diff options
Diffstat (limited to 'decoder.c')
| -rw-r--r-- | decoder.c | 248 |
1 files changed, 248 insertions, 0 deletions
diff --git a/decoder.c b/decoder.c new file mode 100644 index 0000000..e6af722 --- /dev/null +++ b/decoder.c @@ -0,0 +1,248 @@ +/* Lunzip - Decompressor for lzip files + Copyright (C) 2010 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 + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program 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 program. If not, see <http://www.gnu.org/licenses/>. +*/ + +#define _FILE_OFFSET_BITS 64 + +#include <errno.h> +#include <stdbool.h> +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#include "lunzip.h" +#include "decoder.h" + + +CRC32 crc32; + +bool Rd_read_block( struct Range_decoder * const rdec ) + { + if( !rdec->at_stream_end ) + { + rdec->stream_pos = readblock( rdec->infd, rdec->buffer, rd_buffer_size ); + if( rdec->stream_pos != rd_buffer_size && errno ) + { show_error( "Read error", errno, false ); cleanup_and_fail( 1 ); } + rdec->at_stream_end = ( rdec->stream_pos < rd_buffer_size ); + rdec->partial_member_pos += rdec->pos; + rdec->pos = 0; + } + return rdec->pos < rdec->stream_pos; + } + + +void LZd_flush_data( struct LZ_decoder * const decoder ) + { + const int size = decoder->pos - decoder->stream_pos; + if( size > 0 ) + { + CRC32_update_buf( &decoder->crc_, decoder->buffer + decoder->stream_pos, size ); + if( decoder->outfd >= 0 && + writeblock( decoder->outfd, decoder->buffer + decoder->stream_pos, size ) != size ) + { show_error( "write error", errno, false ); cleanup_and_fail( 1 ); } + if( decoder->pos >= decoder->buffer_size ) + { decoder->partial_data_pos += decoder->pos; decoder->pos = 0; } + decoder->stream_pos = decoder->pos; + } + } + + +bool LZd_verify_trailer( struct LZ_decoder * const decoder, + struct Pretty_print * const pp ) + { + int i; + File_trailer trailer; + const int trailer_size = Ft_versioned_size( decoder->member_version ); + const long long member_size = + Rd_member_position( decoder->range_decoder ) + trailer_size; + bool error = false; + + for( i = 0; i < trailer_size && !error; ++i ) + { + if( !Rd_finished( decoder->range_decoder ) ) + trailer[i] = Rd_get_byte( decoder->range_decoder ); + else + { + error = true; + if( pp->verbosity >= 0 ) + { + Pp_show_msg( pp, 0 ); + fprintf( stderr, "Trailer truncated at trailer position %d;" + " some checks may fail.\n", i ); + } + for( ; i < trailer_size; ++i ) trailer[i] = 0; + } + } + if( decoder->member_version == 0 ) Ft_set_member_size( trailer, member_size ); + if( !Rd_code_is_zero( decoder->range_decoder ) ) + { + error = true; + Pp_show_msg( pp, "Range decoder final code is not zero" ); + } + if( Ft_get_data_crc( trailer ) != LZd_crc( decoder ) ) + { + error = true; + if( pp->verbosity >= 0 ) + { + Pp_show_msg( pp, 0 ); + fprintf( stderr, "CRC mismatch; trailer says %08X, data CRC is %08X.\n", + (unsigned int)Ft_get_data_crc( trailer ), + (unsigned int)LZd_crc( decoder ) ); + } + } + if( Ft_get_data_size( trailer ) != LZd_data_position( decoder ) ) + { + error = true; + if( pp->verbosity >= 0 ) + { + Pp_show_msg( pp, 0 ); + fprintf( stderr, "Data size mismatch; trailer says %lld, data size is %lld (0x%llX).\n", + Ft_get_data_size( trailer ), LZd_data_position( decoder ), LZd_data_position( decoder ) ); + } + } + if( Ft_get_member_size( trailer ) != member_size ) + { + error = true; + if( pp->verbosity >= 0 ) + { + Pp_show_msg( pp, 0 ); + fprintf( stderr, "Member size mismatch; trailer says %lld, member size is %lld (0x%llX).\n", + Ft_get_member_size( trailer ), member_size, member_size ); + } + } + if( !error && pp->verbosity >= 4 && LZd_data_position( decoder ) > 0 && member_size > 0 ) + fprintf( stderr, "%6.3f:1, %6.3f bits/byte, %5.2f%% saved. ", + (double)LZd_data_position( decoder ) / member_size, + ( 8.0 * member_size ) / LZd_data_position( decoder ), + 100.0 * ( 1.0 - ( (double)member_size / LZd_data_position( decoder ) ) ) ); + if( !error && pp->verbosity >= 3 ) + fprintf( stderr, "data CRC %08X, data size %9lld, member size %8lld. ", + (unsigned int)Ft_get_data_crc( trailer ), + Ft_get_data_size( trailer ), Ft_get_member_size( trailer ) ); + return !error; + } + + +/* Return value: 0 = OK, 1 = decoder error, 2 = unexpected EOF, + 3 = trailer error, 4 = unknown marker found. */ +int LZd_decode_member( struct LZ_decoder * const decoder, + struct Pretty_print * const pp ) + { + unsigned int rep0 = 0; /* rep[0-3] latest four distances */ + unsigned int rep1 = 0; /* used for efficient coding of */ + unsigned int rep2 = 0; /* repeated distances */ + unsigned int rep3 = 0; + State state = 0; + Rd_load( decoder->range_decoder ); + + while( true ) + { + const int pos_state = LZd_data_position( decoder ) & pos_state_mask; + if( Rd_finished( decoder->range_decoder ) ) + { LZd_flush_data( decoder ); return 2; } + if( Rd_decode_bit( decoder->range_decoder, &decoder->bm_match[state][pos_state] ) == 0 ) + { + const uint8_t prev_byte = LZd_get_prev_byte( decoder ); + if( St_is_char( state ) ) + LZd_put_byte( decoder, Lid_decode( &decoder->literal_decoder, + decoder->range_decoder, prev_byte ) ); + else + LZd_put_byte( decoder, Lid_decode_matched( &decoder->literal_decoder, + decoder->range_decoder, prev_byte, LZd_get_byte( decoder, rep0 ) ) ); + St_set_char( &state ); + } + else + { + int len; + if( Rd_decode_bit( decoder->range_decoder, &decoder->bm_rep[state] ) == 1 ) + { + len = 0; + if( Rd_decode_bit( decoder->range_decoder, &decoder->bm_rep0[state] ) == 1 ) + { + unsigned int distance; + if( Rd_decode_bit( decoder->range_decoder, &decoder->bm_rep1[state] ) == 0 ) + distance = rep1; + else + { + if( Rd_decode_bit( decoder->range_decoder, &decoder->bm_rep2[state] ) == 0 ) + distance = rep2; + else { distance = rep3; rep3 = rep2; } + rep2 = rep1; + } + rep1 = rep0; + rep0 = distance; + } + else + { + if( Rd_decode_bit( decoder->range_decoder, &decoder->bm_len[state][pos_state] ) == 0 ) + { St_set_short_rep( &state ); len = 1; } + } + if( len == 0 ) + { + St_set_rep( &state ); + len = min_match_len + Led_decode( &decoder->rep_match_len_decoder, decoder->range_decoder, pos_state ); + } + } + else + { + int dis_slot; + const unsigned int rep0_saved = rep0; + len = min_match_len + Led_decode( &decoder->len_decoder, decoder->range_decoder, pos_state ); + dis_slot = Rd_decode_tree( decoder->range_decoder, decoder->bm_dis_slot[get_dis_state(len)], dis_slot_bits ); + if( dis_slot < start_dis_model ) rep0 = dis_slot; + else + { + const int direct_bits = ( dis_slot >> 1 ) - 1; + rep0 = ( 2 | ( dis_slot & 1 ) ) << direct_bits; + if( dis_slot < end_dis_model ) + rep0 += Rd_decode_tree_reversed( decoder->range_decoder, decoder->bm_dis + rep0 - dis_slot, direct_bits ); + else + { + rep0 += Rd_decode( decoder->range_decoder, direct_bits - dis_align_bits ) << dis_align_bits; + rep0 += Rd_decode_tree_reversed( decoder->range_decoder, decoder->bm_align, dis_align_bits ); + if( rep0 == 0xFFFFFFFFU ) /* Marker found */ + { + rep0 = rep0_saved; + Rd_normalize( decoder->range_decoder ); + LZd_flush_data( decoder ); + if( len == min_match_len ) /* End Of Stream marker */ + { + if( LZd_verify_trailer( decoder, pp ) ) return 0; else return 3; + } + if( len == min_match_len + 1 ) /* Sync Flush marker */ + { + Rd_load( decoder->range_decoder ); continue; + } + if( pp->verbosity >= 0 ) + { + Pp_show_msg( pp, 0 ); + fprintf( stderr, "Unsupported marker code `%d'.\n", len ); + } + return 4; + } + } + } + rep3 = rep2; rep2 = rep1; rep1 = rep0_saved; + St_set_match( &state ); + if( rep0 >= (unsigned int)decoder->dictionary_size || + ( rep0 >= (unsigned int)decoder->pos && !decoder->partial_data_pos ) ) + { LZd_flush_data( decoder ); return 1; } + } + LZd_copy_block( decoder, rep0, len ); + } + } + } |