summaryrefslogtreecommitdiffstats
path: root/decoder.c
diff options
context:
space:
mode:
Diffstat (limited to 'decoder.c')
-rw-r--r--decoder.c120
1 files changed, 50 insertions, 70 deletions
diff --git a/decoder.c b/decoder.c
index 8ef3942..971fc24 100644
--- a/decoder.c
+++ b/decoder.c
@@ -1,41 +1,35 @@
/* 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:
- 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.
+ 1. Redistributions of source code must retain the above copyright
+ notice, this list of conditions and the following disclaimer.
- You should have received a copy of the GNU General Public License
- along with this library. If not, see <http://www.gnu.org/licenses/>.
+ 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.
- 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.
+ 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.
*/
-static bool LZd_verify_trailer( struct LZ_decoder * const d )
+static int LZd_try_verify_trailer( struct LZ_decoder * const d )
{
File_trailer trailer;
- int size = Rd_read_data( d->rdec, trailer, Ft_size );
-
- if( size < Ft_size )
- return false;
+ if( Rd_available_bytes( d->rdec ) < Ft_size && !d->rdec->at_stream_end )
+ return 0;
+ d->verify_trailer_pending = false;
+ d->member_finished = true;
- return ( Ft_get_data_crc( trailer ) == LZd_crc( d ) &&
- Ft_get_data_size( trailer ) == LZd_data_position( d ) &&
- Ft_get_member_size( trailer ) == d->rdec->member_position );
+ if( Rd_read_data( d->rdec, trailer, Ft_size ) == Ft_size &&
+ Ft_get_data_crc( trailer ) == LZd_crc( d ) &&
+ Ft_get_data_size( trailer ) == LZd_data_position( d ) &&
+ Ft_get_member_size( trailer ) == d->rdec->member_position ) return 0;
+ return 3;
}
@@ -46,24 +40,17 @@ static int LZd_decode_member( struct LZ_decoder * const d )
{
struct Range_decoder * const rdec = d->rdec;
State * const state = &d->state;
-/* unsigned long long old_mpos = d->rdec->member_position; */
+ /* unsigned old_mpos = d->rdec->member_position; */
if( d->member_finished ) return 0;
if( !Rd_try_reload( rdec, false ) )
{ if( !rdec->at_stream_end ) return 0; else return 2; }
- if( d->verify_trailer_pending )
- {
- if( Rd_available_bytes( rdec ) < Ft_size && !rdec->at_stream_end )
- return 0;
- d->verify_trailer_pending = false;
- d->member_finished = true;
- if( LZd_verify_trailer( d ) ) return 0; else return 3;
- }
+ if( d->verify_trailer_pending ) return LZd_try_verify_trailer( d );
while( !Rd_finished( rdec ) )
{
const int pos_state = LZd_data_position( d ) & pos_state_mask;
-/* const unsigned long long mpos = d->rdec->member_position;
+ /* const unsigned mpos = d->rdec->member_position;
if( mpos - old_mpos > rd_min_available_bytes ) return 5;
old_mpos = mpos; */
if( !Rd_enough_available_bytes( rdec ) ) /* check unexpected eof */
@@ -71,19 +58,16 @@ static int LZd_decode_member( struct LZ_decoder * const d )
if( !LZd_enough_free_bytes( d ) ) return 0;
if( Rd_decode_bit( rdec, &d->bm_match[*state][pos_state] ) == 0 ) /* 1st bit */
{
- const uint8_t prev_byte = LZd_peek_prev( d );
+ Bit_model * const bm = d->bm_literal[get_lit_state(LZd_peek_prev( d ))];
if( St_is_char( *state ) )
{
*state -= ( *state < 4 ) ? *state : 3;
- LZd_put_byte( d, Rd_decode_tree( rdec,
- d->bm_literal[get_lit_state(prev_byte)], 8 ) );
+ LZd_put_byte( d, Rd_decode_tree8( rdec, bm ) );
}
else
{
*state -= ( *state < 10 ) ? 3 : 6;
- LZd_put_byte( d, Rd_decode_matched( rdec,
- d->bm_literal[get_lit_state(prev_byte)],
- LZd_peek( d, d->rep0 ) ) );
+ LZd_put_byte( d, Rd_decode_matched( rdec, bm, LZd_peek( d, d->rep0 ) ) );
}
}
else /* match or repeated match */
@@ -91,7 +75,13 @@ static int LZd_decode_member( struct LZ_decoder * const d )
int len;
if( Rd_decode_bit( rdec, &d->bm_rep[*state] ) != 0 ) /* 2nd bit */
{
- if( Rd_decode_bit( rdec, &d->bm_rep0[*state] ) != 0 ) /* 3rd bit */
+ if( Rd_decode_bit( rdec, &d->bm_rep0[*state] ) == 0 ) /* 3rd bit */
+ {
+ if( Rd_decode_bit( rdec, &d->bm_len[*state][pos_state] ) == 0 ) /* 4th bit */
+ { *state = St_set_short_rep( *state );
+ LZd_put_byte( d, LZd_peek( d, d->rep0 ) ); continue; }
+ }
+ else
{
unsigned distance;
if( Rd_decode_bit( rdec, &d->bm_rep1[*state] ) == 0 ) /* 4th bit */
@@ -107,43 +97,34 @@ static int LZd_decode_member( struct LZ_decoder * const d )
d->rep1 = d->rep0;
d->rep0 = distance;
}
- else
- {
- if( Rd_decode_bit( rdec, &d->bm_len[*state][pos_state] ) == 0 ) /* 4th bit */
- { *state = St_set_short_rep( *state );
- LZd_put_byte( d, LZd_peek( d, d->rep0 ) ); continue; }
- }
*state = St_set_rep( *state );
len = min_match_len + Rd_decode_len( rdec, &d->rep_len_model, pos_state );
}
else /* match */
{
- const unsigned rep0_saved = d->rep0;
- int dis_slot;
+ unsigned distance;
len = min_match_len + Rd_decode_len( rdec, &d->match_len_model, pos_state );
- dis_slot = Rd_decode_tree6( rdec, d->bm_dis_slot[get_len_state(len)] );
- if( dis_slot < start_dis_model ) d->rep0 = dis_slot;
- else
+ distance = Rd_decode_tree6( rdec, d->bm_dis_slot[get_len_state(len)] );
+ if( distance >= start_dis_model )
{
+ const unsigned dis_slot = distance;
const int direct_bits = ( dis_slot >> 1 ) - 1;
- d->rep0 = ( 2 | ( dis_slot & 1 ) ) << direct_bits;
+ distance = ( 2 | ( dis_slot & 1 ) ) << direct_bits;
if( dis_slot < end_dis_model )
- d->rep0 += Rd_decode_tree_reversed( rdec,
- d->bm_dis + d->rep0 - dis_slot - 1, direct_bits );
+ distance += Rd_decode_tree_reversed( rdec,
+ d->bm_dis + ( distance - dis_slot ), direct_bits );
else
{
- d->rep0 += Rd_decode( rdec, direct_bits - dis_align_bits ) << dis_align_bits;
- d->rep0 += Rd_decode_tree_reversed4( rdec, d->bm_align );
- if( d->rep0 == 0xFFFFFFFFU ) /* marker found */
+ distance +=
+ Rd_decode( rdec, direct_bits - dis_align_bits ) << dis_align_bits;
+ distance += Rd_decode_tree_reversed4( rdec, d->bm_align );
+ if( distance == 0xFFFFFFFFU ) /* marker found */
{
- d->rep0 = rep0_saved;
Rd_normalize( rdec );
if( len == min_match_len ) /* End Of Stream marker */
{
- if( Rd_available_bytes( rdec ) < Ft_size && !rdec->at_stream_end )
- { d->verify_trailer_pending = true; return 0; }
- d->member_finished = true;
- if( LZd_verify_trailer( d ) ) return 0; else return 3;
+ d->verify_trailer_pending = true;
+ return LZd_try_verify_trailer( d );
}
if( len == min_match_len + 1 ) /* Sync Flush marker */
{
@@ -154,11 +135,10 @@ static int LZd_decode_member( struct LZ_decoder * const d )
}
}
}
- d->rep3 = d->rep2; d->rep2 = d->rep1; d->rep1 = rep0_saved;
+ d->rep3 = d->rep2; d->rep2 = d->rep1; d->rep1 = d->rep0; d->rep0 = distance;
*state = St_set_match( *state );
if( d->rep0 >= d->dictionary_size ||
- ( d->rep0 >= d->cb.put && !d->pos_wrapped ) )
- return 1;
+ ( d->rep0 >= d->cb.put && !d->pos_wrapped ) ) return 1;
}
LZd_copy_block( d, d->rep0, len );
}