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 1.0.8 of 13 July 2019 12 Copyright (C) 1996-2019 Julian Seward <jseward@acm.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 ((void)nBytes); /* Silence variable ‘nBytes’ set but not used warning */ 262 if (s->verbosity >= 3) 263 VPrintf3( " %d in block, %d after MTF & 1-2 coding, " 264 "%d+2 syms in use\n", 265 s->nblock, s->nMTF, s->nInUse ); 266 267 alphaSize = s->nInUse+2; 268 for (t = 0; t < BZ_N_GROUPS; t++) 269 for (v = 0; v < alphaSize; v++) 270 s->len[t][v] = BZ_GREATER_ICOST; 271 272 /*--- Decide how many coding tables to use ---*/ 273 AssertH ( s->nMTF > 0, 3001 ); 274 if (s->nMTF < 200) nGroups = 2; else 275 if (s->nMTF < 600) nGroups = 3; else 276 if (s->nMTF < 1200) nGroups = 4; else 277 if (s->nMTF < 2400) nGroups = 5; else 278 nGroups = 6; 279 280 /*--- Generate an initial set of coding tables ---*/ 281 { 282 Int32 nPart, remF, tFreq, aFreq; 283 284 nPart = nGroups; 285 remF = s->nMTF; 286 gs = 0; 287 while (nPart > 0) { 288 tFreq = remF / nPart; 289 ge = gs-1; 290 aFreq = 0; 291 while (aFreq < tFreq && ge < alphaSize-1) { 292 ge++; 293 aFreq += s->mtfFreq[ge]; 294 } 295 296 if (ge > gs 297 && nPart != nGroups && nPart != 1 298 && ((nGroups-nPart) % 2 == 1)) { 299 aFreq -= s->mtfFreq[ge]; 300 ge--; 301 } 302 303 if (s->verbosity >= 3) 304 VPrintf5( " initial group %d, [%d .. %d], " 305 "has %d syms (%4.1f%%)\n", 306 nPart, gs, ge, aFreq, 307 (100.0 * (float)aFreq) / (float)(s->nMTF) ); 308 309 for (v = 0; v < alphaSize; v++) 310 if (v >= gs && v <= ge) 311 s->len[nPart-1][v] = BZ_LESSER_ICOST; else 312 s->len[nPart-1][v] = BZ_GREATER_ICOST; 313 314 nPart--; 315 gs = ge+1; 316 remF -= aFreq; 317 } 318 } 319 320 /*--- 321 Iterate up to BZ_N_ITERS times to improve the tables. 322 ---*/ 323 for (iter = 0; iter < BZ_N_ITERS; iter++) { 324 325 for (t = 0; t < nGroups; t++) fave[t] = 0; 326 327 for (t = 0; t < nGroups; t++) 328 for (v = 0; v < alphaSize; v++) 329 s->rfreq[t][v] = 0; 330 331 /*--- 332 Set up an auxiliary length table which is used to fast-track 333 the common case (nGroups == 6). 334 ---*/ 335 if (nGroups == 6) { 336 for (v = 0; v < alphaSize; v++) { 337 s->len_pack[v][0] = (s->len[1][v] << 16) | s->len[0][v]; 338 s->len_pack[v][1] = (s->len[3][v] << 16) | s->len[2][v]; 339 s->len_pack[v][2] = (s->len[5][v] << 16) | s->len[4][v]; 340 } 341 } 342 343 nSelectors = 0; 344 totc = 0; 345 gs = 0; 346 while (True) { 347 348 /*--- Set group start & end marks. --*/ 349 if (gs >= s->nMTF) break; 350 ge = gs + BZ_G_SIZE - 1; 351 if (ge >= s->nMTF) ge = s->nMTF-1; 352 353 /*-- 354 Calculate the cost of this group as coded 355 by each of the coding tables. 356 --*/ 357 for (t = 0; t < nGroups; t++) cost[t] = 0; 358 359 if (nGroups == 6 && 50 == ge-gs+1) { 360 /*--- fast track the common case ---*/ 361 register UInt32 cost01, cost23, cost45; 362 register UInt16 icv; 363 cost01 = cost23 = cost45 = 0; 364 365 # define BZ_ITER(nn) \ 366 icv = mtfv[gs+(nn)]; \ 367 cost01 += s->len_pack[icv][0]; \ 368 cost23 += s->len_pack[icv][1]; \ 369 cost45 += s->len_pack[icv][2]; \ 370 371 BZ_ITER(0); BZ_ITER(1); BZ_ITER(2); BZ_ITER(3); BZ_ITER(4); 372 BZ_ITER(5); BZ_ITER(6); BZ_ITER(7); BZ_ITER(8); BZ_ITER(9); 373 BZ_ITER(10); BZ_ITER(11); BZ_ITER(12); BZ_ITER(13); BZ_ITER(14); 374 BZ_ITER(15); BZ_ITER(16); BZ_ITER(17); BZ_ITER(18); BZ_ITER(19); 375 BZ_ITER(20); BZ_ITER(21); BZ_ITER(22); BZ_ITER(23); BZ_ITER(24); 376 BZ_ITER(25); BZ_ITER(26); BZ_ITER(27); BZ_ITER(28); BZ_ITER(29); 377 BZ_ITER(30); BZ_ITER(31); BZ_ITER(32); BZ_ITER(33); BZ_ITER(34); 378 BZ_ITER(35); BZ_ITER(36); BZ_ITER(37); BZ_ITER(38); BZ_ITER(39); 379 BZ_ITER(40); BZ_ITER(41); BZ_ITER(42); BZ_ITER(43); BZ_ITER(44); 380 BZ_ITER(45); BZ_ITER(46); BZ_ITER(47); BZ_ITER(48); BZ_ITER(49); 381 382 # undef BZ_ITER 383 384 cost[0] = cost01 & 0xffff; cost[1] = cost01 >> 16; 385 cost[2] = cost23 & 0xffff; cost[3] = cost23 >> 16; 386 cost[4] = cost45 & 0xffff; cost[5] = cost45 >> 16; 387 388 } else { 389 /*--- slow version which correctly handles all situations ---*/ 390 for (i = gs; i <= ge; i++) { 391 UInt16 icv = mtfv[i]; 392 for (t = 0; t < nGroups; t++) cost[t] += s->len[t][icv]; 393 } 394 } 395 396 /*-- 397 Find the coding table which is best for this group, 398 and record its identity in the selector table. 399 --*/ 400 bc = 999999999; bt = -1; 401 for (t = 0; t < nGroups; t++) 402 if (cost[t] < bc) { bc = cost[t]; bt = t; }; 403 totc += bc; 404 fave[bt]++; 405 s->selector[nSelectors] = bt; 406 nSelectors++; 407 408 /*-- 409 Increment the symbol frequencies for the selected table. 410 --*/ 411 if (nGroups == 6 && 50 == ge-gs+1) { 412 /*--- fast track the common case ---*/ 413 414 # define BZ_ITUR(nn) s->rfreq[bt][ mtfv[gs+(nn)] ]++ 415 416 BZ_ITUR(0); BZ_ITUR(1); BZ_ITUR(2); BZ_ITUR(3); BZ_ITUR(4); 417 BZ_ITUR(5); BZ_ITUR(6); BZ_ITUR(7); BZ_ITUR(8); BZ_ITUR(9); 418 BZ_ITUR(10); BZ_ITUR(11); BZ_ITUR(12); BZ_ITUR(13); BZ_ITUR(14); 419 BZ_ITUR(15); BZ_ITUR(16); BZ_ITUR(17); BZ_ITUR(18); BZ_ITUR(19); 420 BZ_ITUR(20); BZ_ITUR(21); BZ_ITUR(22); BZ_ITUR(23); BZ_ITUR(24); 421 BZ_ITUR(25); BZ_ITUR(26); BZ_ITUR(27); BZ_ITUR(28); BZ_ITUR(29); 422 BZ_ITUR(30); BZ_ITUR(31); BZ_ITUR(32); BZ_ITUR(33); BZ_ITUR(34); 423 BZ_ITUR(35); BZ_ITUR(36); BZ_ITUR(37); BZ_ITUR(38); BZ_ITUR(39); 424 BZ_ITUR(40); BZ_ITUR(41); BZ_ITUR(42); BZ_ITUR(43); BZ_ITUR(44); 425 BZ_ITUR(45); BZ_ITUR(46); BZ_ITUR(47); BZ_ITUR(48); BZ_ITUR(49); 426 427 # undef BZ_ITUR 428 429 } else { 430 /*--- slow version which correctly handles all situations ---*/ 431 for (i = gs; i <= ge; i++) 432 s->rfreq[bt][ mtfv[i] ]++; 433 } 434 435 gs = ge+1; 436 } 437 if (s->verbosity >= 3) { 438 VPrintf2 ( " pass %d: size is %d, grp uses are ", 439 iter+1, totc/8 ); 440 for (t = 0; t < nGroups; t++) 441 VPrintf1 ( "%d ", fave[t] ); 442 VPrintf0 ( "\n" ); 443 } 444 445 /*-- 446 Recompute the tables based on the accumulated frequencies. 447 --*/ 448 /* maxLen was changed from 20 to 17 in bzip2-1.0.3. See 449 comment in huffman.c for details. */ 450 for (t = 0; t < nGroups; t++) 451 BZ2_hbMakeCodeLengths ( &(s->len[t][0]), &(s->rfreq[t][0]), 452 alphaSize, 17 /*20*/ ); 453 } 454 455 456 AssertH( nGroups < 8, 3002 ); 457 AssertH( nSelectors < 32768 && 458 nSelectors <= BZ_MAX_SELECTORS, 459 3003 ); 460 461 462 /*--- Compute MTF values for the selectors. ---*/ 463 { 464 UChar pos[BZ_N_GROUPS], ll_i, tmp2, tmp; 465 for (i = 0; i < nGroups; i++) pos[i] = i; 466 for (i = 0; i < nSelectors; i++) { 467 ll_i = s->selector[i]; 468 j = 0; 469 tmp = pos[j]; 470 while ( ll_i != tmp ) { 471 j++; 472 tmp2 = tmp; 473 tmp = pos[j]; 474 pos[j] = tmp2; 475 }; 476 pos[0] = tmp; 477 s->selectorMtf[i] = j; 478 } 479 }; 480 481 /*--- Assign actual codes for the tables. --*/ 482 for (t = 0; t < nGroups; t++) { 483 minLen = 32; 484 maxLen = 0; 485 for (i = 0; i < alphaSize; i++) { 486 if (s->len[t][i] > maxLen) maxLen = s->len[t][i]; 487 if (s->len[t][i] < minLen) minLen = s->len[t][i]; 488 } 489 AssertH ( !(maxLen > 17 /*20*/ ), 3004 ); 490 AssertH ( !(minLen < 1), 3005 ); 491 BZ2_hbAssignCodes ( &(s->code[t][0]), &(s->len[t][0]), 492 minLen, maxLen, alphaSize ); 493 } 494 495 /*--- Transmit the mapping table. ---*/ 496 { 497 Bool inUse16[16]; 498 for (i = 0; i < 16; i++) { 499 inUse16[i] = False; 500 for (j = 0; j < 16; j++) 501 if (s->inUse[i * 16 + j]) inUse16[i] = True; 502 } 503 504 nBytes = s->numZ; 505 for (i = 0; i < 16; i++) 506 if (inUse16[i]) bsW(s,1,1); else bsW(s,1,0); 507 508 for (i = 0; i < 16; i++) 509 if (inUse16[i]) 510 for (j = 0; j < 16; j++) { 511 if (s->inUse[i * 16 + j]) bsW(s,1,1); else bsW(s,1,0); 512 } 513 514 if (s->verbosity >= 3) 515 VPrintf1( " bytes: mapping %d, ", s->numZ-nBytes ); 516 } 517 518 /*--- Now the selectors. ---*/ 519 nBytes = s->numZ; 520 bsW ( s, 3, nGroups ); 521 bsW ( s, 15, nSelectors ); 522 for (i = 0; i < nSelectors; i++) { 523 for (j = 0; j < s->selectorMtf[i]; j++) bsW(s,1,1); 524 bsW(s,1,0); 525 } 526 if (s->verbosity >= 3) 527 VPrintf1( "selectors %d, ", s->numZ-nBytes ); 528 529 /*--- Now the coding tables. ---*/ 530 nBytes = s->numZ; 531 532 for (t = 0; t < nGroups; t++) { 533 Int32 curr = s->len[t][0]; 534 bsW ( s, 5, curr ); 535 for (i = 0; i < alphaSize; i++) { 536 while (curr < s->len[t][i]) { bsW(s,2,2); curr++; /* 10 */ }; 537 while (curr > s->len[t][i]) { bsW(s,2,3); curr--; /* 11 */ }; 538 bsW ( s, 1, 0 ); 539 } 540 } 541 542 if (s->verbosity >= 3) 543 VPrintf1 ( "code lengths %d, ", s->numZ-nBytes ); 544 545 /*--- And finally, the block data proper ---*/ 546 nBytes = s->numZ; 547 selCtr = 0; 548 gs = 0; 549 while (True) { 550 if (gs >= s->nMTF) break; 551 ge = gs + BZ_G_SIZE - 1; 552 if (ge >= s->nMTF) ge = s->nMTF-1; 553 AssertH ( s->selector[selCtr] < nGroups, 3006 ); 554 555 if (nGroups == 6 && 50 == ge-gs+1) { 556 /*--- fast track the common case ---*/ 557 UInt16 mtfv_i; 558 UChar* s_len_sel_selCtr 559 = &(s->len[s->selector[selCtr]][0]); 560 Int32* s_code_sel_selCtr 561 = &(s->code[s->selector[selCtr]][0]); 562 563 # define BZ_ITAH(nn) \ 564 mtfv_i = mtfv[gs+(nn)]; \ 565 bsW ( s, \ 566 s_len_sel_selCtr[mtfv_i], \ 567 s_code_sel_selCtr[mtfv_i] ) 568 569 BZ_ITAH(0); BZ_ITAH(1); BZ_ITAH(2); BZ_ITAH(3); BZ_ITAH(4); 570 BZ_ITAH(5); BZ_ITAH(6); BZ_ITAH(7); BZ_ITAH(8); BZ_ITAH(9); 571 BZ_ITAH(10); BZ_ITAH(11); BZ_ITAH(12); BZ_ITAH(13); BZ_ITAH(14); 572 BZ_ITAH(15); BZ_ITAH(16); BZ_ITAH(17); BZ_ITAH(18); BZ_ITAH(19); 573 BZ_ITAH(20); BZ_ITAH(21); BZ_ITAH(22); BZ_ITAH(23); BZ_ITAH(24); 574 BZ_ITAH(25); BZ_ITAH(26); BZ_ITAH(27); BZ_ITAH(28); BZ_ITAH(29); 575 BZ_ITAH(30); BZ_ITAH(31); BZ_ITAH(32); BZ_ITAH(33); BZ_ITAH(34); 576 BZ_ITAH(35); BZ_ITAH(36); BZ_ITAH(37); BZ_ITAH(38); BZ_ITAH(39); 577 BZ_ITAH(40); BZ_ITAH(41); BZ_ITAH(42); BZ_ITAH(43); BZ_ITAH(44); 578 BZ_ITAH(45); BZ_ITAH(46); BZ_ITAH(47); BZ_ITAH(48); BZ_ITAH(49); 579 580 # undef BZ_ITAH 581 582 } else { 583 /*--- slow version which correctly handles all situations ---*/ 584 for (i = gs; i <= ge; i++) { 585 bsW ( s, 586 s->len [s->selector[selCtr]] [mtfv[i]], 587 s->code [s->selector[selCtr]] [mtfv[i]] ); 588 } 589 } 590 591 592 gs = ge+1; 593 selCtr++; 594 } 595 AssertH( selCtr == nSelectors, 3007 ); 596 597 if (s->verbosity >= 3) 598 VPrintf1( "codes %d\n", s->numZ-nBytes ); 599 } 600 601 602 /*---------------------------------------------------*/ 603 void BZ2_compressBlock ( EState* s, Bool is_last_block ) 604 { 605 if (s->nblock > 0) { 606 607 BZ_FINALISE_CRC ( s->blockCRC ); 608 s->combinedCRC = (s->combinedCRC << 1) | (s->combinedCRC >> 31); 609 s->combinedCRC ^= s->blockCRC; 610 if (s->blockNo > 1) s->numZ = 0; 611 612 if (s->verbosity >= 2) 613 VPrintf4( " block %d: crc = 0x%08x, " 614 "combined CRC = 0x%08x, size = %d\n", 615 s->blockNo, s->blockCRC, s->combinedCRC, s->nblock ); 616 617 BZ2_blockSort ( s ); 618 } 619 620 s->zbits = (UChar*) (&((UChar*)s->arr2)[s->nblock]); 621 622 /*-- If this is the first block, create the stream header. --*/ 623 if (s->blockNo == 1) { 624 BZ2_bsInitWrite ( s ); 625 bsPutUChar ( s, BZ_HDR_B ); 626 bsPutUChar ( s, BZ_HDR_Z ); 627 bsPutUChar ( s, BZ_HDR_h ); 628 bsPutUChar ( s, (UChar)(BZ_HDR_0 + s->blockSize100k) ); 629 } 630 631 if (s->nblock > 0) { 632 633 bsPutUChar ( s, 0x31 ); bsPutUChar ( s, 0x41 ); 634 bsPutUChar ( s, 0x59 ); bsPutUChar ( s, 0x26 ); 635 bsPutUChar ( s, 0x53 ); bsPutUChar ( s, 0x59 ); 636 637 /*-- Now the block's CRC, so it is in a known place. --*/ 638 bsPutUInt32 ( s, s->blockCRC ); 639 640 /*-- 641 Now a single bit indicating (non-)randomisation. 642 As of version 0.9.5, we use a better sorting algorithm 643 which makes randomisation unnecessary. So always set 644 the randomised bit to 'no'. Of course, the decoder 645 still needs to be able to handle randomised blocks 646 so as to maintain backwards compatibility with 647 older versions of bzip2. 648 --*/ 649 bsW(s,1,0); 650 651 bsW ( s, 24, s->origPtr ); 652 generateMTFValues ( s ); 653 sendMTFValues ( s ); 654 } 655 656 657 /*-- If this is the last block, add the stream trailer. --*/ 658 if (is_last_block) { 659 660 bsPutUChar ( s, 0x17 ); bsPutUChar ( s, 0x72 ); 661 bsPutUChar ( s, 0x45 ); bsPutUChar ( s, 0x38 ); 662 bsPutUChar ( s, 0x50 ); bsPutUChar ( s, 0x90 ); 663 bsPutUInt32 ( s, s->combinedCRC ); 664 if (s->verbosity >= 2) 665 VPrintf1( " final combined CRC = 0x%08x\n ", s->combinedCRC ); 666 bsFinishWrite ( s ); 667 } 668 } 669 670 671 /*-------------------------------------------------------------*/ 672 /*--- end compress.c ---*/ 673 /*-------------------------------------------------------------*/ 674