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1 | /* trees.c -- output deflated data using Huffman coding | |
2 | * Copyright (C) 1995-2002 Jean-loup Gailly | |
3 | * For conditions of distribution and use, see copyright notice in zlib.h | |
4 | */ | |
5 | ||
6 | /* | |
7 | * ALGORITHM | |
8 | * | |
9 | * The "deflation" process uses several Huffman trees. The more | |
10 | * common source values are represented by shorter bit sequences. | |
11 | * | |
12 | * Each code tree is stored in a compressed form which is itself | |
13 | * a Huffman encoding of the lengths of all the code strings (in | |
14 | * ascending order by source values). The actual code strings are | |
15 | * reconstructed from the lengths in the inflate process, as described | |
16 | * in the deflate specification. | |
17 | * | |
18 | * REFERENCES | |
19 | * | |
20 | * Deutsch, L.P.,"'Deflate' Compressed Data Format Specification". | |
21 | * Available in ftp.uu.net:/pub/archiving/zip/doc/deflate-1.1.doc | |
22 | * | |
23 | * Storer, James A. | |
24 | * Data Compression: Methods and Theory, pp. 49-50. | |
25 | * Computer Science Press, 1988. ISBN 0-7167-8156-5. | |
26 | * | |
27 | * Sedgewick, R. | |
28 | * Algorithms, p290. | |
29 | * Addison-Wesley, 1983. ISBN 0-201-06672-6. | |
30 | */ | |
31 | ||
32 | /* @(#) $Id$ */ | |
33 | ||
34 | /* #define GEN_TREES_H */ | |
35 | ||
36 | #include "deflate.h" | |
37 | ||
38 | #ifdef __WXDEBUG__ | |
39 | # include <ctype.h> | |
40 | #endif | |
41 | ||
42 | /* =========================================================================== | |
43 | * Constants | |
44 | */ | |
45 | ||
46 | #define MAX_BL_BITS 7 | |
47 | /* Bit length codes must not exceed MAX_BL_BITS bits */ | |
48 | ||
49 | #define END_BLOCK 256 | |
50 | /* end of block literal code */ | |
51 | ||
52 | #define REP_3_6 16 | |
53 | /* repeat previous bit length 3-6 times (2 bits of repeat count) */ | |
54 | ||
55 | #define REPZ_3_10 17 | |
56 | /* repeat a zero length 3-10 times (3 bits of repeat count) */ | |
57 | ||
58 | #define REPZ_11_138 18 | |
59 | /* repeat a zero length 11-138 times (7 bits of repeat count) */ | |
60 | ||
61 | local const int extra_lbits[LENGTH_CODES] /* extra bits for each length code */ | |
62 | = {0,0,0,0,0,0,0,0,1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4,5,5,5,5,0}; | |
63 | ||
64 | local const int extra_dbits[D_CODES] /* extra bits for each distance code */ | |
65 | = {0,0,0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13}; | |
66 | ||
67 | local const int extra_blbits[BL_CODES]/* extra bits for each bit length code */ | |
68 | = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7}; | |
69 | ||
70 | local const uch bl_order[BL_CODES] | |
71 | = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15}; | |
72 | /* The lengths of the bit length codes are sent in order of decreasing | |
73 | * probability, to avoid transmitting the lengths for unused bit length codes. | |
74 | */ | |
75 | ||
76 | #define Buf_size (8 * 2*sizeof(char)) | |
77 | /* Number of bits used within bi_buf. (bi_buf might be implemented on | |
78 | * more than 16 bits on some systems.) | |
79 | */ | |
80 | ||
81 | /* =========================================================================== | |
82 | * Local data. These are initialized only once. | |
83 | */ | |
84 | ||
85 | #define DIST_CODE_LEN 512 /* see definition of array dist_code below */ | |
86 | ||
87 | #if defined(GEN_TREES_H) || !defined(STDC) | |
88 | /* non ANSI compilers may not accept trees.h */ | |
89 | ||
90 | local ct_data static_ltree[L_CODES+2]; | |
91 | /* The static literal tree. Since the bit lengths are imposed, there is no | |
92 | * need for the L_CODES extra codes used during heap construction. However | |
93 | * The codes 286 and 287 are needed to build a canonical tree (see _tr_init | |
94 | * below). | |
95 | */ | |
96 | ||
97 | local ct_data static_dtree[D_CODES]; | |
98 | /* The static distance tree. (Actually a trivial tree since all codes use | |
99 | * 5 bits.) | |
100 | */ | |
101 | ||
102 | uch _dist_code[DIST_CODE_LEN]; | |
103 | /* Distance codes. The first 256 values correspond to the distances | |
104 | * 3 .. 258, the last 256 values correspond to the top 8 bits of | |
105 | * the 15 bit distances. | |
106 | */ | |
107 | ||
108 | uch _length_code[MAX_MATCH-MIN_MATCH+1]; | |
109 | /* length code for each normalized match length (0 == MIN_MATCH) */ | |
110 | ||
111 | local int base_length[LENGTH_CODES]; | |
112 | /* First normalized length for each code (0 = MIN_MATCH) */ | |
113 | ||
114 | local int base_dist[D_CODES]; | |
115 | /* First normalized distance for each code (0 = distance of 1) */ | |
116 | ||
117 | #else | |
118 | # include "trees.h" | |
119 | #endif /* GEN_TREES_H */ | |
120 | ||
121 | struct static_tree_desc_s { | |
122 | const ct_data *static_tree; /* static tree or NULL */ | |
123 | const intf *extra_bits; /* extra bits for each code or NULL */ | |
124 | int extra_base; /* base index for extra_bits */ | |
125 | int elems; /* max number of elements in the tree */ | |
126 | int max_length; /* max bit length for the codes */ | |
127 | }; | |
128 | ||
129 | local static_tree_desc static_l_desc = | |
130 | {static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS}; | |
131 | ||
132 | local static_tree_desc static_d_desc = | |
133 | {static_dtree, extra_dbits, 0, D_CODES, MAX_BITS}; | |
134 | ||
135 | local static_tree_desc static_bl_desc = | |
136 | {(const ct_data *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS}; | |
137 | ||
138 | /* =========================================================================== | |
139 | * Local (static) routines in this file. | |
140 | */ | |
141 | ||
142 | local void tr_static_init OF((void)); | |
143 | local void init_block OF((deflate_state *s)); | |
144 | local void pqdownheap OF((deflate_state *s, ct_data *tree, int k)); | |
145 | local void gen_bitlen OF((deflate_state *s, tree_desc *desc)); | |
146 | local void gen_codes OF((ct_data *tree, int max_code, ushf *bl_count)); | |
147 | local void build_tree OF((deflate_state *s, tree_desc *desc)); | |
148 | local void scan_tree OF((deflate_state *s, ct_data *tree, int max_code)); | |
149 | local void send_tree OF((deflate_state *s, ct_data *tree, int max_code)); | |
150 | local int build_bl_tree OF((deflate_state *s)); | |
151 | local void send_all_trees OF((deflate_state *s, int lcodes, int dcodes, | |
152 | int blcodes)); | |
153 | local void compress_block OF((deflate_state *s, ct_data *ltree, | |
154 | ct_data *dtree)); | |
155 | local void set_data_type OF((deflate_state *s)); | |
156 | local unsigned bi_reverse OF((unsigned value, int length)); | |
157 | local void bi_windup OF((deflate_state *s)); | |
158 | local void bi_flush OF((deflate_state *s)); | |
159 | local void copy_block OF((deflate_state *s, charf *buf, unsigned len, | |
160 | int header)); | |
161 | ||
162 | #ifdef GEN_TREES_H | |
163 | local void gen_trees_header OF((void)); | |
164 | #endif | |
165 | ||
166 | #ifndef __WXDEBUG__ | |
167 | # define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len) | |
168 | /* Send a code of the given tree. c and tree must not have side effects */ | |
169 | ||
170 | #else /* __WXDEBUG__ */ | |
171 | # define send_code(s, c, tree) \ | |
172 | { if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \ | |
173 | send_bits(s, tree[c].Code, tree[c].Len); } | |
174 | #endif | |
175 | ||
176 | /* =========================================================================== | |
177 | * Output a short LSB first on the stream. | |
178 | * IN assertion: there is enough room in pendingBuf. | |
179 | */ | |
180 | #define put_short(s, w) { \ | |
181 | put_byte(s, (uch)((w) & 0xff)); \ | |
182 | put_byte(s, (uch)((ush)(w) >> 8)); \ | |
183 | } | |
184 | ||
185 | /* =========================================================================== | |
186 | * Send a value on a given number of bits. | |
187 | * IN assertion: length <= 16 and value fits in length bits. | |
188 | */ | |
189 | #ifdef __WXDEBUG__ | |
190 | local void send_bits OF((deflate_state *s, int value, int length)); | |
191 | ||
192 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ | |
193 | local void send_bits(deflate_state* s, int value, int length) | |
194 | #else | |
195 | local void send_bits(s, value, length) | |
196 | deflate_state *s; | |
197 | int value; /* value to send */ | |
198 | int length; /* number of bits */ | |
199 | #endif | |
200 | { | |
201 | Tracevv((stderr," l %2d v %4x ", length, value)); | |
202 | Assert(length > 0 && length <= 15, "invalid length"); | |
203 | s->bits_sent += (ulg)length; | |
204 | ||
205 | /* If not enough room in bi_buf, use (valid) bits from bi_buf and | |
206 | * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid)) | |
207 | * unused bits in value. | |
208 | */ | |
209 | if (s->bi_valid > (int)Buf_size - length) { | |
210 | s->bi_buf |= (value << s->bi_valid); | |
211 | put_short(s, s->bi_buf); | |
212 | s->bi_buf = (ush)value >> (Buf_size - s->bi_valid); | |
213 | s->bi_valid += length - Buf_size; | |
214 | } else { | |
215 | s->bi_buf |= value << s->bi_valid; | |
216 | s->bi_valid += length; | |
217 | } | |
218 | } | |
219 | #else /* !__WXDEBUG__ */ | |
220 | ||
221 | #define send_bits(s, value, length) \ | |
222 | { int len = length;\ | |
223 | if (s->bi_valid > (int)Buf_size - len) {\ | |
224 | int val = value;\ | |
225 | s->bi_buf |= (val << s->bi_valid);\ | |
226 | put_short(s, s->bi_buf);\ | |
227 | s->bi_buf = (ush)val >> (Buf_size - s->bi_valid);\ | |
228 | s->bi_valid += len - Buf_size;\ | |
229 | } else {\ | |
230 | s->bi_buf |= (value) << s->bi_valid;\ | |
231 | s->bi_valid += len;\ | |
232 | }\ | |
233 | } | |
234 | #endif /* __WXDEBUG__ */ | |
235 | ||
236 | ||
237 | #define MAX(a,b) (a >= b ? a : b) | |
238 | /* the arguments must not have side effects */ | |
239 | ||
240 | /* =========================================================================== | |
241 | * Initialize the various 'constant' tables. | |
242 | */ | |
243 | local void tr_static_init() | |
244 | { | |
245 | #if defined(GEN_TREES_H) || !defined(STDC) | |
246 | static int static_init_done = 0; | |
247 | int n; /* iterates over tree elements */ | |
248 | int bits; /* bit counter */ | |
249 | int length; /* length value */ | |
250 | int code; /* code value */ | |
251 | int dist; /* distance index */ | |
252 | ush bl_count[MAX_BITS+1]; | |
253 | /* number of codes at each bit length for an optimal tree */ | |
254 | ||
255 | if (static_init_done) return; | |
256 | ||
257 | /* For some embedded targets, global variables are not initialized: */ | |
258 | static_l_desc.static_tree = static_ltree; | |
259 | static_l_desc.extra_bits = extra_lbits; | |
260 | static_d_desc.static_tree = static_dtree; | |
261 | static_d_desc.extra_bits = extra_dbits; | |
262 | static_bl_desc.extra_bits = extra_blbits; | |
263 | ||
264 | /* Initialize the mapping length (0..255) -> length code (0..28) */ | |
265 | length = 0; | |
266 | for (code = 0; code < LENGTH_CODES-1; code++) { | |
267 | base_length[code] = length; | |
268 | for (n = 0; n < (1<<extra_lbits[code]); n++) { | |
269 | _length_code[length++] = (uch)code; | |
270 | } | |
271 | } | |
272 | Assert (length == 256, "tr_static_init: length != 256"); | |
273 | /* Note that the length 255 (match length 258) can be represented | |
274 | * in two different ways: code 284 + 5 bits or code 285, so we | |
275 | * overwrite length_code[255] to use the best encoding: | |
276 | */ | |
277 | _length_code[length-1] = (uch)code; | |
278 | ||
279 | /* Initialize the mapping dist (0..32K) -> dist code (0..29) */ | |
280 | dist = 0; | |
281 | for (code = 0 ; code < 16; code++) { | |
282 | base_dist[code] = dist; | |
283 | for (n = 0; n < (1<<extra_dbits[code]); n++) { | |
284 | _dist_code[dist++] = (uch)code; | |
285 | } | |
286 | } | |
287 | Assert (dist == 256, "tr_static_init: dist != 256"); | |
288 | dist >>= 7; /* from now on, all distances are divided by 128 */ | |
289 | for ( ; code < D_CODES; code++) { | |
290 | base_dist[code] = dist << 7; | |
291 | for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) { | |
292 | _dist_code[256 + dist++] = (uch)code; | |
293 | } | |
294 | } | |
295 | Assert (dist == 256, "tr_static_init: 256+dist != 512"); | |
296 | ||
297 | /* Construct the codes of the static literal tree */ | |
298 | for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0; | |
299 | n = 0; | |
300 | while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++; | |
301 | while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++; | |
302 | while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++; | |
303 | while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++; | |
304 | /* Codes 286 and 287 do not exist, but we must include them in the | |
305 | * tree construction to get a canonical Huffman tree (longest code | |
306 | * all ones) | |
307 | */ | |
308 | gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count); | |
309 | ||
310 | /* The static distance tree is trivial: */ | |
311 | for (n = 0; n < D_CODES; n++) { | |
312 | static_dtree[n].Len = 5; | |
313 | static_dtree[n].Code = bi_reverse((unsigned)n, 5); | |
314 | } | |
315 | static_init_done = 1; | |
316 | ||
317 | # ifdef GEN_TREES_H | |
318 | gen_trees_header(); | |
319 | # endif | |
320 | #endif /* defined(GEN_TREES_H) || !defined(STDC) */ | |
321 | } | |
322 | ||
323 | /* =========================================================================== | |
324 | * Genererate the file trees.h describing the static trees. | |
325 | */ | |
326 | #ifdef GEN_TREES_H | |
327 | # ifndef __WXDEBUG__ | |
328 | # include <stdio.h> | |
329 | # endif | |
330 | ||
331 | # define SEPARATOR(i, last, width) \ | |
332 | ((i) == (last)? "\n};\n\n" : \ | |
333 | ((i) % (width) == (width)-1 ? ",\n" : ", ")) | |
334 | ||
335 | void gen_trees_header() | |
336 | { | |
337 | FILE *header = fopen("trees.h", "w"); | |
338 | int i; | |
339 | ||
340 | Assert (header != NULL, "Can't open trees.h"); | |
341 | fprintf(header, | |
342 | "/* header created automatically with -DGEN_TREES_H */\n\n"); | |
343 | ||
344 | fprintf(header, "local const ct_data static_ltree[L_CODES+2] = {\n"); | |
345 | for (i = 0; i < L_CODES+2; i++) { | |
346 | fprintf(header, "{{%3u},{%3u}}%s", static_ltree[i].Code, | |
347 | static_ltree[i].Len, SEPARATOR(i, L_CODES+1, 5)); | |
348 | } | |
349 | ||
350 | fprintf(header, "local const ct_data static_dtree[D_CODES] = {\n"); | |
351 | for (i = 0; i < D_CODES; i++) { | |
352 | fprintf(header, "{{%2u},{%2u}}%s", static_dtree[i].Code, | |
353 | static_dtree[i].Len, SEPARATOR(i, D_CODES-1, 5)); | |
354 | } | |
355 | ||
356 | fprintf(header, "const uch _dist_code[DIST_CODE_LEN] = {\n"); | |
357 | for (i = 0; i < DIST_CODE_LEN; i++) { | |
358 | fprintf(header, "%2u%s", _dist_code[i], | |
359 | SEPARATOR(i, DIST_CODE_LEN-1, 20)); | |
360 | } | |
361 | ||
362 | fprintf(header, "const uch _length_code[MAX_MATCH-MIN_MATCH+1]= {\n"); | |
363 | for (i = 0; i < MAX_MATCH-MIN_MATCH+1; i++) { | |
364 | fprintf(header, "%2u%s", _length_code[i], | |
365 | SEPARATOR(i, MAX_MATCH-MIN_MATCH, 20)); | |
366 | } | |
367 | ||
368 | fprintf(header, "local const int base_length[LENGTH_CODES] = {\n"); | |
369 | for (i = 0; i < LENGTH_CODES; i++) { | |
370 | fprintf(header, "%1u%s", base_length[i], | |
371 | SEPARATOR(i, LENGTH_CODES-1, 20)); | |
372 | } | |
373 | ||
374 | fprintf(header, "local const int base_dist[D_CODES] = {\n"); | |
375 | for (i = 0; i < D_CODES; i++) { | |
376 | fprintf(header, "%5u%s", base_dist[i], | |
377 | SEPARATOR(i, D_CODES-1, 10)); | |
378 | } | |
379 | ||
380 | fclose(header); | |
381 | } | |
382 | #endif /* GEN_TREES_H */ | |
383 | ||
384 | /* =========================================================================== | |
385 | * Initialize the tree data structures for a new zlib stream. | |
386 | */ | |
387 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ | |
388 | void _tr_init(deflate_state* s) | |
389 | #else | |
390 | void _tr_init(s) | |
391 | deflate_state *s; | |
392 | #endif | |
393 | { | |
394 | tr_static_init(); | |
395 | ||
396 | s->l_desc.dyn_tree = s->dyn_ltree; | |
397 | s->l_desc.stat_desc = &static_l_desc; | |
398 | ||
399 | s->d_desc.dyn_tree = s->dyn_dtree; | |
400 | s->d_desc.stat_desc = &static_d_desc; | |
401 | ||
402 | s->bl_desc.dyn_tree = s->bl_tree; | |
403 | s->bl_desc.stat_desc = &static_bl_desc; | |
404 | ||
405 | s->bi_buf = 0; | |
406 | s->bi_valid = 0; | |
407 | s->last_eob_len = 8; /* enough lookahead for inflate */ | |
408 | #ifdef __WXDEBUG__ | |
409 | s->compressed_len = 0L; | |
410 | s->bits_sent = 0L; | |
411 | #endif | |
412 | ||
413 | /* Initialize the first block of the first file: */ | |
414 | init_block(s); | |
415 | } | |
416 | ||
417 | /* =========================================================================== | |
418 | * Initialize a new block. | |
419 | */ | |
420 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ | |
421 | local void init_block(deflate_state* s) | |
422 | #else | |
423 | local void init_block(s) | |
424 | deflate_state *s; | |
425 | #endif | |
426 | { | |
427 | int n; /* iterates over tree elements */ | |
428 | ||
429 | /* Initialize the trees. */ | |
430 | for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0; | |
431 | for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0; | |
432 | for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0; | |
433 | ||
434 | s->dyn_ltree[END_BLOCK].Freq = 1; | |
435 | s->opt_len = s->static_len = 0L; | |
436 | s->last_lit = s->matches = 0; | |
437 | } | |
438 | ||
439 | #define SMALLEST 1 | |
440 | /* Index within the heap array of least frequent node in the Huffman tree */ | |
441 | ||
442 | ||
443 | /* =========================================================================== | |
444 | * Remove the smallest element from the heap and recreate the heap with | |
445 | * one less element. Updates heap and heap_len. | |
446 | */ | |
447 | #define pqremove(s, tree, top) \ | |
448 | {\ | |
449 | top = s->heap[SMALLEST]; \ | |
450 | s->heap[SMALLEST] = s->heap[s->heap_len--]; \ | |
451 | pqdownheap(s, tree, SMALLEST); \ | |
452 | } | |
453 | ||
454 | /* =========================================================================== | |
455 | * Compares to subtrees, using the tree depth as tie breaker when | |
456 | * the subtrees have equal frequency. This minimizes the worst case length. | |
457 | */ | |
458 | #define smaller(tree, n, m, depth) \ | |
459 | (tree[n].Freq < tree[m].Freq || \ | |
460 | (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m])) | |
461 | ||
462 | /* =========================================================================== | |
463 | * Restore the heap property by moving down the tree starting at node k, | |
464 | * exchanging a node with the smallest of its two sons if necessary, stopping | |
465 | * when the heap property is re-established (each father smaller than its | |
466 | * two sons). | |
467 | */ | |
468 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ | |
469 | local void pqdownheap(deflate_state* s, ct_data* tree, int k) | |
470 | #else | |
471 | local void pqdownheap(s, tree, k) | |
472 | deflate_state *s; | |
473 | ct_data *tree; /* the tree to restore */ | |
474 | int k; /* node to move down */ | |
475 | #endif | |
476 | { | |
477 | int v = s->heap[k]; | |
478 | int j = k << 1; /* left son of k */ | |
479 | while (j <= s->heap_len) { | |
480 | /* Set j to the smallest of the two sons: */ | |
481 | if (j < s->heap_len && | |
482 | smaller(tree, s->heap[j+1], s->heap[j], s->depth)) { | |
483 | j++; | |
484 | } | |
485 | /* Exit if v is smaller than both sons */ | |
486 | if (smaller(tree, v, s->heap[j], s->depth)) break; | |
487 | ||
488 | /* Exchange v with the smallest son */ | |
489 | s->heap[k] = s->heap[j]; k = j; | |
490 | ||
491 | /* And continue down the tree, setting j to the left son of k */ | |
492 | j <<= 1; | |
493 | } | |
494 | s->heap[k] = v; | |
495 | } | |
496 | ||
497 | /* =========================================================================== | |
498 | * Compute the optimal bit lengths for a tree and update the total bit length | |
499 | * for the current block. | |
500 | * IN assertion: the fields freq and dad are set, heap[heap_max] and | |
501 | * above are the tree nodes sorted by increasing frequency. | |
502 | * OUT assertions: the field len is set to the optimal bit length, the | |
503 | * array bl_count contains the frequencies for each bit length. | |
504 | * The length opt_len is updated; static_len is also updated if stree is | |
505 | * not null. | |
506 | */ | |
507 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ | |
508 | local void gen_bitlen(deflate_state* s, tree_desc* desc) | |
509 | #else | |
510 | local void gen_bitlen(s, desc) | |
511 | deflate_state *s; | |
512 | tree_desc *desc; /* the tree descriptor */ | |
513 | #endif | |
514 | { | |
515 | ct_data *tree = desc->dyn_tree; | |
516 | int max_code = desc->max_code; | |
517 | const ct_data *stree = desc->stat_desc->static_tree; | |
518 | const intf *extra = desc->stat_desc->extra_bits; | |
519 | int base = desc->stat_desc->extra_base; | |
520 | int max_length = desc->stat_desc->max_length; | |
521 | int h; /* heap index */ | |
522 | int n, m; /* iterate over the tree elements */ | |
523 | int bits; /* bit length */ | |
524 | int xbits; /* extra bits */ | |
525 | ush f; /* frequency */ | |
526 | int overflow = 0; /* number of elements with bit length too large */ | |
527 | ||
528 | for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0; | |
529 | ||
530 | /* In a first pass, compute the optimal bit lengths (which may | |
531 | * overflow in the case of the bit length tree). | |
532 | */ | |
533 | tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */ | |
534 | ||
535 | for (h = s->heap_max+1; h < HEAP_SIZE; h++) { | |
536 | n = s->heap[h]; | |
537 | bits = tree[tree[n].Dad].Len + 1; | |
538 | if (bits > max_length) bits = max_length, overflow++; | |
539 | tree[n].Len = (ush)bits; | |
540 | /* We overwrite tree[n].Dad which is no longer needed */ | |
541 | ||
542 | if (n > max_code) continue; /* not a leaf node */ | |
543 | ||
544 | s->bl_count[bits]++; | |
545 | xbits = 0; | |
546 | if (n >= base) xbits = extra[n-base]; | |
547 | f = tree[n].Freq; | |
548 | s->opt_len += (ulg)f * (bits + xbits); | |
549 | if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits); | |
550 | } | |
551 | if (overflow == 0) return; | |
552 | ||
553 | Trace((stderr,"\nbit length overflow\n")); | |
554 | /* This happens for example on obj2 and pic of the Calgary corpus */ | |
555 | ||
556 | /* Find the first bit length which could increase: */ | |
557 | do { | |
558 | bits = max_length-1; | |
559 | while (s->bl_count[bits] == 0) bits--; | |
560 | s->bl_count[bits]--; /* move one leaf down the tree */ | |
561 | s->bl_count[bits+1] += 2; /* move one overflow item as its brother */ | |
562 | s->bl_count[max_length]--; | |
563 | /* The brother of the overflow item also moves one step up, | |
564 | * but this does not affect bl_count[max_length] | |
565 | */ | |
566 | overflow -= 2; | |
567 | } while (overflow > 0); | |
568 | ||
569 | /* Now recompute all bit lengths, scanning in increasing frequency. | |
570 | * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all | |
571 | * lengths instead of fixing only the wrong ones. This idea is taken | |
572 | * from 'ar' written by Haruhiko Okumura.) | |
573 | */ | |
574 | for (bits = max_length; bits != 0; bits--) { | |
575 | n = s->bl_count[bits]; | |
576 | while (n != 0) { | |
577 | m = s->heap[--h]; | |
578 | if (m > max_code) continue; | |
579 | if (tree[m].Len != (unsigned) bits) { | |
580 | Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits)); | |
581 | s->opt_len += ((long)bits - (long)tree[m].Len) | |
582 | *(long)tree[m].Freq; | |
583 | tree[m].Len = (ush)bits; | |
584 | } | |
585 | n--; | |
586 | } | |
587 | } | |
588 | } | |
589 | ||
590 | /* =========================================================================== | |
591 | * Generate the codes for a given tree and bit counts (which need not be | |
592 | * optimal). | |
593 | * IN assertion: the array bl_count contains the bit length statistics for | |
594 | * the given tree and the field len is set for all tree elements. | |
595 | * OUT assertion: the field code is set for all tree elements of non | |
596 | * zero code length. | |
597 | */ | |
598 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ | |
599 | local void gen_codes (ct_data* tree, int max_code, ushf* bl_count) | |
600 | #else | |
601 | local void gen_codes (tree, max_code, bl_count) | |
602 | ct_data *tree; /* the tree to decorate */ | |
603 | int max_code; /* largest code with non zero frequency */ | |
604 | ushf *bl_count; /* number of codes at each bit length */ | |
605 | #endif | |
606 | { | |
607 | ush next_code[MAX_BITS+1]; /* next code value for each bit length */ | |
608 | ush code = 0; /* running code value */ | |
609 | int bits; /* bit index */ | |
610 | int n; /* code index */ | |
611 | ||
612 | /* The distribution counts are first used to generate the code values | |
613 | * without bit reversal. | |
614 | */ | |
615 | for (bits = 1; bits <= MAX_BITS; bits++) { | |
616 | next_code[bits] = code = (code + bl_count[bits-1]) << 1; | |
617 | } | |
618 | /* Check that the bit counts in bl_count are consistent. The last code | |
619 | * must be all ones. | |
620 | */ | |
621 | Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1, | |
622 | "inconsistent bit counts"); | |
623 | Tracev((stderr,"\ngen_codes: max_code %d ", max_code)); | |
624 | ||
625 | for (n = 0; n <= max_code; n++) { | |
626 | int len = tree[n].Len; | |
627 | if (len == 0) continue; | |
628 | /* Now reverse the bits */ | |
629 | tree[n].Code = bi_reverse(next_code[len]++, len); | |
630 | ||
631 | Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ", | |
632 | n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1)); | |
633 | } | |
634 | } | |
635 | ||
636 | /* =========================================================================== | |
637 | * Construct one Huffman tree and assigns the code bit strings and lengths. | |
638 | * Update the total bit length for the current block. | |
639 | * IN assertion: the field freq is set for all tree elements. | |
640 | * OUT assertions: the fields len and code are set to the optimal bit length | |
641 | * and corresponding code. The length opt_len is updated; static_len is | |
642 | * also updated if stree is not null. The field max_code is set. | |
643 | */ | |
644 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ | |
645 | local void build_tree(deflate_state* s, tree_desc* desc) | |
646 | #else | |
647 | local void build_tree(s, desc) | |
648 | deflate_state *s; | |
649 | tree_desc *desc; /* the tree descriptor */ | |
650 | #endif | |
651 | { | |
652 | ct_data *tree = desc->dyn_tree; | |
653 | const ct_data *stree = desc->stat_desc->static_tree; | |
654 | int elems = desc->stat_desc->elems; | |
655 | int n, m; /* iterate over heap elements */ | |
656 | int max_code = -1; /* largest code with non zero frequency */ | |
657 | int node; /* new node being created */ | |
658 | ||
659 | /* Construct the initial heap, with least frequent element in | |
660 | * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1]. | |
661 | * heap[0] is not used. | |
662 | */ | |
663 | s->heap_len = 0, s->heap_max = HEAP_SIZE; | |
664 | ||
665 | for (n = 0; n < elems; n++) { | |
666 | if (tree[n].Freq != 0) { | |
667 | s->heap[++(s->heap_len)] = max_code = n; | |
668 | s->depth[n] = 0; | |
669 | } else { | |
670 | tree[n].Len = 0; | |
671 | } | |
672 | } | |
673 | ||
674 | /* The pkzip format requires that at least one distance code exists, | |
675 | * and that at least one bit should be sent even if there is only one | |
676 | * possible code. So to avoid special checks later on we force at least | |
677 | * two codes of non zero frequency. | |
678 | */ | |
679 | while (s->heap_len < 2) { | |
680 | node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0); | |
681 | tree[node].Freq = 1; | |
682 | s->depth[node] = 0; | |
683 | s->opt_len--; if (stree) s->static_len -= stree[node].Len; | |
684 | /* node is 0 or 1 so it does not have extra bits */ | |
685 | } | |
686 | desc->max_code = max_code; | |
687 | ||
688 | /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree, | |
689 | * establish sub-heaps of increasing lengths: | |
690 | */ | |
691 | for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, n); | |
692 | ||
693 | /* Construct the Huffman tree by repeatedly combining the least two | |
694 | * frequent nodes. | |
695 | */ | |
696 | node = elems; /* next internal node of the tree */ | |
697 | do { | |
698 | pqremove(s, tree, n); /* n = node of least frequency */ | |
699 | m = s->heap[SMALLEST]; /* m = node of next least frequency */ | |
700 | ||
701 | s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */ | |
702 | s->heap[--(s->heap_max)] = m; | |
703 | ||
704 | /* Create a new node father of n and m */ | |
705 | tree[node].Freq = tree[n].Freq + tree[m].Freq; | |
706 | s->depth[node] = (uch) (MAX(s->depth[n], s->depth[m]) + 1); | |
707 | tree[n].Dad = tree[m].Dad = (ush)node; | |
708 | #ifdef DUMP_BL_TREE | |
709 | if (tree == s->bl_tree) { | |
710 | fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)", | |
711 | node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq); | |
712 | } | |
713 | #endif | |
714 | /* and insert the new node in the heap */ | |
715 | s->heap[SMALLEST] = node++; | |
716 | pqdownheap(s, tree, SMALLEST); | |
717 | ||
718 | } while (s->heap_len >= 2); | |
719 | ||
720 | s->heap[--(s->heap_max)] = s->heap[SMALLEST]; | |
721 | ||
722 | /* At this point, the fields freq and dad are set. We can now | |
723 | * generate the bit lengths. | |
724 | */ | |
725 | gen_bitlen(s, (tree_desc *)desc); | |
726 | ||
727 | /* The field len is now set, we can generate the bit codes */ | |
728 | gen_codes ((ct_data *)tree, max_code, s->bl_count); | |
729 | } | |
730 | ||
731 | /* =========================================================================== | |
732 | * Scan a literal or distance tree to determine the frequencies of the codes | |
733 | * in the bit length tree. | |
734 | */ | |
735 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ | |
736 | local void scan_tree (deflate_state* s, ct_data* tree, int max_code) | |
737 | #else | |
738 | local void scan_tree (s, tree, max_code) | |
739 | deflate_state *s; | |
740 | ct_data *tree; /* the tree to be scanned */ | |
741 | int max_code; /* and its largest code of non zero frequency */ | |
742 | #endif | |
743 | { | |
744 | int n; /* iterates over all tree elements */ | |
745 | int prevlen = -1; /* last emitted length */ | |
746 | int curlen; /* length of current code */ | |
747 | int nextlen = tree[0].Len; /* length of next code */ | |
748 | int count = 0; /* repeat count of the current code */ | |
749 | int max_count = 7; /* max repeat count */ | |
750 | int min_count = 4; /* min repeat count */ | |
751 | ||
752 | if (nextlen == 0) max_count = 138, min_count = 3; | |
753 | tree[max_code+1].Len = (ush)0xffff; /* guard */ | |
754 | ||
755 | for (n = 0; n <= max_code; n++) { | |
756 | curlen = nextlen; nextlen = tree[n+1].Len; | |
757 | if (++count < max_count && curlen == nextlen) { | |
758 | continue; | |
759 | } else if (count < min_count) { | |
760 | s->bl_tree[curlen].Freq += count; | |
761 | } else if (curlen != 0) { | |
762 | if (curlen != prevlen) s->bl_tree[curlen].Freq++; | |
763 | s->bl_tree[REP_3_6].Freq++; | |
764 | } else if (count <= 10) { | |
765 | s->bl_tree[REPZ_3_10].Freq++; | |
766 | } else { | |
767 | s->bl_tree[REPZ_11_138].Freq++; | |
768 | } | |
769 | count = 0; prevlen = curlen; | |
770 | if (nextlen == 0) { | |
771 | max_count = 138, min_count = 3; | |
772 | } else if (curlen == nextlen) { | |
773 | max_count = 6, min_count = 3; | |
774 | } else { | |
775 | max_count = 7, min_count = 4; | |
776 | } | |
777 | } | |
778 | } | |
779 | ||
780 | /* =========================================================================== | |
781 | * Send a literal or distance tree in compressed form, using the codes in | |
782 | * bl_tree. | |
783 | */ | |
784 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ | |
785 | local void send_tree (deflate_state* s, ct_data* tree, int max_code) | |
786 | #else | |
787 | local void send_tree (s, tree, max_code) | |
788 | deflate_state *s; | |
789 | ct_data *tree; /* the tree to be scanned */ | |
790 | int max_code; /* and its largest code of non zero frequency */ | |
791 | #endif | |
792 | { | |
793 | int n; /* iterates over all tree elements */ | |
794 | int prevlen = -1; /* last emitted length */ | |
795 | int curlen; /* length of current code */ | |
796 | int nextlen = tree[0].Len; /* length of next code */ | |
797 | int count = 0; /* repeat count of the current code */ | |
798 | int max_count = 7; /* max repeat count */ | |
799 | int min_count = 4; /* min repeat count */ | |
800 | ||
801 | /* tree[max_code+1].Len = -1; */ /* guard already set */ | |
802 | if (nextlen == 0) max_count = 138, min_count = 3; | |
803 | ||
804 | for (n = 0; n <= max_code; n++) { | |
805 | curlen = nextlen; nextlen = tree[n+1].Len; | |
806 | if (++count < max_count && curlen == nextlen) { | |
807 | continue; | |
808 | } else if (count < min_count) { | |
809 | do { send_code(s, curlen, s->bl_tree); } while (--count != 0); | |
810 | ||
811 | } else if (curlen != 0) { | |
812 | if (curlen != prevlen) { | |
813 | send_code(s, curlen, s->bl_tree); count--; | |
814 | } | |
815 | Assert(count >= 3 && count <= 6, " 3_6?"); | |
816 | send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2); | |
817 | ||
818 | } else if (count <= 10) { | |
819 | send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3); | |
820 | ||
821 | } else { | |
822 | send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7); | |
823 | } | |
824 | count = 0; prevlen = curlen; | |
825 | if (nextlen == 0) { | |
826 | max_count = 138, min_count = 3; | |
827 | } else if (curlen == nextlen) { | |
828 | max_count = 6, min_count = 3; | |
829 | } else { | |
830 | max_count = 7, min_count = 4; | |
831 | } | |
832 | } | |
833 | } | |
834 | ||
835 | /* =========================================================================== | |
836 | * Construct the Huffman tree for the bit lengths and return the index in | |
837 | * bl_order of the last bit length code to send. | |
838 | */ | |
839 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ | |
840 | local int build_bl_tree( deflate_state* s) | |
841 | #else | |
842 | local int build_bl_tree(s) | |
843 | deflate_state *s; | |
844 | #endif | |
845 | { | |
846 | int max_blindex; /* index of last bit length code of non zero freq */ | |
847 | ||
848 | /* Determine the bit length frequencies for literal and distance trees */ | |
849 | scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code); | |
850 | scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code); | |
851 | ||
852 | /* Build the bit length tree: */ | |
853 | build_tree(s, (tree_desc *)(&(s->bl_desc))); | |
854 | /* opt_len now includes the length of the tree representations, except | |
855 | * the lengths of the bit lengths codes and the 5+5+4 bits for the counts. | |
856 | */ | |
857 | ||
858 | /* Determine the number of bit length codes to send. The pkzip format | |
859 | * requires that at least 4 bit length codes be sent. (appnote.txt says | |
860 | * 3 but the actual value used is 4.) | |
861 | */ | |
862 | for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) { | |
863 | if (s->bl_tree[bl_order[max_blindex]].Len != 0) break; | |
864 | } | |
865 | /* Update opt_len to include the bit length tree and counts */ | |
866 | s->opt_len += 3*(max_blindex+1) + 5+5+4; | |
867 | Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld", | |
868 | s->opt_len, s->static_len)); | |
869 | ||
870 | return max_blindex; | |
871 | } | |
872 | ||
873 | /* =========================================================================== | |
874 | * Send the header for a block using dynamic Huffman trees: the counts, the | |
875 | * lengths of the bit length codes, the literal tree and the distance tree. | |
876 | * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4. | |
877 | */ | |
878 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ | |
879 | local void send_all_trees(deflate_state* s, int lcodes, int dcodes, int blcodes) | |
880 | #else | |
881 | local void send_all_trees(s, lcodes, dcodes, blcodes) | |
882 | deflate_state *s; | |
883 | int lcodes, dcodes, blcodes; /* number of codes for each tree */ | |
884 | #endif | |
885 | { | |
886 | int rank; /* index in bl_order */ | |
887 | ||
888 | Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes"); | |
889 | Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES, | |
890 | "too many codes"); | |
891 | Tracev((stderr, "\nbl counts: ")); | |
892 | send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */ | |
893 | send_bits(s, dcodes-1, 5); | |
894 | send_bits(s, blcodes-4, 4); /* not -3 as stated in appnote.txt */ | |
895 | for (rank = 0; rank < blcodes; rank++) { | |
896 | Tracev((stderr, "\nbl code %2d ", bl_order[rank])); | |
897 | send_bits(s, s->bl_tree[bl_order[rank]].Len, 3); | |
898 | } | |
899 | Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent)); | |
900 | ||
901 | send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */ | |
902 | Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent)); | |
903 | ||
904 | send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */ | |
905 | Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent)); | |
906 | } | |
907 | ||
908 | /* =========================================================================== | |
909 | * Send a stored block | |
910 | */ | |
911 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ | |
912 | void _tr_stored_block(deflate_state* s, charf* buf, ulg stored_len, int eof) | |
913 | #else | |
914 | void _tr_stored_block(s, buf, stored_len, eof) | |
915 | deflate_state *s; | |
916 | charf *buf; /* input block */ | |
917 | ulg stored_len; /* length of input block */ | |
918 | int eof; /* true if this is the last block for a file */ | |
919 | #endif | |
920 | { | |
921 | send_bits(s, (STORED_BLOCK<<1)+eof, 3); /* send block type */ | |
922 | #ifdef __WXDEBUG__ | |
923 | s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L; | |
924 | s->compressed_len += (stored_len + 4) << 3; | |
925 | #endif | |
926 | copy_block(s, buf, (unsigned)stored_len, 1); /* with header */ | |
927 | } | |
928 | ||
929 | /* =========================================================================== | |
930 | * Send one empty static block to give enough lookahead for inflate. | |
931 | * This takes 10 bits, of which 7 may remain in the bit buffer. | |
932 | * The current inflate code requires 9 bits of lookahead. If the | |
933 | * last two codes for the previous block (real code plus EOB) were coded | |
934 | * on 5 bits or less, inflate may have only 5+3 bits of lookahead to decode | |
935 | * the last real code. In this case we send two empty static blocks instead | |
936 | * of one. (There are no problems if the previous block is stored or fixed.) | |
937 | * To simplify the code, we assume the worst case of last real code encoded | |
938 | * on one bit only. | |
939 | */ | |
940 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ | |
941 | void _tr_align(deflate_state* s) | |
942 | #else | |
943 | void _tr_align(s) | |
944 | deflate_state *s; | |
945 | #endif | |
946 | { | |
947 | send_bits(s, STATIC_TREES<<1, 3); | |
948 | send_code(s, END_BLOCK, static_ltree); | |
949 | #ifdef __WXDEBUG__ | |
950 | s->compressed_len += 10L; /* 3 for block type, 7 for EOB */ | |
951 | #endif | |
952 | bi_flush(s); | |
953 | /* Of the 10 bits for the empty block, we have already sent | |
954 | * (10 - bi_valid) bits. The lookahead for the last real code (before | |
955 | * the EOB of the previous block) was thus at least one plus the length | |
956 | * of the EOB plus what we have just sent of the empty static block. | |
957 | */ | |
958 | if (1 + s->last_eob_len + 10 - s->bi_valid < 9) { | |
959 | send_bits(s, STATIC_TREES<<1, 3); | |
960 | send_code(s, END_BLOCK, static_ltree); | |
961 | #ifdef __WXDEBUG__ | |
962 | s->compressed_len += 10L; | |
963 | #endif | |
964 | bi_flush(s); | |
965 | } | |
966 | s->last_eob_len = 7; | |
967 | } | |
968 | ||
969 | /* =========================================================================== | |
970 | * Determine the best encoding for the current block: dynamic trees, static | |
971 | * trees or store, and output the encoded block to the zip file. | |
972 | */ | |
973 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ | |
974 | void _tr_flush_block(deflate_state* s, charf* buf, ulg stored_len, int eof) | |
975 | #else | |
976 | void _tr_flush_block(s, buf, stored_len, eof) | |
977 | deflate_state *s; | |
978 | charf *buf; /* input block, or NULL if too old */ | |
979 | ulg stored_len; /* length of input block */ | |
980 | int eof; /* true if this is the last block for a file */ | |
981 | #endif | |
982 | { | |
983 | ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */ | |
984 | int max_blindex = 0; /* index of last bit length code of non zero freq */ | |
985 | ||
986 | /* Build the Huffman trees unless a stored block is forced */ | |
987 | if (s->level > 0) { | |
988 | ||
989 | /* Check if the file is ascii or binary */ | |
990 | if (s->data_type == Z_UNKNOWN) set_data_type(s); | |
991 | ||
992 | /* Construct the literal and distance trees */ | |
993 | build_tree(s, (tree_desc *)(&(s->l_desc))); | |
994 | Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len, | |
995 | s->static_len)); | |
996 | ||
997 | build_tree(s, (tree_desc *)(&(s->d_desc))); | |
998 | Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len, | |
999 | s->static_len)); | |
1000 | /* At this point, opt_len and static_len are the total bit lengths of | |
1001 | * the compressed block data, excluding the tree representations. | |
1002 | */ | |
1003 | ||
1004 | /* Build the bit length tree for the above two trees, and get the index | |
1005 | * in bl_order of the last bit length code to send. | |
1006 | */ | |
1007 | max_blindex = build_bl_tree(s); | |
1008 | ||
1009 | /* Determine the best encoding. Compute first the block length in bytes*/ | |
1010 | opt_lenb = (s->opt_len+3+7)>>3; | |
1011 | static_lenb = (s->static_len+3+7)>>3; | |
1012 | ||
1013 | Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ", | |
1014 | opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len, | |
1015 | s->last_lit)); | |
1016 | ||
1017 | if (static_lenb <= opt_lenb) opt_lenb = static_lenb; | |
1018 | ||
1019 | } else { | |
1020 | Assert(buf != (char*)0, "lost buf"); | |
1021 | opt_lenb = static_lenb = stored_len + 5; /* force a stored block */ | |
1022 | } | |
1023 | ||
1024 | #ifdef FORCE_STORED | |
1025 | if (buf != (char*)0) { /* force stored block */ | |
1026 | #else | |
1027 | if (stored_len+4 <= opt_lenb && buf != (char*)0) { | |
1028 | /* 4: two words for the lengths */ | |
1029 | #endif | |
1030 | /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE. | |
1031 | * Otherwise we can't have processed more than WSIZE input bytes since | |
1032 | * the last block flush, because compression would have been | |
1033 | * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to | |
1034 | * transform a block into a stored block. | |
1035 | */ | |
1036 | _tr_stored_block(s, buf, stored_len, eof); | |
1037 | ||
1038 | #ifdef FORCE_STATIC | |
1039 | } else if (static_lenb >= 0) { /* force static trees */ | |
1040 | #else | |
1041 | } else if (static_lenb == opt_lenb) { | |
1042 | #endif | |
1043 | send_bits(s, (STATIC_TREES<<1)+eof, 3); | |
1044 | compress_block(s, (ct_data *)static_ltree, (ct_data *)static_dtree); | |
1045 | #ifdef __WXDEBUG__ | |
1046 | s->compressed_len += 3 + s->static_len; | |
1047 | #endif | |
1048 | } else { | |
1049 | send_bits(s, (DYN_TREES<<1)+eof, 3); | |
1050 | send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1, | |
1051 | max_blindex+1); | |
1052 | compress_block(s, (ct_data *)s->dyn_ltree, (ct_data *)s->dyn_dtree); | |
1053 | #ifdef __WXDEBUG__ | |
1054 | s->compressed_len += 3 + s->opt_len; | |
1055 | #endif | |
1056 | } | |
1057 | Assert (s->compressed_len == s->bits_sent, "bad compressed size"); | |
1058 | /* The above check is made mod 2^32, for files larger than 512 MB | |
1059 | * and uLong implemented on 32 bits. | |
1060 | */ | |
1061 | init_block(s); | |
1062 | ||
1063 | if (eof) { | |
1064 | bi_windup(s); | |
1065 | #ifdef __WXDEBUG__ | |
1066 | s->compressed_len += 7; /* align on byte boundary */ | |
1067 | #endif | |
1068 | } | |
1069 | Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3, | |
1070 | s->compressed_len-7*eof)); | |
1071 | } | |
1072 | ||
1073 | /* =========================================================================== | |
1074 | * Save the match info and tally the frequency counts. Return true if | |
1075 | * the current block must be flushed. | |
1076 | */ | |
1077 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ | |
1078 | int _tr_tally (deflate_state* s, unsigned dist, unsigned lc) | |
1079 | #else | |
1080 | int _tr_tally (s, dist, lc) | |
1081 | deflate_state *s; | |
1082 | unsigned dist; /* distance of matched string */ | |
1083 | unsigned lc; /* match length-MIN_MATCH or unmatched char (if dist==0) */ | |
1084 | #endif | |
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 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ | |
1132 | local void compress_block(deflate_state* s, ct_data* ltree, ct_data* dtree) | |
1133 | #else | |
1134 | local void compress_block(s, ltree, dtree) | |
1135 | deflate_state *s; | |
1136 | ct_data *ltree; /* literal tree */ | |
1137 | ct_data *dtree; /* distance tree */ | |
1138 | #endif | |
1139 | { | |
1140 | unsigned dist; /* distance of matched string */ | |
1141 | int lc; /* match length or unmatched char (if dist == 0) */ | |
1142 | unsigned lx = 0; /* running index in l_buf */ | |
1143 | unsigned code; /* the code to send */ | |
1144 | int extra; /* number of extra bits to send */ | |
1145 | ||
1146 | if (s->last_lit != 0) do { | |
1147 | dist = s->d_buf[lx]; | |
1148 | lc = s->l_buf[lx++]; | |
1149 | if (dist == 0) { | |
1150 | send_code(s, lc, ltree); /* send a literal byte */ | |
1151 | Tracecv(isgraph(lc), (stderr," '%c' ", lc)); | |
1152 | } else { | |
1153 | /* Here, lc is the match length - MIN_MATCH */ | |
1154 | code = _length_code[lc]; | |
1155 | send_code(s, code+LITERALS+1, ltree); /* send the length code */ | |
1156 | extra = extra_lbits[code]; | |
1157 | if (extra != 0) { | |
1158 | lc -= base_length[code]; | |
1159 | send_bits(s, lc, extra); /* send the extra length bits */ | |
1160 | } | |
1161 | dist--; /* dist is now the match distance - 1 */ | |
1162 | code = d_code(dist); | |
1163 | Assert (code < D_CODES, "bad d_code"); | |
1164 | ||
1165 | send_code(s, code, dtree); /* send the distance code */ | |
1166 | extra = extra_dbits[code]; | |
1167 | if (extra != 0) { | |
1168 | dist -= base_dist[code]; | |
1169 | send_bits(s, dist, extra); /* send the extra distance bits */ | |
1170 | } | |
1171 | } /* literal or match pair ? */ | |
1172 | ||
1173 | /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */ | |
1174 | Assert(s->pending < s->lit_bufsize + 2*lx, "pendingBuf overflow"); | |
1175 | ||
1176 | } while (lx < s->last_lit); | |
1177 | ||
1178 | send_code(s, END_BLOCK, ltree); | |
1179 | s->last_eob_len = ltree[END_BLOCK].Len; | |
1180 | } | |
1181 | ||
1182 | /* =========================================================================== | |
1183 | * Set the data type to ASCII or BINARY, using a crude approximation: | |
1184 | * binary if more than 20% of the bytes are <= 6 or >= 128, ascii otherwise. | |
1185 | * IN assertion: the fields freq of dyn_ltree are set and the total of all | |
1186 | * frequencies does not exceed 64K (to fit in an int on 16 bit machines). | |
1187 | */ | |
1188 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ | |
1189 | local void set_data_type(deflate_state* s) | |
1190 | #else | |
1191 | local void set_data_type(s) | |
1192 | deflate_state *s; | |
1193 | #endif | |
1194 | { | |
1195 | int n = 0; | |
1196 | unsigned ascii_freq = 0; | |
1197 | unsigned bin_freq = 0; | |
1198 | while (n < 7) bin_freq += s->dyn_ltree[n++].Freq; | |
1199 | while (n < 128) ascii_freq += s->dyn_ltree[n++].Freq; | |
1200 | while (n < LITERALS) bin_freq += s->dyn_ltree[n++].Freq; | |
1201 | s->data_type = (Byte)(bin_freq > (ascii_freq >> 2) ? Z_BINARY : Z_ASCII); | |
1202 | } | |
1203 | ||
1204 | /* =========================================================================== | |
1205 | * Reverse the first len bits of a code, using straightforward code (a faster | |
1206 | * method would use a table) | |
1207 | * IN assertion: 1 <= len <= 15 | |
1208 | */ | |
1209 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ | |
1210 | local unsigned bi_reverse(unsigned code, int len) | |
1211 | #else | |
1212 | local unsigned bi_reverse(code, len) | |
1213 | unsigned code; /* the value to invert */ | |
1214 | int len; /* its bit length */ | |
1215 | #endif | |
1216 | { | |
1217 | register unsigned res = 0; | |
1218 | do { | |
1219 | res |= code & 1; | |
1220 | code >>= 1, res <<= 1; | |
1221 | } while (--len > 0); | |
1222 | return res >> 1; | |
1223 | } | |
1224 | ||
1225 | /* =========================================================================== | |
1226 | * Flush the bit buffer, keeping at most 7 bits in it. | |
1227 | */ | |
1228 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ | |
1229 | local void bi_flush(deflate_state* s) | |
1230 | #else | |
1231 | local void bi_flush(s) | |
1232 | deflate_state *s; | |
1233 | #endif | |
1234 | { | |
1235 | if (s->bi_valid == 16) { | |
1236 | put_short(s, s->bi_buf); | |
1237 | s->bi_buf = 0; | |
1238 | s->bi_valid = 0; | |
1239 | } else if (s->bi_valid >= 8) { | |
1240 | put_byte(s, (Byte)s->bi_buf); | |
1241 | s->bi_buf >>= 8; | |
1242 | s->bi_valid -= 8; | |
1243 | } | |
1244 | } | |
1245 | ||
1246 | /* =========================================================================== | |
1247 | * Flush the bit buffer and align the output on a byte boundary | |
1248 | */ | |
1249 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ | |
1250 | local void bi_windup(deflate_state* s) | |
1251 | #else | |
1252 | local void bi_windup(s) | |
1253 | deflate_state *s; | |
1254 | #endif | |
1255 | { | |
1256 | if (s->bi_valid > 8) { | |
1257 | put_short(s, s->bi_buf); | |
1258 | } else if (s->bi_valid > 0) { | |
1259 | put_byte(s, (Byte)s->bi_buf); | |
1260 | } | |
1261 | s->bi_buf = 0; | |
1262 | s->bi_valid = 0; | |
1263 | #ifdef __WXDEBUG__ | |
1264 | s->bits_sent = (s->bits_sent+7) & ~7; | |
1265 | #endif | |
1266 | } | |
1267 | ||
1268 | /* =========================================================================== | |
1269 | * Copy a stored block, storing first the length and its | |
1270 | * one's complement if requested. | |
1271 | */ | |
1272 | #if defined(__VISAGECPP__) /* Visualage can't handle this antiquated interface */ | |
1273 | local void copy_block(deflate_state* s, charf* buf, unsigned len, int header) | |
1274 | #else | |
1275 | local void copy_block(s, buf, len, header) | |
1276 | deflate_state *s; | |
1277 | charf *buf; /* the input data */ | |
1278 | unsigned len; /* its length */ | |
1279 | int header; /* true if block header must be written */ | |
1280 | #endif | |
1281 | { | |
1282 | bi_windup(s); /* align on byte boundary */ | |
1283 | s->last_eob_len = 8; /* enough lookahead for inflate */ | |
1284 | ||
1285 | if (header) { | |
1286 | put_short(s, (ush)len); | |
1287 | put_short(s, (ush)~len); | |
1288 | #ifdef __WXDEBUG__ | |
1289 | s->bits_sent += 2*16; | |
1290 | #endif | |
1291 | } | |
1292 | #ifdef __WXDEBUG__ | |
1293 | s->bits_sent += (ulg)len<<3; | |
1294 | #endif | |
1295 | while (len--) { | |
1296 | put_byte(s, *buf++); | |
1297 | } | |
1298 | } |