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implement parsing packer + fix huge bug in match finder

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This commit is contained in:
Dennis Ranke
2021-11-24 09:28:18 +01:00
parent 470b778340
commit 11b43f9bc4
7 changed files with 277 additions and 95 deletions
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25
src/greedy_packer.rs
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@@ -1,9 +1,11 @@
use crate::lz::LzCoder;
use crate::lz;
use crate::match_finder::MatchFinder;
use crate::rans::RansCoder;
pub fn pack(data: &[u8]) -> Vec<u8> {
let match_finder = MatchFinder::new(data);
let mut lz = LzCoder::new();
let mut rans_coder = RansCoder::new();
let mut state = lz::CoderState::new();
let mut pos = 0;
while pos < data.len() {
@@ -12,14 +14,18 @@ pub fn pack(data: &[u8]) -> Vec<u8> {
let max_offset = 1 << (m.length * 3 - 1).min(31);
let offset = pos - m.pos;
if offset < max_offset {
lz.encode_match(offset, m.length);
lz::Op::Match {
offset: offset as u32,
len: m.length as u32,
}
.encode(&mut rans_coder, &mut state);
pos += m.length;
encoded_match = true;
}
}
if !encoded_match {
let offset = lz.last_offset();
let offset = state.last_offset() as usize;
if offset != 0 {
let length = data[pos..]
.iter()
@@ -27,7 +33,11 @@ pub fn pack(data: &[u8]) -> Vec<u8> {
.take_while(|(a, b)| a == b)
.count();
if length > 0 {
lz.encode_match(offset, length);
lz::Op::Match {
offset: offset as u32,
len: length as u32,
}
.encode(&mut rans_coder, &mut state);
pos += length;
encoded_match = true;
}
@@ -35,10 +45,11 @@ pub fn pack(data: &[u8]) -> Vec<u8> {
}
if !encoded_match {
lz.encode_literal(data[pos]);
lz::Op::Literal(data[pos]).encode(&mut rans_coder, &mut state);
pos += 1;
}
}
lz.finish()
lz::encode_eof(&mut rans_coder, &mut state);
rans_coder.finish()
}