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1 : : /* +++ trees.c */
2 : : /* trees.c -- output deflated data using Huffman coding
3 : : * Copyright (C) 1995-1996 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 : : /* From: trees.c,v 1.11 1996/07/24 13:41:06 me Exp $ */
34 : :
35 : : /* #include "deflate.h" */
36 : :
37 : : #include <linux/zutil.h>
38 : : #include "defutil.h"
39 : :
40 : : #ifdef DEBUG_ZLIB
41 : : # include <ctype.h>
42 : : #endif
43 : :
44 : : /* ===========================================================================
45 : : * Constants
46 : : */
47 : :
48 : : #define MAX_BL_BITS 7
49 : : /* Bit length codes must not exceed MAX_BL_BITS bits */
50 : :
51 : : #define END_BLOCK 256
52 : : /* end of block literal code */
53 : :
54 : : #define REP_3_6 16
55 : : /* repeat previous bit length 3-6 times (2 bits of repeat count) */
56 : :
57 : : #define REPZ_3_10 17
58 : : /* repeat a zero length 3-10 times (3 bits of repeat count) */
59 : :
60 : : #define REPZ_11_138 18
61 : : /* repeat a zero length 11-138 times (7 bits of repeat count) */
62 : :
63 : : static const int extra_lbits[LENGTH_CODES] /* extra bits for each length code */
64 : : = {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};
65 : :
66 : : static const int extra_dbits[D_CODES] /* extra bits for each distance code */
67 : : = {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};
68 : :
69 : : static const int extra_blbits[BL_CODES]/* extra bits for each bit length code */
70 : : = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7};
71 : :
72 : : static const uch bl_order[BL_CODES]
73 : : = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15};
74 : : /* The lengths of the bit length codes are sent in order of decreasing
75 : : * probability, to avoid transmitting the lengths for unused bit length codes.
76 : : */
77 : :
78 : : #define Buf_size (8 * 2*sizeof(char))
79 : : /* Number of bits used within bi_buf. (bi_buf might be implemented on
80 : : * more than 16 bits on some systems.)
81 : : */
82 : :
83 : : /* ===========================================================================
84 : : * Local data. These are initialized only once.
85 : : */
86 : :
87 : : static ct_data static_ltree[L_CODES+2];
88 : : /* The static literal tree. Since the bit lengths are imposed, there is no
89 : : * need for the L_CODES extra codes used during heap construction. However
90 : : * The codes 286 and 287 are needed to build a canonical tree (see zlib_tr_init
91 : : * below).
92 : : */
93 : :
94 : : static ct_data static_dtree[D_CODES];
95 : : /* The static distance tree. (Actually a trivial tree since all codes use
96 : : * 5 bits.)
97 : : */
98 : :
99 : : static uch dist_code[512];
100 : : /* distance codes. The first 256 values correspond to the distances
101 : : * 3 .. 258, the last 256 values correspond to the top 8 bits of
102 : : * the 15 bit distances.
103 : : */
104 : :
105 : : static uch length_code[MAX_MATCH-MIN_MATCH+1];
106 : : /* length code for each normalized match length (0 == MIN_MATCH) */
107 : :
108 : : static int base_length[LENGTH_CODES];
109 : : /* First normalized length for each code (0 = MIN_MATCH) */
110 : :
111 : : static int base_dist[D_CODES];
112 : : /* First normalized distance for each code (0 = distance of 1) */
113 : :
114 : : struct static_tree_desc_s {
115 : : const ct_data *static_tree; /* static tree or NULL */
116 : : const int *extra_bits; /* extra bits for each code or NULL */
117 : : int extra_base; /* base index for extra_bits */
118 : : int elems; /* max number of elements in the tree */
119 : : int max_length; /* max bit length for the codes */
120 : : };
121 : :
122 : : static static_tree_desc static_l_desc =
123 : : {static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS};
124 : :
125 : : static static_tree_desc static_d_desc =
126 : : {static_dtree, extra_dbits, 0, D_CODES, MAX_BITS};
127 : :
128 : : static static_tree_desc static_bl_desc =
129 : : {(const ct_data *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS};
130 : :
131 : : /* ===========================================================================
132 : : * Local (static) routines in this file.
133 : : */
134 : :
135 : : static void tr_static_init (void);
136 : : static void init_block (deflate_state *s);
137 : : static void pqdownheap (deflate_state *s, ct_data *tree, int k);
138 : : static void gen_bitlen (deflate_state *s, tree_desc *desc);
139 : : static void gen_codes (ct_data *tree, int max_code, ush *bl_count);
140 : : static void build_tree (deflate_state *s, tree_desc *desc);
141 : : static void scan_tree (deflate_state *s, ct_data *tree, int max_code);
142 : : static void send_tree (deflate_state *s, ct_data *tree, int max_code);
143 : : static int build_bl_tree (deflate_state *s);
144 : : static void send_all_trees (deflate_state *s, int lcodes, int dcodes,
145 : : int blcodes);
146 : : static void compress_block (deflate_state *s, ct_data *ltree,
147 : : ct_data *dtree);
148 : : static void set_data_type (deflate_state *s);
149 : : static unsigned bi_reverse (unsigned value, int length);
150 : : static void bi_windup (deflate_state *s);
151 : : static void bi_flush (deflate_state *s);
152 : : static void copy_block (deflate_state *s, char *buf, unsigned len,
153 : : int header);
154 : :
155 : : #ifndef DEBUG_ZLIB
156 : : # define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len)
157 : : /* Send a code of the given tree. c and tree must not have side effects */
158 : :
159 : : #else /* DEBUG_ZLIB */
160 : : # define send_code(s, c, tree) \
161 : : { if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \
162 : : send_bits(s, tree[c].Code, tree[c].Len); }
163 : : #endif
164 : :
165 : : #define d_code(dist) \
166 : : ((dist) < 256 ? dist_code[dist] : dist_code[256+((dist)>>7)])
167 : : /* Mapping from a distance to a distance code. dist is the distance - 1 and
168 : : * must not have side effects. dist_code[256] and dist_code[257] are never
169 : : * used.
170 : : */
171 : :
172 : : /* ===========================================================================
173 : : * Send a value on a given number of bits.
174 : : * IN assertion: length <= 16 and value fits in length bits.
175 : : */
176 : : #ifdef DEBUG_ZLIB
177 : : static void send_bits (deflate_state *s, int value, int length);
178 : :
179 : : static void send_bits(
180 : : deflate_state *s,
181 : : int value, /* value to send */
182 : : int length /* number of bits */
183 : : )
184 : : {
185 : : Tracevv((stderr," l %2d v %4x ", length, value));
186 : : Assert(length > 0 && length <= 15, "invalid length");
187 : : s->bits_sent += (ulg)length;
188 : :
189 : : /* If not enough room in bi_buf, use (valid) bits from bi_buf and
190 : : * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid))
191 : : * unused bits in value.
192 : : */
193 : : if (s->bi_valid > (int)Buf_size - length) {
194 : : s->bi_buf |= (value << s->bi_valid);
195 : : put_short(s, s->bi_buf);
196 : : s->bi_buf = (ush)value >> (Buf_size - s->bi_valid);
197 : : s->bi_valid += length - Buf_size;
198 : : } else {
199 : : s->bi_buf |= value << s->bi_valid;
200 : : s->bi_valid += length;
201 : : }
202 : : }
203 : : #else /* !DEBUG_ZLIB */
204 : :
205 : : #define send_bits(s, value, length) \
206 : : { int len = length;\
207 : : if (s->bi_valid > (int)Buf_size - len) {\
208 : : int val = value;\
209 : : s->bi_buf |= (val << s->bi_valid);\
210 : : put_short(s, s->bi_buf);\
211 : : s->bi_buf = (ush)val >> (Buf_size - s->bi_valid);\
212 : : s->bi_valid += len - Buf_size;\
213 : : } else {\
214 : : s->bi_buf |= (value) << s->bi_valid;\
215 : : s->bi_valid += len;\
216 : : }\
217 : : }
218 : : #endif /* DEBUG_ZLIB */
219 : :
220 : : /* ===========================================================================
221 : : * Initialize the various 'constant' tables. In a multi-threaded environment,
222 : : * this function may be called by two threads concurrently, but this is
223 : : * harmless since both invocations do exactly the same thing.
224 : : */
225 : 0 : static void tr_static_init(void)
226 : : {
227 : : static int static_init_done;
228 : : int n; /* iterates over tree elements */
229 : : int bits; /* bit counter */
230 : : int length; /* length value */
231 : : int code; /* code value */
232 : : int dist; /* distance index */
233 : : ush bl_count[MAX_BITS+1];
234 : : /* number of codes at each bit length for an optimal tree */
235 : :
236 [ # # ]: 0 : if (static_init_done) return;
237 : :
238 : : /* Initialize the mapping length (0..255) -> length code (0..28) */
239 : : length = 0;
240 [ # # ]: 0 : for (code = 0; code < LENGTH_CODES-1; code++) {
241 : 0 : base_length[code] = length;
242 [ # # ]: 0 : for (n = 0; n < (1<<extra_lbits[code]); n++) {
243 : 0 : length_code[length++] = (uch)code;
244 : : }
245 : : }
246 : : Assert (length == 256, "tr_static_init: length != 256");
247 : : /* Note that the length 255 (match length 258) can be represented
248 : : * in two different ways: code 284 + 5 bits or code 285, so we
249 : : * overwrite length_code[255] to use the best encoding:
250 : : */
251 : 0 : length_code[length-1] = (uch)code;
252 : :
253 : : /* Initialize the mapping dist (0..32K) -> dist code (0..29) */
254 : : dist = 0;
255 [ # # ]: 0 : for (code = 0 ; code < 16; code++) {
256 : 0 : base_dist[code] = dist;
257 [ # # ]: 0 : for (n = 0; n < (1<<extra_dbits[code]); n++) {
258 : 0 : dist_code[dist++] = (uch)code;
259 : : }
260 : : }
261 : : Assert (dist == 256, "tr_static_init: dist != 256");
262 : 0 : dist >>= 7; /* from now on, all distances are divided by 128 */
263 [ # # ]: 0 : for ( ; code < D_CODES; code++) {
264 : 0 : base_dist[code] = dist << 7;
265 [ # # ]: 0 : for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) {
266 : 0 : dist_code[256 + dist++] = (uch)code;
267 : : }
268 : : }
269 : : Assert (dist == 256, "tr_static_init: 256+dist != 512");
270 : :
271 : : /* Construct the codes of the static literal tree */
272 [ # # ]: 0 : for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0;
273 : : n = 0;
274 [ # # ]: 0 : while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++;
275 [ # # ]: 0 : while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++;
276 [ # # ]: 0 : while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++;
277 [ # # ]: 0 : while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++;
278 : : /* Codes 286 and 287 do not exist, but we must include them in the
279 : : * tree construction to get a canonical Huffman tree (longest code
280 : : * all ones)
281 : : */
282 : 0 : gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count);
283 : :
284 : : /* The static distance tree is trivial: */
285 [ # # ]: 0 : for (n = 0; n < D_CODES; n++) {
286 : 0 : static_dtree[n].Len = 5;
287 : 0 : static_dtree[n].Code = bi_reverse((unsigned)n, 5);
288 : : }
289 : 0 : static_init_done = 1;
290 : : }
291 : :
292 : : /* ===========================================================================
293 : : * Initialize the tree data structures for a new zlib stream.
294 : : */
295 : 0 : void zlib_tr_init(
296 : : deflate_state *s
297 : : )
298 : : {
299 : 0 : tr_static_init();
300 : :
301 : 0 : s->compressed_len = 0L;
302 : :
303 : 0 : s->l_desc.dyn_tree = s->dyn_ltree;
304 : 0 : s->l_desc.stat_desc = &static_l_desc;
305 : :
306 : 0 : s->d_desc.dyn_tree = s->dyn_dtree;
307 : 0 : s->d_desc.stat_desc = &static_d_desc;
308 : :
309 : 0 : s->bl_desc.dyn_tree = s->bl_tree;
310 : 0 : s->bl_desc.stat_desc = &static_bl_desc;
311 : :
312 : 0 : s->bi_buf = 0;
313 : 0 : s->bi_valid = 0;
314 : 0 : s->last_eob_len = 8; /* enough lookahead for inflate */
315 : : #ifdef DEBUG_ZLIB
316 : : s->bits_sent = 0L;
317 : : #endif
318 : :
319 : : /* Initialize the first block of the first file: */
320 : : init_block(s);
321 : 0 : }
322 : :
323 : : /* ===========================================================================
324 : : * Initialize a new block.
325 : : */
326 : : static void init_block(
327 : : deflate_state *s
328 : : )
329 : : {
330 : : int n; /* iterates over tree elements */
331 : :
332 : : /* Initialize the trees. */
333 [ # # ][ # # ]: 0 : for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0;
334 [ # # ][ # # ]: 0 : for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0;
335 [ # # ][ # # ]: 0 : for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0;
336 : :
337 : 0 : s->dyn_ltree[END_BLOCK].Freq = 1;
338 : 0 : s->opt_len = s->static_len = 0L;
339 : 0 : s->last_lit = s->matches = 0;
340 : : }
341 : :
342 : : #define SMALLEST 1
343 : : /* Index within the heap array of least frequent node in the Huffman tree */
344 : :
345 : :
346 : : /* ===========================================================================
347 : : * Remove the smallest element from the heap and recreate the heap with
348 : : * one less element. Updates heap and heap_len.
349 : : */
350 : : #define pqremove(s, tree, top) \
351 : : {\
352 : : top = s->heap[SMALLEST]; \
353 : : s->heap[SMALLEST] = s->heap[s->heap_len--]; \
354 : : pqdownheap(s, tree, SMALLEST); \
355 : : }
356 : :
357 : : /* ===========================================================================
358 : : * Compares to subtrees, using the tree depth as tie breaker when
359 : : * the subtrees have equal frequency. This minimizes the worst case length.
360 : : */
361 : : #define smaller(tree, n, m, depth) \
362 : : (tree[n].Freq < tree[m].Freq || \
363 : : (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m]))
364 : :
365 : : /* ===========================================================================
366 : : * Restore the heap property by moving down the tree starting at node k,
367 : : * exchanging a node with the smallest of its two sons if necessary, stopping
368 : : * when the heap property is re-established (each father smaller than its
369 : : * two sons).
370 : : */
371 : 0 : static void pqdownheap(
372 : : deflate_state *s,
373 : : ct_data *tree, /* the tree to restore */
374 : : int k /* node to move down */
375 : : )
376 : : {
377 : 0 : int v = s->heap[k];
378 : 0 : int j = k << 1; /* left son of k */
379 [ # # ]: 0 : while (j <= s->heap_len) {
380 : : /* Set j to the smallest of the two sons: */
381 [ # # ][ # # ]: 0 : if (j < s->heap_len &&
382 [ # # ][ # # ]: 0 : smaller(tree, s->heap[j+1], s->heap[j], s->depth)) {
383 : : j++;
384 : : }
385 : : /* Exit if v is smaller than both sons */
386 [ # # ][ # # ]: 0 : if (smaller(tree, v, s->heap[j], s->depth)) break;
[ # # ]
387 : :
388 : : /* Exchange v with the smallest son */
389 : 0 : s->heap[k] = s->heap[j]; k = j;
390 : :
391 : : /* And continue down the tree, setting j to the left son of k */
392 : 0 : j <<= 1;
393 : : }
394 : 0 : s->heap[k] = v;
395 : 0 : }
396 : :
397 : : /* ===========================================================================
398 : : * Compute the optimal bit lengths for a tree and update the total bit length
399 : : * for the current block.
400 : : * IN assertion: the fields freq and dad are set, heap[heap_max] and
401 : : * above are the tree nodes sorted by increasing frequency.
402 : : * OUT assertions: the field len is set to the optimal bit length, the
403 : : * array bl_count contains the frequencies for each bit length.
404 : : * The length opt_len is updated; static_len is also updated if stree is
405 : : * not null.
406 : : */
407 : 0 : static void gen_bitlen(
408 : : deflate_state *s,
409 : : tree_desc *desc /* the tree descriptor */
410 : : )
411 : : {
412 : 0 : ct_data *tree = desc->dyn_tree;
413 : 0 : int max_code = desc->max_code;
414 : 0 : const ct_data *stree = desc->stat_desc->static_tree;
415 : 0 : const int *extra = desc->stat_desc->extra_bits;
416 : 0 : int base = desc->stat_desc->extra_base;
417 : 0 : int max_length = desc->stat_desc->max_length;
418 : : int h; /* heap index */
419 : : int n, m; /* iterate over the tree elements */
420 : : int bits; /* bit length */
421 : : int xbits; /* extra bits */
422 : : ush f; /* frequency */
423 : : int overflow = 0; /* number of elements with bit length too large */
424 : :
425 [ # # ]: 0 : for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0;
426 : :
427 : : /* In a first pass, compute the optimal bit lengths (which may
428 : : * overflow in the case of the bit length tree).
429 : : */
430 : 0 : tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */
431 : :
432 [ # # ]: 0 : for (h = s->heap_max+1; h < HEAP_SIZE; h++) {
433 : 0 : n = s->heap[h];
434 : 0 : bits = tree[tree[n].Dad].Len + 1;
435 [ # # ]: 0 : if (bits > max_length) bits = max_length, overflow++;
436 : 0 : tree[n].Len = (ush)bits;
437 : : /* We overwrite tree[n].Dad which is no longer needed */
438 : :
439 [ # # ]: 0 : if (n > max_code) continue; /* not a leaf node */
440 : :
441 : 0 : s->bl_count[bits]++;
442 : : xbits = 0;
443 [ # # ]: 0 : if (n >= base) xbits = extra[n-base];
444 : 0 : f = tree[n].Freq;
445 : 0 : s->opt_len += (ulg)f * (bits + xbits);
446 [ # # ]: 0 : if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits);
447 : : }
448 [ # # ]: 0 : if (overflow == 0) return;
449 : :
450 : : Trace((stderr,"\nbit length overflow\n"));
451 : : /* This happens for example on obj2 and pic of the Calgary corpus */
452 : :
453 : : /* Find the first bit length which could increase: */
454 : : do {
455 : 0 : bits = max_length-1;
456 [ # # ]: 0 : while (s->bl_count[bits] == 0) bits--;
457 : 0 : s->bl_count[bits]--; /* move one leaf down the tree */
458 : 0 : s->bl_count[bits+1] += 2; /* move one overflow item as its brother */
459 : 0 : s->bl_count[max_length]--;
460 : : /* The brother of the overflow item also moves one step up,
461 : : * but this does not affect bl_count[max_length]
462 : : */
463 : 0 : overflow -= 2;
464 [ # # ]: 0 : } while (overflow > 0);
465 : :
466 : : /* Now recompute all bit lengths, scanning in increasing frequency.
467 : : * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all
468 : : * lengths instead of fixing only the wrong ones. This idea is taken
469 : : * from 'ar' written by Haruhiko Okumura.)
470 : : */
471 [ # # ]: 0 : for (bits = max_length; bits != 0; bits--) {
472 : 0 : n = s->bl_count[bits];
473 [ # # ]: 0 : while (n != 0) {
474 : 0 : m = s->heap[--h];
475 [ # # ]: 0 : if (m > max_code) continue;
476 [ # # ]: 0 : if (tree[m].Len != (unsigned) bits) {
477 : : Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits));
478 : 0 : s->opt_len += ((long)bits - (long)tree[m].Len)
479 : 0 : *(long)tree[m].Freq;
480 : 0 : tree[m].Len = (ush)bits;
481 : : }
482 : 0 : n--;
483 : : }
484 : : }
485 : : }
486 : :
487 : : /* ===========================================================================
488 : : * Generate the codes for a given tree and bit counts (which need not be
489 : : * optimal).
490 : : * IN assertion: the array bl_count contains the bit length statistics for
491 : : * the given tree and the field len is set for all tree elements.
492 : : * OUT assertion: the field code is set for all tree elements of non
493 : : * zero code length.
494 : : */
495 : 0 : static void gen_codes(
496 : : ct_data *tree, /* the tree to decorate */
497 : : int max_code, /* largest code with non zero frequency */
498 : : ush *bl_count /* number of codes at each bit length */
499 : : )
500 : : {
501 : : ush next_code[MAX_BITS+1]; /* next code value for each bit length */
502 : : ush code = 0; /* running code value */
503 : : int bits; /* bit index */
504 : : int n; /* code index */
505 : :
506 : : /* The distribution counts are first used to generate the code values
507 : : * without bit reversal.
508 : : */
509 [ # # ]: 0 : for (bits = 1; bits <= MAX_BITS; bits++) {
510 : 0 : next_code[bits] = code = (code + bl_count[bits-1]) << 1;
511 : : }
512 : : /* Check that the bit counts in bl_count are consistent. The last code
513 : : * must be all ones.
514 : : */
515 : : Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1,
516 : : "inconsistent bit counts");
517 : : Tracev((stderr,"\ngen_codes: max_code %d ", max_code));
518 : :
519 [ # # ]: 0 : for (n = 0; n <= max_code; n++) {
520 : 0 : int len = tree[n].Len;
521 [ # # ]: 0 : if (len == 0) continue;
522 : : /* Now reverse the bits */
523 : 0 : tree[n].Code = bi_reverse(next_code[len]++, len);
524 : :
525 : : Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ",
526 : : n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1));
527 : : }
528 : 0 : }
529 : :
530 : : /* ===========================================================================
531 : : * Construct one Huffman tree and assigns the code bit strings and lengths.
532 : : * Update the total bit length for the current block.
533 : : * IN assertion: the field freq is set for all tree elements.
534 : : * OUT assertions: the fields len and code are set to the optimal bit length
535 : : * and corresponding code. The length opt_len is updated; static_len is
536 : : * also updated if stree is not null. The field max_code is set.
537 : : */
538 : 0 : static void build_tree(
539 : : deflate_state *s,
540 : : tree_desc *desc /* the tree descriptor */
541 : : )
542 : : {
543 : 0 : ct_data *tree = desc->dyn_tree;
544 : 0 : const ct_data *stree = desc->stat_desc->static_tree;
545 : 0 : int elems = desc->stat_desc->elems;
546 : : int n, m; /* iterate over heap elements */
547 : : int max_code = -1; /* largest code with non zero frequency */
548 : : int node; /* new node being created */
549 : :
550 : : /* Construct the initial heap, with least frequent element in
551 : : * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1].
552 : : * heap[0] is not used.
553 : : */
554 : 0 : s->heap_len = 0, s->heap_max = HEAP_SIZE;
555 : :
556 [ # # ]: 0 : for (n = 0; n < elems; n++) {
557 [ # # ]: 0 : if (tree[n].Freq != 0) {
558 : 0 : s->heap[++(s->heap_len)] = max_code = n;
559 : 0 : s->depth[n] = 0;
560 : : } else {
561 : 0 : tree[n].Len = 0;
562 : : }
563 : : }
564 : :
565 : : /* The pkzip format requires that at least one distance code exists,
566 : : * and that at least one bit should be sent even if there is only one
567 : : * possible code. So to avoid special checks later on we force at least
568 : : * two codes of non zero frequency.
569 : : */
570 [ # # ]: 0 : while (s->heap_len < 2) {
571 [ # # ]: 0 : node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0);
572 : 0 : tree[node].Freq = 1;
573 : 0 : s->depth[node] = 0;
574 [ # # ]: 0 : s->opt_len--; if (stree) s->static_len -= stree[node].Len;
575 : : /* node is 0 or 1 so it does not have extra bits */
576 : : }
577 : 0 : desc->max_code = max_code;
578 : :
579 : : /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree,
580 : : * establish sub-heaps of increasing lengths:
581 : : */
582 [ # # ]: 0 : for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, n);
583 : :
584 : : /* Construct the Huffman tree by repeatedly combining the least two
585 : : * frequent nodes.
586 : : */
587 : : node = elems; /* next internal node of the tree */
588 : : do {
589 : 0 : pqremove(s, tree, n); /* n = node of least frequency */
590 : 0 : m = s->heap[SMALLEST]; /* m = node of next least frequency */
591 : :
592 : 0 : s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */
593 : 0 : s->heap[--(s->heap_max)] = m;
594 : :
595 : : /* Create a new node father of n and m */
596 : 0 : tree[node].Freq = tree[n].Freq + tree[m].Freq;
597 : 0 : s->depth[node] = (uch) (max(s->depth[n], s->depth[m]) + 1);
598 : 0 : tree[n].Dad = tree[m].Dad = (ush)node;
599 : : #ifdef DUMP_BL_TREE
600 : : if (tree == s->bl_tree) {
601 : : fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)",
602 : : node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq);
603 : : }
604 : : #endif
605 : : /* and insert the new node in the heap */
606 : 0 : s->heap[SMALLEST] = node++;
607 : 0 : pqdownheap(s, tree, SMALLEST);
608 : :
609 [ # # ]: 0 : } while (s->heap_len >= 2);
610 : :
611 : 0 : s->heap[--(s->heap_max)] = s->heap[SMALLEST];
612 : :
613 : : /* At this point, the fields freq and dad are set. We can now
614 : : * generate the bit lengths.
615 : : */
616 : 0 : gen_bitlen(s, (tree_desc *)desc);
617 : :
618 : : /* The field len is now set, we can generate the bit codes */
619 : 0 : gen_codes ((ct_data *)tree, max_code, s->bl_count);
620 : 0 : }
621 : :
622 : : /* ===========================================================================
623 : : * Scan a literal or distance tree to determine the frequencies of the codes
624 : : * in the bit length tree.
625 : : */
626 : 0 : static void scan_tree(
627 : : deflate_state *s,
628 : : ct_data *tree, /* the tree to be scanned */
629 : : int max_code /* and its largest code of non zero frequency */
630 : : )
631 : : {
632 : : int n; /* iterates over all tree elements */
633 : : int prevlen = -1; /* last emitted length */
634 : : int curlen; /* length of current code */
635 : 0 : int nextlen = tree[0].Len; /* length of next code */
636 : : int count = 0; /* repeat count of the current code */
637 : : int max_count = 7; /* max repeat count */
638 : : int min_count = 4; /* min repeat count */
639 : :
640 [ # # ]: 0 : if (nextlen == 0) max_count = 138, min_count = 3;
641 : 0 : tree[max_code+1].Len = (ush)0xffff; /* guard */
642 : :
643 [ # # ]: 0 : for (n = 0; n <= max_code; n++) {
644 : 0 : curlen = nextlen; nextlen = tree[n+1].Len;
645 [ # # ][ # # ]: 0 : if (++count < max_count && curlen == nextlen) {
646 : 0 : continue;
647 [ # # ]: 0 : } else if (count < min_count) {
648 : 0 : s->bl_tree[curlen].Freq += count;
649 [ # # ]: 0 : } else if (curlen != 0) {
650 [ # # ]: 0 : if (curlen != prevlen) s->bl_tree[curlen].Freq++;
651 : 0 : s->bl_tree[REP_3_6].Freq++;
652 [ # # ]: 0 : } else if (count <= 10) {
653 : 0 : s->bl_tree[REPZ_3_10].Freq++;
654 : : } else {
655 : 0 : s->bl_tree[REPZ_11_138].Freq++;
656 : : }
657 : : count = 0; prevlen = curlen;
658 [ # # ]: 0 : if (nextlen == 0) {
659 : : max_count = 138, min_count = 3;
660 [ # # ]: 0 : } else if (curlen == nextlen) {
661 : : max_count = 6, min_count = 3;
662 : : } else {
663 : : max_count = 7, min_count = 4;
664 : : }
665 : : }
666 : 0 : }
667 : :
668 : : /* ===========================================================================
669 : : * Send a literal or distance tree in compressed form, using the codes in
670 : : * bl_tree.
671 : : */
672 : 0 : static void send_tree(
673 : : deflate_state *s,
674 : : ct_data *tree, /* the tree to be scanned */
675 : : int max_code /* and its largest code of non zero frequency */
676 : : )
677 : : {
678 : : int n; /* iterates over all tree elements */
679 : : int prevlen = -1; /* last emitted length */
680 : : int curlen; /* length of current code */
681 : 0 : int nextlen = tree[0].Len; /* length of next code */
682 : : int count = 0; /* repeat count of the current code */
683 : : int max_count = 7; /* max repeat count */
684 : : int min_count = 4; /* min repeat count */
685 : :
686 : : /* tree[max_code+1].Len = -1; */ /* guard already set */
687 [ # # ]: 0 : if (nextlen == 0) max_count = 138, min_count = 3;
688 : :
689 [ # # ]: 0 : for (n = 0; n <= max_code; n++) {
690 : 0 : curlen = nextlen; nextlen = tree[n+1].Len;
691 [ # # ][ # # ]: 0 : if (++count < max_count && curlen == nextlen) {
692 : 0 : continue;
693 [ # # ]: 0 : } else if (count < min_count) {
694 [ # # ][ # # ]: 0 : do { send_code(s, curlen, s->bl_tree); } while (--count != 0);
695 : :
696 [ # # ]: 0 : } else if (curlen != 0) {
697 [ # # ]: 0 : if (curlen != prevlen) {
698 [ # # ]: 0 : send_code(s, curlen, s->bl_tree); count--;
699 : : }
700 : : Assert(count >= 3 && count <= 6, " 3_6?");
701 [ # # ][ # # ]: 0 : send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2);
702 : :
703 [ # # ]: 0 : } else if (count <= 10) {
704 [ # # ][ # # ]: 0 : send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3);
705 : :
706 : : } else {
707 [ # # ][ # # ]: 0 : send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7);
708 : : }
709 : : count = 0; prevlen = curlen;
710 [ # # ]: 0 : if (nextlen == 0) {
711 : : max_count = 138, min_count = 3;
712 [ # # ]: 0 : } else if (curlen == nextlen) {
713 : : max_count = 6, min_count = 3;
714 : : } else {
715 : : max_count = 7, min_count = 4;
716 : : }
717 : : }
718 : 0 : }
719 : :
720 : : /* ===========================================================================
721 : : * Construct the Huffman tree for the bit lengths and return the index in
722 : : * bl_order of the last bit length code to send.
723 : : */
724 : 0 : static int build_bl_tree(
725 : : deflate_state *s
726 : : )
727 : : {
728 : : int max_blindex; /* index of last bit length code of non zero freq */
729 : :
730 : : /* Determine the bit length frequencies for literal and distance trees */
731 : 0 : scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code);
732 : 0 : scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code);
733 : :
734 : : /* Build the bit length tree: */
735 : 0 : build_tree(s, (tree_desc *)(&(s->bl_desc)));
736 : : /* opt_len now includes the length of the tree representations, except
737 : : * the lengths of the bit lengths codes and the 5+5+4 bits for the counts.
738 : : */
739 : :
740 : : /* Determine the number of bit length codes to send. The pkzip format
741 : : * requires that at least 4 bit length codes be sent. (appnote.txt says
742 : : * 3 but the actual value used is 4.)
743 : : */
744 [ # # ]: 0 : for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) {
745 [ # # ]: 0 : if (s->bl_tree[bl_order[max_blindex]].Len != 0) break;
746 : : }
747 : : /* Update opt_len to include the bit length tree and counts */
748 : 0 : s->opt_len += 3*(max_blindex+1) + 5+5+4;
749 : : Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld",
750 : : s->opt_len, s->static_len));
751 : :
752 : 0 : return max_blindex;
753 : : }
754 : :
755 : : /* ===========================================================================
756 : : * Send the header for a block using dynamic Huffman trees: the counts, the
757 : : * lengths of the bit length codes, the literal tree and the distance tree.
758 : : * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.
759 : : */
760 : 0 : static void send_all_trees(
761 : : deflate_state *s,
762 : : int lcodes, /* number of codes for each tree */
763 : : int dcodes, /* number of codes for each tree */
764 : : int blcodes /* number of codes for each tree */
765 : : )
766 : : {
767 : : int rank; /* index in bl_order */
768 : :
769 : : Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes");
770 : : Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES,
771 : : "too many codes");
772 : : Tracev((stderr, "\nbl counts: "));
773 [ # # ]: 0 : send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */
774 [ # # ]: 0 : send_bits(s, dcodes-1, 5);
775 [ # # ]: 0 : send_bits(s, blcodes-4, 4); /* not -3 as stated in appnote.txt */
776 [ # # ]: 0 : for (rank = 0; rank < blcodes; rank++) {
777 : : Tracev((stderr, "\nbl code %2d ", bl_order[rank]));
778 [ # # ]: 0 : send_bits(s, s->bl_tree[bl_order[rank]].Len, 3);
779 : : }
780 : : Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent));
781 : :
782 : 0 : send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */
783 : : Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent));
784 : :
785 : 0 : send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */
786 : : Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent));
787 : 0 : }
788 : :
789 : : /* ===========================================================================
790 : : * Send a stored block
791 : : */
792 : 0 : void zlib_tr_stored_block(
793 : : deflate_state *s,
794 : : char *buf, /* input block */
795 : : ulg stored_len, /* length of input block */
796 : : int eof /* true if this is the last block for a file */
797 : : )
798 : : {
799 [ # # ]: 0 : send_bits(s, (STORED_BLOCK<<1)+eof, 3); /* send block type */
800 : 0 : s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L;
801 : 0 : s->compressed_len += (stored_len + 4) << 3;
802 : :
803 : 0 : copy_block(s, buf, (unsigned)stored_len, 1); /* with header */
804 : 0 : }
805 : :
806 : : /* Send just the `stored block' type code without any length bytes or data.
807 : : */
808 : 0 : void zlib_tr_stored_type_only(
809 : : deflate_state *s
810 : : )
811 : : {
812 [ # # ]: 0 : send_bits(s, (STORED_BLOCK << 1), 3);
813 : : bi_windup(s);
814 : 0 : s->compressed_len = (s->compressed_len + 3) & ~7L;
815 : 0 : }
816 : :
817 : :
818 : : /* ===========================================================================
819 : : * Send one empty static block to give enough lookahead for inflate.
820 : : * This takes 10 bits, of which 7 may remain in the bit buffer.
821 : : * The current inflate code requires 9 bits of lookahead. If the
822 : : * last two codes for the previous block (real code plus EOB) were coded
823 : : * on 5 bits or less, inflate may have only 5+3 bits of lookahead to decode
824 : : * the last real code. In this case we send two empty static blocks instead
825 : : * of one. (There are no problems if the previous block is stored or fixed.)
826 : : * To simplify the code, we assume the worst case of last real code encoded
827 : : * on one bit only.
828 : : */
829 : 0 : void zlib_tr_align(
830 : : deflate_state *s
831 : : )
832 : : {
833 [ # # ]: 0 : send_bits(s, STATIC_TREES<<1, 3);
834 [ # # ]: 0 : send_code(s, END_BLOCK, static_ltree);
835 : 0 : s->compressed_len += 10L; /* 3 for block type, 7 for EOB */
836 : : bi_flush(s);
837 : : /* Of the 10 bits for the empty block, we have already sent
838 : : * (10 - bi_valid) bits. The lookahead for the last real code (before
839 : : * the EOB of the previous block) was thus at least one plus the length
840 : : * of the EOB plus what we have just sent of the empty static block.
841 : : */
842 [ # # ]: 0 : if (1 + s->last_eob_len + 10 - s->bi_valid < 9) {
843 [ # # ]: 0 : send_bits(s, STATIC_TREES<<1, 3);
844 [ # # ]: 0 : send_code(s, END_BLOCK, static_ltree);
845 : 0 : s->compressed_len += 10L;
846 : : bi_flush(s);
847 : : }
848 : 0 : s->last_eob_len = 7;
849 : 0 : }
850 : :
851 : : /* ===========================================================================
852 : : * Determine the best encoding for the current block: dynamic trees, static
853 : : * trees or store, and output the encoded block to the zip file. This function
854 : : * returns the total compressed length for the file so far.
855 : : */
856 : 0 : ulg zlib_tr_flush_block(
857 : : deflate_state *s,
858 : : char *buf, /* input block, or NULL if too old */
859 : : ulg stored_len, /* length of input block */
860 : : int eof /* true if this is the last block for a file */
861 : : )
862 : : {
863 : : ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */
864 : : int max_blindex = 0; /* index of last bit length code of non zero freq */
865 : :
866 : : /* Build the Huffman trees unless a stored block is forced */
867 [ # # ]: 0 : if (s->level > 0) {
868 : :
869 : : /* Check if the file is ascii or binary */
870 [ # # ]: 0 : if (s->data_type == Z_UNKNOWN) set_data_type(s);
871 : :
872 : : /* Construct the literal and distance trees */
873 : 0 : build_tree(s, (tree_desc *)(&(s->l_desc)));
874 : : Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len,
875 : : s->static_len));
876 : :
877 : 0 : build_tree(s, (tree_desc *)(&(s->d_desc)));
878 : : Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len,
879 : : s->static_len));
880 : : /* At this point, opt_len and static_len are the total bit lengths of
881 : : * the compressed block data, excluding the tree representations.
882 : : */
883 : :
884 : : /* Build the bit length tree for the above two trees, and get the index
885 : : * in bl_order of the last bit length code to send.
886 : : */
887 : 0 : max_blindex = build_bl_tree(s);
888 : :
889 : : /* Determine the best encoding. Compute first the block length in bytes*/
890 : 0 : opt_lenb = (s->opt_len+3+7)>>3;
891 : 0 : static_lenb = (s->static_len+3+7)>>3;
892 : :
893 : : Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ",
894 : : opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len,
895 : : s->last_lit));
896 : :
897 [ # # ]: 0 : if (static_lenb <= opt_lenb) opt_lenb = static_lenb;
898 : :
899 : : } else {
900 : : Assert(buf != (char*)0, "lost buf");
901 : 0 : opt_lenb = static_lenb = stored_len + 5; /* force a stored block */
902 : : }
903 : :
904 : : /* If compression failed and this is the first and last block,
905 : : * and if the .zip file can be seeked (to rewrite the local header),
906 : : * the whole file is transformed into a stored file:
907 : : */
908 : : #ifdef STORED_FILE_OK
909 : : # ifdef FORCE_STORED_FILE
910 : : if (eof && s->compressed_len == 0L) { /* force stored file */
911 : : # else
912 : : if (stored_len <= opt_lenb && eof && s->compressed_len==0L && seekable()) {
913 : : # endif
914 : : /* Since LIT_BUFSIZE <= 2*WSIZE, the input data must be there: */
915 : : if (buf == (char*)0) error ("block vanished");
916 : :
917 : : copy_block(s, buf, (unsigned)stored_len, 0); /* without header */
918 : : s->compressed_len = stored_len << 3;
919 : : s->method = STORED;
920 : : } else
921 : : #endif /* STORED_FILE_OK */
922 : :
923 : : #ifdef FORCE_STORED
924 : : if (buf != (char*)0) { /* force stored block */
925 : : #else
926 [ # # ][ # # ]: 0 : if (stored_len+4 <= opt_lenb && buf != (char*)0) {
927 : : /* 4: two words for the lengths */
928 : : #endif
929 : : /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.
930 : : * Otherwise we can't have processed more than WSIZE input bytes since
931 : : * the last block flush, because compression would have been
932 : : * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to
933 : : * transform a block into a stored block.
934 : : */
935 : 0 : zlib_tr_stored_block(s, buf, stored_len, eof);
936 : :
937 : : #ifdef FORCE_STATIC
938 : : } else if (static_lenb >= 0) { /* force static trees */
939 : : #else
940 [ # # ]: 0 : } else if (static_lenb == opt_lenb) {
941 : : #endif
942 [ # # ]: 0 : send_bits(s, (STATIC_TREES<<1)+eof, 3);
943 : 0 : compress_block(s, (ct_data *)static_ltree, (ct_data *)static_dtree);
944 : 0 : s->compressed_len += 3 + s->static_len;
945 : : } else {
946 [ # # ]: 0 : send_bits(s, (DYN_TREES<<1)+eof, 3);
947 : 0 : send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1,
948 : : max_blindex+1);
949 : 0 : compress_block(s, (ct_data *)s->dyn_ltree, (ct_data *)s->dyn_dtree);
950 : 0 : s->compressed_len += 3 + s->opt_len;
951 : : }
952 : : Assert (s->compressed_len == s->bits_sent, "bad compressed size");
953 : : init_block(s);
954 : :
955 [ # # ]: 0 : if (eof) {
956 : : bi_windup(s);
957 : 0 : s->compressed_len += 7; /* align on byte boundary */
958 : : }
959 : : Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3,
960 : : s->compressed_len-7*eof));
961 : :
962 : 0 : return s->compressed_len >> 3;
963 : : }
964 : :
965 : : /* ===========================================================================
966 : : * Save the match info and tally the frequency counts. Return true if
967 : : * the current block must be flushed.
968 : : */
969 : 0 : int zlib_tr_tally(
970 : : deflate_state *s,
971 : : unsigned dist, /* distance of matched string */
972 : : unsigned lc /* match length-MIN_MATCH or unmatched char (if dist==0) */
973 : : )
974 : : {
975 : 0 : s->d_buf[s->last_lit] = (ush)dist;
976 : 0 : s->l_buf[s->last_lit++] = (uch)lc;
977 [ # # ]: 0 : if (dist == 0) {
978 : : /* lc is the unmatched char */
979 : 0 : s->dyn_ltree[lc].Freq++;
980 : : } else {
981 : 0 : s->matches++;
982 : : /* Here, lc is the match length - MIN_MATCH */
983 : 0 : dist--; /* dist = match distance - 1 */
984 : : Assert((ush)dist < (ush)MAX_DIST(s) &&
985 : : (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) &&
986 : : (ush)d_code(dist) < (ush)D_CODES, "zlib_tr_tally: bad match");
987 : :
988 : 0 : s->dyn_ltree[length_code[lc]+LITERALS+1].Freq++;
989 [ # # ]: 0 : s->dyn_dtree[d_code(dist)].Freq++;
990 : : }
991 : :
992 : : /* Try to guess if it is profitable to stop the current block here */
993 [ # # ][ # # ]: 0 : if ((s->last_lit & 0xfff) == 0 && s->level > 2) {
994 : : /* Compute an upper bound for the compressed length */
995 : 0 : ulg out_length = (ulg)s->last_lit*8L;
996 : 0 : ulg in_length = (ulg)((long)s->strstart - s->block_start);
997 : : int dcode;
998 [ # # ]: 0 : for (dcode = 0; dcode < D_CODES; dcode++) {
999 : 0 : out_length += (ulg)s->dyn_dtree[dcode].Freq *
1000 : 0 : (5L+extra_dbits[dcode]);
1001 : : }
1002 : 0 : out_length >>= 3;
1003 : : Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ",
1004 : : s->last_lit, in_length, out_length,
1005 : : 100L - out_length*100L/in_length));
1006 [ # # ][ # # ]: 0 : if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1;
1007 : : }
1008 : 0 : return (s->last_lit == s->lit_bufsize-1);
1009 : : /* We avoid equality with lit_bufsize because of wraparound at 64K
1010 : : * on 16 bit machines and because stored blocks are restricted to
1011 : : * 64K-1 bytes.
1012 : : */
1013 : : }
1014 : :
1015 : : /* ===========================================================================
1016 : : * Send the block data compressed using the given Huffman trees
1017 : : */
1018 : 0 : static void compress_block(
1019 : : deflate_state *s,
1020 : : ct_data *ltree, /* literal tree */
1021 : : ct_data *dtree /* distance tree */
1022 : : )
1023 : : {
1024 : : unsigned dist; /* distance of matched string */
1025 : : int lc; /* match length or unmatched char (if dist == 0) */
1026 : : unsigned lx = 0; /* running index in l_buf */
1027 : : unsigned code; /* the code to send */
1028 : : int extra; /* number of extra bits to send */
1029 : :
1030 [ # # ]: 0 : if (s->last_lit != 0) do {
1031 : 0 : dist = s->d_buf[lx];
1032 : 0 : lc = s->l_buf[lx++];
1033 [ # # ]: 0 : if (dist == 0) {
1034 [ # # ]: 0 : send_code(s, lc, ltree); /* send a literal byte */
1035 : : Tracecv(isgraph(lc), (stderr," '%c' ", lc));
1036 : : } else {
1037 : : /* Here, lc is the match length - MIN_MATCH */
1038 : 0 : code = length_code[lc];
1039 [ # # ]: 0 : send_code(s, code+LITERALS+1, ltree); /* send the length code */
1040 : 0 : extra = extra_lbits[code];
1041 [ # # ]: 0 : if (extra != 0) {
1042 : 0 : lc -= base_length[code];
1043 [ # # ]: 0 : send_bits(s, lc, extra); /* send the extra length bits */
1044 : : }
1045 : 0 : dist--; /* dist is now the match distance - 1 */
1046 [ # # ]: 0 : code = d_code(dist);
1047 : : Assert (code < D_CODES, "bad d_code");
1048 : :
1049 [ # # ]: 0 : send_code(s, code, dtree); /* send the distance code */
1050 : 0 : extra = extra_dbits[code];
1051 [ # # ]: 0 : if (extra != 0) {
1052 : 0 : dist -= base_dist[code];
1053 [ # # ]: 0 : send_bits(s, dist, extra); /* send the extra distance bits */
1054 : : }
1055 : : } /* literal or match pair ? */
1056 : :
1057 : : /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */
1058 : : Assert(s->pending < s->lit_bufsize + 2*lx, "pendingBuf overflow");
1059 : :
1060 [ # # ]: 0 : } while (lx < s->last_lit);
1061 : :
1062 [ # # ]: 0 : send_code(s, END_BLOCK, ltree);
1063 : 0 : s->last_eob_len = ltree[END_BLOCK].Len;
1064 : 0 : }
1065 : :
1066 : : /* ===========================================================================
1067 : : * Set the data type to ASCII or BINARY, using a crude approximation:
1068 : : * binary if more than 20% of the bytes are <= 6 or >= 128, ascii otherwise.
1069 : : * IN assertion: the fields freq of dyn_ltree are set and the total of all
1070 : : * frequencies does not exceed 64K (to fit in an int on 16 bit machines).
1071 : : */
1072 : 0 : static void set_data_type(
1073 : : deflate_state *s
1074 : : )
1075 : : {
1076 : : int n = 0;
1077 : : unsigned ascii_freq = 0;
1078 : : unsigned bin_freq = 0;
1079 [ # # ]: 0 : while (n < 7) bin_freq += s->dyn_ltree[n++].Freq;
1080 [ # # ]: 0 : while (n < 128) ascii_freq += s->dyn_ltree[n++].Freq;
1081 [ # # ]: 0 : while (n < LITERALS) bin_freq += s->dyn_ltree[n++].Freq;
1082 : 0 : s->data_type = (Byte)(bin_freq > (ascii_freq >> 2) ? Z_BINARY : Z_ASCII);
1083 : 0 : }
1084 : :
1085 : : /* ===========================================================================
1086 : : * Copy a stored block, storing first the length and its
1087 : : * one's complement if requested.
1088 : : */
1089 : 0 : static void copy_block(
1090 : : deflate_state *s,
1091 : : char *buf, /* the input data */
1092 : : unsigned len, /* its length */
1093 : : int header /* true if block header must be written */
1094 : : )
1095 : : {
1096 : : bi_windup(s); /* align on byte boundary */
1097 : 0 : s->last_eob_len = 8; /* enough lookahead for inflate */
1098 : :
1099 [ # # ]: 0 : if (header) {
1100 : 0 : put_short(s, (ush)len);
1101 : 0 : put_short(s, (ush)~len);
1102 : : #ifdef DEBUG_ZLIB
1103 : : s->bits_sent += 2*16;
1104 : : #endif
1105 : : }
1106 : : #ifdef DEBUG_ZLIB
1107 : : s->bits_sent += (ulg)len<<3;
1108 : : #endif
1109 : : /* bundle up the put_byte(s, *buf++) calls */
1110 : 0 : memcpy(&s->pending_buf[s->pending], buf, len);
1111 : 0 : s->pending += len;
1112 : 0 : }
1113 : :
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