summaryrefslogtreecommitdiffstats
path: root/decoder.cc
blob: 4c68355927cee1f7f80a3de88f5bd8656b7b63b7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
/* Lziprecover - Data recovery tool for the lzip format
   Copyright (C) 2009-2024 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 <algorithm>
#include <cerrno>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <string>
#include <vector>
#include <stdint.h>
#include <unistd.h>

#include "lzip.h"
#include "decoder.h"


const CRC32 crc32;


/* Return the number of bytes really read.
   If (value returned < size) and (errno == 0), means EOF was reached.
*/
long readblock( const int fd, uint8_t * const buf, const long size )
  {
  long sz = 0;
  errno = 0;
  while( sz < size )
    {
    const long 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.
*/
long writeblock( const int fd, const uint8_t * const buf, const long size )
  {
  long sz = 0;
  errno = 0;
  while( sz < size )
    {
    const long n = write( fd, buf + sz, size - sz );
    if( n > 0 ) sz += n;
    else if( n < 0 && errno != EINTR ) break;
    errno = 0;
    }
  return sz;
  }


bool Range_decoder::read_block()
  {
  if( !at_stream_end )
    {
    stream_pos = readblock( infd, buffer, buffer_size );
    if( stream_pos != buffer_size && errno ) throw Error( "Read error" );
    at_stream_end = ( stream_pos < buffer_size );
    partial_member_pos += pos;
    pos = 0;
    show_dprogress();
    }
  return pos < stream_pos;
  }


void LZ_decoder::flush_data()
  {
  if( pos > stream_pos )
    {
    const int size = pos - stream_pos;
    crc32.update_buf( crc_, buffer + stream_pos, size );
    if( outfd >= 0 )
      {
      const unsigned long long sp = stream_position();
      const long long i = positive_diff( outskip, sp );
      const long long s =
        std::min( positive_diff( outend, sp ), (unsigned long long)size ) - i;
      if( s > 0 && writeblock( outfd, buffer + stream_pos + i, s ) != s )
        throw Error( "Write error" );
      }
    if( pos >= dictionary_size )
      { partial_data_pos += pos; pos = 0; pos_wrapped = true; }
    stream_pos = pos;
    }
  }


int LZ_decoder::check_trailer( const Pretty_print & pp,
                               const bool ignore_empty ) const
  {
  Lzip_trailer trailer;
  int size = rdec.read_data( trailer.data, trailer.size );
  bool error = false;

  if( size < trailer.size )
    {
    error = true;
    if( verbosity >= 0 )
      { pp();
        std::fprintf( stderr, "Trailer truncated at trailer position %d;"
                              " some checks may fail.\n", size ); }
    while( size < trailer.size ) trailer.data[size++] = 0;
    }

  const unsigned td_crc = trailer.data_crc();
  if( td_crc != crc() )
    {
    error = true;
    if( verbosity >= 0 )
      { pp();
        std::fprintf( stderr, "CRC mismatch; stored %08X, computed %08X\n",
                      td_crc, crc() ); }
    }
  const unsigned long long data_size = data_position();
  const unsigned long long td_size = trailer.data_size();
  if( td_size != data_size )
    {
    error = true;
    if( verbosity >= 0 )
      { pp();
        std::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 member_size = rdec.member_position();
  const unsigned long long tm_size = trailer.member_size();
  if( tm_size != member_size )
    {
    error = true;
    if( verbosity >= 0 )
      { pp();
        std::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 3;
  if( !ignore_empty && data_size == 0 ) return 5;
  if( verbosity >= 2 )
    {
    if( verbosity >= 4 ) show_header( dictionary_size );
    if( data_size == 0 || member_size == 0 )
      std::fputs( "no data compressed. ", stderr );
    else
      std::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 ) std::fprintf( stderr, "CRC %08X, ", td_crc );
    if( verbosity >= 3 )
      std::fprintf( stderr, "%9llu out, %8llu in. ", data_size, member_size );
    }
  if( rdec.get_code() != 0 && verbosity >= 1 )
    {			// corruption in the last 4 bytes of the EOS marker
    pp();
    std::fprintf( stderr, "Range decoder final code is %08X\n", rdec.get_code() );
    }
  return 0;
  }


/* Return value: 0 = OK, 1 = decoder error, 2 = unexpected EOF,
                 3 = trailer error, 4 = unknown marker found,
                 5 = empty member found, 6 = marked member found. */
int LZ_decoder::decode_member( const Cl_options & cl_opts,
                               const Pretty_print & pp )
  {
  Bit_model bm_literal[1<<literal_context_bits][0x300];
  Bit_model bm_match[State::states][pos_states];
  Bit_model bm_rep[State::states];
  Bit_model bm_rep0[State::states];
  Bit_model bm_rep1[State::states];
  Bit_model bm_rep2[State::states];
  Bit_model bm_len[State::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];
  Len_model match_len_model;
  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;

  if( !rdec.load( cl_opts.ignore_marking ) ) return 6;
  while( !rdec.finished() )
    {
    const int pos_state = data_position() & pos_state_mask;
    if( rdec.decode_bit( bm_match[state()][pos_state] ) == 0 )	// 1st bit
      {
      // literal byte
      Bit_model * const bm = bm_literal[get_lit_state(peek_prev())];
      if( state.is_char_set_char() )
        put_byte( rdec.decode_tree8( bm ) );
      else
        put_byte( rdec.decode_matched( bm, peek( rep0 ) ) );
      continue;
      }
    // match or repeated match
    int len;
    if( rdec.decode_bit( bm_rep[state()] ) != 0 )		// 2nd bit
      {
      if( rdec.decode_bit( bm_rep0[state()] ) == 0 )		// 3rd bit
        {
        if( rdec.decode_bit( bm_len[state()][pos_state] ) == 0 ) // 4th bit
          { state.set_short_rep(); put_byte( peek( rep0 ) ); continue; }
        }
      else
        {
        unsigned distance;
        if( rdec.decode_bit( bm_rep1[state()] ) == 0 )		// 4th bit
          distance = rep1;
        else
          {
          if( rdec.decode_bit( bm_rep2[state()] ) == 0 )	// 5th bit
            distance = rep2;
          else
            { distance = rep3; rep3 = rep2; }
          rep2 = rep1;
          }
        rep1 = rep0;
        rep0 = distance;
        }
      state.set_rep();
      len = rdec.decode_len( rep_len_model, pos_state );
      }
    else					// match
      {
      len = rdec.decode_len( match_len_model, pos_state );
      unsigned distance = rdec.decode_tree6( 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 += rdec.decode_tree_reversed(
                      bm_dis + ( distance - dis_slot ), direct_bits );
        else
          {
          distance +=
            rdec.decode( direct_bits - dis_align_bits ) << dis_align_bits;
          distance += rdec.decode_tree_reversed4( bm_align );
          if( distance == 0xFFFFFFFFU )		// marker found
            {
            rdec.normalize();
            flush_data();
            if( len == min_match_len )		// End Of Stream marker
              return check_trailer( pp, cl_opts.ignore_empty );
            if( len == min_match_len + 1 )	// Sync Flush marker
              { rdec.load(); continue; }
            if( verbosity >= 0 )
              {
              pp();
              std::fprintf( stderr, "Unsupported marker code '%d'\n", len );
              }
            return 4;
            }
          }
        }
      rep3 = rep2; rep2 = rep1; rep1 = rep0; rep0 = distance;
      state.set_match();
      if( rep0 >= dictionary_size || ( rep0 >= pos && !pos_wrapped ) )
        { flush_data(); return 1; }
      }
    copy_block( rep0, len );
    }
  flush_data();
  return 2;
  }