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