bzdecompress.c (15185B)
1 /* 2 * THIS FILE IS NOT IDENTICAL TO THE ORIGINAL 3 * FROM THE BZIP2 DISTRIBUTION. 4 * 5 * It has been modified, mainly to break the library 6 * into smaller pieces. 7 * 8 * Russ Cox 9 * rsc@plan9.bell-labs.com 10 * July 2000 11 */ 12 13 /*-------------------------------------------------------------*/ 14 /*--- Library top-level functions. ---*/ 15 /*--- bzlib.c ---*/ 16 /*-------------------------------------------------------------*/ 17 18 /*-- 19 This file is a part of bzip2 and/or libbzip2, a program and 20 library for lossless, block-sorting data compression. 21 22 Copyright (C) 1996-2000 Julian R Seward. All rights reserved. 23 24 Redistribution and use in source and binary forms, with or without 25 modification, are permitted provided that the following conditions 26 are met: 27 28 1. Redistributions of source code must retain the above copyright 29 notice, this list of conditions and the following disclaimer. 30 31 2. The origin of this software must not be misrepresented; you must 32 not claim that you wrote the original software. If you use this 33 software in a product, an acknowledgment in the product 34 documentation would be appreciated but is not required. 35 36 3. Altered source versions must be plainly marked as such, and must 37 not be misrepresented as being the original software. 38 39 4. The name of the author may not be used to endorse or promote 40 products derived from this software without specific prior written 41 permission. 42 43 THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS 44 OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 45 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 46 ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY 47 DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 48 DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE 49 GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 50 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 51 WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 52 NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 53 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 54 55 Julian Seward, Cambridge, UK. 56 jseward@acm.org 57 bzip2/libbzip2 version 1.0 of 21 March 2000 58 59 This program is based on (at least) the work of: 60 Mike Burrows 61 David Wheeler 62 Peter Fenwick 63 Alistair Moffat 64 Radford Neal 65 Ian H. Witten 66 Robert Sedgewick 67 Jon L. Bentley 68 69 For more information on these sources, see the manual. 70 --*/ 71 72 /*-- 73 CHANGES 74 ~~~~~~~ 75 0.9.0 -- original version. 76 77 0.9.0a/b -- no changes in this file. 78 79 0.9.0c 80 * made zero-length BZ_FLUSH work correctly in bzCompress(). 81 * fixed bzWrite/bzRead to ignore zero-length requests. 82 * fixed bzread to correctly handle read requests after EOF. 83 * wrong parameter order in call to bzDecompressInit in 84 bzBuffToBuffDecompress. Fixed. 85 --*/ 86 87 #include "os.h" 88 #include "bzlib.h" 89 #include "bzlib_private.h" 90 91 /*---------------------------------------------------*/ 92 /*--- Decompression stuff ---*/ 93 /*---------------------------------------------------*/ 94 95 /*---------------------------------------------------*/ 96 int BZ_API(BZ2_bzDecompressInit) 97 ( bz_stream* strm, 98 int verbosity, 99 int small ) 100 { 101 DState* s; 102 103 if (!bz_config_ok()) return BZ_CONFIG_ERROR; 104 105 if (strm == NULL) return BZ_PARAM_ERROR; 106 if (small != 0 && small != 1) return BZ_PARAM_ERROR; 107 if (verbosity < 0 || verbosity > 4) return BZ_PARAM_ERROR; 108 109 if (strm->bzalloc == NULL) strm->bzalloc = default_bzalloc; 110 if (strm->bzfree == NULL) strm->bzfree = default_bzfree; 111 112 s = BZALLOC( sizeof(DState) ); 113 if (s == NULL) return BZ_MEM_ERROR; 114 s->strm = strm; 115 strm->state = s; 116 s->state = BZ_X_MAGIC_1; 117 s->bsLive = 0; 118 s->bsBuff = 0; 119 s->calculatedCombinedCRC = 0; 120 strm->total_in_lo32 = 0; 121 strm->total_in_hi32 = 0; 122 strm->total_out_lo32 = 0; 123 strm->total_out_hi32 = 0; 124 s->smallDecompress = (Bool)small; 125 s->ll4 = NULL; 126 s->ll16 = NULL; 127 s->tt = NULL; 128 s->currBlockNo = 0; 129 s->verbosity = verbosity; 130 131 return BZ_OK; 132 } 133 134 135 /*---------------------------------------------------*/ 136 static 137 void unRLE_obuf_to_output_FAST ( DState* s ) 138 { 139 UChar k1; 140 141 if (s->blockRandomised) { 142 143 while (True) { 144 /* try to finish existing run */ 145 while (True) { 146 if (s->strm->avail_out == 0) return; 147 if (s->state_out_len == 0) break; 148 *( (UChar*)(s->strm->next_out) ) = s->state_out_ch; 149 BZ_UPDATE_CRC ( s->calculatedBlockCRC, s->state_out_ch ); 150 s->state_out_len--; 151 s->strm->next_out++; 152 s->strm->avail_out--; 153 s->strm->total_out_lo32++; 154 if (s->strm->total_out_lo32 == 0) s->strm->total_out_hi32++; 155 } 156 157 /* can a new run be started? */ 158 if (s->nblock_used == s->save_nblock+1) return; 159 160 161 s->state_out_len = 1; 162 s->state_out_ch = s->k0; 163 BZ_GET_FAST(k1); BZ_RAND_UPD_MASK; 164 k1 ^= BZ_RAND_MASK; s->nblock_used++; 165 if (s->nblock_used == s->save_nblock+1) continue; 166 if (k1 != s->k0) { s->k0 = k1; continue; }; 167 168 s->state_out_len = 2; 169 BZ_GET_FAST(k1); BZ_RAND_UPD_MASK; 170 k1 ^= BZ_RAND_MASK; s->nblock_used++; 171 if (s->nblock_used == s->save_nblock+1) continue; 172 if (k1 != s->k0) { s->k0 = k1; continue; }; 173 174 s->state_out_len = 3; 175 BZ_GET_FAST(k1); BZ_RAND_UPD_MASK; 176 k1 ^= BZ_RAND_MASK; s->nblock_used++; 177 if (s->nblock_used == s->save_nblock+1) continue; 178 if (k1 != s->k0) { s->k0 = k1; continue; }; 179 180 BZ_GET_FAST(k1); BZ_RAND_UPD_MASK; 181 k1 ^= BZ_RAND_MASK; s->nblock_used++; 182 s->state_out_len = ((Int32)k1) + 4; 183 BZ_GET_FAST(s->k0); BZ_RAND_UPD_MASK; 184 s->k0 ^= BZ_RAND_MASK; s->nblock_used++; 185 } 186 187 } else { 188 189 /* restore */ 190 UInt32 c_calculatedBlockCRC = s->calculatedBlockCRC; 191 UChar c_state_out_ch = s->state_out_ch; 192 Int32 c_state_out_len = s->state_out_len; 193 Int32 c_nblock_used = s->nblock_used; 194 Int32 c_k0 = s->k0; 195 UInt32* c_tt = s->tt; 196 UInt32 c_tPos = s->tPos; 197 char* cs_next_out = s->strm->next_out; 198 unsigned int cs_avail_out = s->strm->avail_out; 199 /* end restore */ 200 201 UInt32 avail_out_INIT = cs_avail_out; 202 Int32 s_save_nblockPP = s->save_nblock+1; 203 unsigned int total_out_lo32_old; 204 205 while (True) { 206 207 /* try to finish existing run */ 208 if (c_state_out_len > 0) { 209 while (True) { 210 if (cs_avail_out == 0) goto return_notr; 211 if (c_state_out_len == 1) break; 212 *( (UChar*)(cs_next_out) ) = c_state_out_ch; 213 BZ_UPDATE_CRC ( c_calculatedBlockCRC, c_state_out_ch ); 214 c_state_out_len--; 215 cs_next_out++; 216 cs_avail_out--; 217 } 218 s_state_out_len_eq_one: 219 { 220 if (cs_avail_out == 0) { 221 c_state_out_len = 1; goto return_notr; 222 }; 223 *( (UChar*)(cs_next_out) ) = c_state_out_ch; 224 BZ_UPDATE_CRC ( c_calculatedBlockCRC, c_state_out_ch ); 225 cs_next_out++; 226 cs_avail_out--; 227 } 228 } 229 /* can a new run be started? */ 230 if (c_nblock_used == s_save_nblockPP) { 231 c_state_out_len = 0; goto return_notr; 232 }; 233 c_state_out_ch = c_k0; 234 BZ_GET_FAST_C(k1); c_nblock_used++; 235 if (k1 != c_k0) { 236 c_k0 = k1; goto s_state_out_len_eq_one; 237 }; 238 if (c_nblock_used == s_save_nblockPP) 239 goto s_state_out_len_eq_one; 240 241 c_state_out_len = 2; 242 BZ_GET_FAST_C(k1); c_nblock_used++; 243 if (c_nblock_used == s_save_nblockPP) continue; 244 if (k1 != c_k0) { c_k0 = k1; continue; }; 245 246 c_state_out_len = 3; 247 BZ_GET_FAST_C(k1); c_nblock_used++; 248 if (c_nblock_used == s_save_nblockPP) continue; 249 if (k1 != c_k0) { c_k0 = k1; continue; }; 250 251 BZ_GET_FAST_C(k1); c_nblock_used++; 252 c_state_out_len = ((Int32)k1) + 4; 253 BZ_GET_FAST_C(c_k0); c_nblock_used++; 254 } 255 256 return_notr: 257 total_out_lo32_old = s->strm->total_out_lo32; 258 s->strm->total_out_lo32 += (avail_out_INIT - cs_avail_out); 259 if (s->strm->total_out_lo32 < total_out_lo32_old) 260 s->strm->total_out_hi32++; 261 262 /* save */ 263 s->calculatedBlockCRC = c_calculatedBlockCRC; 264 s->state_out_ch = c_state_out_ch; 265 s->state_out_len = c_state_out_len; 266 s->nblock_used = c_nblock_used; 267 s->k0 = c_k0; 268 s->tt = c_tt; 269 s->tPos = c_tPos; 270 s->strm->next_out = cs_next_out; 271 s->strm->avail_out = cs_avail_out; 272 /* end save */ 273 } 274 } 275 276 277 278 /*---------------------------------------------------*/ 279 __inline__ Int32 BZ2_indexIntoF ( Int32 indx, Int32 *cftab ) 280 { 281 Int32 nb, na, mid; 282 nb = 0; 283 na = 256; 284 do { 285 mid = (nb + na) >> 1; 286 if (indx >= cftab[mid]) nb = mid; else na = mid; 287 } 288 while (na - nb != 1); 289 return nb; 290 } 291 292 293 /*---------------------------------------------------*/ 294 static 295 void unRLE_obuf_to_output_SMALL ( DState* s ) 296 { 297 UChar k1; 298 299 if (s->blockRandomised) { 300 301 while (True) { 302 /* try to finish existing run */ 303 while (True) { 304 if (s->strm->avail_out == 0) return; 305 if (s->state_out_len == 0) break; 306 *( (UChar*)(s->strm->next_out) ) = s->state_out_ch; 307 BZ_UPDATE_CRC ( s->calculatedBlockCRC, s->state_out_ch ); 308 s->state_out_len--; 309 s->strm->next_out++; 310 s->strm->avail_out--; 311 s->strm->total_out_lo32++; 312 if (s->strm->total_out_lo32 == 0) s->strm->total_out_hi32++; 313 } 314 315 /* can a new run be started? */ 316 if (s->nblock_used == s->save_nblock+1) return; 317 318 319 s->state_out_len = 1; 320 s->state_out_ch = s->k0; 321 BZ_GET_SMALL(k1); BZ_RAND_UPD_MASK; 322 k1 ^= BZ_RAND_MASK; s->nblock_used++; 323 if (s->nblock_used == s->save_nblock+1) continue; 324 if (k1 != s->k0) { s->k0 = k1; continue; }; 325 326 s->state_out_len = 2; 327 BZ_GET_SMALL(k1); BZ_RAND_UPD_MASK; 328 k1 ^= BZ_RAND_MASK; s->nblock_used++; 329 if (s->nblock_used == s->save_nblock+1) continue; 330 if (k1 != s->k0) { s->k0 = k1; continue; }; 331 332 s->state_out_len = 3; 333 BZ_GET_SMALL(k1); BZ_RAND_UPD_MASK; 334 k1 ^= BZ_RAND_MASK; s->nblock_used++; 335 if (s->nblock_used == s->save_nblock+1) continue; 336 if (k1 != s->k0) { s->k0 = k1; continue; }; 337 338 BZ_GET_SMALL(k1); BZ_RAND_UPD_MASK; 339 k1 ^= BZ_RAND_MASK; s->nblock_used++; 340 s->state_out_len = ((Int32)k1) + 4; 341 BZ_GET_SMALL(s->k0); BZ_RAND_UPD_MASK; 342 s->k0 ^= BZ_RAND_MASK; s->nblock_used++; 343 } 344 345 } else { 346 347 while (True) { 348 /* try to finish existing run */ 349 while (True) { 350 if (s->strm->avail_out == 0) return; 351 if (s->state_out_len == 0) break; 352 *( (UChar*)(s->strm->next_out) ) = s->state_out_ch; 353 BZ_UPDATE_CRC ( s->calculatedBlockCRC, s->state_out_ch ); 354 s->state_out_len--; 355 s->strm->next_out++; 356 s->strm->avail_out--; 357 s->strm->total_out_lo32++; 358 if (s->strm->total_out_lo32 == 0) s->strm->total_out_hi32++; 359 } 360 361 /* can a new run be started? */ 362 if (s->nblock_used == s->save_nblock+1) return; 363 364 s->state_out_len = 1; 365 s->state_out_ch = s->k0; 366 BZ_GET_SMALL(k1); s->nblock_used++; 367 if (s->nblock_used == s->save_nblock+1) continue; 368 if (k1 != s->k0) { s->k0 = k1; continue; }; 369 370 s->state_out_len = 2; 371 BZ_GET_SMALL(k1); s->nblock_used++; 372 if (s->nblock_used == s->save_nblock+1) continue; 373 if (k1 != s->k0) { s->k0 = k1; continue; }; 374 375 s->state_out_len = 3; 376 BZ_GET_SMALL(k1); s->nblock_used++; 377 if (s->nblock_used == s->save_nblock+1) continue; 378 if (k1 != s->k0) { s->k0 = k1; continue; }; 379 380 BZ_GET_SMALL(k1); s->nblock_used++; 381 s->state_out_len = ((Int32)k1) + 4; 382 BZ_GET_SMALL(s->k0); s->nblock_used++; 383 } 384 385 } 386 } 387 388 389 /*---------------------------------------------------*/ 390 int BZ_API(BZ2_bzDecompress) ( bz_stream *strm ) 391 { 392 DState* s; 393 if (strm == NULL) return BZ_PARAM_ERROR; 394 s = strm->state; 395 if (s == NULL) return BZ_PARAM_ERROR; 396 if (s->strm != strm) return BZ_PARAM_ERROR; 397 398 while (True) { 399 if (s->state == BZ_X_IDLE) return BZ_SEQUENCE_ERROR; 400 if (s->state == BZ_X_OUTPUT) { 401 if (s->smallDecompress) 402 unRLE_obuf_to_output_SMALL ( s ); else 403 unRLE_obuf_to_output_FAST ( s ); 404 if (s->nblock_used == s->save_nblock+1 && s->state_out_len == 0) { 405 BZ_FINALISE_CRC ( s->calculatedBlockCRC ); 406 if (s->verbosity >= 3) 407 VPrintf2 ( " {0x%x, 0x%x}", s->storedBlockCRC, 408 s->calculatedBlockCRC ); 409 if (s->verbosity >= 2) VPrintf0 ( "]" ); 410 if (s->calculatedBlockCRC != s->storedBlockCRC) 411 return BZ_DATA_ERROR; 412 s->calculatedCombinedCRC 413 = (s->calculatedCombinedCRC << 1) | 414 (s->calculatedCombinedCRC >> 31); 415 s->calculatedCombinedCRC ^= s->calculatedBlockCRC; 416 s->state = BZ_X_BLKHDR_1; 417 } else { 418 return BZ_OK; 419 } 420 } 421 if (s->state >= BZ_X_MAGIC_1) { 422 Int32 r = BZ2_decompress ( s ); 423 if (r == BZ_STREAM_END) { 424 if (s->verbosity >= 3) 425 VPrintf2 ( "\n combined CRCs: stored = 0x%x, computed = 0x%x", 426 s->storedCombinedCRC, s->calculatedCombinedCRC ); 427 if (s->calculatedCombinedCRC != s->storedCombinedCRC) 428 return BZ_DATA_ERROR; 429 return r; 430 } 431 if (s->state != BZ_X_OUTPUT) return r; 432 } 433 } 434 435 /* 436 AssertH ( 0, 6001 ); 437 438 return 0; 439 */ 440 } 441 442 443 /*---------------------------------------------------*/ 444 int BZ_API(BZ2_bzDecompressEnd) ( bz_stream *strm ) 445 { 446 DState* s; 447 if (strm == NULL) return BZ_PARAM_ERROR; 448 s = strm->state; 449 if (s == NULL) return BZ_PARAM_ERROR; 450 if (s->strm != strm) return BZ_PARAM_ERROR; 451 452 if (s->tt != NULL) BZFREE(s->tt); 453 if (s->ll16 != NULL) BZFREE(s->ll16); 454 if (s->ll4 != NULL) BZFREE(s->ll4); 455 456 BZFREE(strm->state); 457 strm->state = NULL; 458 459 return BZ_OK; 460 }