1 2 /*-------------------------------------------------------------*/ 3 /*--- Compression machinery (not incl block sorting) ---*/ 4 /*--- compress.c ---*/ 5 /*-------------------------------------------------------------*/ 6 7 /* ------------------------------------------------------------------ 8 This file is part of bzip2/libbzip2, a program and library for 9 lossless, block-sorting data compression. 10 11 bzip2/libbzip2 version 1.0.4 of 20 December 2006 12 Copyright (C) 1996-2006 Julian Seward <jseward@bzip.org> 13 14 Please read the WARNING, DISCLAIMER and PATENTS sections in the 15 README file. 16 17 This program is released under the terms of the license contained 18 in the file LICENSE. 19 ------------------------------------------------------------------ */ 20 21 22 /* CHANGES 23 0.9.0 -- original version. 24 0.9.0a/b -- no changes in this file. 25 0.9.0c -- changed setting of nGroups in sendMTFValues() 26 so as to do a bit better on small files 27 */ 28 29 #include "bzlib_private.h" 30 31 32 /*---------------------------------------------------*/ 33 /*--- Bit stream I/O ---*/ 34 /*---------------------------------------------------*/ 35 36 /*---------------------------------------------------*/ 37 void BZ2_bsInitWrite ( EState* s ) 38 { 39 s->bsLive = 0; 40 s->bsBuff = 0; 41 } 42 43 44 /*---------------------------------------------------*/ 45 static 46 void bsFinishWrite ( EState* s ) 47 { 48 while (s->bsLive > 0) { 49 s->zbits[s->numZ] = (UChar)(s->bsBuff >> 24); 50 s->numZ++; 51 s->bsBuff <<= 8; 52 s->bsLive -= 8; 53 } 54 } 55 56 57 /*---------------------------------------------------*/ 58 #define bsNEEDW(nz) \ 59 { \ 60 while (s->bsLive >= 8) { \ 61 s->zbits[s->numZ] \ 62 = (UChar)(s->bsBuff >> 24); \ 63 s->numZ++; \ 64 s->bsBuff <<= 8; \ 65 s->bsLive -= 8; \ 66 } \ 67 } 68 69 70 /*---------------------------------------------------*/ 71 static 72 __inline__ 73 void bsW ( EState* s, Int32 n, UInt32 v ) 74 { 75 bsNEEDW ( n ); 76 s->bsBuff |= (v << (32 - s->bsLive - n)); 77 s->bsLive += n; 78 } 79 80 81 /*---------------------------------------------------*/ 82 static 83 void bsPutUInt32 ( EState* s, UInt32 u ) 84 { 85 bsW ( s, 8, (u >> 24) & 0xffL ); 86 bsW ( s, 8, (u >> 16) & 0xffL ); 87 bsW ( s, 8, (u >> 8) & 0xffL ); 88 bsW ( s, 8, u & 0xffL ); 89 } 90 91 92 /*---------------------------------------------------*/ 93 static 94 void bsPutUChar ( EState* s, UChar c ) 95 { 96 bsW( s, 8, (UInt32)c ); 97 } 98 99 100 /*---------------------------------------------------*/ 101 /*--- The back end proper ---*/ 102 /*---------------------------------------------------*/ 103 104 /*---------------------------------------------------*/ 105 static 106 void makeMaps_e ( EState* s ) 107 { 108 Int32 i; 109 s->nInUse = 0; 110 for (i = 0; i < 256; i++) 111 if (s->inUse[i]) { 112 s->unseqToSeq[i] = s->nInUse; 113 s->nInUse++; 114 } 115 } 116 117 118 /*---------------------------------------------------*/ 119 static 120 void generateMTFValues ( EState* s ) 121 { 122 UChar yy[256]; 123 Int32 i, j; 124 Int32 zPend; 125 Int32 wr; 126 Int32 EOB; 127 128 /* 129 After sorting (eg, here), 130 s->arr1 [ 0 .. s->nblock-1 ] holds sorted order, 131 and 132 ((UChar*)s->arr2) [ 0 .. s->nblock-1 ] 133 holds the original block data. 134 135 The first thing to do is generate the MTF values, 136 and put them in 137 ((UInt16*)s->arr1) [ 0 .. s->nblock-1 ]. 138 Because there are strictly fewer or equal MTF values 139 than block values, ptr values in this area are overwritten 140 with MTF values only when they are no longer needed. 141 142 The final compressed bitstream is generated into the 143 area starting at 144 (UChar*) (&((UChar*)s->arr2)[s->nblock]) 145 146 These storage aliases are set up in bzCompressInit(), 147 except for the last one, which is arranged in 148 compressBlock(). 149 */ 150 UInt32* ptr = s->ptr; 151 UChar* block = s->block; 152 UInt16* mtfv = s->mtfv; 153 154 makeMaps_e ( s ); 155 EOB = s->nInUse+1; 156 157 for (i = 0; i <= EOB; i++) s->mtfFreq[i] = 0; 158 159 wr = 0; 160 zPend = 0; 161 for (i = 0; i < s->nInUse; i++) yy[i] = (UChar) i; 162 163 for (i = 0; i < s->nblock; i++) { 164 UChar ll_i; 165 AssertD ( wr <= i, "generateMTFValues(1)" ); 166 j = ptr[i]-1; if (j < 0) j += s->nblock; 167 ll_i = s->unseqToSeq[block[j]]; 168 AssertD ( ll_i < s->nInUse, "generateMTFValues(2a)" ); 169 170 if (yy[0] == ll_i) { 171 zPend++; 172 } else { 173 174 if (zPend > 0) { 175 zPend--; 176 while (True) { 177 if (zPend & 1) { 178 mtfv[wr] = BZ_RUNB; wr++; 179 s->mtfFreq[BZ_RUNB]++; 180 } else { 181 mtfv[wr] = BZ_RUNA; wr++; 182 s->mtfFreq[BZ_RUNA]++; 183 } 184 if (zPend < 2) break; 185 zPend = (zPend - 2) / 2; 186 }; 187 zPend = 0; 188 } 189 { 190 register UChar rtmp; 191 register UChar* ryy_j; 192 register UChar rll_i; 193 rtmp = yy[1]; 194 yy[1] = yy[0]; 195 ryy_j = &(yy[1]); 196 rll_i = ll_i; 197 while ( rll_i != rtmp ) { 198 register UChar rtmp2; 199 ryy_j++; 200 rtmp2 = rtmp; 201 rtmp = *ryy_j; 202 *ryy_j = rtmp2; 203 }; 204 yy[0] = rtmp; 205 j = ryy_j - &(yy[0]); 206 mtfv[wr] = j+1; wr++; s->mtfFreq[j+1]++; 207 } 208 209 } 210 } 211 212 if (zPend > 0) { 213 zPend--; 214 while (True) { 215 if (zPend & 1) { 216 mtfv[wr] = BZ_RUNB; wr++; 217 s->mtfFreq[BZ_RUNB]++; 218 } else { 219 mtfv[wr] = BZ_RUNA; wr++; 220 s->mtfFreq[BZ_RUNA]++; 221 } 222 if (zPend < 2) break; 223 zPend = (zPend - 2) / 2; 224 }; 225 zPend = 0; 226 } 227 228 mtfv[wr] = EOB; wr++; s->mtfFreq[EOB]++; 229 230 s->nMTF = wr; 231 } 232 233 234 /*---------------------------------------------------*/ 235 #define BZ_LESSER_ICOST 0 236 #define BZ_GREATER_ICOST 15 237 238 static 239 void sendMTFValues ( EState* s ) 240 { 241 Int32 v, t, i, j, gs, ge, totc, bt, bc, iter; 242 Int32 nSelectors, alphaSize, minLen, maxLen, selCtr; 243 Int32 nGroups, nBytes; 244 245 /*-- 246 UChar len [BZ_N_GROUPS][BZ_MAX_ALPHA_SIZE]; 247 is a global since the decoder also needs it. 248 249 Int32 code[BZ_N_GROUPS][BZ_MAX_ALPHA_SIZE]; 250 Int32 rfreq[BZ_N_GROUPS][BZ_MAX_ALPHA_SIZE]; 251 are also globals only used in this proc. 252 Made global to keep stack frame size small. 253 --*/ 254 255 256 UInt16 cost[BZ_N_GROUPS]; 257 Int32 fave[BZ_N_GROUPS]; 258 259 UInt16* mtfv = s->mtfv; 260 261 if (s->verbosity >= 3) 262 VPrintf3( " %d in block, %d after MTF & 1-2 coding, " 263 "%d+2 syms in use\n", 264 s->nblock, s->nMTF, s->nInUse ); 265 266 alphaSize = s->nInUse+2; 267 for (t = 0; t < BZ_N_GROUPS; t++) 268 for (v = 0; v < alphaSize; v++) 269 s->len[t][v] = BZ_GREATER_ICOST; 270 271 /*--- Decide how many coding tables to use ---*/ 272 AssertH ( s->nMTF > 0, 3001 ); 273 if (s->nMTF < 200) nGroups = 2; else 274 if (s->nMTF < 600) nGroups = 3; else 275 if (s->nMTF < 1200) nGroups = 4; else 276 if (s->nMTF < 2400) nGroups = 5; else 277 nGroups = 6; 278 279 /*--- Generate an initial set of coding tables ---*/ 280 { 281 Int32 nPart, remF, tFreq, aFreq; 282 283 nPart = nGroups; 284 remF = s->nMTF; 285 gs = 0; 286 while (nPart > 0) { 287 tFreq = remF / nPart; 288 ge = gs-1; 289 aFreq = 0; 290 while (aFreq < tFreq && ge < alphaSize-1) { 291 ge++; 292 aFreq += s->mtfFreq[ge]; 293 } 294 295 if (ge > gs 296 && nPart != nGroups && nPart != 1 297 && ((nGroups-nPart) % 2 == 1)) { 298 aFreq -= s->mtfFreq[ge]; 299 ge--; 300 } 301 302 if (s->verbosity >= 3) 303 VPrintf5( " initial group %d, [%d .. %d], " 304 "has %d syms (%4.1f%%)\n", 305 nPart, gs, ge, aFreq, 306 (100.0 * (float)aFreq) / (float)(s->nMTF) ); 307 308 for (v = 0; v < alphaSize; v++) 309 if (v >= gs && v <= ge) 310 s->len[nPart-1][v] = BZ_LESSER_ICOST; else 311 s->len[nPart-1][v] = BZ_GREATER_ICOST; 312 313 nPart--; 314 gs = ge+1; 315 remF -= aFreq; 316 } 317 } 318 319 /*--- 320 Iterate up to BZ_N_ITERS times to improve the tables. 321 ---*/ 322 for (iter = 0; iter < BZ_N_ITERS; iter++) { 323 324 for (t = 0; t < nGroups; t++) fave[t] = 0; 325 326 for (t = 0; t < nGroups; t++) 327 for (v = 0; v < alphaSize; v++) 328 s->rfreq[t][v] = 0; 329 330 /*--- 331 Set up an auxiliary length table which is used to fast-track 332 the common case (nGroups == 6). 333 ---*/ 334 if (nGroups == 6) { 335 for (v = 0; v < alphaSize; v++) { 336 s->len_pack[v][0] = (s->len[1][v] << 16) | s->len[0][v]; 337 s->len_pack[v][1] = (s->len[3][v] << 16) | s->len[2][v]; 338 s->len_pack[v][2] = (s->len[5][v] << 16) | s->len[4][v]; 339 } 340 } 341 342 nSelectors = 0; 343 totc = 0; 344 gs = 0; 345 while (True) { 346 347 /*--- Set group start & end marks. --*/ 348 if (gs >= s->nMTF) break; 349 ge = gs + BZ_G_SIZE - 1; 350 if (ge >= s->nMTF) ge = s->nMTF-1; 351 352 /*-- 353 Calculate the cost of this group as coded 354 by each of the coding tables. 355 --*/ 356 for (t = 0; t < nGroups; t++) cost[t] = 0; 357 358 if (nGroups == 6 && 50 == ge-gs+1) { 359 /*--- fast track the common case ---*/ 360 register UInt32 cost01, cost23, cost45; 361 register UInt16 icv; 362 cost01 = cost23 = cost45 = 0; 363 364 # define BZ_ITER(nn) \ 365 icv = mtfv[gs+(nn)]; \ 366 cost01 += s->len_pack[icv][0]; \ 367 cost23 += s->len_pack[icv][1]; \ 368 cost45 += s->len_pack[icv][2]; \ 369 370 BZ_ITER(0); BZ_ITER(1); BZ_ITER(2); BZ_ITER(3); BZ_ITER(4); 371 BZ_ITER(5); BZ_ITER(6); BZ_ITER(7); BZ_ITER(8); BZ_ITER(9); 372 BZ_ITER(10); BZ_ITER(11); BZ_ITER(12); BZ_ITER(13); BZ_ITER(14); 373 BZ_ITER(15); BZ_ITER(16); BZ_ITER(17); BZ_ITER(18); BZ_ITER(19); 374 BZ_ITER(20); BZ_ITER(21); BZ_ITER(22); BZ_ITER(23); BZ_ITER(24); 375 BZ_ITER(25); BZ_ITER(26); BZ_ITER(27); BZ_ITER(28); BZ_ITER(29); 376 BZ_ITER(30); BZ_ITER(31); BZ_ITER(32); BZ_ITER(33); BZ_ITER(34); 377 BZ_ITER(35); BZ_ITER(36); BZ_ITER(37); BZ_ITER(38); BZ_ITER(39); 378 BZ_ITER(40); BZ_ITER(41); BZ_ITER(42); BZ_ITER(43); BZ_ITER(44); 379 BZ_ITER(45); BZ_ITER(46); BZ_ITER(47); BZ_ITER(48); BZ_ITER(49); 380 381 # undef BZ_ITER 382 383 cost[0] = cost01 & 0xffff; cost[1] = cost01 >> 16; 384 cost[2] = cost23 & 0xffff; cost[3] = cost23 >> 16; 385 cost[4] = cost45 & 0xffff; cost[5] = cost45 >> 16; 386 387 } else { 388 /*--- slow version which correctly handles all situations ---*/ 389 for (i = gs; i <= ge; i++) { 390 UInt16 icv = mtfv[i]; 391 for (t = 0; t < nGroups; t++) cost[t] += s->len[t][icv]; 392 } 393 } 394 395 /*-- 396 Find the coding table which is best for this group, 397 and record its identity in the selector table. 398 --*/ 399 bc = 999999999; bt = -1; 400 for (t = 0; t < nGroups; t++) 401 if (cost[t] < bc) { bc = cost[t]; bt = t; }; 402 totc += bc; 403 fave[bt]++; 404 s->selector[nSelectors] = bt; 405 nSelectors++; 406 407 /*-- 408 Increment the symbol frequencies for the selected table. 409 --*/ 410 if (nGroups == 6 && 50 == ge-gs+1) { 411 /*--- fast track the common case ---*/ 412 413 # define BZ_ITUR(nn) s->rfreq[bt][ mtfv[gs+(nn)] ]++ 414 415 BZ_ITUR(0); BZ_ITUR(1); BZ_ITUR(2); BZ_ITUR(3); BZ_ITUR(4); 416 BZ_ITUR(5); BZ_ITUR(6); BZ_ITUR(7); BZ_ITUR(8); BZ_ITUR(9); 417 BZ_ITUR(10); BZ_ITUR(11); BZ_ITUR(12); BZ_ITUR(13); BZ_ITUR(14); 418 BZ_ITUR(15); BZ_ITUR(16); BZ_ITUR(17); BZ_ITUR(18); BZ_ITUR(19); 419 BZ_ITUR(20); BZ_ITUR(21); BZ_ITUR(22); BZ_ITUR(23); BZ_ITUR(24); 420 BZ_ITUR(25); BZ_ITUR(26); BZ_ITUR(27); BZ_ITUR(28); BZ_ITUR(29); 421 BZ_ITUR(30); BZ_ITUR(31); BZ_ITUR(32); BZ_ITUR(33); BZ_ITUR(34); 422 BZ_ITUR(35); BZ_ITUR(36); BZ_ITUR(37); BZ_ITUR(38); BZ_ITUR(39); 423 BZ_ITUR(40); BZ_ITUR(41); BZ_ITUR(42); BZ_ITUR(43); BZ_ITUR(44); 424 BZ_ITUR(45); BZ_ITUR(46); BZ_ITUR(47); BZ_ITUR(48); BZ_ITUR(49); 425 426 # undef BZ_ITUR 427 428 } else { 429 /*--- slow version which correctly handles all situations ---*/ 430 for (i = gs; i <= ge; i++) 431 s->rfreq[bt][ mtfv[i] ]++; 432 } 433 434 gs = ge+1; 435 } 436 if (s->verbosity >= 3) { 437 VPrintf2 ( " pass %d: size is %d, grp uses are ", 438 iter+1, totc/8 ); 439 for (t = 0; t < nGroups; t++) 440 VPrintf1 ( "%d ", fave[t] ); 441 VPrintf0 ( "\n" ); 442 } 443 444 /*-- 445 Recompute the tables based on the accumulated frequencies. 446 --*/ 447 /* maxLen was changed from 20 to 17 in bzip2-1.0.3. See 448 comment in huffman.c for details. */ 449 for (t = 0; t < nGroups; t++) 450 BZ2_hbMakeCodeLengths ( &(s->len[t][0]), &(s->rfreq[t][0]), 451 alphaSize, 17 /*20*/ ); 452 } 453 454 455 AssertH( nGroups < 8, 3002 ); 456 AssertH( nSelectors < 32768 && 457 nSelectors <= (2 + (900000 / BZ_G_SIZE)), 458 3003 ); 459 460 461 /*--- Compute MTF values for the selectors. ---*/ 462 { 463 UChar pos[BZ_N_GROUPS], ll_i, tmp2, tmp; 464 for (i = 0; i < nGroups; i++) pos[i] = i; 465 for (i = 0; i < nSelectors; i++) { 466 ll_i = s->selector[i]; 467 j = 0; 468 tmp = pos[j]; 469 while ( ll_i != tmp ) { 470 j++; 471 tmp2 = tmp; 472 tmp = pos[j]; 473 pos[j] = tmp2; 474 }; 475 pos[0] = tmp; 476 s->selectorMtf[i] = j; 477 } 478 }; 479 480 /*--- Assign actual codes for the tables. --*/ 481 for (t = 0; t < nGroups; t++) { 482 minLen = 32; 483 maxLen = 0; 484 for (i = 0; i < alphaSize; i++) { 485 if (s->len[t][i] > maxLen) maxLen = s->len[t][i]; 486 if (s->len[t][i] < minLen) minLen = s->len[t][i]; 487 } 488 AssertH ( !(maxLen > 17 /*20*/ ), 3004 ); 489 AssertH ( !(minLen < 1), 3005 ); 490 BZ2_hbAssignCodes ( &(s->code[t][0]), &(s->len[t][0]), 491 minLen, maxLen, alphaSize ); 492 } 493 494 /*--- Transmit the mapping table. ---*/ 495 { 496 Bool inUse16[16]; 497 for (i = 0; i < 16; i++) { 498 inUse16[i] = False; 499 for (j = 0; j < 16; j++) 500 if (s->inUse[i * 16 + j]) inUse16[i] = True; 501 } 502 503 nBytes = s->numZ; 504 for (i = 0; i < 16; i++) 505 if (inUse16[i]) bsW(s,1,1); else bsW(s,1,0); 506 507 for (i = 0; i < 16; i++) 508 if (inUse16[i]) 509 for (j = 0; j < 16; j++) { 510 if (s->inUse[i * 16 + j]) bsW(s,1,1); else bsW(s,1,0); 511 } 512 513 if (s->verbosity >= 3) 514 VPrintf1( " bytes: mapping %d, ", s->numZ-nBytes ); 515 } 516 517 /*--- Now the selectors. ---*/ 518 nBytes = s->numZ; 519 bsW ( s, 3, nGroups ); 520 bsW ( s, 15, nSelectors ); 521 for (i = 0; i < nSelectors; i++) { 522 for (j = 0; j < s->selectorMtf[i]; j++) bsW(s,1,1); 523 bsW(s,1,0); 524 } 525 if (s->verbosity >= 3) 526 VPrintf1( "selectors %d, ", s->numZ-nBytes ); 527 528 /*--- Now the coding tables. ---*/ 529 nBytes = s->numZ; 530 531 for (t = 0; t < nGroups; t++) { 532 Int32 curr = s->len[t][0]; 533 bsW ( s, 5, curr ); 534 for (i = 0; i < alphaSize; i++) { 535 while (curr < s->len[t][i]) { bsW(s,2,2); curr++; /* 10 */ }; 536 while (curr > s->len[t][i]) { bsW(s,2,3); curr--; /* 11 */ }; 537 bsW ( s, 1, 0 ); 538 } 539 } 540 541 if (s->verbosity >= 3) 542 VPrintf1 ( "code lengths %d, ", s->numZ-nBytes ); 543 544 /*--- And finally, the block data proper ---*/ 545 nBytes = s->numZ; 546 selCtr = 0; 547 gs = 0; 548 while (True) { 549 if (gs >= s->nMTF) break; 550 ge = gs + BZ_G_SIZE - 1; 551 if (ge >= s->nMTF) ge = s->nMTF-1; 552 AssertH ( s->selector[selCtr] < nGroups, 3006 ); 553 554 if (nGroups == 6 && 50 == ge-gs+1) { 555 /*--- fast track the common case ---*/ 556 UInt16 mtfv_i; 557 UChar* s_len_sel_selCtr 558 = &(s->len[s->selector[selCtr]][0]); 559 Int32* s_code_sel_selCtr 560 = &(s->code[s->selector[selCtr]][0]); 561 562 # define BZ_ITAH(nn) \ 563 mtfv_i = mtfv[gs+(nn)]; \ 564 bsW ( s, \ 565 s_len_sel_selCtr[mtfv_i], \ 566 s_code_sel_selCtr[mtfv_i] ) 567 568 BZ_ITAH(0); BZ_ITAH(1); BZ_ITAH(2); BZ_ITAH(3); BZ_ITAH(4); 569 BZ_ITAH(5); BZ_ITAH(6); BZ_ITAH(7); BZ_ITAH(8); BZ_ITAH(9); 570 BZ_ITAH(10); BZ_ITAH(11); BZ_ITAH(12); BZ_ITAH(13); BZ_ITAH(14); 571 BZ_ITAH(15); BZ_ITAH(16); BZ_ITAH(17); BZ_ITAH(18); BZ_ITAH(19); 572 BZ_ITAH(20); BZ_ITAH(21); BZ_ITAH(22); BZ_ITAH(23); BZ_ITAH(24); 573 BZ_ITAH(25); BZ_ITAH(26); BZ_ITAH(27); BZ_ITAH(28); BZ_ITAH(29); 574 BZ_ITAH(30); BZ_ITAH(31); BZ_ITAH(32); BZ_ITAH(33); BZ_ITAH(34); 575 BZ_ITAH(35); BZ_ITAH(36); BZ_ITAH(37); BZ_ITAH(38); BZ_ITAH(39); 576 BZ_ITAH(40); BZ_ITAH(41); BZ_ITAH(42); BZ_ITAH(43); BZ_ITAH(44); 577 BZ_ITAH(45); BZ_ITAH(46); BZ_ITAH(47); BZ_ITAH(48); BZ_ITAH(49); 578 579 # undef BZ_ITAH 580 581 } else { 582 /*--- slow version which correctly handles all situations ---*/ 583 for (i = gs; i <= ge; i++) { 584 bsW ( s, 585 s->len [s->selector[selCtr]] [mtfv[i]], 586 s->code [s->selector[selCtr]] [mtfv[i]] ); 587 } 588 } 589 590 591 gs = ge+1; 592 selCtr++; 593 } 594 AssertH( selCtr == nSelectors, 3007 ); 595 596 if (s->verbosity >= 3) 597 VPrintf1( "codes %d\n", s->numZ-nBytes ); 598 } 599 600 601 /*---------------------------------------------------*/ 602 void BZ2_compressBlock ( EState* s, Bool is_last_block ) 603 { 604 if (s->nblock > 0) { 605 606 BZ_FINALISE_CRC ( s->blockCRC ); 607 s->combinedCRC = (s->combinedCRC << 1) | (s->combinedCRC >> 31); 608 s->combinedCRC ^= s->blockCRC; 609 if (s->blockNo > 1) s->numZ = 0; 610 611 if (s->verbosity >= 2) 612 VPrintf4( " block %d: crc = 0x%08x, " 613 "combined CRC = 0x%08x, size = %d\n", 614 s->blockNo, s->blockCRC, s->combinedCRC, s->nblock ); 615 616 BZ2_blockSort ( s ); 617 } 618 619 s->zbits = (UChar*) (&((UChar*)s->arr2)[s->nblock]); 620 621 /*-- If this is the first block, create the stream header. --*/ 622 if (s->blockNo == 1) { 623 BZ2_bsInitWrite ( s ); 624 bsPutUChar ( s, BZ_HDR_B ); 625 bsPutUChar ( s, BZ_HDR_Z ); 626 bsPutUChar ( s, BZ_HDR_h ); 627 bsPutUChar ( s, (UChar)(BZ_HDR_0 + s->blockSize100k) ); 628 } 629 630 if (s->nblock > 0) { 631 632 bsPutUChar ( s, 0x31 ); bsPutUChar ( s, 0x41 ); 633 bsPutUChar ( s, 0x59 ); bsPutUChar ( s, 0x26 ); 634 bsPutUChar ( s, 0x53 ); bsPutUChar ( s, 0x59 ); 635 636 /*-- Now the block's CRC, so it is in a known place. --*/ 637 bsPutUInt32 ( s, s->blockCRC ); 638 639 /*-- 640 Now a single bit indicating (non-)randomisation. 641 As of version 0.9.5, we use a better sorting algorithm 642 which makes randomisation unnecessary. So always set 643 the randomised bit to 'no'. Of course, the decoder 644 still needs to be able to handle randomised blocks 645 so as to maintain backwards compatibility with 646 older versions of bzip2. 647 --*/ 648 bsW(s,1,0); 649 650 bsW ( s, 24, s->origPtr ); 651 generateMTFValues ( s ); 652 sendMTFValues ( s ); 653 } 654 655 656 /*-- If this is the last block, add the stream trailer. --*/ 657 if (is_last_block) { 658 659 bsPutUChar ( s, 0x17 ); bsPutUChar ( s, 0x72 ); 660 bsPutUChar ( s, 0x45 ); bsPutUChar ( s, 0x38 ); 661 bsPutUChar ( s, 0x50 ); bsPutUChar ( s, 0x90 ); 662 bsPutUInt32 ( s, s->combinedCRC ); 663 if (s->verbosity >= 2) 664 VPrintf1( " final combined CRC = 0x%08x\n ", s->combinedCRC ); 665 bsFinishWrite ( s ); 666 } 667 } 668 669 670 /*-------------------------------------------------------------*/ 671 /*--- end compress.c ---*/ 672 /*-------------------------------------------------------------*/ 673