author | zautrix <zautrix> | 2004-10-19 20:16:14 (UTC) |
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committer | zautrix <zautrix> | 2004-10-19 20:16:14 (UTC) |
commit | eca49bb06a71980ef61d078904573f25890fc7f2 (patch) (unidiff) | |
tree | c5338e3b12430248979a9ac2c1c7e6646ea9ecdf /pwmanager/libcrypt/zlib/trees.c | |
parent | 53cc32b6e7b1f672bf91b2baf2df6c1e8baf3e0a (diff) | |
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Initial revision
Diffstat (limited to 'pwmanager/libcrypt/zlib/trees.c') (more/less context) (ignore whitespace changes)
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diff --git a/pwmanager/libcrypt/zlib/trees.c b/pwmanager/libcrypt/zlib/trees.c new file mode 100644 index 0000000..0a98405 --- a/dev/null +++ b/pwmanager/libcrypt/zlib/trees.c | |||
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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 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 | |||
233 | #define MAX(a,b) (a >= b ? a : b) | ||
234 | /* the arguments must not have side effects */ | ||
235 | |||
236 | /* =========================================================================== | ||
237 | * Initialize the various 'constant' tables. | ||
238 | */ | ||
239 | local void tr_static_init() | ||
240 | { | ||
241 | #if defined(GEN_TREES_H) || !defined(STDC) | ||
242 | static int static_init_done = 0; | ||
243 | int n; /* iterates over tree elements */ | ||
244 | int bits; /* bit counter */ | ||
245 | int length; /* length value */ | ||
246 | int code; /* code value */ | ||
247 | int dist; /* distance index */ | ||
248 | ush bl_count[MAX_BITS+1]; | ||
249 | /* number of codes at each bit length for an optimal tree */ | ||
250 | |||
251 | if (static_init_done) return; | ||
252 | |||
253 | /* For some embedded targets, global variables are not initialized: */ | ||
254 | static_l_desc.static_tree = static_ltree; | ||
255 | static_l_desc.extra_bits = extra_lbits; | ||
256 | static_d_desc.static_tree = static_dtree; | ||
257 | static_d_desc.extra_bits = extra_dbits; | ||
258 | static_bl_desc.extra_bits = extra_blbits; | ||
259 | |||
260 | /* Initialize the mapping length (0..255) -> length code (0..28) */ | ||
261 | length = 0; | ||
262 | for (code = 0; code < LENGTH_CODES-1; code++) { | ||
263 | base_length[code] = length; | ||
264 | for (n = 0; n < (1<<extra_lbits[code]); n++) { | ||
265 | _length_code[length++] = (uch)code; | ||
266 | } | ||
267 | } | ||
268 | Assert (length == 256, "tr_static_init: length != 256"); | ||
269 | /* Note that the length 255 (match length 258) can be represented | ||
270 | * in two different ways: code 284 + 5 bits or code 285, so we | ||
271 | * overwrite length_code[255] to use the best encoding: | ||
272 | */ | ||
273 | _length_code[length-1] = (uch)code; | ||
274 | |||
275 | /* Initialize the mapping dist (0..32K) -> dist code (0..29) */ | ||
276 | dist = 0; | ||
277 | for (code = 0 ; code < 16; code++) { | ||
278 | base_dist[code] = dist; | ||
279 | for (n = 0; n < (1<<extra_dbits[code]); n++) { | ||
280 | _dist_code[dist++] = (uch)code; | ||
281 | } | ||
282 | } | ||
283 | Assert (dist == 256, "tr_static_init: dist != 256"); | ||
284 | dist >>= 7; /* from now on, all distances are divided by 128 */ | ||
285 | for ( ; code < D_CODES; code++) { | ||
286 | base_dist[code] = dist << 7; | ||
287 | for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) { | ||
288 | _dist_code[256 + dist++] = (uch)code; | ||
289 | } | ||
290 | } | ||
291 | Assert (dist == 256, "tr_static_init: 256+dist != 512"); | ||
292 | |||
293 | /* Construct the codes of the static literal tree */ | ||
294 | for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0; | ||
295 | n = 0; | ||
296 | while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++; | ||
297 | while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++; | ||
298 | while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++; | ||
299 | while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++; | ||
300 | /* Codes 286 and 287 do not exist, but we must include them in the | ||
301 | * tree construction to get a canonical Huffman tree (longest code | ||
302 | * all ones) | ||
303 | */ | ||
304 | gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count); | ||
305 | |||
306 | /* The static distance tree is trivial: */ | ||
307 | for (n = 0; n < D_CODES; n++) { | ||
308 | static_dtree[n].Len = 5; | ||
309 | static_dtree[n].Code = bi_reverse((unsigned)n, 5); | ||
310 | } | ||
311 | static_init_done = 1; | ||
312 | |||
313 | # ifdef GEN_TREES_H | ||
314 | gen_trees_header(); | ||
315 | # endif | ||
316 | #endif /* defined(GEN_TREES_H) || !defined(STDC) */ | ||
317 | } | ||
318 | |||
319 | /* =========================================================================== | ||
320 | * Genererate the file trees.h describing the static trees. | ||
321 | */ | ||
322 | #ifdef GEN_TREES_H | ||
323 | # ifndef DEBUG | ||
324 | # include <stdio.h> | ||
325 | # endif | ||
326 | |||
327 | # define SEPARATOR(i, last, width) \ | ||
328 | ((i) == (last)? "\n};\n\n" : \ | ||
329 | ((i) % (width) == (width)-1 ? ",\n" : ", ")) | ||
330 | |||
331 | void gen_trees_header() | ||
332 | { | ||
333 | FILE *header = fopen("trees.h", "w"); | ||
334 | int i; | ||
335 | |||
336 | Assert (header != NULL, "Can't open trees.h"); | ||
337 | fprintf(header, | ||
338 | "/* header created automatically with -DGEN_TREES_H */\n\n"); | ||
339 | |||
340 | fprintf(header, "local const ct_data static_ltree[L_CODES+2] = {\n"); | ||
341 | for (i = 0; i < L_CODES+2; i++) { | ||
342 | fprintf(header, "{{%3u},{%3u}}%s", static_ltree[i].Code, | ||
343 | static_ltree[i].Len, SEPARATOR(i, L_CODES+1, 5)); | ||
344 | } | ||
345 | |||
346 | fprintf(header, "local const ct_data static_dtree[D_CODES] = {\n"); | ||
347 | for (i = 0; i < D_CODES; i++) { | ||
348 | fprintf(header, "{{%2u},{%2u}}%s", static_dtree[i].Code, | ||
349 | static_dtree[i].Len, SEPARATOR(i, D_CODES-1, 5)); | ||
350 | } | ||
351 | |||
352 | fprintf(header, "const uch _dist_code[DIST_CODE_LEN] = {\n"); | ||
353 | for (i = 0; i < DIST_CODE_LEN; i++) { | ||
354 | fprintf(header, "%2u%s", _dist_code[i], | ||
355 | SEPARATOR(i, DIST_CODE_LEN-1, 20)); | ||
356 | } | ||
357 | |||
358 | fprintf(header, "const uch _length_code[MAX_MATCH-MIN_MATCH+1]= {\n"); | ||
359 | for (i = 0; i < MAX_MATCH-MIN_MATCH+1; i++) { | ||
360 | fprintf(header, "%2u%s", _length_code[i], | ||
361 | SEPARATOR(i, MAX_MATCH-MIN_MATCH, 20)); | ||
362 | } | ||
363 | |||
364 | fprintf(header, "local const int base_length[LENGTH_CODES] = {\n"); | ||
365 | for (i = 0; i < LENGTH_CODES; i++) { | ||
366 | fprintf(header, "%1u%s", base_length[i], | ||
367 | SEPARATOR(i, LENGTH_CODES-1, 20)); | ||
368 | } | ||
369 | |||
370 | fprintf(header, "local const int base_dist[D_CODES] = {\n"); | ||
371 | for (i = 0; i < D_CODES; i++) { | ||
372 | fprintf(header, "%5u%s", base_dist[i], | ||
373 | SEPARATOR(i, D_CODES-1, 10)); | ||
374 | } | ||
375 | |||
376 | fclose(header); | ||
377 | } | ||
378 | #endif /* GEN_TREES_H */ | ||
379 | |||
380 | /* =========================================================================== | ||
381 | * Initialize the tree data structures for a new zlib stream. | ||
382 | */ | ||
383 | void _tr_init(s) | ||
384 | deflate_state *s; | ||
385 | { | ||
386 | tr_static_init(); | ||
387 | |||
388 | s->l_desc.dyn_tree = s->dyn_ltree; | ||
389 | s->l_desc.stat_desc = &static_l_desc; | ||
390 | |||
391 | s->d_desc.dyn_tree = s->dyn_dtree; | ||
392 | s->d_desc.stat_desc = &static_d_desc; | ||
393 | |||
394 | s->bl_desc.dyn_tree = s->bl_tree; | ||
395 | s->bl_desc.stat_desc = &static_bl_desc; | ||
396 | |||
397 | s->bi_buf = 0; | ||
398 | s->bi_valid = 0; | ||
399 | s->last_eob_len = 8; /* enough lookahead for inflate */ | ||
400 | #ifdef DEBUG | ||
401 | s->compressed_len = 0L; | ||
402 | s->bits_sent = 0L; | ||
403 | #endif | ||
404 | |||
405 | /* Initialize the first block of the first file: */ | ||
406 | init_block(s); | ||
407 | } | ||
408 | |||
409 | /* =========================================================================== | ||
410 | * Initialize a new block. | ||
411 | */ | ||
412 | local void init_block(s) | ||
413 | deflate_state *s; | ||
414 | { | ||
415 | int n; /* iterates over tree elements */ | ||
416 | |||
417 | /* Initialize the trees. */ | ||
418 | for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0; | ||
419 | for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0; | ||
420 | for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0; | ||
421 | |||
422 | s->dyn_ltree[END_BLOCK].Freq = 1; | ||
423 | s->opt_len = s->static_len = 0L; | ||
424 | s->last_lit = s->matches = 0; | ||
425 | } | ||
426 | |||
427 | #define SMALLEST 1 | ||
428 | /* Index within the heap array of least frequent node in the Huffman tree */ | ||
429 | |||
430 | |||
431 | /* =========================================================================== | ||
432 | * Remove the smallest element from the heap and recreate the heap with | ||
433 | * one less element. Updates heap and heap_len. | ||
434 | */ | ||
435 | #define pqremove(s, tree, top) \ | ||
436 | {\ | ||
437 | top = s->heap[SMALLEST]; \ | ||
438 | s->heap[SMALLEST] = s->heap[s->heap_len--]; \ | ||
439 | pqdownheap(s, tree, SMALLEST); \ | ||
440 | } | ||
441 | |||
442 | /* =========================================================================== | ||
443 | * Compares to subtrees, using the tree depth as tie breaker when | ||
444 | * the subtrees have equal frequency. This minimizes the worst case length. | ||
445 | */ | ||
446 | #define smaller(tree, n, m, depth) \ | ||
447 | (tree[n].Freq < tree[m].Freq || \ | ||
448 | (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m])) | ||
449 | |||
450 | /* =========================================================================== | ||
451 | * Restore the heap property by moving down the tree starting at node k, | ||
452 | * exchanging a node with the smallest of its two sons if necessary, stopping | ||
453 | * when the heap property is re-established (each father smaller than its | ||
454 | * two sons). | ||
455 | */ | ||
456 | local void pqdownheap(s, tree, k) | ||
457 | deflate_state *s; | ||
458 | ct_data *tree; /* the tree to restore */ | ||
459 | int k; /* node to move down */ | ||
460 | { | ||
461 | int v = s->heap[k]; | ||
462 | int j = k << 1; /* left son of k */ | ||
463 | while (j <= s->heap_len) { | ||
464 | /* Set j to the smallest of the two sons: */ | ||
465 | if (j < s->heap_len && | ||
466 | smaller(tree, s->heap[j+1], s->heap[j], s->depth)) { | ||
467 | j++; | ||
468 | } | ||
469 | /* Exit if v is smaller than both sons */ | ||
470 | if (smaller(tree, v, s->heap[j], s->depth)) break; | ||
471 | |||
472 | /* Exchange v with the smallest son */ | ||
473 | s->heap[k] = s->heap[j]; k = j; | ||
474 | |||
475 | /* And continue down the tree, setting j to the left son of k */ | ||
476 | j <<= 1; | ||
477 | } | ||
478 | s->heap[k] = v; | ||
479 | } | ||
480 | |||
481 | /* =========================================================================== | ||
482 | * Compute the optimal bit lengths for a tree and update the total bit length | ||
483 | * for the current block. | ||
484 | * IN assertion: the fields freq and dad are set, heap[heap_max] and | ||
485 | * above are the tree nodes sorted by increasing frequency. | ||
486 | * OUT assertions: the field len is set to the optimal bit length, the | ||
487 | * array bl_count contains the frequencies for each bit length. | ||
488 | * The length opt_len is updated; static_len is also updated if stree is | ||
489 | * not null. | ||
490 | */ | ||
491 | local void gen_bitlen(s, desc) | ||
492 | deflate_state *s; | ||
493 | tree_desc *desc; /* the tree descriptor */ | ||
494 | { | ||
495 | ct_data *tree = desc->dyn_tree; | ||
496 | int max_code = desc->max_code; | ||
497 | const ct_data *stree = desc->stat_desc->static_tree; | ||
498 | const intf *extra = desc->stat_desc->extra_bits; | ||
499 | int base = desc->stat_desc->extra_base; | ||
500 | int max_length = desc->stat_desc->max_length; | ||
501 | int h; /* heap index */ | ||
502 | int n, m; /* iterate over the tree elements */ | ||
503 | int bits; /* bit length */ | ||
504 | int xbits; /* extra bits */ | ||
505 | ush f; /* frequency */ | ||
506 | int overflow = 0; /* number of elements with bit length too large */ | ||
507 | |||
508 | for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0; | ||
509 | |||
510 | /* In a first pass, compute the optimal bit lengths (which may | ||
511 | * overflow in the case of the bit length tree). | ||
512 | */ | ||
513 | tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */ | ||
514 | |||
515 | for (h = s->heap_max+1; h < HEAP_SIZE; h++) { | ||
516 | n = s->heap[h]; | ||
517 | bits = tree[tree[n].Dad].Len + 1; | ||
518 | if (bits > max_length) bits = max_length, overflow++; | ||
519 | tree[n].Len = (ush)bits; | ||
520 | /* We overwrite tree[n].Dad which is no longer needed */ | ||
521 | |||
522 | if (n > max_code) continue; /* not a leaf node */ | ||
523 | |||
524 | s->bl_count[bits]++; | ||
525 | xbits = 0; | ||
526 | if (n >= base) xbits = extra[n-base]; | ||
527 | f = tree[n].Freq; | ||
528 | s->opt_len += (ulg)f * (bits + xbits); | ||
529 | if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits); | ||
530 | } | ||
531 | if (overflow == 0) return; | ||
532 | |||
533 | Trace((stderr,"\nbit length overflow\n")); | ||
534 | /* This happens for example on obj2 and pic of the Calgary corpus */ | ||
535 | |||
536 | /* Find the first bit length which could increase: */ | ||
537 | do { | ||
538 | bits = max_length-1; | ||
539 | while (s->bl_count[bits] == 0) bits--; | ||
540 | s->bl_count[bits]--; /* move one leaf down the tree */ | ||
541 | s->bl_count[bits+1] += 2; /* move one overflow item as its brother */ | ||
542 | s->bl_count[max_length]--; | ||
543 | /* The brother of the overflow item also moves one step up, | ||
544 | * but this does not affect bl_count[max_length] | ||
545 | */ | ||
546 | overflow -= 2; | ||
547 | } while (overflow > 0); | ||
548 | |||
549 | /* Now recompute all bit lengths, scanning in increasing frequency. | ||
550 | * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all | ||
551 | * lengths instead of fixing only the wrong ones. This idea is taken | ||
552 | * from 'ar' written by Haruhiko Okumura.) | ||
553 | */ | ||
554 | for (bits = max_length; bits != 0; bits--) { | ||
555 | n = s->bl_count[bits]; | ||
556 | while (n != 0) { | ||
557 | m = s->heap[--h]; | ||
558 | if (m > max_code) continue; | ||
559 | if (tree[m].Len != (unsigned) bits) { | ||
560 | Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits)); | ||
561 | s->opt_len += ((long)bits - (long)tree[m].Len) | ||
562 | *(long)tree[m].Freq; | ||
563 | tree[m].Len = (ush)bits; | ||
564 | } | ||
565 | n--; | ||
566 | } | ||
567 | } | ||
568 | } | ||
569 | |||
570 | /* =========================================================================== | ||
571 | * Generate the codes for a given tree and bit counts (which need not be | ||
572 | * optimal). | ||
573 | * IN assertion: the array bl_count contains the bit length statistics for | ||
574 | * the given tree and the field len is set for all tree elements. | ||
575 | * OUT assertion: the field code is set for all tree elements of non | ||
576 | * zero code length. | ||
577 | */ | ||
578 | local void gen_codes (tree, max_code, bl_count) | ||
579 | ct_data *tree; /* the tree to decorate */ | ||
580 | int max_code; /* largest code with non zero frequency */ | ||
581 | ushf *bl_count; /* number of codes at each bit length */ | ||
582 | { | ||
583 | ush next_code[MAX_BITS+1]; /* next code value for each bit length */ | ||
584 | ush code = 0; /* running code value */ | ||
585 | int bits; /* bit index */ | ||
586 | int n; /* code index */ | ||
587 | |||
588 | /* The distribution counts are first used to generate the code values | ||
589 | * without bit reversal. | ||
590 | */ | ||
591 | for (bits = 1; bits <= MAX_BITS; bits++) { | ||
592 | next_code[bits] = code = (code + bl_count[bits-1]) << 1; | ||
593 | } | ||
594 | /* Check that the bit counts in bl_count are consistent. The last code | ||
595 | * must be all ones. | ||
596 | */ | ||
597 | Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1, | ||
598 | "inconsistent bit counts"); | ||
599 | Tracev((stderr,"\ngen_codes: max_code %d ", max_code)); | ||
600 | |||
601 | for (n = 0; n <= max_code; n++) { | ||
602 | int len = tree[n].Len; | ||
603 | if (len == 0) continue; | ||
604 | /* Now reverse the bits */ | ||
605 | tree[n].Code = bi_reverse(next_code[len]++, len); | ||
606 | |||
607 | Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ", | ||
608 | n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1)); | ||
609 | } | ||
610 | } | ||
611 | |||
612 | /* =========================================================================== | ||
613 | * Construct one Huffman tree and assigns the code bit strings and lengths. | ||
614 | * Update the total bit length for the current block. | ||
615 | * IN assertion: the field freq is set for all tree elements. | ||
616 | * OUT assertions: the fields len and code are set to the optimal bit length | ||
617 | * and corresponding code. The length opt_len is updated; static_len is | ||
618 | * also updated if stree is not null. The field max_code is set. | ||
619 | */ | ||
620 | local void build_tree(s, desc) | ||
621 | deflate_state *s; | ||
622 | tree_desc *desc; /* the tree descriptor */ | ||
623 | { | ||
624 | ct_data *tree = desc->dyn_tree; | ||
625 | const ct_data *stree = desc->stat_desc->static_tree; | ||
626 | int elems = desc->stat_desc->elems; | ||
627 | int n, m; /* iterate over heap elements */ | ||
628 | int max_code = -1; /* largest code with non zero frequency */ | ||
629 | int node; /* new node being created */ | ||
630 | |||
631 | /* Construct the initial heap, with least frequent element in | ||
632 | * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1]. | ||
633 | * heap[0] is not used. | ||
634 | */ | ||
635 | s->heap_len = 0, s->heap_max = HEAP_SIZE; | ||
636 | |||
637 | for (n = 0; n < elems; n++) { | ||
638 | if (tree[n].Freq != 0) { | ||
639 | s->heap[++(s->heap_len)] = max_code = n; | ||
640 | s->depth[n] = 0; | ||
641 | } else { | ||
642 | tree[n].Len = 0; | ||
643 | } | ||
644 | } | ||
645 | |||
646 | /* The pkzip format requires that at least one distance code exists, | ||
647 | * and that at least one bit should be sent even if there is only one | ||
648 | * possible code. So to avoid special checks later on we force at least | ||
649 | * two codes of non zero frequency. | ||
650 | */ | ||
651 | while (s->heap_len < 2) { | ||
652 | node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0); | ||
653 | tree[node].Freq = 1; | ||
654 | s->depth[node] = 0; | ||
655 | s->opt_len--; if (stree) s->static_len -= stree[node].Len; | ||
656 | /* node is 0 or 1 so it does not have extra bits */ | ||
657 | } | ||
658 | desc->max_code = max_code; | ||
659 | |||
660 | /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree, | ||
661 | * establish sub-heaps of increasing lengths: | ||
662 | */ | ||
663 | for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, n); | ||
664 | |||
665 | /* Construct the Huffman tree by repeatedly combining the least two | ||
666 | * frequent nodes. | ||
667 | */ | ||
668 | node = elems; /* next internal node of the tree */ | ||
669 | do { | ||
670 | pqremove(s, tree, n); /* n = node of least frequency */ | ||
671 | m = s->heap[SMALLEST]; /* m = node of next least frequency */ | ||
672 | |||
673 | s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */ | ||
674 | s->heap[--(s->heap_max)] = m; | ||
675 | |||
676 | /* Create a new node father of n and m */ | ||
677 | tree[node].Freq = tree[n].Freq + tree[m].Freq; | ||
678 | s->depth[node] = (uch) (MAX(s->depth[n], s->depth[m]) + 1); | ||
679 | tree[n].Dad = tree[m].Dad = (ush)node; | ||
680 | #ifdef DUMP_BL_TREE | ||
681 | if (tree == s->bl_tree) { | ||
682 | fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)", | ||
683 | node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq); | ||
684 | } | ||
685 | #endif | ||
686 | /* and insert the new node in the heap */ | ||
687 | s->heap[SMALLEST] = node++; | ||
688 | pqdownheap(s, tree, SMALLEST); | ||
689 | |||
690 | } while (s->heap_len >= 2); | ||
691 | |||
692 | s->heap[--(s->heap_max)] = s->heap[SMALLEST]; | ||
693 | |||
694 | /* At this point, the fields freq and dad are set. We can now | ||
695 | * generate the bit lengths. | ||
696 | */ | ||
697 | gen_bitlen(s, (tree_desc *)desc); | ||
698 | |||
699 | /* The field len is now set, we can generate the bit codes */ | ||
700 | gen_codes ((ct_data *)tree, max_code, s->bl_count); | ||
701 | } | ||
702 | |||
703 | /* =========================================================================== | ||
704 | * Scan a literal or distance tree to determine the frequencies of the codes | ||
705 | * in the bit length tree. | ||
706 | */ | ||
707 | local void scan_tree (s, tree, max_code) | ||
708 | deflate_state *s; | ||
709 | ct_data *tree; /* the tree to be scanned */ | ||
710 | int max_code; /* and its largest code of non zero frequency */ | ||
711 | { | ||
712 | int n; /* iterates over all tree elements */ | ||
713 | int prevlen = -1; /* last emitted length */ | ||
714 | int curlen; /* length of current code */ | ||
715 | int nextlen = tree[0].Len; /* length of next code */ | ||
716 | int count = 0; /* repeat count of the current code */ | ||
717 | int max_count = 7; /* max repeat count */ | ||
718 | int min_count = 4; /* min repeat count */ | ||
719 | |||
720 | if (nextlen == 0) max_count = 138, min_count = 3; | ||
721 | tree[max_code+1].Len = (ush)0xffff; /* guard */ | ||
722 | |||
723 | for (n = 0; n <= max_code; n++) { | ||
724 | curlen = nextlen; nextlen = tree[n+1].Len; | ||
725 | if (++count < max_count && curlen == nextlen) { | ||
726 | continue; | ||
727 | } else if (count < min_count) { | ||
728 | s->bl_tree[curlen].Freq += count; | ||
729 | } else if (curlen != 0) { | ||
730 | if (curlen != prevlen) s->bl_tree[curlen].Freq++; | ||
731 | s->bl_tree[REP_3_6].Freq++; | ||
732 | } else if (count <= 10) { | ||
733 | s->bl_tree[REPZ_3_10].Freq++; | ||
734 | } else { | ||
735 | s->bl_tree[REPZ_11_138].Freq++; | ||
736 | } | ||
737 | count = 0; prevlen = curlen; | ||
738 | if (nextlen == 0) { | ||
739 | max_count = 138, min_count = 3; | ||
740 | } else if (curlen == nextlen) { | ||
741 | max_count = 6, min_count = 3; | ||
742 | } else { | ||
743 | max_count = 7, min_count = 4; | ||
744 | } | ||
745 | } | ||
746 | } | ||
747 | |||
748 | /* =========================================================================== | ||
749 | * Send a literal or distance tree in compressed form, using the codes in | ||
750 | * bl_tree. | ||
751 | */ | ||
752 | local void send_tree (s, tree, max_code) | ||
753 | deflate_state *s; | ||
754 | ct_data *tree; /* the tree to be scanned */ | ||
755 | int max_code; /* and its largest code of non zero frequency */ | ||
756 | { | ||
757 | int n; /* iterates over all tree elements */ | ||
758 | int prevlen = -1; /* last emitted length */ | ||
759 | int curlen; /* length of current code */ | ||
760 | int nextlen = tree[0].Len; /* length of next code */ | ||
761 | int count = 0; /* repeat count of the current code */ | ||
762 | int max_count = 7; /* max repeat count */ | ||
763 | int min_count = 4; /* min repeat count */ | ||
764 | |||
765 | /* tree[max_code+1].Len = -1; */ /* guard already set */ | ||
766 | if (nextlen == 0) max_count = 138, min_count = 3; | ||
767 | |||
768 | for (n = 0; n <= max_code; n++) { | ||
769 | curlen = nextlen; nextlen = tree[n+1].Len; | ||
770 | if (++count < max_count && curlen == nextlen) { | ||
771 | continue; | ||
772 | } else if (count < min_count) { | ||
773 | do { send_code(s, curlen, s->bl_tree); } while (--count != 0); | ||
774 | |||
775 | } else if (curlen != 0) { | ||
776 | if (curlen != prevlen) { | ||
777 | send_code(s, curlen, s->bl_tree); count--; | ||
778 | } | ||
779 | Assert(count >= 3 && count <= 6, " 3_6?"); | ||
780 | send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2); | ||
781 | |||
782 | } else if (count <= 10) { | ||
783 | send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3); | ||
784 | |||
785 | } else { | ||
786 | send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7); | ||
787 | } | ||
788 | count = 0; prevlen = curlen; | ||
789 | if (nextlen == 0) { | ||
790 | max_count = 138, min_count = 3; | ||
791 | } else if (curlen == nextlen) { | ||
792 | max_count = 6, min_count = 3; | ||
793 | } else { | ||
794 | max_count = 7, min_count = 4; | ||
795 | } | ||
796 | } | ||
797 | } | ||
798 | |||
799 | /* =========================================================================== | ||
800 | * Construct the Huffman tree for the bit lengths and return the index in | ||
801 | * bl_order of the last bit length code to send. | ||
802 | */ | ||
803 | local int build_bl_tree(s) | ||
804 | deflate_state *s; | ||
805 | { | ||
806 | int max_blindex; /* index of last bit length code of non zero freq */ | ||
807 | |||
808 | /* Determine the bit length frequencies for literal and distance trees */ | ||
809 | scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code); | ||
810 | scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code); | ||
811 | |||
812 | /* Build the bit length tree: */ | ||
813 | build_tree(s, (tree_desc *)(&(s->bl_desc))); | ||
814 | /* opt_len now includes the length of the tree representations, except | ||
815 | * the lengths of the bit lengths codes and the 5+5+4 bits for the counts. | ||
816 | */ | ||
817 | |||
818 | /* Determine the number of bit length codes to send. The pkzip format | ||
819 | * requires that at least 4 bit length codes be sent. (appnote.txt says | ||
820 | * 3 but the actual value used is 4.) | ||
821 | */ | ||
822 | for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) { | ||
823 | if (s->bl_tree[bl_order[max_blindex]].Len != 0) break; | ||
824 | } | ||
825 | /* Update opt_len to include the bit length tree and counts */ | ||
826 | s->opt_len += 3*(max_blindex+1) + 5+5+4; | ||
827 | Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld", | ||
828 | s->opt_len, s->static_len)); | ||
829 | |||
830 | return max_blindex; | ||
831 | } | ||
832 | |||
833 | /* =========================================================================== | ||
834 | * Send the header for a block using dynamic Huffman trees: the counts, the | ||
835 | * lengths of the bit length codes, the literal tree and the distance tree. | ||
836 | * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4. | ||
837 | */ | ||
838 | local void send_all_trees(s, lcodes, dcodes, blcodes) | ||
839 | deflate_state *s; | ||
840 | int lcodes, dcodes, blcodes; /* number of codes for each tree */ | ||
841 | { | ||
842 | int rank; /* index in bl_order */ | ||
843 | |||
844 | Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes"); | ||
845 | Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES, | ||
846 | "too many codes"); | ||
847 | Tracev((stderr, "\nbl counts: ")); | ||
848 | send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */ | ||
849 | send_bits(s, dcodes-1, 5); | ||
850 | send_bits(s, blcodes-4, 4); /* not -3 as stated in appnote.txt */ | ||
851 | for (rank = 0; rank < blcodes; rank++) { | ||
852 | Tracev((stderr, "\nbl code %2d ", bl_order[rank])); | ||
853 | send_bits(s, s->bl_tree[bl_order[rank]].Len, 3); | ||
854 | } | ||
855 | Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent)); | ||
856 | |||
857 | send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */ | ||
858 | Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent)); | ||
859 | |||
860 | send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */ | ||
861 | Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent)); | ||
862 | } | ||
863 | |||
864 | /* =========================================================================== | ||
865 | * Send a stored block | ||
866 | */ | ||
867 | void _tr_stored_block(s, buf, stored_len, eof) | ||
868 | deflate_state *s; | ||
869 | charf *buf; /* input block */ | ||
870 | ulg stored_len; /* length of input block */ | ||
871 | int eof; /* true if this is the last block for a file */ | ||
872 | { | ||
873 | send_bits(s, (STORED_BLOCK<<1)+eof, 3); /* send block type */ | ||
874 | #ifdef DEBUG | ||
875 | s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L; | ||
876 | s->compressed_len += (stored_len + 4) << 3; | ||
877 | #endif | ||
878 | copy_block(s, buf, (unsigned)stored_len, 1); /* with header */ | ||
879 | } | ||
880 | |||
881 | /* =========================================================================== | ||
882 | * Send one empty static block to give enough lookahead for inflate. | ||
883 | * This takes 10 bits, of which 7 may remain in the bit buffer. | ||
884 | * The current inflate code requires 9 bits of lookahead. If the | ||
885 | * last two codes for the previous block (real code plus EOB) were coded | ||
886 | * on 5 bits or less, inflate may have only 5+3 bits of lookahead to decode | ||
887 | * the last real code. In this case we send two empty static blocks instead | ||
888 | * of one. (There are no problems if the previous block is stored or fixed.) | ||
889 | * To simplify the code, we assume the worst case of last real code encoded | ||
890 | * on one bit only. | ||
891 | */ | ||
892 | void _tr_align(s) | ||
893 | deflate_state *s; | ||
894 | { | ||
895 | send_bits(s, STATIC_TREES<<1, 3); | ||
896 | send_code(s, END_BLOCK, static_ltree); | ||
897 | #ifdef DEBUG | ||
898 | s->compressed_len += 10L; /* 3 for block type, 7 for EOB */ | ||
899 | #endif | ||
900 | bi_flush(s); | ||
901 | /* Of the 10 bits for the empty block, we have already sent | ||
902 | * (10 - bi_valid) bits. The lookahead for the last real code (before | ||
903 | * the EOB of the previous block) was thus at least one plus the length | ||
904 | * of the EOB plus what we have just sent of the empty static block. | ||
905 | */ | ||
906 | if (1 + s->last_eob_len + 10 - s->bi_valid < 9) { | ||
907 | send_bits(s, STATIC_TREES<<1, 3); | ||
908 | send_code(s, END_BLOCK, static_ltree); | ||
909 | #ifdef DEBUG | ||
910 | s->compressed_len += 10L; | ||
911 | #endif | ||
912 | bi_flush(s); | ||
913 | } | ||
914 | s->last_eob_len = 7; | ||
915 | } | ||
916 | |||
917 | /* =========================================================================== | ||
918 | * Determine the best encoding for the current block: dynamic trees, static | ||
919 | * trees or store, and output the encoded block to the zip file. | ||
920 | */ | ||
921 | void _tr_flush_block(s, buf, stored_len, eof) | ||
922 | deflate_state *s; | ||
923 | charf *buf; /* input block, or NULL if too old */ | ||
924 | ulg stored_len; /* length of input block */ | ||
925 | int eof; /* true if this is the last block for a file */ | ||
926 | { | ||
927 | ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */ | ||
928 | int max_blindex = 0; /* index of last bit length code of non zero freq */ | ||
929 | |||
930 | /* Build the Huffman trees unless a stored block is forced */ | ||
931 | if (s->level > 0) { | ||
932 | |||
933 | /* Check if the file is ascii or binary */ | ||
934 | if (s->data_type == Z_UNKNOWN) set_data_type(s); | ||
935 | |||
936 | /* Construct the literal and distance trees */ | ||
937 | build_tree(s, (tree_desc *)(&(s->l_desc))); | ||
938 | Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len, | ||
939 | s->static_len)); | ||
940 | |||
941 | build_tree(s, (tree_desc *)(&(s->d_desc))); | ||
942 | Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len, | ||
943 | s->static_len)); | ||
944 | /* At this point, opt_len and static_len are the total bit lengths of | ||
945 | * the compressed block data, excluding the tree representations. | ||
946 | */ | ||
947 | |||
948 | /* Build the bit length tree for the above two trees, and get the index | ||
949 | * in bl_order of the last bit length code to send. | ||
950 | */ | ||
951 | max_blindex = build_bl_tree(s); | ||
952 | |||
953 | /* Determine the best encoding. Compute first the block length in bytes*/ | ||
954 | opt_lenb = (s->opt_len+3+7)>>3; | ||
955 | static_lenb = (s->static_len+3+7)>>3; | ||
956 | |||
957 | Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ", | ||
958 | opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len, | ||
959 | s->last_lit)); | ||
960 | |||
961 | if (static_lenb <= opt_lenb) opt_lenb = static_lenb; | ||
962 | |||
963 | } else { | ||
964 | Assert(buf != (char*)0, "lost buf"); | ||
965 | opt_lenb = static_lenb = stored_len + 5; /* force a stored block */ | ||
966 | } | ||
967 | |||
968 | #ifdef FORCE_STORED | ||
969 | if (buf != (char*)0) { /* force stored block */ | ||
970 | #else | ||
971 | if (stored_len+4 <= opt_lenb && buf != (char*)0) { | ||
972 | /* 4: two words for the lengths */ | ||
973 | #endif | ||
974 | /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE. | ||
975 | * Otherwise we can't have processed more than WSIZE input bytes since | ||
976 | * the last block flush, because compression would have been | ||
977 | * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to | ||
978 | * transform a block into a stored block. | ||
979 | */ | ||
980 | _tr_stored_block(s, buf, stored_len, eof); | ||
981 | |||
982 | #ifdef FORCE_STATIC | ||
983 | } else if (static_lenb >= 0) { /* force static trees */ | ||
984 | #else | ||
985 | } else if (static_lenb == opt_lenb) { | ||
986 | #endif | ||
987 | send_bits(s, (STATIC_TREES<<1)+eof, 3); | ||
988 | compress_block(s, (ct_data *)static_ltree, (ct_data *)static_dtree); | ||
989 | #ifdef DEBUG | ||
990 | s->compressed_len += 3 + s->static_len; | ||
991 | #endif | ||
992 | } else { | ||
993 | send_bits(s, (DYN_TREES<<1)+eof, 3); | ||
994 | send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1, | ||
995 | max_blindex+1); | ||
996 | compress_block(s, (ct_data *)s->dyn_ltree, (ct_data *)s->dyn_dtree); | ||
997 | #ifdef DEBUG | ||
998 | s->compressed_len += 3 + s->opt_len; | ||
999 | #endif | ||
1000 | } | ||
1001 | Assert (s->compressed_len == s->bits_sent, "bad compressed size"); | ||
1002 | /* The above check is made mod 2^32, for files larger than 512 MB | ||
1003 | * and uLong implemented on 32 bits. | ||
1004 | */ | ||
1005 | init_block(s); | ||
1006 | |||
1007 | if (eof) { | ||
1008 | bi_windup(s); | ||
1009 | #ifdef DEBUG | ||
1010 | s->compressed_len += 7; /* align on byte boundary */ | ||
1011 | #endif | ||
1012 | } | ||
1013 | Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3, | ||
1014 | s->compressed_len-7*eof)); | ||
1015 | } | ||
1016 | |||
1017 | /* =========================================================================== | ||
1018 | * Save the match info and tally the frequency counts. Return true if | ||
1019 | * the current block must be flushed. | ||
1020 | */ | ||
1021 | int _tr_tally (s, dist, lc) | ||
1022 | deflate_state *s; | ||
1023 | unsigned dist; /* distance of matched string */ | ||
1024 | unsigned lc; /* match length-MIN_MATCH or unmatched char (if dist==0) */ | ||
1025 | { | ||
1026 | s->d_buf[s->last_lit] = (ush)dist; | ||
1027 | s->l_buf[s->last_lit++] = (uch)lc; | ||
1028 | if (dist == 0) { | ||
1029 | /* lc is the unmatched char */ | ||
1030 | s->dyn_ltree[lc].Freq++; | ||
1031 | } else { | ||
1032 | s->matches++; | ||
1033 | /* Here, lc is the match length - MIN_MATCH */ | ||
1034 | dist--; /* dist = match distance - 1 */ | ||
1035 | Assert((ush)dist < (ush)MAX_DIST(s) && | ||
1036 | (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) && | ||
1037 | (ush)d_code(dist) < (ush)D_CODES, "_tr_tally: bad match"); | ||
1038 | |||
1039 | s->dyn_ltree[_length_code[lc]+LITERALS+1].Freq++; | ||
1040 | s->dyn_dtree[d_code(dist)].Freq++; | ||
1041 | } | ||
1042 | |||
1043 | #ifdef TRUNCATE_BLOCK | ||
1044 | /* Try to guess if it is profitable to stop the current block here */ | ||
1045 | if ((s->last_lit & 0x1fff) == 0 && s->level > 2) { | ||
1046 | /* Compute an upper bound for the compressed length */ | ||
1047 | ulg out_length = (ulg)s->last_lit*8L; | ||
1048 | ulg in_length = (ulg)((long)s->strstart - s->block_start); | ||
1049 | int dcode; | ||
1050 | for (dcode = 0; dcode < D_CODES; dcode++) { | ||
1051 | out_length += (ulg)s->dyn_dtree[dcode].Freq * | ||
1052 | (5L+extra_dbits[dcode]); | ||
1053 | } | ||
1054 | out_length >>= 3; | ||
1055 | Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ", | ||
1056 | s->last_lit, in_length, out_length, | ||
1057 | 100L - out_length*100L/in_length)); | ||
1058 | if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1; | ||
1059 | } | ||
1060 | #endif | ||
1061 | return (s->last_lit == s->lit_bufsize-1); | ||
1062 | /* We avoid equality with lit_bufsize because of wraparound at 64K | ||
1063 | * on 16 bit machines and because stored blocks are restricted to | ||
1064 | * 64K-1 bytes. | ||
1065 | */ | ||
1066 | } | ||
1067 | |||
1068 | /* =========================================================================== | ||
1069 | * Send the block data compressed using the given Huffman trees | ||
1070 | */ | ||
1071 | local void compress_block(s, ltree, dtree) | ||
1072 | deflate_state *s; | ||
1073 | ct_data *ltree; /* literal tree */ | ||
1074 | ct_data *dtree; /* distance tree */ | ||
1075 | { | ||
1076 | unsigned dist; /* distance of matched string */ | ||
1077 | int lc; /* match length or unmatched char (if dist == 0) */ | ||
1078 | unsigned lx = 0; /* running index in l_buf */ | ||
1079 | unsigned code; /* the code to send */ | ||
1080 | int extra; /* number of extra bits to send */ | ||
1081 | |||
1082 | if (s->last_lit != 0) do { | ||
1083 | dist = s->d_buf[lx]; | ||
1084 | lc = s->l_buf[lx++]; | ||
1085 | if (dist == 0) { | ||
1086 | send_code(s, lc, ltree); /* send a literal byte */ | ||
1087 | Tracecv(isgraph(lc), (stderr," '%c' ", lc)); | ||
1088 | } else { | ||
1089 | /* Here, lc is the match length - MIN_MATCH */ | ||
1090 | code = _length_code[lc]; | ||
1091 | send_code(s, code+LITERALS+1, ltree); /* send the length code */ | ||
1092 | extra = extra_lbits[code]; | ||
1093 | if (extra != 0) { | ||
1094 | lc -= base_length[code]; | ||
1095 | send_bits(s, lc, extra); /* send the extra length bits */ | ||
1096 | } | ||
1097 | dist--; /* dist is now the match distance - 1 */ | ||
1098 | code = d_code(dist); | ||
1099 | Assert (code < D_CODES, "bad d_code"); | ||
1100 | |||
1101 | send_code(s, code, dtree); /* send the distance code */ | ||
1102 | extra = extra_dbits[code]; | ||
1103 | if (extra != 0) { | ||
1104 | dist -= base_dist[code]; | ||
1105 | send_bits(s, dist, extra); /* send the extra distance bits */ | ||
1106 | } | ||
1107 | } /* literal or match pair ? */ | ||
1108 | |||
1109 | /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */ | ||
1110 | Assert(s->pending < s->lit_bufsize + 2*lx, "pendingBuf overflow"); | ||
1111 | |||
1112 | } while (lx < s->last_lit); | ||
1113 | |||
1114 | send_code(s, END_BLOCK, ltree); | ||
1115 | s->last_eob_len = ltree[END_BLOCK].Len; | ||
1116 | } | ||
1117 | |||
1118 | /* =========================================================================== | ||
1119 | * Set the data type to ASCII or BINARY, using a crude approximation: | ||
1120 | * binary if more than 20% of the bytes are <= 6 or >= 128, ascii otherwise. | ||
1121 | * IN assertion: the fields freq of dyn_ltree are set and the total of all | ||
1122 | * frequencies does not exceed 64K (to fit in an int on 16 bit machines). | ||
1123 | */ | ||
1124 | local void set_data_type(s) | ||
1125 | deflate_state *s; | ||
1126 | { | ||
1127 | int n = 0; | ||
1128 | unsigned ascii_freq = 0; | ||
1129 | unsigned bin_freq = 0; | ||
1130 | while (n < 7) bin_freq += s->dyn_ltree[n++].Freq; | ||
1131 | while (n < 128) ascii_freq += s->dyn_ltree[n++].Freq; | ||
1132 | while (n < LITERALS) bin_freq += s->dyn_ltree[n++].Freq; | ||
1133 | s->data_type = (Byte)(bin_freq > (ascii_freq >> 2) ? Z_BINARY : Z_ASCII); | ||
1134 | } | ||
1135 | |||
1136 | /* =========================================================================== | ||
1137 | * Reverse the first len bits of a code, using straightforward code (a faster | ||
1138 | * method would use a table) | ||
1139 | * IN assertion: 1 <= len <= 15 | ||
1140 | */ | ||
1141 | local unsigned bi_reverse(code, len) | ||
1142 | unsigned code; /* the value to invert */ | ||
1143 | int len; /* its bit length */ | ||
1144 | { | ||
1145 | register unsigned res = 0; | ||
1146 | do { | ||
1147 | res |= code & 1; | ||
1148 | code >>= 1, res <<= 1; | ||
1149 | } while (--len > 0); | ||
1150 | return res >> 1; | ||
1151 | } | ||
1152 | |||
1153 | /* =========================================================================== | ||
1154 | * Flush the bit buffer, keeping at most 7 bits in it. | ||
1155 | */ | ||
1156 | local void bi_flush(s) | ||
1157 | deflate_state *s; | ||
1158 | { | ||
1159 | if (s->bi_valid == 16) { | ||
1160 | put_short(s, s->bi_buf); | ||
1161 | s->bi_buf = 0; | ||
1162 | s->bi_valid = 0; | ||
1163 | } else if (s->bi_valid >= 8) { | ||
1164 | put_byte(s, (Byte)s->bi_buf); | ||
1165 | s->bi_buf >>= 8; | ||
1166 | s->bi_valid -= 8; | ||
1167 | } | ||
1168 | } | ||
1169 | |||
1170 | /* =========================================================================== | ||
1171 | * Flush the bit buffer and align the output on a byte boundary | ||
1172 | */ | ||
1173 | local void bi_windup(s) | ||
1174 | deflate_state *s; | ||
1175 | { | ||
1176 | if (s->bi_valid > 8) { | ||
1177 | put_short(s, s->bi_buf); | ||
1178 | } else if (s->bi_valid > 0) { | ||
1179 | put_byte(s, (Byte)s->bi_buf); | ||
1180 | } | ||
1181 | s->bi_buf = 0; | ||
1182 | s->bi_valid = 0; | ||
1183 | #ifdef DEBUG | ||
1184 | s->bits_sent = (s->bits_sent+7) & ~7; | ||
1185 | #endif | ||
1186 | } | ||
1187 | |||
1188 | /* =========================================================================== | ||
1189 | * Copy a stored block, storing first the length and its | ||
1190 | * one's complement if requested. | ||
1191 | */ | ||
1192 | local void copy_block(s, buf, len, header) | ||
1193 | deflate_state *s; | ||
1194 | charf *buf; /* the input data */ | ||
1195 | unsigned len; /* its length */ | ||
1196 | int header; /* true if block header must be written */ | ||
1197 | { | ||
1198 | bi_windup(s); /* align on byte boundary */ | ||
1199 | s->last_eob_len = 8; /* enough lookahead for inflate */ | ||
1200 | |||
1201 | if (header) { | ||
1202 | put_short(s, (ush)len); | ||
1203 | put_short(s, (ush)~len); | ||
1204 | #ifdef DEBUG | ||
1205 | s->bits_sent += 2*16; | ||
1206 | #endif | ||
1207 | } | ||
1208 | #ifdef DEBUG | ||
1209 | s->bits_sent += (ulg)len<<3; | ||
1210 | #endif | ||
1211 | while (len--) { | ||
1212 | put_byte(s, *buf++); | ||
1213 | } | ||
1214 | } | ||