Line data Source code
1 : /* $OpenBSD: trees.c,v 1.3 2016/03/14 23:08:06 krw Exp $ */
2 : /* trees.c -- output deflated data using Huffman coding
3 : * Copyright (C) 1995-2005 Jean-loup Gailly
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 :
34 : /* #define GEN_TREES_H */
35 :
36 : #include "deflate.h"
37 :
38 : #ifdef DEBUG_LIBZ
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_LIBZ
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_LIBZ */
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_LIBZ
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_LIBZ */
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_LIBZ */
231 :
232 :
233 : /* the arguments must not have side effects */
234 :
235 : /* ===========================================================================
236 : * Initialize the various 'constant' tables.
237 : */
238 0 : 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 0 : }
317 :
318 : /* ===========================================================================
319 : * Genererate the file trees.h describing the static trees.
320 : */
321 : #ifdef GEN_TREES_H
322 : # ifndef DEBUG_LIBZ
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 0 : void _tr_init(s)
383 : deflate_state *s;
384 : {
385 0 : tr_static_init();
386 :
387 0 : s->l_desc.dyn_tree = s->dyn_ltree;
388 0 : s->l_desc.stat_desc = &static_l_desc;
389 :
390 0 : s->d_desc.dyn_tree = s->dyn_dtree;
391 0 : s->d_desc.stat_desc = &static_d_desc;
392 :
393 0 : s->bl_desc.dyn_tree = s->bl_tree;
394 0 : s->bl_desc.stat_desc = &static_bl_desc;
395 :
396 0 : s->bi_buf = 0;
397 0 : s->bi_valid = 0;
398 0 : s->last_eob_len = 8; /* enough lookahead for inflate */
399 : #ifdef DEBUG_LIBZ
400 : s->compressed_len = 0L;
401 : s->bits_sent = 0L;
402 : #endif
403 :
404 : /* Initialize the first block of the first file: */
405 0 : init_block(s);
406 0 : }
407 :
408 : /* ===========================================================================
409 : * Initialize a new block.
410 : */
411 0 : local void init_block(s)
412 : deflate_state *s;
413 : {
414 : int n; /* iterates over tree elements */
415 :
416 : /* Initialize the trees. */
417 0 : for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0;
418 0 : for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0;
419 0 : for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0;
420 :
421 0 : s->dyn_ltree[END_BLOCK].Freq = 1;
422 0 : s->opt_len = s->static_len = 0L;
423 0 : s->last_lit = s->matches = 0;
424 0 : }
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 0 : 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 0 : int v = s->heap[k];
461 0 : int j = k << 1; /* left son of k */
462 0 : while (j <= s->heap_len) {
463 : /* Set j to the smallest of the two sons: */
464 0 : if (j < s->heap_len &&
465 0 : smaller(tree, s->heap[j+1], s->heap[j], s->depth)) {
466 : j++;
467 0 : }
468 : /* Exit if v is smaller than both sons */
469 0 : if (smaller(tree, v, s->heap[j], s->depth)) break;
470 :
471 : /* Exchange v with the smallest son */
472 0 : s->heap[k] = s->heap[j]; k = j;
473 :
474 : /* And continue down the tree, setting j to the left son of k */
475 0 : j <<= 1;
476 : }
477 0 : s->heap[k] = v;
478 0 : }
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 0 : local void gen_bitlen(s, desc)
491 : deflate_state *s;
492 : tree_desc *desc; /* the tree descriptor */
493 : {
494 0 : ct_data *tree = desc->dyn_tree;
495 0 : int max_code = desc->max_code;
496 0 : const ct_data *stree = desc->stat_desc->static_tree;
497 0 : const intf *extra = desc->stat_desc->extra_bits;
498 0 : int base = desc->stat_desc->extra_base;
499 0 : 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 0 : 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 0 : tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */
513 :
514 0 : for (h = s->heap_max+1; h < HEAP_SIZE; h++) {
515 0 : n = s->heap[h];
516 0 : bits = tree[tree[n].Dad].Len + 1;
517 0 : if (bits > max_length) bits = max_length, overflow++;
518 0 : tree[n].Len = (ush)bits;
519 : /* We overwrite tree[n].Dad which is no longer needed */
520 :
521 0 : if (n > max_code) continue; /* not a leaf node */
522 :
523 0 : s->bl_count[bits]++;
524 : xbits = 0;
525 0 : if (n >= base) xbits = extra[n-base];
526 0 : f = tree[n].Freq;
527 0 : s->opt_len += (ulg)f * (bits + xbits);
528 0 : if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits);
529 : }
530 0 : 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 0 : do {
537 0 : bits = max_length-1;
538 0 : while (s->bl_count[bits] == 0) bits--;
539 0 : s->bl_count[bits]--; /* move one leaf down the tree */
540 0 : s->bl_count[bits+1] += 2; /* move one overflow item as its brother */
541 0 : 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 0 : overflow -= 2;
546 0 : } 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 0 : for (bits = max_length; bits != 0; bits--) {
554 0 : n = s->bl_count[bits];
555 0 : while (n != 0) {
556 0 : m = s->heap[--h];
557 0 : if (m > max_code) continue;
558 0 : if ((unsigned) tree[m].Len != (unsigned) bits) {
559 : Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits));
560 0 : s->opt_len += ((long)bits - (long)tree[m].Len)
561 0 : *(long)tree[m].Freq;
562 0 : tree[m].Len = (ush)bits;
563 0 : }
564 0 : n--;
565 : }
566 : }
567 0 : }
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 0 : 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 0 : 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 0 : for (bits = 1; bits <= MAX_BITS; bits++) {
591 0 : 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 0 : for (n = 0; n <= max_code; n++) {
601 0 : int len = tree[n].Len;
602 0 : if (len == 0) continue;
603 : /* Now reverse the bits */
604 0 : 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 0 : }
609 0 : }
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 0 : local void build_tree(s, desc)
620 : deflate_state *s;
621 : tree_desc *desc; /* the tree descriptor */
622 : {
623 0 : ct_data *tree = desc->dyn_tree;
624 0 : const ct_data *stree = desc->stat_desc->static_tree;
625 0 : 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 0 : s->heap_len = 0, s->heap_max = HEAP_SIZE;
635 :
636 0 : for (n = 0; n < elems; n++) {
637 0 : if (tree[n].Freq != 0) {
638 0 : s->heap[++(s->heap_len)] = max_code = n;
639 0 : s->depth[n] = 0;
640 0 : } else {
641 0 : 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 0 : while (s->heap_len < 2) {
651 0 : node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0);
652 0 : tree[node].Freq = 1;
653 0 : s->depth[node] = 0;
654 0 : 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 0 : 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 0 : 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 0 : do {
669 0 : pqremove(s, tree, n); /* n = node of least frequency */
670 0 : m = s->heap[SMALLEST]; /* m = node of next least frequency */
671 :
672 0 : s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */
673 0 : s->heap[--(s->heap_max)] = m;
674 :
675 : /* Create a new node father of n and m */
676 0 : tree[node].Freq = tree[n].Freq + tree[m].Freq;
677 0 : s->depth[node] = (uch)((s->depth[n] >= s->depth[m] ?
678 0 : s->depth[n] : s->depth[m]) + 1);
679 0 : 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 0 : s->heap[SMALLEST] = node++;
688 0 : pqdownheap(s, tree, SMALLEST);
689 :
690 0 : } while (s->heap_len >= 2);
691 :
692 0 : 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 0 : gen_bitlen(s, (tree_desc *)desc);
698 :
699 : /* The field len is now set, we can generate the bit codes */
700 0 : gen_codes ((ct_data *)tree, max_code, s->bl_count);
701 0 : }
702 :
703 : /* ===========================================================================
704 : * Scan a literal or distance tree to determine the frequencies of the codes
705 : * in the bit length tree.
706 : */
707 0 : 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 0 : 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 0 : if (nextlen == 0) max_count = 138, min_count = 3;
721 0 : tree[max_code+1].Len = (ush)0xffff; /* guard */
722 :
723 0 : for (n = 0; n <= max_code; n++) {
724 0 : curlen = nextlen; nextlen = tree[n+1].Len;
725 0 : if (++count < max_count && curlen == nextlen) {
726 : continue;
727 0 : } else if (count < min_count) {
728 0 : s->bl_tree[curlen].Freq += count;
729 0 : } else if (curlen != 0) {
730 0 : if (curlen != prevlen) s->bl_tree[curlen].Freq++;
731 0 : s->bl_tree[REP_3_6].Freq++;
732 0 : } else if (count <= 10) {
733 0 : s->bl_tree[REPZ_3_10].Freq++;
734 0 : } else {
735 0 : s->bl_tree[REPZ_11_138].Freq++;
736 : }
737 : count = 0; prevlen = curlen;
738 0 : if (nextlen == 0) {
739 : max_count = 138, min_count = 3;
740 0 : } else if (curlen == nextlen) {
741 : max_count = 6, min_count = 3;
742 0 : } else {
743 : max_count = 7, min_count = 4;
744 : }
745 : }
746 0 : }
747 :
748 : /* ===========================================================================
749 : * Send a literal or distance tree in compressed form, using the codes in
750 : * bl_tree.
751 : */
752 0 : 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 0 : 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 0 : if (nextlen == 0) max_count = 138, min_count = 3;
767 :
768 0 : for (n = 0; n <= max_code; n++) {
769 0 : curlen = nextlen; nextlen = tree[n+1].Len;
770 0 : if (++count < max_count && curlen == nextlen) {
771 : continue;
772 0 : } else if (count < min_count) {
773 0 : do { send_code(s, curlen, s->bl_tree); } while (--count != 0);
774 :
775 0 : } else if (curlen != 0) {
776 0 : if (curlen != prevlen) {
777 0 : send_code(s, curlen, s->bl_tree); count--;
778 0 : }
779 : Assert(count >= 3 && count <= 6, " 3_6?");
780 0 : send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2);
781 :
782 0 : } else if (count <= 10) {
783 0 : send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3);
784 :
785 0 : } else {
786 0 : send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7);
787 : }
788 : count = 0; prevlen = curlen;
789 0 : if (nextlen == 0) {
790 : max_count = 138, min_count = 3;
791 0 : } else if (curlen == nextlen) {
792 : max_count = 6, min_count = 3;
793 0 : } else {
794 : max_count = 7, min_count = 4;
795 : }
796 : }
797 0 : }
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 0 : 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 0 : scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code);
810 0 : scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code);
811 :
812 : /* Build the bit length tree: */
813 0 : 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 0 : for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) {
823 0 : 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 0 : 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 0 : 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 0 : 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 0 : send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */
849 0 : send_bits(s, dcodes-1, 5);
850 0 : send_bits(s, blcodes-4, 4); /* not -3 as stated in appnote.txt */
851 0 : for (rank = 0; rank < blcodes; rank++) {
852 : Tracev((stderr, "\nbl code %2d ", bl_order[rank]));
853 0 : send_bits(s, s->bl_tree[bl_order[rank]].Len, 3);
854 : }
855 : Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent));
856 :
857 0 : send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */
858 : Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent));
859 :
860 0 : send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */
861 : Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent));
862 0 : }
863 :
864 : /* ===========================================================================
865 : * Send a stored block
866 : */
867 0 : 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 0 : send_bits(s, (STORED_BLOCK<<1)+eof, 3); /* send block type */
874 : #ifdef DEBUG_LIBZ
875 : s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L;
876 : s->compressed_len += (stored_len + 4) << 3;
877 : #endif
878 0 : copy_block(s, buf, (unsigned)stored_len, 1); /* with header */
879 0 : }
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 0 : void _tr_align(s)
893 : deflate_state *s;
894 : {
895 0 : send_bits(s, STATIC_TREES<<1, 3);
896 0 : send_code(s, END_BLOCK, static_ltree);
897 : #ifdef DEBUG_LIBZ
898 : s->compressed_len += 10L; /* 3 for block type, 7 for EOB */
899 : #endif
900 0 : 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 0 : if (1 + s->last_eob_len + 10 - s->bi_valid < 9) {
907 0 : send_bits(s, STATIC_TREES<<1, 3);
908 0 : send_code(s, END_BLOCK, static_ltree);
909 : #ifdef DEBUG_LIBZ
910 : s->compressed_len += 10L;
911 : #endif
912 0 : bi_flush(s);
913 0 : }
914 0 : s->last_eob_len = 7;
915 0 : }
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 0 : 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 0 : if (s->level > 0) {
932 :
933 : /* Check if the file is binary or text */
934 0 : if (stored_len > 0 && s->strm->data_type == Z_UNKNOWN)
935 0 : set_data_type(s);
936 :
937 : /* Construct the literal and distance trees */
938 0 : 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 0 : 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 0 : max_blindex = build_bl_tree(s);
953 :
954 : /* Determine the best encoding. Compute the block lengths in bytes. */
955 0 : opt_lenb = (s->opt_len+3+7)>>3;
956 0 : 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 0 : if (static_lenb <= opt_lenb) opt_lenb = static_lenb;
963 :
964 : } else {
965 : Assert(buf != NULL, "lost buf");
966 0 : opt_lenb = static_lenb = stored_len + 5; /* force a stored block */
967 : }
968 :
969 : #ifdef FORCE_STORED
970 : if (buf != NULL) { /* force stored block */
971 : #else
972 0 : if (stored_len+4 <= opt_lenb && buf != NULL) {
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 0 : _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 0 : } else if (s->strategy == Z_FIXED || static_lenb == opt_lenb) {
987 : #endif
988 0 : send_bits(s, (STATIC_TREES<<1)+eof, 3);
989 0 : compress_block(s, (ct_data *)static_ltree, (ct_data *)static_dtree);
990 : #ifdef DEBUG_LIBZ
991 : s->compressed_len += 3 + s->static_len;
992 : #endif
993 0 : } else {
994 0 : send_bits(s, (DYN_TREES<<1)+eof, 3);
995 0 : send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1,
996 0 : max_blindex+1);
997 0 : compress_block(s, (ct_data *)s->dyn_ltree, (ct_data *)s->dyn_dtree);
998 : #ifdef DEBUG_LIBZ
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 0 : init_block(s);
1007 :
1008 0 : if (eof) {
1009 0 : bi_windup(s);
1010 : #ifdef DEBUG_LIBZ
1011 : s->compressed_len += 7; /* align on byte boundary */
1012 : #endif
1013 0 : }
1014 : Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3,
1015 : s->compressed_len-7*eof));
1016 0 : }
1017 :
1018 : /* ===========================================================================
1019 : * Save the match info and tally the frequency counts. Return true if
1020 : * the current block must be flushed.
1021 : */
1022 0 : 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 0 : s->d_buf[s->last_lit] = (ush)dist;
1028 0 : s->l_buf[s->last_lit++] = (uch)lc;
1029 0 : if (dist == 0) {
1030 : /* lc is the unmatched char */
1031 0 : s->dyn_ltree[lc].Freq++;
1032 0 : } else {
1033 0 : s->matches++;
1034 : /* Here, lc is the match length - MIN_MATCH */
1035 0 : 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 0 : s->dyn_ltree[_length_code[lc]+LITERALS+1].Freq++;
1041 0 : 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 0 : 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 0 : 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 0 : if (s->last_lit != 0) do {
1084 0 : dist = s->d_buf[lx];
1085 0 : lc = s->l_buf[lx++];
1086 0 : if (dist == 0) {
1087 0 : send_code(s, lc, ltree); /* send a literal byte */
1088 : Tracecv(isgraph(lc), (stderr," '%c' ", lc));
1089 0 : } else {
1090 : /* Here, lc is the match length - MIN_MATCH */
1091 0 : code = _length_code[lc];
1092 0 : send_code(s, code+LITERALS+1, ltree); /* send the length code */
1093 0 : extra = extra_lbits[code];
1094 0 : if (extra != 0) {
1095 0 : lc -= base_length[code];
1096 0 : send_bits(s, lc, extra); /* send the extra length bits */
1097 0 : }
1098 0 : dist--; /* dist is now the match distance - 1 */
1099 0 : code = d_code(dist);
1100 : Assert (code < D_CODES, "bad d_code");
1101 :
1102 0 : send_code(s, code, dtree); /* send the distance code */
1103 0 : extra = extra_dbits[code];
1104 0 : if (extra != 0) {
1105 0 : dist -= base_dist[code];
1106 0 : send_bits(s, dist, extra); /* send the extra distance bits */
1107 0 : }
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 0 : } while (lx < s->last_lit);
1115 :
1116 0 : send_code(s, END_BLOCK, ltree);
1117 0 : s->last_eob_len = ltree[END_BLOCK].Len;
1118 0 : }
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 0 : local void set_data_type(s)
1127 : deflate_state *s;
1128 : {
1129 : int n;
1130 :
1131 0 : for (n = 0; n < 9; n++)
1132 0 : if (s->dyn_ltree[n].Freq != 0)
1133 : break;
1134 0 : if (n == 9)
1135 0 : for (n = 14; n < 32; n++)
1136 0 : if (s->dyn_ltree[n].Freq != 0)
1137 : break;
1138 0 : s->strm->data_type = (n == 32) ? Z_TEXT : Z_BINARY;
1139 0 : }
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 0 : 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 0 : do {
1152 0 : res |= code & 1;
1153 0 : code >>= 1, res <<= 1;
1154 0 : } while (--len > 0);
1155 0 : return res >> 1;
1156 : }
1157 :
1158 : /* ===========================================================================
1159 : * Flush the bit buffer, keeping at most 7 bits in it.
1160 : */
1161 0 : local void bi_flush(s)
1162 : deflate_state *s;
1163 : {
1164 0 : if (s->bi_valid == 16) {
1165 0 : put_short(s, s->bi_buf);
1166 0 : s->bi_buf = 0;
1167 0 : s->bi_valid = 0;
1168 0 : } else if (s->bi_valid >= 8) {
1169 0 : put_byte(s, (Byte)s->bi_buf);
1170 0 : s->bi_buf >>= 8;
1171 0 : s->bi_valid -= 8;
1172 0 : }
1173 0 : }
1174 :
1175 : /* ===========================================================================
1176 : * Flush the bit buffer and align the output on a byte boundary
1177 : */
1178 0 : local void bi_windup(s)
1179 : deflate_state *s;
1180 : {
1181 0 : if (s->bi_valid > 8) {
1182 0 : put_short(s, s->bi_buf);
1183 0 : } else if (s->bi_valid > 0) {
1184 0 : put_byte(s, (Byte)s->bi_buf);
1185 0 : }
1186 0 : s->bi_buf = 0;
1187 0 : s->bi_valid = 0;
1188 : #ifdef DEBUG_LIBZ
1189 : s->bits_sent = (s->bits_sent+7) & ~7;
1190 : #endif
1191 0 : }
1192 :
1193 : /* ===========================================================================
1194 : * Copy a stored block, storing first the length and its
1195 : * one's complement if requested.
1196 : */
1197 0 : 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 0 : bi_windup(s); /* align on byte boundary */
1204 0 : s->last_eob_len = 8; /* enough lookahead for inflate */
1205 :
1206 0 : if (header) {
1207 0 : put_short(s, (ush)len);
1208 0 : put_short(s, (ush)~len);
1209 : #ifdef DEBUG_LIBZ
1210 : s->bits_sent += 2*16;
1211 : #endif
1212 0 : }
1213 : #ifdef DEBUG_LIBZ
1214 : s->bits_sent += (ulg)len<<3;
1215 : #endif
1216 0 : while (len--) {
1217 0 : put_byte(s, *buf++);
1218 : }
1219 0 : }
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