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-rw-r--r--decoder.c248
1 files changed, 248 insertions, 0 deletions
diff --git a/decoder.c b/decoder.c
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index 0000000..e6af722
--- /dev/null
+++ b/decoder.c
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+/* 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 );
+ }
+ }
+ }