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-rw-r--r--decoder.h206
1 files changed, 102 insertions, 104 deletions
diff --git a/decoder.h b/decoder.h
index a14156e..8e422a8 100644
--- a/decoder.h
+++ b/decoder.h
@@ -1,28 +1,20 @@
/* Lzlib - Compression library for the lzip format
- Copyright (C) 2009-2016 Antonio Diaz Diaz.
+ Copyright (C) 2009-2017 Antonio Diaz Diaz.
- This library is free software: you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation, either version 2 of the License, or
- (at your option) any later version.
+ This library is free software. Redistribution and use in source and
+ binary forms, with or without modification, are permitted provided
+ that the following conditions are met:
+
+ 1. Redistributions of source code must retain the above copyright
+ notice, this list of conditions and the following disclaimer.
+
+ 2. Redistributions in binary form must reproduce the above copyright
+ notice, this list of conditions and the following disclaimer in the
+ documentation and/or other materials provided with the distribution.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
-
- You should have received a copy of the GNU General Public License
- along with this library. If not, see <http://www.gnu.org/licenses/>.
-
- As a special exception, you may use this file as part of a free
- software library without restriction. Specifically, if other files
- instantiate templates or use macros or inline functions from this
- file, or you compile this file and link it with other files to
- produce an executable, this file does not by itself cause the
- resulting executable to be covered by the GNU General Public
- License. This exception does not however invalidate any other
- reasons why the executable file might be covered by the GNU General
- Public License.
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
*/
enum { rd_min_available_bytes = 8 };
@@ -84,7 +76,7 @@ static inline void Rd_reset( struct Range_decoder * const rdec )
number of bytes skipped. Returns true if it finds a valid header.
*/
static bool Rd_find_header( struct Range_decoder * const rdec,
- int * const skippedp )
+ unsigned * const skippedp )
{
*skippedp = 0;
while( rdec->cb.get != rdec->cb.put )
@@ -158,34 +150,30 @@ static bool Rd_try_reload( struct Range_decoder * const rdec, const bool force )
static inline void Rd_normalize( struct Range_decoder * const rdec )
{
if( rdec->range <= 0x00FFFFFFU )
- {
- rdec->range <<= 8;
- rdec->code = (rdec->code << 8) | Rd_get_byte( rdec );
- }
+ { rdec->range <<= 8; rdec->code = (rdec->code << 8) | Rd_get_byte( rdec ); }
}
-static inline int Rd_decode( struct Range_decoder * const rdec,
- const int num_bits )
+static inline unsigned Rd_decode( struct Range_decoder * const rdec,
+ const int num_bits )
{
- int symbol = 0;
+ unsigned symbol = 0;
int i;
for( i = num_bits; i > 0; --i )
{
- uint32_t mask;
+ bool bit;
Rd_normalize( rdec );
rdec->range >>= 1;
/* symbol <<= 1; */
/* if( rdec->code >= rdec->range ) { rdec->code -= rdec->range; symbol |= 1; } */
- mask = 0U - (rdec->code < rdec->range);
- rdec->code -= rdec->range;
- rdec->code += rdec->range & mask;
- symbol = (symbol << 1) + (mask + 1);
+ bit = ( rdec->code >= rdec->range );
+ symbol = ( symbol << 1 ) + bit;
+ rdec->code -= rdec->range & ( 0U - bit );
}
return symbol;
}
-static inline int Rd_decode_bit( struct Range_decoder * const rdec,
- Bit_model * const probability )
+static inline unsigned Rd_decode_bit( struct Range_decoder * const rdec,
+ Bit_model * const probability )
{
uint32_t bound;
Rd_normalize( rdec );
@@ -205,20 +193,20 @@ static inline int Rd_decode_bit( struct Range_decoder * const rdec,
}
}
-static inline int Rd_decode_tree( struct Range_decoder * const rdec,
- Bit_model bm[], const int num_bits )
+static inline unsigned Rd_decode_tree3( struct Range_decoder * const rdec,
+ Bit_model bm[] )
{
- int symbol = 1;
- int i;
- for( i = num_bits; i > 0; --i )
- symbol = ( symbol << 1 ) | Rd_decode_bit( rdec, &bm[symbol] );
- return symbol - (1 << num_bits);
+ unsigned symbol = 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] );
+ return symbol & 7;
}
-static inline int Rd_decode_tree6( struct Range_decoder * const rdec,
- Bit_model bm[] )
+static inline unsigned Rd_decode_tree6( struct Range_decoder * const rdec,
+ Bit_model bm[] )
{
- int symbol = 1;
+ unsigned symbol = 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] );
@@ -228,69 +216,69 @@ static inline int Rd_decode_tree6( struct Range_decoder * const rdec,
return symbol & 0x3F;
}
-static inline int Rd_decode_tree_reversed( struct Range_decoder * const rdec,
- Bit_model bm[], const int num_bits )
+static inline unsigned Rd_decode_tree8( struct Range_decoder * const rdec,
+ Bit_model bm[] )
{
- int model = 1;
- int symbol = 0;
+ unsigned symbol = 1;
+ int i;
+ for( i = 0; i < 8; ++i )
+ symbol = ( symbol << 1 ) | Rd_decode_bit( rdec, &bm[symbol] );
+ return symbol & 0xFF;
+ }
+
+static inline unsigned
+Rd_decode_tree_reversed( struct Range_decoder * const rdec,
+ Bit_model bm[], const int num_bits )
+ {
+ unsigned model = 1;
+ unsigned symbol = 0;
int i;
for( i = 0; i < num_bits; ++i )
{
- const bool bit = Rd_decode_bit( rdec, &bm[model] );
- model <<= 1;
- if( bit ) { ++model; symbol |= (1 << i); }
+ const unsigned bit = Rd_decode_bit( rdec, &bm[model] );
+ model = ( model << 1 ) + bit;
+ symbol |= ( bit << i );
}
return symbol;
}
-static inline int Rd_decode_tree_reversed4( struct Range_decoder * const rdec,
- Bit_model bm[] )
+static inline unsigned
+Rd_decode_tree_reversed4( struct Range_decoder * const rdec, Bit_model bm[] )
{
- int model = 1;
- int symbol = Rd_decode_bit( rdec, &bm[model] );
- int bit;
- model = (model << 1) + symbol;
+ unsigned symbol = Rd_decode_bit( rdec, &bm[1] );
+ unsigned model = 2 + symbol;
+ unsigned bit = Rd_decode_bit( rdec, &bm[model] );
+ model = ( model << 1 ) + bit; symbol |= ( bit << 1 );
bit = Rd_decode_bit( rdec, &bm[model] );
- model = (model << 1) + bit; symbol |= (bit << 1);
- bit = Rd_decode_bit( rdec, &bm[model] );
- model = (model << 1) + bit; symbol |= (bit << 2);
- if( Rd_decode_bit( rdec, &bm[model] ) ) symbol |= 8;
+ model = ( model << 1 ) + bit; symbol |= ( bit << 2 );
+ symbol |= ( Rd_decode_bit( rdec, &bm[model] ) << 3 );
return symbol;
}
-static inline int Rd_decode_matched( struct Range_decoder * const rdec,
- Bit_model bm[], int match_byte )
+static inline unsigned Rd_decode_matched( struct Range_decoder * const rdec,
+ Bit_model bm[], unsigned match_byte )
{
- Bit_model * const bm1 = bm + 0x100;
- int symbol = 1;
- while( symbol < 0x100 )
+ unsigned symbol = 1;
+ unsigned mask = 0x100;
+ while( true )
{
- int match_bit, bit;
- match_byte <<= 1;
- match_bit = match_byte & 0x100;
- bit = Rd_decode_bit( rdec, &bm1[match_bit+symbol] );
- symbol = ( symbol << 1 ) | bit;
- if( match_bit != bit << 8 )
- {
- while( symbol < 0x100 )
- symbol = ( symbol << 1 ) | Rd_decode_bit( rdec, &bm[symbol] );
- break;
- }
+ const unsigned match_bit = ( match_byte <<= 1 ) & mask;
+ const unsigned bit = Rd_decode_bit( rdec, &bm[symbol+match_bit+mask] );
+ symbol = ( symbol << 1 ) + bit;
+ if( symbol > 0xFF ) return symbol & 0xFF;
+ mask &= ~(match_bit ^ (bit << 8)); /* if( match_bit != bit ) mask = 0; */
}
- return symbol & 0xFF;
}
-static inline int Rd_decode_len( struct Range_decoder * const rdec,
- struct Len_model * const lm,
- const int pos_state )
+static inline unsigned Rd_decode_len( struct Range_decoder * const rdec,
+ struct Len_model * const lm,
+ const int pos_state )
{
if( Rd_decode_bit( rdec, &lm->choice1 ) == 0 )
- return Rd_decode_tree( rdec, lm->bm_low[pos_state], len_low_bits );
+ return Rd_decode_tree3( rdec, lm->bm_low[pos_state] );
if( Rd_decode_bit( rdec, &lm->choice2 ) == 0 )
- return len_low_symbols +
- Rd_decode_tree( rdec, lm->bm_mid[pos_state], len_mid_bits );
- return len_low_symbols + len_mid_symbols +
- Rd_decode_tree( rdec, lm->bm_high, len_high_bits );
+ 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 );
}
@@ -320,7 +308,7 @@ struct LZ_decoder
Bit_model bm_rep2[states];
Bit_model bm_len[states][pos_states];
Bit_model bm_dis_slot[len_states][1<<dis_slot_bits];
- Bit_model bm_dis[modeled_distances-end_dis_model];
+ Bit_model bm_dis[modeled_distances-end_dis_model+1];
Bit_model bm_align[dis_align_size];
struct Len_model match_len_model;
@@ -332,15 +320,16 @@ static inline bool LZd_enough_free_bytes( const struct LZ_decoder * const d )
static inline uint8_t LZd_peek_prev( const struct LZ_decoder * const d )
{
- const unsigned i = ( ( d->cb.put > 0 ) ? d->cb.put : d->cb.buffer_size ) - 1;
- return d->cb.buffer[i];
+ if( d->cb.put > 0 ) return d->cb.buffer[d->cb.put-1];
+ if( d->pos_wrapped ) return d->cb.buffer[d->cb.buffer_size-1];
+ return 0; /* prev_byte of first byte */
}
static inline uint8_t LZd_peek( const struct LZ_decoder * const d,
const unsigned distance )
{
- unsigned i = d->cb.put - distance - 1;
- if( d->cb.put <= distance ) i += d->cb.buffer_size;
+ const unsigned i = ( ( d->cb.put > distance ) ? 0 : d->cb.buffer_size ) +
+ d->cb.put - distance - 1;
return d->cb.buffer[i];
}
@@ -355,18 +344,28 @@ static inline void LZd_put_byte( struct LZ_decoder * const d, const uint8_t b )
static inline void LZd_copy_block( struct LZ_decoder * const d,
const unsigned distance, unsigned len )
{
- unsigned i = d->cb.put - distance - 1;
- bool fast;
- if( d->cb.put <= distance )
- { i += d->cb.buffer_size;
- fast = ( len <= d->cb.buffer_size - i && len <= i - d->cb.put ); }
+ unsigned lpos = d->cb.put, i = lpos - distance - 1;
+ bool fast, fast2;
+ if( lpos > distance )
+ {
+ fast = ( len < d->cb.buffer_size - lpos );
+ fast2 = ( fast && len <= lpos - i );
+ }
else
- fast = ( len < d->cb.buffer_size - d->cb.put && len <= d->cb.put - i );
- if( fast ) /* no wrap, no overlap */
{
- CRC32_update_buf( &d->crc, d->cb.buffer + i, len );
- memcpy( d->cb.buffer + d->cb.put, d->cb.buffer + i, len );
- d->cb.put += len;
+ i += d->cb.buffer_size;
+ fast = ( len < d->cb.buffer_size - i ); /* (i == pos) may happen */
+ fast2 = ( fast && len <= i - lpos );
+ }
+ if( fast ) /* no wrap */
+ {
+ const unsigned tlen = len;
+ if( fast2 ) /* no wrap, no overlap */
+ memcpy( d->cb.buffer + lpos, d->cb.buffer + i, len );
+ else
+ for( ; len > 0; --len ) d->cb.buffer[lpos++] = d->cb.buffer[i++];
+ CRC32_update_buf( &d->crc, d->cb.buffer + d->cb.put, tlen );
+ d->cb.put += tlen;
}
else for( ; len > 0; --len )
{
@@ -402,11 +401,10 @@ static inline bool LZd_init( struct LZ_decoder * const d,
Bm_array_init( d->bm_rep2, states );
Bm_array_init( d->bm_len[0], states * pos_states );
Bm_array_init( d->bm_dis_slot[0], len_states * (1 << dis_slot_bits) );
- Bm_array_init( d->bm_dis, modeled_distances - end_dis_model );
+ Bm_array_init( d->bm_dis, modeled_distances - end_dis_model + 1 );
Bm_array_init( d->bm_align, dis_align_size );
Lm_init( &d->match_len_model );
Lm_init( &d->rep_len_model );
- d->cb.buffer[d->cb.buffer_size-1] = 0; /* prev_byte of first byte */
return true;
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-11 19:41:17 +0000