Revert "Hide nonfunctional NEON options in aarch64"
[pcsx_rearmed.git] / deps / trees.c
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JAS
1/* trees.c -- output deflated data using Huffman coding
2 * Copyright (C) 1995-2012 Jean-loup Gailly
3 * detect_data_type() function provided freely by Cosmin Truta, 2006
4 * For conditions of distribution and use, see copyright notice in zlib.h
5 */
6
7/*
8 * ALGORITHM
9 *
10 * The "deflation" process uses several Huffman trees. The more
11 * common source values are represented by shorter bit sequences.
12 *
13 * Each code tree is stored in a compressed form which is itself
14 * a Huffman encoding of the lengths of all the code strings (in
15 * ascending order by source values). The actual code strings are
16 * reconstructed from the lengths in the inflate process, as described
17 * in the deflate specification.
18 *
19 * REFERENCES
20 *
21 * Deutsch, L.P.,"'Deflate' Compressed Data Format Specification".
22 * Available in ftp.uu.net:/pub/archiving/zip/doc/deflate-1.1.doc
23 *
24 * Storer, James A.
25 * Data Compression: Methods and Theory, pp. 49-50.
26 * Computer Science Press, 1988. ISBN 0-7167-8156-5.
27 *
28 * Sedgewick, R.
29 * Algorithms, p290.
30 * Addison-Wesley, 1983. ISBN 0-201-06672-6.
31 */
32
33/* @(#) $Id$ */
34
35/* #define GEN_TREES_H */
36
37#include "deflate.h"
38
39#ifdef DEBUG
40# include <ctype.h>
41#endif
42
43/* ===========================================================================
44 * Constants
45 */
46
47#define MAX_BL_BITS 7
48/* Bit length codes must not exceed MAX_BL_BITS bits */
49
50#define END_BLOCK 256
51/* end of block literal code */
52
53#define REP_3_6 16
54/* repeat previous bit length 3-6 times (2 bits of repeat count) */
55
56#define REPZ_3_10 17
57/* repeat a zero length 3-10 times (3 bits of repeat count) */
58
59#define REPZ_11_138 18
60/* repeat a zero length 11-138 times (7 bits of repeat count) */
61
62local const int extra_lbits[LENGTH_CODES] /* extra bits for each length code */
63= {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};
64
65local const int extra_dbits[D_CODES] /* extra bits for each distance code */
66= {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};
67
68local const int extra_blbits[BL_CODES]/* extra bits for each bit length code */
69= {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7};
70
71local const uch bl_order[BL_CODES]
72= {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15};
73/* The lengths of the bit length codes are sent in order of decreasing
74 * probability, to avoid transmitting the lengths for unused bit length codes.
75 */
76
77/* ===========================================================================
78 * Local data. These are initialized only once.
79 */
80
81#define DIST_CODE_LEN 512 /* see definition of array dist_code below */
82
83#if defined(GEN_TREES_H) || !defined(STDC)
84/* non ANSI compilers may not accept trees.h */
85
86local ct_data static_ltree[L_CODES+2];
87/* The static literal tree. Since the bit lengths are imposed, there is no
88 * need for the L_CODES extra codes used during heap construction. However
89 * The codes 286 and 287 are needed to build a canonical tree (see _tr_init
90 * below).
91 */
92
93local ct_data static_dtree[D_CODES];
94/* The static distance tree. (Actually a trivial tree since all codes use
95 * 5 bits.)
96 */
97
98uch _dist_code[DIST_CODE_LEN];
99/* Distance codes. The first 256 values correspond to the distances
100 * 3 .. 258, the last 256 values correspond to the top 8 bits of
101 * the 15 bit distances.
102 */
103
104uch _length_code[MAX_MATCH-MIN_MATCH+1];
105/* length code for each normalized match length (0 == MIN_MATCH) */
106
107local int base_length[LENGTH_CODES];
108/* First normalized length for each code (0 = MIN_MATCH) */
109
110local int base_dist[D_CODES];
111/* First normalized distance for each code (0 = distance of 1) */
112
113#else
114# include "trees.h"
115#endif /* GEN_TREES_H */
116
117struct static_tree_desc_s {
118 const ct_data *static_tree; /* static tree or NULL */
119 const intf *extra_bits; /* extra bits for each code or NULL */
120 int extra_base; /* base index for extra_bits */
121 int elems; /* max number of elements in the tree */
122 int max_length; /* max bit length for the codes */
123};
124
125local static_tree_desc static_l_desc =
126{static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS};
127
128local static_tree_desc static_d_desc =
129{static_dtree, extra_dbits, 0, D_CODES, MAX_BITS};
130
131local static_tree_desc static_bl_desc =
132{(const ct_data *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS};
133
134/* ===========================================================================
135 * Local (static) routines in this file.
136 */
137
138local void tr_static_init OF((void));
139local void init_block OF((deflate_state *s));
140local void pqdownheap OF((deflate_state *s, ct_data *tree, int k));
141local void gen_bitlen OF((deflate_state *s, tree_desc *desc));
142local void gen_codes OF((ct_data *tree, int max_code, ushf *bl_count));
143local void build_tree OF((deflate_state *s, tree_desc *desc));
144local void scan_tree OF((deflate_state *s, ct_data *tree, int max_code));
145local void send_tree OF((deflate_state *s, ct_data *tree, int max_code));
146local int build_bl_tree OF((deflate_state *s));
147local void send_all_trees OF((deflate_state *s, int lcodes, int dcodes,
148 int blcodes));
149local void compress_block OF((deflate_state *s, const ct_data *ltree,
150 const ct_data *dtree));
151local int detect_data_type OF((deflate_state *s));
152local unsigned bi_reverse OF((unsigned value, int length));
153local void bi_windup OF((deflate_state *s));
154local void bi_flush OF((deflate_state *s));
155local void copy_block OF((deflate_state *s, charf *buf, unsigned len,
156 int header));
157
158#ifdef GEN_TREES_H
159local void gen_trees_header OF((void));
160#endif
161
162#ifndef DEBUG
163# define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len)
164/* Send a code of the given tree. c and tree must not have side effects */
165
166#else /* DEBUG */
167# define send_code(s, c, tree) \
168{ if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \
169 send_bits(s, tree[c].Code, tree[c].Len); }
170#endif
171
172/* ===========================================================================
173 * Output a short LSB first on the stream.
174 * IN assertion: there is enough room in pendingBuf.
175 */
176#define put_short(s, w) { \
177 put_byte(s, (uch)((w) & 0xff)); \
178 put_byte(s, (uch)((ush)(w) >> 8)); \
179}
180
181/* ===========================================================================
182 * Send a value on a given number of bits.
183 * IN assertion: length <= 16 and value fits in length bits.
184 */
185#ifdef DEBUG
186local void send_bits OF((deflate_state *s, int value, int length));
187
188local void send_bits(deflate_state *s, int value, int length)
189{
190 Tracevv((stderr," l %2d v %4x ", length, value));
191 Assert(length > 0 && length <= 15, "invalid length");
192 s->bits_sent += (ulg)length;
193
194 /* If not enough room in bi_buf, use (valid) bits from bi_buf and
195 * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid))
196 * unused bits in value.
197 */
198 if (s->bi_valid > (int)Buf_size - length) {
199 s->bi_buf |= (ush)value << s->bi_valid;
200 put_short(s, s->bi_buf);
201 s->bi_buf = (ush)value >> (Buf_size - s->bi_valid);
202 s->bi_valid += length - Buf_size;
203 } else {
204 s->bi_buf |= (ush)value << s->bi_valid;
205 s->bi_valid += length;
206 }
207}
208#else /* !DEBUG */
209
210#define send_bits(s, value, length) \
211{ int len = length;\
212 if (s->bi_valid > (int)Buf_size - len) {\
213 int val = value;\
214 s->bi_buf |= (ush)val << s->bi_valid;\
215 put_short(s, s->bi_buf);\
216 s->bi_buf = (ush)val >> (Buf_size - s->bi_valid);\
217 s->bi_valid += len - Buf_size;\
218 } else {\
219 s->bi_buf |= (ush)(value) << s->bi_valid;\
220 s->bi_valid += len;\
221 }\
222}
223#endif /* DEBUG */
224
225
226/* the arguments must not have side effects */
227
228/* ===========================================================================
229 * Initialize the various 'constant' tables.
230 */
231local void tr_static_init(void)
232{
233#if defined(GEN_TREES_H) || !defined(STDC)
234 static int static_init_done = 0;
235 int n; /* iterates over tree elements */
236 int bits; /* bit counter */
237 int length; /* length value */
238 int codes; /* code value */
239 int dist; /* distance index */
240 ush bl_count[MAX_BITS+1];
241 /* number of codes at each bit length for an optimal tree */
242
243 if (static_init_done) return;
244
245 /* For some embedded targets, global variables are not initialized: */
246#ifdef NO_INIT_GLOBAL_POINTERS
247 static_l_desc.static_tree = static_ltree;
248 static_l_desc.extra_bits = extra_lbits;
249 static_d_desc.static_tree = static_dtree;
250 static_d_desc.extra_bits = extra_dbits;
251 static_bl_desc.extra_bits = extra_blbits;
252#endif
253
254 /* Initialize the mapping length (0..255) -> length code (0..28) */
255 length = 0;
256 for (codes = 0; codes < LENGTH_CODES-1; codes++) {
257 base_length[codes] = length;
258 for (n = 0; n < (1<<extra_lbits[codes]); n++) {
259 _length_code[length++] = (uch)codes;
260 }
261 }
262 Assert (length == 256, "tr_static_init: length != 256");
263 /* Note that the length 255 (match length 258) can be represented
264 * in two different ways: code 284 + 5 bits or code 285, so we
265 * overwrite length_code[255] to use the best encoding:
266 */
267 _length_code[length-1] = (uch)codes;
268
269 /* Initialize the mapping dist (0..32K) -> dist code (0..29) */
270 dist = 0;
271 for (codes = 0 ; codes < 16; codes++) {
272 base_dist[codes] = dist;
273 for (n = 0; n < (1<<extra_dbits[codes]); n++) {
274 _dist_code[dist++] = (uch)codes;
275 }
276 }
277 Assert (dist == 256, "tr_static_init: dist != 256");
278 dist >>= 7; /* from now on, all distances are divided by 128 */
279 for ( ; codes < D_CODES; codes++) {
280 base_dist[codes] = dist << 7;
281 for (n = 0; n < (1<<(extra_dbits[codes]-7)); n++) {
282 _dist_code[256 + dist++] = (uch)codes;
283 }
284 }
285 Assert (dist == 256, "tr_static_init: 256+dist != 512");
286
287 /* Construct the codes of the static literal tree */
288 for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0;
289 n = 0;
290 while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++;
291 while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++;
292 while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++;
293 while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++;
294 /* Codes 286 and 287 do not exist, but we must include them in the
295 * tree construction to get a canonical Huffman tree (longest code
296 * all ones)
297 */
298 gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count);
299
300 /* The static distance tree is trivial: */
301 for (n = 0; n < D_CODES; n++) {
302 static_dtree[n].Len = 5;
303 static_dtree[n].Code = bi_reverse((unsigned)n, 5);
304 }
305 static_init_done = 1;
306
307# ifdef GEN_TREES_H
308 gen_trees_header();
309# endif
310#endif /* defined(GEN_TREES_H) || !defined(STDC) */
311}
312
313/* ===========================================================================
314 * Genererate the file trees.h describing the static trees.
315 */
316#ifdef GEN_TREES_H
317# ifndef DEBUG
318# include <stdio.h>
319# endif
320
321# define SEPARATOR(i, last, width) \
322 ((i) == (last)? "\n};\n\n" : \
323 ((i) % (width) == (width)-1 ? ",\n" : ", "))
324
325void gen_trees_header(void)
326{
327 FILE *header = fopen("trees.h", "w");
328 int i;
329
330 Assert (header != NULL, "Can't open trees.h");
331 fprintf(header,
332 "/* header created automatically with -DGEN_TREES_H */\n\n");
333
334 fprintf(header, "local const ct_data static_ltree[L_CODES+2] = {\n");
335 for (i = 0; i < L_CODES+2; i++) {
336 fprintf(header, "{{%3u},{%3u}}%s", static_ltree[i].Code,
337 static_ltree[i].Len, SEPARATOR(i, L_CODES+1, 5));
338 }
339
340 fprintf(header, "local const ct_data static_dtree[D_CODES] = {\n");
341 for (i = 0; i < D_CODES; i++) {
342 fprintf(header, "{{%2u},{%2u}}%s", static_dtree[i].Code,
343 static_dtree[i].Len, SEPARATOR(i, D_CODES-1, 5));
344 }
345
346 fprintf(header, "const uch ZLIB_INTERNAL _dist_code[DIST_CODE_LEN] = {\n");
347 for (i = 0; i < DIST_CODE_LEN; i++) {
348 fprintf(header, "%2u%s", _dist_code[i],
349 SEPARATOR(i, DIST_CODE_LEN-1, 20));
350 }
351
352 fprintf(header,
353 "const uch ZLIB_INTERNAL _length_code[MAX_MATCH-MIN_MATCH+1]= {\n");
354 for (i = 0; i < MAX_MATCH-MIN_MATCH+1; i++) {
355 fprintf(header, "%2u%s", _length_code[i],
356 SEPARATOR(i, MAX_MATCH-MIN_MATCH, 20));
357 }
358
359 fprintf(header, "local const int base_length[LENGTH_CODES] = {\n");
360 for (i = 0; i < LENGTH_CODES; i++) {
361 fprintf(header, "%1u%s", base_length[i],
362 SEPARATOR(i, LENGTH_CODES-1, 20));
363 }
364
365 fprintf(header, "local const int base_dist[D_CODES] = {\n");
366 for (i = 0; i < D_CODES; i++) {
367 fprintf(header, "%5u%s", base_dist[i],
368 SEPARATOR(i, D_CODES-1, 10));
369 }
370
371 fclose(header);
372}
373#endif /* GEN_TREES_H */
374
375/* ===========================================================================
376 * Initialize the tree data structures for a new zlib stream.
377 */
378void ZLIB_INTERNAL _tr_init(deflate_state *s)
379{
380 tr_static_init();
381
382 s->l_desc.dyn_tree = s->dyn_ltree;
383 s->l_desc.stat_desc = &static_l_desc;
384
385 s->d_desc.dyn_tree = s->dyn_dtree;
386 s->d_desc.stat_desc = &static_d_desc;
387
388 s->bl_desc.dyn_tree = s->bl_tree;
389 s->bl_desc.stat_desc = &static_bl_desc;
390
391 s->bi_buf = 0;
392 s->bi_valid = 0;
393#ifdef DEBUG
394 s->compressed_len = 0L;
395 s->bits_sent = 0L;
396#endif
397
398 /* Initialize the first block of the first file: */
399 init_block(s);
400}
401
402/* ===========================================================================
403 * Initialize a new block.
404 */
405local void init_block(deflate_state *s)
406{
407 int n; /* iterates over tree elements */
408
409 /* Initialize the trees. */
410 for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0;
411 for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0;
412 for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0;
413
414 s->dyn_ltree[END_BLOCK].Freq = 1;
415 s->opt_len = s->static_len = 0L;
416 s->last_lit = s->matches = 0;
417}
418
419#define SMALLEST 1
420/* Index within the heap array of least frequent node in the Huffman tree */
421
422
423/* ===========================================================================
424 * Remove the smallest element from the heap and recreate the heap with
425 * one less element. Updates heap and heap_len.
426 */
427#define pqremove(s, tree, top) \
428{\
429 top = s->heap[SMALLEST]; \
430 s->heap[SMALLEST] = s->heap[s->heap_len--]; \
431 pqdownheap(s, tree, SMALLEST); \
432}
433
434/* ===========================================================================
435 * Compares to subtrees, using the tree depth as tie breaker when
436 * the subtrees have equal frequency. This minimizes the worst case length.
437 */
438#define smaller(tree, n, m, depth) \
439 (tree[n].Freq < tree[m].Freq || \
440 (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m]))
441
442/* ===========================================================================
443 * Restore the heap property by moving down the tree starting at node k,
444 * exchanging a node with the smallest of its two sons if necessary, stopping
445 * when the heap property is re-established (each father smaller than its
446 * two sons).
447 */
448local void pqdownheap(deflate_state *s, ct_data *tree, int k)
449{
450 int v = s->heap[k];
451 int j = k << 1; /* left son of k */
452 while (j <= s->heap_len) {
453 /* Set j to the smallest of the two sons: */
454 if (j < s->heap_len &&
455 smaller(tree, s->heap[j+1], s->heap[j], s->depth)) {
456 j++;
457 }
458 /* Exit if v is smaller than both sons */
459 if (smaller(tree, v, s->heap[j], s->depth)) break;
460
461 /* Exchange v with the smallest son */
462 s->heap[k] = s->heap[j]; k = j;
463
464 /* And continue down the tree, setting j to the left son of k */
465 j <<= 1;
466 }
467 s->heap[k] = v;
468}
469
470/* ===========================================================================
471 * Compute the optimal bit lengths for a tree and update the total bit length
472 * for the current block.
473 * IN assertion: the fields freq and dad are set, heap[heap_max] and
474 * above are the tree nodes sorted by increasing frequency.
475 * OUT assertions: the field len is set to the optimal bit length, the
476 * array bl_count contains the frequencies for each bit length.
477 * The length opt_len is updated; static_len is also updated if stree is
478 * not null.
479 */
480local void gen_bitlen(deflate_state *s, tree_desc *desc)
481{
482 ct_data *tree = desc->dyn_tree;
483 int max_code = desc->max_code;
484 const ct_data *stree = desc->stat_desc->static_tree;
485 const intf *extra = desc->stat_desc->extra_bits;
486 int base = desc->stat_desc->extra_base;
487 int max_length = desc->stat_desc->max_length;
488 int h; /* heap index */
489 int n, m; /* iterate over the tree elements */
490 int bits; /* bit length */
491 int xbits; /* extra bits */
492 ush f; /* frequency */
493 int overflow = 0; /* number of elements with bit length too large */
494
495 for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0;
496
497 /* In a first pass, compute the optimal bit lengths (which may
498 * overflow in the case of the bit length tree).
499 */
500 tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */
501
502 for (h = s->heap_max+1; h < HEAP_SIZE; h++) {
503 n = s->heap[h];
504 bits = tree[tree[n].Dad].Len + 1;
505 if (bits > max_length) bits = max_length, overflow++;
506 tree[n].Len = (ush)bits;
507 /* We overwrite tree[n].Dad which is no longer needed */
508
509 if (n > max_code) continue; /* not a leaf node */
510
511 s->bl_count[bits]++;
512 xbits = 0;
513 if (n >= base) xbits = extra[n-base];
514 f = tree[n].Freq;
515 s->opt_len += (ulg)f * (bits + xbits);
516 if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits);
517 }
518 if (overflow == 0) return;
519
520 Trace((stderr,"\nbit length overflow\n"));
521 /* This happens for example on obj2 and pic of the Calgary corpus */
522
523 /* Find the first bit length which could increase: */
524 do {
525 bits = max_length-1;
526 while (s->bl_count[bits] == 0) bits--;
527 s->bl_count[bits]--; /* move one leaf down the tree */
528 s->bl_count[bits+1] += 2; /* move one overflow item as its brother */
529 s->bl_count[max_length]--;
530 /* The brother of the overflow item also moves one step up,
531 * but this does not affect bl_count[max_length]
532 */
533 overflow -= 2;
534 } while (overflow > 0);
535
536 /* Now recompute all bit lengths, scanning in increasing frequency.
537 * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all
538 * lengths instead of fixing only the wrong ones. This idea is taken
539 * from 'ar' written by Haruhiko Okumura.)
540 */
541 for (bits = max_length; bits != 0; bits--) {
542 n = s->bl_count[bits];
543 while (n != 0) {
544 m = s->heap[--h];
545 if (m > max_code) continue;
546 if ((unsigned) tree[m].Len != (unsigned) bits) {
547 Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits));
548 s->opt_len += ((long)bits - (long)tree[m].Len)
549 *(long)tree[m].Freq;
550 tree[m].Len = (ush)bits;
551 }
552 n--;
553 }
554 }
555}
556
557/* ===========================================================================
558 * Generate the codes for a given tree and bit counts (which need not be
559 * optimal).
560 * IN assertion: the array bl_count contains the bit length statistics for
561 * the given tree and the field len is set for all tree elements.
562 * OUT assertion: the field code is set for all tree elements of non
563 * zero code length.
564 */
565local void gen_codes (ct_data *tree, int max_code, ushf *bl_count)
566{
567 ush next_code[MAX_BITS+1]; /* next code value for each bit length */
568 ush codes = 0; /* running code value */
569 int bits; /* bit index */
570 int n; /* code index */
571
572 /* The distribution counts are first used to generate the code values
573 * without bit reversal.
574 */
575 for (bits = 1; bits <= MAX_BITS; bits++) {
576 next_code[bits] = codes = (codes + bl_count[bits-1]) << 1;
577 }
578 /* Check that the bit counts in bl_count are consistent. The last code
579 * must be all ones.
580 */
581 Assert (codes + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1,
582 "inconsistent bit counts");
583 Tracev((stderr,"\ngen_codes: max_code %d ", max_code));
584
585 for (n = 0; n <= max_code; n++) {
586 int len = tree[n].Len;
587 if (len == 0) continue;
588 /* Now reverse the bits */
589 tree[n].Code = bi_reverse(next_code[len]++, len);
590
591 Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ",
592 n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1));
593 }
594}
595
596/* ===========================================================================
597 * Construct one Huffman tree and assigns the code bit strings and lengths.
598 * Update the total bit length for the current block.
599 * IN assertion: the field freq is set for all tree elements.
600 * OUT assertions: the fields len and code are set to the optimal bit length
601 * and corresponding code. The length opt_len is updated; static_len is
602 * also updated if stree is not null. The field max_code is set.
603 */
604local void build_tree(deflate_state *s, tree_desc *desc)
605{
606 ct_data *tree = desc->dyn_tree;
607 const ct_data *stree = desc->stat_desc->static_tree;
608 int elems = desc->stat_desc->elems;
609 int n, m; /* iterate over heap elements */
610 int max_code = -1; /* largest code with non zero frequency */
611 int node; /* new node being created */
612
613 /* Construct the initial heap, with least frequent element in
614 * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1].
615 * heap[0] is not used.
616 */
617 s->heap_len = 0, s->heap_max = HEAP_SIZE;
618
619 for (n = 0; n < elems; n++) {
620 if (tree[n].Freq != 0) {
621 s->heap[++(s->heap_len)] = max_code = n;
622 s->depth[n] = 0;
623 } else {
624 tree[n].Len = 0;
625 }
626 }
627
628 /* The pkzip format requires that at least one distance code exists,
629 * and that at least one bit should be sent even if there is only one
630 * possible code. So to avoid special checks later on we force at least
631 * two codes of non zero frequency.
632 */
633 while (s->heap_len < 2) {
634 node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0);
635 tree[node].Freq = 1;
636 s->depth[node] = 0;
637 s->opt_len--; if (stree) s->static_len -= stree[node].Len;
638 /* node is 0 or 1 so it does not have extra bits */
639 }
640 desc->max_code = max_code;
641
642 /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree,
643 * establish sub-heaps of increasing lengths:
644 */
645 for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, n);
646
647 /* Construct the Huffman tree by repeatedly combining the least two
648 * frequent nodes.
649 */
650 node = elems; /* next internal node of the tree */
651 do {
652 pqremove(s, tree, n); /* n = node of least frequency */
653 m = s->heap[SMALLEST]; /* m = node of next least frequency */
654
655 s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */
656 s->heap[--(s->heap_max)] = m;
657
658 /* Create a new node father of n and m */
659 tree[node].Freq = tree[n].Freq + tree[m].Freq;
660 s->depth[node] = (uch)((s->depth[n] >= s->depth[m] ?
661 s->depth[n] : s->depth[m]) + 1);
662 tree[n].Dad = tree[m].Dad = (ush)node;
663#ifdef DUMP_BL_TREE
664 if (tree == s->bl_tree) {
665 fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)",
666 node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq);
667 }
668#endif
669 /* and insert the new node in the heap */
670 s->heap[SMALLEST] = node++;
671 pqdownheap(s, tree, SMALLEST);
672
673 } while (s->heap_len >= 2);
674
675 s->heap[--(s->heap_max)] = s->heap[SMALLEST];
676
677 /* At this point, the fields freq and dad are set. We can now
678 * generate the bit lengths.
679 */
680 gen_bitlen(s, (tree_desc *)desc);
681
682 /* The field len is now set, we can generate the bit codes */
683 gen_codes ((ct_data *)tree, max_code, s->bl_count);
684}
685
686/* ===========================================================================
687 * Scan a literal or distance tree to determine the frequencies of the codes
688 * in the bit length tree.
689 */
690local void scan_tree (deflate_state *s, ct_data *tree, int max_code)
691{
692 int n; /* iterates over all tree elements */
693 int prevlen = -1; /* last emitted length */
694 int curlen; /* length of current code */
695 int nextlen = tree[0].Len; /* length of next code */
696 int count = 0; /* repeat count of the current code */
697 int max_count = 7; /* max repeat count */
698 int min_count = 4; /* min repeat count */
699
700 if (nextlen == 0) max_count = 138, min_count = 3;
701 tree[max_code+1].Len = (ush)0xffff; /* guard */
702
703 for (n = 0; n <= max_code; n++) {
704 curlen = nextlen; nextlen = tree[n+1].Len;
705 if (++count < max_count && curlen == nextlen) {
706 continue;
707 } else if (count < min_count) {
708 s->bl_tree[curlen].Freq += count;
709 } else if (curlen != 0) {
710 if (curlen != prevlen) s->bl_tree[curlen].Freq++;
711 s->bl_tree[REP_3_6].Freq++;
712 } else if (count <= 10) {
713 s->bl_tree[REPZ_3_10].Freq++;
714 } else {
715 s->bl_tree[REPZ_11_138].Freq++;
716 }
717 count = 0; prevlen = curlen;
718 if (nextlen == 0) {
719 max_count = 138, min_count = 3;
720 } else if (curlen == nextlen) {
721 max_count = 6, min_count = 3;
722 } else {
723 max_count = 7, min_count = 4;
724 }
725 }
726}
727
728/* ===========================================================================
729 * Send a literal or distance tree in compressed form, using the codes in
730 * bl_tree.
731 */
732local void send_tree (deflate_state *s, ct_data *tree, int max_code)
733{
734 int n; /* iterates over all tree elements */
735 int prevlen = -1; /* last emitted length */
736 int curlen; /* length of current code */
737 int nextlen = tree[0].Len; /* length of next code */
738 int count = 0; /* repeat count of the current code */
739 int max_count = 7; /* max repeat count */
740 int min_count = 4; /* min repeat count */
741
742 /* tree[max_code+1].Len = -1; */ /* guard already set */
743 if (nextlen == 0) max_count = 138, min_count = 3;
744
745 for (n = 0; n <= max_code; n++) {
746 curlen = nextlen; nextlen = tree[n+1].Len;
747 if (++count < max_count && curlen == nextlen) {
748 continue;
749 } else if (count < min_count) {
750 do { send_code(s, curlen, s->bl_tree); } while (--count != 0);
751
752 } else if (curlen != 0) {
753 if (curlen != prevlen) {
754 send_code(s, curlen, s->bl_tree); count--;
755 }
756 Assert(count >= 3 && count <= 6, " 3_6?");
757 send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2);
758
759 } else if (count <= 10) {
760 send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3);
761
762 } else {
763 send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7);
764 }
765 count = 0; prevlen = curlen;
766 if (nextlen == 0) {
767 max_count = 138, min_count = 3;
768 } else if (curlen == nextlen) {
769 max_count = 6, min_count = 3;
770 } else {
771 max_count = 7, min_count = 4;
772 }
773 }
774}
775
776/* ===========================================================================
777 * Construct the Huffman tree for the bit lengths and return the index in
778 * bl_order of the last bit length code to send.
779 */
780local int build_bl_tree(deflate_state *s)
781{
782 int max_blindex; /* index of last bit length code of non zero freq */
783
784 /* Determine the bit length frequencies for literal and distance trees */
785 scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code);
786 scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code);
787
788 /* Build the bit length tree: */
789 build_tree(s, (tree_desc *)(&(s->bl_desc)));
790 /* opt_len now includes the length of the tree representations, except
791 * the lengths of the bit lengths codes and the 5+5+4 bits for the counts.
792 */
793
794 /* Determine the number of bit length codes to send. The pkzip format
795 * requires that at least 4 bit length codes be sent. (appnote.txt says
796 * 3 but the actual value used is 4.)
797 */
798 for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) {
799 if (s->bl_tree[bl_order[max_blindex]].Len != 0) break;
800 }
801 /* Update opt_len to include the bit length tree and counts */
802 s->opt_len += 3*(max_blindex+1) + 5+5+4;
803 Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld",
804 s->opt_len, s->static_len));
805
806 return max_blindex;
807}
808
809/* ===========================================================================
810 * Send the header for a block using dynamic Huffman trees: the counts, the
811 * lengths of the bit length codes, the literal tree and the distance tree.
812 * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.
813 */
814local void send_all_trees(deflate_state *s, int lcodes, int dcodes, int blcodes)
815{
816 int rank; /* index in bl_order */
817
818 Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes");
819 Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES,
820 "too many codes");
821 Tracev((stderr, "\nbl counts: "));
822 send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */
823 send_bits(s, dcodes-1, 5);
824 send_bits(s, blcodes-4, 4); /* not -3 as stated in appnote.txt */
825 for (rank = 0; rank < blcodes; rank++) {
826 Tracev((stderr, "\nbl code %2d ", bl_order[rank]));
827 send_bits(s, s->bl_tree[bl_order[rank]].Len, 3);
828 }
829 Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent));
830
831 send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */
832 Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent));
833
834 send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */
835 Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent));
836}
837
838/* ===========================================================================
839 * Send a stored block
840 */
841void ZLIB_INTERNAL _tr_stored_block(deflate_state *s, charf *buf, ulg stored_len, int last)
842{
843 send_bits(s, (STORED_BLOCK<<1)+last, 3); /* send block type */
844#ifdef DEBUG
845 s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L;
846 s->compressed_len += (stored_len + 4) << 3;
847#endif
848 copy_block(s, buf, (unsigned)stored_len, 1); /* with header */
849}
850
851/* ===========================================================================
852 * Flush the bits in the bit buffer to pending output (leaves at most 7 bits)
853 */
854void ZLIB_INTERNAL _tr_flush_bits(deflate_state *s)
855{
856 bi_flush(s);
857}
858
859/* ===========================================================================
860 * Send one empty static block to give enough lookahead for inflate.
861 * This takes 10 bits, of which 7 may remain in the bit buffer.
862 */
863void ZLIB_INTERNAL _tr_align(deflate_state *s)
864{
865 send_bits(s, STATIC_TREES<<1, 3);
866 send_code(s, END_BLOCK, static_ltree);
867#ifdef DEBUG
868 s->compressed_len += 10L; /* 3 for block type, 7 for EOB */
869#endif
870 bi_flush(s);
871}
872
873/* ===========================================================================
874 * Determine the best encoding for the current block: dynamic trees, static
875 * trees or store, and output the encoded block to the zip file.
876 */
877void ZLIB_INTERNAL _tr_flush_block(deflate_state *s, charf *buf, ulg stored_len, int last)
878{
879 ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */
880 int max_blindex = 0; /* index of last bit length code of non zero freq */
881
882 /* Build the Huffman trees unless a stored block is forced */
883 if (s->level > 0) {
884
885 /* Check if the file is binary or text */
886 if (s->strm->data_type == Z_UNKNOWN)
887 s->strm->data_type = detect_data_type(s);
888
889 /* Construct the literal and distance trees */
890 build_tree(s, (tree_desc *)(&(s->l_desc)));
891 Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len,
892 s->static_len));
893
894 build_tree(s, (tree_desc *)(&(s->d_desc)));
895 Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len,
896 s->static_len));
897 /* At this point, opt_len and static_len are the total bit lengths of
898 * the compressed block data, excluding the tree representations.
899 */
900
901 /* Build the bit length tree for the above two trees, and get the index
902 * in bl_order of the last bit length code to send.
903 */
904 max_blindex = build_bl_tree(s);
905
906 /* Determine the best encoding. Compute the block lengths in bytes. */
907 opt_lenb = (s->opt_len+3+7)>>3;
908 static_lenb = (s->static_len+3+7)>>3;
909
910 Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ",
911 opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len,
912 s->last_lit));
913
914 if (static_lenb <= opt_lenb) opt_lenb = static_lenb;
915
916 } else {
917 Assert(buf != (char*)0, "lost buf");
918 opt_lenb = static_lenb = stored_len + 5; /* force a stored block */
919 }
920
921#ifdef FORCE_STORED
922 if (buf != (char*)0) { /* force stored block */
923#else
924 if (stored_len+4 <= opt_lenb && buf != (char*)0) {
925 /* 4: two words for the lengths */
926#endif
927 /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.
928 * Otherwise we can't have processed more than WSIZE input bytes since
929 * the last block flush, because compression would have been
930 * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to
931 * transform a block into a stored block.
932 */
933 _tr_stored_block(s, buf, stored_len, last);
934
935#ifdef FORCE_STATIC
936 } else if (static_lenb >= 0) { /* force static trees */
937#else
938 } else if (s->strategy == Z_FIXED || static_lenb == opt_lenb) {
939#endif
940 send_bits(s, (STATIC_TREES<<1)+last, 3);
941 compress_block(s, (const ct_data *)static_ltree,
942 (const ct_data *)static_dtree);
943#ifdef DEBUG
944 s->compressed_len += 3 + s->static_len;
945#endif
946 } else {
947 send_bits(s, (DYN_TREES<<1)+last, 3);
948 send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1,
949 max_blindex+1);
950 compress_block(s, (const ct_data *)s->dyn_ltree,
951 (const ct_data *)s->dyn_dtree);
952#ifdef DEBUG
953 s->compressed_len += 3 + s->opt_len;
954#endif
955 }
956 Assert (s->compressed_len == s->bits_sent, "bad compressed size");
957 /* The above check is made mod 2^32, for files larger than 512 MB
958 * and uLong implemented on 32 bits.
959 */
960 init_block(s);
961
962 if (last) {
963 bi_windup(s);
964#ifdef DEBUG
965 s->compressed_len += 7; /* align on byte boundary */
966#endif
967 }
968 Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3,
969 s->compressed_len-7*last));
970 }
971
972 /* ===========================================================================
973 * Save the match info and tally the frequency counts. Return true if
974 * the current block must be flushed.
975 */
976 int ZLIB_INTERNAL _tr_tally (deflate_state *s, unsigned dist, unsigned lc)
977 {
978 s->d_buf[s->last_lit] = (ush)dist;
979 s->l_buf[s->last_lit++] = (uch)lc;
980 if (dist == 0) {
981 /* lc is the unmatched char */
982 s->dyn_ltree[lc].Freq++;
983 } else {
984 s->matches++;
985 /* Here, lc is the match length - MIN_MATCH */
986 dist--; /* dist = match distance - 1 */
987 Assert((ush)dist < (ush)MAX_DIST(s) &&
988 (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) &&
989 (ush)d_code(dist) < (ush)D_CODES, "_tr_tally: bad match");
990
991 s->dyn_ltree[_length_code[lc]+LITERALS+1].Freq++;
992 s->dyn_dtree[d_code(dist)].Freq++;
993 }
994
995#ifdef TRUNCATE_BLOCK
996 /* Try to guess if it is profitable to stop the current block here */
997 if ((s->last_lit & 0x1fff) == 0 && s->level > 2) {
998 /* Compute an upper bound for the compressed length */
999 ulg out_length = (ulg)s->last_lit*8L;
1000 ulg in_length = (ulg)((long)s->strstart - s->block_start);
1001 int dcode;
1002 for (dcode = 0; dcode < D_CODES; dcode++) {
1003 out_length += (ulg)s->dyn_dtree[dcode].Freq *
1004 (5L+extra_dbits[dcode]);
1005 }
1006 out_length >>= 3;
1007 Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ",
1008 s->last_lit, in_length, out_length,
1009 100L - out_length*100L/in_length));
1010 if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1;
1011 }
1012#endif
1013 return (s->last_lit == s->lit_bufsize-1);
1014 /* We avoid equality with lit_bufsize because of wraparound at 64K
1015 * on 16 bit machines and because stored blocks are restricted to
1016 * 64K-1 bytes.
1017 */
1018 }
1019
1020 /* ===========================================================================
1021 * Send the block data compressed using the given Huffman trees
1022 */
1023 local void compress_block(deflate_state *s, const ct_data *ltree, const ct_data *dtree)
1024 {
1025 unsigned dist; /* distance of matched string */
1026 int lc; /* match length or unmatched char (if dist == 0) */
1027 unsigned lx = 0; /* running index in l_buf */
1028 unsigned codes; /* the code to send */
1029 int extra; /* number of extra bits to send */
1030
1031 if (s->last_lit != 0) do {
1032 dist = s->d_buf[lx];
1033 lc = s->l_buf[lx++];
1034 if (dist == 0) {
1035 send_code(s, lc, ltree); /* send a literal byte */
1036 Tracecv(isgraph(lc), (stderr," '%c' ", lc));
1037 } else {
1038 /* Here, lc is the match length - MIN_MATCH */
1039 codes = _length_code[lc];
1040 send_code(s, codes + LITERALS+1, ltree); /* send the length code */
1041 extra = extra_lbits[codes];
1042 if (extra != 0) {
1043 lc -= base_length[codes];
1044 send_bits(s, lc, extra); /* send the extra length bits */
1045 }
1046 dist--; /* dist is now the match distance - 1 */
1047 codes = d_code(dist);
1048 Assert (codes < D_CODES, "bad d_code");
1049
1050 send_code(s, codes, dtree); /* send the distance code */
1051 extra = extra_dbits[codes];
1052 if (extra != 0) {
1053 dist -= base_dist[codes];
1054 send_bits(s, dist, extra); /* send the extra distance bits */
1055 }
1056 } /* literal or match pair ? */
1057
1058 /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */
1059 Assert((uInt)(s->pending) < s->lit_bufsize + 2*lx,
1060 "pendingBuf overflow");
1061
1062 } while (lx < s->last_lit);
1063
1064 send_code(s, END_BLOCK, ltree);
1065 }
1066
1067 /* ===========================================================================
1068 * Check if the data type is TEXT or BINARY, using the following algorithm:
1069 * - TEXT if the two conditions below are satisfied:
1070 * a) There are no non-portable control characters belonging to the
1071 * "black list" (0..6, 14..25, 28..31).
1072 * b) There is at least one printable character belonging to the
1073 * "white list" (9 {TAB}, 10 {LF}, 13 {CR}, 32..255).
1074 * - BINARY otherwise.
1075 * - The following partially-portable control characters form a
1076 * "gray list" that is ignored in this detection algorithm:
1077 * (7 {BEL}, 8 {BS}, 11 {VT}, 12 {FF}, 26 {SUB}, 27 {ESC}).
1078 * IN assertion: the fields Freq of dyn_ltree are set.
1079 */
1080 local int detect_data_type(deflate_state *s)
1081 {
1082 /* black_mask is the bit mask of black-listed bytes
1083 * set bits 0..6, 14..25, and 28..31
1084 * 0xf3ffc07f = binary 11110011111111111100000001111111
1085 */
1086 unsigned long black_mask = 0xf3ffc07fUL;
1087 int n;
1088
1089 /* Check for non-textual ("black-listed") bytes. */
1090 for (n = 0; n <= 31; n++, black_mask >>= 1)
1091 if ((black_mask & 1) && (s->dyn_ltree[n].Freq != 0))
1092 return Z_BINARY;
1093
1094 /* Check for textual ("white-listed") bytes. */
1095 if (s->dyn_ltree[9].Freq != 0 || s->dyn_ltree[10].Freq != 0
1096 || s->dyn_ltree[13].Freq != 0)
1097 return Z_TEXT;
1098 for (n = 32; n < LITERALS; n++)
1099 if (s->dyn_ltree[n].Freq != 0)
1100 return Z_TEXT;
1101
1102 /* There are no "black-listed" or "white-listed" bytes:
1103 * this stream either is empty or has tolerated ("gray-listed") bytes only.
1104 */
1105 return Z_BINARY;
1106 }
1107
1108 /* ===========================================================================
1109 * Reverse the first len bits of a code, using straightforward code (a faster
1110 * method would use a table)
1111 * IN assertion: 1 <= len <= 15
1112 */
1113 local unsigned bi_reverse(unsigned codes, int len)
1114 {
1115 register unsigned res = 0;
1116 do {
1117 res |= codes & 1;
1118 codes >>= 1, res <<= 1;
1119 } while (--len > 0);
1120 return res >> 1;
1121 }
1122
1123 /* ===========================================================================
1124 * Flush the bit buffer, keeping at most 7 bits in it.
1125 */
1126 local void bi_flush(deflate_state *s)
1127 {
1128 if (s->bi_valid == 16) {
1129 put_short(s, s->bi_buf);
1130 s->bi_buf = 0;
1131 s->bi_valid = 0;
1132 } else if (s->bi_valid >= 8) {
1133 put_byte(s, (Byte)s->bi_buf);
1134 s->bi_buf >>= 8;
1135 s->bi_valid -= 8;
1136 }
1137 }
1138
1139 /* ===========================================================================
1140 * Flush the bit buffer and align the output on a byte boundary
1141 */
1142 local void bi_windup(deflate_state *s)
1143 {
1144 if (s->bi_valid > 8) {
1145 put_short(s, s->bi_buf);
1146 } else if (s->bi_valid > 0) {
1147 put_byte(s, (Byte)s->bi_buf);
1148 }
1149 s->bi_buf = 0;
1150 s->bi_valid = 0;
1151#ifdef DEBUG
1152 s->bits_sent = (s->bits_sent+7) & ~7;
1153#endif
1154 }
1155
1156 /* ===========================================================================
1157 * Copy a stored block, storing first the length and its
1158 * one's complement if requested.
1159 */
1160 local void copy_block(deflate_state *s, charf *buf, unsigned len, int header)
1161 {
1162 bi_windup(s); /* align on byte boundary */
1163
1164 if (header) {
1165 put_short(s, (ush)len);
1166 put_short(s, (ush)~len);
1167#ifdef DEBUG
1168 s->bits_sent += 2*16;
1169#endif
1170 }
1171#ifdef DEBUG
1172 s->bits_sent += (ulg)len<<3;
1173#endif
1174 while (len--) {
1175 put_byte(s, *buf++);
1176 }
1177 }