1/* 2 * Copyright (c) 2008 Apple Inc. All rights reserved. 3 * 4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ 5 * 6 * This file contains Original Code and/or Modifications of Original Code 7 * as defined in and that are subject to the Apple Public Source License 8 * Version 2.0 (the 'License'). You may not use this file except in 9 * compliance with the License. The rights granted to you under the License 10 * may not be used to create, or enable the creation or redistribution of, 11 * unlawful or unlicensed copies of an Apple operating system, or to 12 * circumvent, violate, or enable the circumvention or violation of, any 13 * terms of an Apple operating system software license agreement. 14 * 15 * Please obtain a copy of the License at 16 * http://www.opensource.apple.com/apsl/ and read it before using this file. 17 * 18 * The Original Code and all software distributed under the License are 19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 23 * Please see the License for the specific language governing rights and 24 * limitations under the License. 25 * 26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ 27 */ 28/* trees.c -- output deflated data using Huffman coding 29 * Copyright (C) 1995-2005 Jean-loup Gailly 30 * For conditions of distribution and use, see copyright notice in zlib.h 31 */ 32 33/* 34 * ALGORITHM 35 * 36 * The "deflation" process uses several Huffman trees. The more 37 * common source values are represented by shorter bit sequences. 38 * 39 * Each code tree is stored in a compressed form which is itself 40 * a Huffman encoding of the lengths of all the code strings (in 41 * ascending order by source values). The actual code strings are 42 * reconstructed from the lengths in the inflate process, as described 43 * in the deflate specification. 44 * 45 * REFERENCES 46 * 47 * Deutsch, L.P.,"'Deflate' Compressed Data Format Specification". 48 * Available in ftp.uu.net:/pub/archiving/zip/doc/deflate-1.1.doc 49 * 50 * Storer, James A. 51 * Data Compression: Methods and Theory, pp. 49-50. 52 * Computer Science Press, 1988. ISBN 0-7167-8156-5. 53 * 54 * Sedgewick, R. 55 * Algorithms, p290. 56 * Addison-Wesley, 1983. ISBN 0-201-06672-6. 57 */ 58 59/* @(#) $Id$ */ 60 61/* #define GEN_TREES_H */ 62 63#include "deflate.h" 64 65#ifdef DEBUG 66# include <ctype.h> 67#endif 68 69/* =========================================================================== 70 * Constants 71 */ 72 73#define MAX_BL_BITS 7 74/* Bit length codes must not exceed MAX_BL_BITS bits */ 75 76#define END_BLOCK 256 77/* end of block literal code */ 78 79#define REP_3_6 16 80/* repeat previous bit length 3-6 times (2 bits of repeat count) */ 81 82#define REPZ_3_10 17 83/* repeat a zero length 3-10 times (3 bits of repeat count) */ 84 85#define REPZ_11_138 18 86/* repeat a zero length 11-138 times (7 bits of repeat count) */ 87 88local const int extra_lbits[LENGTH_CODES] /* extra bits for each length code */ 89 = {0,0,0,0,0,0,0,0,1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4,5,5,5,5,0}; 90 91local const int extra_dbits[D_CODES] /* extra bits for each distance code */ 92 = {0,0,0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13}; 93 94local const int extra_blbits[BL_CODES]/* extra bits for each bit length code */ 95 = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7}; 96 97local const uch bl_order[BL_CODES] 98 = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15}; 99/* The lengths of the bit length codes are sent in order of decreasing 100 * probability, to avoid transmitting the lengths for unused bit length codes. 101 */ 102 103#define Buf_size (8 * 2*sizeof(char)) 104/* Number of bits used within bi_buf. (bi_buf might be implemented on 105 * more than 16 bits on some systems.) 106 */ 107 108/* =========================================================================== 109 * Local data. These are initialized only once. 110 */ 111 112#define DIST_CODE_LEN 512 /* see definition of array dist_code below */ 113 114#if defined(GEN_TREES_H) || !defined(STDC) 115/* non ANSI compilers may not accept trees.h */ 116 117local ct_data static_ltree[L_CODES+2]; 118/* The static literal tree. Since the bit lengths are imposed, there is no 119 * need for the L_CODES extra codes used during heap construction. However 120 * The codes 286 and 287 are needed to build a canonical tree (see _tr_init 121 * below). 122 */ 123 124local ct_data static_dtree[D_CODES]; 125/* The static distance tree. (Actually a trivial tree since all codes use 126 * 5 bits.) 127 */ 128 129uch _dist_code[DIST_CODE_LEN]; 130/* Distance codes. The first 256 values correspond to the distances 131 * 3 .. 258, the last 256 values correspond to the top 8 bits of 132 * the 15 bit distances. 133 */ 134 135uch _length_code[MAX_MATCH-MIN_MATCH+1]; 136/* length code for each normalized match length (0 == MIN_MATCH) */ 137 138local int base_length[LENGTH_CODES]; 139/* First normalized length for each code (0 = MIN_MATCH) */ 140 141local int base_dist[D_CODES]; 142/* First normalized distance for each code (0 = distance of 1) */ 143 144#else 145# include "trees.h" 146#endif /* GEN_TREES_H */ 147 148struct static_tree_desc_s { 149 const ct_data *static_tree; /* static tree or NULL */ 150 const intf *extra_bits; /* extra bits for each code or NULL */ 151 int extra_base; /* base index for extra_bits */ 152 int elems; /* max number of elements in the tree */ 153 int max_length; /* max bit length for the codes */ 154}; 155 156local static_tree_desc static_l_desc = 157{static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS}; 158 159local static_tree_desc static_d_desc = 160{static_dtree, extra_dbits, 0, D_CODES, MAX_BITS}; 161 162local static_tree_desc static_bl_desc = 163{(const ct_data *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS}; 164 165/* =========================================================================== 166 * Local (static) routines in this file. 167 */ 168 169local void tr_static_init OF((void)); 170local void init_block OF((deflate_state *s)); 171local void pqdownheap OF((deflate_state *s, ct_data *tree, int k)); 172local void gen_bitlen OF((deflate_state *s, tree_desc *desc)); 173local void gen_codes OF((ct_data *tree, int max_code, ushf *bl_count)); 174local void build_tree OF((deflate_state *s, tree_desc *desc)); 175local void scan_tree OF((deflate_state *s, ct_data *tree, int max_code)); 176local void send_tree OF((deflate_state *s, ct_data *tree, int max_code)); 177local int build_bl_tree OF((deflate_state *s)); 178local void send_all_trees OF((deflate_state *s, int lcodes, int dcodes, 179 int blcodes)); 180local void compress_block OF((deflate_state *s, ct_data *ltree, 181 ct_data *dtree)); 182local void set_data_type OF((deflate_state *s)); 183local unsigned bi_reverse OF((unsigned value, int length)); 184local void bi_windup OF((deflate_state *s)); 185local void bi_flush OF((deflate_state *s)); 186local void copy_block OF((deflate_state *s, charf *buf, unsigned len, 187 int header)); 188 189#ifdef GEN_TREES_H 190local void gen_trees_header OF((void)); 191#endif 192 193#ifndef DEBUG 194# define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len) 195 /* Send a code of the given tree. c and tree must not have side effects */ 196 197#else /* DEBUG */ 198# define send_code(s, c, tree) \ 199 { if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \ 200 send_bits(s, tree[c].Code, tree[c].Len); } 201#endif 202 203/* =========================================================================== 204 * Output a short LSB first on the stream. 205 * IN assertion: there is enough room in pendingBuf. 206 */ 207#define put_short(s, w) { \ 208 put_byte(s, (uch)((w) & 0xff)); \ 209 put_byte(s, (uch)((ush)(w) >> 8)); \ 210} 211 212/* =========================================================================== 213 * Send a value on a given number of bits. 214 * IN assertion: length <= 16 and value fits in length bits. 215 */ 216#ifdef DEBUG 217local void send_bits OF((deflate_state *s, int value, int length)); 218 219local void send_bits(s, value, length) 220 deflate_state *s; 221 int value; /* value to send */ 222 int length; /* number of bits */ 223{ 224 Tracevv((stderr," l %2d v %4x ", length, value)); 225 Assert(length > 0 && length <= 15, "invalid length"); 226 s->bits_sent += (ulg)length; 227 228 /* If not enough room in bi_buf, use (valid) bits from bi_buf and 229 * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid)) 230 * unused bits in value. 231 */ 232 if (s->bi_valid > (int)Buf_size - length) { 233 s->bi_buf |= (value << s->bi_valid); 234 put_short(s, s->bi_buf); 235 s->bi_buf = (ush)value >> (Buf_size - s->bi_valid); 236 s->bi_valid += length - Buf_size; 237 } else { 238 s->bi_buf |= value << s->bi_valid; 239 s->bi_valid += length; 240 } 241} 242#else /* !DEBUG */ 243 244#define send_bits(s, value, length) \ 245{ int len = length;\ 246 if (s->bi_valid > (int)Buf_size - len) {\ 247 int val = value;\ 248 s->bi_buf |= (val << s->bi_valid);\ 249 put_short(s, s->bi_buf);\ 250 s->bi_buf = (ush)val >> (Buf_size - s->bi_valid);\ 251 s->bi_valid += len - Buf_size;\ 252 } else {\ 253 s->bi_buf |= (value) << s->bi_valid;\ 254 s->bi_valid += len;\ 255 }\ 256} 257#endif /* DEBUG */ 258 259 260/* the arguments must not have side effects */ 261 262/* =========================================================================== 263 * Initialize the various 'constant' tables. 264 */ 265local void tr_static_init() 266{ 267#if defined(GEN_TREES_H) || !defined(STDC) 268 static int static_init_done = 0; 269 int n; /* iterates over tree elements */ 270 int bits; /* bit counter */ 271 int length; /* length value */ 272 int code; /* code value */ 273 int dist; /* distance index */ 274 ush bl_count[MAX_BITS+1]; 275 /* number of codes at each bit length for an optimal tree */ 276 277 if (static_init_done) return; 278 279 /* For some embedded targets, global variables are not initialized: */ 280 static_l_desc.static_tree = static_ltree; 281 static_l_desc.extra_bits = extra_lbits; 282 static_d_desc.static_tree = static_dtree; 283 static_d_desc.extra_bits = extra_dbits; 284 static_bl_desc.extra_bits = extra_blbits; 285 286 /* Initialize the mapping length (0..255) -> length code (0..28) */ 287 length = 0; 288 for (code = 0; code < LENGTH_CODES-1; code++) { 289 base_length[code] = length; 290 for (n = 0; n < (1<<extra_lbits[code]); n++) { 291 _length_code[length++] = (uch)code; 292 } 293 } 294 Assert (length == 256, "tr_static_init: length != 256"); 295 /* Note that the length 255 (match length 258) can be represented 296 * in two different ways: code 284 + 5 bits or code 285, so we 297 * overwrite length_code[255] to use the best encoding: 298 */ 299 _length_code[length-1] = (uch)code; 300 301 /* Initialize the mapping dist (0..32K) -> dist code (0..29) */ 302 dist = 0; 303 for (code = 0 ; code < 16; code++) { 304 base_dist[code] = dist; 305 for (n = 0; n < (1<<extra_dbits[code]); n++) { 306 _dist_code[dist++] = (uch)code; 307 } 308 } 309 Assert (dist == 256, "tr_static_init: dist != 256"); 310 dist >>= 7; /* from now on, all distances are divided by 128 */ 311 for ( ; code < D_CODES; code++) { 312 base_dist[code] = dist << 7; 313 for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) { 314 _dist_code[256 + dist++] = (uch)code; 315 } 316 } 317 Assert (dist == 256, "tr_static_init: 256+dist != 512"); 318 319 /* Construct the codes of the static literal tree */ 320 for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0; 321 n = 0; 322 while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++; 323 while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++; 324 while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++; 325 while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++; 326 /* Codes 286 and 287 do not exist, but we must include them in the 327 * tree construction to get a canonical Huffman tree (longest code 328 * all ones) 329 */ 330 gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count); 331 332 /* The static distance tree is trivial: */ 333 for (n = 0; n < D_CODES; n++) { 334 static_dtree[n].Len = 5; 335 static_dtree[n].Code = bi_reverse((unsigned)n, 5); 336 } 337 static_init_done = 1; 338 339# ifdef GEN_TREES_H 340 gen_trees_header(); 341# endif 342#endif /* defined(GEN_TREES_H) || !defined(STDC) */ 343} 344 345/* =========================================================================== 346 * Genererate the file trees.h describing the static trees. 347 */ 348#ifdef GEN_TREES_H 349# ifndef DEBUG 350# include <stdio.h> 351# endif 352 353# define SEPARATOR(i, last, width) \ 354 ((i) == (last)? "\n};\n\n" : \ 355 ((i) % (width) == (width)-1 ? ",\n" : ", ")) 356 357void gen_trees_header() 358{ 359 FILE *header = fopen("trees.h", "w"); 360 int i; 361 362 Assert (header != NULL, "Can't open trees.h"); 363 fprintf(header, 364 "/* header created automatically with -DGEN_TREES_H */\n\n"); 365 366 fprintf(header, "local const ct_data static_ltree[L_CODES+2] = {\n"); 367 for (i = 0; i < L_CODES+2; i++) { 368 fprintf(header, "{{%3u},{%3u}}%s", static_ltree[i].Code, 369 static_ltree[i].Len, SEPARATOR(i, L_CODES+1, 5)); 370 } 371 372 fprintf(header, "local const ct_data static_dtree[D_CODES] = {\n"); 373 for (i = 0; i < D_CODES; i++) { 374 fprintf(header, "{{%2u},{%2u}}%s", static_dtree[i].Code, 375 static_dtree[i].Len, SEPARATOR(i, D_CODES-1, 5)); 376 } 377 378 fprintf(header, "const uch _dist_code[DIST_CODE_LEN] = {\n"); 379 for (i = 0; i < DIST_CODE_LEN; i++) { 380 fprintf(header, "%2u%s", _dist_code[i], 381 SEPARATOR(i, DIST_CODE_LEN-1, 20)); 382 } 383 384 fprintf(header, "const uch _length_code[MAX_MATCH-MIN_MATCH+1]= {\n"); 385 for (i = 0; i < MAX_MATCH-MIN_MATCH+1; i++) { 386 fprintf(header, "%2u%s", _length_code[i], 387 SEPARATOR(i, MAX_MATCH-MIN_MATCH, 20)); 388 } 389 390 fprintf(header, "local const int base_length[LENGTH_CODES] = {\n"); 391 for (i = 0; i < LENGTH_CODES; i++) { 392 fprintf(header, "%1u%s", base_length[i], 393 SEPARATOR(i, LENGTH_CODES-1, 20)); 394 } 395 396 fprintf(header, "local const int base_dist[D_CODES] = {\n"); 397 for (i = 0; i < D_CODES; i++) { 398 fprintf(header, "%5u%s", base_dist[i], 399 SEPARATOR(i, D_CODES-1, 10)); 400 } 401 402 fclose(header); 403} 404#endif /* GEN_TREES_H */ 405 406/* =========================================================================== 407 * Initialize the tree data structures for a new zlib stream. 408 */ 409void _tr_init(s) 410 deflate_state *s; 411{ 412 tr_static_init(); 413 414 s->l_desc.dyn_tree = s->dyn_ltree; 415 s->l_desc.stat_desc = &static_l_desc; 416 417 s->d_desc.dyn_tree = s->dyn_dtree; 418 s->d_desc.stat_desc = &static_d_desc; 419 420 s->bl_desc.dyn_tree = s->bl_tree; 421 s->bl_desc.stat_desc = &static_bl_desc; 422 423 s->bi_buf = 0; 424 s->bi_valid = 0; 425 s->last_eob_len = 8; /* enough lookahead for inflate */ 426#ifdef DEBUG 427 s->compressed_len = 0L; 428 s->bits_sent = 0L; 429#endif 430 431 /* Initialize the first block of the first file: */ 432 init_block(s); 433} 434 435/* =========================================================================== 436 * Initialize a new block. 437 */ 438local void init_block(s) 439 deflate_state *s; 440{ 441 int n; /* iterates over tree elements */ 442 443 /* Initialize the trees. */ 444 for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0; 445 for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0; 446 for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0; 447 448 s->dyn_ltree[END_BLOCK].Freq = 1; 449 s->opt_len = s->static_len = 0L; 450 s->last_lit = s->matches = 0; 451} 452 453#define SMALLEST 1 454/* Index within the heap array of least frequent node in the Huffman tree */ 455 456 457/* =========================================================================== 458 * Remove the smallest element from the heap and recreate the heap with 459 * one less element. Updates heap and heap_len. 460 */ 461#define pqremove(s, tree, top) \ 462{\ 463 top = s->heap[SMALLEST]; \ 464 s->heap[SMALLEST] = s->heap[s->heap_len--]; \ 465 pqdownheap(s, tree, SMALLEST); \ 466} 467 468/* =========================================================================== 469 * Compares to subtrees, using the tree depth as tie breaker when 470 * the subtrees have equal frequency. This minimizes the worst case length. 471 */ 472#define smaller(tree, n, m, depth) \ 473 (tree[n].Freq < tree[m].Freq || \ 474 (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m])) 475 476/* =========================================================================== 477 * Restore the heap property by moving down the tree starting at node k, 478 * exchanging a node with the smallest of its two sons if necessary, stopping 479 * when the heap property is re-established (each father smaller than its 480 * two sons). 481 */ 482local void pqdownheap(s, tree, k) 483 deflate_state *s; 484 ct_data *tree; /* the tree to restore */ 485 int k; /* node to move down */ 486{ 487 int v = s->heap[k]; 488 int j = k << 1; /* left son of k */ 489 while (j <= s->heap_len) { 490 /* Set j to the smallest of the two sons: */ 491 if (j < s->heap_len && 492 smaller(tree, s->heap[j+1], s->heap[j], s->depth)) { 493 j++; 494 } 495 /* Exit if v is smaller than both sons */ 496 if (smaller(tree, v, s->heap[j], s->depth)) break; 497 498 /* Exchange v with the smallest son */ 499 s->heap[k] = s->heap[j]; k = j; 500 501 /* And continue down the tree, setting j to the left son of k */ 502 j <<= 1; 503 } 504 s->heap[k] = v; 505} 506 507/* =========================================================================== 508 * Compute the optimal bit lengths for a tree and update the total bit length 509 * for the current block. 510 * IN assertion: the fields freq and dad are set, heap[heap_max] and 511 * above are the tree nodes sorted by increasing frequency. 512 * OUT assertions: the field len is set to the optimal bit length, the 513 * array bl_count contains the frequencies for each bit length. 514 * The length opt_len is updated; static_len is also updated if stree is 515 * not null. 516 */ 517local void gen_bitlen(s, desc) 518 deflate_state *s; 519 tree_desc *desc; /* the tree descriptor */ 520{ 521 ct_data *tree = desc->dyn_tree; 522 int max_code = desc->max_code; 523 const ct_data *stree = desc->stat_desc->static_tree; 524 const intf *extra = desc->stat_desc->extra_bits; 525 int base = desc->stat_desc->extra_base; 526 int max_length = desc->stat_desc->max_length; 527 int h; /* heap index */ 528 int n, m; /* iterate over the tree elements */ 529 int bits; /* bit length */ 530 int xbits; /* extra bits */ 531 ush f; /* frequency */ 532 int overflow = 0; /* number of elements with bit length too large */ 533 534 for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0; 535 536 /* In a first pass, compute the optimal bit lengths (which may 537 * overflow in the case of the bit length tree). 538 */ 539 tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */ 540 541 for (h = s->heap_max+1; h < HEAP_SIZE; h++) { 542 n = s->heap[h]; 543 bits = tree[tree[n].Dad].Len + 1; 544 if (bits > max_length) bits = max_length, overflow++; 545 tree[n].Len = (ush)bits; 546 /* We overwrite tree[n].Dad which is no longer needed */ 547 548 if (n > max_code) continue; /* not a leaf node */ 549 550 s->bl_count[bits]++; 551 xbits = 0; 552 if (n >= base) xbits = extra[n-base]; 553 f = tree[n].Freq; 554 s->opt_len += (ulg)f * (bits + xbits); 555 if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits); 556 } 557 if (overflow == 0) return; 558 559 Trace((stderr,"\nbit length overflow\n")); 560 /* This happens for example on obj2 and pic of the Calgary corpus */ 561 562 /* Find the first bit length which could increase: */ 563 do { 564 bits = max_length-1; 565 while (s->bl_count[bits] == 0) bits--; 566 s->bl_count[bits]--; /* move one leaf down the tree */ 567 s->bl_count[bits+1] += 2; /* move one overflow item as its brother */ 568 s->bl_count[max_length]--; 569 /* The brother of the overflow item also moves one step up, 570 * but this does not affect bl_count[max_length] 571 */ 572 overflow -= 2; 573 } while (overflow > 0); 574 575 /* Now recompute all bit lengths, scanning in increasing frequency. 576 * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all 577 * lengths instead of fixing only the wrong ones. This idea is taken 578 * from 'ar' written by Haruhiko Okumura.) 579 */ 580 for (bits = max_length; bits != 0; bits--) { 581 n = s->bl_count[bits]; 582 while (n != 0) { 583 m = s->heap[--h]; 584 if (m > max_code) continue; 585 if ((unsigned) tree[m].Len != (unsigned) bits) { 586 Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits)); 587 s->opt_len += ((long)bits - (long)tree[m].Len) 588 *(long)tree[m].Freq; 589 tree[m].Len = (ush)bits; 590 } 591 n--; 592 } 593 } 594} 595 596/* =========================================================================== 597 * Generate the codes for a given tree and bit counts (which need not be 598 * optimal). 599 * IN assertion: the array bl_count contains the bit length statistics for 600 * the given tree and the field len is set for all tree elements. 601 * OUT assertion: the field code is set for all tree elements of non 602 * zero code length. 603 */ 604local void gen_codes (tree, max_code, bl_count) 605 ct_data *tree; /* the tree to decorate */ 606 int max_code; /* largest code with non zero frequency */ 607 ushf *bl_count; /* number of codes at each bit length */ 608{ 609 ush next_code[MAX_BITS+1]; /* next code value for each bit length */ 610 ush code = 0; /* running code value */ 611 int bits; /* bit index */ 612 int n; /* code index */ 613 614 /* The distribution counts are first used to generate the code values 615 * without bit reversal. 616 */ 617 for (bits = 1; bits <= MAX_BITS; bits++) { 618 next_code[bits] = code = (code + bl_count[bits-1]) << 1; 619 } 620 /* Check that the bit counts in bl_count are consistent. The last code 621 * must be all ones. 622 */ 623 Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1, 624 "inconsistent bit counts"); 625 Tracev((stderr,"\ngen_codes: max_code %d ", max_code)); 626 627 for (n = 0; n <= max_code; n++) { 628 int len = tree[n].Len; 629 if (len == 0) continue; 630 /* Now reverse the bits */ 631 tree[n].Code = bi_reverse(next_code[len]++, len); 632 633 Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ", 634 n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1)); 635 } 636} 637 638/* =========================================================================== 639 * Construct one Huffman tree and assigns the code bit strings and lengths. 640 * Update the total bit length for the current block. 641 * IN assertion: the field freq is set for all tree elements. 642 * OUT assertions: the fields len and code are set to the optimal bit length 643 * and corresponding code. The length opt_len is updated; static_len is 644 * also updated if stree is not null. The field max_code is set. 645 */ 646local void build_tree(s, desc) 647 deflate_state *s; 648 tree_desc *desc; /* the tree descriptor */ 649{ 650 ct_data *tree = desc->dyn_tree; 651 const ct_data *stree = desc->stat_desc->static_tree; 652 int elems = desc->stat_desc->elems; 653 int n, m; /* iterate over heap elements */ 654 int max_code = -1; /* largest code with non zero frequency */ 655 int node; /* new node being created */ 656 657 /* Construct the initial heap, with least frequent element in 658 * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1]. 659 * heap[0] is not used. 660 */ 661 s->heap_len = 0, s->heap_max = HEAP_SIZE; 662 663 for (n = 0; n < elems; n++) { 664 if (tree[n].Freq != 0) { 665 s->heap[++(s->heap_len)] = max_code = n; 666 s->depth[n] = 0; 667 } else { 668 tree[n].Len = 0; 669 } 670 } 671 672 /* The pkzip format requires that at least one distance code exists, 673 * and that at least one bit should be sent even if there is only one 674 * possible code. So to avoid special checks later on we force at least 675 * two codes of non zero frequency. 676 */ 677 while (s->heap_len < 2) { 678 node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0); 679 tree[node].Freq = 1; 680 s->depth[node] = 0; 681 s->opt_len--; if (stree) s->static_len -= stree[node].Len; 682 /* node is 0 or 1 so it does not have extra bits */ 683 } 684 desc->max_code = max_code; 685 686 /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree, 687 * establish sub-heaps of increasing lengths: 688 */ 689 for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, n); 690 691 /* Construct the Huffman tree by repeatedly combining the least two 692 * frequent nodes. 693 */ 694 node = elems; /* next internal node of the tree */ 695 do { 696 pqremove(s, tree, n); /* n = node of least frequency */ 697 m = s->heap[SMALLEST]; /* m = node of next least frequency */ 698 699 s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */ 700 s->heap[--(s->heap_max)] = m; 701 702 /* Create a new node father of n and m */ 703 tree[node].Freq = tree[n].Freq + tree[m].Freq; 704 s->depth[node] = (uch)((s->depth[n] >= s->depth[m] ? 705 s->depth[n] : s->depth[m]) + 1); 706 tree[n].Dad = tree[m].Dad = (ush)node; 707#ifdef DUMP_BL_TREE 708 if (tree == s->bl_tree) { 709 fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)", 710 node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq); 711 } 712#endif 713 /* and insert the new node in the heap */ 714 s->heap[SMALLEST] = node++; 715 pqdownheap(s, tree, SMALLEST); 716 717 } while (s->heap_len >= 2); 718 719 s->heap[--(s->heap_max)] = s->heap[SMALLEST]; 720 721 /* At this point, the fields freq and dad are set. We can now 722 * generate the bit lengths. 723 */ 724 gen_bitlen(s, (tree_desc *)desc); 725 726 /* The field len is now set, we can generate the bit codes */ 727 gen_codes ((ct_data *)tree, max_code, s->bl_count); 728} 729 730/* =========================================================================== 731 * Scan a literal or distance tree to determine the frequencies of the codes 732 * in the bit length tree. 733 */ 734local void scan_tree (s, tree, max_code) 735 deflate_state *s; 736 ct_data *tree; /* the tree to be scanned */ 737 int max_code; /* and its largest code of non zero frequency */ 738{ 739 int n; /* iterates over all tree elements */ 740 int prevlen = -1; /* last emitted length */ 741 int curlen; /* length of current code */ 742 int nextlen = tree[0].Len; /* length of next code */ 743 int count = 0; /* repeat count of the current code */ 744 int max_count = 7; /* max repeat count */ 745 int min_count = 4; /* min repeat count */ 746 747 if (nextlen == 0) max_count = 138, min_count = 3; 748 tree[max_code+1].Len = (ush)0xffff; /* guard */ 749 750 for (n = 0; n <= max_code; n++) { 751 curlen = nextlen; nextlen = tree[n+1].Len; 752 if (++count < max_count && curlen == nextlen) { 753 continue; 754 } else if (count < min_count) { 755 s->bl_tree[curlen].Freq += count; 756 } else if (curlen != 0) { 757 if (curlen != prevlen) s->bl_tree[curlen].Freq++; 758 s->bl_tree[REP_3_6].Freq++; 759 } else if (count <= 10) { 760 s->bl_tree[REPZ_3_10].Freq++; 761 } else { 762 s->bl_tree[REPZ_11_138].Freq++; 763 } 764 count = 0; prevlen = curlen; 765 if (nextlen == 0) { 766 max_count = 138, min_count = 3; 767 } else if (curlen == nextlen) { 768 max_count = 6, min_count = 3; 769 } else { 770 max_count = 7, min_count = 4; 771 } 772 } 773} 774 775/* =========================================================================== 776 * Send a literal or distance tree in compressed form, using the codes in 777 * bl_tree. 778 */ 779local void send_tree (s, tree, max_code) 780 deflate_state *s; 781 ct_data *tree; /* the tree to be scanned */ 782 int max_code; /* and its largest code of non zero frequency */ 783{ 784 int n; /* iterates over all tree elements */ 785 int prevlen = -1; /* last emitted length */ 786 int curlen; /* length of current code */ 787 int nextlen = tree[0].Len; /* length of next code */ 788 int count = 0; /* repeat count of the current code */ 789 int max_count = 7; /* max repeat count */ 790 int min_count = 4; /* min repeat count */ 791 792 /* tree[max_code+1].Len = -1; */ /* guard already set */ 793 if (nextlen == 0) max_count = 138, min_count = 3; 794 795 for (n = 0; n <= max_code; n++) { 796 curlen = nextlen; nextlen = tree[n+1].Len; 797 if (++count < max_count && curlen == nextlen) { 798 continue; 799 } else if (count < min_count) { 800 do { send_code(s, curlen, s->bl_tree); } while (--count != 0); 801 802 } else if (curlen != 0) { 803 if (curlen != prevlen) { 804 send_code(s, curlen, s->bl_tree); count--; 805 } 806 Assert(count >= 3 && count <= 6, " 3_6?"); 807 send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2); 808 809 } else if (count <= 10) { 810 send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3); 811 812 } else { 813 send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7); 814 } 815 count = 0; prevlen = curlen; 816 if (nextlen == 0) { 817 max_count = 138, min_count = 3; 818 } else if (curlen == nextlen) { 819 max_count = 6, min_count = 3; 820 } else { 821 max_count = 7, min_count = 4; 822 } 823 } 824} 825 826/* =========================================================================== 827 * Construct the Huffman tree for the bit lengths and return the index in 828 * bl_order of the last bit length code to send. 829 */ 830local int build_bl_tree(s) 831 deflate_state *s; 832{ 833 int max_blindex; /* index of last bit length code of non zero freq */ 834 835 /* Determine the bit length frequencies for literal and distance trees */ 836 scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code); 837 scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code); 838 839 /* Build the bit length tree: */ 840 build_tree(s, (tree_desc *)(&(s->bl_desc))); 841 /* opt_len now includes the length of the tree representations, except 842 * the lengths of the bit lengths codes and the 5+5+4 bits for the counts. 843 */ 844 845 /* Determine the number of bit length codes to send. The pkzip format 846 * requires that at least 4 bit length codes be sent. (appnote.txt says 847 * 3 but the actual value used is 4.) 848 */ 849 for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) { 850 if (s->bl_tree[bl_order[max_blindex]].Len != 0) break; 851 } 852 /* Update opt_len to include the bit length tree and counts */ 853 s->opt_len += 3*(max_blindex+1) + 5+5+4; 854 Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld", 855 s->opt_len, s->static_len)); 856 857 return max_blindex; 858} 859 860/* =========================================================================== 861 * Send the header for a block using dynamic Huffman trees: the counts, the 862 * lengths of the bit length codes, the literal tree and the distance tree. 863 * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4. 864 */ 865local void send_all_trees(s, lcodes, dcodes, blcodes) 866 deflate_state *s; 867 int lcodes, dcodes, blcodes; /* number of codes for each tree */ 868{ 869 int rank; /* index in bl_order */ 870 871 Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes"); 872 Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES, 873 "too many codes"); 874 Tracev((stderr, "\nbl counts: ")); 875 send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */ 876 send_bits(s, dcodes-1, 5); 877 send_bits(s, blcodes-4, 4); /* not -3 as stated in appnote.txt */ 878 for (rank = 0; rank < blcodes; rank++) { 879 Tracev((stderr, "\nbl code %2d ", bl_order[rank])); 880 send_bits(s, s->bl_tree[bl_order[rank]].Len, 3); 881 } 882 Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent)); 883 884 send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */ 885 Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent)); 886 887 send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */ 888 Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent)); 889} 890 891/* =========================================================================== 892 * Send a stored block 893 */ 894void _tr_stored_block(s, buf, stored_len, eof) 895 deflate_state *s; 896 charf *buf; /* input block */ 897 ulg stored_len; /* length of input block */ 898 int eof; /* true if this is the last block for a file */ 899{ 900 send_bits(s, (STORED_BLOCK<<1)+eof, 3); /* send block type */ 901#ifdef DEBUG 902 s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L; 903 s->compressed_len += (stored_len + 4) << 3; 904#endif 905 copy_block(s, buf, (unsigned)stored_len, 1); /* with header */ 906} 907 908/* =========================================================================== 909 * Send one empty static block to give enough lookahead for inflate. 910 * This takes 10 bits, of which 7 may remain in the bit buffer. 911 * The current inflate code requires 9 bits of lookahead. If the 912 * last two codes for the previous block (real code plus EOB) were coded 913 * on 5 bits or less, inflate may have only 5+3 bits of lookahead to decode 914 * the last real code. In this case we send two empty static blocks instead 915 * of one. (There are no problems if the previous block is stored or fixed.) 916 * To simplify the code, we assume the worst case of last real code encoded 917 * on one bit only. 918 */ 919void _tr_align(s) 920 deflate_state *s; 921{ 922 send_bits(s, STATIC_TREES<<1, 3); 923 send_code(s, END_BLOCK, static_ltree); 924#ifdef DEBUG 925 s->compressed_len += 10L; /* 3 for block type, 7 for EOB */ 926#endif 927 bi_flush(s); 928 /* Of the 10 bits for the empty block, we have already sent 929 * (10 - bi_valid) bits. The lookahead for the last real code (before 930 * the EOB of the previous block) was thus at least one plus the length 931 * of the EOB plus what we have just sent of the empty static block. 932 */ 933 if (1 + s->last_eob_len + 10 - s->bi_valid < 9) { 934 send_bits(s, STATIC_TREES<<1, 3); 935 send_code(s, END_BLOCK, static_ltree); 936#ifdef DEBUG 937 s->compressed_len += 10L; 938#endif 939 bi_flush(s); 940 } 941 s->last_eob_len = 7; 942} 943 944/* =========================================================================== 945 * Determine the best encoding for the current block: dynamic trees, static 946 * trees or store, and output the encoded block to the zip file. 947 */ 948void _tr_flush_block(s, buf, stored_len, eof) 949 deflate_state *s; 950 charf *buf; /* input block, or NULL if too old */ 951 ulg stored_len; /* length of input block */ 952 int eof; /* true if this is the last block for a file */ 953{ 954 ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */ 955 int max_blindex = 0; /* index of last bit length code of non zero freq */ 956 957 /* Build the Huffman trees unless a stored block is forced */ 958 if (s->level > 0) { 959 960 /* Check if the file is binary or text */ 961 if (stored_len > 0 && s->strm->data_type == Z_UNKNOWN) 962 set_data_type(s); 963 964 /* Construct the literal and distance trees */ 965 build_tree(s, (tree_desc *)(&(s->l_desc))); 966 Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len, 967 s->static_len)); 968 969 build_tree(s, (tree_desc *)(&(s->d_desc))); 970 Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len, 971 s->static_len)); 972 /* At this point, opt_len and static_len are the total bit lengths of 973 * the compressed block data, excluding the tree representations. 974 */ 975 976 /* Build the bit length tree for the above two trees, and get the index 977 * in bl_order of the last bit length code to send. 978 */ 979 max_blindex = build_bl_tree(s); 980 981 /* Determine the best encoding. Compute the block lengths in bytes. */ 982 opt_lenb = (s->opt_len+3+7)>>3; 983 static_lenb = (s->static_len+3+7)>>3; 984 985 Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ", 986 opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len, 987 s->last_lit)); 988 989 if (static_lenb <= opt_lenb) opt_lenb = static_lenb; 990 991 } else { 992 Assert(buf != (char*)0, "lost buf"); 993 opt_lenb = static_lenb = stored_len + 5; /* force a stored block */ 994 } 995 996#ifdef FORCE_STORED 997 if (buf != (char*)0) { /* force stored block */ 998#else 999 if (stored_len+4 <= opt_lenb && buf != (char*)0) { 1000 /* 4: two words for the lengths */ 1001#endif 1002 /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE. 1003 * Otherwise we can't have processed more than WSIZE input bytes since 1004 * the last block flush, because compression would have been 1005 * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to 1006 * transform a block into a stored block. 1007 */ 1008 _tr_stored_block(s, buf, stored_len, eof); 1009 1010#ifdef FORCE_STATIC 1011 } else if (static_lenb >= 0) { /* force static trees */ 1012#else 1013 } else if (s->strategy == Z_FIXED || static_lenb == opt_lenb) { 1014#endif 1015 send_bits(s, (STATIC_TREES<<1)+eof, 3); 1016 compress_block(s, (ct_data *)static_ltree, (ct_data *)static_dtree); 1017#ifdef DEBUG 1018 s->compressed_len += 3 + s->static_len; 1019#endif 1020 } else { 1021 send_bits(s, (DYN_TREES<<1)+eof, 3); 1022 send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1, 1023 max_blindex+1); 1024 compress_block(s, (ct_data *)s->dyn_ltree, (ct_data *)s->dyn_dtree); 1025#ifdef DEBUG 1026 s->compressed_len += 3 + s->opt_len; 1027#endif 1028 } 1029 Assert (s->compressed_len == s->bits_sent, "bad compressed size"); 1030 /* The above check is made mod 2^32, for files larger than 512 MB 1031 * and uLong implemented on 32 bits. 1032 */ 1033 init_block(s); 1034 1035 if (eof) { 1036 bi_windup(s); 1037#ifdef DEBUG 1038 s->compressed_len += 7; /* align on byte boundary */ 1039#endif 1040 } 1041 Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3, 1042 s->compressed_len-7*eof)); 1043} 1044 1045/* =========================================================================== 1046 * Save the match info and tally the frequency counts. Return true if 1047 * the current block must be flushed. 1048 */ 1049int _tr_tally (s, dist, lc) 1050 deflate_state *s; 1051 unsigned dist; /* distance of matched string */ 1052 unsigned lc; /* match length-MIN_MATCH or unmatched char (if dist==0) */ 1053{ 1054 s->d_buf[s->last_lit] = (ush)dist; 1055 s->l_buf[s->last_lit++] = (uch)lc; 1056 if (dist == 0) { 1057 /* lc is the unmatched char */ 1058 s->dyn_ltree[lc].Freq++; 1059 } else { 1060 s->matches++; 1061 /* Here, lc is the match length - MIN_MATCH */ 1062 dist--; /* dist = match distance - 1 */ 1063 Assert((ush)dist < (ush)MAX_DIST(s) && 1064 (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) && 1065 (ush)d_code(dist) < (ush)D_CODES, "_tr_tally: bad match"); 1066 1067 s->dyn_ltree[_length_code[lc]+LITERALS+1].Freq++; 1068 s->dyn_dtree[d_code(dist)].Freq++; 1069 } 1070 1071#ifdef TRUNCATE_BLOCK 1072 /* Try to guess if it is profitable to stop the current block here */ 1073 if ((s->last_lit & 0x1fff) == 0 && s->level > 2) { 1074 /* Compute an upper bound for the compressed length */ 1075 ulg out_length = (ulg)s->last_lit*8L; 1076 ulg in_length = (ulg)((long)s->strstart - s->block_start); 1077 int dcode; 1078 for (dcode = 0; dcode < D_CODES; dcode++) { 1079 out_length += (ulg)s->dyn_dtree[dcode].Freq * 1080 (5L+extra_dbits[dcode]); 1081 } 1082 out_length >>= 3; 1083 Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ", 1084 s->last_lit, in_length, out_length, 1085 100L - out_length*100L/in_length)); 1086 if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1; 1087 } 1088#endif 1089 return (s->last_lit == s->lit_bufsize-1); 1090 /* We avoid equality with lit_bufsize because of wraparound at 64K 1091 * on 16 bit machines and because stored blocks are restricted to 1092 * 64K-1 bytes. 1093 */ 1094} 1095 1096/* =========================================================================== 1097 * Send the block data compressed using the given Huffman trees 1098 */ 1099local void compress_block(s, ltree, dtree) 1100 deflate_state *s; 1101 ct_data *ltree; /* literal tree */ 1102 ct_data *dtree; /* distance tree */ 1103{ 1104 unsigned dist; /* distance of matched string */ 1105 int lc; /* match length or unmatched char (if dist == 0) */ 1106 unsigned lx = 0; /* running index in l_buf */ 1107 unsigned code; /* the code to send */ 1108 int extra; /* number of extra bits to send */ 1109 1110 if (s->last_lit != 0) do { 1111 dist = s->d_buf[lx]; 1112 lc = s->l_buf[lx++]; 1113 if (dist == 0) { 1114 send_code(s, lc, ltree); /* send a literal byte */ 1115 Tracecv(isgraph(lc), (stderr," '%c' ", lc)); 1116 } else { 1117 /* Here, lc is the match length - MIN_MATCH */ 1118 code = _length_code[lc]; 1119 send_code(s, code+LITERALS+1, ltree); /* send the length code */ 1120 extra = extra_lbits[code]; 1121 if (extra != 0) { 1122 lc -= base_length[code]; 1123 send_bits(s, lc, extra); /* send the extra length bits */ 1124 } 1125 dist--; /* dist is now the match distance - 1 */ 1126 code = d_code(dist); 1127 Assert (code < D_CODES, "bad d_code"); 1128 1129 send_code(s, code, dtree); /* send the distance code */ 1130 extra = extra_dbits[code]; 1131 if (extra != 0) { 1132 dist -= base_dist[code]; 1133 send_bits(s, dist, extra); /* send the extra distance bits */ 1134 } 1135 } /* literal or match pair ? */ 1136 1137 /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */ 1138 Assert((uInt)(s->pending) < s->lit_bufsize + 2*lx, 1139 "pendingBuf overflow"); 1140 1141 } while (lx < s->last_lit); 1142 1143 send_code(s, END_BLOCK, ltree); 1144 s->last_eob_len = ltree[END_BLOCK].Len; 1145} 1146 1147/* =========================================================================== 1148 * Set the data type to BINARY or TEXT, using a crude approximation: 1149 * set it to Z_TEXT if all symbols are either printable characters (33 to 255) 1150 * or white spaces (9 to 13, or 32); or set it to Z_BINARY otherwise. 1151 * IN assertion: the fields Freq of dyn_ltree are set. 1152 */ 1153local void set_data_type(s) 1154 deflate_state *s; 1155{ 1156 int n; 1157 1158 for (n = 0; n < 9; n++) 1159 if (s->dyn_ltree[n].Freq != 0) 1160 break; 1161 if (n == 9) 1162 for (n = 14; n < 32; n++) 1163 if (s->dyn_ltree[n].Freq != 0) 1164 break; 1165 s->strm->data_type = (n == 32) ? Z_TEXT : Z_BINARY; 1166} 1167 1168/* =========================================================================== 1169 * Reverse the first len bits of a code, using straightforward code (a faster 1170 * method would use a table) 1171 * IN assertion: 1 <= len <= 15 1172 */ 1173local unsigned bi_reverse(code, len) 1174 unsigned code; /* the value to invert */ 1175 int len; /* its bit length */ 1176{ 1177 register unsigned res = 0; 1178 do { 1179 res |= code & 1; 1180 code >>= 1, res <<= 1; 1181 } while (--len > 0); 1182 return res >> 1; 1183} 1184 1185/* =========================================================================== 1186 * Flush the bit buffer, keeping at most 7 bits in it. 1187 */ 1188local void bi_flush(s) 1189 deflate_state *s; 1190{ 1191 if (s->bi_valid == 16) { 1192 put_short(s, s->bi_buf); 1193 s->bi_buf = 0; 1194 s->bi_valid = 0; 1195 } else if (s->bi_valid >= 8) { 1196 put_byte(s, (Byte)s->bi_buf); 1197 s->bi_buf >>= 8; 1198 s->bi_valid -= 8; 1199 } 1200} 1201 1202/* =========================================================================== 1203 * Flush the bit buffer and align the output on a byte boundary 1204 */ 1205local void bi_windup(s) 1206 deflate_state *s; 1207{ 1208 if (s->bi_valid > 8) { 1209 put_short(s, s->bi_buf); 1210 } else if (s->bi_valid > 0) { 1211 put_byte(s, (Byte)s->bi_buf); 1212 } 1213 s->bi_buf = 0; 1214 s->bi_valid = 0; 1215#ifdef DEBUG 1216 s->bits_sent = (s->bits_sent+7) & ~7; 1217#endif 1218} 1219 1220/* =========================================================================== 1221 * Copy a stored block, storing first the length and its 1222 * one's complement if requested. 1223 */ 1224local void copy_block(s, buf, len, header) 1225 deflate_state *s; 1226 charf *buf; /* the input data */ 1227 unsigned len; /* its length */ 1228 int header; /* true if block header must be written */ 1229{ 1230 bi_windup(s); /* align on byte boundary */ 1231 s->last_eob_len = 8; /* enough lookahead for inflate */ 1232 1233 if (header) { 1234 put_short(s, (ush)len); 1235 put_short(s, (ush)~len); 1236#ifdef DEBUG 1237 s->bits_sent += 2*16; 1238#endif 1239 } 1240#ifdef DEBUG 1241 s->bits_sent += (ulg)len<<3; 1242#endif 1243 while (len--) { 1244 put_byte(s, *buf++); 1245 } 1246} 1247