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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 <linux/bitrev.h>
39 : : #include "defutil.h"
40 : :
41 : : #ifdef DEBUG_ZLIB
42 : : # include <ctype.h>
43 : : #endif
44 : :
45 : : /* ===========================================================================
46 : : * Constants
47 : : */
48 : :
49 : : #define MAX_BL_BITS 7
50 : : /* Bit length codes must not exceed MAX_BL_BITS bits */
51 : :
52 : : #define END_BLOCK 256
53 : : /* end of block literal code */
54 : :
55 : : #define REP_3_6 16
56 : : /* repeat previous bit length 3-6 times (2 bits of repeat count) */
57 : :
58 : : #define REPZ_3_10 17
59 : : /* repeat a zero length 3-10 times (3 bits of repeat count) */
60 : :
61 : : #define REPZ_11_138 18
62 : : /* repeat a zero length 11-138 times (7 bits of repeat count) */
63 : :
64 : : static const int extra_lbits[LENGTH_CODES] /* extra bits for each length code */
65 : : = {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};
66 : :
67 : : static const int extra_dbits[D_CODES] /* extra bits for each distance code */
68 : : = {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};
69 : :
70 : : static const int extra_blbits[BL_CODES]/* extra bits for each bit length code */
71 : : = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7};
72 : :
73 : : static const uch bl_order[BL_CODES]
74 : : = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15};
75 : : /* The lengths of the bit length codes are sent in order of decreasing
76 : : * probability, to avoid transmitting the lengths for unused bit length codes.
77 : : */
78 : :
79 : : /* ===========================================================================
80 : : * Local data. These are initialized only once.
81 : : */
82 : :
83 : : static ct_data static_ltree[L_CODES+2];
84 : : /* The static literal tree. Since the bit lengths are imposed, there is no
85 : : * need for the L_CODES extra codes used during heap construction. However
86 : : * The codes 286 and 287 are needed to build a canonical tree (see zlib_tr_init
87 : : * below).
88 : : */
89 : :
90 : : static ct_data static_dtree[D_CODES];
91 : : /* The static distance tree. (Actually a trivial tree since all codes use
92 : : * 5 bits.)
93 : : */
94 : :
95 : : static uch dist_code[512];
96 : : /* distance codes. The first 256 values correspond to the distances
97 : : * 3 .. 258, the last 256 values correspond to the top 8 bits of
98 : : * the 15 bit distances.
99 : : */
100 : :
101 : : static uch length_code[MAX_MATCH-MIN_MATCH+1];
102 : : /* length code for each normalized match length (0 == MIN_MATCH) */
103 : :
104 : : static int base_length[LENGTH_CODES];
105 : : /* First normalized length for each code (0 = MIN_MATCH) */
106 : :
107 : : static int base_dist[D_CODES];
108 : : /* First normalized distance for each code (0 = distance of 1) */
109 : :
110 : : struct static_tree_desc_s {
111 : : const ct_data *static_tree; /* static tree or NULL */
112 : : const int *extra_bits; /* extra bits for each code or NULL */
113 : : int extra_base; /* base index for extra_bits */
114 : : int elems; /* max number of elements in the tree */
115 : : int max_length; /* max bit length for the codes */
116 : : };
117 : :
118 : : static static_tree_desc static_l_desc =
119 : : {static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS};
120 : :
121 : : static static_tree_desc static_d_desc =
122 : : {static_dtree, extra_dbits, 0, D_CODES, MAX_BITS};
123 : :
124 : : static static_tree_desc static_bl_desc =
125 : : {(const ct_data *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS};
126 : :
127 : : /* ===========================================================================
128 : : * Local (static) routines in this file.
129 : : */
130 : :
131 : : static void tr_static_init (void);
132 : : static void init_block (deflate_state *s);
133 : : static void pqdownheap (deflate_state *s, ct_data *tree, int k);
134 : : static void gen_bitlen (deflate_state *s, tree_desc *desc);
135 : : static void gen_codes (ct_data *tree, int max_code, ush *bl_count);
136 : : static void build_tree (deflate_state *s, tree_desc *desc);
137 : : static void scan_tree (deflate_state *s, ct_data *tree, int max_code);
138 : : static void send_tree (deflate_state *s, ct_data *tree, int max_code);
139 : : static int build_bl_tree (deflate_state *s);
140 : : static void send_all_trees (deflate_state *s, int lcodes, int dcodes,
141 : : int blcodes);
142 : : static void compress_block (deflate_state *s, ct_data *ltree,
143 : : ct_data *dtree);
144 : : static void set_data_type (deflate_state *s);
145 : : static void bi_flush (deflate_state *s);
146 : : static void copy_block (deflate_state *s, char *buf, unsigned len,
147 : : int header);
148 : :
149 : : #ifndef DEBUG_ZLIB
150 : : # define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len)
151 : : /* Send a code of the given tree. c and tree must not have side effects */
152 : :
153 : : #else /* DEBUG_ZLIB */
154 : : # define send_code(s, c, tree) \
155 : : { if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \
156 : : send_bits(s, tree[c].Code, tree[c].Len); }
157 : : #endif
158 : :
159 : : #define d_code(dist) \
160 : : ((dist) < 256 ? dist_code[dist] : dist_code[256+((dist)>>7)])
161 : : /* Mapping from a distance to a distance code. dist is the distance - 1 and
162 : : * must not have side effects. dist_code[256] and dist_code[257] are never
163 : : * used.
164 : : */
165 : :
166 : : /* ===========================================================================
167 : : * Initialize the various 'constant' tables. In a multi-threaded environment,
168 : : * this function may be called by two threads concurrently, but this is
169 : : * harmless since both invocations do exactly the same thing.
170 : : */
171 : 0 : static void tr_static_init(void)
172 : : {
173 : 0 : static int static_init_done;
174 : 0 : int n; /* iterates over tree elements */
175 : 0 : int bits; /* bit counter */
176 : 0 : int length; /* length value */
177 : 0 : int code; /* code value */
178 : 0 : int dist; /* distance index */
179 : 0 : ush bl_count[MAX_BITS+1];
180 : : /* number of codes at each bit length for an optimal tree */
181 : :
182 [ # # ]: 0 : if (static_init_done) return;
183 : :
184 : : /* Initialize the mapping length (0..255) -> length code (0..28) */
185 : : length = 0;
186 [ # # ]: 0 : for (code = 0; code < LENGTH_CODES-1; code++) {
187 : 0 : base_length[code] = length;
188 [ # # ]: 0 : for (n = 0; n < (1<<extra_lbits[code]); n++) {
189 : 0 : length_code[length++] = (uch)code;
190 : : }
191 : : }
192 : 0 : Assert (length == 256, "tr_static_init: length != 256");
193 : : /* Note that the length 255 (match length 258) can be represented
194 : : * in two different ways: code 284 + 5 bits or code 285, so we
195 : : * overwrite length_code[255] to use the best encoding:
196 : : */
197 : 0 : length_code[length-1] = (uch)code;
198 : :
199 : : /* Initialize the mapping dist (0..32K) -> dist code (0..29) */
200 : 0 : dist = 0;
201 [ # # ]: 0 : for (code = 0 ; code < 16; code++) {
202 : 0 : base_dist[code] = dist;
203 [ # # ]: 0 : for (n = 0; n < (1<<extra_dbits[code]); n++) {
204 : 0 : dist_code[dist++] = (uch)code;
205 : : }
206 : : }
207 : 0 : Assert (dist == 256, "tr_static_init: dist != 256");
208 : 0 : dist >>= 7; /* from now on, all distances are divided by 128 */
209 [ # # ]: 0 : for ( ; code < D_CODES; code++) {
210 : 0 : base_dist[code] = dist << 7;
211 [ # # ]: 0 : for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) {
212 : 0 : dist_code[256 + dist++] = (uch)code;
213 : : }
214 : : }
215 : : Assert (dist == 256, "tr_static_init: 256+dist != 512");
216 : :
217 : : /* Construct the codes of the static literal tree */
218 [ # # ]: 0 : for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0;
219 : : n = 0;
220 [ # # ]: 0 : while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++;
221 [ # # ]: 0 : while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++;
222 [ # # ]: 0 : while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++;
223 [ # # ]: 0 : while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++;
224 : : /* Codes 286 and 287 do not exist, but we must include them in the
225 : : * tree construction to get a canonical Huffman tree (longest code
226 : : * all ones)
227 : : */
228 : 0 : gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count);
229 : :
230 : : /* The static distance tree is trivial: */
231 [ # # ]: 0 : for (n = 0; n < D_CODES; n++) {
232 : 0 : static_dtree[n].Len = 5;
233 [ # # ]: 0 : static_dtree[n].Code = bitrev32((u32)n) >> (32 - 5);
234 : : }
235 : 0 : static_init_done = 1;
236 : : }
237 : :
238 : : /* ===========================================================================
239 : : * Initialize the tree data structures for a new zlib stream.
240 : : */
241 : 0 : void zlib_tr_init(
242 : : deflate_state *s
243 : : )
244 : : {
245 : 0 : tr_static_init();
246 : :
247 : 0 : s->compressed_len = 0L;
248 : :
249 : 0 : s->l_desc.dyn_tree = s->dyn_ltree;
250 : 0 : s->l_desc.stat_desc = &static_l_desc;
251 : :
252 : 0 : s->d_desc.dyn_tree = s->dyn_dtree;
253 : 0 : s->d_desc.stat_desc = &static_d_desc;
254 : :
255 : 0 : s->bl_desc.dyn_tree = s->bl_tree;
256 : 0 : s->bl_desc.stat_desc = &static_bl_desc;
257 : :
258 : 0 : s->bi_buf = 0;
259 : 0 : s->bi_valid = 0;
260 : 0 : s->last_eob_len = 8; /* enough lookahead for inflate */
261 : : #ifdef DEBUG_ZLIB
262 : : s->bits_sent = 0L;
263 : : #endif
264 : :
265 : : /* Initialize the first block of the first file: */
266 : 0 : init_block(s);
267 : 0 : }
268 : :
269 : : /* ===========================================================================
270 : : * Initialize a new block.
271 : : */
272 : 0 : static void init_block(
273 : : deflate_state *s
274 : : )
275 : : {
276 : 0 : int n; /* iterates over tree elements */
277 : :
278 : : /* Initialize the trees. */
279 [ # # # # ]: 0 : for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0;
280 [ # # # # ]: 0 : for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0;
281 [ # # # # ]: 0 : for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0;
282 : :
283 : 0 : s->dyn_ltree[END_BLOCK].Freq = 1;
284 : 0 : s->opt_len = s->static_len = 0L;
285 : 0 : s->last_lit = s->matches = 0;
286 : : }
287 : :
288 : : #define SMALLEST 1
289 : : /* Index within the heap array of least frequent node in the Huffman tree */
290 : :
291 : :
292 : : /* ===========================================================================
293 : : * Remove the smallest element from the heap and recreate the heap with
294 : : * one less element. Updates heap and heap_len.
295 : : */
296 : : #define pqremove(s, tree, top) \
297 : : {\
298 : : top = s->heap[SMALLEST]; \
299 : : s->heap[SMALLEST] = s->heap[s->heap_len--]; \
300 : : pqdownheap(s, tree, SMALLEST); \
301 : : }
302 : :
303 : : /* ===========================================================================
304 : : * Compares to subtrees, using the tree depth as tie breaker when
305 : : * the subtrees have equal frequency. This minimizes the worst case length.
306 : : */
307 : : #define smaller(tree, n, m, depth) \
308 : : (tree[n].Freq < tree[m].Freq || \
309 : : (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m]))
310 : :
311 : : /* ===========================================================================
312 : : * Restore the heap property by moving down the tree starting at node k,
313 : : * exchanging a node with the smallest of its two sons if necessary, stopping
314 : : * when the heap property is re-established (each father smaller than its
315 : : * two sons).
316 : : */
317 : 0 : static void pqdownheap(
318 : : deflate_state *s,
319 : : ct_data *tree, /* the tree to restore */
320 : : int k /* node to move down */
321 : : )
322 : : {
323 : 0 : int v = s->heap[k];
324 : 0 : int j = k << 1; /* left son of k */
325 [ # # ]: 0 : while (j <= s->heap_len) {
326 : : /* Set j to the smallest of the two sons: */
327 [ # # ]: 0 : if (j < s->heap_len &&
328 [ # # # # : 0 : smaller(tree, s->heap[j+1], s->heap[j], s->depth)) {
# # ]
329 : 0 : j++;
330 : : }
331 : : /* Exit if v is smaller than both sons */
332 [ # # # # : 0 : if (smaller(tree, v, s->heap[j], s->depth)) break;
# # ]
333 : :
334 : : /* Exchange v with the smallest son */
335 : 0 : s->heap[k] = s->heap[j]; k = j;
336 : :
337 : : /* And continue down the tree, setting j to the left son of k */
338 : 0 : j <<= 1;
339 : : }
340 : 0 : s->heap[k] = v;
341 : 0 : }
342 : :
343 : : /* ===========================================================================
344 : : * Compute the optimal bit lengths for a tree and update the total bit length
345 : : * for the current block.
346 : : * IN assertion: the fields freq and dad are set, heap[heap_max] and
347 : : * above are the tree nodes sorted by increasing frequency.
348 : : * OUT assertions: the field len is set to the optimal bit length, the
349 : : * array bl_count contains the frequencies for each bit length.
350 : : * The length opt_len is updated; static_len is also updated if stree is
351 : : * not null.
352 : : */
353 : 0 : static void gen_bitlen(
354 : : deflate_state *s,
355 : : tree_desc *desc /* the tree descriptor */
356 : : )
357 : : {
358 : 0 : ct_data *tree = desc->dyn_tree;
359 : 0 : int max_code = desc->max_code;
360 : 0 : const ct_data *stree = desc->stat_desc->static_tree;
361 : 0 : const int *extra = desc->stat_desc->extra_bits;
362 : 0 : int base = desc->stat_desc->extra_base;
363 : 0 : int max_length = desc->stat_desc->max_length;
364 : 0 : int h; /* heap index */
365 : 0 : int n, m; /* iterate over the tree elements */
366 : 0 : int bits; /* bit length */
367 : 0 : int xbits; /* extra bits */
368 : 0 : ush f; /* frequency */
369 : 0 : int overflow = 0; /* number of elements with bit length too large */
370 : :
371 [ # # ]: 0 : for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0;
372 : :
373 : : /* In a first pass, compute the optimal bit lengths (which may
374 : : * overflow in the case of the bit length tree).
375 : : */
376 : 0 : tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */
377 : :
378 [ # # ]: 0 : for (h = s->heap_max+1; h < HEAP_SIZE; h++) {
379 : 0 : n = s->heap[h];
380 : 0 : bits = tree[tree[n].Dad].Len + 1;
381 [ # # ]: 0 : if (bits > max_length) bits = max_length, overflow++;
382 : 0 : tree[n].Len = (ush)bits;
383 : : /* We overwrite tree[n].Dad which is no longer needed */
384 : :
385 [ # # ]: 0 : if (n > max_code) continue; /* not a leaf node */
386 : :
387 : 0 : s->bl_count[bits]++;
388 : 0 : xbits = 0;
389 [ # # ]: 0 : if (n >= base) xbits = extra[n-base];
390 : 0 : f = tree[n].Freq;
391 : 0 : s->opt_len += (ulg)f * (bits + xbits);
392 [ # # ]: 0 : if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits);
393 : : }
394 [ # # ]: 0 : if (overflow == 0) return;
395 : :
396 : 0 : Trace((stderr,"\nbit length overflow\n"));
397 : : /* This happens for example on obj2 and pic of the Calgary corpus */
398 : :
399 : : /* Find the first bit length which could increase: */
400 : 0 : do {
401 : 0 : bits = max_length-1;
402 [ # # ]: 0 : while (s->bl_count[bits] == 0) bits--;
403 : 0 : s->bl_count[bits]--; /* move one leaf down the tree */
404 : 0 : s->bl_count[bits+1] += 2; /* move one overflow item as its brother */
405 : 0 : s->bl_count[max_length]--;
406 : : /* The brother of the overflow item also moves one step up,
407 : : * but this does not affect bl_count[max_length]
408 : : */
409 : 0 : overflow -= 2;
410 [ # # ]: 0 : } while (overflow > 0);
411 : :
412 : : /* Now recompute all bit lengths, scanning in increasing frequency.
413 : : * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all
414 : : * lengths instead of fixing only the wrong ones. This idea is taken
415 : : * from 'ar' written by Haruhiko Okumura.)
416 : : */
417 [ # # ]: 0 : for (bits = max_length; bits != 0; bits--) {
418 : 0 : n = s->bl_count[bits];
419 [ # # ]: 0 : while (n != 0) {
420 : 0 : m = s->heap[--h];
421 [ # # ]: 0 : if (m > max_code) continue;
422 [ # # ]: 0 : if (tree[m].Len != (unsigned) bits) {
423 : 0 : Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits));
424 : 0 : s->opt_len += ((long)bits - (long)tree[m].Len)
425 : 0 : *(long)tree[m].Freq;
426 : 0 : tree[m].Len = (ush)bits;
427 : : }
428 : 0 : n--;
429 : : }
430 : : }
431 : : }
432 : :
433 : : /* ===========================================================================
434 : : * Generate the codes for a given tree and bit counts (which need not be
435 : : * optimal).
436 : : * IN assertion: the array bl_count contains the bit length statistics for
437 : : * the given tree and the field len is set for all tree elements.
438 : : * OUT assertion: the field code is set for all tree elements of non
439 : : * zero code length.
440 : : */
441 : 0 : static void gen_codes(
442 : : ct_data *tree, /* the tree to decorate */
443 : : int max_code, /* largest code with non zero frequency */
444 : : ush *bl_count /* number of codes at each bit length */
445 : : )
446 : : {
447 : 0 : ush next_code[MAX_BITS+1]; /* next code value for each bit length */
448 : 0 : ush code = 0; /* running code value */
449 : 0 : int bits; /* bit index */
450 : 0 : int n; /* code index */
451 : :
452 : : /* The distribution counts are first used to generate the code values
453 : : * without bit reversal.
454 : : */
455 [ # # ]: 0 : for (bits = 1; bits <= MAX_BITS; bits++) {
456 : 0 : next_code[bits] = code = (code + bl_count[bits-1]) << 1;
457 : : }
458 : : /* Check that the bit counts in bl_count are consistent. The last code
459 : : * must be all ones.
460 : : */
461 : : Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1,
462 : : "inconsistent bit counts");
463 : : Tracev((stderr,"\ngen_codes: max_code %d ", max_code));
464 : :
465 [ # # ]: 0 : for (n = 0; n <= max_code; n++) {
466 : 0 : int len = tree[n].Len;
467 [ # # ]: 0 : if (len == 0) continue;
468 : : /* Now reverse the bits */
469 [ # # ]: 0 : tree[n].Code = bitrev32((u32)(next_code[len]++)) >> (32 - len);
470 : :
471 : : Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ",
472 : 0 : n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1));
473 : : }
474 : 0 : }
475 : :
476 : : /* ===========================================================================
477 : : * Construct one Huffman tree and assigns the code bit strings and lengths.
478 : : * Update the total bit length for the current block.
479 : : * IN assertion: the field freq is set for all tree elements.
480 : : * OUT assertions: the fields len and code are set to the optimal bit length
481 : : * and corresponding code. The length opt_len is updated; static_len is
482 : : * also updated if stree is not null. The field max_code is set.
483 : : */
484 : 0 : static void build_tree(
485 : : deflate_state *s,
486 : : tree_desc *desc /* the tree descriptor */
487 : : )
488 : : {
489 : 0 : ct_data *tree = desc->dyn_tree;
490 : 0 : const ct_data *stree = desc->stat_desc->static_tree;
491 : 0 : int elems = desc->stat_desc->elems;
492 : 0 : int n, m; /* iterate over heap elements */
493 : 0 : int max_code = -1; /* largest code with non zero frequency */
494 : 0 : int node; /* new node being created */
495 : :
496 : : /* Construct the initial heap, with least frequent element in
497 : : * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1].
498 : : * heap[0] is not used.
499 : : */
500 : 0 : s->heap_len = 0, s->heap_max = HEAP_SIZE;
501 : :
502 [ # # ]: 0 : for (n = 0; n < elems; n++) {
503 [ # # ]: 0 : if (tree[n].Freq != 0) {
504 : 0 : s->heap[++(s->heap_len)] = max_code = n;
505 : 0 : s->depth[n] = 0;
506 : : } else {
507 : 0 : tree[n].Len = 0;
508 : : }
509 : : }
510 : :
511 : : /* The pkzip format requires that at least one distance code exists,
512 : : * and that at least one bit should be sent even if there is only one
513 : : * possible code. So to avoid special checks later on we force at least
514 : : * two codes of non zero frequency.
515 : : */
516 [ # # ]: 0 : while (s->heap_len < 2) {
517 [ # # ]: 0 : node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0);
518 : 0 : tree[node].Freq = 1;
519 : 0 : s->depth[node] = 0;
520 [ # # ]: 0 : s->opt_len--; if (stree) s->static_len -= stree[node].Len;
521 : : /* node is 0 or 1 so it does not have extra bits */
522 : : }
523 : 0 : desc->max_code = max_code;
524 : :
525 : : /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree,
526 : : * establish sub-heaps of increasing lengths:
527 : : */
528 [ # # ]: 0 : for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, n);
529 : :
530 : : /* Construct the Huffman tree by repeatedly combining the least two
531 : : * frequent nodes.
532 : : */
533 : : node = elems; /* next internal node of the tree */
534 : 0 : do {
535 : 0 : pqremove(s, tree, n); /* n = node of least frequency */
536 : 0 : m = s->heap[SMALLEST]; /* m = node of next least frequency */
537 : :
538 : 0 : s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */
539 : 0 : s->heap[--(s->heap_max)] = m;
540 : :
541 : : /* Create a new node father of n and m */
542 : 0 : tree[node].Freq = tree[n].Freq + tree[m].Freq;
543 : 0 : s->depth[node] = (uch) (max(s->depth[n], s->depth[m]) + 1);
544 : 0 : tree[n].Dad = tree[m].Dad = (ush)node;
545 : : #ifdef DUMP_BL_TREE
546 : : if (tree == s->bl_tree) {
547 : : fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)",
548 : : node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq);
549 : : }
550 : : #endif
551 : : /* and insert the new node in the heap */
552 : 0 : s->heap[SMALLEST] = node++;
553 : 0 : pqdownheap(s, tree, SMALLEST);
554 : :
555 [ # # ]: 0 : } while (s->heap_len >= 2);
556 : :
557 : 0 : s->heap[--(s->heap_max)] = s->heap[SMALLEST];
558 : :
559 : : /* At this point, the fields freq and dad are set. We can now
560 : : * generate the bit lengths.
561 : : */
562 : 0 : gen_bitlen(s, (tree_desc *)desc);
563 : :
564 : : /* The field len is now set, we can generate the bit codes */
565 : 0 : gen_codes ((ct_data *)tree, max_code, s->bl_count);
566 : 0 : }
567 : :
568 : : /* ===========================================================================
569 : : * Scan a literal or distance tree to determine the frequencies of the codes
570 : : * in the bit length tree.
571 : : */
572 : 0 : static void scan_tree(
573 : : deflate_state *s,
574 : : ct_data *tree, /* the tree to be scanned */
575 : : int max_code /* and its largest code of non zero frequency */
576 : : )
577 : : {
578 : 0 : int n; /* iterates over all tree elements */
579 : 0 : int prevlen = -1; /* last emitted length */
580 : 0 : int curlen; /* length of current code */
581 : 0 : int nextlen = tree[0].Len; /* length of next code */
582 : 0 : int count = 0; /* repeat count of the current code */
583 : 0 : int max_count = 7; /* max repeat count */
584 : 0 : int min_count = 4; /* min repeat count */
585 : :
586 [ # # ]: 0 : if (nextlen == 0) max_count = 138, min_count = 3;
587 : 0 : tree[max_code+1].Len = (ush)0xffff; /* guard */
588 : :
589 [ # # ]: 0 : for (n = 0; n <= max_code; n++) {
590 : 0 : curlen = nextlen; nextlen = tree[n+1].Len;
591 [ # # # # ]: 0 : if (++count < max_count && curlen == nextlen) {
592 : 0 : continue;
593 [ # # ]: 0 : } else if (count < min_count) {
594 : 0 : s->bl_tree[curlen].Freq += count;
595 [ # # ]: 0 : } else if (curlen != 0) {
596 [ # # ]: 0 : if (curlen != prevlen) s->bl_tree[curlen].Freq++;
597 : 0 : s->bl_tree[REP_3_6].Freq++;
598 [ # # ]: 0 : } else if (count <= 10) {
599 : 0 : s->bl_tree[REPZ_3_10].Freq++;
600 : : } else {
601 : 0 : s->bl_tree[REPZ_11_138].Freq++;
602 : : }
603 : 0 : count = 0; prevlen = curlen;
604 [ # # ]: 0 : if (nextlen == 0) {
605 : : max_count = 138, min_count = 3;
606 [ # # ]: 0 : } else if (curlen == nextlen) {
607 : : max_count = 6, min_count = 3;
608 : : } else {
609 : 0 : max_count = 7, min_count = 4;
610 : : }
611 : : }
612 : 0 : }
613 : :
614 : : /* ===========================================================================
615 : : * Send a literal or distance tree in compressed form, using the codes in
616 : : * bl_tree.
617 : : */
618 : 0 : static void send_tree(
619 : : deflate_state *s,
620 : : ct_data *tree, /* the tree to be scanned */
621 : : int max_code /* and its largest code of non zero frequency */
622 : : )
623 : : {
624 : 0 : int n; /* iterates over all tree elements */
625 : 0 : int prevlen = -1; /* last emitted length */
626 : 0 : int curlen; /* length of current code */
627 : 0 : int nextlen = tree[0].Len; /* length of next code */
628 : 0 : int count = 0; /* repeat count of the current code */
629 : 0 : int max_count = 7; /* max repeat count */
630 : 0 : int min_count = 4; /* min repeat count */
631 : :
632 : : /* tree[max_code+1].Len = -1; */ /* guard already set */
633 [ # # ]: 0 : if (nextlen == 0) max_count = 138, min_count = 3;
634 : :
635 [ # # ]: 0 : for (n = 0; n <= max_code; n++) {
636 : 0 : curlen = nextlen; nextlen = tree[n+1].Len;
637 [ # # # # ]: 0 : if (++count < max_count && curlen == nextlen) {
638 : 0 : continue;
639 [ # # ]: 0 : } else if (count < min_count) {
640 [ # # # # ]: 0 : do { send_code(s, curlen, s->bl_tree); } while (--count != 0);
641 : :
642 [ # # ]: 0 : } else if (curlen != 0) {
643 [ # # ]: 0 : if (curlen != prevlen) {
644 [ # # ]: 0 : send_code(s, curlen, s->bl_tree); count--;
645 : : }
646 : 0 : Assert(count >= 3 && count <= 6, " 3_6?");
647 [ # # # # ]: 0 : send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2);
648 : :
649 [ # # ]: 0 : } else if (count <= 10) {
650 [ # # # # ]: 0 : send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3);
651 : :
652 : : } else {
653 [ # # # # ]: 0 : send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7);
654 : : }
655 : 0 : count = 0; prevlen = curlen;
656 [ # # ]: 0 : if (nextlen == 0) {
657 : : max_count = 138, min_count = 3;
658 [ # # ]: 0 : } else if (curlen == nextlen) {
659 : : max_count = 6, min_count = 3;
660 : : } else {
661 : 0 : max_count = 7, min_count = 4;
662 : : }
663 : : }
664 : 0 : }
665 : :
666 : : /* ===========================================================================
667 : : * Construct the Huffman tree for the bit lengths and return the index in
668 : : * bl_order of the last bit length code to send.
669 : : */
670 : 0 : static int build_bl_tree(
671 : : deflate_state *s
672 : : )
673 : : {
674 : 0 : int max_blindex; /* index of last bit length code of non zero freq */
675 : :
676 : : /* Determine the bit length frequencies for literal and distance trees */
677 : 0 : scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code);
678 : 0 : scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code);
679 : :
680 : : /* Build the bit length tree: */
681 : 0 : build_tree(s, (tree_desc *)(&(s->bl_desc)));
682 : : /* opt_len now includes the length of the tree representations, except
683 : : * the lengths of the bit lengths codes and the 5+5+4 bits for the counts.
684 : : */
685 : :
686 : : /* Determine the number of bit length codes to send. The pkzip format
687 : : * requires that at least 4 bit length codes be sent. (appnote.txt says
688 : : * 3 but the actual value used is 4.)
689 : : */
690 [ # # ]: 0 : for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) {
691 [ # # ]: 0 : if (s->bl_tree[bl_order[max_blindex]].Len != 0) break;
692 : : }
693 : : /* Update opt_len to include the bit length tree and counts */
694 : 0 : s->opt_len += 3*(max_blindex+1) + 5+5+4;
695 : : Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld",
696 : 0 : s->opt_len, s->static_len));
697 : :
698 : 0 : return max_blindex;
699 : : }
700 : :
701 : : /* ===========================================================================
702 : : * Send the header for a block using dynamic Huffman trees: the counts, the
703 : : * lengths of the bit length codes, the literal tree and the distance tree.
704 : : * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.
705 : : */
706 : 0 : static void send_all_trees(
707 : : deflate_state *s,
708 : : int lcodes, /* number of codes for each tree */
709 : : int dcodes, /* number of codes for each tree */
710 : : int blcodes /* number of codes for each tree */
711 : : )
712 : : {
713 : 0 : int rank; /* index in bl_order */
714 : :
715 : 0 : Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes");
716 : : Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES,
717 : 0 : "too many codes");
718 : 0 : Tracev((stderr, "\nbl counts: "));
719 [ # # ]: 0 : send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */
720 [ # # ]: 0 : send_bits(s, dcodes-1, 5);
721 [ # # ]: 0 : send_bits(s, blcodes-4, 4); /* not -3 as stated in appnote.txt */
722 [ # # ]: 0 : for (rank = 0; rank < blcodes; rank++) {
723 : 0 : Tracev((stderr, "\nbl code %2d ", bl_order[rank]));
724 [ # # ]: 0 : send_bits(s, s->bl_tree[bl_order[rank]].Len, 3);
725 : : }
726 : 0 : Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent));
727 : :
728 : 0 : send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */
729 : 0 : Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent));
730 : :
731 : 0 : send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */
732 : 0 : Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent));
733 : 0 : }
734 : :
735 : : /* ===========================================================================
736 : : * Send a stored block
737 : : */
738 : 0 : void zlib_tr_stored_block(
739 : : deflate_state *s,
740 : : char *buf, /* input block */
741 : : ulg stored_len, /* length of input block */
742 : : int eof /* true if this is the last block for a file */
743 : : )
744 : : {
745 [ # # ]: 0 : send_bits(s, (STORED_BLOCK<<1)+eof, 3); /* send block type */
746 : 0 : s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L;
747 : 0 : s->compressed_len += (stored_len + 4) << 3;
748 : :
749 : 0 : copy_block(s, buf, (unsigned)stored_len, 1); /* with header */
750 : 0 : }
751 : :
752 : : /* Send just the `stored block' type code without any length bytes or data.
753 : : */
754 : 0 : void zlib_tr_stored_type_only(
755 : : deflate_state *s
756 : : )
757 : : {
758 [ # # ]: 0 : send_bits(s, (STORED_BLOCK << 1), 3);
759 : 0 : bi_windup(s);
760 : 0 : s->compressed_len = (s->compressed_len + 3) & ~7L;
761 : 0 : }
762 : :
763 : :
764 : : /* ===========================================================================
765 : : * Send one empty static block to give enough lookahead for inflate.
766 : : * This takes 10 bits, of which 7 may remain in the bit buffer.
767 : : * The current inflate code requires 9 bits of lookahead. If the
768 : : * last two codes for the previous block (real code plus EOB) were coded
769 : : * on 5 bits or less, inflate may have only 5+3 bits of lookahead to decode
770 : : * the last real code. In this case we send two empty static blocks instead
771 : : * of one. (There are no problems if the previous block is stored or fixed.)
772 : : * To simplify the code, we assume the worst case of last real code encoded
773 : : * on one bit only.
774 : : */
775 : 0 : void zlib_tr_align(
776 : : deflate_state *s
777 : : )
778 : : {
779 [ # # ]: 0 : send_bits(s, STATIC_TREES<<1, 3);
780 [ # # ]: 0 : send_code(s, END_BLOCK, static_ltree);
781 : 0 : s->compressed_len += 10L; /* 3 for block type, 7 for EOB */
782 : 0 : bi_flush(s);
783 : : /* Of the 10 bits for the empty block, we have already sent
784 : : * (10 - bi_valid) bits. The lookahead for the last real code (before
785 : : * the EOB of the previous block) was thus at least one plus the length
786 : : * of the EOB plus what we have just sent of the empty static block.
787 : : */
788 [ # # ]: 0 : if (1 + s->last_eob_len + 10 - s->bi_valid < 9) {
789 [ # # ]: 0 : send_bits(s, STATIC_TREES<<1, 3);
790 [ # # ]: 0 : send_code(s, END_BLOCK, static_ltree);
791 : 0 : s->compressed_len += 10L;
792 : 0 : bi_flush(s);
793 : : }
794 : 0 : s->last_eob_len = 7;
795 : 0 : }
796 : :
797 : : /* ===========================================================================
798 : : * Determine the best encoding for the current block: dynamic trees, static
799 : : * trees or store, and output the encoded block to the zip file. This function
800 : : * returns the total compressed length for the file so far.
801 : : */
802 : 0 : ulg zlib_tr_flush_block(
803 : : deflate_state *s,
804 : : char *buf, /* input block, or NULL if too old */
805 : : ulg stored_len, /* length of input block */
806 : : int eof /* true if this is the last block for a file */
807 : : )
808 : : {
809 : 0 : ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */
810 : 0 : int max_blindex = 0; /* index of last bit length code of non zero freq */
811 : :
812 : : /* Build the Huffman trees unless a stored block is forced */
813 [ # # ]: 0 : if (s->level > 0) {
814 : :
815 : : /* Check if the file is ascii or binary */
816 [ # # ]: 0 : if (s->data_type == Z_UNKNOWN) set_data_type(s);
817 : :
818 : : /* Construct the literal and distance trees */
819 : 0 : build_tree(s, (tree_desc *)(&(s->l_desc)));
820 : : Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len,
821 : 0 : s->static_len));
822 : :
823 : 0 : build_tree(s, (tree_desc *)(&(s->d_desc)));
824 : : Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len,
825 : 0 : s->static_len));
826 : : /* At this point, opt_len and static_len are the total bit lengths of
827 : : * the compressed block data, excluding the tree representations.
828 : : */
829 : :
830 : : /* Build the bit length tree for the above two trees, and get the index
831 : : * in bl_order of the last bit length code to send.
832 : : */
833 : 0 : max_blindex = build_bl_tree(s);
834 : :
835 : : /* Determine the best encoding. Compute first the block length in bytes*/
836 : 0 : opt_lenb = (s->opt_len+3+7)>>3;
837 : 0 : static_lenb = (s->static_len+3+7)>>3;
838 : :
839 : : Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ",
840 : : opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len,
841 : 0 : s->last_lit));
842 : :
843 : 0 : if (static_lenb <= opt_lenb) opt_lenb = static_lenb;
844 : :
845 : : } else {
846 : 0 : Assert(buf != (char*)0, "lost buf");
847 : 0 : opt_lenb = static_lenb = stored_len + 5; /* force a stored block */
848 : : }
849 : :
850 : : /* If compression failed and this is the first and last block,
851 : : * and if the .zip file can be seeked (to rewrite the local header),
852 : : * the whole file is transformed into a stored file:
853 : : */
854 : : #ifdef STORED_FILE_OK
855 : : # ifdef FORCE_STORED_FILE
856 : : if (eof && s->compressed_len == 0L) { /* force stored file */
857 : : # else
858 : : if (stored_len <= opt_lenb && eof && s->compressed_len==0L && seekable()) {
859 : : # endif
860 : : /* Since LIT_BUFSIZE <= 2*WSIZE, the input data must be there: */
861 : : if (buf == (char*)0) error ("block vanished");
862 : :
863 : : copy_block(s, buf, (unsigned)stored_len, 0); /* without header */
864 : : s->compressed_len = stored_len << 3;
865 : : s->method = STORED;
866 : : } else
867 : : #endif /* STORED_FILE_OK */
868 : :
869 : : #ifdef FORCE_STORED
870 : : if (buf != (char*)0) { /* force stored block */
871 : : #else
872 [ # # # # ]: 0 : if (stored_len+4 <= opt_lenb && buf != (char*)0) {
873 : : /* 4: two words for the lengths */
874 : : #endif
875 : : /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.
876 : : * Otherwise we can't have processed more than WSIZE input bytes since
877 : : * the last block flush, because compression would have been
878 : : * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to
879 : : * transform a block into a stored block.
880 : : */
881 : 0 : zlib_tr_stored_block(s, buf, stored_len, eof);
882 : :
883 : : #ifdef FORCE_STATIC
884 : : } else if (static_lenb >= 0) { /* force static trees */
885 : : #else
886 [ # # ]: 0 : } else if (static_lenb == opt_lenb) {
887 : : #endif
888 [ # # ]: 0 : send_bits(s, (STATIC_TREES<<1)+eof, 3);
889 : 0 : compress_block(s, (ct_data *)static_ltree, (ct_data *)static_dtree);
890 : 0 : s->compressed_len += 3 + s->static_len;
891 : : } else {
892 [ # # ]: 0 : send_bits(s, (DYN_TREES<<1)+eof, 3);
893 : 0 : send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1,
894 : : max_blindex+1);
895 : 0 : compress_block(s, (ct_data *)s->dyn_ltree, (ct_data *)s->dyn_dtree);
896 : 0 : s->compressed_len += 3 + s->opt_len;
897 : : }
898 : : Assert (s->compressed_len == s->bits_sent, "bad compressed size");
899 : : init_block(s);
900 : :
901 [ # # ]: 0 : if (eof) {
902 : 0 : bi_windup(s);
903 : 0 : s->compressed_len += 7; /* align on byte boundary */
904 : : }
905 : : Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3,
906 : 0 : s->compressed_len-7*eof));
907 : :
908 : 0 : return s->compressed_len >> 3;
909 : : }
910 : :
911 : : /* ===========================================================================
912 : : * Save the match info and tally the frequency counts. Return true if
913 : : * the current block must be flushed.
914 : : */
915 : 0 : int zlib_tr_tally(
916 : : deflate_state *s,
917 : : unsigned dist, /* distance of matched string */
918 : : unsigned lc /* match length-MIN_MATCH or unmatched char (if dist==0) */
919 : : )
920 : : {
921 : 0 : s->d_buf[s->last_lit] = (ush)dist;
922 : 0 : s->l_buf[s->last_lit++] = (uch)lc;
923 [ # # ]: 0 : if (dist == 0) {
924 : : /* lc is the unmatched char */
925 : 0 : s->dyn_ltree[lc].Freq++;
926 : : } else {
927 : 0 : s->matches++;
928 : : /* Here, lc is the match length - MIN_MATCH */
929 : 0 : dist--; /* dist = match distance - 1 */
930 : : Assert((ush)dist < (ush)MAX_DIST(s) &&
931 : : (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) &&
932 : 0 : (ush)d_code(dist) < (ush)D_CODES, "zlib_tr_tally: bad match");
933 : :
934 : 0 : s->dyn_ltree[length_code[lc]+LITERALS+1].Freq++;
935 [ # # ]: 0 : s->dyn_dtree[d_code(dist)].Freq++;
936 : : }
937 : :
938 : : /* Try to guess if it is profitable to stop the current block here */
939 [ # # # # ]: 0 : if ((s->last_lit & 0xfff) == 0 && s->level > 2) {
940 : : /* Compute an upper bound for the compressed length */
941 : 0 : ulg out_length = (ulg)s->last_lit*8L;
942 : 0 : ulg in_length = (ulg)((long)s->strstart - s->block_start);
943 : 0 : int dcode;
944 [ # # ]: 0 : for (dcode = 0; dcode < D_CODES; dcode++) {
945 : 0 : out_length += (ulg)s->dyn_dtree[dcode].Freq *
946 : 0 : (5L+extra_dbits[dcode]);
947 : : }
948 : 0 : out_length >>= 3;
949 : : Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ",
950 : : s->last_lit, in_length, out_length,
951 : 0 : 100L - out_length*100L/in_length));
952 [ # # # # ]: 0 : if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1;
953 : : }
954 : 0 : return (s->last_lit == s->lit_bufsize-1);
955 : : /* We avoid equality with lit_bufsize because of wraparound at 64K
956 : : * on 16 bit machines and because stored blocks are restricted to
957 : : * 64K-1 bytes.
958 : : */
959 : : }
960 : :
961 : : /* ===========================================================================
962 : : * Send the block data compressed using the given Huffman trees
963 : : */
964 : 0 : static void compress_block(
965 : : deflate_state *s,
966 : : ct_data *ltree, /* literal tree */
967 : : ct_data *dtree /* distance tree */
968 : : )
969 : : {
970 : 0 : unsigned dist; /* distance of matched string */
971 : 0 : int lc; /* match length or unmatched char (if dist == 0) */
972 : 0 : unsigned lx = 0; /* running index in l_buf */
973 : 0 : unsigned code; /* the code to send */
974 : 0 : int extra; /* number of extra bits to send */
975 : :
976 [ # # ]: 0 : if (s->last_lit != 0) do {
977 : 0 : dist = s->d_buf[lx];
978 : 0 : lc = s->l_buf[lx++];
979 [ # # ]: 0 : if (dist == 0) {
980 [ # # ]: 0 : send_code(s, lc, ltree); /* send a literal byte */
981 : : Tracecv(isgraph(lc), (stderr," '%c' ", lc));
982 : : } else {
983 : : /* Here, lc is the match length - MIN_MATCH */
984 : 0 : code = length_code[lc];
985 [ # # ]: 0 : send_code(s, code+LITERALS+1, ltree); /* send the length code */
986 : 0 : extra = extra_lbits[code];
987 [ # # ]: 0 : if (extra != 0) {
988 : 0 : lc -= base_length[code];
989 [ # # ]: 0 : send_bits(s, lc, extra); /* send the extra length bits */
990 : : }
991 : 0 : dist--; /* dist is now the match distance - 1 */
992 [ # # ]: 0 : code = d_code(dist);
993 : 0 : Assert (code < D_CODES, "bad d_code");
994 : :
995 [ # # ]: 0 : send_code(s, code, dtree); /* send the distance code */
996 : 0 : extra = extra_dbits[code];
997 [ # # ]: 0 : if (extra != 0) {
998 : 0 : dist -= base_dist[code];
999 [ # # ]: 0 : send_bits(s, dist, extra); /* send the extra distance bits */
1000 : : }
1001 : : } /* literal or match pair ? */
1002 : :
1003 : : /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */
1004 : 0 : Assert(s->pending < s->lit_bufsize + 2*lx, "pendingBuf overflow");
1005 : :
1006 [ # # ]: 0 : } while (lx < s->last_lit);
1007 : :
1008 [ # # ]: 0 : send_code(s, END_BLOCK, ltree);
1009 : 0 : s->last_eob_len = ltree[END_BLOCK].Len;
1010 : 0 : }
1011 : :
1012 : : /* ===========================================================================
1013 : : * Set the data type to ASCII or BINARY, using a crude approximation:
1014 : : * binary if more than 20% of the bytes are <= 6 or >= 128, ascii otherwise.
1015 : : * IN assertion: the fields freq of dyn_ltree are set and the total of all
1016 : : * frequencies does not exceed 64K (to fit in an int on 16 bit machines).
1017 : : */
1018 : : static void set_data_type(
1019 : : deflate_state *s
1020 : : )
1021 : : {
1022 : : int n = 0;
1023 : : unsigned ascii_freq = 0;
1024 : : unsigned bin_freq = 0;
1025 [ # # ]: 0 : while (n < 7) bin_freq += s->dyn_ltree[n++].Freq;
1026 [ # # ]: 0 : while (n < 128) ascii_freq += s->dyn_ltree[n++].Freq;
1027 [ # # ]: 0 : while (n < LITERALS) bin_freq += s->dyn_ltree[n++].Freq;
1028 : 0 : s->data_type = (Byte)(bin_freq > (ascii_freq >> 2) ? Z_BINARY : Z_ASCII);
1029 : 0 : }
1030 : :
1031 : : /* ===========================================================================
1032 : : * Copy a stored block, storing first the length and its
1033 : : * one's complement if requested.
1034 : : */
1035 : 0 : static void copy_block(
1036 : : deflate_state *s,
1037 : : char *buf, /* the input data */
1038 : : unsigned len, /* its length */
1039 : : int header /* true if block header must be written */
1040 : : )
1041 : : {
1042 : 0 : bi_windup(s); /* align on byte boundary */
1043 : 0 : s->last_eob_len = 8; /* enough lookahead for inflate */
1044 : :
1045 [ # # ]: 0 : if (header) {
1046 : 0 : put_short(s, (ush)len);
1047 : 0 : put_short(s, (ush)~len);
1048 : : #ifdef DEBUG_ZLIB
1049 : : s->bits_sent += 2*16;
1050 : : #endif
1051 : : }
1052 : : #ifdef DEBUG_ZLIB
1053 : : s->bits_sent += (ulg)len<<3;
1054 : : #endif
1055 : : /* bundle up the put_byte(s, *buf++) calls */
1056 : 0 : memcpy(&s->pending_buf[s->pending], buf, len);
1057 : 0 : s->pending += len;
1058 : 0 : }
1059 : :
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