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hacked parity context version for arm code

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This commit is contained in:
Dennis Ranke
2021-12-30 11:49:59 +01:00
parent 3902425922
commit 7d40bb8123
1 changed files with 22 additions and 16 deletions
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38
src/lz.rs
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@@ -9,29 +9,32 @@ pub enum Op {
impl Op { impl Op {
pub fn encode(&self, coder: &mut dyn EntropyCoder, state: &mut CoderState) { pub fn encode(&self, coder: &mut dyn EntropyCoder, state: &mut CoderState) {
let base_context = 256 * (state.pos & 3);
match self { match self {
&Op::Literal(lit) => { &Op::Literal(lit) => {
encode_bit(coder, state, 0, false); encode_bit(coder, state, base_context, false);
let mut context_index = 1; let mut context_index = 1;
for i in (0..8).rev() { for i in (0..8).rev() {
let bit = (lit >> i) & 1 != 0; let bit = (lit >> i) & 1 != 0;
encode_bit(coder, state, context_index, bit); encode_bit(coder, state, base_context + context_index, bit);
context_index = (context_index << 1) | bit as usize; context_index = (context_index << 1) | bit as usize;
} }
state.pos += 1;
state.prev_was_match = false; state.prev_was_match = false;
} }
&Op::Match { offset, len } => { &Op::Match { offset, len } => {
encode_bit(coder, state, 0, true); encode_bit(coder, state, base_context, true);
if !state.prev_was_match { if !state.prev_was_match {
encode_bit(coder, state, 256, offset != state.last_offset); encode_bit(coder, state, 1024, offset != state.last_offset);
} else { } else {
assert!(offset != state.last_offset); assert!(offset != state.last_offset);
} }
if offset != state.last_offset { if offset != state.last_offset {
encode_length(coder, state, 257, offset + 1); encode_length(coder, state, 1025, offset + 1);
state.last_offset = offset; state.last_offset = offset;
} }
encode_length(coder, state, 257 + 64, len); encode_length(coder, state, 1025 + 64, len);
state.pos += len as usize;
state.prev_was_match = true; state.prev_was_match = true;
} }
} }
@@ -39,11 +42,11 @@ impl Op {
} }
pub fn encode_eof(coder: &mut dyn EntropyCoder, state: &mut CoderState) { pub fn encode_eof(coder: &mut dyn EntropyCoder, state: &mut CoderState) {
encode_bit(coder, state, 0, true); encode_bit(coder, state, 256 * (state.pos & 3), true);
if !state.prev_was_match { if !state.prev_was_match {
encode_bit(coder, state, 256, true); encode_bit(coder, state, 1024, true);
} }
encode_length(coder, state, 257, 1); encode_length(coder, state, 1025, 1);
} }
fn encode_bit( fn encode_bit(
@@ -77,14 +80,16 @@ fn encode_length(
pub struct CoderState { pub struct CoderState {
contexts: ContextState, contexts: ContextState,
last_offset: u32, last_offset: u32,
pos: usize,
prev_was_match: bool, prev_was_match: bool,
} }
impl CoderState { impl CoderState {
pub fn new() -> CoderState { pub fn new() -> CoderState {
CoderState { CoderState {
contexts: ContextState::new(1 + 255 + 1 + 64 + 64), contexts: ContextState::new((1 + 255) * 4 + 1 + 64 + 64),
last_offset: 0, last_offset: 0,
pos: 0,
prev_was_match: false, prev_was_match: false,
} }
} }
@@ -96,7 +101,7 @@ impl CoderState {
pub fn unpack(packed_data: &[u8], use_bitstream: bool) -> Vec<u8> { pub fn unpack(packed_data: &[u8], use_bitstream: bool) -> Vec<u8> {
let mut decoder = RansDecoder::new(packed_data, use_bitstream); let mut decoder = RansDecoder::new(packed_data, use_bitstream);
let mut contexts = ContextState::new(1 + 255 + 1 + 64 + 64); let mut contexts = ContextState::new((1 + 255) * 4 + 1 + 64 + 64);
let mut result = vec![]; let mut result = vec![];
let mut offset = 0; let mut offset = 0;
let mut prev_was_match = false; let mut prev_was_match = false;
@@ -119,14 +124,15 @@ pub fn unpack(packed_data: &[u8], use_bitstream: bool) -> Vec<u8> {
} }
loop { loop {
if decoder.decode_with_context(&mut contexts.context_mut(0)) { let base_context = 256 * (result.len() & 3);
if prev_was_match || decoder.decode_with_context(&mut contexts.context_mut(256)) { if decoder.decode_with_context(&mut contexts.context_mut(base_context)) {
offset = decode_length(&mut decoder, &mut contexts, 257) - 1; if prev_was_match || decoder.decode_with_context(&mut contexts.context_mut(1024)) {
offset = decode_length(&mut decoder, &mut contexts, 1025) - 1;
if offset == 0 { if offset == 0 {
break; break;
} }
} }
let length = decode_length(&mut decoder, &mut contexts, 257 + 64); let length = decode_length(&mut decoder, &mut contexts, 1025 + 64);
for _ in 0..length { for _ in 0..length {
result.push(result[result.len() - offset]); result.push(result[result.len() - offset]);
} }
@@ -135,7 +141,7 @@ pub fn unpack(packed_data: &[u8], use_bitstream: bool) -> Vec<u8> {
let mut context_index = 1; let mut context_index = 1;
let mut byte = 0; let mut byte = 0;
for i in (0..8).rev() { for i in (0..8).rev() {
let bit = decoder.decode_with_context(&mut contexts.context_mut(context_index)); let bit = decoder.decode_with_context(&mut contexts.context_mut(base_context + context_index));
context_index = (context_index << 1) | bit as usize; context_index = (context_index << 1) | bit as usize;
byte |= (bit as u8) << i; byte |= (bit as u8) << i;
} }