1//! Structures that wrap around various decoders to make decoding easier.
2
3use super::super::blocks::sequence_section::Sequence;
4use super::decodebuffer::DecodeBuffer;
5use crate::decoding::dictionary::Dictionary;
6use crate::fse::FSETable;
7use crate::huff0::HuffmanTable;
8use alloc::vec::Vec;
9
10use crate::blocks::sequence_section::{
11 MAX_LITERAL_LENGTH_CODE, MAX_MATCH_LENGTH_CODE, MAX_OFFSET_CODE,
12};
13
14/// A block level decoding buffer.
15pub struct DecoderScratch {
16 /// The decoder used for Huffman blocks.
17 pub huf: HuffmanScratch,
18 /// The decoder used for FSE blocks.
19 pub fse: FSEScratch,
20
21 pub buffer: DecodeBuffer,
22 pub offset_hist: [u32; 3],
23
24 pub literals_buffer: Vec<u8>,
25 pub sequences: Vec<Sequence>,
26 pub block_content_buffer: Vec<u8>,
27}
28
29impl DecoderScratch {
30 pub fn new(window_size: usize) -> DecoderScratch {
31 DecoderScratch {
32 huf: HuffmanScratch {
33 table: HuffmanTable::new(),
34 },
35 fse: FSEScratch {
36 offsets: FSETable::new(MAX_OFFSET_CODE),
37 of_rle: None,
38 literal_lengths: FSETable::new(MAX_LITERAL_LENGTH_CODE),
39 ll_rle: None,
40 match_lengths: FSETable::new(MAX_MATCH_LENGTH_CODE),
41 ml_rle: None,
42 },
43 buffer: DecodeBuffer::new(window_size),
44 offset_hist: [1, 4, 8],
45
46 block_content_buffer: Vec::new(),
47 literals_buffer: Vec::new(),
48 sequences: Vec::new(),
49 }
50 }
51
52 pub fn reset(&mut self, window_size: usize) {
53 self.offset_hist = [1, 4, 8];
54 self.literals_buffer.clear();
55 self.sequences.clear();
56 self.block_content_buffer.clear();
57
58 self.buffer.reset(window_size);
59
60 self.fse.literal_lengths.reset();
61 self.fse.match_lengths.reset();
62 self.fse.offsets.reset();
63 self.fse.ll_rle = None;
64 self.fse.ml_rle = None;
65 self.fse.of_rle = None;
66
67 self.huf.table.reset();
68 }
69
70 pub fn init_from_dict(&mut self, dict: &Dictionary) {
71 self.fse.reinit_from(&dict.fse);
72 self.huf.table.reinit_from(&dict.huf.table);
73 self.offset_hist = dict.offset_hist;
74 self.buffer.dict_content.clear();
75 self.buffer
76 .dict_content
77 .extend_from_slice(&dict.dict_content);
78 }
79}
80
81pub struct HuffmanScratch {
82 pub table: HuffmanTable,
83}
84
85impl HuffmanScratch {
86 pub fn new() -> HuffmanScratch {
87 HuffmanScratch {
88 table: HuffmanTable::new(),
89 }
90 }
91}
92
93impl Default for HuffmanScratch {
94 fn default() -> Self {
95 Self::new()
96 }
97}
98
99pub struct FSEScratch {
100 pub offsets: FSETable,
101 pub of_rle: Option<u8>,
102 pub literal_lengths: FSETable,
103 pub ll_rle: Option<u8>,
104 pub match_lengths: FSETable,
105 pub ml_rle: Option<u8>,
106}
107
108impl FSEScratch {
109 pub fn new() -> FSEScratch {
110 FSEScratch {
111 offsets: FSETable::new(MAX_OFFSET_CODE),
112 of_rle: None,
113 literal_lengths: FSETable::new(MAX_LITERAL_LENGTH_CODE),
114 ll_rle: None,
115 match_lengths: FSETable::new(MAX_MATCH_LENGTH_CODE),
116 ml_rle: None,
117 }
118 }
119
120 pub fn reinit_from(&mut self, other: &Self) {
121 self.offsets.reinit_from(&other.offsets);
122 self.literal_lengths.reinit_from(&other.literal_lengths);
123 self.match_lengths.reinit_from(&other.match_lengths);
124 self.of_rle = other.of_rle;
125 self.ll_rle = other.ll_rle;
126 self.ml_rle = other.ml_rle;
127 }
128}
129
130impl Default for FSEScratch {
131 fn default() -> Self {
132 Self::new()
133 }
134}
135