950 | /// | 
|---|
| 2951 | /// # Note | 
|---|
| 2952 | /// | 
|---|
| 2953 | /// This function must be called only after [`drop_elements`](RawTableInner::drop_elements), | 
|---|
| 2954 | /// else it can lead to leaking of memory. Also calling this function automatically | 
|---|
| 2955 | /// makes invalid (dangling) all instances of buckets ([`Bucket`]) and makes invalid | 
|---|
| 2956 | /// (dangling) the `ctrl` field of the table. | 
|---|
| 2957 | /// | 
|---|
| 2958 | /// # Safety | 
|---|
| 2959 | /// | 
|---|
| 2960 | /// If any of the following conditions are violated, the result is [`Undefined Behavior`]: | 
|---|
| 2961 | /// | 
|---|
| 2962 | /// * The [`RawTableInner`] has already been allocated; | 
|---|
| 2963 | /// | 
|---|
| 2964 | /// * The `alloc` must be the same [`Allocator`] as the `Allocator` that was used | 
|---|
| 2965 | ///   to allocate this table. | 
|---|
| 2966 | /// | 
|---|
| 2967 | /// * The `table_layout` must be the same [`TableLayout`] as the `TableLayout` that was used | 
|---|
| 2968 | ///   to allocate this table. | 
|---|
| 2969 | /// | 
|---|
| 2970 | /// See also [`GlobalAlloc::dealloc`] or [`Allocator::deallocate`] for more  information. | 
|---|
| 2971 | /// | 
|---|
| 2972 | /// [`Undefined Behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 2973 | /// [`GlobalAlloc::dealloc`]: https://doc.rust-lang.org/alloc/alloc/trait.GlobalAlloc.html#tymethod.dealloc | 
|---|
| 2974 | /// [`Allocator::deallocate`]: https://doc.rust-lang.org/alloc/alloc/trait.Allocator.html#tymethod.deallocate | 
|---|
| 2975 | #[ inline] | 
|---|
| 2976 | unsafe fn free_buckets<A>(&mut self, alloc: &A, table_layout: TableLayout) | 
|---|
| 2977 | where | 
|---|
| 2978 | A: Allocator, | 
|---|
| 2979 | { | 
|---|
| 2980 | // SAFETY: The caller must uphold the safety contract for `free_buckets` | 
|---|
| 2981 | // method. | 
|---|
| 2982 | let (ptr, layout) = self.allocation_info(table_layout); | 
|---|
| 2983 | alloc.deallocate(ptr, layout); | 
|---|
| 2984 | } | 
|---|
| 2985 |  | 
|---|
| 2986 | /// Returns a pointer to the allocated memory and the layout that was used to | 
|---|
| 2987 | /// allocate the table. | 
|---|
| 2988 | /// | 
|---|
| 2989 | /// # Safety | 
|---|
| 2990 | /// | 
|---|
| 2991 | /// Caller of this function must observe the following safety rules: | 
|---|
| 2992 | /// | 
|---|
| 2993 | /// * The [`RawTableInner`] has already been allocated, otherwise | 
|---|
| 2994 | ///   calling this function results in [`undefined behavior`] | 
|---|
| 2995 | /// | 
|---|
| 2996 | /// * The `table_layout` must be the same [`TableLayout`] as the `TableLayout` | 
|---|
| 2997 | ///   that was used to allocate this table. Failure to comply with this condition | 
|---|
| 2998 | ///   may result in [`undefined behavior`]. | 
|---|
| 2999 | /// | 
|---|
| 3000 | /// See also [`GlobalAlloc::dealloc`] or [`Allocator::deallocate`] for more  information. | 
|---|
| 3001 | /// | 
|---|
| 3002 | /// [`undefined behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 3003 | /// [`GlobalAlloc::dealloc`]: https://doc.rust-lang.org/alloc/alloc/trait.GlobalAlloc.html#tymethod.dealloc | 
|---|
| 3004 | /// [`Allocator::deallocate`]: https://doc.rust-lang.org/alloc/alloc/trait.Allocator.html#tymethod.deallocate | 
|---|
| 3005 | #[ inline] | 
|---|
| 3006 | unsafe fn allocation_info(&self, table_layout: TableLayout) -> (NonNull<u8>, Layout) { | 
|---|
| 3007 | debug_assert!( | 
|---|
| 3008 | !self.is_empty_singleton(), | 
|---|
| 3009 | "this function can only be called on non-empty tables" | 
|---|
| 3010 | ); | 
|---|
| 3011 |  | 
|---|
| 3012 | // Avoid `Option::unwrap_or_else` because it bloats LLVM IR. | 
|---|
| 3013 | let (layout, ctrl_offset) = match table_layout.calculate_layout_for(self.buckets()) { | 
|---|
| 3014 | Some(lco) => lco, | 
|---|
| 3015 | None => unsafe { hint::unreachable_unchecked() }, | 
|---|
| 3016 | }; | 
|---|
| 3017 | ( | 
|---|
| 3018 | // SAFETY: The caller must uphold the safety contract for `allocation_info` method. | 
|---|
| 3019 | unsafe { NonNull::new_unchecked(self.ctrl.as_ptr().sub(ctrl_offset)) }, | 
|---|
| 3020 | layout, | 
|---|
| 3021 | ) | 
|---|
| 3022 | } | 
|---|
| 3023 |  | 
|---|
| 3024 | /// Returns the total amount of memory allocated internally by the hash | 
|---|
| 3025 | /// table, in bytes. | 
|---|
| 3026 | /// | 
|---|
| 3027 | /// The returned number is informational only. It is intended to be | 
|---|
| 3028 | /// primarily used for memory profiling. | 
|---|
| 3029 | /// | 
|---|
| 3030 | /// # Safety | 
|---|
| 3031 | /// | 
|---|
| 3032 | /// The `table_layout` must be the same [`TableLayout`] as the `TableLayout` | 
|---|
| 3033 | /// that was used to allocate this table. Failure to comply with this condition | 
|---|
| 3034 | /// may result in [`undefined behavior`]. | 
|---|
| 3035 | /// | 
|---|
| 3036 | /// | 
|---|
| 3037 | /// [`undefined behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 3038 | #[ inline] | 
|---|
| 3039 | unsafe fn allocation_size_or_zero(&self, table_layout: TableLayout) -> usize { | 
|---|
| 3040 | if self.is_empty_singleton() { | 
|---|
| 3041 | 0 | 
|---|
| 3042 | } else { | 
|---|
| 3043 | // SAFETY: | 
|---|
| 3044 | // 1. We have checked that our table is allocated. | 
|---|
| 3045 | // 2. The caller ensures that `table_layout` matches the [`TableLayout`] | 
|---|
| 3046 | // that was used to allocate this table. | 
|---|
| 3047 | unsafe { self.allocation_info(table_layout).1.size() } | 
|---|
| 3048 | } | 
|---|
| 3049 | } | 
|---|
| 3050 |  | 
|---|
| 3051 | /// Marks all table buckets as empty without dropping their contents. | 
|---|
| 3052 | #[ inline] | 
|---|
| 3053 | fn clear_no_drop(&mut self) { | 
|---|
| 3054 | if !self.is_empty_singleton() { | 
|---|
| 3055 | self.ctrl_slice().fill_empty(); | 
|---|
| 3056 | } | 
|---|
| 3057 | self.items = 0; | 
|---|
| 3058 | self.growth_left = bucket_mask_to_capacity(self.bucket_mask); | 
|---|
| 3059 | } | 
|---|
| 3060 |  | 
|---|
| 3061 | /// Erases the [`Bucket`]'s control byte at the given index so that it does not | 
|---|
| 3062 | /// triggered as full, decreases the `items` of the table and, if it can be done, | 
|---|
| 3063 | /// increases `self.growth_left`. | 
|---|
| 3064 | /// | 
|---|
| 3065 | /// This function does not actually erase / drop the [`Bucket`] itself, i.e. it | 
|---|
| 3066 | /// does not make any changes to the `data` parts of the table. The caller of this | 
|---|
| 3067 | /// function must take care to properly drop the `data`, otherwise calling this | 
|---|
| 3068 | /// function may result in a memory leak. | 
|---|
| 3069 | /// | 
|---|
| 3070 | /// # Safety | 
|---|
| 3071 | /// | 
|---|
| 3072 | /// You must observe the following safety rules when calling this function: | 
|---|
| 3073 | /// | 
|---|
| 3074 | /// * The [`RawTableInner`] has already been allocated; | 
|---|
| 3075 | /// | 
|---|
| 3076 | /// * It must be the full control byte at the given position; | 
|---|
| 3077 | /// | 
|---|
| 3078 | /// * The `index` must not be greater than the `RawTableInner.bucket_mask`, i.e. | 
|---|
| 3079 | ///   `index <= RawTableInner.bucket_mask` or, in other words, `(index + 1)` must | 
|---|
| 3080 | ///   be no greater than the number returned by the function [`RawTableInner::buckets`]. | 
|---|
| 3081 | /// | 
|---|
| 3082 | /// Calling this function on a table that has not been allocated results in [`undefined behavior`]. | 
|---|
| 3083 | /// | 
|---|
| 3084 | /// Calling this function on a table with no elements is unspecified, but calling subsequent | 
|---|
| 3085 | /// functions is likely to result in [`undefined behavior`] due to overflow subtraction | 
|---|
| 3086 | /// (`self.items -= 1 cause overflow when self.items == 0`). | 
|---|
| 3087 | /// | 
|---|
| 3088 | /// See also [`Bucket::as_ptr`] method, for more information about of properly removing | 
|---|
| 3089 | /// or saving `data element` from / into the [`RawTable`] / [`RawTableInner`]. | 
|---|
| 3090 | /// | 
|---|
| 3091 | /// [`RawTableInner::buckets`]: RawTableInner::buckets | 
|---|
| 3092 | /// [`Bucket::as_ptr`]: Bucket::as_ptr | 
|---|
| 3093 | /// [`undefined behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 3094 | #[ inline] | 
|---|
| 3095 | unsafe fn erase(&mut self, index: usize) { | 
|---|
| 3096 | debug_assert!(self.is_bucket_full(index)); | 
|---|
| 3097 |  | 
|---|
| 3098 | // This is the same as `index.wrapping_sub(Group::WIDTH) % self.buckets()` because | 
|---|
| 3099 | // the number of buckets is a power of two, and `self.bucket_mask = self.buckets() - 1`. | 
|---|
| 3100 | let index_before = index.wrapping_sub(Group::WIDTH) & self.bucket_mask; | 
|---|
| 3101 | // SAFETY: | 
|---|
| 3102 | // - The caller must uphold the safety contract for `erase` method; | 
|---|
| 3103 | // - `index_before` is guaranteed to be in range due to masking with `self.bucket_mask` | 
|---|
| 3104 | let empty_before = Group::load(self.ctrl(index_before)).match_empty(); | 
|---|
| 3105 | let empty_after = Group::load(self.ctrl(index)).match_empty(); | 
|---|
| 3106 |  | 
|---|
| 3107 | // Inserting and searching in the map is performed by two key functions: | 
|---|
| 3108 | // | 
|---|
| 3109 | // - The `find_insert_slot` function that looks up the index of any `Tag::EMPTY` or `Tag::DELETED` | 
|---|
| 3110 | //   slot in a group to be able to insert. If it doesn't find an `Tag::EMPTY` or `Tag::DELETED` | 
|---|
| 3111 | //   slot immediately in the first group, it jumps to the next `Group` looking for it, | 
|---|
| 3112 | //   and so on until it has gone through all the groups in the control bytes. | 
|---|
| 3113 | // | 
|---|
| 3114 | // - The `find_inner` function that looks for the index of the desired element by looking | 
|---|
| 3115 | //   at all the `FULL` bytes in the group. If it did not find the element right away, and | 
|---|
| 3116 | //   there is no `Tag::EMPTY` byte in the group, then this means that the `find_insert_slot` | 
|---|
| 3117 | //   function may have found a suitable slot in the next group. Therefore, `find_inner` | 
|---|
| 3118 | //   jumps further, and if it does not find the desired element and again there is no `Tag::EMPTY` | 
|---|
| 3119 | //   byte, then it jumps further, and so on. The search stops only if `find_inner` function | 
|---|
| 3120 | //   finds the desired element or hits an `Tag::EMPTY` slot/byte. | 
|---|
| 3121 | // | 
|---|
| 3122 | // Accordingly, this leads to two consequences: | 
|---|
| 3123 | // | 
|---|
| 3124 | // - The map must have `Tag::EMPTY` slots (bytes); | 
|---|
| 3125 | // | 
|---|
| 3126 | // - You can't just mark the byte to be erased as `Tag::EMPTY`, because otherwise the `find_inner` | 
|---|
| 3127 | //   function may stumble upon an `Tag::EMPTY` byte before finding the desired element and stop | 
|---|
| 3128 | //   searching. | 
|---|
| 3129 | // | 
|---|
| 3130 | // Thus it is necessary to check all bytes after and before the erased element. If we are in | 
|---|
| 3131 | // a contiguous `Group` of `FULL` or `Tag::DELETED` bytes (the number of `FULL` or `Tag::DELETED` bytes | 
|---|
| 3132 | // before and after is greater than or equal to `Group::WIDTH`), then we must mark our byte as | 
|---|
| 3133 | // `Tag::DELETED` in order for the `find_inner` function to go further. On the other hand, if there | 
|---|
| 3134 | // is at least one `Tag::EMPTY` slot in the `Group`, then the `find_inner` function will still stumble | 
|---|
| 3135 | // upon an `Tag::EMPTY` byte, so we can safely mark our erased byte as `Tag::EMPTY` as well. | 
|---|
| 3136 | // | 
|---|
| 3137 | // Finally, since `index_before == (index.wrapping_sub(Group::WIDTH) & self.bucket_mask) == index` | 
|---|
| 3138 | // and given all of the above, tables smaller than the group width (self.buckets() < Group::WIDTH) | 
|---|
| 3139 | // cannot have `Tag::DELETED` bytes. | 
|---|
| 3140 | // | 
|---|
| 3141 | // Note that in this context `leading_zeros` refers to the bytes at the end of a group, while | 
|---|
| 3142 | // `trailing_zeros` refers to the bytes at the beginning of a group. | 
|---|
| 3143 | let ctrl = if empty_before.leading_zeros() + empty_after.trailing_zeros() >= Group::WIDTH { | 
|---|
| 3144 | Tag::DELETED | 
|---|
| 3145 | } else { | 
|---|
| 3146 | self.growth_left += 1; | 
|---|
| 3147 | Tag::EMPTY | 
|---|
| 3148 | }; | 
|---|
| 3149 | // SAFETY: the caller must uphold the safety contract for `erase` method. | 
|---|
| 3150 | self.set_ctrl(index, ctrl); | 
|---|
| 3151 | self.items -= 1; | 
|---|
| 3152 | } | 
|---|
| 3153 | } | 
|---|
| 3154 |  | 
|---|
| 3155 | impl<T: Clone, A: Allocator + Clone> Clone for RawTable<T, A> { | 
|---|
| 3156 | fn clone(&self) -> Self { | 
|---|
| 3157 | if self.table.is_empty_singleton() { | 
|---|
| 3158 | Self::new_in(self.alloc.clone()) | 
|---|
| 3159 | } else { | 
|---|
| 3160 | unsafe { | 
|---|
| 3161 | // Avoid `Result::ok_or_else` because it bloats LLVM IR. | 
|---|
| 3162 | // | 
|---|
| 3163 | // SAFETY: This is safe as we are taking the size of an already allocated table | 
|---|
| 3164 | // and therefore capacity overflow cannot occur, `self.table.buckets()` is power | 
|---|
| 3165 | // of two and all allocator errors will be caught inside `RawTableInner::new_uninitialized`. | 
|---|
| 3166 | let mut new_table = match Self::new_uninitialized( | 
|---|
| 3167 | self.alloc.clone(), | 
|---|
| 3168 | self.table.buckets(), | 
|---|
| 3169 | Fallibility::Infallible, | 
|---|
| 3170 | ) { | 
|---|
| 3171 | Ok(table) => table, | 
|---|
| 3172 | Err(_) => hint::unreachable_unchecked(), | 
|---|
| 3173 | }; | 
|---|
| 3174 |  | 
|---|
| 3175 | // Cloning elements may fail (the clone function may panic). But we don't | 
|---|
| 3176 | // need to worry about uninitialized control bits, since: | 
|---|
| 3177 | // 1. The number of items (elements) in the table is zero, which means that | 
|---|
| 3178 | //    the control bits will not be read by Drop function. | 
|---|
| 3179 | // 2. The `clone_from_spec` method will first copy all control bits from | 
|---|
| 3180 | //    `self` (thus initializing them). But this will not affect the `Drop` | 
|---|
| 3181 | //    function, since the `clone_from_spec` function sets `items` only after | 
|---|
| 3182 | //    successfully cloning all elements. | 
|---|
| 3183 | new_table.clone_from_spec(self); | 
|---|
| 3184 | new_table | 
|---|
| 3185 | } | 
|---|
| 3186 | } | 
|---|
| 3187 | } | 
|---|
| 3188 |  | 
|---|
| 3189 | fn clone_from(&mut self, source: &Self) { | 
|---|
| 3190 | if source.table.is_empty_singleton() { | 
|---|
| 3191 | let mut old_inner = mem::replace(&mut self.table, RawTableInner::NEW); | 
|---|
| 3192 | unsafe { | 
|---|
| 3193 | // SAFETY: | 
|---|
| 3194 | // 1. We call the function only once; | 
|---|
| 3195 | // 2. We know for sure that `alloc` and `table_layout` matches the [`Allocator`] | 
|---|
| 3196 | //    and [`TableLayout`] that were used to allocate this table. | 
|---|
| 3197 | // 3. If any elements' drop function panics, then there will only be a memory leak, | 
|---|
| 3198 | //    because we have replaced the inner table with a new one. | 
|---|
| 3199 | old_inner.drop_inner_table::<T, _>(&self.alloc, Self::TABLE_LAYOUT); | 
|---|
| 3200 | } | 
|---|
| 3201 | } else { | 
|---|
| 3202 | unsafe { | 
|---|
| 3203 | // Make sure that if any panics occurs, we clear the table and | 
|---|
| 3204 | // leave it in an empty state. | 
|---|
| 3205 | let mut self_ = guard(self, |self_| { | 
|---|
| 3206 | self_.clear_no_drop(); | 
|---|
| 3207 | }); | 
|---|
| 3208 |  | 
|---|
| 3209 | // First, drop all our elements without clearing the control | 
|---|
| 3210 | // bytes. If this panics then the scope guard will clear the | 
|---|
| 3211 | // table, leaking any elements that were not dropped yet. | 
|---|
| 3212 | // | 
|---|
| 3213 | // This leak is unavoidable: we can't try dropping more elements | 
|---|
| 3214 | // since this could lead to another panic and abort the process. | 
|---|
| 3215 | // | 
|---|
| 3216 | // SAFETY: If something gets wrong we clear our table right after | 
|---|
| 3217 | // dropping the elements, so there is no double drop, since `items` | 
|---|
| 3218 | // will be equal to zero. | 
|---|
| 3219 | self_.table.drop_elements::<T>(); | 
|---|
| 3220 |  | 
|---|
| 3221 | // If necessary, resize our table to match the source. | 
|---|
| 3222 | if self_.buckets() != source.buckets() { | 
|---|
| 3223 | let new_inner = match RawTableInner::new_uninitialized( | 
|---|
| 3224 | &self_.alloc, | 
|---|
| 3225 | Self::TABLE_LAYOUT, | 
|---|
| 3226 | source.buckets(), | 
|---|
| 3227 | Fallibility::Infallible, | 
|---|
| 3228 | ) { | 
|---|
| 3229 | Ok(table) => table, | 
|---|
| 3230 | Err(_) => hint::unreachable_unchecked(), | 
|---|
| 3231 | }; | 
|---|
| 3232 | // Replace the old inner with new uninitialized one. It's ok, since if something gets | 
|---|
| 3233 | // wrong `ScopeGuard` will initialize all control bytes and leave empty table. | 
|---|
| 3234 | let mut old_inner = mem::replace(&mut self_.table, new_inner); | 
|---|
| 3235 | if !old_inner.is_empty_singleton() { | 
|---|
| 3236 | // SAFETY: | 
|---|
| 3237 | // 1. We have checked that our table is allocated. | 
|---|
| 3238 | // 2. We know for sure that `alloc` and `table_layout` matches | 
|---|
| 3239 | // the [`Allocator`] and [`TableLayout`] that were used to allocate this table. | 
|---|
| 3240 | old_inner.free_buckets(&self_.alloc, Self::TABLE_LAYOUT); | 
|---|
| 3241 | } | 
|---|
| 3242 | } | 
|---|
| 3243 |  | 
|---|
| 3244 | // Cloning elements may fail (the clone function may panic), but the `ScopeGuard` | 
|---|
| 3245 | // inside the `clone_from_impl` function will take care of that, dropping all | 
|---|
| 3246 | // cloned elements if necessary. Our `ScopeGuard` will clear the table. | 
|---|
| 3247 | self_.clone_from_spec(source); | 
|---|
| 3248 |  | 
|---|
| 3249 | // Disarm the scope guard if cloning was successful. | 
|---|
| 3250 | ScopeGuard::into_inner(self_); | 
|---|
| 3251 | } | 
|---|
| 3252 | } | 
|---|
| 3253 | } | 
|---|
| 3254 | } | 
|---|
| 3255 |  | 
|---|
| 3256 | /// Specialization of `clone_from` for `Copy` types | 
|---|
| 3257 | trait RawTableClone { | 
|---|
| 3258 | unsafe fn clone_from_spec(&mut self, source: &Self); | 
|---|
| 3259 | } | 
|---|
| 3260 | impl<T: Clone, A: Allocator + Clone> RawTableClone for RawTable<T, A> { | 
|---|
| 3261 | default_fn! { | 
|---|
| 3262 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 3263 | unsafe fn clone_from_spec(&mut self, source: &Self) { | 
|---|
| 3264 | self.clone_from_impl(source); | 
|---|
| 3265 | } | 
|---|
| 3266 | } | 
|---|
| 3267 | } | 
|---|
| 3268 | #[ cfg(feature = "nightly")] | 
|---|
| 3269 | impl<T: Copy, A: Allocator + Clone> RawTableClone for RawTable<T, A> { | 
|---|
| 3270 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 3271 | unsafe fn clone_from_spec(&mut self, source: &Self) { | 
|---|
| 3272 | source | 
|---|
| 3273 | .table | 
|---|
| 3274 | .ctrl(0) | 
|---|
| 3275 | .copy_to_nonoverlapping(self.table.ctrl(0), self.table.num_ctrl_bytes()); | 
|---|
| 3276 | source | 
|---|
| 3277 | .data_start() | 
|---|
| 3278 | .as_ptr() | 
|---|
| 3279 | .copy_to_nonoverlapping(self.data_start().as_ptr(), self.table.buckets()); | 
|---|
| 3280 |  | 
|---|
| 3281 | self.table.items = source.table.items; | 
|---|
| 3282 | self.table.growth_left = source.table.growth_left; | 
|---|
| 3283 | } | 
|---|
| 3284 | } | 
|---|
| 3285 |  | 
|---|
| 3286 | impl<T: Clone, A: Allocator + Clone> RawTable<T, A> { | 
|---|
| 3287 | /// Common code for `clone` and `clone_from`. Assumes: | 
|---|
| 3288 | /// - `self.buckets() == source.buckets()`. | 
|---|
| 3289 | /// - Any existing elements have been dropped. | 
|---|
| 3290 | /// - The control bytes are not initialized yet. | 
|---|
| 3291 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 3292 | unsafe fn clone_from_impl(&mut self, source: &Self) { | 
|---|
| 3293 | // Copy the control bytes unchanged. We do this in a single pass | 
|---|
| 3294 | source | 
|---|
| 3295 | .table | 
|---|
| 3296 | .ctrl(0) | 
|---|
| 3297 | .copy_to_nonoverlapping(self.table.ctrl(0), self.table.num_ctrl_bytes()); | 
|---|
| 3298 |  | 
|---|
| 3299 | // The cloning of elements may panic, in which case we need | 
|---|
| 3300 | // to make sure we drop only the elements that have been | 
|---|
| 3301 | // cloned so far. | 
|---|
| 3302 | let mut guard = guard((0, &mut *self), |(index, self_)| { | 
|---|
| 3303 | if T::NEEDS_DROP { | 
|---|
| 3304 | for i in 0..*index { | 
|---|
| 3305 | if self_.is_bucket_full(i) { | 
|---|
| 3306 | self_.bucket(i).drop(); | 
|---|
| 3307 | } | 
|---|
| 3308 | } | 
|---|
| 3309 | } | 
|---|
| 3310 | }); | 
|---|
| 3311 |  | 
|---|
| 3312 | for from in source.iter() { | 
|---|
| 3313 | let index = source.bucket_index(&from); | 
|---|
| 3314 | let to = guard.1.bucket(index); | 
|---|
| 3315 | to.write(from.as_ref().clone()); | 
|---|
| 3316 |  | 
|---|
| 3317 | // Update the index in case we need to unwind. | 
|---|
| 3318 | guard.0 = index + 1; | 
|---|
| 3319 | } | 
|---|
| 3320 |  | 
|---|
| 3321 | // Successfully cloned all items, no need to clean up. | 
|---|
| 3322 | mem::forget(guard); | 
|---|
| 3323 |  | 
|---|
| 3324 | self.table.items = source.table.items; | 
|---|
| 3325 | self.table.growth_left = source.table.growth_left; | 
|---|
| 3326 | } | 
|---|
| 3327 | } | 
|---|
| 3328 |  | 
|---|
| 3329 | impl<T, A: Allocator + Default> Default for RawTable<T, A> { | 
|---|
| 3330 | #[ inline] | 
|---|
| 3331 | fn default() -> Self { | 
|---|
| 3332 | Self::new_in(alloc:Default::default()) | 
|---|
| 3333 | } | 
|---|
| 3334 | } | 
|---|
| 3335 |  | 
|---|
| 3336 | #[ cfg(feature = "nightly")] | 
|---|
| 3337 | unsafe impl<#[ may_dangle] T, A: Allocator> Drop for RawTable<T, A> { | 
|---|
| 3338 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 3339 | fn drop(&mut self) { | 
|---|
| 3340 | unsafe { | 
|---|
| 3341 | // SAFETY: | 
|---|
| 3342 | // 1. We call the function only once; | 
|---|
| 3343 | // 2. We know for sure that `alloc` and `table_layout` matches the [`Allocator`] | 
|---|
| 3344 | //    and [`TableLayout`] that were used to allocate this table. | 
|---|
| 3345 | // 3. If the drop function of any elements fails, then only a memory leak will occur, | 
|---|
| 3346 | //    and we don't care because we are inside the `Drop` function of the `RawTable`, | 
|---|
| 3347 | //    so there won't be any table left in an inconsistent state. | 
|---|
| 3348 | self.table | 
|---|
| 3349 | .drop_inner_table::<T, _>(&self.alloc, Self::TABLE_LAYOUT); | 
|---|
| 3350 | } | 
|---|
| 3351 | } | 
|---|
| 3352 | } | 
|---|
| 3353 | #[ cfg(not(feature = "nightly"))] | 
|---|
| 3354 | impl<T, A: Allocator> Drop for RawTable<T, A> { | 
|---|
| 3355 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 3356 | fn drop(&mut self) { | 
|---|
| 3357 | unsafe { | 
|---|
| 3358 | // SAFETY: | 
|---|
| 3359 | // 1. We call the function only once; | 
|---|
| 3360 | // 2. We know for sure that `alloc` and `table_layout` matches the [`Allocator`] | 
|---|
| 3361 | //    and [`TableLayout`] that were used to allocate this table. | 
|---|
| 3362 | // 3. If the drop function of any elements fails, then only a memory leak will occur, | 
|---|
| 3363 | //    and we don't care because we are inside the `Drop` function of the `RawTable`, | 
|---|
| 3364 | //    so there won't be any table left in an inconsistent state. | 
|---|
| 3365 | self.table | 
|---|
| 3366 | .drop_inner_table::<T, _>(&self.alloc, Self::TABLE_LAYOUT); | 
|---|
| 3367 | } | 
|---|
| 3368 | } | 
|---|
| 3369 | } | 
|---|
| 3370 |  | 
|---|
| 3371 | impl<T, A: Allocator> IntoIterator for RawTable<T, A> { | 
|---|
| 3372 | type Item = T; | 
|---|
| 3373 | type IntoIter = RawIntoIter<T, A>; | 
|---|
| 3374 |  | 
|---|
| 3375 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 3376 | fn into_iter(self) -> RawIntoIter<T, A> { | 
|---|
| 3377 | unsafe { | 
|---|
| 3378 | let iter: RawIter = self.iter(); | 
|---|
| 3379 | self.into_iter_from(iter) | 
|---|
| 3380 | } | 
|---|
| 3381 | } | 
|---|
| 3382 | } | 
|---|
| 3383 |  | 
|---|
| 3384 | /// Iterator over a sub-range of a table. Unlike `RawIter` this iterator does | 
|---|
| 3385 | /// not track an item count. | 
|---|
| 3386 | pub(crate) struct RawIterRange<T> { | 
|---|
| 3387 | // Mask of full buckets in the current group. Bits are cleared from this | 
|---|
| 3388 | // mask as each element is processed. | 
|---|
| 3389 | current_group: BitMaskIter, | 
|---|
| 3390 |  | 
|---|
| 3391 | // Pointer to the buckets for the current group. | 
|---|
| 3392 | data: Bucket<T>, | 
|---|
| 3393 |  | 
|---|
| 3394 | // Pointer to the next group of control bytes, | 
|---|
| 3395 | // Must be aligned to the group size. | 
|---|
| 3396 | next_ctrl: *const u8, | 
|---|
| 3397 |  | 
|---|
| 3398 | // Pointer one past the last control byte of this range. | 
|---|
| 3399 | end: *const u8, | 
|---|
| 3400 | } | 
|---|
| 3401 |  | 
|---|
| 3402 | impl<T> RawIterRange<T> { | 
|---|
| 3403 | /// Returns a `RawIterRange` covering a subset of a table. | 
|---|
| 3404 | /// | 
|---|
| 3405 | /// # Safety | 
|---|
| 3406 | /// | 
|---|
| 3407 | /// If any of the following conditions are violated, the result is | 
|---|
| 3408 | /// [`undefined behavior`]: | 
|---|
| 3409 | /// | 
|---|
| 3410 | /// * `ctrl` must be [valid] for reads, i.e. table outlives the `RawIterRange`; | 
|---|
| 3411 | /// | 
|---|
| 3412 | /// * `ctrl` must be properly aligned to the group size (`Group::WIDTH`); | 
|---|
| 3413 | /// | 
|---|
| 3414 | /// * `ctrl` must point to the array of properly initialized control bytes; | 
|---|
| 3415 | /// | 
|---|
| 3416 | /// * `data` must be the [`Bucket`] at the `ctrl` index in the table; | 
|---|
| 3417 | /// | 
|---|
| 3418 | /// * the value of `len` must be less than or equal to the number of table buckets, | 
|---|
| 3419 | ///   and the returned value of `ctrl.as_ptr().add(len).offset_from(ctrl.as_ptr())` | 
|---|
| 3420 | ///   must be positive. | 
|---|
| 3421 | /// | 
|---|
| 3422 | /// * The `ctrl.add(len)` pointer must be either in bounds or one | 
|---|
| 3423 | ///   byte past the end of the same [allocated table]. | 
|---|
| 3424 | /// | 
|---|
| 3425 | /// * The `len` must be a power of two. | 
|---|
| 3426 | /// | 
|---|
| 3427 | /// [valid]: https://doc.rust-lang.org/std/ptr/index.html#safety | 
|---|
| 3428 | /// [`undefined behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 3429 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 3430 | unsafe fn new(ctrl: *const u8, data: Bucket<T>, len: usize) -> Self { | 
|---|
| 3431 | debug_assert_ne!(len, 0); | 
|---|
| 3432 | debug_assert_eq!(ctrl as usize % Group::WIDTH, 0); | 
|---|
| 3433 | // SAFETY: The caller must uphold the safety rules for the [`RawIterRange::new`] | 
|---|
| 3434 | let end = ctrl.add(len); | 
|---|
| 3435 |  | 
|---|
| 3436 | // Load the first group and advance ctrl to point to the next group | 
|---|
| 3437 | // SAFETY: The caller must uphold the safety rules for the [`RawIterRange::new`] | 
|---|
| 3438 | let current_group = Group::load_aligned(ctrl.cast()).match_full(); | 
|---|
| 3439 | let next_ctrl = ctrl.add(Group::WIDTH); | 
|---|
| 3440 |  | 
|---|
| 3441 | Self { | 
|---|
| 3442 | current_group: current_group.into_iter(), | 
|---|
| 3443 | data, | 
|---|
| 3444 | next_ctrl, | 
|---|
| 3445 | end, | 
|---|
| 3446 | } | 
|---|
| 3447 | } | 
|---|
| 3448 |  | 
|---|
| 3449 | /// Splits a `RawIterRange` into two halves. | 
|---|
| 3450 | /// | 
|---|
| 3451 | /// Returns `None` if the remaining range is smaller than or equal to the | 
|---|
| 3452 | /// group width. | 
|---|
| 3453 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 3454 | #[ cfg(feature = "rayon")] | 
|---|
| 3455 | pub(crate) fn split(mut self) -> (Self, Option<RawIterRange<T>>) { | 
|---|
| 3456 | unsafe { | 
|---|
| 3457 | if self.end <= self.next_ctrl { | 
|---|
| 3458 | // Nothing to split if the group that we are current processing | 
|---|
| 3459 | // is the last one. | 
|---|
| 3460 | (self, None) | 
|---|
| 3461 | } else { | 
|---|
| 3462 | // len is the remaining number of elements after the group that | 
|---|
| 3463 | // we are currently processing. It must be a multiple of the | 
|---|
| 3464 | // group size (small tables are caught by the check above). | 
|---|
| 3465 | let len = offset_from(self.end, self.next_ctrl); | 
|---|
| 3466 | debug_assert_eq!(len % Group::WIDTH, 0); | 
|---|
| 3467 |  | 
|---|
| 3468 | // Split the remaining elements into two halves, but round the | 
|---|
| 3469 | // midpoint down in case there is an odd number of groups | 
|---|
| 3470 | // remaining. This ensures that: | 
|---|
| 3471 | // - The tail is at least 1 group long. | 
|---|
| 3472 | // - The split is roughly even considering we still have the | 
|---|
| 3473 | //   current group to process. | 
|---|
| 3474 | let mid = (len / 2) & !(Group::WIDTH - 1); | 
|---|
| 3475 |  | 
|---|
| 3476 | let tail = Self::new( | 
|---|
| 3477 | self.next_ctrl.add(mid), | 
|---|
| 3478 | self.data.next_n(Group::WIDTH).next_n(mid), | 
|---|
| 3479 | len - mid, | 
|---|
| 3480 | ); | 
|---|
| 3481 | debug_assert_eq!( | 
|---|
| 3482 | self.data.next_n(Group::WIDTH).next_n(mid).ptr, | 
|---|
| 3483 | tail.data.ptr | 
|---|
| 3484 | ); | 
|---|
| 3485 | debug_assert_eq!(self.end, tail.end); | 
|---|
| 3486 | self.end = self.next_ctrl.add(mid); | 
|---|
| 3487 | debug_assert_eq!(self.end.add(Group::WIDTH), tail.next_ctrl); | 
|---|
| 3488 | (self, Some(tail)) | 
|---|
| 3489 | } | 
|---|
| 3490 | } | 
|---|
| 3491 | } | 
|---|
| 3492 |  | 
|---|
| 3493 | /// # Safety | 
|---|
| 3494 | /// If `DO_CHECK_PTR_RANGE` is false, caller must ensure that we never try to iterate | 
|---|
| 3495 | /// after yielding all elements. | 
|---|
| 3496 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 3497 | unsafe fn next_impl<const DO_CHECK_PTR_RANGE: bool>(&mut self) -> Option<Bucket<T>> { | 
|---|
| 3498 | loop { | 
|---|
| 3499 | if let Some(index) = self.current_group.next() { | 
|---|
| 3500 | return Some(self.data.next_n(index)); | 
|---|
| 3501 | } | 
|---|
| 3502 |  | 
|---|
| 3503 | if DO_CHECK_PTR_RANGE && self.next_ctrl >= self.end { | 
|---|
| 3504 | return None; | 
|---|
| 3505 | } | 
|---|
| 3506 |  | 
|---|
| 3507 | // We might read past self.end up to the next group boundary, | 
|---|
| 3508 | // but this is fine because it only occurs on tables smaller | 
|---|
| 3509 | // than the group size where the trailing control bytes are all | 
|---|
| 3510 | // EMPTY. On larger tables self.end is guaranteed to be aligned | 
|---|
| 3511 | // to the group size (since tables are power-of-two sized). | 
|---|
| 3512 | self.current_group = Group::load_aligned(self.next_ctrl.cast()) | 
|---|
| 3513 | .match_full() | 
|---|
| 3514 | .into_iter(); | 
|---|
| 3515 | self.data = self.data.next_n(Group::WIDTH); | 
|---|
| 3516 | self.next_ctrl = self.next_ctrl.add(Group::WIDTH); | 
|---|
| 3517 | } | 
|---|
| 3518 | } | 
|---|
| 3519 |  | 
|---|
| 3520 | /// Folds every element into an accumulator by applying an operation, | 
|---|
| 3521 | /// returning the final result. | 
|---|
| 3522 | /// | 
|---|
| 3523 | /// `fold_impl()` takes three arguments: the number of items remaining in | 
|---|
| 3524 | /// the iterator, an initial value, and a closure with two arguments: an | 
|---|
| 3525 | /// 'accumulator', and an element. The closure returns the value that the | 
|---|
| 3526 | /// accumulator should have for the next iteration. | 
|---|
| 3527 | /// | 
|---|
| 3528 | /// The initial value is the value the accumulator will have on the first call. | 
|---|
| 3529 | /// | 
|---|
| 3530 | /// After applying this closure to every element of the iterator, `fold_impl()` | 
|---|
| 3531 | /// returns the accumulator. | 
|---|
| 3532 | /// | 
|---|
| 3533 | /// # Safety | 
|---|
| 3534 | /// | 
|---|
| 3535 | /// If any of the following conditions are violated, the result is | 
|---|
| 3536 | /// [`Undefined Behavior`]: | 
|---|
| 3537 | /// | 
|---|
| 3538 | /// * The [`RawTableInner`] / [`RawTable`] must be alive and not moved, | 
|---|
| 3539 | ///   i.e. table outlives the `RawIterRange`; | 
|---|
| 3540 | /// | 
|---|
| 3541 | /// * The provided `n` value must match the actual number of items | 
|---|
| 3542 | ///   in the table. | 
|---|
| 3543 | /// | 
|---|
| 3544 | /// [`Undefined Behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 3545 | #[ allow(clippy::while_let_on_iterator)] | 
|---|
| 3546 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 3547 | unsafe fn fold_impl<F, B>(mut self, mut n: usize, mut acc: B, mut f: F) -> B | 
|---|
| 3548 | where | 
|---|
| 3549 | F: FnMut(B, Bucket<T>) -> B, | 
|---|
| 3550 | { | 
|---|
| 3551 | loop { | 
|---|
| 3552 | while let Some(index) = self.current_group.next() { | 
|---|
| 3553 | // The returned `index` will always be in the range `0..Group::WIDTH`, | 
|---|
| 3554 | // so that calling `self.data.next_n(index)` is safe (see detailed explanation below). | 
|---|
| 3555 | debug_assert!(n != 0); | 
|---|
| 3556 | let bucket = self.data.next_n(index); | 
|---|
| 3557 | acc = f(acc, bucket); | 
|---|
| 3558 | n -= 1; | 
|---|
| 3559 | } | 
|---|
| 3560 |  | 
|---|
| 3561 | if n == 0 { | 
|---|
| 3562 | return acc; | 
|---|
| 3563 | } | 
|---|
| 3564 |  | 
|---|
| 3565 | // SAFETY: The caller of this function ensures that: | 
|---|
| 3566 | // | 
|---|
| 3567 | // 1. The provided `n` value matches the actual number of items in the table; | 
|---|
| 3568 | // 2. The table is alive and did not moved. | 
|---|
| 3569 | // | 
|---|
| 3570 | // Taking the above into account, we always stay within the bounds, because: | 
|---|
| 3571 | // | 
|---|
| 3572 | // 1. For tables smaller than the group width (self.buckets() <= Group::WIDTH), | 
|---|
| 3573 | //    we will never end up in the given branch, since we should have already | 
|---|
| 3574 | //    yielded all the elements of the table. | 
|---|
| 3575 | // | 
|---|
| 3576 | // 2. For tables larger than the group width. The number of buckets is a | 
|---|
| 3577 | //    power of two (2 ^ n), Group::WIDTH is also power of two (2 ^ k). Since | 
|---|
| 3578 | //    `(2 ^ n) > (2 ^ k)`, than `(2 ^ n) % (2 ^ k) = 0`. As we start from the | 
|---|
| 3579 | //    start of the array of control bytes, and never try to iterate after | 
|---|
| 3580 | //    getting all the elements, the last `self.current_group` will read bytes | 
|---|
| 3581 | //    from the `self.buckets() - Group::WIDTH` index.  We know also that | 
|---|
| 3582 | //    `self.current_group.next()` will always return indices within the range | 
|---|
| 3583 | //    `0..Group::WIDTH`. | 
|---|
| 3584 | // | 
|---|
| 3585 | //    Knowing all of the above and taking into account that we are synchronizing | 
|---|
| 3586 | //    the `self.data` index with the index we used to read the `self.current_group`, | 
|---|
| 3587 | //    the subsequent `self.data.next_n(index)` will always return a bucket with | 
|---|
| 3588 | //    an index number less than `self.buckets()`. | 
|---|
| 3589 | // | 
|---|
| 3590 | //    The last `self.next_ctrl`, whose index would be `self.buckets()`, will never | 
|---|
| 3591 | //    actually be read, since we should have already yielded all the elements of | 
|---|
| 3592 | //    the table. | 
|---|
| 3593 | self.current_group = Group::load_aligned(self.next_ctrl.cast()) | 
|---|
| 3594 | .match_full() | 
|---|
| 3595 | .into_iter(); | 
|---|
| 3596 | self.data = self.data.next_n(Group::WIDTH); | 
|---|
| 3597 | self.next_ctrl = self.next_ctrl.add(Group::WIDTH); | 
|---|
| 3598 | } | 
|---|
| 3599 | } | 
|---|
| 3600 | } | 
|---|
| 3601 |  | 
|---|
| 3602 | // We make raw iterators unconditionally Send and Sync, and let the PhantomData | 
|---|
| 3603 | // in the actual iterator implementations determine the real Send/Sync bounds. | 
|---|
| 3604 | unsafe impl<T> Send for RawIterRange<T> {} | 
|---|
| 3605 | unsafe impl<T> Sync for RawIterRange<T> {} | 
|---|
| 3606 |  | 
|---|
| 3607 | impl<T> Clone for RawIterRange<T> { | 
|---|
| 3608 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 3609 | fn clone(&self) -> Self { | 
|---|
| 3610 | Self { | 
|---|
| 3611 | data: self.data.clone(), | 
|---|
| 3612 | next_ctrl: self.next_ctrl, | 
|---|
| 3613 | current_group: self.current_group.clone(), | 
|---|
| 3614 | end: self.end, | 
|---|
| 3615 | } | 
|---|
| 3616 | } | 
|---|
| 3617 | } | 
|---|
| 3618 |  | 
|---|
| 3619 | impl<T> Iterator for RawIterRange<T> { | 
|---|
| 3620 | type Item = Bucket<T>; | 
|---|
| 3621 |  | 
|---|
| 3622 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 3623 | fn next(&mut self) -> Option<Bucket<T>> { | 
|---|
| 3624 | unsafe { | 
|---|
| 3625 | // SAFETY: We set checker flag to true. | 
|---|
| 3626 | self.next_impl::<true>() | 
|---|
| 3627 | } | 
|---|
| 3628 | } | 
|---|
| 3629 |  | 
|---|
| 3630 | #[ inline] | 
|---|
| 3631 | fn size_hint(&self) -> (usize, Option<usize>) { | 
|---|
| 3632 | // We don't have an item count, so just guess based on the range size. | 
|---|
| 3633 | let remaining_buckets: usize = if self.end > self.next_ctrl { | 
|---|
| 3634 | unsafe { offset_from(self.end, self.next_ctrl) } | 
|---|
| 3635 | } else { | 
|---|
| 3636 | 0 | 
|---|
| 3637 | }; | 
|---|
| 3638 |  | 
|---|
| 3639 | // Add a group width to include the group we are currently processing. | 
|---|
| 3640 | (0, Some(Group::WIDTH + remaining_buckets)) | 
|---|
| 3641 | } | 
|---|
| 3642 | } | 
|---|
| 3643 |  | 
|---|
| 3644 | impl<T> FusedIterator for RawIterRange<T> {} | 
|---|
| 3645 |  | 
|---|
| 3646 | /// Iterator which returns a raw pointer to every full bucket in the table. | 
|---|
| 3647 | /// | 
|---|
| 3648 | /// For maximum flexibility this iterator is not bound by a lifetime, but you | 
|---|
| 3649 | /// must observe several rules when using it: | 
|---|
| 3650 | /// - You must not free the hash table while iterating (including via growing/shrinking). | 
|---|
| 3651 | /// - It is fine to erase a bucket that has been yielded by the iterator. | 
|---|
| 3652 | /// - Erasing a bucket that has not yet been yielded by the iterator may still | 
|---|
| 3653 | ///   result in the iterator yielding that bucket (unless `reflect_remove` is called). | 
|---|
| 3654 | /// - It is unspecified whether an element inserted after the iterator was | 
|---|
| 3655 | ///   created will be yielded by that iterator (unless `reflect_insert` is called). | 
|---|
| 3656 | /// - The order in which the iterator yields bucket is unspecified and may | 
|---|
| 3657 | ///   change in the future. | 
|---|
| 3658 | pub struct RawIter<T> { | 
|---|
| 3659 | pub(crate) iter: RawIterRange<T>, | 
|---|
| 3660 | items: usize, | 
|---|
| 3661 | } | 
|---|
| 3662 |  | 
|---|
| 3663 | impl<T> RawIter<T> { | 
|---|
| 3664 | unsafe fn drop_elements(&mut self) { | 
|---|
| 3665 | if T::NEEDS_DROP && self.items != 0 { | 
|---|
| 3666 | for item: Bucket in self { | 
|---|
| 3667 | item.drop(); | 
|---|
| 3668 | } | 
|---|
| 3669 | } | 
|---|
| 3670 | } | 
|---|
| 3671 | } | 
|---|
| 3672 |  | 
|---|
| 3673 | impl<T> Clone for RawIter<T> { | 
|---|
| 3674 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 3675 | fn clone(&self) -> Self { | 
|---|
| 3676 | Self { | 
|---|
| 3677 | iter: self.iter.clone(), | 
|---|
| 3678 | items: self.items, | 
|---|
| 3679 | } | 
|---|
| 3680 | } | 
|---|
| 3681 | } | 
|---|
| 3682 | impl<T> Default for RawIter<T> { | 
|---|
| 3683 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 3684 | fn default() -> Self { | 
|---|
| 3685 | // SAFETY: Because the table is static, it always outlives the iter. | 
|---|
| 3686 | unsafe { RawTableInner::NEW.iter() } | 
|---|
| 3687 | } | 
|---|
| 3688 | } | 
|---|
| 3689 |  | 
|---|
| 3690 | impl<T> Iterator for RawIter<T> { | 
|---|
| 3691 | type Item = Bucket<T>; | 
|---|
| 3692 |  | 
|---|
| 3693 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 3694 | fn next(&mut self) -> Option<Bucket<T>> { | 
|---|
| 3695 | // Inner iterator iterates over buckets | 
|---|
| 3696 | // so it can do unnecessary work if we already yielded all items. | 
|---|
| 3697 | if self.items == 0 { | 
|---|
| 3698 | return None; | 
|---|
| 3699 | } | 
|---|
| 3700 |  | 
|---|
| 3701 | let nxt = unsafe { | 
|---|
| 3702 | // SAFETY: We check number of items to yield using `items` field. | 
|---|
| 3703 | self.iter.next_impl::<false>() | 
|---|
| 3704 | }; | 
|---|
| 3705 |  | 
|---|
| 3706 | debug_assert!(nxt.is_some()); | 
|---|
| 3707 | self.items -= 1; | 
|---|
| 3708 |  | 
|---|
| 3709 | nxt | 
|---|
| 3710 | } | 
|---|
| 3711 |  | 
|---|
| 3712 | #[ inline] | 
|---|
| 3713 | fn size_hint(&self) -> (usize, Option<usize>) { | 
|---|
| 3714 | (self.items, Some(self.items)) | 
|---|
| 3715 | } | 
|---|
| 3716 |  | 
|---|
| 3717 | #[ inline] | 
|---|
| 3718 | fn fold<B, F>(self, init: B, f: F) -> B | 
|---|
| 3719 | where | 
|---|
| 3720 | Self: Sized, | 
|---|
| 3721 | F: FnMut(B, Self::Item) -> B, | 
|---|
| 3722 | { | 
|---|
| 3723 | unsafe { self.iter.fold_impl(self.items, init, f) } | 
|---|
| 3724 | } | 
|---|
| 3725 | } | 
|---|
| 3726 |  | 
|---|
| 3727 | impl<T> ExactSizeIterator for RawIter<T> {} | 
|---|
| 3728 | impl<T> FusedIterator for RawIter<T> {} | 
|---|
| 3729 |  | 
|---|
| 3730 | /// Iterator which returns an index of every full bucket in the table. | 
|---|
| 3731 | /// | 
|---|
| 3732 | /// For maximum flexibility this iterator is not bound by a lifetime, but you | 
|---|
| 3733 | /// must observe several rules when using it: | 
|---|
| 3734 | /// - You must not free the hash table while iterating (including via growing/shrinking). | 
|---|
| 3735 | /// - It is fine to erase a bucket that has been yielded by the iterator. | 
|---|
| 3736 | /// - Erasing a bucket that has not yet been yielded by the iterator may still | 
|---|
| 3737 | ///   result in the iterator yielding index of that bucket. | 
|---|
| 3738 | /// - It is unspecified whether an element inserted after the iterator was | 
|---|
| 3739 | ///   created will be yielded by that iterator. | 
|---|
| 3740 | /// - The order in which the iterator yields indices of the buckets is unspecified | 
|---|
| 3741 | ///   and may change in the future. | 
|---|
| 3742 | pub(crate) struct FullBucketsIndices { | 
|---|
| 3743 | // Mask of full buckets in the current group. Bits are cleared from this | 
|---|
| 3744 | // mask as each element is processed. | 
|---|
| 3745 | current_group: BitMaskIter, | 
|---|
| 3746 |  | 
|---|
| 3747 | // Initial value of the bytes' indices of the current group (relative | 
|---|
| 3748 | // to the start of the control bytes). | 
|---|
| 3749 | group_first_index: usize, | 
|---|
| 3750 |  | 
|---|
| 3751 | // Pointer to the current group of control bytes, | 
|---|
| 3752 | // Must be aligned to the group size (Group::WIDTH). | 
|---|
| 3753 | ctrl: NonNull<u8>, | 
|---|
| 3754 |  | 
|---|
| 3755 | // Number of elements in the table. | 
|---|
| 3756 | items: usize, | 
|---|
| 3757 | } | 
|---|
| 3758 |  | 
|---|
| 3759 | impl FullBucketsIndices { | 
|---|
| 3760 | /// Advances the iterator and returns the next value. | 
|---|
| 3761 | /// | 
|---|
| 3762 | /// # Safety | 
|---|
| 3763 | /// | 
|---|
| 3764 | /// If any of the following conditions are violated, the result is | 
|---|
| 3765 | /// [`Undefined Behavior`]: | 
|---|
| 3766 | /// | 
|---|
| 3767 | /// * The [`RawTableInner`] / [`RawTable`] must be alive and not moved, | 
|---|
| 3768 | ///   i.e. table outlives the `FullBucketsIndices`; | 
|---|
| 3769 | /// | 
|---|
| 3770 | /// * It never tries to iterate after getting all elements. | 
|---|
| 3771 | /// | 
|---|
| 3772 | /// [`Undefined Behavior`]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html | 
|---|
| 3773 | #[ inline(always)] | 
|---|
| 3774 | unsafe fn next_impl(&mut self) -> Option<usize> { | 
|---|
| 3775 | loop { | 
|---|
| 3776 | if let Some(index) = self.current_group.next() { | 
|---|
| 3777 | // The returned `self.group_first_index + index` will always | 
|---|
| 3778 | // be in the range `0..self.buckets()`. See explanation below. | 
|---|
| 3779 | return Some(self.group_first_index + index); | 
|---|
| 3780 | } | 
|---|
| 3781 |  | 
|---|
| 3782 | // SAFETY: The caller of this function ensures that: | 
|---|
| 3783 | // | 
|---|
| 3784 | // 1. It never tries to iterate after getting all the elements; | 
|---|
| 3785 | // 2. The table is alive and did not moved; | 
|---|
| 3786 | // 3. The first `self.ctrl` pointed to the start of the array of control bytes. | 
|---|
| 3787 | // | 
|---|
| 3788 | // Taking the above into account, we always stay within the bounds, because: | 
|---|
| 3789 | // | 
|---|
| 3790 | // 1. For tables smaller than the group width (self.buckets() <= Group::WIDTH), | 
|---|
| 3791 | //    we will never end up in the given branch, since we should have already | 
|---|
| 3792 | //    yielded all the elements of the table. | 
|---|
| 3793 | // | 
|---|
| 3794 | // 2. For tables larger than the group width. The number of buckets is a | 
|---|
| 3795 | //    power of two (2 ^ n), Group::WIDTH is also power of two (2 ^ k). Since | 
|---|
| 3796 | //    `(2 ^ n) > (2 ^ k)`, than `(2 ^ n) % (2 ^ k) = 0`. As we start from the | 
|---|
| 3797 | //    the start of the array of control bytes, and never try to iterate after | 
|---|
| 3798 | //    getting all the elements, the last `self.ctrl` will be equal to | 
|---|
| 3799 | //    the `self.buckets() - Group::WIDTH`, so `self.current_group.next()` | 
|---|
| 3800 | //    will always contains indices within the range `0..Group::WIDTH`, | 
|---|
| 3801 | //    and subsequent `self.group_first_index + index` will always return a | 
|---|
| 3802 | //    number less than `self.buckets()`. | 
|---|
| 3803 | self.ctrl = NonNull::new_unchecked(self.ctrl.as_ptr().add(Group::WIDTH)); | 
|---|
| 3804 |  | 
|---|
| 3805 | // SAFETY: See explanation above. | 
|---|
| 3806 | self.current_group = Group::load_aligned(self.ctrl.as_ptr().cast()) | 
|---|
| 3807 | .match_full() | 
|---|
| 3808 | .into_iter(); | 
|---|
| 3809 | self.group_first_index += Group::WIDTH; | 
|---|
| 3810 | } | 
|---|
| 3811 | } | 
|---|
| 3812 | } | 
|---|
| 3813 |  | 
|---|
| 3814 | impl Iterator for FullBucketsIndices { | 
|---|
| 3815 | type Item = usize; | 
|---|
| 3816 |  | 
|---|
| 3817 | /// Advances the iterator and returns the next value. It is up to | 
|---|
| 3818 | /// the caller to ensure that the `RawTable` outlives the `FullBucketsIndices`, | 
|---|
| 3819 | /// because we cannot make the `next` method unsafe. | 
|---|
| 3820 | #[ inline(always)] | 
|---|
| 3821 | fn next(&mut self) -> Option<usize> { | 
|---|
| 3822 | // Return if we already yielded all items. | 
|---|
| 3823 | if self.items == 0 { | 
|---|
| 3824 | return None; | 
|---|
| 3825 | } | 
|---|
| 3826 |  | 
|---|
| 3827 | let nxt = unsafe { | 
|---|
| 3828 | // SAFETY: | 
|---|
| 3829 | // 1. We check number of items to yield using `items` field. | 
|---|
| 3830 | // 2. The caller ensures that the table is alive and has not moved. | 
|---|
| 3831 | self.next_impl() | 
|---|
| 3832 | }; | 
|---|
| 3833 |  | 
|---|
| 3834 | debug_assert!(nxt.is_some()); | 
|---|
| 3835 | self.items -= 1; | 
|---|
| 3836 |  | 
|---|
| 3837 | nxt | 
|---|
| 3838 | } | 
|---|
| 3839 |  | 
|---|
| 3840 | #[ inline(always)] | 
|---|
| 3841 | fn size_hint(&self) -> (usize, Option<usize>) { | 
|---|
| 3842 | (self.items, Some(self.items)) | 
|---|
| 3843 | } | 
|---|
| 3844 | } | 
|---|
| 3845 |  | 
|---|
| 3846 | impl ExactSizeIterator for FullBucketsIndices {} | 
|---|
| 3847 | impl FusedIterator for FullBucketsIndices {} | 
|---|
| 3848 |  | 
|---|
| 3849 | /// Iterator which consumes a table and returns elements. | 
|---|
| 3850 | pub struct RawIntoIter<T, A: Allocator = Global> { | 
|---|
| 3851 | iter: RawIter<T>, | 
|---|
| 3852 | allocation: Option<(NonNull<u8>, Layout, A)>, | 
|---|
| 3853 | marker: PhantomData<T>, | 
|---|
| 3854 | } | 
|---|
| 3855 |  | 
|---|
| 3856 | impl<T, A: Allocator> RawIntoIter<T, A> { | 
|---|
| 3857 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 3858 | pub fn iter(&self) -> RawIter<T> { | 
|---|
| 3859 | self.iter.clone() | 
|---|
| 3860 | } | 
|---|
| 3861 | } | 
|---|
| 3862 |  | 
|---|
| 3863 | unsafe impl<T, A: Allocator> Send for RawIntoIter<T, A> | 
|---|
| 3864 | where | 
|---|
| 3865 | T: Send, | 
|---|
| 3866 | A: Send, | 
|---|
| 3867 | { | 
|---|
| 3868 | } | 
|---|
| 3869 | unsafe impl<T, A: Allocator> Sync for RawIntoIter<T, A> | 
|---|
| 3870 | where | 
|---|
| 3871 | T: Sync, | 
|---|
| 3872 | A: Sync, | 
|---|
| 3873 | { | 
|---|
| 3874 | } | 
|---|
| 3875 |  | 
|---|
| 3876 | #[ cfg(feature = "nightly")] | 
|---|
| 3877 | unsafe impl<#[ may_dangle] T, A: Allocator> Drop for RawIntoIter<T, A> { | 
|---|
| 3878 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 3879 | fn drop(&mut self) { | 
|---|
| 3880 | unsafe { | 
|---|
| 3881 | // Drop all remaining elements | 
|---|
| 3882 | self.iter.drop_elements(); | 
|---|
| 3883 |  | 
|---|
| 3884 | // Free the table | 
|---|
| 3885 | if let Some((ptr: NonNull, layout: Layout, ref alloc: &A)) = self.allocation { | 
|---|
| 3886 | alloc.deallocate(ptr, layout); | 
|---|
| 3887 | } | 
|---|
| 3888 | } | 
|---|
| 3889 | } | 
|---|
| 3890 | } | 
|---|
| 3891 | #[ cfg(not(feature = "nightly"))] | 
|---|
| 3892 | impl<T, A: Allocator> Drop for RawIntoIter<T, A> { | 
|---|
| 3893 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 3894 | fn drop(&mut self) { | 
|---|
| 3895 | unsafe { | 
|---|
| 3896 | // Drop all remaining elements | 
|---|
| 3897 | self.iter.drop_elements(); | 
|---|
| 3898 |  | 
|---|
| 3899 | // Free the table | 
|---|
| 3900 | if let Some((ptr, layout, ref alloc)) = self.allocation { | 
|---|
| 3901 | alloc.deallocate(ptr, layout); | 
|---|
| 3902 | } | 
|---|
| 3903 | } | 
|---|
| 3904 | } | 
|---|
| 3905 | } | 
|---|
| 3906 |  | 
|---|
| 3907 | impl<T, A: Allocator> Default for RawIntoIter<T, A> { | 
|---|
| 3908 | fn default() -> Self { | 
|---|
| 3909 | Self { | 
|---|
| 3910 | iter: Default::default(), | 
|---|
| 3911 | allocation: None, | 
|---|
| 3912 | marker: PhantomData, | 
|---|
| 3913 | } | 
|---|
| 3914 | } | 
|---|
| 3915 | } | 
|---|
| 3916 | impl<T, A: Allocator> Iterator for RawIntoIter<T, A> { | 
|---|
| 3917 | type Item = T; | 
|---|
| 3918 |  | 
|---|
| 3919 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 3920 | fn next(&mut self) -> Option<T> { | 
|---|
| 3921 | unsafe { Some(self.iter.next()?.read()) } | 
|---|
| 3922 | } | 
|---|
| 3923 |  | 
|---|
| 3924 | #[ inline] | 
|---|
| 3925 | fn size_hint(&self) -> (usize, Option<usize>) { | 
|---|
| 3926 | self.iter.size_hint() | 
|---|
| 3927 | } | 
|---|
| 3928 | } | 
|---|
| 3929 |  | 
|---|
| 3930 | impl<T, A: Allocator> ExactSizeIterator for RawIntoIter<T, A> {} | 
|---|
| 3931 | impl<T, A: Allocator> FusedIterator for RawIntoIter<T, A> {} | 
|---|
| 3932 |  | 
|---|
| 3933 | /// Iterator which consumes elements without freeing the table storage. | 
|---|
| 3934 | pub struct RawDrain<'a, T, A: Allocator = Global> { | 
|---|
| 3935 | iter: RawIter<T>, | 
|---|
| 3936 |  | 
|---|
| 3937 | // The table is moved into the iterator for the duration of the drain. This | 
|---|
| 3938 | // ensures that an empty table is left if the drain iterator is leaked | 
|---|
| 3939 | // without dropping. | 
|---|
| 3940 | table: RawTableInner, | 
|---|
| 3941 | orig_table: NonNull<RawTableInner>, | 
|---|
| 3942 |  | 
|---|
| 3943 | // We don't use a &'a mut RawTable<T> because we want RawDrain to be | 
|---|
| 3944 | // covariant over T. | 
|---|
| 3945 | marker: PhantomData<&'a RawTable<T, A>>, | 
|---|
| 3946 | } | 
|---|
| 3947 |  | 
|---|
| 3948 | impl<T, A: Allocator> RawDrain<'_, T, A> { | 
|---|
| 3949 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 3950 | pub fn iter(&self) -> RawIter<T> { | 
|---|
| 3951 | self.iter.clone() | 
|---|
| 3952 | } | 
|---|
| 3953 | } | 
|---|
| 3954 |  | 
|---|
| 3955 | unsafe impl<T, A: Allocator> Send for RawDrain<'_, T, A> | 
|---|
| 3956 | where | 
|---|
| 3957 | T: Send, | 
|---|
| 3958 | A: Send, | 
|---|
| 3959 | { | 
|---|
| 3960 | } | 
|---|
| 3961 | unsafe impl<T, A: Allocator> Sync for RawDrain<'_, T, A> | 
|---|
| 3962 | where | 
|---|
| 3963 | T: Sync, | 
|---|
| 3964 | A: Sync, | 
|---|
| 3965 | { | 
|---|
| 3966 | } | 
|---|
| 3967 |  | 
|---|
| 3968 | impl<T, A: Allocator> Drop for RawDrain<'_, T, A> { | 
|---|
| 3969 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 3970 | fn drop(&mut self) { | 
|---|
| 3971 | unsafe { | 
|---|
| 3972 | // Drop all remaining elements. Note that this may panic. | 
|---|
| 3973 | self.iter.drop_elements(); | 
|---|
| 3974 |  | 
|---|
| 3975 | // Reset the contents of the table now that all elements have been | 
|---|
| 3976 | // dropped. | 
|---|
| 3977 | self.table.clear_no_drop(); | 
|---|
| 3978 |  | 
|---|
| 3979 | // Move the now empty table back to its original location. | 
|---|
| 3980 | self.orig_table | 
|---|
| 3981 | .as_ptr() | 
|---|
| 3982 | .copy_from_nonoverlapping(&self.table, count:1); | 
|---|
| 3983 | } | 
|---|
| 3984 | } | 
|---|
| 3985 | } | 
|---|
| 3986 |  | 
|---|
| 3987 | impl<T, A: Allocator> Iterator for RawDrain<'_, T, A> { | 
|---|
| 3988 | type Item = T; | 
|---|
| 3989 |  | 
|---|
| 3990 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 3991 | fn next(&mut self) -> Option<T> { | 
|---|
| 3992 | unsafe { | 
|---|
| 3993 | let item: Bucket = self.iter.next()?; | 
|---|
| 3994 | Some(item.read()) | 
|---|
| 3995 | } | 
|---|
| 3996 | } | 
|---|
| 3997 |  | 
|---|
| 3998 | #[ inline] | 
|---|
| 3999 | fn size_hint(&self) -> (usize, Option<usize>) { | 
|---|
| 4000 | self.iter.size_hint() | 
|---|
| 4001 | } | 
|---|
| 4002 | } | 
|---|
| 4003 |  | 
|---|
| 4004 | impl<T, A: Allocator> ExactSizeIterator for RawDrain<'_, T, A> {} | 
|---|
| 4005 | impl<T, A: Allocator> FusedIterator for RawDrain<'_, T, A> {} | 
|---|
| 4006 |  | 
|---|
| 4007 | /// Iterator over occupied buckets that could match a given hash. | 
|---|
| 4008 | /// | 
|---|
| 4009 | /// `RawTable` only stores 7 bits of the hash value, so this iterator may return | 
|---|
| 4010 | /// items that have a hash value different than the one provided. You should | 
|---|
| 4011 | /// always validate the returned values before using them. | 
|---|
| 4012 | /// | 
|---|
| 4013 | /// For maximum flexibility this iterator is not bound by a lifetime, but you | 
|---|
| 4014 | /// must observe several rules when using it: | 
|---|
| 4015 | /// - You must not free the hash table while iterating (including via growing/shrinking). | 
|---|
| 4016 | /// - It is fine to erase a bucket that has been yielded by the iterator. | 
|---|
| 4017 | /// - Erasing a bucket that has not yet been yielded by the iterator may still | 
|---|
| 4018 | ///   result in the iterator yielding that bucket. | 
|---|
| 4019 | /// - It is unspecified whether an element inserted after the iterator was | 
|---|
| 4020 | ///   created will be yielded by that iterator. | 
|---|
| 4021 | /// - The order in which the iterator yields buckets is unspecified and may | 
|---|
| 4022 | ///   change in the future. | 
|---|
| 4023 | pub struct RawIterHash<T> { | 
|---|
| 4024 | inner: RawIterHashInner, | 
|---|
| 4025 | _marker: PhantomData<T>, | 
|---|
| 4026 | } | 
|---|
| 4027 |  | 
|---|
| 4028 | #[ derive(Clone)] | 
|---|
| 4029 | struct RawIterHashInner { | 
|---|
| 4030 | // See `RawTableInner`'s corresponding fields for details. | 
|---|
| 4031 | // We can't store a `*const RawTableInner` as it would get | 
|---|
| 4032 | // invalidated by the user calling `&mut` methods on `RawTable`. | 
|---|
| 4033 | bucket_mask: usize, | 
|---|
| 4034 | ctrl: NonNull<u8>, | 
|---|
| 4035 |  | 
|---|
| 4036 | // The top 7 bits of the hash. | 
|---|
| 4037 | tag_hash: Tag, | 
|---|
| 4038 |  | 
|---|
| 4039 | // The sequence of groups to probe in the search. | 
|---|
| 4040 | probe_seq: ProbeSeq, | 
|---|
| 4041 |  | 
|---|
| 4042 | group: Group, | 
|---|
| 4043 |  | 
|---|
| 4044 | // The elements within the group with a matching tag-hash. | 
|---|
| 4045 | bitmask: BitMaskIter, | 
|---|
| 4046 | } | 
|---|
| 4047 |  | 
|---|
| 4048 | impl<T> RawIterHash<T> { | 
|---|
| 4049 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 4050 | unsafe fn new<A: Allocator>(table: &RawTable<T, A>, hash: u64) -> Self { | 
|---|
| 4051 | RawIterHash { | 
|---|
| 4052 | inner: RawIterHashInner::new(&table.table, hash), | 
|---|
| 4053 | _marker: PhantomData, | 
|---|
| 4054 | } | 
|---|
| 4055 | } | 
|---|
| 4056 | } | 
|---|
| 4057 |  | 
|---|
| 4058 | impl<T> Clone for RawIterHash<T> { | 
|---|
| 4059 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 4060 | fn clone(&self) -> Self { | 
|---|
| 4061 | Self { | 
|---|
| 4062 | inner: self.inner.clone(), | 
|---|
| 4063 | _marker: PhantomData, | 
|---|
| 4064 | } | 
|---|
| 4065 | } | 
|---|
| 4066 | } | 
|---|
| 4067 |  | 
|---|
| 4068 | impl<T> Default for RawIterHash<T> { | 
|---|
| 4069 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 4070 | fn default() -> Self { | 
|---|
| 4071 | Self { | 
|---|
| 4072 | // SAFETY: Because the table is static, it always outlives the iter. | 
|---|
| 4073 | inner: unsafe { RawIterHashInner::new(&RawTableInner::NEW, hash:0) }, | 
|---|
| 4074 | _marker: PhantomData, | 
|---|
| 4075 | } | 
|---|
| 4076 | } | 
|---|
| 4077 | } | 
|---|
| 4078 |  | 
|---|
| 4079 | impl RawIterHashInner { | 
|---|
| 4080 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 4081 | unsafe fn new(table: &RawTableInner, hash: u64) -> Self { | 
|---|
| 4082 | let tag_hash: Tag = Tag::full(hash); | 
|---|
| 4083 | let probe_seq: ProbeSeq = table.probe_seq(hash); | 
|---|
| 4084 | let group: Group = Group::load(ptr:table.ctrl(index:probe_seq.pos)); | 
|---|
| 4085 | let bitmask: BitMaskIter = group.match_tag(tag_hash).into_iter(); | 
|---|
| 4086 |  | 
|---|
| 4087 | RawIterHashInner { | 
|---|
| 4088 | bucket_mask: table.bucket_mask, | 
|---|
| 4089 | ctrl: table.ctrl, | 
|---|
| 4090 | tag_hash, | 
|---|
| 4091 | probe_seq, | 
|---|
| 4092 | group, | 
|---|
| 4093 | bitmask, | 
|---|
| 4094 | } | 
|---|
| 4095 | } | 
|---|
| 4096 | } | 
|---|
| 4097 |  | 
|---|
| 4098 | impl<T> Iterator for RawIterHash<T> { | 
|---|
| 4099 | type Item = Bucket<T>; | 
|---|
| 4100 |  | 
|---|
| 4101 | fn next(&mut self) -> Option<Bucket<T>> { | 
|---|
| 4102 | unsafe { | 
|---|
| 4103 | match self.inner.next() { | 
|---|
| 4104 | Some(index: usize) => { | 
|---|
| 4105 | // Can't use `RawTable::bucket` here as we don't have | 
|---|
| 4106 | // an actual `RawTable` reference to use. | 
|---|
| 4107 | debug_assert!(index <= self.inner.bucket_mask); | 
|---|
| 4108 | let bucket: Bucket = Bucket::from_base_index(self.inner.ctrl.cast(), index); | 
|---|
| 4109 | Some(bucket) | 
|---|
| 4110 | } | 
|---|
| 4111 | None => None, | 
|---|
| 4112 | } | 
|---|
| 4113 | } | 
|---|
| 4114 | } | 
|---|
| 4115 | } | 
|---|
| 4116 |  | 
|---|
| 4117 | impl Iterator for RawIterHashInner { | 
|---|
| 4118 | type Item = usize; | 
|---|
| 4119 |  | 
|---|
| 4120 | fn next(&mut self) -> Option<Self::Item> { | 
|---|
| 4121 | unsafe { | 
|---|
| 4122 | loop { | 
|---|
| 4123 | if let Some(bit) = self.bitmask.next() { | 
|---|
| 4124 | let index = (self.probe_seq.pos + bit) & self.bucket_mask; | 
|---|
| 4125 | return Some(index); | 
|---|
| 4126 | } | 
|---|
| 4127 | if likely(self.group.match_empty().any_bit_set()) { | 
|---|
| 4128 | return None; | 
|---|
| 4129 | } | 
|---|
| 4130 | self.probe_seq.move_next(self.bucket_mask); | 
|---|
| 4131 |  | 
|---|
| 4132 | // Can't use `RawTableInner::ctrl` here as we don't have | 
|---|
| 4133 | // an actual `RawTableInner` reference to use. | 
|---|
| 4134 | let index = self.probe_seq.pos; | 
|---|
| 4135 | debug_assert!(index < self.bucket_mask + 1 + Group::WIDTH); | 
|---|
| 4136 | let group_ctrl = self.ctrl.as_ptr().add(index).cast(); | 
|---|
| 4137 |  | 
|---|
| 4138 | self.group = Group::load(group_ctrl); | 
|---|
| 4139 | self.bitmask = self.group.match_tag(self.tag_hash).into_iter(); | 
|---|
| 4140 | } | 
|---|
| 4141 | } | 
|---|
| 4142 | } | 
|---|
| 4143 | } | 
|---|
| 4144 |  | 
|---|
| 4145 | pub(crate) struct RawExtractIf<'a, T, A: Allocator> { | 
|---|
| 4146 | pub iter: RawIter<T>, | 
|---|
| 4147 | pub table: &'a mut RawTable<T, A>, | 
|---|
| 4148 | } | 
|---|
| 4149 |  | 
|---|
| 4150 | impl<T, A: Allocator> RawExtractIf<'_, T, A> { | 
|---|
| 4151 | #[ cfg_attr(feature = "inline-more", inline)] | 
|---|
| 4152 | pub(crate) fn next<F>(&mut self, mut f: F) -> Option<T> | 
|---|
| 4153 | where | 
|---|
| 4154 | F: FnMut(&mut T) -> bool, | 
|---|
| 4155 | { | 
|---|
| 4156 | unsafe { | 
|---|
| 4157 | for item: Bucket in &mut self.iter { | 
|---|
| 4158 | if f(item.as_mut()) { | 
|---|
| 4159 | return Some(self.table.remove(item).0); | 
|---|
| 4160 | } | 
|---|
| 4161 | } | 
|---|
| 4162 | } | 
|---|
| 4163 | None | 
|---|
| 4164 | } | 
|---|
| 4165 | } | 
|---|
| 4166 |  | 
|---|
| 4167 | #[ cfg(test)] | 
|---|
| 4168 | mod test_map { | 
|---|
| 4169 | use super::*; | 
|---|
| 4170 |  | 
|---|
| 4171 | #[ test] | 
|---|
| 4172 | fn test_minimum_capacity_for_small_types() { | 
|---|
| 4173 | #[ track_caller] | 
|---|
| 4174 | fn test_t<T>() { | 
|---|
| 4175 | let raw_table: RawTable<T> = RawTable::with_capacity(1); | 
|---|
| 4176 | let actual_buckets = raw_table.buckets(); | 
|---|
| 4177 | let min_buckets = Group::WIDTH / core::mem::size_of::<T>(); | 
|---|
| 4178 | assert!( | 
|---|
| 4179 | actual_buckets >= min_buckets, | 
|---|
| 4180 | "expected at least {min_buckets} buckets, got {actual_buckets} buckets" | 
|---|
| 4181 | ); | 
|---|
| 4182 | } | 
|---|
| 4183 |  | 
|---|
| 4184 | test_t::<u8>(); | 
|---|
| 4185 |  | 
|---|
| 4186 | // This is only "small" for some platforms, like x86_64 with SSE2, but | 
|---|
| 4187 | // there's no harm in running it on other platforms. | 
|---|
| 4188 | test_t::<u16>(); | 
|---|
| 4189 | } | 
|---|
| 4190 |  | 
|---|
| 4191 | fn rehash_in_place<T>(table: &mut RawTable<T>, hasher: impl Fn(&T) -> u64) { | 
|---|
| 4192 | unsafe { | 
|---|
| 4193 | table.table.rehash_in_place( | 
|---|
| 4194 | &|table, index| hasher(table.bucket::<T>(index).as_ref()), | 
|---|
| 4195 | mem::size_of::<T>(), | 
|---|
| 4196 | if mem::needs_drop::<T>() { | 
|---|
| 4197 | Some(|ptr| ptr::drop_in_place(ptr as *mut T)) | 
|---|
| 4198 | } else { | 
|---|
| 4199 | None | 
|---|
| 4200 | }, | 
|---|
| 4201 | ); | 
|---|
| 4202 | } | 
|---|
| 4203 | } | 
|---|
| 4204 |  | 
|---|
| 4205 | #[ test] | 
|---|
| 4206 | fn rehash() { | 
|---|
| 4207 | let mut table = RawTable::new(); | 
|---|
| 4208 | let hasher = |i: &u64| *i; | 
|---|
| 4209 | for i in 0..100 { | 
|---|
| 4210 | table.insert(i, i, hasher); | 
|---|
| 4211 | } | 
|---|
| 4212 |  | 
|---|
| 4213 | for i in 0..100 { | 
|---|
| 4214 | unsafe { | 
|---|
| 4215 | assert_eq!(table.find(i, |x| *x == i).map(|b| b.read()), Some(i)); | 
|---|
| 4216 | } | 
|---|
| 4217 | assert!(table.find(i + 100, |x| *x == i + 100).is_none()); | 
|---|
| 4218 | } | 
|---|
| 4219 |  | 
|---|
| 4220 | rehash_in_place(&mut table, hasher); | 
|---|
| 4221 |  | 
|---|
| 4222 | for i in 0..100 { | 
|---|
| 4223 | unsafe { | 
|---|
| 4224 | assert_eq!(table.find(i, |x| *x == i).map(|b| b.read()), Some(i)); | 
|---|
| 4225 | } | 
|---|
| 4226 | assert!(table.find(i + 100, |x| *x == i + 100).is_none()); | 
|---|
| 4227 | } | 
|---|
| 4228 | } | 
|---|
| 4229 |  | 
|---|
| 4230 | /// CHECKING THAT WE ARE NOT TRYING TO READ THE MEMORY OF | 
|---|
| 4231 | /// AN UNINITIALIZED TABLE DURING THE DROP | 
|---|
| 4232 | #[ test] | 
|---|
| 4233 | fn test_drop_uninitialized() { | 
|---|
| 4234 | use ::alloc::vec::Vec; | 
|---|
| 4235 |  | 
|---|
| 4236 | let table = unsafe { | 
|---|
| 4237 | // SAFETY: The `buckets` is power of two and we're not | 
|---|
| 4238 | // trying to actually use the returned RawTable. | 
|---|
| 4239 | RawTable::<(u64, Vec<i32>)>::new_uninitialized(Global, 8, Fallibility::Infallible) | 
|---|
| 4240 | .unwrap() | 
|---|
| 4241 | }; | 
|---|
| 4242 | drop(table); | 
|---|
| 4243 | } | 
|---|
| 4244 |  | 
|---|
| 4245 | /// CHECKING THAT WE DON'T TRY TO DROP DATA IF THE `ITEMS` | 
|---|
| 4246 | /// ARE ZERO, EVEN IF WE HAVE `FULL` CONTROL BYTES. | 
|---|
| 4247 | #[ test] | 
|---|
| 4248 | fn test_drop_zero_items() { | 
|---|
| 4249 | use ::alloc::vec::Vec; | 
|---|
| 4250 | unsafe { | 
|---|
| 4251 | // SAFETY: The `buckets` is power of two and we're not | 
|---|
| 4252 | // trying to actually use the returned RawTable. | 
|---|
| 4253 | let mut table = | 
|---|
| 4254 | RawTable::<(u64, Vec<i32>)>::new_uninitialized(Global, 8, Fallibility::Infallible) | 
|---|
| 4255 | .unwrap(); | 
|---|
| 4256 |  | 
|---|
| 4257 | // WE SIMULATE, AS IT WERE, A FULL TABLE. | 
|---|
| 4258 |  | 
|---|
| 4259 | // SAFETY: We checked that the table is allocated and therefore the table already has | 
|---|
| 4260 | // `self.bucket_mask + 1 + Group::WIDTH` number of control bytes (see TableLayout::calculate_layout_for) | 
|---|
| 4261 | // so writing `table.table.num_ctrl_bytes() == bucket_mask + 1 + Group::WIDTH` bytes is safe. | 
|---|
| 4262 | table.table.ctrl_slice().fill_empty(); | 
|---|
| 4263 |  | 
|---|
| 4264 | // SAFETY: table.capacity() is guaranteed to be smaller than table.buckets() | 
|---|
| 4265 | table.table.ctrl(0).write_bytes(0, table.capacity()); | 
|---|
| 4266 |  | 
|---|
| 4267 | // Fix up the trailing control bytes. See the comments in set_ctrl | 
|---|
| 4268 | // for the handling of tables smaller than the group width. | 
|---|
| 4269 | if table.buckets() < Group::WIDTH { | 
|---|
| 4270 | // SAFETY: We have `self.bucket_mask + 1 + Group::WIDTH` number of control bytes, | 
|---|
| 4271 | // so copying `self.buckets() == self.bucket_mask + 1` bytes with offset equal to | 
|---|
| 4272 | // `Group::WIDTH` is safe | 
|---|
| 4273 | table | 
|---|
| 4274 | .table | 
|---|
| 4275 | .ctrl(0) | 
|---|
| 4276 | .copy_to(table.table.ctrl(Group::WIDTH), table.table.buckets()); | 
|---|
| 4277 | } else { | 
|---|
| 4278 | // SAFETY: We have `self.bucket_mask + 1 + Group::WIDTH` number of | 
|---|
| 4279 | // control bytes,so copying `Group::WIDTH` bytes with offset equal | 
|---|
| 4280 | // to `self.buckets() == self.bucket_mask + 1` is safe | 
|---|
| 4281 | table | 
|---|
| 4282 | .table | 
|---|
| 4283 | .ctrl(0) | 
|---|
| 4284 | .copy_to(table.table.ctrl(table.table.buckets()), Group::WIDTH); | 
|---|
| 4285 | } | 
|---|
| 4286 | drop(table); | 
|---|
| 4287 | } | 
|---|
| 4288 | } | 
|---|
| 4289 |  | 
|---|
| 4290 | /// CHECKING THAT WE DON'T TRY TO DROP DATA IF THE `ITEMS` | 
|---|
| 4291 | /// ARE ZERO, EVEN IF WE HAVE `FULL` CONTROL BYTES. | 
|---|
| 4292 | #[ test] | 
|---|
| 4293 | fn test_catch_panic_clone_from() { | 
|---|
| 4294 | use super::{AllocError, Allocator, Global}; | 
|---|
| 4295 | use ::alloc::sync::Arc; | 
|---|
| 4296 | use ::alloc::vec::Vec; | 
|---|
| 4297 | use core::sync::atomic::{AtomicI8, Ordering}; | 
|---|
| 4298 | use std::thread; | 
|---|
| 4299 |  | 
|---|
| 4300 | struct MyAllocInner { | 
|---|
| 4301 | drop_count: Arc<AtomicI8>, | 
|---|
| 4302 | } | 
|---|
| 4303 |  | 
|---|
| 4304 | #[ derive(Clone)] | 
|---|
| 4305 | struct MyAlloc { | 
|---|
| 4306 | _inner: Arc<MyAllocInner>, | 
|---|
| 4307 | } | 
|---|
| 4308 |  | 
|---|
| 4309 | impl Drop for MyAllocInner { | 
|---|
| 4310 | fn drop(&mut self) { | 
|---|
| 4311 | println!( "MyAlloc freed."); | 
|---|
| 4312 | self.drop_count.fetch_sub(1, Ordering::SeqCst); | 
|---|
| 4313 | } | 
|---|
| 4314 | } | 
|---|
| 4315 |  | 
|---|
| 4316 | unsafe impl Allocator for MyAlloc { | 
|---|
| 4317 | fn allocate(&self, layout: Layout) -> std::result::Result<NonNull<[u8]>, AllocError> { | 
|---|
| 4318 | let g = Global; | 
|---|
| 4319 | g.allocate(layout) | 
|---|
| 4320 | } | 
|---|
| 4321 |  | 
|---|
| 4322 | unsafe fn deallocate(&self, ptr: NonNull<u8>, layout: Layout) { | 
|---|
| 4323 | let g = Global; | 
|---|
| 4324 | g.deallocate(ptr, layout) | 
|---|
| 4325 | } | 
|---|
| 4326 | } | 
|---|
| 4327 |  | 
|---|
| 4328 | const DISARMED: bool = false; | 
|---|
| 4329 | const ARMED: bool = true; | 
|---|
| 4330 |  | 
|---|
| 4331 | struct CheckedCloneDrop { | 
|---|
| 4332 | panic_in_clone: bool, | 
|---|
| 4333 | dropped: bool, | 
|---|
| 4334 | need_drop: Vec<u64>, | 
|---|
| 4335 | } | 
|---|
| 4336 |  | 
|---|
| 4337 | impl Clone for CheckedCloneDrop { | 
|---|
| 4338 | fn clone(&self) -> Self { | 
|---|
| 4339 | if self.panic_in_clone { | 
|---|
| 4340 | panic!( "panic in clone") | 
|---|
| 4341 | } | 
|---|
| 4342 | Self { | 
|---|
| 4343 | panic_in_clone: self.panic_in_clone, | 
|---|
| 4344 | dropped: self.dropped, | 
|---|
| 4345 | need_drop: self.need_drop.clone(), | 
|---|
| 4346 | } | 
|---|
| 4347 | } | 
|---|
| 4348 | } | 
|---|
| 4349 |  | 
|---|
| 4350 | impl Drop for CheckedCloneDrop { | 
|---|
| 4351 | fn drop(&mut self) { | 
|---|
| 4352 | if self.dropped { | 
|---|
| 4353 | panic!( "double drop"); | 
|---|
| 4354 | } | 
|---|
| 4355 | self.dropped = true; | 
|---|
| 4356 | } | 
|---|
| 4357 | } | 
|---|
| 4358 |  | 
|---|
| 4359 | let dropped: Arc<AtomicI8> = Arc::new(AtomicI8::new(2)); | 
|---|
| 4360 |  | 
|---|
| 4361 | let mut table = RawTable::new_in(MyAlloc { | 
|---|
| 4362 | _inner: Arc::new(MyAllocInner { | 
|---|
| 4363 | drop_count: dropped.clone(), | 
|---|
| 4364 | }), | 
|---|
| 4365 | }); | 
|---|
| 4366 |  | 
|---|
| 4367 | for (idx, panic_in_clone) in core::iter::repeat(DISARMED).take(7).enumerate() { | 
|---|
| 4368 | let idx = idx as u64; | 
|---|
| 4369 | table.insert( | 
|---|
| 4370 | idx, | 
|---|
| 4371 | ( | 
|---|
| 4372 | idx, | 
|---|
| 4373 | CheckedCloneDrop { | 
|---|
| 4374 | panic_in_clone, | 
|---|
| 4375 | dropped: false, | 
|---|
| 4376 | need_drop: vec![idx], | 
|---|
| 4377 | }, | 
|---|
| 4378 | ), | 
|---|
| 4379 | |(k, _)| *k, | 
|---|
| 4380 | ); | 
|---|
| 4381 | } | 
|---|
| 4382 |  | 
|---|
| 4383 | assert_eq!(table.len(), 7); | 
|---|
| 4384 |  | 
|---|
| 4385 | thread::scope(|s| { | 
|---|
| 4386 | let result = s.spawn(|| { | 
|---|
| 4387 | let armed_flags = [ | 
|---|
| 4388 | DISARMED, DISARMED, ARMED, DISARMED, DISARMED, DISARMED, DISARMED, | 
|---|
| 4389 | ]; | 
|---|
| 4390 | let mut scope_table = RawTable::new_in(MyAlloc { | 
|---|
| 4391 | _inner: Arc::new(MyAllocInner { | 
|---|
| 4392 | drop_count: dropped.clone(), | 
|---|
| 4393 | }), | 
|---|
| 4394 | }); | 
|---|
| 4395 | for (idx, &panic_in_clone) in armed_flags.iter().enumerate() { | 
|---|
| 4396 | let idx = idx as u64; | 
|---|
| 4397 | scope_table.insert( | 
|---|
| 4398 | idx, | 
|---|
| 4399 | ( | 
|---|
| 4400 | idx, | 
|---|
| 4401 | CheckedCloneDrop { | 
|---|
| 4402 | panic_in_clone, | 
|---|
| 4403 | dropped: false, | 
|---|
| 4404 | need_drop: vec![idx + 100], | 
|---|
| 4405 | }, | 
|---|
| 4406 | ), | 
|---|
| 4407 | |(k, _)| *k, | 
|---|
| 4408 | ); | 
|---|
| 4409 | } | 
|---|
| 4410 | table.clone_from(&scope_table); | 
|---|
| 4411 | }); | 
|---|
| 4412 | assert!(result.join().is_err()); | 
|---|
| 4413 | }); | 
|---|
| 4414 |  | 
|---|
| 4415 | // Let's check that all iterators work fine and do not return elements | 
|---|
| 4416 | // (especially `RawIterRange`, which does not depend on the number of | 
|---|
| 4417 | // elements in the table, but looks directly at the control bytes) | 
|---|
| 4418 | // | 
|---|
| 4419 | // SAFETY: We know for sure that `RawTable` will outlive | 
|---|
| 4420 | // the returned `RawIter / RawIterRange` iterator. | 
|---|
| 4421 | assert_eq!(table.len(), 0); | 
|---|
| 4422 | assert_eq!(unsafe { table.iter().count() }, 0); | 
|---|
| 4423 | assert_eq!(unsafe { table.iter().iter.count() }, 0); | 
|---|
| 4424 |  | 
|---|
| 4425 | for idx in 0..table.buckets() { | 
|---|
| 4426 | let idx = idx as u64; | 
|---|
| 4427 | assert!( | 
|---|
| 4428 | table.find(idx, |(k, _)| *k == idx).is_none(), | 
|---|
| 4429 | "Index: {idx}" | 
|---|
| 4430 | ); | 
|---|
| 4431 | } | 
|---|
| 4432 |  | 
|---|
| 4433 | // All allocator clones should already be dropped. | 
|---|
| 4434 | assert_eq!(dropped.load(Ordering::SeqCst), 1); | 
|---|
| 4435 | } | 
|---|
| 4436 | } | 
|---|
| 4437 |  | 
|---|