diff options
Diffstat (limited to 'decoder.c')
| -rw-r--r-- | decoder.c | 133 |
1 files changed, 67 insertions, 66 deletions
@@ -1,5 +1,5 @@ /* Lzlib - Compression library for the lzip format - Copyright (C) 2009-2018 Antonio Diaz Diaz. + Copyright (C) 2009-2019 Antonio Diaz Diaz. This library is free software. Redistribution and use in source and binary forms, with or without modification, are permitted provided @@ -19,16 +19,16 @@ static int LZd_try_verify_trailer( struct LZ_decoder * const d ) { - File_trailer trailer; - if( Rd_available_bytes( d->rdec ) < Ft_size && !d->rdec->at_stream_end ) + Lzip_trailer trailer; + if( Rd_available_bytes( d->rdec ) < Lt_size && !d->rdec->at_stream_end ) return 0; d->verify_trailer_pending = false; d->member_finished = true; - 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; + if( Rd_read_data( d->rdec, trailer, Lt_size ) == Lt_size && + Lt_get_data_crc( trailer ) == LZd_crc( d ) && + Lt_get_data_size( trailer ) == LZd_data_position( d ) && + Lt_get_member_size( trailer ) == d->rdec->member_position ) return 0; return 3; } @@ -49,15 +49,18 @@ static int LZd_decode_member( struct LZ_decoder * const d ) while( !Rd_finished( rdec ) ) { + int len; const int pos_state = LZd_data_position( d ) & pos_state_mask; /* 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 */ - { if( !rdec->at_stream_end ) return 0; else break; } + if( !Rd_enough_available_bytes( rdec ) ) /* check unexpected EOF */ + { if( !rdec->at_stream_end ) return 0; + if( Cb_empty( &rdec->cb ) ) break; } /* decode until EOF */ if( !LZd_enough_free_bytes( d ) ) return 0; - if( Rd_decode_bit( rdec, &d->bm_match[*state][pos_state] ) == 0 ) /* 1st bit */ + if( Rd_decode_bit( rdec, &d->bm_match[*state][pos_state] ) == 0 ) /* 1st bit */ { + /* literal byte */ Bit_model * const bm = d->bm_literal[get_lit_state(LZd_peek_prev( d ))]; if( St_is_char( *state ) ) { @@ -69,79 +72,77 @@ static int LZd_decode_member( struct LZ_decoder * const d ) *state -= ( *state < 10 ) ? 3 : 6; LZd_put_byte( d, Rd_decode_matched( rdec, bm, LZd_peek( d, d->rep0 ) ) ); } + continue; } - else /* match or repeated match */ + /* match or repeated match */ + if( Rd_decode_bit( rdec, &d->bm_rep[*state] ) != 0 ) /* 2nd bit */ { - 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; } - } + 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 */ + distance = d->rep1; else { - unsigned distance; - if( Rd_decode_bit( rdec, &d->bm_rep1[*state] ) == 0 ) /* 4th bit */ - distance = d->rep1; + if( Rd_decode_bit( rdec, &d->bm_rep2[*state] ) == 0 ) /* 5th bit */ + distance = d->rep2; else - { - if( Rd_decode_bit( rdec, &d->bm_rep2[*state] ) == 0 ) /* 5th bit */ - distance = d->rep2; - else - { distance = d->rep3; d->rep3 = d->rep2; } - d->rep2 = d->rep1; - } - d->rep1 = d->rep0; - d->rep0 = distance; + { distance = d->rep3; d->rep3 = d->rep2; } + d->rep2 = d->rep1; } - *state = St_set_rep( *state ); - len = min_match_len + Rd_decode_len( rdec, &d->rep_len_model, pos_state ); + d->rep1 = d->rep0; + d->rep0 = distance; } - else /* match */ + *state = St_set_rep( *state ); + len = min_match_len + Rd_decode_len( rdec, &d->rep_len_model, pos_state ); + } + else /* match */ + { + unsigned distance; + len = min_match_len + Rd_decode_len( rdec, &d->match_len_model, pos_state ); + distance = Rd_decode_tree6( rdec, d->bm_dis_slot[get_len_state(len)] ); + if( distance >= start_dis_model ) { - unsigned distance; - len = min_match_len + Rd_decode_len( rdec, &d->match_len_model, pos_state ); - 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; + distance = ( 2 | ( dis_slot & 1 ) ) << direct_bits; + if( dis_slot < end_dis_model ) + distance += Rd_decode_tree_reversed( rdec, + d->bm_dis + ( distance - dis_slot ), direct_bits ); + else { - const unsigned dis_slot = distance; - const int direct_bits = ( dis_slot >> 1 ) - 1; - distance = ( 2 | ( dis_slot & 1 ) ) << direct_bits; - if( dis_slot < end_dis_model ) - distance += Rd_decode_tree_reversed( rdec, - d->bm_dis + ( distance - dis_slot ), direct_bits ); - else + 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 */ { - 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 */ + Rd_normalize( rdec ); + if( len == min_match_len ) /* End Of Stream marker */ + { + d->verify_trailer_pending = true; + return LZd_try_verify_trailer( d ); + } + if( len == min_match_len + 1 ) /* Sync Flush marker */ { - Rd_normalize( rdec ); - if( len == min_match_len ) /* End Of Stream marker */ - { - d->verify_trailer_pending = true; - return LZd_try_verify_trailer( d ); - } - if( len == min_match_len + 1 ) /* Sync Flush marker */ - { - if( Rd_try_reload( rdec, true ) ) { /*old_mpos += 5;*/ continue; } - else { if( !rdec->at_stream_end ) return 0; else break; } - } - return 4; + if( Rd_try_reload( rdec, true ) ) { /*old_mpos += 5;*/ continue; } + else { if( !rdec->at_stream_end ) return 0; else break; } } + return 4; } } - 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; } - LZd_copy_block( d, d->rep0, len ); + 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; } + LZd_copy_block( d, d->rep0, len ); } return 2; } |