1 | /* |
2 | * Copyright (c) 2008-2016 Apple Inc. All rights reserved. |
3 | * |
4 | * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ |
5 | * |
6 | * This file contains Original Code and/or Modifications of Original Code |
7 | * as defined in and that are subject to the Apple Public Source License |
8 | * Version 2.0 (the 'License'). You may not use this file except in |
9 | * compliance with the License. The rights granted to you under the License |
10 | * may not be used to create, or enable the creation or redistribution of, |
11 | * unlawful or unlicensed copies of an Apple operating system, or to |
12 | * circumvent, violate, or enable the circumvention or violation of, any |
13 | * terms of an Apple operating system software license agreement. |
14 | * |
15 | * Please obtain a copy of the License at |
16 | * http://www.opensource.apple.com/apsl/ and read it before using this file. |
17 | * |
18 | * The Original Code and all software distributed under the License are |
19 | * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER |
20 | * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, |
21 | * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, |
22 | * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. |
23 | * Please see the License for the specific language governing rights and |
24 | * limitations under the License. |
25 | * |
26 | * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ |
27 | */ |
28 | /* trees.c -- output deflated data using Huffman coding |
29 | * Copyright (C) 1995-2005 Jean-loup Gailly |
30 | * For conditions of distribution and use, see copyright notice in zlib.h |
31 | */ |
32 | |
33 | /* |
34 | * ALGORITHM |
35 | * |
36 | * The "deflation" process uses several Huffman trees. The more |
37 | * common source values are represented by shorter bit sequences. |
38 | * |
39 | * Each code tree is stored in a compressed form which is itself |
40 | * a Huffman encoding of the lengths of all the code strings (in |
41 | * ascending order by source values). The actual code strings are |
42 | * reconstructed from the lengths in the inflate process, as described |
43 | * in the deflate specification. |
44 | * |
45 | * REFERENCES |
46 | * |
47 | * Deutsch, L.P.,"'Deflate' Compressed Data Format Specification". |
48 | * Available in ftp.uu.net:/pub/archiving/zip/doc/deflate-1.1.doc |
49 | * |
50 | * Storer, James A. |
51 | * Data Compression: Methods and Theory, pp. 49-50. |
52 | * Computer Science Press, 1988. ISBN 0-7167-8156-5. |
53 | * |
54 | * Sedgewick, R. |
55 | * Algorithms, p290. |
56 | * Addison-Wesley, 1983. ISBN 0-201-06672-6. |
57 | */ |
58 | |
59 | /* @(#) $Id$ */ |
60 | |
61 | /* #define GEN_TREES_H */ |
62 | |
63 | #include "deflate.h" |
64 | |
65 | #ifdef DEBUG |
66 | # include <ctype.h> |
67 | #endif |
68 | |
69 | /* =========================================================================== |
70 | * Constants |
71 | */ |
72 | |
73 | #define MAX_BL_BITS 7 |
74 | /* Bit length codes must not exceed MAX_BL_BITS bits */ |
75 | |
76 | #define END_BLOCK 256 |
77 | /* end of block literal code */ |
78 | |
79 | #define REP_3_6 16 |
80 | /* repeat previous bit length 3-6 times (2 bits of repeat count) */ |
81 | |
82 | #define REPZ_3_10 17 |
83 | /* repeat a zero length 3-10 times (3 bits of repeat count) */ |
84 | |
85 | #define REPZ_11_138 18 |
86 | /* repeat a zero length 11-138 times (7 bits of repeat count) */ |
87 | |
88 | local const int [LENGTH_CODES] /* extra bits for each length code */ |
89 | = {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}; |
90 | |
91 | local const int [D_CODES] /* extra bits for each distance code */ |
92 | = {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}; |
93 | |
94 | local const int [BL_CODES]/* extra bits for each bit length code */ |
95 | = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7}; |
96 | |
97 | local const uch bl_order[BL_CODES] |
98 | = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15}; |
99 | /* The lengths of the bit length codes are sent in order of decreasing |
100 | * probability, to avoid transmitting the lengths for unused bit length codes. |
101 | */ |
102 | |
103 | #define Buf_size (8 * 2*sizeof(char)) |
104 | /* Number of bits used within bi_buf. (bi_buf might be implemented on |
105 | * more than 16 bits on some systems.) |
106 | */ |
107 | |
108 | /* =========================================================================== |
109 | * Local data. These are initialized only once. |
110 | */ |
111 | |
112 | #define DIST_CODE_LEN 512 /* see definition of array dist_code below */ |
113 | |
114 | #if defined(GEN_TREES_H) || !defined(STDC) |
115 | /* non ANSI compilers may not accept trees.h */ |
116 | |
117 | local ct_data static_ltree[L_CODES+2]; |
118 | /* The static literal tree. Since the bit lengths are imposed, there is no |
119 | * need for the L_CODES extra codes used during heap construction. However |
120 | * The codes 286 and 287 are needed to build a canonical tree (see _tr_init |
121 | * below). |
122 | */ |
123 | |
124 | local ct_data static_dtree[D_CODES]; |
125 | /* The static distance tree. (Actually a trivial tree since all codes use |
126 | * 5 bits.) |
127 | */ |
128 | |
129 | uch _dist_code[DIST_CODE_LEN]; |
130 | /* Distance codes. The first 256 values correspond to the distances |
131 | * 3 .. 258, the last 256 values correspond to the top 8 bits of |
132 | * the 15 bit distances. |
133 | */ |
134 | |
135 | uch _length_code[MAX_MATCH-MIN_MATCH+1]; |
136 | /* length code for each normalized match length (0 == MIN_MATCH) */ |
137 | |
138 | local int base_length[LENGTH_CODES]; |
139 | /* First normalized length for each code (0 = MIN_MATCH) */ |
140 | |
141 | local int base_dist[D_CODES]; |
142 | /* First normalized distance for each code (0 = distance of 1) */ |
143 | |
144 | #else |
145 | # include "trees.h" |
146 | #endif /* GEN_TREES_H */ |
147 | |
148 | struct static_tree_desc_s { |
149 | const ct_data *static_tree; /* static tree or NULL */ |
150 | const intf *; /* extra bits for each code or NULL */ |
151 | int ; /* base index for extra_bits */ |
152 | int elems; /* max number of elements in the tree */ |
153 | int max_length; /* max bit length for the codes */ |
154 | }; |
155 | |
156 | local static_tree_desc static_l_desc = |
157 | {static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS}; |
158 | |
159 | local static_tree_desc static_d_desc = |
160 | {static_dtree, extra_dbits, 0, D_CODES, MAX_BITS}; |
161 | |
162 | local static_tree_desc static_bl_desc = |
163 | {(const ct_data *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS}; |
164 | |
165 | /* =========================================================================== |
166 | * Local (static) routines in this file. |
167 | */ |
168 | |
169 | local void tr_static_init OF((void)); |
170 | local void init_block OF((deflate_state *s)); |
171 | local void pqdownheap OF((deflate_state *s, ct_data *tree, int k)); |
172 | local void gen_bitlen OF((deflate_state *s, tree_desc *desc)); |
173 | local void gen_codes OF((ct_data *tree, int max_code, ushf *bl_count)); |
174 | local void build_tree OF((deflate_state *s, tree_desc *desc)); |
175 | local void scan_tree OF((deflate_state *s, ct_data *tree, int max_code)); |
176 | local void send_tree OF((deflate_state *s, ct_data *tree, int max_code)); |
177 | local int build_bl_tree OF((deflate_state *s)); |
178 | local void send_all_trees OF((deflate_state *s, int lcodes, int dcodes, |
179 | int blcodes)); |
180 | local void compress_block OF((deflate_state *s, ct_data *ltree, |
181 | ct_data *dtree)); |
182 | local void set_data_type OF((deflate_state *s)); |
183 | local unsigned bi_reverse OF((unsigned value, int length)); |
184 | local void bi_windup OF((deflate_state *s)); |
185 | local void bi_flush OF((deflate_state *s)); |
186 | local void copy_block OF((deflate_state *s, charf *buf, unsigned len, |
187 | int )); |
188 | |
189 | #ifdef GEN_TREES_H |
190 | local void gen_trees_header OF((void)); |
191 | #endif |
192 | |
193 | #ifndef DEBUG |
194 | # define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len) |
195 | /* Send a code of the given tree. c and tree must not have side effects */ |
196 | |
197 | #else /* DEBUG */ |
198 | # define send_code(s, c, tree) \ |
199 | { if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \ |
200 | send_bits(s, tree[c].Code, tree[c].Len); } |
201 | #endif |
202 | |
203 | /* =========================================================================== |
204 | * Output a short LSB first on the stream. |
205 | * IN assertion: there is enough room in pendingBuf. |
206 | */ |
207 | #define put_short(s, w) { \ |
208 | put_byte(s, (uch)((w) & 0xff)); \ |
209 | put_byte(s, (uch)((ush)(w) >> 8)); \ |
210 | } |
211 | |
212 | /* =========================================================================== |
213 | * Send a value on a given number of bits. |
214 | * IN assertion: length <= 16 and value fits in length bits. |
215 | */ |
216 | #ifdef DEBUG |
217 | local void send_bits OF((deflate_state *s, int value, int length)); |
218 | |
219 | /* |
220 | * @param value value to send |
221 | * @param length number of bits |
222 | */ |
223 | local void |
224 | send_bits(deflate_state *s, int value, int length) |
225 | { |
226 | Tracevv((stderr," l %2d v %4x " , length, value)); |
227 | Assert(length > 0 && length <= 15, "invalid length" ); |
228 | s->bits_sent += (ulg)length; |
229 | |
230 | /* If not enough room in bi_buf, use (valid) bits from bi_buf and |
231 | * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid)) |
232 | * unused bits in value. |
233 | */ |
234 | if (s->bi_valid > (int)Buf_size - length) { |
235 | s->bi_buf |= (value << s->bi_valid); |
236 | put_short(s, s->bi_buf); |
237 | s->bi_buf = (ush)value >> (Buf_size - s->bi_valid); |
238 | s->bi_valid += length - Buf_size; |
239 | } else { |
240 | s->bi_buf |= value << s->bi_valid; |
241 | s->bi_valid += length; |
242 | } |
243 | } |
244 | #else /* !DEBUG */ |
245 | |
246 | #define send_bits(s, value, length) \ |
247 | { int len = length;\ |
248 | if (s->bi_valid > (int)Buf_size - len) {\ |
249 | int val = value;\ |
250 | s->bi_buf |= (val << s->bi_valid);\ |
251 | put_short(s, s->bi_buf);\ |
252 | s->bi_buf = (ush)val >> (Buf_size - s->bi_valid);\ |
253 | s->bi_valid += len - Buf_size;\ |
254 | } else {\ |
255 | s->bi_buf |= (value) << s->bi_valid;\ |
256 | s->bi_valid += len;\ |
257 | }\ |
258 | } |
259 | #endif /* DEBUG */ |
260 | |
261 | |
262 | /* the arguments must not have side effects */ |
263 | |
264 | /* =========================================================================== |
265 | * Initialize the various 'constant' tables. |
266 | */ |
267 | local void |
268 | tr_static_init(void) |
269 | { |
270 | #if defined(GEN_TREES_H) || !defined(STDC) |
271 | static int static_init_done = 0; |
272 | int n; /* iterates over tree elements */ |
273 | int bits; /* bit counter */ |
274 | int length; /* length value */ |
275 | int code; /* code value */ |
276 | int dist; /* distance index */ |
277 | ush bl_count[MAX_BITS+1]; |
278 | /* number of codes at each bit length for an optimal tree */ |
279 | |
280 | if (static_init_done) return; |
281 | |
282 | /* For some embedded targets, global variables are not initialized: */ |
283 | static_l_desc.static_tree = static_ltree; |
284 | static_l_desc.extra_bits = extra_lbits; |
285 | static_d_desc.static_tree = static_dtree; |
286 | static_d_desc.extra_bits = extra_dbits; |
287 | static_bl_desc.extra_bits = extra_blbits; |
288 | |
289 | /* Initialize the mapping length (0..255) -> length code (0..28) */ |
290 | length = 0; |
291 | for (code = 0; code < LENGTH_CODES-1; code++) { |
292 | base_length[code] = length; |
293 | for (n = 0; n < (1<<extra_lbits[code]); n++) { |
294 | _length_code[length++] = (uch)code; |
295 | } |
296 | } |
297 | Assert (length == 256, "tr_static_init: length != 256" ); |
298 | /* Note that the length 255 (match length 258) can be represented |
299 | * in two different ways: code 284 + 5 bits or code 285, so we |
300 | * overwrite length_code[255] to use the best encoding: |
301 | */ |
302 | _length_code[length-1] = (uch)code; |
303 | |
304 | /* Initialize the mapping dist (0..32K) -> dist code (0..29) */ |
305 | dist = 0; |
306 | for (code = 0 ; code < 16; code++) { |
307 | base_dist[code] = dist; |
308 | for (n = 0; n < (1<<extra_dbits[code]); n++) { |
309 | _dist_code[dist++] = (uch)code; |
310 | } |
311 | } |
312 | Assert (dist == 256, "tr_static_init: dist != 256" ); |
313 | dist >>= 7; /* from now on, all distances are divided by 128 */ |
314 | for ( ; code < D_CODES; code++) { |
315 | base_dist[code] = dist << 7; |
316 | for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) { |
317 | _dist_code[256 + dist++] = (uch)code; |
318 | } |
319 | } |
320 | Assert (dist == 256, "tr_static_init: 256+dist != 512" ); |
321 | |
322 | /* Construct the codes of the static literal tree */ |
323 | for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0; |
324 | n = 0; |
325 | while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++; |
326 | while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++; |
327 | while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++; |
328 | while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++; |
329 | /* Codes 286 and 287 do not exist, but we must include them in the |
330 | * tree construction to get a canonical Huffman tree (longest code |
331 | * all ones) |
332 | */ |
333 | gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count); |
334 | |
335 | /* The static distance tree is trivial: */ |
336 | for (n = 0; n < D_CODES; n++) { |
337 | static_dtree[n].Len = 5; |
338 | static_dtree[n].Code = bi_reverse((unsigned)n, 5); |
339 | } |
340 | static_init_done = 1; |
341 | |
342 | # ifdef GEN_TREES_H |
343 | gen_trees_header(); |
344 | # endif |
345 | #endif /* defined(GEN_TREES_H) || !defined(STDC) */ |
346 | } |
347 | |
348 | /* =========================================================================== |
349 | * Genererate the file trees.h describing the static trees. |
350 | */ |
351 | #ifdef GEN_TREES_H |
352 | # ifndef DEBUG |
353 | # include <stdio.h> |
354 | # endif |
355 | |
356 | # define SEPARATOR(i, last, width) \ |
357 | ((i) == (last)? "\n};\n\n" : \ |
358 | ((i) % (width) == (width)-1 ? ",\n" : ", ")) |
359 | |
360 | void |
361 | gen_trees_header(void) |
362 | { |
363 | FILE *header = fopen("trees.h" , "w" ); |
364 | int i; |
365 | |
366 | Assert (header != NULL, "Can't open trees.h" ); |
367 | fprintf(header, |
368 | "/* header created automatically with -DGEN_TREES_H */\n\n" ); |
369 | |
370 | fprintf(header, "local const ct_data static_ltree[L_CODES+2] = {\n" ); |
371 | for (i = 0; i < L_CODES+2; i++) { |
372 | fprintf(header, "{{%3u},{%3u}}%s" , static_ltree[i].Code, |
373 | static_ltree[i].Len, SEPARATOR(i, L_CODES+1, 5)); |
374 | } |
375 | |
376 | fprintf(header, "local const ct_data static_dtree[D_CODES] = {\n" ); |
377 | for (i = 0; i < D_CODES; i++) { |
378 | fprintf(header, "{{%2u},{%2u}}%s" , static_dtree[i].Code, |
379 | static_dtree[i].Len, SEPARATOR(i, D_CODES-1, 5)); |
380 | } |
381 | |
382 | fprintf(header, "const uch _dist_code[DIST_CODE_LEN] = {\n" ); |
383 | for (i = 0; i < DIST_CODE_LEN; i++) { |
384 | fprintf(header, "%2u%s" , _dist_code[i], |
385 | SEPARATOR(i, DIST_CODE_LEN-1, 20)); |
386 | } |
387 | |
388 | fprintf(header, "const uch _length_code[MAX_MATCH-MIN_MATCH+1]= {\n" ); |
389 | for (i = 0; i < MAX_MATCH-MIN_MATCH+1; i++) { |
390 | fprintf(header, "%2u%s" , _length_code[i], |
391 | SEPARATOR(i, MAX_MATCH-MIN_MATCH, 20)); |
392 | } |
393 | |
394 | fprintf(header, "local const int base_length[LENGTH_CODES] = {\n" ); |
395 | for (i = 0; i < LENGTH_CODES; i++) { |
396 | fprintf(header, "%1u%s" , base_length[i], |
397 | SEPARATOR(i, LENGTH_CODES-1, 20)); |
398 | } |
399 | |
400 | fprintf(header, "local const int base_dist[D_CODES] = {\n" ); |
401 | for (i = 0; i < D_CODES; i++) { |
402 | fprintf(header, "%5u%s" , base_dist[i], |
403 | SEPARATOR(i, D_CODES-1, 10)); |
404 | } |
405 | |
406 | fclose(header); |
407 | } |
408 | #endif /* GEN_TREES_H */ |
409 | |
410 | /* =========================================================================== |
411 | * Initialize the tree data structures for a new zlib stream. |
412 | */ |
413 | void |
414 | _tr_init(deflate_state *s) |
415 | { |
416 | tr_static_init(); |
417 | |
418 | s->l_desc.dyn_tree = s->dyn_ltree; |
419 | s->l_desc.stat_desc = &static_l_desc; |
420 | |
421 | s->d_desc.dyn_tree = s->dyn_dtree; |
422 | s->d_desc.stat_desc = &static_d_desc; |
423 | |
424 | s->bl_desc.dyn_tree = s->bl_tree; |
425 | s->bl_desc.stat_desc = &static_bl_desc; |
426 | |
427 | s->bi_buf = 0; |
428 | s->bi_valid = 0; |
429 | s->last_eob_len = 8; /* enough lookahead for inflate */ |
430 | #ifdef DEBUG |
431 | s->compressed_len = 0L; |
432 | s->bits_sent = 0L; |
433 | #endif |
434 | |
435 | /* Initialize the first block of the first file: */ |
436 | init_block(s); |
437 | } |
438 | |
439 | /* =========================================================================== |
440 | * Initialize a new block. |
441 | */ |
442 | local void |
443 | init_block(deflate_state *s) |
444 | { |
445 | int n; /* iterates over tree elements */ |
446 | |
447 | /* Initialize the trees. */ |
448 | for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0; |
449 | for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0; |
450 | for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0; |
451 | |
452 | s->dyn_ltree[END_BLOCK].Freq = 1; |
453 | s->opt_len = s->static_len = 0L; |
454 | s->last_lit = s->matches = 0; |
455 | } |
456 | |
457 | #define SMALLEST 1 |
458 | /* Index within the heap array of least frequent node in the Huffman tree */ |
459 | |
460 | |
461 | /* =========================================================================== |
462 | * Remove the smallest element from the heap and recreate the heap with |
463 | * one less element. Updates heap and heap_len. |
464 | */ |
465 | #define pqremove(s, tree, top) \ |
466 | {\ |
467 | top = s->heap[SMALLEST]; \ |
468 | s->heap[SMALLEST] = s->heap[s->heap_len--]; \ |
469 | pqdownheap(s, tree, SMALLEST); \ |
470 | } |
471 | |
472 | /* =========================================================================== |
473 | * Compares to subtrees, using the tree depth as tie breaker when |
474 | * the subtrees have equal frequency. This minimizes the worst case length. |
475 | */ |
476 | #define smaller(tree, n, m, depth) \ |
477 | (tree[n].Freq < tree[m].Freq || \ |
478 | (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m])) |
479 | |
480 | /* =========================================================================== |
481 | * Restore the heap property by moving down the tree starting at node k, |
482 | * exchanging a node with the smallest of its two sons if necessary, stopping |
483 | * when the heap property is re-established (each father smaller than its |
484 | * two sons). |
485 | * |
486 | * @param tree the tree to restore |
487 | * @param k node to move down |
488 | */ |
489 | local void |
490 | pqdownheap(deflate_state *s, ct_data *tree, int k) |
491 | { |
492 | int v = s->heap[k]; |
493 | int j = k << 1; /* left son of k */ |
494 | while (j <= s->heap_len) { |
495 | /* Set j to the smallest of the two sons: */ |
496 | if (j < s->heap_len && |
497 | smaller(tree, s->heap[j+1], s->heap[j], s->depth)) { |
498 | j++; |
499 | } |
500 | /* Exit if v is smaller than both sons */ |
501 | if (smaller(tree, v, s->heap[j], s->depth)) break; |
502 | |
503 | /* Exchange v with the smallest son */ |
504 | s->heap[k] = s->heap[j]; k = j; |
505 | |
506 | /* And continue down the tree, setting j to the left son of k */ |
507 | j <<= 1; |
508 | } |
509 | s->heap[k] = v; |
510 | } |
511 | |
512 | /* =========================================================================== |
513 | * Compute the optimal bit lengths for a tree and update the total bit length |
514 | * for the current block. |
515 | * IN assertion: the fields freq and dad are set, heap[heap_max] and |
516 | * above are the tree nodes sorted by increasing frequency. |
517 | * OUT assertions: the field len is set to the optimal bit length, the |
518 | * array bl_count contains the frequencies for each bit length. |
519 | * The length opt_len is updated; static_len is also updated if stree is |
520 | * not null. |
521 | * @param desc the tree descriptor |
522 | */ |
523 | local void |
524 | gen_bitlen(deflate_state *s, tree_desc *desc) |
525 | { |
526 | ct_data *tree = desc->dyn_tree; |
527 | int max_code = desc->max_code; |
528 | const ct_data *stree = desc->stat_desc->static_tree; |
529 | const intf * = desc->stat_desc->extra_bits; |
530 | int base = desc->stat_desc->extra_base; |
531 | int max_length = desc->stat_desc->max_length; |
532 | int h; /* heap index */ |
533 | int n, m; /* iterate over the tree elements */ |
534 | int bits; /* bit length */ |
535 | int xbits; /* extra bits */ |
536 | ush f; /* frequency */ |
537 | int overflow = 0; /* number of elements with bit length too large */ |
538 | |
539 | for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0; |
540 | |
541 | /* In a first pass, compute the optimal bit lengths (which may |
542 | * overflow in the case of the bit length tree). |
543 | */ |
544 | tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */ |
545 | |
546 | for (h = s->heap_max+1; h < HEAP_SIZE; h++) { |
547 | n = s->heap[h]; |
548 | bits = tree[tree[n].Dad].Len + 1; |
549 | if (bits > max_length) { |
550 | bits = max_length; |
551 | overflow++; |
552 | } |
553 | tree[n].Len = (ush)bits; |
554 | /* We overwrite tree[n].Dad which is no longer needed */ |
555 | |
556 | if (n > max_code) continue; /* not a leaf node */ |
557 | |
558 | s->bl_count[bits]++; |
559 | xbits = 0; |
560 | if (n >= base) xbits = extra[n-base]; |
561 | f = tree[n].Freq; |
562 | s->opt_len += (ulg)f * (bits + xbits); |
563 | if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits); |
564 | } |
565 | if (overflow == 0) return; |
566 | |
567 | Trace((stderr,"\nbit length overflow\n" )); |
568 | /* This happens for example on obj2 and pic of the Calgary corpus */ |
569 | |
570 | /* Find the first bit length which could increase: */ |
571 | do { |
572 | bits = max_length-1; |
573 | while (s->bl_count[bits] == 0) bits--; |
574 | s->bl_count[bits]--; /* move one leaf down the tree */ |
575 | s->bl_count[bits+1] += 2; /* move one overflow item as its brother */ |
576 | s->bl_count[max_length]--; |
577 | /* The brother of the overflow item also moves one step up, |
578 | * but this does not affect bl_count[max_length] |
579 | */ |
580 | overflow -= 2; |
581 | } while (overflow > 0); |
582 | |
583 | /* Now recompute all bit lengths, scanning in increasing frequency. |
584 | * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all |
585 | * lengths instead of fixing only the wrong ones. This idea is taken |
586 | * from 'ar' written by Haruhiko Okumura.) |
587 | */ |
588 | for (bits = max_length; bits != 0; bits--) { |
589 | n = s->bl_count[bits]; |
590 | while (n != 0) { |
591 | m = s->heap[--h]; |
592 | if (m > max_code) continue; |
593 | if ((unsigned) tree[m].Len != (unsigned) bits) { |
594 | Trace((stderr,"code %d bits %d->%d\n" , m, tree[m].Len, bits)); |
595 | s->opt_len += ((long)bits - (long)tree[m].Len) |
596 | *(long)tree[m].Freq; |
597 | tree[m].Len = (ush)bits; |
598 | } |
599 | n--; |
600 | } |
601 | } |
602 | } |
603 | |
604 | /* =========================================================================== |
605 | * Generate the codes for a given tree and bit counts (which need not be |
606 | * optimal). |
607 | * IN assertion: the array bl_count contains the bit length statistics for |
608 | * the given tree and the field len is set for all tree elements. |
609 | * OUT assertion: the field code is set for all tree elements of non |
610 | * zero code length. |
611 | * |
612 | * @param tree the tree to decorate |
613 | * @param max_count largest code with non zero frequency |
614 | * @param bl_count number of codes at each bit length |
615 | */ |
616 | local void |
617 | gen_codes(ct_data *tree, int max_code, ushf *bl_count) |
618 | { |
619 | ush next_code[MAX_BITS+1]; /* next code value for each bit length */ |
620 | ush code = 0; /* running code value */ |
621 | int bits; /* bit index */ |
622 | int n; /* code index */ |
623 | |
624 | /* The distribution counts are first used to generate the code values |
625 | * without bit reversal. |
626 | */ |
627 | for (bits = 1; bits <= MAX_BITS; bits++) { |
628 | next_code[bits] = code = (ush)((code + bl_count[bits-1]) << 1); |
629 | } |
630 | /* Check that the bit counts in bl_count are consistent. The last code |
631 | * must be all ones. |
632 | */ |
633 | Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1, |
634 | "inconsistent bit counts" ); |
635 | Tracev((stderr,"\ngen_codes: max_code %d " , max_code)); |
636 | |
637 | for (n = 0; n <= max_code; n++) { |
638 | int len = tree[n].Len; |
639 | if (len == 0) continue; |
640 | /* Now reverse the bits */ |
641 | tree[n].Code = (ush)bi_reverse(value: next_code[len]++, length: len); |
642 | |
643 | Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) " , |
644 | n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1)); |
645 | } |
646 | } |
647 | |
648 | /* =========================================================================== |
649 | * Construct one Huffman tree and assigns the code bit strings and lengths. |
650 | * Update the total bit length for the current block. |
651 | * IN assertion: the field freq is set for all tree elements. |
652 | * OUT assertions: the fields len and code are set to the optimal bit length |
653 | * and corresponding code. The length opt_len is updated; static_len is |
654 | * also updated if stree is not null. The field max_code is set. |
655 | * |
656 | * @param desc the tree descriptor |
657 | */ |
658 | local void |
659 | build_tree(deflate_state *s, tree_desc *desc) |
660 | { |
661 | ct_data *tree = desc->dyn_tree; |
662 | const ct_data *stree = desc->stat_desc->static_tree; |
663 | int elems = desc->stat_desc->elems; |
664 | int n, m; /* iterate over heap elements */ |
665 | int max_code = -1; /* largest code with non zero frequency */ |
666 | int node; /* new node being created */ |
667 | |
668 | /* Construct the initial heap, with least frequent element in |
669 | * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1]. |
670 | * heap[0] is not used. |
671 | */ |
672 | s->heap_len = 0; |
673 | s->heap_max = HEAP_SIZE; |
674 | |
675 | for (n = 0; n < elems; n++) { |
676 | if (tree[n].Freq != 0) { |
677 | s->heap[++(s->heap_len)] = max_code = n; |
678 | s->depth[n] = 0; |
679 | } else { |
680 | tree[n].Len = 0; |
681 | } |
682 | } |
683 | |
684 | /* The pkzip format requires that at least one distance code exists, |
685 | * and that at least one bit should be sent even if there is only one |
686 | * possible code. So to avoid special checks later on we force at least |
687 | * two codes of non zero frequency. |
688 | */ |
689 | while (s->heap_len < 2) { |
690 | node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0); |
691 | tree[node].Freq = 1; |
692 | s->depth[node] = 0; |
693 | s->opt_len--; if (stree) s->static_len -= stree[node].Len; |
694 | /* node is 0 or 1 so it does not have extra bits */ |
695 | } |
696 | desc->max_code = max_code; |
697 | |
698 | /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree, |
699 | * establish sub-heaps of increasing lengths: |
700 | */ |
701 | for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, k: n); |
702 | |
703 | /* Construct the Huffman tree by repeatedly combining the least two |
704 | * frequent nodes. |
705 | */ |
706 | node = elems; /* next internal node of the tree */ |
707 | do { |
708 | pqremove(s, tree, n); /* n = node of least frequency */ |
709 | m = s->heap[SMALLEST]; /* m = node of next least frequency */ |
710 | |
711 | s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */ |
712 | s->heap[--(s->heap_max)] = m; |
713 | |
714 | /* Create a new node father of n and m */ |
715 | tree[node].Freq = tree[n].Freq + tree[m].Freq; |
716 | s->depth[node] = (uch)((s->depth[n] >= s->depth[m] ? |
717 | s->depth[n] : s->depth[m]) + 1); |
718 | tree[n].Dad = tree[m].Dad = (ush)node; |
719 | #ifdef DUMP_BL_TREE |
720 | if (tree == s->bl_tree) { |
721 | fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)" , |
722 | node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq); |
723 | } |
724 | #endif |
725 | /* and insert the new node in the heap */ |
726 | s->heap[SMALLEST] = node++; |
727 | pqdownheap(s, tree, SMALLEST); |
728 | |
729 | } while (s->heap_len >= 2); |
730 | |
731 | s->heap[--(s->heap_max)] = s->heap[SMALLEST]; |
732 | |
733 | /* At this point, the fields freq and dad are set. We can now |
734 | * generate the bit lengths. |
735 | */ |
736 | gen_bitlen(s, desc: (tree_desc *)desc); |
737 | |
738 | /* The field len is now set, we can generate the bit codes */ |
739 | gen_codes (tree: (ct_data *)tree, max_code, bl_count: s->bl_count); |
740 | } |
741 | |
742 | /* =========================================================================== |
743 | * Scan a literal or distance tree to determine the frequencies of the codes |
744 | * in the bit length tree. |
745 | * |
746 | * @param tree the tree to be scanned |
747 | * @param max_code and its largest code of non zero frequency |
748 | */ |
749 | local void |
750 | scan_tree(deflate_state *s, ct_data *tree, int max_code) |
751 | { |
752 | int n; /* iterates over all tree elements */ |
753 | int prevlen = -1; /* last emitted length */ |
754 | int curlen; /* length of current code */ |
755 | int nextlen = tree[0].Len; /* length of next code */ |
756 | int count = 0; /* repeat count of the current code */ |
757 | int max_count = 7; /* max repeat count */ |
758 | int min_count = 4; /* min repeat count */ |
759 | |
760 | if (nextlen == 0) { |
761 | max_count = 138; |
762 | min_count = 3; |
763 | } |
764 | tree[max_code+1].Len = (ush)0xffff; /* guard */ |
765 | |
766 | for (n = 0; n <= max_code; n++) { |
767 | curlen = nextlen; nextlen = tree[n+1].Len; |
768 | if (++count < max_count && curlen == nextlen) { |
769 | continue; |
770 | } else if (count < min_count) { |
771 | s->bl_tree[curlen].Freq += count; |
772 | } else if (curlen != 0) { |
773 | if (curlen != prevlen) s->bl_tree[curlen].Freq++; |
774 | s->bl_tree[REP_3_6].Freq++; |
775 | } else if (count <= 10) { |
776 | s->bl_tree[REPZ_3_10].Freq++; |
777 | } else { |
778 | s->bl_tree[REPZ_11_138].Freq++; |
779 | } |
780 | count = 0; prevlen = curlen; |
781 | if (nextlen == 0) { |
782 | max_count = 138; |
783 | min_count = 3; |
784 | } else if (curlen == nextlen) { |
785 | max_count = 6; |
786 | min_count = 3; |
787 | } else { |
788 | max_count = 7; |
789 | min_count = 4; |
790 | } |
791 | } |
792 | } |
793 | |
794 | /* =========================================================================== |
795 | * Send a literal or distance tree in compressed form, using the codes in |
796 | * bl_tree. |
797 | * |
798 | * @param tree the tree to be scanned |
799 | * @param max_code and its largest code of non zero frequency |
800 | */ |
801 | local void |
802 | send_tree( deflate_state *s, ct_data *tree, int max_code) |
803 | { |
804 | int n; /* iterates over all tree elements */ |
805 | int prevlen = -1; /* last emitted length */ |
806 | int curlen; /* length of current code */ |
807 | int nextlen = tree[0].Len; /* length of next code */ |
808 | int count = 0; /* repeat count of the current code */ |
809 | int max_count = 7; /* max repeat count */ |
810 | int min_count = 4; /* min repeat count */ |
811 | |
812 | /* tree[max_code+1].Len = -1; */ /* guard already set */ |
813 | if (nextlen == 0) { |
814 | max_count = 138; |
815 | min_count = 3; |
816 | } |
817 | |
818 | for (n = 0; n <= max_code; n++) { |
819 | curlen = nextlen; nextlen = tree[n+1].Len; |
820 | if (++count < max_count && curlen == nextlen) { |
821 | continue; |
822 | } else if (count < min_count) { |
823 | do { send_code(s, curlen, s->bl_tree); } while (--count != 0); |
824 | |
825 | } else if (curlen != 0) { |
826 | if (curlen != prevlen) { |
827 | send_code(s, curlen, s->bl_tree); count--; |
828 | } |
829 | Assert(count >= 3 && count <= 6, " 3_6?" ); |
830 | send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2); |
831 | |
832 | } else if (count <= 10) { |
833 | send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3); |
834 | |
835 | } else { |
836 | send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7); |
837 | } |
838 | count = 0; prevlen = curlen; |
839 | if (nextlen == 0) { |
840 | max_count = 138; |
841 | min_count = 3; |
842 | } else if (curlen == nextlen) { |
843 | max_count = 6; |
844 | min_count = 3; |
845 | } else { |
846 | max_count = 7; |
847 | min_count = 4; |
848 | } |
849 | } |
850 | } |
851 | |
852 | /* =========================================================================== |
853 | * Construct the Huffman tree for the bit lengths and return the index in |
854 | * bl_order of the last bit length code to send. |
855 | */ |
856 | local int |
857 | build_bl_tree(deflate_state *s) |
858 | { |
859 | int max_blindex; /* index of last bit length code of non zero freq */ |
860 | |
861 | /* Determine the bit length frequencies for literal and distance trees */ |
862 | scan_tree(s, tree: (ct_data *)s->dyn_ltree, max_code: s->l_desc.max_code); |
863 | scan_tree(s, tree: (ct_data *)s->dyn_dtree, max_code: s->d_desc.max_code); |
864 | |
865 | /* Build the bit length tree: */ |
866 | build_tree(s, desc: (tree_desc *)(&(s->bl_desc))); |
867 | /* opt_len now includes the length of the tree representations, except |
868 | * the lengths of the bit lengths codes and the 5+5+4 bits for the counts. |
869 | */ |
870 | |
871 | /* Determine the number of bit length codes to send. The pkzip format |
872 | * requires that at least 4 bit length codes be sent. (appnote.txt says |
873 | * 3 but the actual value used is 4.) |
874 | */ |
875 | for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) { |
876 | if (s->bl_tree[bl_order[max_blindex]].Len != 0) break; |
877 | } |
878 | /* Update opt_len to include the bit length tree and counts */ |
879 | s->opt_len += 3*(max_blindex+1) + 5+5+4; |
880 | Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld" , |
881 | s->opt_len, s->static_len)); |
882 | |
883 | return max_blindex; |
884 | } |
885 | |
886 | /* =========================================================================== |
887 | * Send the header for a block using dynamic Huffman trees: the counts, the |
888 | * lengths of the bit length codes, the literal tree and the distance tree. |
889 | * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4. |
890 | * |
891 | * @param lcodes number of codes for each tree |
892 | * @param dcodes number of codes for each tree |
893 | * @param blcodes number of codes for each tree |
894 | */ |
895 | local void |
896 | send_all_trees(deflate_state *s, int lcodes, int dcodes, int blcodes) |
897 | { |
898 | int rank; /* index in bl_order */ |
899 | |
900 | Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes" ); |
901 | Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES, |
902 | "too many codes" ); |
903 | Tracev((stderr, "\nbl counts: " )); |
904 | send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */ |
905 | send_bits(s, dcodes-1, 5); |
906 | send_bits(s, blcodes-4, 4); /* not -3 as stated in appnote.txt */ |
907 | for (rank = 0; rank < blcodes; rank++) { |
908 | Tracev((stderr, "\nbl code %2d " , bl_order[rank])); |
909 | send_bits(s, s->bl_tree[bl_order[rank]].Len, 3); |
910 | } |
911 | Tracev((stderr, "\nbl tree: sent %ld" , s->bits_sent)); |
912 | |
913 | send_tree(s, tree: (ct_data *)s->dyn_ltree, max_code: lcodes-1); /* literal tree */ |
914 | Tracev((stderr, "\nlit tree: sent %ld" , s->bits_sent)); |
915 | |
916 | send_tree(s, tree: (ct_data *)s->dyn_dtree, max_code: dcodes-1); /* distance tree */ |
917 | Tracev((stderr, "\ndist tree: sent %ld" , s->bits_sent)); |
918 | } |
919 | |
920 | /* =========================================================================== |
921 | * Send a stored block |
922 | * |
923 | * @param buf input block |
924 | * @param stored_len length of input block |
925 | * @param eof true if this is the last block for a file |
926 | */ |
927 | void |
928 | _tr_stored_block(deflate_state *s, charf *buf, ulg stored_len, int eof) |
929 | { |
930 | send_bits(s, (STORED_BLOCK<<1)+eof, 3); /* send block type */ |
931 | #ifdef DEBUG |
932 | s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L; |
933 | s->compressed_len += (stored_len + 4) << 3; |
934 | #endif |
935 | copy_block(s, buf, len: (unsigned)stored_len, header: 1); /* with header */ |
936 | } |
937 | |
938 | /* =========================================================================== |
939 | * Send one empty static block to give enough lookahead for inflate. |
940 | * This takes 10 bits, of which 7 may remain in the bit buffer. |
941 | * The current inflate code requires 9 bits of lookahead. If the |
942 | * last two codes for the previous block (real code plus EOB) were coded |
943 | * on 5 bits or less, inflate may have only 5+3 bits of lookahead to decode |
944 | * the last real code. In this case we send two empty static blocks instead |
945 | * of one. (There are no problems if the previous block is stored or fixed.) |
946 | * To simplify the code, we assume the worst case of last real code encoded |
947 | * on one bit only. |
948 | */ |
949 | void |
950 | _tr_align(deflate_state *s) |
951 | { |
952 | send_bits(s, STATIC_TREES<<1, 3); |
953 | send_code(s, END_BLOCK, static_ltree); |
954 | #ifdef DEBUG |
955 | s->compressed_len += 10L; /* 3 for block type, 7 for EOB */ |
956 | #endif |
957 | bi_flush(s); |
958 | /* Of the 10 bits for the empty block, we have already sent |
959 | * (10 - bi_valid) bits. The lookahead for the last real code (before |
960 | * the EOB of the previous block) was thus at least one plus the length |
961 | * of the EOB plus what we have just sent of the empty static block. |
962 | */ |
963 | if (1 + s->last_eob_len + 10 - s->bi_valid < 9) { |
964 | send_bits(s, STATIC_TREES<<1, 3); |
965 | send_code(s, END_BLOCK, static_ltree); |
966 | #ifdef DEBUG |
967 | s->compressed_len += 10L; |
968 | #endif |
969 | bi_flush(s); |
970 | } |
971 | s->last_eob_len = 7; |
972 | } |
973 | |
974 | /* =========================================================================== |
975 | * Determine the best encoding for the current block: dynamic trees, static |
976 | * trees or store, and output the encoded block to the zip file. |
977 | * |
978 | * @param buf input block, or NULL if too old |
979 | * @param stored_len length of input block |
980 | * @param eof true if this is the last block for a file |
981 | */ |
982 | void |
983 | _tr_flush_block(deflate_state *s, charf *buf, ulg stored_len, int eof) |
984 | { |
985 | ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */ |
986 | int max_blindex = 0; /* index of last bit length code of non zero freq */ |
987 | |
988 | /* Build the Huffman trees unless a stored block is forced */ |
989 | if (s->level > 0) { |
990 | |
991 | /* Check if the file is binary or text */ |
992 | if (stored_len > 0 && s->strm->data_type == Z_UNKNOWN) |
993 | set_data_type(s); |
994 | |
995 | /* Construct the literal and distance trees */ |
996 | build_tree(s, desc: (tree_desc *)(&(s->l_desc))); |
997 | Tracev((stderr, "\nlit data: dyn %ld, stat %ld" , s->opt_len, |
998 | s->static_len)); |
999 | |
1000 | build_tree(s, desc: (tree_desc *)(&(s->d_desc))); |
1001 | Tracev((stderr, "\ndist data: dyn %ld, stat %ld" , s->opt_len, |
1002 | s->static_len)); |
1003 | /* At this point, opt_len and static_len are the total bit lengths of |
1004 | * the compressed block data, excluding the tree representations. |
1005 | */ |
1006 | |
1007 | /* Build the bit length tree for the above two trees, and get the index |
1008 | * in bl_order of the last bit length code to send. |
1009 | */ |
1010 | max_blindex = build_bl_tree(s); |
1011 | |
1012 | /* Determine the best encoding. Compute the block lengths in bytes. */ |
1013 | opt_lenb = (s->opt_len+3+7)>>3; |
1014 | static_lenb = (s->static_len+3+7)>>3; |
1015 | |
1016 | Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u " , |
1017 | opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len, |
1018 | s->last_lit)); |
1019 | |
1020 | if (static_lenb <= opt_lenb) opt_lenb = static_lenb; |
1021 | |
1022 | } else { |
1023 | Assert(buf != (char*)0, "lost buf" ); |
1024 | opt_lenb = static_lenb = stored_len + 5; /* force a stored block */ |
1025 | } |
1026 | |
1027 | #ifdef FORCE_STORED |
1028 | if (buf != (char*)0) { /* force stored block */ |
1029 | #else |
1030 | if (stored_len+4 <= opt_lenb && buf != (char*)0) { |
1031 | /* 4: two words for the lengths */ |
1032 | #endif |
1033 | /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE. |
1034 | * Otherwise we can't have processed more than WSIZE input bytes since |
1035 | * the last block flush, because compression would have been |
1036 | * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to |
1037 | * transform a block into a stored block. |
1038 | */ |
1039 | _tr_stored_block(s, buf, stored_len, eof); |
1040 | |
1041 | #ifdef FORCE_STATIC |
1042 | } else if (static_lenb >= 0) { /* force static trees */ |
1043 | #else |
1044 | } else if (s->strategy == Z_FIXED || static_lenb == opt_lenb) { |
1045 | #endif |
1046 | send_bits(s, (STATIC_TREES<<1)+eof, 3); |
1047 | compress_block(s, ltree: (ct_data *)static_ltree, dtree: (ct_data *)static_dtree); |
1048 | #ifdef DEBUG |
1049 | s->compressed_len += 3 + s->static_len; |
1050 | #endif |
1051 | } else { |
1052 | send_bits(s, (DYN_TREES<<1)+eof, 3); |
1053 | send_all_trees(s, lcodes: s->l_desc.max_code+1, dcodes: s->d_desc.max_code+1, |
1054 | blcodes: max_blindex+1); |
1055 | compress_block(s, ltree: (ct_data *)s->dyn_ltree, dtree: (ct_data *)s->dyn_dtree); |
1056 | #ifdef DEBUG |
1057 | s->compressed_len += 3 + s->opt_len; |
1058 | #endif |
1059 | } |
1060 | Assert (s->compressed_len == s->bits_sent, "bad compressed size" ); |
1061 | /* The above check is made mod 2^32, for files larger than 512 MB |
1062 | * and uLong implemented on 32 bits. |
1063 | */ |
1064 | init_block(s); |
1065 | |
1066 | if (eof) { |
1067 | bi_windup(s); |
1068 | #ifdef DEBUG |
1069 | s->compressed_len += 7; /* align on byte boundary */ |
1070 | #endif |
1071 | } |
1072 | Tracev((stderr,"\ncomprlen %lu(%lu) " , s->compressed_len>>3, |
1073 | s->compressed_len-7*eof)); |
1074 | } |
1075 | |
1076 | /* =========================================================================== |
1077 | * Save the match info and tally the frequency counts. Return true if |
1078 | * the current block must be flushed. |
1079 | * |
1080 | * @param dist distance of matched string |
1081 | * @param lc match length-MIN_MATCH or unmatched char (if dist==0) |
1082 | */ |
1083 | int |
1084 | _tr_tally(deflate_state *s, unsigned dist, unsigned lc) |
1085 | { |
1086 | s->d_buf[s->last_lit] = (ush)dist; |
1087 | s->l_buf[s->last_lit++] = (uch)lc; |
1088 | if (dist == 0) { |
1089 | /* lc is the unmatched char */ |
1090 | s->dyn_ltree[lc].Freq++; |
1091 | } else { |
1092 | s->matches++; |
1093 | /* Here, lc is the match length - MIN_MATCH */ |
1094 | dist--; /* dist = match distance - 1 */ |
1095 | Assert((ush)dist < (ush)MAX_DIST(s) && |
1096 | (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) && |
1097 | (ush)d_code(dist) < (ush)D_CODES, "_tr_tally: bad match" ); |
1098 | |
1099 | s->dyn_ltree[_length_code[lc]+LITERALS+1].Freq++; |
1100 | s->dyn_dtree[d_code(dist)].Freq++; |
1101 | } |
1102 | |
1103 | #ifdef TRUNCATE_BLOCK |
1104 | /* Try to guess if it is profitable to stop the current block here */ |
1105 | if ((s->last_lit & 0x1fff) == 0 && s->level > 2) { |
1106 | /* Compute an upper bound for the compressed length */ |
1107 | ulg out_length = (ulg)s->last_lit*8L; |
1108 | ulg in_length = (ulg)((long)s->strstart - s->block_start); |
1109 | int dcode; |
1110 | for (dcode = 0; dcode < D_CODES; dcode++) { |
1111 | out_length += (ulg)s->dyn_dtree[dcode].Freq * |
1112 | (5L+extra_dbits[dcode]); |
1113 | } |
1114 | out_length >>= 3; |
1115 | Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) " , |
1116 | s->last_lit, in_length, out_length, |
1117 | 100L - out_length*100L/in_length)); |
1118 | if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1; |
1119 | } |
1120 | #endif |
1121 | return (s->last_lit == s->lit_bufsize-1); |
1122 | /* We avoid equality with lit_bufsize because of wraparound at 64K |
1123 | * on 16 bit machines and because stored blocks are restricted to |
1124 | * 64K-1 bytes. |
1125 | */ |
1126 | } |
1127 | |
1128 | /* =========================================================================== |
1129 | * Send the block data compressed using the given Huffman trees |
1130 | * |
1131 | * @param ltree literal tree |
1132 | * @param dtree distance tree |
1133 | */ |
1134 | |
1135 | __abortlike __printflike(1, 2) |
1136 | extern void panic(const char *string, ...); |
1137 | |
1138 | |
1139 | local void |
1140 | compress_block(deflate_state *s, ct_data *ltree, ct_data *dtree) |
1141 | { |
1142 | unsigned dist; /* distance of matched string */ |
1143 | int lc; /* match length or unmatched char (if dist == 0) */ |
1144 | unsigned lx = 0; /* running index in l_buf */ |
1145 | unsigned code; /* the code to send */ |
1146 | int ; /* number of extra bits to send */ |
1147 | |
1148 | if (s->last_lit != 0) do { |
1149 | |
1150 | if (&s->pending_buf[s->pending] > (Bytef *)&s->d_buf[lx]) { |
1151 | panic(string: "zlib deflate" ); |
1152 | } |
1153 | dist = s->d_buf[lx]; |
1154 | lc = s->l_buf[lx++]; |
1155 | if (dist == 0) { |
1156 | send_code(s, lc, ltree); /* send a literal byte */ |
1157 | Tracecv(isgraph(lc), (stderr," '%c' " , lc)); |
1158 | } else { |
1159 | /* Here, lc is the match length - MIN_MATCH */ |
1160 | code = _length_code[lc]; |
1161 | send_code(s, code+LITERALS+1, ltree); /* send the length code */ |
1162 | extra = extra_lbits[code]; |
1163 | if (extra != 0) { |
1164 | lc -= base_length[code]; |
1165 | send_bits(s, lc, extra); /* send the extra length bits */ |
1166 | } |
1167 | dist--; /* dist is now the match distance - 1 */ |
1168 | code = d_code(dist); |
1169 | Assert (code < D_CODES, "bad d_code" ); |
1170 | |
1171 | send_code(s, code, dtree); /* send the distance code */ |
1172 | extra = extra_dbits[code]; |
1173 | if (extra != 0) { |
1174 | dist -= base_dist[code]; |
1175 | send_bits(s, dist, extra); /* send the extra distance bits */ |
1176 | } |
1177 | } /* literal or match pair ? */ |
1178 | |
1179 | /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */ |
1180 | Assert((uInt)(s->pending) < s->lit_bufsize + 2*lx, |
1181 | "pendingBuf overflow" ); |
1182 | |
1183 | } while (lx < s->last_lit); |
1184 | |
1185 | send_code(s, END_BLOCK, ltree); |
1186 | s->last_eob_len = ltree[END_BLOCK].Len; |
1187 | } |
1188 | |
1189 | /* =========================================================================== |
1190 | * Set the data type to BINARY or TEXT, using a crude approximation: |
1191 | * set it to Z_TEXT if all symbols are either printable characters (33 to 255) |
1192 | * or white spaces (9 to 13, or 32); or set it to Z_BINARY otherwise. |
1193 | * IN assertion: the fields Freq of dyn_ltree are set. |
1194 | */ |
1195 | local void |
1196 | set_data_type(deflate_state *s) |
1197 | { |
1198 | int n; |
1199 | |
1200 | for (n = 0; n < 9; n++) |
1201 | if (s->dyn_ltree[n].Freq != 0) |
1202 | break; |
1203 | if (n == 9) |
1204 | for (n = 14; n < 32; n++) |
1205 | if (s->dyn_ltree[n].Freq != 0) |
1206 | break; |
1207 | s->strm->data_type = (n == 32) ? Z_TEXT : Z_BINARY; |
1208 | } |
1209 | |
1210 | /* =========================================================================== |
1211 | * Reverse the first len bits of a code, using straightforward code (a faster |
1212 | * method would use a table) |
1213 | * IN assertion: 1 <= len <= 15 |
1214 | * |
1215 | * @param code the value to invert |
1216 | * @param len its bit length |
1217 | */ |
1218 | local unsigned |
1219 | bi_reverse(unsigned code, int len) |
1220 | { |
1221 | unsigned res = 0; |
1222 | do { |
1223 | res |= code & 1; |
1224 | code >>= 1; |
1225 | res <<= 1; |
1226 | } while (--len > 0); |
1227 | return res >> 1; |
1228 | } |
1229 | |
1230 | /* =========================================================================== |
1231 | * Flush the bit buffer, keeping at most 7 bits in it. |
1232 | */ |
1233 | local void |
1234 | bi_flush(deflate_state *s) |
1235 | { |
1236 | if (s->bi_valid == 16) { |
1237 | put_short(s, s->bi_buf); |
1238 | s->bi_buf = 0; |
1239 | s->bi_valid = 0; |
1240 | } else if (s->bi_valid >= 8) { |
1241 | put_byte(s, (Byte)s->bi_buf); |
1242 | s->bi_buf >>= 8; |
1243 | s->bi_valid -= 8; |
1244 | } |
1245 | } |
1246 | |
1247 | /* =========================================================================== |
1248 | * Flush the bit buffer and align the output on a byte boundary |
1249 | */ |
1250 | local void |
1251 | bi_windup(deflate_state *s) |
1252 | { |
1253 | if (s->bi_valid > 8) { |
1254 | put_short(s, s->bi_buf); |
1255 | } else if (s->bi_valid > 0) { |
1256 | put_byte(s, (Byte)s->bi_buf); |
1257 | } |
1258 | s->bi_buf = 0; |
1259 | s->bi_valid = 0; |
1260 | #ifdef DEBUG |
1261 | s->bits_sent = (s->bits_sent+7) & ~7; |
1262 | #endif |
1263 | } |
1264 | |
1265 | /* =========================================================================== |
1266 | * Copy a stored block, storing first the length and its |
1267 | * one's complement if requested. |
1268 | * |
1269 | * @param buf the input data |
1270 | * @param len its length |
1271 | * @param header true if block header must be written |
1272 | */ |
1273 | local void |
1274 | copy_block(deflate_state *s, charf *buf, unsigned len, int ) |
1275 | { |
1276 | bi_windup(s); /* align on byte boundary */ |
1277 | s->last_eob_len = 8; /* enough lookahead for inflate */ |
1278 | |
1279 | if (header) { |
1280 | put_short(s, (ush)len); |
1281 | put_short(s, (ush)~len); |
1282 | #ifdef DEBUG |
1283 | s->bits_sent += 2*16; |
1284 | #endif |
1285 | } |
1286 | #ifdef DEBUG |
1287 | s->bits_sent += (ulg)len<<3; |
1288 | #endif |
1289 | while (len--) { |
1290 | put_byte(s, *buf++); |
1291 | } |
1292 | } |
1293 | |