1use memchr::{memchr, memchr2, memchr3, memrchr, memrchr2, memrchr3};
2
3mod scalar;
4
5#[inline]
6fn build_table(byteset: &[u8]) -> [u8; 256] {
7 let mut table: [u8; 256] = [0u8; 256];
8 for &b: u8 in byteset {
9 table[b as usize] = 1;
10 }
11 table
12}
13
14#[inline]
15pub(crate) fn find(haystack: &[u8], byteset: &[u8]) -> Option<usize> {
16 match byteset.len() {
17 0 => None,
18 1 => memchr(needle:byteset[0], haystack),
19 2 => memchr2(needle1:byteset[0], needle2:byteset[1], haystack),
20 3 => memchr3(needle1:byteset[0], needle2:byteset[1], needle3:byteset[2], haystack),
21 _ => {
22 let table: [u8; 256] = build_table(byteset);
23 scalar::forward_search_bytes(s:haystack, |b: u8| table[b as usize] != 0)
24 }
25 }
26}
27
28#[inline]
29pub(crate) fn rfind(haystack: &[u8], byteset: &[u8]) -> Option<usize> {
30 match byteset.len() {
31 0 => None,
32 1 => memrchr(needle:byteset[0], haystack),
33 2 => memrchr2(needle1:byteset[0], needle2:byteset[1], haystack),
34 3 => memrchr3(needle1:byteset[0], needle2:byteset[1], needle3:byteset[2], haystack),
35 _ => {
36 let table: [u8; 256] = build_table(byteset);
37 scalar::reverse_search_bytes(s:haystack, |b: u8| table[b as usize] != 0)
38 }
39 }
40}
41
42#[inline]
43pub(crate) fn find_not(haystack: &[u8], byteset: &[u8]) -> Option<usize> {
44 if haystack.is_empty() {
45 return None;
46 }
47 match byteset.len() {
48 0 => Some(0),
49 1 => scalar::inv_memchr(n1:byteset[0], haystack),
50 2 => scalar::forward_search_bytes(s:haystack, |b: u8| {
51 b != byteset[0] && b != byteset[1]
52 }),
53 3 => scalar::forward_search_bytes(s:haystack, |b: u8| {
54 b != byteset[0] && b != byteset[1] && b != byteset[2]
55 }),
56 _ => {
57 let table: [u8; 256] = build_table(byteset);
58 scalar::forward_search_bytes(s:haystack, |b: u8| table[b as usize] == 0)
59 }
60 }
61}
62#[inline]
63pub(crate) fn rfind_not(haystack: &[u8], byteset: &[u8]) -> Option<usize> {
64 if haystack.is_empty() {
65 return None;
66 }
67 match byteset.len() {
68 0 => Some(haystack.len() - 1),
69 1 => scalar::inv_memrchr(n1:byteset[0], haystack),
70 2 => scalar::reverse_search_bytes(s:haystack, |b: u8| {
71 b != byteset[0] && b != byteset[1]
72 }),
73 3 => scalar::reverse_search_bytes(s:haystack, |b: u8| {
74 b != byteset[0] && b != byteset[1] && b != byteset[2]
75 }),
76 _ => {
77 let table: [u8; 256] = build_table(byteset);
78 scalar::reverse_search_bytes(s:haystack, |b: u8| table[b as usize] == 0)
79 }
80 }
81}
82
83#[cfg(all(test, feature = "std", not(miri)))]
84mod tests {
85 use alloc::vec::Vec;
86
87 quickcheck::quickcheck! {
88 fn qc_byteset_forward_matches_naive(
89 haystack: Vec<u8>,
90 needles: Vec<u8>
91 ) -> bool {
92 super::find(&haystack, &needles)
93 == haystack.iter().position(|b| needles.contains(b))
94 }
95 fn qc_byteset_backwards_matches_naive(
96 haystack: Vec<u8>,
97 needles: Vec<u8>
98 ) -> bool {
99 super::rfind(&haystack, &needles)
100 == haystack.iter().rposition(|b| needles.contains(b))
101 }
102 fn qc_byteset_forward_not_matches_naive(
103 haystack: Vec<u8>,
104 needles: Vec<u8>
105 ) -> bool {
106 super::find_not(&haystack, &needles)
107 == haystack.iter().position(|b| !needles.contains(b))
108 }
109 fn qc_byteset_backwards_not_matches_naive(
110 haystack: Vec<u8>,
111 needles: Vec<u8>
112 ) -> bool {
113 super::rfind_not(&haystack, &needles)
114 == haystack.iter().rposition(|b| !needles.contains(b))
115 }
116 }
117}
118