Commit | Line | Data |
---|---|---|
d4286ec4 | 1 | /* trees.c -- output deflated data using Huffman coding |
be59d0ec | 2 | * Copyright (C) 1995-2002 Jean-loup Gailly |
d4286ec4 PM |
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 DEBUG | |
39 | # include <ctype.h> | |
40 | #endif | |
41 | ||
42 | /* =========================================================================== | |
43 | * Constants | |
44 | */ | |
45 | ||
46 | #define MAX_BL_BITS 7 | |
47 | /* Bit length codes must not exceed MAX_BL_BITS bits */ | |
48 | ||
49 | #define END_BLOCK 256 | |
50 | /* end of block literal code */ | |
51 | ||
52 | #define REP_3_6 16 | |
53 | /* repeat previous bit length 3-6 times (2 bits of repeat count) */ | |
54 | ||
55 | #define REPZ_3_10 17 | |
56 | /* repeat a zero length 3-10 times (3 bits of repeat count) */ | |
57 | ||
58 | #define REPZ_11_138 18 | |
59 | /* repeat a zero length 11-138 times (7 bits of repeat count) */ | |
60 | ||
61 | local const int extra_lbits[LENGTH_CODES] /* extra bits for each length code */ | |
62 | = {0,0,0,0,0,0,0,0,1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4,5,5,5,5,0}; | |
63 | ||
64 | local const int extra_dbits[D_CODES] /* extra bits for each distance code */ | |
65 | = {0,0,0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13}; | |
66 | ||
67 | local const int extra_blbits[BL_CODES]/* extra bits for each bit length code */ | |
68 | = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7}; | |
69 | ||
70 | local const uch bl_order[BL_CODES] | |
71 | = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15}; | |
72 | /* The lengths of the bit length codes are sent in order of decreasing | |
73 | * probability, to avoid transmitting the lengths for unused bit length codes. | |
74 | */ | |
75 | ||
76 | #define Buf_size (8 * 2*sizeof(char)) | |
77 | /* Number of bits used within bi_buf. (bi_buf might be implemented on | |
78 | * more than 16 bits on some systems.) | |
79 | */ | |
80 | ||
81 | /* =========================================================================== | |
82 | * Local data. These are initialized only once. | |
83 | */ | |
84 | ||
85 | #define DIST_CODE_LEN 512 /* see definition of array dist_code below */ | |
86 | ||
87 | #if defined(GEN_TREES_H) || !defined(STDC) | |
88 | /* non ANSI compilers may not accept trees.h */ | |
89 | ||
90 | local ct_data static_ltree[L_CODES+2]; | |
91 | /* The static literal tree. Since the bit lengths are imposed, there is no | |
92 | * need for the L_CODES extra codes used during heap construction. However | |
93 | * The codes 286 and 287 are needed to build a canonical tree (see _tr_init | |
94 | * below). | |
95 | */ | |
96 | ||
97 | local ct_data static_dtree[D_CODES]; | |
98 | /* The static distance tree. (Actually a trivial tree since all codes use | |
99 | * 5 bits.) | |
100 | */ | |
101 | ||
102 | uch _dist_code[DIST_CODE_LEN]; | |
103 | /* Distance codes. The first 256 values correspond to the distances | |
104 | * 3 .. 258, the last 256 values correspond to the top 8 bits of | |
105 | * the 15 bit distances. | |
106 | */ | |
107 | ||
108 | uch _length_code[MAX_MATCH-MIN_MATCH+1]; | |
109 | /* length code for each normalized match length (0 == MIN_MATCH) */ | |
110 | ||
111 | local int base_length[LENGTH_CODES]; | |
112 | /* First normalized length for each code (0 = MIN_MATCH) */ | |
113 | ||
114 | local int base_dist[D_CODES]; | |
115 | /* First normalized distance for each code (0 = distance of 1) */ | |
116 | ||
117 | #else | |
118 | # include "trees.h" | |
119 | #endif /* GEN_TREES_H */ | |
120 | ||
121 | struct static_tree_desc_s { | |
122 | const ct_data *static_tree; /* static tree or NULL */ | |
123 | const intf *extra_bits; /* extra bits for each code or NULL */ | |
124 | int extra_base; /* base index for extra_bits */ | |
125 | int elems; /* max number of elements in the tree */ | |
126 | int max_length; /* max bit length for the codes */ | |
127 | }; | |
128 | ||
129 | local static_tree_desc static_l_desc = | |
130 | {static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS}; | |
131 | ||
132 | local static_tree_desc static_d_desc = | |
133 | {static_dtree, extra_dbits, 0, D_CODES, MAX_BITS}; | |
134 | ||
135 | local static_tree_desc static_bl_desc = | |
136 | {(const ct_data *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS}; | |
137 | ||
138 | /* =========================================================================== | |
139 | * Local (static) routines in this file. | |
140 | */ | |
141 | ||
142 | local void tr_static_init OF((void)); | |
143 | local void init_block OF((deflate_state *s)); | |
144 | local void pqdownheap OF((deflate_state *s, ct_data *tree, int k)); | |
145 | local void gen_bitlen OF((deflate_state *s, tree_desc *desc)); | |
146 | local void gen_codes OF((ct_data *tree, int max_code, ushf *bl_count)); | |
147 | local void build_tree OF((deflate_state *s, tree_desc *desc)); | |
148 | local void scan_tree OF((deflate_state *s, ct_data *tree, int max_code)); | |
149 | local void send_tree OF((deflate_state *s, ct_data *tree, int max_code)); | |
150 | local int build_bl_tree OF((deflate_state *s)); | |
151 | local void send_all_trees OF((deflate_state *s, int lcodes, int dcodes, | |
152 | int blcodes)); | |
153 | local void compress_block OF((deflate_state *s, ct_data *ltree, | |
154 | ct_data *dtree)); | |
155 | local void set_data_type OF((deflate_state *s)); | |
156 | local unsigned bi_reverse OF((unsigned value, int length)); | |
157 | local void bi_windup OF((deflate_state *s)); | |
158 | local void bi_flush OF((deflate_state *s)); | |
159 | local void copy_block OF((deflate_state *s, charf *buf, unsigned len, | |
160 | int header)); | |
161 | ||
162 | #ifdef GEN_TREES_H | |
163 | local void gen_trees_header OF((void)); | |
164 | #endif | |
165 | ||
166 | #ifndef DEBUG | |
167 | # define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len) | |
168 | /* Send a code of the given tree. c and tree must not have side effects */ | |
169 | ||
170 | #else /* DEBUG */ | |
171 | # define send_code(s, c, tree) \ | |
172 | { if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \ | |
173 | send_bits(s, tree[c].Code, tree[c].Len); } | |
174 | #endif | |
175 | ||
176 | /* =========================================================================== | |
177 | * Output a short LSB first on the stream. | |
178 | * IN assertion: there is enough room in pendingBuf. | |
179 | */ | |
180 | #define put_short(s, w) { \ | |
181 | put_byte(s, (uch)((w) & 0xff)); \ | |
182 | put_byte(s, (uch)((ush)(w) >> 8)); \ | |
183 | } | |
184 | ||
185 | /* =========================================================================== | |
186 | * Send a value on a given number of bits. | |
187 | * IN assertion: length <= 16 and value fits in length bits. | |
188 | */ | |
189 | #ifdef DEBUG | |
190 | local void send_bits OF((deflate_state *s, int value, int length)); | |
191 | ||
192 | local void send_bits(s, value, length) | |
193 | deflate_state *s; | |
194 | int value; /* value to send */ | |
195 | int length; /* number of bits */ | |
196 | { | |
197 | Tracevv((stderr," l %2d v %4x ", length, value)); | |
198 | Assert(length > 0 && length <= 15, "invalid length"); | |
199 | s->bits_sent += (ulg)length; | |
200 | ||
201 | /* If not enough room in bi_buf, use (valid) bits from bi_buf and | |
202 | * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid)) | |
203 | * unused bits in value. | |
204 | */ | |
205 | if (s->bi_valid > (int)Buf_size - length) { | |
206 | s->bi_buf |= (value << s->bi_valid); | |
207 | put_short(s, s->bi_buf); | |
208 | s->bi_buf = (ush)value >> (Buf_size - s->bi_valid); | |
209 | s->bi_valid += length - Buf_size; | |
210 | } else { | |
211 | s->bi_buf |= value << s->bi_valid; | |
212 | s->bi_valid += length; | |
213 | } | |
214 | } | |
215 | #else /* !DEBUG */ | |
216 | ||
217 | #define send_bits(s, value, length) \ | |
218 | { int len = length;\ | |
219 | if (s->bi_valid > (int)Buf_size - len) {\ | |
220 | int val = value;\ | |
221 | s->bi_buf |= (val << s->bi_valid);\ | |
222 | put_short(s, s->bi_buf);\ | |
223 | s->bi_buf = (ush)val >> (Buf_size - s->bi_valid);\ | |
224 | s->bi_valid += len - Buf_size;\ | |
225 | } else {\ | |
226 | s->bi_buf |= (value) << s->bi_valid;\ | |
227 | s->bi_valid += len;\ | |
228 | }\ | |
229 | } | |
230 | #endif /* DEBUG */ | |
231 | ||
232 | ||
06e27ef7 AT |
233 | #ifndef MAX |
234 | #define MAX(a,b) ((a) >= (b) ? (a) : (b)) | |
235 | #endif | |
d4286ec4 PM |
236 | /* the arguments must not have side effects */ |
237 | ||
238 | /* =========================================================================== | |
239 | * Initialize the various 'constant' tables. | |
240 | */ | |
241 | local void tr_static_init() | |
242 | { | |
243 | #if defined(GEN_TREES_H) || !defined(STDC) | |
244 | static int static_init_done = 0; | |
245 | int n; /* iterates over tree elements */ | |
246 | int bits; /* bit counter */ | |
247 | int length; /* length value */ | |
248 | int code; /* code value */ | |
249 | int dist; /* distance index */ | |
250 | ush bl_count[MAX_BITS+1]; | |
251 | /* number of codes at each bit length for an optimal tree */ | |
252 | ||
253 | if (static_init_done) return; | |
254 | ||
06b91d8e MP |
255 | /* For some embedded targets, global variables are not initialized: */ |
256 | static_l_desc.static_tree = static_ltree; | |
257 | static_l_desc.extra_bits = extra_lbits; | |
258 | static_d_desc.static_tree = static_dtree; | |
259 | static_d_desc.extra_bits = extra_dbits; | |
260 | static_bl_desc.extra_bits = extra_blbits; | |
261 | ||
d4286ec4 PM |
262 | /* Initialize the mapping length (0..255) -> length code (0..28) */ |
263 | length = 0; | |
264 | for (code = 0; code < LENGTH_CODES-1; code++) { | |
265 | base_length[code] = length; | |
266 | for (n = 0; n < (1<<extra_lbits[code]); n++) { | |
267 | _length_code[length++] = (uch)code; | |
268 | } | |
269 | } | |
270 | Assert (length == 256, "tr_static_init: length != 256"); | |
271 | /* Note that the length 255 (match length 258) can be represented | |
272 | * in two different ways: code 284 + 5 bits or code 285, so we | |
273 | * overwrite length_code[255] to use the best encoding: | |
274 | */ | |
275 | _length_code[length-1] = (uch)code; | |
276 | ||
277 | /* Initialize the mapping dist (0..32K) -> dist code (0..29) */ | |
278 | dist = 0; | |
279 | for (code = 0 ; code < 16; code++) { | |
280 | base_dist[code] = dist; | |
281 | for (n = 0; n < (1<<extra_dbits[code]); n++) { | |
282 | _dist_code[dist++] = (uch)code; | |
283 | } | |
284 | } | |
285 | Assert (dist == 256, "tr_static_init: dist != 256"); | |
286 | dist >>= 7; /* from now on, all distances are divided by 128 */ | |
287 | for ( ; code < D_CODES; code++) { | |
288 | base_dist[code] = dist << 7; | |
289 | for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) { | |
290 | _dist_code[256 + dist++] = (uch)code; | |
291 | } | |
292 | } | |
293 | Assert (dist == 256, "tr_static_init: 256+dist != 512"); | |
294 | ||
295 | /* Construct the codes of the static literal tree */ | |
296 | for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0; | |
297 | n = 0; | |
298 | while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++; | |
299 | while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++; | |
300 | while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++; | |
301 | while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++; | |
302 | /* Codes 286 and 287 do not exist, but we must include them in the | |
303 | * tree construction to get a canonical Huffman tree (longest code | |
304 | * all ones) | |
305 | */ | |
306 | gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count); | |
307 | ||
308 | /* The static distance tree is trivial: */ | |
309 | for (n = 0; n < D_CODES; n++) { | |
310 | static_dtree[n].Len = 5; | |
311 | static_dtree[n].Code = bi_reverse((unsigned)n, 5); | |
312 | } | |
313 | static_init_done = 1; | |
314 | ||
315 | # ifdef GEN_TREES_H | |
316 | gen_trees_header(); | |
317 | # endif | |
318 | #endif /* defined(GEN_TREES_H) || !defined(STDC) */ | |
319 | } | |
320 | ||
321 | /* =========================================================================== | |
322 | * Genererate the file trees.h describing the static trees. | |
323 | */ | |
324 | #ifdef GEN_TREES_H | |
325 | # ifndef DEBUG | |
326 | # include <stdio.h> | |
327 | # endif | |
328 | ||
329 | # define SEPARATOR(i, last, width) \ | |
330 | ((i) == (last)? "\n};\n\n" : \ | |
331 | ((i) % (width) == (width)-1 ? ",\n" : ", ")) | |
332 | ||
333 | void gen_trees_header() | |
334 | { | |
335 | FILE *header = fopen("trees.h", "w"); | |
336 | int i; | |
337 | ||
338 | Assert (header != NULL, "Can't open trees.h"); | |
339 | fprintf(header, | |
340 | "/* header created automatically with -DGEN_TREES_H */\n\n"); | |
341 | ||
342 | fprintf(header, "local const ct_data static_ltree[L_CODES+2] = {\n"); | |
343 | for (i = 0; i < L_CODES+2; i++) { | |
344 | fprintf(header, "{{%3u},{%3u}}%s", static_ltree[i].Code, | |
345 | static_ltree[i].Len, SEPARATOR(i, L_CODES+1, 5)); | |
346 | } | |
347 | ||
348 | fprintf(header, "local const ct_data static_dtree[D_CODES] = {\n"); | |
349 | for (i = 0; i < D_CODES; i++) { | |
350 | fprintf(header, "{{%2u},{%2u}}%s", static_dtree[i].Code, | |
351 | static_dtree[i].Len, SEPARATOR(i, D_CODES-1, 5)); | |
352 | } | |
353 | ||
354 | fprintf(header, "const uch _dist_code[DIST_CODE_LEN] = {\n"); | |
355 | for (i = 0; i < DIST_CODE_LEN; i++) { | |
356 | fprintf(header, "%2u%s", _dist_code[i], | |
357 | SEPARATOR(i, DIST_CODE_LEN-1, 20)); | |
358 | } | |
359 | ||
360 | fprintf(header, "const uch _length_code[MAX_MATCH-MIN_MATCH+1]= {\n"); | |
361 | for (i = 0; i < MAX_MATCH-MIN_MATCH+1; i++) { | |
362 | fprintf(header, "%2u%s", _length_code[i], | |
363 | SEPARATOR(i, MAX_MATCH-MIN_MATCH, 20)); | |
364 | } | |
365 | ||
366 | fprintf(header, "local const int base_length[LENGTH_CODES] = {\n"); | |
367 | for (i = 0; i < LENGTH_CODES; i++) { | |
368 | fprintf(header, "%1u%s", base_length[i], | |
369 | SEPARATOR(i, LENGTH_CODES-1, 20)); | |
370 | } | |
371 | ||
372 | fprintf(header, "local const int base_dist[D_CODES] = {\n"); | |
373 | for (i = 0; i < D_CODES; i++) { | |
374 | fprintf(header, "%5u%s", base_dist[i], | |
375 | SEPARATOR(i, D_CODES-1, 10)); | |
376 | } | |
377 | ||
378 | fclose(header); | |
379 | } | |
380 | #endif /* GEN_TREES_H */ | |
381 | ||
382 | /* =========================================================================== | |
383 | * Initialize the tree data structures for a new zlib stream. | |
384 | */ | |
385 | void _tr_init(s) | |
386 | deflate_state *s; | |
387 | { | |
388 | tr_static_init(); | |
389 | ||
d4286ec4 PM |
390 | s->l_desc.dyn_tree = s->dyn_ltree; |
391 | s->l_desc.stat_desc = &static_l_desc; | |
392 | ||
393 | s->d_desc.dyn_tree = s->dyn_dtree; | |
394 | s->d_desc.stat_desc = &static_d_desc; | |
395 | ||
396 | s->bl_desc.dyn_tree = s->bl_tree; | |
397 | s->bl_desc.stat_desc = &static_bl_desc; | |
398 | ||
399 | s->bi_buf = 0; | |
400 | s->bi_valid = 0; | |
401 | s->last_eob_len = 8; /* enough lookahead for inflate */ | |
402 | #ifdef DEBUG | |
06b91d8e | 403 | s->compressed_len = 0L; |
d4286ec4 PM |
404 | s->bits_sent = 0L; |
405 | #endif | |
406 | ||
407 | /* Initialize the first block of the first file: */ | |
408 | init_block(s); | |
409 | } | |
410 | ||
411 | /* =========================================================================== | |
412 | * Initialize a new block. | |
413 | */ | |
414 | local void init_block(s) | |
415 | deflate_state *s; | |
416 | { | |
417 | int n; /* iterates over tree elements */ | |
418 | ||
419 | /* Initialize the trees. */ | |
420 | for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0; | |
421 | for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0; | |
422 | for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0; | |
423 | ||
424 | s->dyn_ltree[END_BLOCK].Freq = 1; | |
425 | s->opt_len = s->static_len = 0L; | |
426 | s->last_lit = s->matches = 0; | |
427 | } | |
428 | ||
429 | #define SMALLEST 1 | |
430 | /* Index within the heap array of least frequent node in the Huffman tree */ | |
431 | ||
432 | ||
433 | /* =========================================================================== | |
434 | * Remove the smallest element from the heap and recreate the heap with | |
435 | * one less element. Updates heap and heap_len. | |
436 | */ | |
437 | #define pqremove(s, tree, top) \ | |
438 | {\ | |
439 | top = s->heap[SMALLEST]; \ | |
440 | s->heap[SMALLEST] = s->heap[s->heap_len--]; \ | |
441 | pqdownheap(s, tree, SMALLEST); \ | |
442 | } | |
443 | ||
444 | /* =========================================================================== | |
445 | * Compares to subtrees, using the tree depth as tie breaker when | |
446 | * the subtrees have equal frequency. This minimizes the worst case length. | |
447 | */ | |
448 | #define smaller(tree, n, m, depth) \ | |
449 | (tree[n].Freq < tree[m].Freq || \ | |
450 | (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m])) | |
451 | ||
452 | /* =========================================================================== | |
453 | * Restore the heap property by moving down the tree starting at node k, | |
454 | * exchanging a node with the smallest of its two sons if necessary, stopping | |
455 | * when the heap property is re-established (each father smaller than its | |
456 | * two sons). | |
457 | */ | |
458 | local void pqdownheap(s, tree, k) | |
459 | deflate_state *s; | |
460 | ct_data *tree; /* the tree to restore */ | |
461 | int k; /* node to move down */ | |
462 | { | |
463 | int v = s->heap[k]; | |
464 | int j = k << 1; /* left son of k */ | |
465 | while (j <= s->heap_len) { | |
466 | /* Set j to the smallest of the two sons: */ | |
467 | if (j < s->heap_len && | |
468 | smaller(tree, s->heap[j+1], s->heap[j], s->depth)) { | |
469 | j++; | |
470 | } | |
471 | /* Exit if v is smaller than both sons */ | |
472 | if (smaller(tree, v, s->heap[j], s->depth)) break; | |
473 | ||
474 | /* Exchange v with the smallest son */ | |
475 | s->heap[k] = s->heap[j]; k = j; | |
476 | ||
477 | /* And continue down the tree, setting j to the left son of k */ | |
478 | j <<= 1; | |
479 | } | |
480 | s->heap[k] = v; | |
481 | } | |
482 | ||
483 | /* =========================================================================== | |
484 | * Compute the optimal bit lengths for a tree and update the total bit length | |
485 | * for the current block. | |
486 | * IN assertion: the fields freq and dad are set, heap[heap_max] and | |
487 | * above are the tree nodes sorted by increasing frequency. | |
488 | * OUT assertions: the field len is set to the optimal bit length, the | |
489 | * array bl_count contains the frequencies for each bit length. | |
490 | * The length opt_len is updated; static_len is also updated if stree is | |
491 | * not null. | |
492 | */ | |
493 | local void gen_bitlen(s, desc) | |
494 | deflate_state *s; | |
495 | tree_desc *desc; /* the tree descriptor */ | |
496 | { | |
497 | ct_data *tree = desc->dyn_tree; | |
498 | int max_code = desc->max_code; | |
499 | const ct_data *stree = desc->stat_desc->static_tree; | |
500 | const intf *extra = desc->stat_desc->extra_bits; | |
501 | int base = desc->stat_desc->extra_base; | |
502 | int max_length = desc->stat_desc->max_length; | |
503 | int h; /* heap index */ | |
504 | int n, m; /* iterate over the tree elements */ | |
505 | int bits; /* bit length */ | |
506 | int xbits; /* extra bits */ | |
507 | ush f; /* frequency */ | |
06e27ef7 | 508 | int Overflow = 0; /* number of elements with bit length too large */ |
d4286ec4 PM |
509 | |
510 | for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0; | |
511 | ||
512 | /* In a first pass, compute the optimal bit lengths (which may | |
513 | * overflow in the case of the bit length tree). | |
514 | */ | |
515 | tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */ | |
516 | ||
517 | for (h = s->heap_max+1; h < HEAP_SIZE; h++) { | |
518 | n = s->heap[h]; | |
519 | bits = tree[tree[n].Dad].Len + 1; | |
06e27ef7 | 520 | if (bits > max_length) bits = max_length, Overflow++; |
d4286ec4 PM |
521 | tree[n].Len = (ush)bits; |
522 | /* We overwrite tree[n].Dad which is no longer needed */ | |
523 | ||
524 | if (n > max_code) continue; /* not a leaf node */ | |
525 | ||
526 | s->bl_count[bits]++; | |
527 | xbits = 0; | |
528 | if (n >= base) xbits = extra[n-base]; | |
529 | f = tree[n].Freq; | |
530 | s->opt_len += (ulg)f * (bits + xbits); | |
531 | if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits); | |
532 | } | |
06e27ef7 | 533 | if (Overflow == 0) return; |
d4286ec4 PM |
534 | |
535 | Trace((stderr,"\nbit length overflow\n")); | |
536 | /* This happens for example on obj2 and pic of the Calgary corpus */ | |
537 | ||
538 | /* Find the first bit length which could increase: */ | |
539 | do { | |
540 | bits = max_length-1; | |
541 | while (s->bl_count[bits] == 0) bits--; | |
542 | s->bl_count[bits]--; /* move one leaf down the tree */ | |
543 | s->bl_count[bits+1] += 2; /* move one overflow item as its brother */ | |
544 | s->bl_count[max_length]--; | |
545 | /* The brother of the overflow item also moves one step up, | |
546 | * but this does not affect bl_count[max_length] | |
547 | */ | |
06e27ef7 AT |
548 | Overflow -= 2; |
549 | } while (Overflow > 0); | |
d4286ec4 PM |
550 | |
551 | /* Now recompute all bit lengths, scanning in increasing frequency. | |
552 | * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all | |
553 | * lengths instead of fixing only the wrong ones. This idea is taken | |
554 | * from 'ar' written by Haruhiko Okumura.) | |
555 | */ | |
556 | for (bits = max_length; bits != 0; bits--) { | |
557 | n = s->bl_count[bits]; | |
558 | while (n != 0) { | |
559 | m = s->heap[--h]; | |
560 | if (m > max_code) continue; | |
561 | if (tree[m].Len != (unsigned) bits) { | |
562 | Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits)); | |
563 | s->opt_len += ((long)bits - (long)tree[m].Len) | |
564 | *(long)tree[m].Freq; | |
565 | tree[m].Len = (ush)bits; | |
566 | } | |
567 | n--; | |
568 | } | |
569 | } | |
570 | } | |
571 | ||
572 | /* =========================================================================== | |
573 | * Generate the codes for a given tree and bit counts (which need not be | |
574 | * optimal). | |
575 | * IN assertion: the array bl_count contains the bit length statistics for | |
576 | * the given tree and the field len is set for all tree elements. | |
577 | * OUT assertion: the field code is set for all tree elements of non | |
578 | * zero code length. | |
579 | */ | |
580 | local void gen_codes (tree, max_code, bl_count) | |
581 | ct_data *tree; /* the tree to decorate */ | |
582 | int max_code; /* largest code with non zero frequency */ | |
583 | ushf *bl_count; /* number of codes at each bit length */ | |
584 | { | |
585 | ush next_code[MAX_BITS+1]; /* next code value for each bit length */ | |
586 | ush code = 0; /* running code value */ | |
587 | int bits; /* bit index */ | |
588 | int n; /* code index */ | |
589 | ||
590 | /* The distribution counts are first used to generate the code values | |
591 | * without bit reversal. | |
592 | */ | |
593 | for (bits = 1; bits <= MAX_BITS; bits++) { | |
594 | next_code[bits] = code = (code + bl_count[bits-1]) << 1; | |
595 | } | |
596 | /* Check that the bit counts in bl_count are consistent. The last code | |
597 | * must be all ones. | |
598 | */ | |
599 | Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1, | |
600 | "inconsistent bit counts"); | |
601 | Tracev((stderr,"\ngen_codes: max_code %d ", max_code)); | |
602 | ||
603 | for (n = 0; n <= max_code; n++) { | |
604 | int len = tree[n].Len; | |
605 | if (len == 0) continue; | |
606 | /* Now reverse the bits */ | |
607 | tree[n].Code = bi_reverse(next_code[len]++, len); | |
608 | ||
609 | Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ", | |
610 | n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1)); | |
611 | } | |
612 | } | |
613 | ||
614 | /* =========================================================================== | |
615 | * Construct one Huffman tree and assigns the code bit strings and lengths. | |
616 | * Update the total bit length for the current block. | |
617 | * IN assertion: the field freq is set for all tree elements. | |
618 | * OUT assertions: the fields len and code are set to the optimal bit length | |
619 | * and corresponding code. The length opt_len is updated; static_len is | |
620 | * also updated if stree is not null. The field max_code is set. | |
621 | */ | |
622 | local void build_tree(s, desc) | |
623 | deflate_state *s; | |
624 | tree_desc *desc; /* the tree descriptor */ | |
625 | { | |
626 | ct_data *tree = desc->dyn_tree; | |
627 | const ct_data *stree = desc->stat_desc->static_tree; | |
628 | int elems = desc->stat_desc->elems; | |
629 | int n, m; /* iterate over heap elements */ | |
630 | int max_code = -1; /* largest code with non zero frequency */ | |
631 | int node; /* new node being created */ | |
632 | ||
633 | /* Construct the initial heap, with least frequent element in | |
634 | * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1]. | |
635 | * heap[0] is not used. | |
636 | */ | |
637 | s->heap_len = 0, s->heap_max = HEAP_SIZE; | |
638 | ||
639 | for (n = 0; n < elems; n++) { | |
640 | if (tree[n].Freq != 0) { | |
641 | s->heap[++(s->heap_len)] = max_code = n; | |
642 | s->depth[n] = 0; | |
643 | } else { | |
644 | tree[n].Len = 0; | |
645 | } | |
646 | } | |
647 | ||
648 | /* The pkzip format requires that at least one distance code exists, | |
649 | * and that at least one bit should be sent even if there is only one | |
650 | * possible code. So to avoid special checks later on we force at least | |
651 | * two codes of non zero frequency. | |
652 | */ | |
653 | while (s->heap_len < 2) { | |
654 | node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0); | |
655 | tree[node].Freq = 1; | |
656 | s->depth[node] = 0; | |
657 | s->opt_len--; if (stree) s->static_len -= stree[node].Len; | |
658 | /* node is 0 or 1 so it does not have extra bits */ | |
659 | } | |
660 | desc->max_code = max_code; | |
661 | ||
662 | /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree, | |
663 | * establish sub-heaps of increasing lengths: | |
664 | */ | |
665 | for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, n); | |
666 | ||
667 | /* Construct the Huffman tree by repeatedly combining the least two | |
668 | * frequent nodes. | |
669 | */ | |
670 | node = elems; /* next internal node of the tree */ | |
671 | do { | |
672 | pqremove(s, tree, n); /* n = node of least frequency */ | |
673 | m = s->heap[SMALLEST]; /* m = node of next least frequency */ | |
674 | ||
675 | s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */ | |
676 | s->heap[--(s->heap_max)] = m; | |
677 | ||
678 | /* Create a new node father of n and m */ | |
679 | tree[node].Freq = tree[n].Freq + tree[m].Freq; | |
680 | s->depth[node] = (uch) (MAX(s->depth[n], s->depth[m]) + 1); | |
681 | tree[n].Dad = tree[m].Dad = (ush)node; | |
682 | #ifdef DUMP_BL_TREE | |
683 | if (tree == s->bl_tree) { | |
684 | fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)", | |
685 | node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq); | |
686 | } | |
687 | #endif | |
688 | /* and insert the new node in the heap */ | |
689 | s->heap[SMALLEST] = node++; | |
690 | pqdownheap(s, tree, SMALLEST); | |
691 | ||
692 | } while (s->heap_len >= 2); | |
693 | ||
694 | s->heap[--(s->heap_max)] = s->heap[SMALLEST]; | |
695 | ||
696 | /* At this point, the fields freq and dad are set. We can now | |
697 | * generate the bit lengths. | |
698 | */ | |
699 | gen_bitlen(s, (tree_desc *)desc); | |
700 | ||
701 | /* The field len is now set, we can generate the bit codes */ | |
702 | gen_codes ((ct_data *)tree, max_code, s->bl_count); | |
703 | } | |
704 | ||
705 | /* =========================================================================== | |
706 | * Scan a literal or distance tree to determine the frequencies of the codes | |
707 | * in the bit length tree. | |
708 | */ | |
709 | local void scan_tree (s, tree, max_code) | |
710 | deflate_state *s; | |
711 | ct_data *tree; /* the tree to be scanned */ | |
712 | int max_code; /* and its largest code of non zero frequency */ | |
713 | { | |
714 | int n; /* iterates over all tree elements */ | |
715 | int prevlen = -1; /* last emitted length */ | |
716 | int curlen; /* length of current code */ | |
717 | int nextlen = tree[0].Len; /* length of next code */ | |
718 | int count = 0; /* repeat count of the current code */ | |
719 | int max_count = 7; /* max repeat count */ | |
720 | int min_count = 4; /* min repeat count */ | |
721 | ||
722 | if (nextlen == 0) max_count = 138, min_count = 3; | |
723 | tree[max_code+1].Len = (ush)0xffff; /* guard */ | |
724 | ||
725 | for (n = 0; n <= max_code; n++) { | |
726 | curlen = nextlen; nextlen = tree[n+1].Len; | |
727 | if (++count < max_count && curlen == nextlen) { | |
728 | continue; | |
729 | } else if (count < min_count) { | |
730 | s->bl_tree[curlen].Freq += count; | |
731 | } else if (curlen != 0) { | |
732 | if (curlen != prevlen) s->bl_tree[curlen].Freq++; | |
733 | s->bl_tree[REP_3_6].Freq++; | |
734 | } else if (count <= 10) { | |
735 | s->bl_tree[REPZ_3_10].Freq++; | |
736 | } else { | |
737 | s->bl_tree[REPZ_11_138].Freq++; | |
738 | } | |
739 | count = 0; prevlen = curlen; | |
740 | if (nextlen == 0) { | |
741 | max_count = 138, min_count = 3; | |
742 | } else if (curlen == nextlen) { | |
743 | max_count = 6, min_count = 3; | |
744 | } else { | |
745 | max_count = 7, min_count = 4; | |
746 | } | |
747 | } | |
748 | } | |
749 | ||
750 | /* =========================================================================== | |
751 | * Send a literal or distance tree in compressed form, using the codes in | |
752 | * bl_tree. | |
753 | */ | |
754 | local void send_tree (s, tree, max_code) | |
755 | deflate_state *s; | |
756 | ct_data *tree; /* the tree to be scanned */ | |
757 | int max_code; /* and its largest code of non zero frequency */ | |
758 | { | |
759 | int n; /* iterates over all tree elements */ | |
760 | int prevlen = -1; /* last emitted length */ | |
761 | int curlen; /* length of current code */ | |
762 | int nextlen = tree[0].Len; /* length of next code */ | |
763 | int count = 0; /* repeat count of the current code */ | |
764 | int max_count = 7; /* max repeat count */ | |
765 | int min_count = 4; /* min repeat count */ | |
766 | ||
767 | /* tree[max_code+1].Len = -1; */ /* guard already set */ | |
768 | if (nextlen == 0) max_count = 138, min_count = 3; | |
769 | ||
770 | for (n = 0; n <= max_code; n++) { | |
771 | curlen = nextlen; nextlen = tree[n+1].Len; | |
772 | if (++count < max_count && curlen == nextlen) { | |
773 | continue; | |
774 | } else if (count < min_count) { | |
775 | do { send_code(s, curlen, s->bl_tree); } while (--count != 0); | |
776 | ||
777 | } else if (curlen != 0) { | |
778 | if (curlen != prevlen) { | |
779 | send_code(s, curlen, s->bl_tree); count--; | |
780 | } | |
781 | Assert(count >= 3 && count <= 6, " 3_6?"); | |
782 | send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2); | |
783 | ||
784 | } else if (count <= 10) { | |
785 | send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3); | |
786 | ||
787 | } else { | |
788 | send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7); | |
789 | } | |
790 | count = 0; prevlen = curlen; | |
791 | if (nextlen == 0) { | |
792 | max_count = 138, min_count = 3; | |
793 | } else if (curlen == nextlen) { | |
794 | max_count = 6, min_count = 3; | |
795 | } else { | |
796 | max_count = 7, min_count = 4; | |
797 | } | |
798 | } | |
799 | } | |
800 | ||
801 | /* =========================================================================== | |
802 | * Construct the Huffman tree for the bit lengths and return the index in | |
803 | * bl_order of the last bit length code to send. | |
804 | */ | |
805 | local int build_bl_tree(s) | |
806 | deflate_state *s; | |
807 | { | |
808 | int max_blindex; /* index of last bit length code of non zero freq */ | |
809 | ||
810 | /* Determine the bit length frequencies for literal and distance trees */ | |
811 | scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code); | |
812 | scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code); | |
813 | ||
814 | /* Build the bit length tree: */ | |
815 | build_tree(s, (tree_desc *)(&(s->bl_desc))); | |
816 | /* opt_len now includes the length of the tree representations, except | |
817 | * the lengths of the bit lengths codes and the 5+5+4 bits for the counts. | |
818 | */ | |
819 | ||
820 | /* Determine the number of bit length codes to send. The pkzip format | |
821 | * requires that at least 4 bit length codes be sent. (appnote.txt says | |
822 | * 3 but the actual value used is 4.) | |
823 | */ | |
824 | for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) { | |
825 | if (s->bl_tree[bl_order[max_blindex]].Len != 0) break; | |
826 | } | |
827 | /* Update opt_len to include the bit length tree and counts */ | |
828 | s->opt_len += 3*(max_blindex+1) + 5+5+4; | |
829 | Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld", | |
830 | s->opt_len, s->static_len)); | |
831 | ||
832 | return max_blindex; | |
833 | } | |
834 | ||
835 | /* =========================================================================== | |
836 | * Send the header for a block using dynamic Huffman trees: the counts, the | |
837 | * lengths of the bit length codes, the literal tree and the distance tree. | |
838 | * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4. | |
839 | */ | |
840 | local void send_all_trees(s, lcodes, dcodes, blcodes) | |
841 | deflate_state *s; | |
842 | int lcodes, dcodes, blcodes; /* number of codes for each tree */ | |
843 | { | |
844 | int rank; /* index in bl_order */ | |
845 | ||
846 | Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes"); | |
847 | Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES, | |
848 | "too many codes"); | |
849 | Tracev((stderr, "\nbl counts: ")); | |
850 | send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */ | |
851 | send_bits(s, dcodes-1, 5); | |
852 | send_bits(s, blcodes-4, 4); /* not -3 as stated in appnote.txt */ | |
853 | for (rank = 0; rank < blcodes; rank++) { | |
854 | Tracev((stderr, "\nbl code %2d ", bl_order[rank])); | |
855 | send_bits(s, s->bl_tree[bl_order[rank]].Len, 3); | |
856 | } | |
857 | Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent)); | |
858 | ||
859 | send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */ | |
860 | Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent)); | |
861 | ||
862 | send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */ | |
863 | Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent)); | |
864 | } | |
865 | ||
866 | /* =========================================================================== | |
867 | * Send a stored block | |
868 | */ | |
869 | void _tr_stored_block(s, buf, stored_len, eof) | |
870 | deflate_state *s; | |
871 | charf *buf; /* input block */ | |
872 | ulg stored_len; /* length of input block */ | |
873 | int eof; /* true if this is the last block for a file */ | |
874 | { | |
875 | send_bits(s, (STORED_BLOCK<<1)+eof, 3); /* send block type */ | |
06b91d8e | 876 | #ifdef DEBUG |
d4286ec4 PM |
877 | s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L; |
878 | s->compressed_len += (stored_len + 4) << 3; | |
06b91d8e | 879 | #endif |
d4286ec4 PM |
880 | copy_block(s, buf, (unsigned)stored_len, 1); /* with header */ |
881 | } | |
882 | ||
883 | /* =========================================================================== | |
884 | * Send one empty static block to give enough lookahead for inflate. | |
885 | * This takes 10 bits, of which 7 may remain in the bit buffer. | |
886 | * The current inflate code requires 9 bits of lookahead. If the | |
887 | * last two codes for the previous block (real code plus EOB) were coded | |
888 | * on 5 bits or less, inflate may have only 5+3 bits of lookahead to decode | |
889 | * the last real code. In this case we send two empty static blocks instead | |
890 | * of one. (There are no problems if the previous block is stored or fixed.) | |
891 | * To simplify the code, we assume the worst case of last real code encoded | |
892 | * on one bit only. | |
893 | */ | |
894 | void _tr_align(s) | |
895 | deflate_state *s; | |
896 | { | |
897 | send_bits(s, STATIC_TREES<<1, 3); | |
898 | send_code(s, END_BLOCK, static_ltree); | |
06b91d8e | 899 | #ifdef DEBUG |
d4286ec4 | 900 | s->compressed_len += 10L; /* 3 for block type, 7 for EOB */ |
06b91d8e | 901 | #endif |
d4286ec4 PM |
902 | bi_flush(s); |
903 | /* Of the 10 bits for the empty block, we have already sent | |
904 | * (10 - bi_valid) bits. The lookahead for the last real code (before | |
905 | * the EOB of the previous block) was thus at least one plus the length | |
906 | * of the EOB plus what we have just sent of the empty static block. | |
907 | */ | |
908 | if (1 + s->last_eob_len + 10 - s->bi_valid < 9) { | |
909 | send_bits(s, STATIC_TREES<<1, 3); | |
910 | send_code(s, END_BLOCK, static_ltree); | |
06b91d8e | 911 | #ifdef DEBUG |
d4286ec4 | 912 | s->compressed_len += 10L; |
06b91d8e | 913 | #endif |
d4286ec4 PM |
914 | bi_flush(s); |
915 | } | |
916 | s->last_eob_len = 7; | |
917 | } | |
918 | ||
919 | /* =========================================================================== | |
920 | * Determine the best encoding for the current block: dynamic trees, static | |
06b91d8e | 921 | * trees or store, and output the encoded block to the zip file. |
d4286ec4 | 922 | */ |
06b91d8e | 923 | void _tr_flush_block(s, buf, stored_len, eof) |
d4286ec4 PM |
924 | deflate_state *s; |
925 | charf *buf; /* input block, or NULL if too old */ | |
926 | ulg stored_len; /* length of input block */ | |
927 | int eof; /* true if this is the last block for a file */ | |
928 | { | |
929 | ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */ | |
930 | int max_blindex = 0; /* index of last bit length code of non zero freq */ | |
931 | ||
932 | /* Build the Huffman trees unless a stored block is forced */ | |
933 | if (s->level > 0) { | |
934 | ||
935 | /* Check if the file is ascii or binary */ | |
936 | if (s->data_type == Z_UNKNOWN) set_data_type(s); | |
937 | ||
938 | /* Construct the literal and distance trees */ | |
939 | build_tree(s, (tree_desc *)(&(s->l_desc))); | |
940 | Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len, | |
941 | s->static_len)); | |
942 | ||
943 | build_tree(s, (tree_desc *)(&(s->d_desc))); | |
944 | Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len, | |
945 | s->static_len)); | |
946 | /* At this point, opt_len and static_len are the total bit lengths of | |
947 | * the compressed block data, excluding the tree representations. | |
948 | */ | |
949 | ||
950 | /* Build the bit length tree for the above two trees, and get the index | |
951 | * in bl_order of the last bit length code to send. | |
952 | */ | |
953 | max_blindex = build_bl_tree(s); | |
954 | ||
955 | /* Determine the best encoding. Compute first the block length in bytes*/ | |
956 | opt_lenb = (s->opt_len+3+7)>>3; | |
957 | static_lenb = (s->static_len+3+7)>>3; | |
958 | ||
959 | Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ", | |
960 | opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len, | |
961 | s->last_lit)); | |
962 | ||
963 | if (static_lenb <= opt_lenb) opt_lenb = static_lenb; | |
964 | ||
965 | } else { | |
966 | Assert(buf != (char*)0, "lost buf"); | |
967 | opt_lenb = static_lenb = stored_len + 5; /* force a stored block */ | |
968 | } | |
969 | ||
d4286ec4 PM |
970 | #ifdef FORCE_STORED |
971 | if (buf != (char*)0) { /* force stored block */ | |
972 | #else | |
973 | if (stored_len+4 <= opt_lenb && buf != (char*)0) { | |
974 | /* 4: two words for the lengths */ | |
975 | #endif | |
976 | /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE. | |
977 | * Otherwise we can't have processed more than WSIZE input bytes since | |
978 | * the last block flush, because compression would have been | |
979 | * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to | |
980 | * transform a block into a stored block. | |
981 | */ | |
982 | _tr_stored_block(s, buf, stored_len, eof); | |
983 | ||
984 | #ifdef FORCE_STATIC | |
985 | } else if (static_lenb >= 0) { /* force static trees */ | |
986 | #else | |
987 | } else if (static_lenb == opt_lenb) { | |
988 | #endif | |
989 | send_bits(s, (STATIC_TREES<<1)+eof, 3); | |
990 | compress_block(s, (ct_data *)static_ltree, (ct_data *)static_dtree); | |
06b91d8e | 991 | #ifdef DEBUG |
d4286ec4 | 992 | s->compressed_len += 3 + s->static_len; |
06b91d8e | 993 | #endif |
d4286ec4 PM |
994 | } else { |
995 | send_bits(s, (DYN_TREES<<1)+eof, 3); | |
996 | send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1, | |
997 | max_blindex+1); | |
998 | compress_block(s, (ct_data *)s->dyn_ltree, (ct_data *)s->dyn_dtree); | |
06b91d8e | 999 | #ifdef DEBUG |
d4286ec4 | 1000 | s->compressed_len += 3 + s->opt_len; |
06b91d8e | 1001 | #endif |
d4286ec4 PM |
1002 | } |
1003 | Assert (s->compressed_len == s->bits_sent, "bad compressed size"); | |
06b91d8e MP |
1004 | /* The above check is made mod 2^32, for files larger than 512 MB |
1005 | * and uLong implemented on 32 bits. | |
1006 | */ | |
d4286ec4 PM |
1007 | init_block(s); |
1008 | ||
1009 | if (eof) { | |
1010 | bi_windup(s); | |
06b91d8e | 1011 | #ifdef DEBUG |
d4286ec4 | 1012 | s->compressed_len += 7; /* align on byte boundary */ |
06b91d8e | 1013 | #endif |
d4286ec4 PM |
1014 | } |
1015 | Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3, | |
1016 | s->compressed_len-7*eof)); | |
d4286ec4 PM |
1017 | } |
1018 | ||
1019 | /* =========================================================================== | |
1020 | * Save the match info and tally the frequency counts. Return true if | |
1021 | * the current block must be flushed. | |
1022 | */ | |
1023 | int _tr_tally (s, dist, lc) | |
1024 | deflate_state *s; | |
1025 | unsigned dist; /* distance of matched string */ | |
1026 | unsigned lc; /* match length-MIN_MATCH or unmatched char (if dist==0) */ | |
1027 | { | |
1028 | s->d_buf[s->last_lit] = (ush)dist; | |
1029 | s->l_buf[s->last_lit++] = (uch)lc; | |
1030 | if (dist == 0) { | |
1031 | /* lc is the unmatched char */ | |
1032 | s->dyn_ltree[lc].Freq++; | |
1033 | } else { | |
1034 | s->matches++; | |
1035 | /* Here, lc is the match length - MIN_MATCH */ | |
1036 | dist--; /* dist = match distance - 1 */ | |
1037 | Assert((ush)dist < (ush)MAX_DIST(s) && | |
1038 | (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) && | |
1039 | (ush)d_code(dist) < (ush)D_CODES, "_tr_tally: bad match"); | |
1040 | ||
1041 | s->dyn_ltree[_length_code[lc]+LITERALS+1].Freq++; | |
1042 | s->dyn_dtree[d_code(dist)].Freq++; | |
1043 | } | |
1044 | ||
1045 | #ifdef TRUNCATE_BLOCK | |
1046 | /* Try to guess if it is profitable to stop the current block here */ | |
1047 | if ((s->last_lit & 0x1fff) == 0 && s->level > 2) { | |
1048 | /* Compute an upper bound for the compressed length */ | |
1049 | ulg out_length = (ulg)s->last_lit*8L; | |
1050 | ulg in_length = (ulg)((long)s->strstart - s->block_start); | |
1051 | int dcode; | |
1052 | for (dcode = 0; dcode < D_CODES; dcode++) { | |
1053 | out_length += (ulg)s->dyn_dtree[dcode].Freq * | |
1054 | (5L+extra_dbits[dcode]); | |
1055 | } | |
1056 | out_length >>= 3; | |
1057 | Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ", | |
1058 | s->last_lit, in_length, out_length, | |
1059 | 100L - out_length*100L/in_length)); | |
1060 | if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1; | |
1061 | } | |
1062 | #endif | |
1063 | return (s->last_lit == s->lit_bufsize-1); | |
1064 | /* We avoid equality with lit_bufsize because of wraparound at 64K | |
1065 | * on 16 bit machines and because stored blocks are restricted to | |
1066 | * 64K-1 bytes. | |
1067 | */ | |
1068 | } | |
1069 | ||
1070 | /* =========================================================================== | |
1071 | * Send the block data compressed using the given Huffman trees | |
1072 | */ | |
1073 | local void compress_block(s, ltree, dtree) | |
1074 | deflate_state *s; | |
1075 | ct_data *ltree; /* literal tree */ | |
1076 | ct_data *dtree; /* distance tree */ | |
1077 | { | |
1078 | unsigned dist; /* distance of matched string */ | |
1079 | int lc; /* match length or unmatched char (if dist == 0) */ | |
1080 | unsigned lx = 0; /* running index in l_buf */ | |
1081 | unsigned code; /* the code to send */ | |
1082 | int extra; /* number of extra bits to send */ | |
1083 | ||
1084 | if (s->last_lit != 0) do { | |
1085 | dist = s->d_buf[lx]; | |
1086 | lc = s->l_buf[lx++]; | |
1087 | if (dist == 0) { | |
1088 | send_code(s, lc, ltree); /* send a literal byte */ | |
1089 | Tracecv(isgraph(lc), (stderr," '%c' ", lc)); | |
1090 | } else { | |
1091 | /* Here, lc is the match length - MIN_MATCH */ | |
1092 | code = _length_code[lc]; | |
1093 | send_code(s, code+LITERALS+1, ltree); /* send the length code */ | |
1094 | extra = extra_lbits[code]; | |
1095 | if (extra != 0) { | |
1096 | lc -= base_length[code]; | |
1097 | send_bits(s, lc, extra); /* send the extra length bits */ | |
1098 | } | |
1099 | dist--; /* dist is now the match distance - 1 */ | |
1100 | code = d_code(dist); | |
1101 | Assert (code < D_CODES, "bad d_code"); | |
1102 | ||
1103 | send_code(s, code, dtree); /* send the distance code */ | |
1104 | extra = extra_dbits[code]; | |
1105 | if (extra != 0) { | |
1106 | dist -= base_dist[code]; | |
1107 | send_bits(s, dist, extra); /* send the extra distance bits */ | |
1108 | } | |
1109 | } /* literal or match pair ? */ | |
1110 | ||
1111 | /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */ | |
1112 | Assert(s->pending < s->lit_bufsize + 2*lx, "pendingBuf overflow"); | |
1113 | ||
1114 | } while (lx < s->last_lit); | |
1115 | ||
1116 | send_code(s, END_BLOCK, ltree); | |
1117 | s->last_eob_len = ltree[END_BLOCK].Len; | |
1118 | } | |
1119 | ||
1120 | /* =========================================================================== | |
1121 | * Set the data type to ASCII or BINARY, using a crude approximation: | |
1122 | * binary if more than 20% of the bytes are <= 6 or >= 128, ascii otherwise. | |
1123 | * IN assertion: the fields freq of dyn_ltree are set and the total of all | |
1124 | * frequencies does not exceed 64K (to fit in an int on 16 bit machines). | |
1125 | */ | |
1126 | local void set_data_type(s) | |
1127 | deflate_state *s; | |
1128 | { | |
1129 | int n = 0; | |
1130 | unsigned ascii_freq = 0; | |
1131 | unsigned bin_freq = 0; | |
1132 | while (n < 7) bin_freq += s->dyn_ltree[n++].Freq; | |
1133 | while (n < 128) ascii_freq += s->dyn_ltree[n++].Freq; | |
1134 | while (n < LITERALS) bin_freq += s->dyn_ltree[n++].Freq; | |
1135 | s->data_type = (Byte)(bin_freq > (ascii_freq >> 2) ? Z_BINARY : Z_ASCII); | |
1136 | } | |
1137 | ||
1138 | /* =========================================================================== | |
1139 | * Reverse the first len bits of a code, using straightforward code (a faster | |
1140 | * method would use a table) | |
1141 | * IN assertion: 1 <= len <= 15 | |
1142 | */ | |
1143 | local unsigned bi_reverse(code, len) | |
1144 | unsigned code; /* the value to invert */ | |
1145 | int len; /* its bit length */ | |
1146 | { | |
1147 | register unsigned res = 0; | |
1148 | do { | |
1149 | res |= code & 1; | |
1150 | code >>= 1, res <<= 1; | |
1151 | } while (--len > 0); | |
1152 | return res >> 1; | |
1153 | } | |
1154 | ||
1155 | /* =========================================================================== | |
1156 | * Flush the bit buffer, keeping at most 7 bits in it. | |
1157 | */ | |
1158 | local void bi_flush(s) | |
1159 | deflate_state *s; | |
1160 | { | |
1161 | if (s->bi_valid == 16) { | |
1162 | put_short(s, s->bi_buf); | |
1163 | s->bi_buf = 0; | |
1164 | s->bi_valid = 0; | |
1165 | } else if (s->bi_valid >= 8) { | |
1166 | put_byte(s, (Byte)s->bi_buf); | |
1167 | s->bi_buf >>= 8; | |
1168 | s->bi_valid -= 8; | |
1169 | } | |
1170 | } | |
1171 | ||
1172 | /* =========================================================================== | |
1173 | * Flush the bit buffer and align the output on a byte boundary | |
1174 | */ | |
1175 | local void bi_windup(s) | |
1176 | deflate_state *s; | |
1177 | { | |
1178 | if (s->bi_valid > 8) { | |
1179 | put_short(s, s->bi_buf); | |
1180 | } else if (s->bi_valid > 0) { | |
1181 | put_byte(s, (Byte)s->bi_buf); | |
1182 | } | |
1183 | s->bi_buf = 0; | |
1184 | s->bi_valid = 0; | |
1185 | #ifdef DEBUG | |
1186 | s->bits_sent = (s->bits_sent+7) & ~7; | |
1187 | #endif | |
1188 | } | |
1189 | ||
1190 | /* =========================================================================== | |
1191 | * Copy a stored block, storing first the length and its | |
1192 | * one's complement if requested. | |
1193 | */ | |
1194 | local void copy_block(s, buf, len, header) | |
1195 | deflate_state *s; | |
1196 | charf *buf; /* the input data */ | |
1197 | unsigned len; /* its length */ | |
1198 | int header; /* true if block header must be written */ | |
1199 | { | |
1200 | bi_windup(s); /* align on byte boundary */ | |
1201 | s->last_eob_len = 8; /* enough lookahead for inflate */ | |
1202 | ||
1203 | if (header) { | |
1204 | put_short(s, (ush)len); | |
1205 | put_short(s, (ush)~len); | |
1206 | #ifdef DEBUG | |
1207 | s->bits_sent += 2*16; | |
1208 | #endif | |
1209 | } | |
1210 | #ifdef DEBUG | |
1211 | s->bits_sent += (ulg)len<<3; | |
1212 | #endif | |
1213 | while (len--) { | |
1214 | put_byte(s, *buf++); | |
1215 | } | |
1216 | } |