diff options
Diffstat (limited to 'decoder.c')
| -rw-r--r-- | decoder.c | 317 |
1 files changed, 317 insertions, 0 deletions
diff --git a/decoder.c b/decoder.c new file mode 100644 index 0000000..b52b35f --- /dev/null +++ b/decoder.c @@ -0,0 +1,317 @@ +/* Lunzip - Decompressor for the lzip format + Copyright (C) 2010-2022 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 2 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 <unistd.h> + +#include "lzip.h" +#include "decoder.h" + + +CRC32 crc32; + + +/* Return the number of bytes really read. + If (value returned < size) and (errno == 0), means EOF was reached. +*/ +int readblock( const int fd, uint8_t * const buf, const int size ) + { + int sz = 0; + errno = 0; + while( sz < size ) + { + const int n = read( fd, buf + sz, size - sz ); + if( n > 0 ) sz += n; + else if( n == 0 ) break; /* EOF */ + else if( errno != EINTR ) break; + errno = 0; + } + return sz; + } + + +/* Return the number of bytes really written. + If (value returned < size), it is always an error. +*/ +static int writeblock( const int fd, const uint8_t * const buf, const int size ) + { + int sz = 0; + errno = 0; + while( sz < size ) + { + const int n = write( fd, buf + sz, size - sz ); + if( n > 0 ) sz += n; + else if( n < 0 && errno != EINTR ) break; + errno = 0; + } + return sz; + } + + +unsigned seek_read_back( const int fd, uint8_t * const buf, const int size, + const int offset ) + { + if( lseek( fd, -offset, SEEK_END ) >= 0 ) + return readblock( fd, buf, size ); + return 0; + } + + +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; + show_dprogress( 0, 0, 0, 0 ); + } + return rdec->pos < rdec->stream_pos; + } + + +void LZd_flush_data( struct LZ_decoder * const d ) + { + if( d->pos > d->stream_pos ) + { + const int size = d->pos - d->stream_pos; + CRC32_update_buf( &d->crc, d->buffer + d->stream_pos, size ); + if( d->outfd >= 0 && + writeblock( d->outfd, d->buffer + d->stream_pos, size ) != size ) + { show_error( "Write error", errno, false ); cleanup_and_fail( 1 ); } + if( d->pos >= d->buffer_size ) + { d->partial_data_pos += d->pos; d->pos = 0; + if( d->partial_data_pos >= d->dictionary_size ) d->pos_wrapped = true; } + d->stream_pos = d->pos; + } + } + + +static bool LZd_verify_trailer( struct LZ_decoder * const d, + struct Pretty_print * const pp ) + { + Lzip_trailer trailer; + int size = Rd_read_data( d->rdec, trailer, Lt_size ); + const unsigned long long data_size = LZd_data_position( d ); + const unsigned long long member_size = Rd_member_position( d->rdec ); + bool error = false; + + if( size < Lt_size ) + { + error = true; + if( verbosity >= 0 ) + { + Pp_show_msg( pp, 0 ); + fprintf( stderr, "Trailer truncated at trailer position %d;" + " some checks may fail.\n", size ); + } + while( size < Lt_size ) trailer[size++] = 0; + } + + const unsigned td_crc = Lt_get_data_crc( trailer ); + if( td_crc != LZd_crc( d ) ) + { + error = true; + if( verbosity >= 0 ) + { + Pp_show_msg( pp, 0 ); + fprintf( stderr, "CRC mismatch; stored %08X, computed %08X\n", + td_crc, LZd_crc( d ) ); + } + } + const unsigned long long td_size = Lt_get_data_size( trailer ); + if( td_size != data_size ) + { + error = true; + if( verbosity >= 0 ) + { + Pp_show_msg( pp, 0 ); + fprintf( stderr, "Data size mismatch; stored %llu (0x%llX), computed %llu (0x%llX)\n", + td_size, td_size, data_size, data_size ); + } + } + const unsigned long long tm_size = Lt_get_member_size( trailer ); + if( tm_size != member_size ) + { + error = true; + if( verbosity >= 0 ) + { + Pp_show_msg( pp, 0 ); + fprintf( stderr, "Member size mismatch; stored %llu (0x%llX), computed %llu (0x%llX)\n", + tm_size, tm_size, member_size, member_size ); + } + } + if( error ) return false; + if( verbosity >= 2 ) + { + if( verbosity >= 4 ) show_header( d->dictionary_size ); + if( data_size == 0 || member_size == 0 ) + fputs( "no data compressed. ", stderr ); + else + fprintf( stderr, "%6.3f:1, %5.2f%% ratio, %5.2f%% saved. ", + (double)data_size / member_size, + ( 100.0 * member_size ) / data_size, + 100.0 - ( ( 100.0 * member_size ) / data_size ) ); + if( verbosity >= 4 ) fprintf( stderr, "CRC %08X, ", td_crc ); + if( verbosity >= 3 ) + fprintf( stderr, "%9llu out, %8llu in. ", data_size, member_size ); + } + return true; + } + + +/* 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 d, + struct Pretty_print * const pp ) + { + struct Range_decoder * const rdec = d->rdec; + Bit_model bm_literal[1<<literal_context_bits][0x300]; + Bit_model bm_match[states][pos_states]; + Bit_model bm_rep[states]; + Bit_model bm_rep0[states]; + Bit_model bm_rep1[states]; + 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+1]; + Bit_model bm_align[dis_align_size]; + struct Len_model match_len_model; + struct Len_model rep_len_model; + unsigned rep0 = 0; /* rep[0-3] latest four distances */ + unsigned rep1 = 0; /* used for efficient coding of */ + unsigned rep2 = 0; /* repeated distances */ + unsigned rep3 = 0; + State state = 0; + const bool full_buffer = d->buffer_size >= d->dictionary_size; + + Bm_array_init( bm_literal[0], (1 << literal_context_bits) * 0x300 ); + Bm_array_init( bm_match[0], states * pos_states ); + Bm_array_init( bm_rep, states ); + Bm_array_init( bm_rep0, states ); + Bm_array_init( bm_rep1, states ); + Bm_array_init( bm_rep2, states ); + Bm_array_init( bm_len[0], states * pos_states ); + Bm_array_init( bm_dis_slot[0], len_states * (1 << dis_slot_bits) ); + Bm_array_init( bm_dis, modeled_distances - end_dis_model + 1 ); + Bm_array_init( bm_align, dis_align_size ); + Lm_init( &match_len_model ); + Lm_init( &rep_len_model ); + + Rd_load( rdec ); + while( !Rd_finished( rdec ) ) + { + const int pos_state = LZd_data_position( d ) & pos_state_mask; + if( Rd_decode_bit( rdec, &bm_match[state][pos_state] ) == 0 ) /* 1st bit */ + { + /* literal byte */ + Bit_model * const bm = bm_literal[get_lit_state(LZd_peek_prev( d ))]; + if( ( state = St_set_char( state ) ) < 4 ) + LZd_put_byte( d, Rd_decode_tree8( rdec, bm ) ); + else + LZd_put_byte( d, Rd_decode_matched( rdec, bm, LZd_peek( d, rep0 ) ) ); + continue; + } + /* match or repeated match */ + int len; + if( Rd_decode_bit( rdec, &bm_rep[state] ) != 0 ) /* 2nd bit */ + { + if( Rd_decode_bit( rdec, &bm_rep0[state] ) == 0 ) /* 3rd bit */ + { + if( Rd_decode_bit( rdec, &bm_len[state][pos_state] ) == 0 ) /* 4th bit */ + { state = St_set_short_rep( state ); + LZd_put_byte( d, LZd_peek( d, rep0 ) ); continue; } + } + else + { + unsigned distance; + if( Rd_decode_bit( rdec, &bm_rep1[state] ) == 0 ) /* 4th bit */ + distance = rep1; + else + { + if( Rd_decode_bit( rdec, &bm_rep2[state] ) == 0 ) /* 5th bit */ + distance = rep2; + else + { distance = rep3; rep3 = rep2; } + rep2 = rep1; + } + rep1 = rep0; + rep0 = distance; + } + state = St_set_rep( state ); + len = Rd_decode_len( rdec, &rep_len_model, pos_state ); + } + else /* match */ + { + len = Rd_decode_len( rdec, &match_len_model, pos_state ); + unsigned distance = Rd_decode_tree6( rdec, 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, + 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, bm_align ); + if( distance == 0xFFFFFFFFU ) /* marker found */ + { + Rd_normalize( rdec ); + LZd_flush_data( d ); + if( len == min_match_len ) /* End Of Stream marker */ + { + if( LZd_verify_trailer( d, pp ) ) return 0; else return 3; + } + if( len == min_match_len + 1 ) /* Sync Flush marker */ + { + Rd_load( rdec ); continue; + } + if( verbosity >= 0 ) + { + Pp_show_msg( pp, 0 ); + fprintf( stderr, "Unsupported marker code '%d'\n", len ); + } + return 4; + } + } + } + rep3 = rep2; rep2 = rep1; rep1 = rep0; rep0 = distance; + state = St_set_match( state ); + if( rep0 >= d->dictionary_size || + ( !d->pos_wrapped && rep0 >= LZd_data_position( d ) ) ) + { LZd_flush_data( d ); return 1; } + } + if( full_buffer || rep0 < d->buffer_size ) LZd_copy_block( d, rep0, len ); + else LZd_copy_block2( d, rep0, len ); + } + LZd_flush_data( d ); + return 2; + } |