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-rw-r--r--decoder.h119
1 files changed, 83 insertions, 36 deletions
diff --git a/decoder.h b/decoder.h
index 0fe0110..0afdd83 100644
--- a/decoder.h
+++ b/decoder.h
@@ -1,5 +1,5 @@
/* Lunzip - Decompressor for the lzip format
- Copyright (C) 2010-2021 Antonio Diaz Diaz.
+ Copyright (C) 2010-2022 Antonio Diaz Diaz.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
@@ -101,12 +101,11 @@ static inline unsigned Rd_decode( struct Range_decoder * const rdec,
int i;
for( i = num_bits; i > 0; --i )
{
- bool bit;
Rd_normalize( rdec );
rdec->range >>= 1;
/* symbol <<= 1; */
/* if( rdec->code >= rdec->range ) { rdec->code -= rdec->range; symbol |= 1; } */
- bit = ( rdec->code >= rdec->range );
+ const bool bit = ( rdec->code >= rdec->range );
symbol <<= 1; symbol += bit;
rdec->code -= rdec->range & ( 0U - bit );
}
@@ -116,42 +115,75 @@ static inline unsigned Rd_decode( struct Range_decoder * const rdec,
static inline unsigned Rd_decode_bit( struct Range_decoder * const rdec,
Bit_model * const probability )
{
- uint32_t bound;
Rd_normalize( rdec );
- bound = ( rdec->range >> bit_model_total_bits ) * *probability;
+ const uint32_t bound = ( rdec->range >> bit_model_total_bits ) * *probability;
if( rdec->code < bound )
{
rdec->range = bound;
- *probability += (bit_model_total - *probability) >> bit_model_move_bits;
+ *probability += ( bit_model_total - *probability ) >> bit_model_move_bits;
return 0;
}
else
{
- rdec->range -= bound;
rdec->code -= bound;
+ rdec->range -= bound;
*probability -= *probability >> bit_model_move_bits;
return 1;
}
}
-static inline unsigned Rd_decode_tree3( struct Range_decoder * const rdec,
- Bit_model bm[] )
+static inline void Rd_decode_symbol_bit( struct Range_decoder * const rdec,
+ Bit_model * const probability, unsigned * symbol )
{
- unsigned symbol = 2 | Rd_decode_bit( rdec, &bm[1] );
- symbol = ( symbol << 1 ) | Rd_decode_bit( rdec, &bm[symbol] );
- symbol = ( symbol << 1 ) | Rd_decode_bit( rdec, &bm[symbol] );
- return symbol & 7;
+ Rd_normalize( rdec );
+ *symbol <<= 1;
+ const uint32_t bound = ( rdec->range >> bit_model_total_bits ) * *probability;
+ if( rdec->code < bound )
+ {
+ rdec->range = bound;
+ *probability += ( bit_model_total - *probability ) >> bit_model_move_bits;
+ }
+ else
+ {
+ rdec->code -= bound;
+ rdec->range -= bound;
+ *probability -= *probability >> bit_model_move_bits;
+ *symbol |= 1;
+ }
+ }
+
+static inline void Rd_decode_symbol_bit_reversed( struct Range_decoder * const rdec,
+ Bit_model * const probability, unsigned * model,
+ unsigned * symbol, const int i )
+ {
+ Rd_normalize( rdec );
+ *model <<= 1;
+ const uint32_t bound = ( rdec->range >> bit_model_total_bits ) * *probability;
+ if( rdec->code < bound )
+ {
+ rdec->range = bound;
+ *probability += ( bit_model_total - *probability ) >> bit_model_move_bits;
+ }
+ else
+ {
+ rdec->code -= bound;
+ rdec->range -= bound;
+ *probability -= *probability >> bit_model_move_bits;
+ *model |= 1;
+ *symbol |= 1 << i;
+ }
}
static inline unsigned Rd_decode_tree6( struct Range_decoder * const rdec,
Bit_model bm[] )
{
- unsigned symbol = 2 | Rd_decode_bit( rdec, &bm[1] );
- symbol = ( symbol << 1 ) | Rd_decode_bit( rdec, &bm[symbol] );
- symbol = ( symbol << 1 ) | Rd_decode_bit( rdec, &bm[symbol] );
- symbol = ( symbol << 1 ) | Rd_decode_bit( rdec, &bm[symbol] );
- symbol = ( symbol << 1 ) | Rd_decode_bit( rdec, &bm[symbol] );
- symbol = ( symbol << 1 ) | Rd_decode_bit( rdec, &bm[symbol] );
+ unsigned symbol = 1;
+ Rd_decode_symbol_bit( rdec, &bm[symbol], &symbol );
+ Rd_decode_symbol_bit( rdec, &bm[symbol], &symbol );
+ Rd_decode_symbol_bit( rdec, &bm[symbol], &symbol );
+ Rd_decode_symbol_bit( rdec, &bm[symbol], &symbol );
+ Rd_decode_symbol_bit( rdec, &bm[symbol], &symbol );
+ Rd_decode_symbol_bit( rdec, &bm[symbol], &symbol );
return symbol & 0x3F;
}
@@ -159,9 +191,14 @@ static inline unsigned Rd_decode_tree8( struct Range_decoder * const rdec,
Bit_model bm[] )
{
unsigned symbol = 1;
- int i;
- for( i = 0; i < 8; ++i )
- symbol = ( symbol << 1 ) | Rd_decode_bit( rdec, &bm[symbol] );
+ Rd_decode_symbol_bit( rdec, &bm[symbol], &symbol );
+ Rd_decode_symbol_bit( rdec, &bm[symbol], &symbol );
+ Rd_decode_symbol_bit( rdec, &bm[symbol], &symbol );
+ Rd_decode_symbol_bit( rdec, &bm[symbol], &symbol );
+ Rd_decode_symbol_bit( rdec, &bm[symbol], &symbol );
+ Rd_decode_symbol_bit( rdec, &bm[symbol], &symbol );
+ Rd_decode_symbol_bit( rdec, &bm[symbol], &symbol );
+ Rd_decode_symbol_bit( rdec, &bm[symbol], &symbol );
return symbol & 0xFF;
}
@@ -173,21 +210,19 @@ Rd_decode_tree_reversed( struct Range_decoder * const rdec,
unsigned symbol = 0;
int i;
for( i = 0; i < num_bits; ++i )
- {
- const unsigned bit = Rd_decode_bit( rdec, &bm[model] );
- model <<= 1; model += bit;
- symbol |= ( bit << i );
- }
+ Rd_decode_symbol_bit_reversed( rdec, &bm[model], &model, &symbol, i );
return symbol;
}
static inline unsigned
Rd_decode_tree_reversed4( struct Range_decoder * const rdec, Bit_model bm[] )
{
- unsigned symbol = Rd_decode_bit( rdec, &bm[1] );
- symbol += Rd_decode_bit( rdec, &bm[2+symbol] ) << 1;
- symbol += Rd_decode_bit( rdec, &bm[4+symbol] ) << 2;
- symbol += Rd_decode_bit( rdec, &bm[8+symbol] ) << 3;
+ unsigned model = 1;
+ unsigned symbol = 0;
+ Rd_decode_symbol_bit_reversed( rdec, &bm[model], &model, &symbol, 0 );
+ Rd_decode_symbol_bit_reversed( rdec, &bm[model], &model, &symbol, 1 );
+ Rd_decode_symbol_bit_reversed( rdec, &bm[model], &model, &symbol, 2 );
+ Rd_decode_symbol_bit_reversed( rdec, &bm[model], &model, &symbol, 3 );
return symbol;
}
@@ -210,11 +245,24 @@ static inline unsigned Rd_decode_len( struct Range_decoder * const rdec,
struct Len_model * const lm,
const int pos_state )
{
+ Bit_model * bm;
+ unsigned mask, offset, symbol = 1;
+
if( Rd_decode_bit( rdec, &lm->choice1 ) == 0 )
- return Rd_decode_tree3( rdec, lm->bm_low[pos_state] );
+ { bm = lm->bm_low[pos_state]; mask = 7; offset = 0; goto len3; }
if( Rd_decode_bit( rdec, &lm->choice2 ) == 0 )
- return len_low_symbols + Rd_decode_tree3( rdec, lm->bm_mid[pos_state] );
- return len_low_symbols + len_mid_symbols + Rd_decode_tree8( rdec, lm->bm_high );
+ { bm = lm->bm_mid[pos_state]; mask = 7; offset = len_low_symbols; goto len3; }
+ bm = lm->bm_high; mask = 0xFF; offset = len_low_symbols + len_mid_symbols;
+ Rd_decode_symbol_bit( rdec, &bm[symbol], &symbol );
+ Rd_decode_symbol_bit( rdec, &bm[symbol], &symbol );
+ Rd_decode_symbol_bit( rdec, &bm[symbol], &symbol );
+ Rd_decode_symbol_bit( rdec, &bm[symbol], &symbol );
+ Rd_decode_symbol_bit( rdec, &bm[symbol], &symbol );
+len3:
+ Rd_decode_symbol_bit( rdec, &bm[symbol], &symbol );
+ Rd_decode_symbol_bit( rdec, &bm[symbol], &symbol );
+ Rd_decode_symbol_bit( rdec, &bm[symbol], &symbol );
+ return ( symbol & mask ) + min_match_len + offset;
}
@@ -291,11 +339,10 @@ static inline void LZd_copy_block( struct LZ_decoder * const d,
}
}
+/* block is (at least partially) outside of the buffer */
static inline void LZd_copy_block2( struct LZ_decoder * const d,
const unsigned distance, unsigned len )
{
- if( d->buffer_size > distance ) /* block is in buffer */
- { LZd_copy_block( d, distance, len ); return; }
if( len < d->buffer_size - d->pos ) /* no wrap */
{
const unsigned offset = distance + 1 + d->stream_pos - d->pos;
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-16 01:10:13 +0000