1 : /* trees.c -- output deflated data using Huffman coding
2 : * Copyright (C) 1995-2010 Jean-loup Gailly
3 : * detect_data_type() function provided freely by Cosmin Truta, 2006
4 : * For conditions of distribution and use, see copyright notice in zlib.h
5 : */
6 :
7 : /*
8 : * ALGORITHM
9 : *
10 : * The "deflation" process uses several Huffman trees. The more
11 : * common source values are represented by shorter bit sequences.
12 : *
13 : * Each code tree is stored in a compressed form which is itself
14 : * a Huffman encoding of the lengths of all the code strings (in
15 : * ascending order by source values). The actual code strings are
16 : * reconstructed from the lengths in the inflate process, as described
17 : * in the deflate specification.
18 : *
19 : * REFERENCES
20 : *
21 : * Deutsch, L.P.,"'Deflate' Compressed Data Format Specification".
22 : * Available in ftp.uu.net:/pub/archiving/zip/doc/deflate-1.1.doc
23 : *
24 : * Storer, James A.
25 : * Data Compression: Methods and Theory, pp. 49-50.
26 : * Computer Science Press, 1988. ISBN 0-7167-8156-5.
27 : *
28 : * Sedgewick, R.
29 : * Algorithms, p290.
30 : * Addison-Wesley, 1983. ISBN 0-201-06672-6.
31 : */
32 :
33 : /* @(#) $Id$ */
34 :
35 : /* #define GEN_TREES_H */
36 :
37 : #include "deflate.h"
38 :
39 : #ifdef DEBUG
40 : # include <ctype.h>
41 : #endif
42 :
43 : /* ===========================================================================
44 : * Constants
45 : */
46 :
47 : #define MAX_BL_BITS 7
48 : /* Bit length codes must not exceed MAX_BL_BITS bits */
49 :
50 : #define END_BLOCK 256
51 : /* end of block literal code */
52 :
53 : #define REP_3_6 16
54 : /* repeat previous bit length 3-6 times (2 bits of repeat count) */
55 :
56 : #define REPZ_3_10 17
57 : /* repeat a zero length 3-10 times (3 bits of repeat count) */
58 :
59 : #define REPZ_11_138 18
60 : /* repeat a zero length 11-138 times (7 bits of repeat count) */
61 :
62 : local const int extra_lbits[LENGTH_CODES] /* extra bits for each length code */
63 : = {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};
64 :
65 : local const int extra_dbits[D_CODES] /* extra bits for each distance code */
66 : = {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};
67 :
68 : local const int extra_blbits[BL_CODES]/* extra bits for each bit length code */
69 : = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7};
70 :
71 : local const uch bl_order[BL_CODES]
72 : = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15};
73 : /* The lengths of the bit length codes are sent in order of decreasing
74 : * probability, to avoid transmitting the lengths for unused bit length codes.
75 : */
76 :
77 : #define Buf_size (8 * 2*sizeof(char))
78 : /* Number of bits used within bi_buf. (bi_buf might be implemented on
79 : * more than 16 bits on some systems.)
80 : */
81 :
82 : /* ===========================================================================
83 : * Local data. These are initialized only once.
84 : */
85 :
86 : #define DIST_CODE_LEN 512 /* see definition of array dist_code below */
87 :
88 : #if defined(GEN_TREES_H) || !defined(STDC)
89 : /* non ANSI compilers may not accept trees.h */
90 :
91 : local ct_data static_ltree[L_CODES+2];
92 : /* The static literal tree. Since the bit lengths are imposed, there is no
93 : * need for the L_CODES extra codes used during heap construction. However
94 : * The codes 286 and 287 are needed to build a canonical tree (see _tr_init
95 : * below).
96 : */
97 :
98 : local ct_data static_dtree[D_CODES];
99 : /* The static distance tree. (Actually a trivial tree since all codes use
100 : * 5 bits.)
101 : */
102 :
103 : uch _dist_code[DIST_CODE_LEN];
104 : /* Distance codes. The first 256 values correspond to the distances
105 : * 3 .. 258, the last 256 values correspond to the top 8 bits of
106 : * the 15 bit distances.
107 : */
108 :
109 : uch _length_code[MAX_MATCH-MIN_MATCH+1];
110 : /* length code for each normalized match length (0 == MIN_MATCH) */
111 :
112 : local int base_length[LENGTH_CODES];
113 : /* First normalized length for each code (0 = MIN_MATCH) */
114 :
115 : local int base_dist[D_CODES];
116 : /* First normalized distance for each code (0 = distance of 1) */
117 :
118 : #else
119 : # include "trees.h"
120 : #endif /* GEN_TREES_H */
121 :
122 : struct static_tree_desc_s {
123 : const ct_data *static_tree; /* static tree or NULL */
124 : const intf *extra_bits; /* extra bits for each code or NULL */
125 : int extra_base; /* base index for extra_bits */
126 : int elems; /* max number of elements in the tree */
127 : int max_length; /* max bit length for the codes */
128 : };
129 :
130 : local static_tree_desc static_l_desc =
131 : {static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS};
132 :
133 : local static_tree_desc static_d_desc =
134 : {static_dtree, extra_dbits, 0, D_CODES, MAX_BITS};
135 :
136 : local static_tree_desc static_bl_desc =
137 : {(const ct_data *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS};
138 :
139 : /* ===========================================================================
140 : * Local (static) routines in this file.
141 : */
142 :
143 : local void tr_static_init OF((void));
144 : local void init_block OF((deflate_state *s));
145 : local void pqdownheap OF((deflate_state *s, ct_data *tree, int k));
146 : local void gen_bitlen OF((deflate_state *s, tree_desc *desc));
147 : local void gen_codes OF((ct_data *tree, int max_code, ushf *bl_count));
148 : local void build_tree OF((deflate_state *s, tree_desc *desc));
149 : local void scan_tree OF((deflate_state *s, ct_data *tree, int max_code));
150 : local void send_tree OF((deflate_state *s, ct_data *tree, int max_code));
151 : local int build_bl_tree OF((deflate_state *s));
152 : local void send_all_trees OF((deflate_state *s, int lcodes, int dcodes,
153 : int blcodes));
154 : local void compress_block OF((deflate_state *s, ct_data *ltree,
155 : ct_data *dtree));
156 : local int detect_data_type OF((deflate_state *s));
157 : local unsigned bi_reverse OF((unsigned value, int length));
158 : local void bi_windup OF((deflate_state *s));
159 : local void bi_flush OF((deflate_state *s));
160 : local void copy_block OF((deflate_state *s, charf *buf, unsigned len,
161 : int header));
162 :
163 : #ifdef GEN_TREES_H
164 : local void gen_trees_header OF((void));
165 : #endif
166 :
167 : #ifndef DEBUG
168 : # define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len)
169 : /* Send a code of the given tree. c and tree must not have side effects */
170 :
171 : #else /* DEBUG */
172 : # define send_code(s, c, tree) \
173 : { if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \
174 : send_bits(s, tree[c].Code, tree[c].Len); }
175 : #endif
176 :
177 : /* ===========================================================================
178 : * Output a short LSB first on the stream.
179 : * IN assertion: there is enough room in pendingBuf.
180 : */
181 : #define put_short(s, w) { \
182 : put_byte(s, (uch)((w) & 0xff)); \
183 : put_byte(s, (uch)((ush)(w) >> 8)); \
184 : }
185 :
186 : /* ===========================================================================
187 : * Send a value on a given number of bits.
188 : * IN assertion: length <= 16 and value fits in length bits.
189 : */
190 : #ifdef DEBUG
191 : local void send_bits OF((deflate_state *s, int value, int length));
192 :
193 : local void send_bits(s, value, length)
194 : deflate_state *s;
195 : int value; /* value to send */
196 : int length; /* number of bits */
197 : {
198 : Tracevv((stderr," l %2d v %4x ", length, value));
199 : Assert(length > 0 && length <= 15, "invalid length");
200 : s->bits_sent += (ulg)length;
201 :
202 : /* If not enough room in bi_buf, use (valid) bits from bi_buf and
203 : * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid))
204 : * unused bits in value.
205 : */
206 : if (s->bi_valid > (int)Buf_size - length) {
207 : s->bi_buf |= (ush)value << s->bi_valid;
208 : put_short(s, s->bi_buf);
209 : s->bi_buf = (ush)value >> (Buf_size - s->bi_valid);
210 : s->bi_valid += length - Buf_size;
211 : } else {
212 : s->bi_buf |= (ush)value << s->bi_valid;
213 : s->bi_valid += length;
214 : }
215 : }
216 : #else /* !DEBUG */
217 :
218 : #define send_bits(s, value, length) \
219 : { int len = length;\
220 : if (s->bi_valid > (int)Buf_size - len) {\
221 : int val = value;\
222 : s->bi_buf |= (ush)val << s->bi_valid;\
223 : put_short(s, s->bi_buf);\
224 : s->bi_buf = (ush)val >> (Buf_size - s->bi_valid);\
225 : s->bi_valid += len - Buf_size;\
226 : } else {\
227 : s->bi_buf |= (ush)(value) << s->bi_valid;\
228 : s->bi_valid += len;\
229 : }\
230 : }
231 : #endif /* DEBUG */
232 :
233 :
234 : /* the arguments must not have side effects */
235 :
236 : /* ===========================================================================
237 : * Initialize the various 'constant' tables.
238 : */
239 5217 : local void tr_static_init()
240 : {
241 : #if defined(GEN_TREES_H) || !defined(STDC)
242 : static int static_init_done = 0;
243 : int n; /* iterates over tree elements */
244 : int bits; /* bit counter */
245 : int length; /* length value */
246 : int code; /* code value */
247 : int dist; /* distance index */
248 : ush bl_count[MAX_BITS+1];
249 : /* number of codes at each bit length for an optimal tree */
250 :
251 : if (static_init_done) return;
252 :
253 : /* For some embedded targets, global variables are not initialized: */
254 : #ifdef NO_INIT_GLOBAL_POINTERS
255 : static_l_desc.static_tree = static_ltree;
256 : static_l_desc.extra_bits = extra_lbits;
257 : static_d_desc.static_tree = static_dtree;
258 : static_d_desc.extra_bits = extra_dbits;
259 : static_bl_desc.extra_bits = extra_blbits;
260 : #endif
261 :
262 : /* Initialize the mapping length (0..255) -> length code (0..28) */
263 : length = 0;
264 : for (code = 0; code < LENGTH_CODES-1; code++) {
265 : base_length[code] = length;
266 : for (n = 0; n < (1<<extra_lbits[code]); n++) {
267 : _length_code[length++] = (uch)code;
268 : }
269 : }
270 : Assert (length == 256, "tr_static_init: length != 256");
271 : /* Note that the length 255 (match length 258) can be represented
272 : * in two different ways: code 284 + 5 bits or code 285, so we
273 : * overwrite length_code[255] to use the best encoding:
274 : */
275 : _length_code[length-1] = (uch)code;
276 :
277 : /* Initialize the mapping dist (0..32K) -> dist code (0..29) */
278 : dist = 0;
279 : for (code = 0 ; code < 16; code++) {
280 : base_dist[code] = dist;
281 : for (n = 0; n < (1<<extra_dbits[code]); n++) {
282 : _dist_code[dist++] = (uch)code;
283 : }
284 : }
285 : Assert (dist == 256, "tr_static_init: dist != 256");
286 : dist >>= 7; /* from now on, all distances are divided by 128 */
287 : for ( ; code < D_CODES; code++) {
288 : base_dist[code] = dist << 7;
289 : for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) {
290 : _dist_code[256 + dist++] = (uch)code;
291 : }
292 : }
293 : Assert (dist == 256, "tr_static_init: 256+dist != 512");
294 :
295 : /* Construct the codes of the static literal tree */
296 : for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0;
297 : n = 0;
298 : while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++;
299 : while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++;
300 : while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++;
301 : while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++;
302 : /* Codes 286 and 287 do not exist, but we must include them in the
303 : * tree construction to get a canonical Huffman tree (longest code
304 : * all ones)
305 : */
306 : gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count);
307 :
308 : /* The static distance tree is trivial: */
309 : for (n = 0; n < D_CODES; n++) {
310 : static_dtree[n].Len = 5;
311 : static_dtree[n].Code = bi_reverse((unsigned)n, 5);
312 : }
313 : static_init_done = 1;
314 :
315 : # ifdef GEN_TREES_H
316 : gen_trees_header();
317 : # endif
318 : #endif /* defined(GEN_TREES_H) || !defined(STDC) */
319 5217 : }
320 :
321 : /* ===========================================================================
322 : * Genererate the file trees.h describing the static trees.
323 : */
324 : #ifdef GEN_TREES_H
325 : # ifndef DEBUG
326 : # include <stdio.h>
327 : # endif
328 :
329 : # define SEPARATOR(i, last, width) \
330 : ((i) == (last)? "\n};\n\n" : \
331 : ((i) % (width) == (width)-1 ? ",\n" : ", "))
332 :
333 : void gen_trees_header()
334 : {
335 : FILE *header = fopen("trees.h", "w");
336 : int i;
337 :
338 : Assert (header != NULL, "Can't open trees.h");
339 : fprintf(header,
340 : "/* header created automatically with -DGEN_TREES_H */\n\n");
341 :
342 : fprintf(header, "local const ct_data static_ltree[L_CODES+2] = {\n");
343 : for (i = 0; i < L_CODES+2; i++) {
344 : fprintf(header, "{{%3u},{%3u}}%s", static_ltree[i].Code,
345 : static_ltree[i].Len, SEPARATOR(i, L_CODES+1, 5));
346 : }
347 :
348 : fprintf(header, "local const ct_data static_dtree[D_CODES] = {\n");
349 : for (i = 0; i < D_CODES; i++) {
350 : fprintf(header, "{{%2u},{%2u}}%s", static_dtree[i].Code,
351 : static_dtree[i].Len, SEPARATOR(i, D_CODES-1, 5));
352 : }
353 :
354 : fprintf(header, "const uch ZLIB_INTERNAL _dist_code[DIST_CODE_LEN] = {\n");
355 : for (i = 0; i < DIST_CODE_LEN; i++) {
356 : fprintf(header, "%2u%s", _dist_code[i],
357 : SEPARATOR(i, DIST_CODE_LEN-1, 20));
358 : }
359 :
360 : fprintf(header,
361 : "const uch ZLIB_INTERNAL _length_code[MAX_MATCH-MIN_MATCH+1]= {\n");
362 : for (i = 0; i < MAX_MATCH-MIN_MATCH+1; i++) {
363 : fprintf(header, "%2u%s", _length_code[i],
364 : SEPARATOR(i, MAX_MATCH-MIN_MATCH, 20));
365 : }
366 :
367 : fprintf(header, "local const int base_length[LENGTH_CODES] = {\n");
368 : for (i = 0; i < LENGTH_CODES; i++) {
369 : fprintf(header, "%1u%s", base_length[i],
370 : SEPARATOR(i, LENGTH_CODES-1, 20));
371 : }
372 :
373 : fprintf(header, "local const int base_dist[D_CODES] = {\n");
374 : for (i = 0; i < D_CODES; i++) {
375 : fprintf(header, "%5u%s", base_dist[i],
376 : SEPARATOR(i, D_CODES-1, 10));
377 : }
378 :
379 : fclose(header);
380 : }
381 : #endif /* GEN_TREES_H */
382 :
383 : /* ===========================================================================
384 : * Initialize the tree data structures for a new zlib stream.
385 : */
386 5217 : void ZLIB_INTERNAL _tr_init(s)
387 : deflate_state *s;
388 : {
389 5217 : tr_static_init();
390 :
391 5217 : s->l_desc.dyn_tree = s->dyn_ltree;
392 5217 : s->l_desc.stat_desc = &static_l_desc;
393 :
394 5217 : s->d_desc.dyn_tree = s->dyn_dtree;
395 5217 : s->d_desc.stat_desc = &static_d_desc;
396 :
397 5217 : s->bl_desc.dyn_tree = s->bl_tree;
398 5217 : s->bl_desc.stat_desc = &static_bl_desc;
399 :
400 5217 : s->bi_buf = 0;
401 5217 : s->bi_valid = 0;
402 5217 : s->last_eob_len = 8; /* enough lookahead for inflate */
403 : #ifdef DEBUG
404 : s->compressed_len = 0L;
405 : s->bits_sent = 0L;
406 : #endif
407 :
408 : /* Initialize the first block of the first file: */
409 5217 : init_block(s);
410 5217 : }
411 :
412 : /* ===========================================================================
413 : * Initialize a new block.
414 : */
415 12985 : local void init_block(s)
416 : deflate_state *s;
417 : {
418 : int n; /* iterates over tree elements */
419 :
420 : /* Initialize the trees. */
421 12985 : for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0;
422 12985 : for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0;
423 12985 : for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0;
424 :
425 12985 : s->dyn_ltree[END_BLOCK].Freq = 1;
426 12985 : s->opt_len = s->static_len = 0L;
427 12985 : s->last_lit = s->matches = 0;
428 12985 : }
429 :
430 : #define SMALLEST 1
431 : /* Index within the heap array of least frequent node in the Huffman tree */
432 :
433 :
434 : /* ===========================================================================
435 : * Remove the smallest element from the heap and recreate the heap with
436 : * one less element. Updates heap and heap_len.
437 : */
438 : #define pqremove(s, tree, top) \
439 : {\
440 : top = s->heap[SMALLEST]; \
441 : s->heap[SMALLEST] = s->heap[s->heap_len--]; \
442 : pqdownheap(s, tree, SMALLEST); \
443 : }
444 :
445 : /* ===========================================================================
446 : * Compares to subtrees, using the tree depth as tie breaker when
447 : * the subtrees have equal frequency. This minimizes the worst case length.
448 : */
449 : #define smaller(tree, n, m, depth) \
450 : (tree[n].Freq < tree[m].Freq || \
451 : (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m]))
452 :
453 : /* ===========================================================================
454 : * Restore the heap property by moving down the tree starting at node k,
455 : * exchanging a node with the smallest of its two sons if necessary, stopping
456 : * when the heap property is re-established (each father smaller than its
457 : * two sons).
458 : */
459 5585638 : local void pqdownheap(s, tree, k)
460 : deflate_state *s;
461 : ct_data *tree; /* the tree to restore */
462 : int k; /* node to move down */
463 : {
464 5585638 : int v = s->heap[k];
465 5585638 : int j = k << 1; /* left son of k */
466 34757997 : while (j <= s->heap_len) {
467 : /* Set j to the smallest of the two sons: */
468 49543740 : if (j < s->heap_len &&
469 42838401 : smaller(tree, s->heap[j+1], s->heap[j], s->depth)) {
470 11868369 : j++;
471 : }
472 : /* Exit if v is smaller than both sons */
473 24904453 : if (smaller(tree, v, s->heap[j], s->depth)) break;
474 :
475 : /* Exchange v with the smallest son */
476 23586721 : s->heap[k] = s->heap[j]; k = j;
477 :
478 : /* And continue down the tree, setting j to the left son of k */
479 23586721 : j <<= 1;
480 : }
481 5585638 : s->heap[k] = v;
482 5585638 : }
483 :
484 : /* ===========================================================================
485 : * Compute the optimal bit lengths for a tree and update the total bit length
486 : * for the current block.
487 : * IN assertion: the fields freq and dad are set, heap[heap_max] and
488 : * above are the tree nodes sorted by increasing frequency.
489 : * OUT assertions: the field len is set to the optimal bit length, the
490 : * array bl_count contains the frequencies for each bit length.
491 : * The length opt_len is updated; static_len is also updated if stree is
492 : * not null.
493 : */
494 23304 : local void gen_bitlen(s, desc)
495 : deflate_state *s;
496 : tree_desc *desc; /* the tree descriptor */
497 : {
498 23304 : ct_data *tree = desc->dyn_tree;
499 23304 : int max_code = desc->max_code;
500 23304 : const ct_data *stree = desc->stat_desc->static_tree;
501 23304 : const intf *extra = desc->stat_desc->extra_bits;
502 23304 : int base = desc->stat_desc->extra_base;
503 23304 : int max_length = desc->stat_desc->max_length;
504 : int h; /* heap index */
505 : int n, m; /* iterate over the tree elements */
506 : int bits; /* bit length */
507 : int xbits; /* extra bits */
508 : ush f; /* frequency */
509 23304 : int overflow = 0; /* number of elements with bit length too large */
510 :
511 23304 : for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0;
512 :
513 : /* In a first pass, compute the optimal bit lengths (which may
514 : * overflow in the case of the bit length tree).
515 : */
516 23304 : tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */
517 :
518 4486460 : for (h = s->heap_max+1; h < HEAP_SIZE; h++) {
519 4463156 : n = s->heap[h];
520 4463156 : bits = tree[tree[n].Dad].Len + 1;
521 4463156 : if (bits > max_length) bits = max_length, overflow++;
522 4463156 : tree[n].Len = (ush)bits;
523 : /* We overwrite tree[n].Dad which is no longer needed */
524 :
525 4463156 : if (n > max_code) continue; /* not a leaf node */
526 :
527 2254882 : s->bl_count[bits]++;
528 2254882 : xbits = 0;
529 2254882 : if (n >= base) xbits = extra[n-base];
530 2254882 : f = tree[n].Freq;
531 2254882 : s->opt_len += (ulg)f * (bits + xbits);
532 2254882 : if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits);
533 : }
534 23304 : if (overflow == 0) return;
535 :
536 : Trace((stderr,"\nbit length overflow\n"));
537 : /* This happens for example on obj2 and pic of the Calgary corpus */
538 :
539 : /* Find the first bit length which could increase: */
540 : do {
541 1610 : bits = max_length-1;
542 1610 : while (s->bl_count[bits] == 0) bits--;
543 1610 : s->bl_count[bits]--; /* move one leaf down the tree */
544 1610 : s->bl_count[bits+1] += 2; /* move one overflow item as its brother */
545 1610 : s->bl_count[max_length]--;
546 : /* The brother of the overflow item also moves one step up,
547 : * but this does not affect bl_count[max_length]
548 : */
549 1610 : overflow -= 2;
550 1610 : } while (overflow > 0);
551 :
552 : /* Now recompute all bit lengths, scanning in increasing frequency.
553 : * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all
554 : * lengths instead of fixing only the wrong ones. This idea is taken
555 : * from 'ar' written by Haruhiko Okumura.)
556 : */
557 11672 : for (bits = max_length; bits != 0; bits--) {
558 10213 : n = s->bl_count[bits];
559 52677 : while (n != 0) {
560 32251 : m = s->heap[--h];
561 32251 : if (m > max_code) continue;
562 20973 : if ((unsigned) tree[m].Len != (unsigned) bits) {
563 : Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits));
564 2982 : s->opt_len += ((long)bits - (long)tree[m].Len)
565 1491 : *(long)tree[m].Freq;
566 1491 : tree[m].Len = (ush)bits;
567 : }
568 20973 : n--;
569 : }
570 : }
571 : }
572 :
573 : /* ===========================================================================
574 : * Generate the codes for a given tree and bit counts (which need not be
575 : * optimal).
576 : * IN assertion: the array bl_count contains the bit length statistics for
577 : * the given tree and the field len is set for all tree elements.
578 : * OUT assertion: the field code is set for all tree elements of non
579 : * zero code length.
580 : */
581 23304 : local void gen_codes (tree, max_code, bl_count)
582 : ct_data *tree; /* the tree to decorate */
583 : int max_code; /* largest code with non zero frequency */
584 : ushf *bl_count; /* number of codes at each bit length */
585 : {
586 : ush next_code[MAX_BITS+1]; /* next code value for each bit length */
587 23304 : ush code = 0; /* running code value */
588 : int bits; /* bit index */
589 : int n; /* code index */
590 :
591 : /* The distribution counts are first used to generate the code values
592 : * without bit reversal.
593 : */
594 372864 : for (bits = 1; bits <= MAX_BITS; bits++) {
595 349560 : next_code[bits] = code = (code + bl_count[bits-1]) << 1;
596 : }
597 : /* Check that the bit counts in bl_count are consistent. The last code
598 : * must be all ones.
599 : */
600 : Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1,
601 : "inconsistent bit counts");
602 : Tracev((stderr,"\ngen_codes: max_code %d ", max_code));
603 :
604 2595695 : for (n = 0; n <= max_code; n++) {
605 2572391 : int len = tree[n].Len;
606 2572391 : if (len == 0) continue;
607 : /* Now reverse the bits */
608 2254882 : tree[n].Code = bi_reverse(next_code[len]++, len);
609 :
610 : Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ",
611 : n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1));
612 : }
613 23304 : }
614 :
615 : /* ===========================================================================
616 : * Construct one Huffman tree and assigns the code bit strings and lengths.
617 : * Update the total bit length for the current block.
618 : * IN assertion: the field freq is set for all tree elements.
619 : * OUT assertions: the fields len and code are set to the optimal bit length
620 : * and corresponding code. The length opt_len is updated; static_len is
621 : * also updated if stree is not null. The field max_code is set.
622 : */
623 23304 : local void build_tree(s, desc)
624 : deflate_state *s;
625 : tree_desc *desc; /* the tree descriptor */
626 : {
627 23304 : ct_data *tree = desc->dyn_tree;
628 23304 : const ct_data *stree = desc->stat_desc->static_tree;
629 23304 : int elems = desc->stat_desc->elems;
630 : int n, m; /* iterate over heap elements */
631 23304 : int max_code = -1; /* largest code with non zero frequency */
632 : int node; /* new node being created */
633 :
634 : /* Construct the initial heap, with least frequent element in
635 : * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1].
636 : * heap[0] is not used.
637 : */
638 23304 : s->heap_len = 0, s->heap_max = HEAP_SIZE;
639 :
640 2625584 : for (n = 0; n < elems; n++) {
641 2602280 : if (tree[n].Freq != 0) {
642 2254858 : s->heap[++(s->heap_len)] = max_code = n;
643 2254858 : s->depth[n] = 0;
644 : } else {
645 347422 : tree[n].Len = 0;
646 : }
647 : }
648 :
649 : /* The pkzip format requires that at least one distance code exists,
650 : * and that at least one bit should be sent even if there is only one
651 : * possible code. So to avoid special checks later on we force at least
652 : * two codes of non zero frequency.
653 : */
654 46632 : while (s->heap_len < 2) {
655 24 : node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0);
656 24 : tree[node].Freq = 1;
657 24 : s->depth[node] = 0;
658 24 : s->opt_len--; if (stree) s->static_len -= stree[node].Len;
659 : /* node is 0 or 1 so it does not have extra bits */
660 : }
661 23304 : desc->max_code = max_code;
662 :
663 : /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree,
664 : * establish sub-heaps of increasing lengths:
665 : */
666 23304 : for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, n);
667 :
668 : /* Construct the Huffman tree by repeatedly combining the least two
669 : * frequent nodes.
670 : */
671 23304 : node = elems; /* next internal node of the tree */
672 : do {
673 2231578 : pqremove(s, tree, n); /* n = node of least frequency */
674 2231578 : m = s->heap[SMALLEST]; /* m = node of next least frequency */
675 :
676 2231578 : s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */
677 2231578 : s->heap[--(s->heap_max)] = m;
678 :
679 : /* Create a new node father of n and m */
680 2231578 : tree[node].Freq = tree[n].Freq + tree[m].Freq;
681 4463156 : s->depth[node] = (uch)((s->depth[n] >= s->depth[m] ?
682 2231578 : s->depth[n] : s->depth[m]) + 1);
683 2231578 : tree[n].Dad = tree[m].Dad = (ush)node;
684 : #ifdef DUMP_BL_TREE
685 : if (tree == s->bl_tree) {
686 : fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)",
687 : node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq);
688 : }
689 : #endif
690 : /* and insert the new node in the heap */
691 2231578 : s->heap[SMALLEST] = node++;
692 2231578 : pqdownheap(s, tree, SMALLEST);
693 :
694 2231578 : } while (s->heap_len >= 2);
695 :
696 23304 : s->heap[--(s->heap_max)] = s->heap[SMALLEST];
697 :
698 : /* At this point, the fields freq and dad are set. We can now
699 : * generate the bit lengths.
700 : */
701 23304 : gen_bitlen(s, (tree_desc *)desc);
702 :
703 : /* The field len is now set, we can generate the bit codes */
704 23304 : gen_codes ((ct_data *)tree, max_code, s->bl_count);
705 23304 : }
706 :
707 : /* ===========================================================================
708 : * Scan a literal or distance tree to determine the frequencies of the codes
709 : * in the bit length tree.
710 : */
711 15536 : local void scan_tree (s, tree, max_code)
712 : deflate_state *s;
713 : ct_data *tree; /* the tree to be scanned */
714 : int max_code; /* and its largest code of non zero frequency */
715 : {
716 : int n; /* iterates over all tree elements */
717 15536 : int prevlen = -1; /* last emitted length */
718 : int curlen; /* length of current code */
719 15536 : int nextlen = tree[0].Len; /* length of next code */
720 15536 : int count = 0; /* repeat count of the current code */
721 15536 : int max_count = 7; /* max repeat count */
722 15536 : int min_count = 4; /* min repeat count */
723 :
724 15536 : if (nextlen == 0) max_count = 138, min_count = 3;
725 15536 : tree[max_code+1].Len = (ush)0xffff; /* guard */
726 :
727 2450017 : for (n = 0; n <= max_code; n++) {
728 2434481 : curlen = nextlen; nextlen = tree[n+1].Len;
729 2434481 : if (++count < max_count && curlen == nextlen) {
730 1055823 : continue;
731 1378658 : } else if (count < min_count) {
732 1233915 : s->bl_tree[curlen].Freq += count;
733 144743 : } else if (curlen != 0) {
734 117185 : if (curlen != prevlen) s->bl_tree[curlen].Freq++;
735 117185 : s->bl_tree[REP_3_6].Freq++;
736 27558 : } else if (count <= 10) {
737 23965 : s->bl_tree[REPZ_3_10].Freq++;
738 : } else {
739 3593 : s->bl_tree[REPZ_11_138].Freq++;
740 : }
741 1378658 : count = 0; prevlen = curlen;
742 1378658 : if (nextlen == 0) {
743 105648 : max_count = 138, min_count = 3;
744 1273010 : } else if (curlen == nextlen) {
745 23507 : max_count = 6, min_count = 3;
746 : } else {
747 1249503 : max_count = 7, min_count = 4;
748 : }
749 : }
750 15536 : }
751 :
752 : /* ===========================================================================
753 : * Send a literal or distance tree in compressed form, using the codes in
754 : * bl_tree.
755 : */
756 15472 : local void send_tree (s, tree, max_code)
757 : deflate_state *s;
758 : ct_data *tree; /* the tree to be scanned */
759 : int max_code; /* and its largest code of non zero frequency */
760 : {
761 : int n; /* iterates over all tree elements */
762 15472 : int prevlen = -1; /* last emitted length */
763 : int curlen; /* length of current code */
764 15472 : int nextlen = tree[0].Len; /* length of next code */
765 15472 : int count = 0; /* repeat count of the current code */
766 15472 : int max_count = 7; /* max repeat count */
767 15472 : int min_count = 4; /* min repeat count */
768 :
769 : /* tree[max_code+1].Len = -1; */ /* guard already set */
770 15472 : if (nextlen == 0) max_count = 138, min_count = 3;
771 :
772 2441238 : for (n = 0; n <= max_code; n++) {
773 2425766 : curlen = nextlen; nextlen = tree[n+1].Len;
774 2425766 : if (++count < max_count && curlen == nextlen) {
775 1047732 : continue;
776 1378034 : } else if (count < min_count) {
777 1641609 : do { send_code(s, curlen, s->bl_tree); } while (--count != 0);
778 :
779 144587 : } else if (curlen != 0) {
780 117182 : if (curlen != prevlen) {
781 103315 : send_code(s, curlen, s->bl_tree); count--;
782 : }
783 : Assert(count >= 3 && count <= 6, " 3_6?");
784 117182 : send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2);
785 :
786 27405 : } else if (count <= 10) {
787 23891 : send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3);
788 :
789 : } else {
790 3514 : send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7);
791 : }
792 1378034 : count = 0; prevlen = curlen;
793 1378034 : if (nextlen == 0) {
794 105413 : max_count = 138, min_count = 3;
795 1272621 : } else if (curlen == nextlen) {
796 23507 : max_count = 6, min_count = 3;
797 : } else {
798 1249114 : max_count = 7, min_count = 4;
799 : }
800 : }
801 15472 : }
802 :
803 : /* ===========================================================================
804 : * Construct the Huffman tree for the bit lengths and return the index in
805 : * bl_order of the last bit length code to send.
806 : */
807 7768 : local int build_bl_tree(s)
808 : deflate_state *s;
809 : {
810 : int max_blindex; /* index of last bit length code of non zero freq */
811 :
812 : /* Determine the bit length frequencies for literal and distance trees */
813 7768 : scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code);
814 7768 : scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code);
815 :
816 : /* Build the bit length tree: */
817 7768 : build_tree(s, (tree_desc *)(&(s->bl_desc)));
818 : /* opt_len now includes the length of the tree representations, except
819 : * the lengths of the bit lengths codes and the 5+5+4 bits for the counts.
820 : */
821 :
822 : /* Determine the number of bit length codes to send. The pkzip format
823 : * requires that at least 4 bit length codes be sent. (appnote.txt says
824 : * 3 but the actual value used is 4.)
825 : */
826 37349 : for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) {
827 37349 : if (s->bl_tree[bl_order[max_blindex]].Len != 0) break;
828 : }
829 : /* Update opt_len to include the bit length tree and counts */
830 7768 : s->opt_len += 3*(max_blindex+1) + 5+5+4;
831 : Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld",
832 : s->opt_len, s->static_len));
833 :
834 7768 : return max_blindex;
835 : }
836 :
837 : /* ===========================================================================
838 : * Send the header for a block using dynamic Huffman trees: the counts, the
839 : * lengths of the bit length codes, the literal tree and the distance tree.
840 : * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.
841 : */
842 7736 : local void send_all_trees(s, lcodes, dcodes, blcodes)
843 : deflate_state *s;
844 : int lcodes, dcodes, blcodes; /* number of codes for each tree */
845 : {
846 : int rank; /* index in bl_order */
847 :
848 : Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes");
849 : Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES,
850 : "too many codes");
851 : Tracev((stderr, "\nbl counts: "));
852 7736 : send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */
853 7736 : send_bits(s, dcodes-1, 5);
854 7736 : send_bits(s, blcodes-4, 4); /* not -3 as stated in appnote.txt */
855 125175 : for (rank = 0; rank < blcodes; rank++) {
856 : Tracev((stderr, "\nbl code %2d ", bl_order[rank]));
857 117439 : send_bits(s, s->bl_tree[bl_order[rank]].Len, 3);
858 : }
859 : Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent));
860 :
861 7736 : send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */
862 : Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent));
863 :
864 7736 : send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */
865 : Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent));
866 7736 : }
867 :
868 : /* ===========================================================================
869 : * Send a stored block
870 : */
871 0 : void ZLIB_INTERNAL _tr_stored_block(s, buf, stored_len, last)
872 : deflate_state *s;
873 : charf *buf; /* input block */
874 : ulg stored_len; /* length of input block */
875 : int last; /* one if this is the last block for a file */
876 : {
877 0 : send_bits(s, (STORED_BLOCK<<1)+last, 3); /* send block type */
878 : #ifdef DEBUG
879 : s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L;
880 : s->compressed_len += (stored_len + 4) << 3;
881 : #endif
882 0 : copy_block(s, buf, (unsigned)stored_len, 1); /* with header */
883 0 : }
884 :
885 : /* ===========================================================================
886 : * Send one empty static block to give enough lookahead for inflate.
887 : * This takes 10 bits, of which 7 may remain in the bit buffer.
888 : * The current inflate code requires 9 bits of lookahead. If the
889 : * last two codes for the previous block (real code plus EOB) were coded
890 : * on 5 bits or less, inflate may have only 5+3 bits of lookahead to decode
891 : * the last real code. In this case we send two empty static blocks instead
892 : * of one. (There are no problems if the previous block is stored or fixed.)
893 : * To simplify the code, we assume the worst case of last real code encoded
894 : * on one bit only.
895 : */
896 0 : void ZLIB_INTERNAL _tr_align(s)
897 : deflate_state *s;
898 : {
899 0 : send_bits(s, STATIC_TREES<<1, 3);
900 0 : send_code(s, END_BLOCK, static_ltree);
901 : #ifdef DEBUG
902 : s->compressed_len += 10L; /* 3 for block type, 7 for EOB */
903 : #endif
904 0 : bi_flush(s);
905 : /* Of the 10 bits for the empty block, we have already sent
906 : * (10 - bi_valid) bits. The lookahead for the last real code (before
907 : * the EOB of the previous block) was thus at least one plus the length
908 : * of the EOB plus what we have just sent of the empty static block.
909 : */
910 0 : if (1 + s->last_eob_len + 10 - s->bi_valid < 9) {
911 0 : send_bits(s, STATIC_TREES<<1, 3);
912 0 : send_code(s, END_BLOCK, static_ltree);
913 : #ifdef DEBUG
914 : s->compressed_len += 10L;
915 : #endif
916 0 : bi_flush(s);
917 : }
918 0 : s->last_eob_len = 7;
919 0 : }
920 :
921 : /* ===========================================================================
922 : * Determine the best encoding for the current block: dynamic trees, static
923 : * trees or store, and output the encoded block to the zip file.
924 : */
925 7768 : void ZLIB_INTERNAL _tr_flush_block(s, buf, stored_len, last)
926 : deflate_state *s;
927 : charf *buf; /* input block, or NULL if too old */
928 : ulg stored_len; /* length of input block */
929 : int last; /* one if this is the last block for a file */
930 : {
931 : ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */
932 7768 : int max_blindex = 0; /* index of last bit length code of non zero freq */
933 :
934 : /* Build the Huffman trees unless a stored block is forced */
935 7768 : if (s->level > 0) {
936 :
937 : /* Check if the file is binary or text */
938 7768 : if (s->strm->data_type == Z_UNKNOWN)
939 5178 : s->strm->data_type = detect_data_type(s);
940 :
941 : /* Construct the literal and distance trees */
942 7768 : build_tree(s, (tree_desc *)(&(s->l_desc)));
943 : Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len,
944 : s->static_len));
945 :
946 7768 : build_tree(s, (tree_desc *)(&(s->d_desc)));
947 : Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len,
948 : s->static_len));
949 : /* At this point, opt_len and static_len are the total bit lengths of
950 : * the compressed block data, excluding the tree representations.
951 : */
952 :
953 : /* Build the bit length tree for the above two trees, and get the index
954 : * in bl_order of the last bit length code to send.
955 : */
956 7768 : max_blindex = build_bl_tree(s);
957 :
958 : /* Determine the best encoding. Compute the block lengths in bytes. */
959 7768 : opt_lenb = (s->opt_len+3+7)>>3;
960 7768 : static_lenb = (s->static_len+3+7)>>3;
961 :
962 : Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ",
963 : opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len,
964 : s->last_lit));
965 :
966 7768 : if (static_lenb <= opt_lenb) opt_lenb = static_lenb;
967 :
968 : } else {
969 : Assert(buf != (char*)0, "lost buf");
970 0 : opt_lenb = static_lenb = stored_len + 5; /* force a stored block */
971 : }
972 :
973 : #ifdef FORCE_STORED
974 : if (buf != (char*)0) { /* force stored block */
975 : #else
976 7768 : if (stored_len+4 <= opt_lenb && buf != (char*)0) {
977 : /* 4: two words for the lengths */
978 : #endif
979 : /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.
980 : * Otherwise we can't have processed more than WSIZE input bytes since
981 : * the last block flush, because compression would have been
982 : * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to
983 : * transform a block into a stored block.
984 : */
985 0 : _tr_stored_block(s, buf, stored_len, last);
986 :
987 : #ifdef FORCE_STATIC
988 : } else if (static_lenb >= 0) { /* force static trees */
989 : #else
990 7768 : } else if (s->strategy == Z_FIXED || static_lenb == opt_lenb) {
991 : #endif
992 32 : send_bits(s, (STATIC_TREES<<1)+last, 3);
993 32 : compress_block(s, (ct_data *)static_ltree, (ct_data *)static_dtree);
994 : #ifdef DEBUG
995 : s->compressed_len += 3 + s->static_len;
996 : #endif
997 : } else {
998 7736 : send_bits(s, (DYN_TREES<<1)+last, 3);
999 7736 : send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1,
1000 : max_blindex+1);
1001 7736 : compress_block(s, (ct_data *)s->dyn_ltree, (ct_data *)s->dyn_dtree);
1002 : #ifdef DEBUG
1003 : s->compressed_len += 3 + s->opt_len;
1004 : #endif
1005 : }
1006 : Assert (s->compressed_len == s->bits_sent, "bad compressed size");
1007 : /* The above check is made mod 2^32, for files larger than 512 MB
1008 : * and uLong implemented on 32 bits.
1009 : */
1010 7768 : init_block(s);
1011 :
1012 7768 : if (last) {
1013 5191 : bi_windup(s);
1014 : #ifdef DEBUG
1015 : s->compressed_len += 7; /* align on byte boundary */
1016 : #endif
1017 : }
1018 : Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3,
1019 : s->compressed_len-7*last));
1020 7768 : }
1021 :
1022 : /* ===========================================================================
1023 : * Save the match info and tally the frequency counts. Return true if
1024 : * the current block must be flushed.
1025 : */
1026 0 : int ZLIB_INTERNAL _tr_tally (s, dist, lc)
1027 : deflate_state *s;
1028 : unsigned dist; /* distance of matched string */
1029 : unsigned lc; /* match length-MIN_MATCH or unmatched char (if dist==0) */
1030 : {
1031 0 : s->d_buf[s->last_lit] = (ush)dist;
1032 0 : s->l_buf[s->last_lit++] = (uch)lc;
1033 0 : if (dist == 0) {
1034 : /* lc is the unmatched char */
1035 0 : s->dyn_ltree[lc].Freq++;
1036 : } else {
1037 0 : s->matches++;
1038 : /* Here, lc is the match length - MIN_MATCH */
1039 0 : dist--; /* dist = match distance - 1 */
1040 : Assert((ush)dist < (ush)MAX_DIST(s) &&
1041 : (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) &&
1042 : (ush)d_code(dist) < (ush)D_CODES, "_tr_tally: bad match");
1043 :
1044 0 : s->dyn_ltree[_length_code[lc]+LITERALS+1].Freq++;
1045 0 : s->dyn_dtree[d_code(dist)].Freq++;
1046 : }
1047 :
1048 : #ifdef TRUNCATE_BLOCK
1049 : /* Try to guess if it is profitable to stop the current block here */
1050 : if ((s->last_lit & 0x1fff) == 0 && s->level > 2) {
1051 : /* Compute an upper bound for the compressed length */
1052 : ulg out_length = (ulg)s->last_lit*8L;
1053 : ulg in_length = (ulg)((long)s->strstart - s->block_start);
1054 : int dcode;
1055 : for (dcode = 0; dcode < D_CODES; dcode++) {
1056 : out_length += (ulg)s->dyn_dtree[dcode].Freq *
1057 : (5L+extra_dbits[dcode]);
1058 : }
1059 : out_length >>= 3;
1060 : Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ",
1061 : s->last_lit, in_length, out_length,
1062 : 100L - out_length*100L/in_length));
1063 : if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1;
1064 : }
1065 : #endif
1066 0 : return (s->last_lit == s->lit_bufsize-1);
1067 : /* We avoid equality with lit_bufsize because of wraparound at 64K
1068 : * on 16 bit machines and because stored blocks are restricted to
1069 : * 64K-1 bytes.
1070 : */
1071 : }
1072 :
1073 : /* ===========================================================================
1074 : * Send the block data compressed using the given Huffman trees
1075 : */
1076 7768 : local void compress_block(s, ltree, dtree)
1077 : deflate_state *s;
1078 : ct_data *ltree; /* literal tree */
1079 : ct_data *dtree; /* distance tree */
1080 : {
1081 : unsigned dist; /* distance of matched string */
1082 : int lc; /* match length or unmatched char (if dist == 0) */
1083 7768 : unsigned lx = 0; /* running index in l_buf */
1084 : unsigned code; /* the code to send */
1085 : int extra; /* number of extra bits to send */
1086 :
1087 7768 : if (s->last_lit != 0) do {
1088 69755658 : dist = s->d_buf[lx];
1089 69755658 : lc = s->l_buf[lx++];
1090 69755658 : if (dist == 0) {
1091 22855595 : send_code(s, lc, ltree); /* send a literal byte */
1092 : Tracecv(isgraph(lc), (stderr," '%c' ", lc));
1093 : } else {
1094 : /* Here, lc is the match length - MIN_MATCH */
1095 46900063 : code = _length_code[lc];
1096 46900063 : send_code(s, code+LITERALS+1, ltree); /* send the length code */
1097 46900063 : extra = extra_lbits[code];
1098 46900063 : if (extra != 0) {
1099 14887972 : lc -= base_length[code];
1100 14887972 : send_bits(s, lc, extra); /* send the extra length bits */
1101 : }
1102 46900063 : dist--; /* dist is now the match distance - 1 */
1103 46900063 : code = d_code(dist);
1104 : Assert (code < D_CODES, "bad d_code");
1105 :
1106 46900063 : send_code(s, code, dtree); /* send the distance code */
1107 46900063 : extra = extra_dbits[code];
1108 46900063 : if (extra != 0) {
1109 45935192 : dist -= base_dist[code];
1110 45935192 : send_bits(s, dist, extra); /* send the extra distance bits */
1111 : }
1112 : } /* literal or match pair ? */
1113 :
1114 : /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */
1115 : Assert((uInt)(s->pending) < s->lit_bufsize + 2*lx,
1116 : "pendingBuf overflow");
1117 :
1118 69755658 : } while (lx < s->last_lit);
1119 :
1120 7768 : send_code(s, END_BLOCK, ltree);
1121 7768 : s->last_eob_len = ltree[END_BLOCK].Len;
1122 7768 : }
1123 :
1124 : /* ===========================================================================
1125 : * Check if the data type is TEXT or BINARY, using the following algorithm:
1126 : * - TEXT if the two conditions below are satisfied:
1127 : * a) There are no non-portable control characters belonging to the
1128 : * "black list" (0..6, 14..25, 28..31).
1129 : * b) There is at least one printable character belonging to the
1130 : * "white list" (9 {TAB}, 10 {LF}, 13 {CR}, 32..255).
1131 : * - BINARY otherwise.
1132 : * - The following partially-portable control characters form a
1133 : * "gray list" that is ignored in this detection algorithm:
1134 : * (7 {BEL}, 8 {BS}, 11 {VT}, 12 {FF}, 26 {SUB}, 27 {ESC}).
1135 : * IN assertion: the fields Freq of dyn_ltree are set.
1136 : */
1137 5178 : local int detect_data_type(s)
1138 : deflate_state *s;
1139 : {
1140 : /* black_mask is the bit mask of black-listed bytes
1141 : * set bits 0..6, 14..25, and 28..31
1142 : * 0xf3ffc07f = binary 11110011111111111100000001111111
1143 : */
1144 5178 : unsigned long black_mask = 0xf3ffc07fUL;
1145 : int n;
1146 :
1147 : /* Check for non-textual ("black-listed") bytes. */
1148 5466 : for (n = 0; n <= 31; n++, black_mask >>= 1)
1149 5457 : if ((black_mask & 1) && (s->dyn_ltree[n].Freq != 0))
1150 5169 : return Z_BINARY;
1151 :
1152 : /* Check for textual ("white-listed") bytes. */
1153 9 : if (s->dyn_ltree[9].Freq != 0 || s->dyn_ltree[10].Freq != 0
1154 7 : || s->dyn_ltree[13].Freq != 0)
1155 2 : return Z_TEXT;
1156 463 : for (n = 32; n < LITERALS; n++)
1157 461 : if (s->dyn_ltree[n].Freq != 0)
1158 5 : return Z_TEXT;
1159 :
1160 : /* There are no "black-listed" or "white-listed" bytes:
1161 : * this stream either is empty or has tolerated ("gray-listed") bytes only.
1162 : */
1163 2 : return Z_BINARY;
1164 : }
1165 :
1166 : /* ===========================================================================
1167 : * Reverse the first len bits of a code, using straightforward code (a faster
1168 : * method would use a table)
1169 : * IN assertion: 1 <= len <= 15
1170 : */
1171 2254882 : local unsigned bi_reverse(code, len)
1172 : unsigned code; /* the value to invert */
1173 : int len; /* its bit length */
1174 : {
1175 2254882 : register unsigned res = 0;
1176 : do {
1177 20372186 : res |= code & 1;
1178 20372186 : code >>= 1, res <<= 1;
1179 20372186 : } while (--len > 0);
1180 2254882 : return res >> 1;
1181 : }
1182 :
1183 : /* ===========================================================================
1184 : * Flush the bit buffer, keeping at most 7 bits in it.
1185 : */
1186 0 : local void bi_flush(s)
1187 : deflate_state *s;
1188 : {
1189 0 : if (s->bi_valid == 16) {
1190 0 : put_short(s, s->bi_buf);
1191 0 : s->bi_buf = 0;
1192 0 : s->bi_valid = 0;
1193 0 : } else if (s->bi_valid >= 8) {
1194 0 : put_byte(s, (Byte)s->bi_buf);
1195 0 : s->bi_buf >>= 8;
1196 0 : s->bi_valid -= 8;
1197 : }
1198 0 : }
1199 :
1200 : /* ===========================================================================
1201 : * Flush the bit buffer and align the output on a byte boundary
1202 : */
1203 5191 : local void bi_windup(s)
1204 : deflate_state *s;
1205 : {
1206 5191 : if (s->bi_valid > 8) {
1207 3200 : put_short(s, s->bi_buf);
1208 1991 : } else if (s->bi_valid > 0) {
1209 1991 : put_byte(s, (Byte)s->bi_buf);
1210 : }
1211 5191 : s->bi_buf = 0;
1212 5191 : s->bi_valid = 0;
1213 : #ifdef DEBUG
1214 : s->bits_sent = (s->bits_sent+7) & ~7;
1215 : #endif
1216 5191 : }
1217 :
1218 : /* ===========================================================================
1219 : * Copy a stored block, storing first the length and its
1220 : * one's complement if requested.
1221 : */
1222 0 : local void copy_block(s, buf, len, header)
1223 : deflate_state *s;
1224 : charf *buf; /* the input data */
1225 : unsigned len; /* its length */
1226 : int header; /* true if block header must be written */
1227 : {
1228 0 : bi_windup(s); /* align on byte boundary */
1229 0 : s->last_eob_len = 8; /* enough lookahead for inflate */
1230 :
1231 0 : if (header) {
1232 0 : put_short(s, (ush)len);
1233 0 : put_short(s, (ush)~len);
1234 : #ifdef DEBUG
1235 : s->bits_sent += 2*16;
1236 : #endif
1237 : }
1238 : #ifdef DEBUG
1239 : s->bits_sent += (ulg)len<<3;
1240 : #endif
1241 0 : while (len--) {
1242 0 : put_byte(s, *buf++);
1243 : }
1244 0 : }
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