util-linux/archival/lzo1x_d.c

   1 /* implementation of the LZO1X decompression algorithm
   2
   3    This file is part of the LZO real-time data compression library.
   4
   5    Copyright (C) 1996..2008 Markus Franz Xaver Johannes Oberhumer
   6    All Rights Reserved.
   7
   8    Markus F.X.J. Oberhumer <markus@oberhumer.com>
   9    http://www.oberhumer.com/opensource/lzo/
  10
  11    The LZO library is free software; you can redistribute it and/or
  12    modify it under the terms of the GNU General Public License as
  13    published by the Free Software Foundation; either version 2 of
  14    the License, or (at your option) any later version.
  15
  16    The LZO library is distributed in the hope that it will be useful,
  17    but WITHOUT ANY WARRANTY; without even the implied warranty of
  18    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19    GNU General Public License for more details.
  20
  21    You should have received a copy of the GNU General Public License
  22    along with the LZO library; see the file COPYING.
  23    If not, write to the Free Software Foundation, Inc.,
  24    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  25  */
  26 #include "libbb.h"
  27 #include "liblzo.h"
  28
  29 /***********************************************************************
  30 // decompress a block of data.
  31 ************************************************************************/
  32 /* safe decompression with overrun testing */
  33 int lzo1x_decompress_safe(const uint8_t* in, unsigned in_len,
  34                 uint8_t* out, unsigned* out_len,
  35                 void* wrkmem UNUSED_PARAM)
  36 {
  37         register uint8_t* op;
  38         register const uint8_t* ip;
  39         register unsigned t;
  40 #if defined(COPY_DICT)
  41         unsigned m_off;
  42         const uint8_t* dict_end;
  43 #else
  44         register const uint8_t* m_pos = NULL; /* possibly not needed */
  45 #endif
  46         const uint8_t* const ip_end = in + in_len;
  47 #if defined(HAVE_ANY_OP)
  48         uint8_t* const op_end = out + *out_len;
  49 #endif
  50 #if defined(LZO1Z)
  51         unsigned last_m_off = 0;
  52 #endif
  53
  54 //      LZO_UNUSED(wrkmem);
  55
  56 #if defined(COPY_DICT)
  57         if (dict) {
  58                 if (dict_len > M4_MAX_OFFSET) {
  59                         dict += dict_len - M4_MAX_OFFSET;
  60                         dict_len = M4_MAX_OFFSET;
  61                 }
  62                 dict_end = dict + dict_len;
  63         } else {
  64                 dict_len = 0;
  65                 dict_end = NULL;
  66         }
  67 #endif /* COPY_DICT */
  68
  69         *out_len = 0;
  70
  71         op = out;
  72         ip = in;
  73
  74         if (*ip > 17) {
  75                 t = *ip++ - 17;
  76                 if (t < 4)
  77                         goto match_next;
  78                 assert(t > 0); NEED_OP(t); NEED_IP(t+1);
  79                 do *op++ = *ip++; while (--t > 0);
  80                 goto first_literal_run;
  81         }
  82
  83         while (TEST_IP && TEST_OP) {
  84                 t = *ip++;
  85                 if (t >= 16)
  86                         goto match;
  87                 /* a literal run */
  88                 if (t == 0) {
  89                         NEED_IP(1);
  90                         while (*ip == 0) {
  91                                 t += 255;
  92                                 ip++;
  93                                 NEED_IP(1);
  94                         }
  95                         t += 15 + *ip++;
  96                 }
  97                 /* copy literals */
  98                 assert(t > 0);
  99                 NEED_OP(t+3);
 100                 NEED_IP(t+4);
 101 #if defined(LZO_UNALIGNED_OK_4) || defined(LZO_ALIGNED_OK_4)
 102 # if !defined(LZO_UNALIGNED_OK_4)
 103                 if (PTR_ALIGNED2_4(op, ip))
 104 # endif
 105                 {
 106                         COPY4(op, ip);
 107                         op += 4;
 108                         ip += 4;
 109                         if (--t > 0) {
 110                                 if (t >= 4) {
 111                                         do {
 112                                                 COPY4(op, ip);
 113                                                 op += 4;
 114                                                 ip += 4;
 115                                                 t -= 4;
 116                                         } while (t >= 4);
 117                                         if (t > 0)
 118                                                 do *op++ = *ip++; while (--t > 0);
 119                                 } else {
 120                                         do *op++ = *ip++; while (--t > 0);
 121                                 }
 122                         }
 123                 }
 124 # if !defined(LZO_UNALIGNED_OK_4)
 125                 else
 126 # endif
 127 #endif
 128 #if !defined(LZO_UNALIGNED_OK_4)
 129                 {
 130                         *op++ = *ip++;
 131                         *op++ = *ip++;
 132                         *op++ = *ip++;
 133                         do *op++ = *ip++; while (--t > 0);
 134                 }
 135 #endif
 136
 137  first_literal_run:
 138                 t = *ip++;
 139                 if (t >= 16)
 140                         goto match;
 141 #if defined(COPY_DICT)
 142 #if defined(LZO1Z)
 143                 m_off = (1 + M2_MAX_OFFSET) + (t << 6) + (*ip++ >> 2);
 144                 last_m_off = m_off;
 145 #else
 146                 m_off = (1 + M2_MAX_OFFSET) + (t >> 2) + (*ip++ << 2);
 147 #endif
 148                 NEED_OP(3);
 149                 t = 3; COPY_DICT(t,m_off)
 150 #else /* !COPY_DICT */
 151 #if defined(LZO1Z)
 152                 t = (1 + M2_MAX_OFFSET) + (t << 6) + (*ip++ >> 2);
 153                 m_pos = op - t;
 154                 last_m_off = t;
 155 #else
 156                 m_pos = op - (1 + M2_MAX_OFFSET);
 157                 m_pos -= t >> 2;
 158                 m_pos -= *ip++ << 2;
 159 #endif
 160                 TEST_LB(m_pos); NEED_OP(3);
 161                 *op++ = *m_pos++;
 162                 *op++ = *m_pos++;
 163                 *op++ = *m_pos;
 164 #endif /* COPY_DICT */
 165                 goto match_done;
 166
 167                 /* handle matches */
 168                 do {
 169  match:
 170                         if (t >= 64) {          /* a M2 match */
 171 #if defined(COPY_DICT)
 172 #if defined(LZO1X)
 173                                 m_off = 1 + ((t >> 2) & 7) + (*ip++ << 3);
 174                                 t = (t >> 5) - 1;
 175 #elif defined(LZO1Y)
 176                                 m_off = 1 + ((t >> 2) & 3) + (*ip++ << 2);
 177                                 t = (t >> 4) - 3;
 178 #elif defined(LZO1Z)
 179                                 m_off = t & 0x1f;
 180                                 if (m_off >= 0x1c)
 181                                         m_off = last_m_off;
 182                                 else {
 183                                         m_off = 1 + (m_off << 6) + (*ip++ >> 2);
 184                                         last_m_off = m_off;
 185                                 }
 186                                 t = (t >> 5) - 1;
 187 #endif
 188 #else /* !COPY_DICT */
 189 #if defined(LZO1X)
 190                                 m_pos = op - 1;
 191                                 m_pos -= (t >> 2) & 7;
 192                                 m_pos -= *ip++ << 3;
 193                                 t = (t >> 5) - 1;
 194 #elif defined(LZO1Y)
 195                                 m_pos = op - 1;
 196                                 m_pos -= (t >> 2) & 3;
 197                                 m_pos -= *ip++ << 2;
 198                                 t = (t >> 4) - 3;
 199 #elif defined(LZO1Z)
 200                                 {
 201                                         unsigned off = t & 0x1f;
 202                                         m_pos = op;
 203                                         if (off >= 0x1c) {
 204                                                 assert(last_m_off > 0);
 205                                                 m_pos -= last_m_off;
 206                                         } else {
 207                                                 off = 1 + (off << 6) + (*ip++ >> 2);
 208                                                 m_pos -= off;
 209                                                 last_m_off = off;
 210                                         }
 211                                 }
 212                                 t = (t >> 5) - 1;
 213 #endif
 214                                 TEST_LB(m_pos); assert(t > 0); NEED_OP(t+3-1);
 215                                 goto copy_match;
 216 #endif /* COPY_DICT */
 217                         }
 218                         else if (t >= 32) {                     /* a M3 match */
 219                                 t &= 31;
 220                                 if (t == 0) {
 221                                         NEED_IP(1);
 222                                         while (*ip == 0) {
 223                                                 t += 255;
 224                                                 ip++;
 225                                                 NEED_IP(1);
 226                                         }
 227                                         t += 31 + *ip++;
 228                                 }
 229 #if defined(COPY_DICT)
 230 #if defined(LZO1Z)
 231                                 m_off = 1 + (ip[0] << 6) + (ip[1] >> 2);
 232                                 last_m_off = m_off;
 233 #else
 234                                 m_off = 1 + (ip[0] >> 2) + (ip[1] << 6);
 235 #endif
 236 #else /* !COPY_DICT */
 237 #if defined(LZO1Z)
 238                                 {
 239                                         unsigned off = 1 + (ip[0] << 6) + (ip[1] >> 2);
 240                                         m_pos = op - off;
 241                                         last_m_off = off;
 242                                 }
 243 #elif defined(LZO_UNALIGNED_OK_2) && defined(LZO_ABI_LITTLE_ENDIAN)
 244                                 m_pos = op - 1;
 245                                 m_pos -= (* (const lzo_ushortp) ip) >> 2;
 246 #else
 247                                 m_pos = op - 1;
 248                                 m_pos -= (ip[0] >> 2) + (ip[1] << 6);
 249 #endif
 250 #endif /* COPY_DICT */
 251                                 ip += 2;
 252                         }
 253                         else if (t >= 16) {                     /* a M4 match */
 254 #if defined(COPY_DICT)
 255                                 m_off = (t & 8) << 11;
 256 #else /* !COPY_DICT */
 257                                 m_pos = op;
 258                                 m_pos -= (t & 8) << 11;
 259 #endif /* COPY_DICT */
 260                                 t &= 7;
 261                                 if (t == 0) {
 262                                         NEED_IP(1);
 263                                         while (*ip == 0) {
 264                                                 t += 255;
 265                                                 ip++;
 266                                                 NEED_IP(1);
 267                                         }
 268                                         t += 7 + *ip++;
 269                                 }
 270 #if defined(COPY_DICT)
 271 #if defined(LZO1Z)
 272                                 m_off += (ip[0] << 6) + (ip[1] >> 2);
 273 #else
 274                                 m_off += (ip[0] >> 2) + (ip[1] << 6);
 275 #endif
 276                                 ip += 2;
 277                                 if (m_off == 0)
 278                                         goto eof_found;
 279                                 m_off += 0x4000;
 280 #if defined(LZO1Z)
 281                                 last_m_off = m_off;
 282 #endif
 283 #else /* !COPY_DICT */
 284 #if defined(LZO1Z)
 285                                 m_pos -= (ip[0] << 6) + (ip[1] >> 2);
 286 #elif defined(LZO_UNALIGNED_OK_2) && defined(LZO_ABI_LITTLE_ENDIAN)
 287                                 m_pos -= (* (const lzo_ushortp) ip) >> 2;
 288 #else
 289                                 m_pos -= (ip[0] >> 2) + (ip[1] << 6);
 290 #endif
 291                                 ip += 2;
 292                                 if (m_pos == op)
 293                                         goto eof_found;
 294                                 m_pos -= 0x4000;
 295 #if defined(LZO1Z)
 296                                 last_m_off = pd((const uint8_t*)op, m_pos);
 297 #endif
 298 #endif /* COPY_DICT */
 299                         }
 300                         else {                          /* a M1 match */
 301 #if defined(COPY_DICT)
 302 #if defined(LZO1Z)
 303                                 m_off = 1 + (t << 6) + (*ip++ >> 2);
 304                                 last_m_off = m_off;
 305 #else
 306                                 m_off = 1 + (t >> 2) + (*ip++ << 2);
 307 #endif
 308                                 NEED_OP(2);
 309                                 t = 2; COPY_DICT(t,m_off)
 310 #else /* !COPY_DICT */
 311 #if defined(LZO1Z)
 312                                 t = 1 + (t << 6) + (*ip++ >> 2);
 313                                 m_pos = op - t;
 314                                 last_m_off = t;
 315 #else
 316                                 m_pos = op - 1;
 317                                 m_pos -= t >> 2;
 318                                 m_pos -= *ip++ << 2;
 319 #endif
 320                                 TEST_LB(m_pos); NEED_OP(2);
 321                                 *op++ = *m_pos++;
 322                                 *op++ = *m_pos;
 323 #endif /* COPY_DICT */
 324                                 goto match_done;
 325                         }
 326
 327                         /* copy match */
 328 #if defined(COPY_DICT)
 329
 330                         NEED_OP(t+3-1);
 331                         t += 3-1; COPY_DICT(t,m_off)
 332
 333 #else /* !COPY_DICT */
 334
 335                         TEST_LB(m_pos); assert(t > 0); NEED_OP(t+3-1);
 336 #if defined(LZO_UNALIGNED_OK_4) || defined(LZO_ALIGNED_OK_4)
 337 # if !defined(LZO_UNALIGNED_OK_4)
 338                         if (t >= 2 * 4 - (3 - 1) && PTR_ALIGNED2_4(op,m_pos)) {
 339                                 assert((op - m_pos) >= 4);      /* both pointers are aligned */
 340 # else
 341                         if (t >= 2 * 4 - (3 - 1) && (op - m_pos) >= 4) {
 342 # endif
 343                                 COPY4(op,m_pos);
 344                                 op += 4; m_pos += 4; t -= 4 - (3 - 1);
 345                                 do {
 346                                         COPY4(op,m_pos);
 347                                         op += 4; m_pos += 4; t -= 4;
 348                                 } while (t >= 4);
 349                                 if (t > 0)
 350                                         do *op++ = *m_pos++; while (--t > 0);
 351                         }
 352                         else
 353 #endif
 354                         {
 355  copy_match:
 356                                 *op++ = *m_pos++; *op++ = *m_pos++;
 357                                 do *op++ = *m_pos++; while (--t > 0);
 358                         }
 359
 360 #endif /* COPY_DICT */
 361
 362  match_done:
 363 #if defined(LZO1Z)
 364                         t = ip[-1] & 3;
 365 #else
 366                         t = ip[-2] & 3;
 367 #endif
 368                         if (t == 0)
 369                                 break;
 370
 371                         /* copy literals */
 372  match_next:
 373                         assert(t > 0);
 374                         assert(t < 4);
 375                         NEED_OP(t);
 376                         NEED_IP(t+1);
 377 #if 0
 378                         do *op++ = *ip++; while (--t > 0);
 379 #else
 380                         *op++ = *ip++;
 381                         if (t > 1) {
 382                                 *op++ = *ip++;
 383                                 if (t > 2)
 384                                         *op++ = *ip++;
 385                         }
 386 #endif
 387                         t = *ip++;
 388                 } while (TEST_IP && TEST_OP);
 389         }
 390
 391 //#if defined(HAVE_TEST_IP) || defined(HAVE_TEST_OP)
 392         /* no EOF code was found */
 393         *out_len = pd(op, out);
 394         return LZO_E_EOF_NOT_FOUND;
 395 //#endif
 396
 397  eof_found:
 398         assert(t == 1);
 399         *out_len = pd(op, out);
 400         return (ip == ip_end ? LZO_E_OK :
 401                    (ip < ip_end  ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN));
 402
 403 //#if defined(HAVE_NEED_IP)
 404  input_overrun:
 405         *out_len = pd(op, out);
 406         return LZO_E_INPUT_OVERRUN;
 407 //#endif
 408
 409 //#if defined(HAVE_NEED_OP)
 410  output_overrun:
 411         *out_len = pd(op, out);
 412         return LZO_E_OUTPUT_OVERRUN;
 413 //#endif
 414
 415 //#if defined(LZO_TEST_OVERRUN_LOOKBEHIND)
 416  lookbehind_overrun:
 417         *out_len = pd(op, out);
 418         return LZO_E_LOOKBEHIND_OVERRUN;
 419 //#endif
 420 }