fix 'hf iclass snoop'
[proxmark3-svn] / zlib / trees.c
CommitLineData
f3919878 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
8e074056 35//-----------------------------------------------------------------------------
36// This version of zlib is modified for use within the Proxmark3 project.
37// Files from the original distribution which are not required for this
38// purpose are not included. All modifications can easily be found
39// by searching for #ifdef ZLIB_PM3_TUNED and #ifndef ZLIB_PM3_TUNED.
40//-----------------------------------------------------------------------------
41
f3919878 42/* #define GEN_TREES_H */
43
8e074056 44
f3919878 45#include "deflate.h"
46
47#ifdef DEBUG
48# include <ctype.h>
49#endif
50
51/* ===========================================================================
52 * Constants
53 */
54
55#define MAX_BL_BITS 7
56/* Bit length codes must not exceed MAX_BL_BITS bits */
57
58#define END_BLOCK 256
59/* end of block literal code */
60
61#define REP_3_6 16
62/* repeat previous bit length 3-6 times (2 bits of repeat count) */
63
64#define REPZ_3_10 17
65/* repeat a zero length 3-10 times (3 bits of repeat count) */
66
67#define REPZ_11_138 18
68/* repeat a zero length 11-138 times (7 bits of repeat count) */
69
70local const int extra_lbits[LENGTH_CODES] /* extra bits for each length code */
71 = {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};
72
73local const int extra_dbits[D_CODES] /* extra bits for each distance code */
74 = {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};
75
76local const int extra_blbits[BL_CODES]/* extra bits for each bit length code */
77 = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7};
78
79local const uch bl_order[BL_CODES]
80 = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15};
81/* The lengths of the bit length codes are sent in order of decreasing
82 * probability, to avoid transmitting the lengths for unused bit length codes.
83 */
84
85/* ===========================================================================
86 * Local data. These are initialized only once.
87 */
88
89#define DIST_CODE_LEN 512 /* see definition of array dist_code below */
90
91#if defined(GEN_TREES_H) || !defined(STDC)
92/* non ANSI compilers may not accept trees.h */
93
94local ct_data static_ltree[L_CODES+2];
95/* The static literal tree. Since the bit lengths are imposed, there is no
96 * need for the L_CODES extra codes used during heap construction. However
97 * The codes 286 and 287 are needed to build a canonical tree (see _tr_init
98 * below).
99 */
100
101local ct_data static_dtree[D_CODES];
102/* The static distance tree. (Actually a trivial tree since all codes use
103 * 5 bits.)
104 */
105
106uch _dist_code[DIST_CODE_LEN];
107/* Distance codes. The first 256 values correspond to the distances
108 * 3 .. 258, the last 256 values correspond to the top 8 bits of
109 * the 15 bit distances.
110 */
111
112uch _length_code[MAX_MATCH-MIN_MATCH+1];
113/* length code for each normalized match length (0 == MIN_MATCH) */
114
115local int base_length[LENGTH_CODES];
116/* First normalized length for each code (0 = MIN_MATCH) */
117
118local int base_dist[D_CODES];
119/* First normalized distance for each code (0 = distance of 1) */
120
121#else
122# include "trees.h"
123#endif /* GEN_TREES_H */
124
125struct static_tree_desc_s {
126 const ct_data *static_tree; /* static tree or NULL */
127 const intf *extra_bits; /* extra bits for each code or NULL */
128 int extra_base; /* base index for extra_bits */
129 int elems; /* max number of elements in the tree */
130 int max_length; /* max bit length for the codes */
131};
132
133local static_tree_desc static_l_desc =
134{static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS};
135
136local static_tree_desc static_d_desc =
137{static_dtree, extra_dbits, 0, D_CODES, MAX_BITS};
138
139local static_tree_desc static_bl_desc =
140{(const ct_data *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS};
141
142/* ===========================================================================
143 * Local (static) routines in this file.
144 */
145
146local void tr_static_init OF((void));
147local void init_block OF((deflate_state *s));
148local void pqdownheap OF((deflate_state *s, ct_data *tree, int k));
149local void gen_bitlen OF((deflate_state *s, tree_desc *desc));
150local void gen_codes OF((ct_data *tree, int max_code, ushf *bl_count));
151local void build_tree OF((deflate_state *s, tree_desc *desc));
152local void scan_tree OF((deflate_state *s, ct_data *tree, int max_code));
153local void send_tree OF((deflate_state *s, ct_data *tree, int max_code));
154local int build_bl_tree OF((deflate_state *s));
155local void send_all_trees OF((deflate_state *s, int lcodes, int dcodes,
156 int blcodes));
157local void compress_block OF((deflate_state *s, const ct_data *ltree,
158 const ct_data *dtree));
159local int detect_data_type OF((deflate_state *s));
160local unsigned bi_reverse OF((unsigned value, int length));
161local void bi_windup OF((deflate_state *s));
162local void bi_flush OF((deflate_state *s));
163local void copy_block OF((deflate_state *s, charf *buf, unsigned len,
164 int header));
165
166#ifdef GEN_TREES_H
167local void gen_trees_header OF((void));
168#endif
169
170#ifndef DEBUG
171# define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len)
172 /* Send a code of the given tree. c and tree must not have side effects */
173
174#else /* DEBUG */
175# define send_code(s, c, tree) \
176 { if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \
177 send_bits(s, tree[c].Code, tree[c].Len); }
178#endif
179
180/* ===========================================================================
181 * Output a short LSB first on the stream.
182 * IN assertion: there is enough room in pendingBuf.
183 */
184#define put_short(s, w) { \
185 put_byte(s, (uch)((w) & 0xff)); \
186 put_byte(s, (uch)((ush)(w) >> 8)); \
187}
188
189/* ===========================================================================
190 * Send a value on a given number of bits.
191 * IN assertion: length <= 16 and value fits in length bits.
192 */
193#ifdef DEBUG
194local void send_bits OF((deflate_state *s, int value, int length));
195
196local void send_bits(s, value, length)
197 deflate_state *s;
198 int value; /* value to send */
199 int length; /* number of bits */
200{
201 Tracevv((stderr," l %2d v %4x ", length, value));
202 Assert(length > 0 && length <= 15, "invalid length");
203 s->bits_sent += (ulg)length;
204
205 /* If not enough room in bi_buf, use (valid) bits from bi_buf and
206 * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid))
207 * unused bits in value.
208 */
209 if (s->bi_valid > (int)Buf_size - length) {
210 s->bi_buf |= (ush)value << s->bi_valid;
211 put_short(s, s->bi_buf);
212 s->bi_buf = (ush)value >> (Buf_size - s->bi_valid);
213 s->bi_valid += length - Buf_size;
214 } else {
215 s->bi_buf |= (ush)value << s->bi_valid;
216 s->bi_valid += length;
217 }
218}
219#else /* !DEBUG */
220
221#define send_bits(s, value, length) \
222{ int len = length;\
223 if (s->bi_valid > (int)Buf_size - len) {\
224 int val = value;\
225 s->bi_buf |= (ush)val << s->bi_valid;\
226 put_short(s, s->bi_buf);\
227 s->bi_buf = (ush)val >> (Buf_size - s->bi_valid);\
228 s->bi_valid += len - Buf_size;\
229 } else {\
230 s->bi_buf |= (ush)(value) << s->bi_valid;\
231 s->bi_valid += len;\
232 }\
233}
234#endif /* DEBUG */
235
236
237/* the arguments must not have side effects */
238
239/* ===========================================================================
240 * Initialize the various 'constant' tables.
241 */
242local void tr_static_init()
243{
244#if defined(GEN_TREES_H) || !defined(STDC)
245 static int static_init_done = 0;
246 int n; /* iterates over tree elements */
247 int bits; /* bit counter */
248 int length; /* length value */
249 int code; /* code value */
250 int dist; /* distance index */
251 ush bl_count[MAX_BITS+1];
252 /* number of codes at each bit length for an optimal tree */
253
254 if (static_init_done) return;
255
256 /* For some embedded targets, global variables are not initialized: */
257#ifdef NO_INIT_GLOBAL_POINTERS
258 static_l_desc.static_tree = static_ltree;
259 static_l_desc.extra_bits = extra_lbits;
260 static_d_desc.static_tree = static_dtree;
261 static_d_desc.extra_bits = extra_dbits;
262 static_bl_desc.extra_bits = extra_blbits;
263#endif
264
265 /* Initialize the mapping length (0..255) -> length code (0..28) */
266 length = 0;
267 for (code = 0; code < LENGTH_CODES-1; code++) {
268 base_length[code] = length;
269 for (n = 0; n < (1<<extra_lbits[code]); n++) {
270 _length_code[length++] = (uch)code;
271 }
272 }
273 Assert (length == 256, "tr_static_init: length != 256");
274 /* Note that the length 255 (match length 258) can be represented
275 * in two different ways: code 284 + 5 bits or code 285, so we
276 * overwrite length_code[255] to use the best encoding:
277 */
278 _length_code[length-1] = (uch)code;
279
280 /* Initialize the mapping dist (0..32K) -> dist code (0..29) */
281 dist = 0;
282 for (code = 0 ; code < 16; code++) {
283 base_dist[code] = dist;
284 for (n = 0; n < (1<<extra_dbits[code]); n++) {
285 _dist_code[dist++] = (uch)code;
286 }
287 }
288 Assert (dist == 256, "tr_static_init: dist != 256");
289 dist >>= 7; /* from now on, all distances are divided by 128 */
290 for ( ; code < D_CODES; code++) {
291 base_dist[code] = dist << 7;
292 for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) {
293 _dist_code[256 + dist++] = (uch)code;
294 }
295 }
296 Assert (dist == 256, "tr_static_init: 256+dist != 512");
297
298 /* Construct the codes of the static literal tree */
299 for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0;
300 n = 0;
301 while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++;
302 while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++;
303 while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++;
304 while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++;
305 /* Codes 286 and 287 do not exist, but we must include them in the
306 * tree construction to get a canonical Huffman tree (longest code
307 * all ones)
308 */
309 gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count);
310
311 /* The static distance tree is trivial: */
312 for (n = 0; n < D_CODES; n++) {
313 static_dtree[n].Len = 5;
314 static_dtree[n].Code = bi_reverse((unsigned)n, 5);
315 }
316 static_init_done = 1;
317
318# ifdef GEN_TREES_H
319 gen_trees_header();
320# endif
321#endif /* defined(GEN_TREES_H) || !defined(STDC) */
322}
323
324/* ===========================================================================
325 * Genererate the file trees.h describing the static trees.
326 */
327#ifdef GEN_TREES_H
328# ifndef DEBUG
329# include <stdio.h>
330# endif
331
332# define SEPARATOR(i, last, width) \
333 ((i) == (last)? "\n};\n\n" : \
334 ((i) % (width) == (width)-1 ? ",\n" : ", "))
335
336void gen_trees_header()
337{
338 FILE *header = fopen("trees.h", "w");
339 int i;
340
341 Assert (header != NULL, "Can't open trees.h");
342 fprintf(header,
343 "/* header created automatically with -DGEN_TREES_H */\n\n");
344
345 fprintf(header, "local const ct_data static_ltree[L_CODES+2] = {\n");
346 for (i = 0; i < L_CODES+2; i++) {
347 fprintf(header, "{{%3u},{%3u}}%s", static_ltree[i].Code,
348 static_ltree[i].Len, SEPARATOR(i, L_CODES+1, 5));
349 }
350
351 fprintf(header, "local const ct_data static_dtree[D_CODES] = {\n");
352 for (i = 0; i < D_CODES; i++) {
353 fprintf(header, "{{%2u},{%2u}}%s", static_dtree[i].Code,
354 static_dtree[i].Len, SEPARATOR(i, D_CODES-1, 5));
355 }
356
357 fprintf(header, "const uch ZLIB_INTERNAL _dist_code[DIST_CODE_LEN] = {\n");
358 for (i = 0; i < DIST_CODE_LEN; i++) {
359 fprintf(header, "%2u%s", _dist_code[i],
360 SEPARATOR(i, DIST_CODE_LEN-1, 20));
361 }
362
363 fprintf(header,
364 "const uch ZLIB_INTERNAL _length_code[MAX_MATCH-MIN_MATCH+1]= {\n");
365 for (i = 0; i < MAX_MATCH-MIN_MATCH+1; i++) {
366 fprintf(header, "%2u%s", _length_code[i],
367 SEPARATOR(i, MAX_MATCH-MIN_MATCH, 20));
368 }
369
370 fprintf(header, "local const int base_length[LENGTH_CODES] = {\n");
371 for (i = 0; i < LENGTH_CODES; i++) {
372 fprintf(header, "%1u%s", base_length[i],
373 SEPARATOR(i, LENGTH_CODES-1, 20));
374 }
375
376 fprintf(header, "local const int base_dist[D_CODES] = {\n");
377 for (i = 0; i < D_CODES; i++) {
378 fprintf(header, "%5u%s", base_dist[i],
379 SEPARATOR(i, D_CODES-1, 10));
380 }
381
382 fclose(header);
383}
384#endif /* GEN_TREES_H */
385
386/* ===========================================================================
387 * Initialize the tree data structures for a new zlib stream.
388 */
389void ZLIB_INTERNAL _tr_init(s)
390 deflate_state *s;
391{
392 tr_static_init();
393
394 s->l_desc.dyn_tree = s->dyn_ltree;
395 s->l_desc.stat_desc = &static_l_desc;
396
397 s->d_desc.dyn_tree = s->dyn_dtree;
398 s->d_desc.stat_desc = &static_d_desc;
399
400 s->bl_desc.dyn_tree = s->bl_tree;
401 s->bl_desc.stat_desc = &static_bl_desc;
402
403 s->bi_buf = 0;
404 s->bi_valid = 0;
405#ifdef DEBUG
406 s->compressed_len = 0L;
407 s->bits_sent = 0L;
408#endif
409
410 /* Initialize the first block of the first file: */
411 init_block(s);
412}
413
414/* ===========================================================================
415 * Initialize a new block.
416 */
417local void init_block(s)
418 deflate_state *s;
419{
420 int n; /* iterates over tree elements */
421
422 /* Initialize the trees. */
423 for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0;
424 for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0;
425 for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0;
426
427 s->dyn_ltree[END_BLOCK].Freq = 1;
428 s->opt_len = s->static_len = 0L;
429 s->last_lit = s->matches = 0;
430}
431
432#define SMALLEST 1
433/* Index within the heap array of least frequent node in the Huffman tree */
434
435
436/* ===========================================================================
437 * Remove the smallest element from the heap and recreate the heap with
438 * one less element. Updates heap and heap_len.
439 */
440#define pqremove(s, tree, top) \
441{\
442 top = s->heap[SMALLEST]; \
443 s->heap[SMALLEST] = s->heap[s->heap_len--]; \
444 pqdownheap(s, tree, SMALLEST); \
445}
446
447/* ===========================================================================
448 * Compares to subtrees, using the tree depth as tie breaker when
449 * the subtrees have equal frequency. This minimizes the worst case length.
450 */
451#define smaller(tree, n, m, depth) \
452 (tree[n].Freq < tree[m].Freq || \
453 (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m]))
454
455/* ===========================================================================
456 * Restore the heap property by moving down the tree starting at node k,
457 * exchanging a node with the smallest of its two sons if necessary, stopping
458 * when the heap property is re-established (each father smaller than its
459 * two sons).
460 */
461local void pqdownheap(s, tree, k)
462 deflate_state *s;
463 ct_data *tree; /* the tree to restore */
464 int k; /* node to move down */
465{
466 int v = s->heap[k];
467 int j = k << 1; /* left son of k */
468 while (j <= s->heap_len) {
469 /* Set j to the smallest of the two sons: */
470 if (j < s->heap_len &&
471 smaller(tree, s->heap[j+1], s->heap[j], s->depth)) {
472 j++;
473 }
474 /* Exit if v is smaller than both sons */
475 if (smaller(tree, v, s->heap[j], s->depth)) break;
476
477 /* Exchange v with the smallest son */
478 s->heap[k] = s->heap[j]; k = j;
479
480 /* And continue down the tree, setting j to the left son of k */
481 j <<= 1;
482 }
483 s->heap[k] = v;
484}
485
486/* ===========================================================================
487 * Compute the optimal bit lengths for a tree and update the total bit length
488 * for the current block.
489 * IN assertion: the fields freq and dad are set, heap[heap_max] and
490 * above are the tree nodes sorted by increasing frequency.
491 * OUT assertions: the field len is set to the optimal bit length, the
492 * array bl_count contains the frequencies for each bit length.
493 * The length opt_len is updated; static_len is also updated if stree is
494 * not null.
495 */
496local void gen_bitlen(s, desc)
497 deflate_state *s;
498 tree_desc *desc; /* the tree descriptor */
499{
500 ct_data *tree = desc->dyn_tree;
501 int max_code = desc->max_code;
502 const ct_data *stree = desc->stat_desc->static_tree;
503 const intf *extra = desc->stat_desc->extra_bits;
504 int base = desc->stat_desc->extra_base;
505 int max_length = desc->stat_desc->max_length;
506 int h; /* heap index */
507 int n, m; /* iterate over the tree elements */
508 int bits; /* bit length */
509 int xbits; /* extra bits */
510 ush f; /* frequency */
511 int overflow = 0; /* number of elements with bit length too large */
512
513 for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0;
514
515 /* In a first pass, compute the optimal bit lengths (which may
516 * overflow in the case of the bit length tree).
517 */
518 tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */
519
520 for (h = s->heap_max+1; h < HEAP_SIZE; h++) {
521 n = s->heap[h];
522 bits = tree[tree[n].Dad].Len + 1;
523 if (bits > max_length) bits = max_length, overflow++;
524 tree[n].Len = (ush)bits;
525 /* We overwrite tree[n].Dad which is no longer needed */
526
527 if (n > max_code) continue; /* not a leaf node */
528
529 s->bl_count[bits]++;
530 xbits = 0;
531 if (n >= base) xbits = extra[n-base];
532 f = tree[n].Freq;
533 s->opt_len += (ulg)f * (bits + xbits);
534 if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits);
535 }
536 if (overflow == 0) return;
537
538 Trace((stderr,"\nbit length overflow\n"));
539 /* This happens for example on obj2 and pic of the Calgary corpus */
540
541 /* Find the first bit length which could increase: */
542 do {
543 bits = max_length-1;
544 while (s->bl_count[bits] == 0) bits--;
545 s->bl_count[bits]--; /* move one leaf down the tree */
546 s->bl_count[bits+1] += 2; /* move one overflow item as its brother */
547 s->bl_count[max_length]--;
548 /* The brother of the overflow item also moves one step up,
549 * but this does not affect bl_count[max_length]
550 */
551 overflow -= 2;
552 } while (overflow > 0);
553
554 /* Now recompute all bit lengths, scanning in increasing frequency.
555 * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all
556 * lengths instead of fixing only the wrong ones. This idea is taken
557 * from 'ar' written by Haruhiko Okumura.)
558 */
559 for (bits = max_length; bits != 0; bits--) {
560 n = s->bl_count[bits];
561 while (n != 0) {
562 m = s->heap[--h];
563 if (m > max_code) continue;
564 if ((unsigned) tree[m].Len != (unsigned) bits) {
565 Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits));
566 s->opt_len += ((long)bits - (long)tree[m].Len)
567 *(long)tree[m].Freq;
568 tree[m].Len = (ush)bits;
569 }
570 n--;
571 }
572 }
573}
574
575/* ===========================================================================
576 * Generate the codes for a given tree and bit counts (which need not be
577 * optimal).
578 * IN assertion: the array bl_count contains the bit length statistics for
579 * the given tree and the field len is set for all tree elements.
580 * OUT assertion: the field code is set for all tree elements of non
581 * zero code length.
582 */
583local void gen_codes (tree, max_code, bl_count)
584 ct_data *tree; /* the tree to decorate */
585 int max_code; /* largest code with non zero frequency */
586 ushf *bl_count; /* number of codes at each bit length */
587{
588 ush next_code[MAX_BITS+1]; /* next code value for each bit length */
589 ush code = 0; /* running code value */
590 int bits; /* bit index */
591 int n; /* code index */
592
593 /* The distribution counts are first used to generate the code values
594 * without bit reversal.
595 */
596 for (bits = 1; bits <= MAX_BITS; bits++) {
597 next_code[bits] = code = (code + bl_count[bits-1]) << 1;
598 }
599 /* Check that the bit counts in bl_count are consistent. The last code
600 * must be all ones.
601 */
602 Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1,
603 "inconsistent bit counts");
604 Tracev((stderr,"\ngen_codes: max_code %d ", max_code));
605
606 for (n = 0; n <= max_code; n++) {
607 int len = tree[n].Len;
608 if (len == 0) continue;
609 /* Now reverse the bits */
610 tree[n].Code = bi_reverse(next_code[len]++, len);
611
612 Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ",
613 n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1));
614 }
615}
616
617/* ===========================================================================
618 * Construct one Huffman tree and assigns the code bit strings and lengths.
619 * Update the total bit length for the current block.
620 * IN assertion: the field freq is set for all tree elements.
621 * OUT assertions: the fields len and code are set to the optimal bit length
622 * and corresponding code. The length opt_len is updated; static_len is
623 * also updated if stree is not null. The field max_code is set.
624 */
625local void build_tree(s, desc)
626 deflate_state *s;
627 tree_desc *desc; /* the tree descriptor */
628{
629 ct_data *tree = desc->dyn_tree;
630 const ct_data *stree = desc->stat_desc->static_tree;
631 int elems = desc->stat_desc->elems;
632 int n, m; /* iterate over heap elements */
633 int max_code = -1; /* largest code with non zero frequency */
634 int node; /* new node being created */
635
636 /* Construct the initial heap, with least frequent element in
637 * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1].
638 * heap[0] is not used.
639 */
640 s->heap_len = 0, s->heap_max = HEAP_SIZE;
641
642 for (n = 0; n < elems; n++) {
643 if (tree[n].Freq != 0) {
644 s->heap[++(s->heap_len)] = max_code = n;
645 s->depth[n] = 0;
646 } else {
647 tree[n].Len = 0;
648 }
649 }
650
651 /* The pkzip format requires that at least one distance code exists,
652 * and that at least one bit should be sent even if there is only one
653 * possible code. So to avoid special checks later on we force at least
654 * two codes of non zero frequency.
655 */
656 while (s->heap_len < 2) {
657 node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0);
658 tree[node].Freq = 1;
659 s->depth[node] = 0;
660 s->opt_len--; if (stree) s->static_len -= stree[node].Len;
661 /* node is 0 or 1 so it does not have extra bits */
662 }
663 desc->max_code = max_code;
664
665 /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree,
666 * establish sub-heaps of increasing lengths:
667 */
668 for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, n);
669
670 /* Construct the Huffman tree by repeatedly combining the least two
671 * frequent nodes.
672 */
673 node = elems; /* next internal node of the tree */
674 do {
675 pqremove(s, tree, n); /* n = node of least frequency */
676 m = s->heap[SMALLEST]; /* m = node of next least frequency */
677
678 s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */
679 s->heap[--(s->heap_max)] = m;
680
681 /* Create a new node father of n and m */
682 tree[node].Freq = tree[n].Freq + tree[m].Freq;
683 s->depth[node] = (uch)((s->depth[n] >= s->depth[m] ?
684 s->depth[n] : s->depth[m]) + 1);
685 tree[n].Dad = tree[m].Dad = (ush)node;
686#ifdef DUMP_BL_TREE
687 if (tree == s->bl_tree) {
688 fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)",
689 node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq);
690 }
691#endif
692 /* and insert the new node in the heap */
693 s->heap[SMALLEST] = node++;
694 pqdownheap(s, tree, SMALLEST);
695
696 } while (s->heap_len >= 2);
697
698 s->heap[--(s->heap_max)] = s->heap[SMALLEST];
699
700 /* At this point, the fields freq and dad are set. We can now
701 * generate the bit lengths.
702 */
703 gen_bitlen(s, (tree_desc *)desc);
704
705 /* The field len is now set, we can generate the bit codes */
706 gen_codes ((ct_data *)tree, max_code, s->bl_count);
707}
708
709/* ===========================================================================
710 * Scan a literal or distance tree to determine the frequencies of the codes
711 * in the bit length tree.
712 */
713local void scan_tree (s, tree, max_code)
714 deflate_state *s;
715 ct_data *tree; /* the tree to be scanned */
716 int max_code; /* and its largest code of non zero frequency */
717{
718 int n; /* iterates over all tree elements */
719 int prevlen = -1; /* last emitted length */
720 int curlen; /* length of current code */
721 int nextlen = tree[0].Len; /* length of next code */
722 int count = 0; /* repeat count of the current code */
723 int max_count = 7; /* max repeat count */
724 int min_count = 4; /* min repeat count */
725
726 if (nextlen == 0) max_count = 138, min_count = 3;
727 tree[max_code+1].Len = (ush)0xffff; /* guard */
728
729 for (n = 0; n <= max_code; n++) {
730 curlen = nextlen; nextlen = tree[n+1].Len;
731 if (++count < max_count && curlen == nextlen) {
732 continue;
733 } else if (count < min_count) {
734 s->bl_tree[curlen].Freq += count;
735 } else if (curlen != 0) {
736 if (curlen != prevlen) s->bl_tree[curlen].Freq++;
737 s->bl_tree[REP_3_6].Freq++;
738 } else if (count <= 10) {
739 s->bl_tree[REPZ_3_10].Freq++;
740 } else {
741 s->bl_tree[REPZ_11_138].Freq++;
742 }
743 count = 0; prevlen = curlen;
744 if (nextlen == 0) {
745 max_count = 138, min_count = 3;
746 } else if (curlen == nextlen) {
747 max_count = 6, min_count = 3;
748 } else {
749 max_count = 7, min_count = 4;
750 }
751 }
752}
753
754/* ===========================================================================
755 * Send a literal or distance tree in compressed form, using the codes in
756 * bl_tree.
757 */
758local void send_tree (s, tree, max_code)
759 deflate_state *s;
760 ct_data *tree; /* the tree to be scanned */
761 int max_code; /* and its largest code of non zero frequency */
762{
763 int n; /* iterates over all tree elements */
764 int prevlen = -1; /* last emitted length */
765 int curlen; /* length of current code */
766 int nextlen = tree[0].Len; /* length of next code */
767 int count = 0; /* repeat count of the current code */
768 int max_count = 7; /* max repeat count */
769 int min_count = 4; /* min repeat count */
770
771 /* tree[max_code+1].Len = -1; */ /* guard already set */
772 if (nextlen == 0) max_count = 138, min_count = 3;
773
774 for (n = 0; n <= max_code; n++) {
775 curlen = nextlen; nextlen = tree[n+1].Len;
776 if (++count < max_count && curlen == nextlen) {
777 continue;
778 } else if (count < min_count) {
779 do { send_code(s, curlen, s->bl_tree); } while (--count != 0);
780
781 } else if (curlen != 0) {
782 if (curlen != prevlen) {
783 send_code(s, curlen, s->bl_tree); count--;
784 }
785 Assert(count >= 3 && count <= 6, " 3_6?");
786 send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2);
787
788 } else if (count <= 10) {
789 send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3);
790
791 } else {
792 send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7);
793 }
794 count = 0; prevlen = curlen;
795 if (nextlen == 0) {
796 max_count = 138, min_count = 3;
797 } else if (curlen == nextlen) {
798 max_count = 6, min_count = 3;
799 } else {
800 max_count = 7, min_count = 4;
801 }
802 }
803}
804
805/* ===========================================================================
806 * Construct the Huffman tree for the bit lengths and return the index in
807 * bl_order of the last bit length code to send.
808 */
809local int build_bl_tree(s)
810 deflate_state *s;
811{
812 int max_blindex; /* index of last bit length code of non zero freq */
813
814 /* Determine the bit length frequencies for literal and distance trees */
815 scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code);
816 scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code);
817
818 /* Build the bit length tree: */
819 build_tree(s, (tree_desc *)(&(s->bl_desc)));
820 /* opt_len now includes the length of the tree representations, except
821 * the lengths of the bit lengths codes and the 5+5+4 bits for the counts.
822 */
823
824 /* Determine the number of bit length codes to send. The pkzip format
825 * requires that at least 4 bit length codes be sent. (appnote.txt says
826 * 3 but the actual value used is 4.)
827 */
828 for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) {
829 if (s->bl_tree[bl_order[max_blindex]].Len != 0) break;
830 }
831 /* Update opt_len to include the bit length tree and counts */
832 s->opt_len += 3*(max_blindex+1) + 5+5+4;
833 Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld",
834 s->opt_len, s->static_len));
835
836 return max_blindex;
837}
838
839/* ===========================================================================
840 * Send the header for a block using dynamic Huffman trees: the counts, the
841 * lengths of the bit length codes, the literal tree and the distance tree.
842 * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.
843 */
844local void send_all_trees(s, lcodes, dcodes, blcodes)
845 deflate_state *s;
846 int lcodes, dcodes, blcodes; /* number of codes for each tree */
847{
848 int rank; /* index in bl_order */
849
850 Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes");
851 Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES,
852 "too many codes");
853 Tracev((stderr, "\nbl counts: "));
854 send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */
855 send_bits(s, dcodes-1, 5);
856 send_bits(s, blcodes-4, 4); /* not -3 as stated in appnote.txt */
857 for (rank = 0; rank < blcodes; rank++) {
858 Tracev((stderr, "\nbl code %2d ", bl_order[rank]));
859 send_bits(s, s->bl_tree[bl_order[rank]].Len, 3);
860 }
861 Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent));
862
863 send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */
864 Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent));
865
866 send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */
867 Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent));
868}
869
870/* ===========================================================================
871 * Send a stored block
872 */
873void ZLIB_INTERNAL _tr_stored_block(s, buf, stored_len, last)
874 deflate_state *s;
875 charf *buf; /* input block */
876 ulg stored_len; /* length of input block */
877 int last; /* one if this is the last block for a file */
878{
879 send_bits(s, (STORED_BLOCK<<1)+last, 3); /* send block type */
880#ifdef DEBUG
881 s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L;
882 s->compressed_len += (stored_len + 4) << 3;
883#endif
884 copy_block(s, buf, (unsigned)stored_len, 1); /* with header */
885}
886
887/* ===========================================================================
888 * Flush the bits in the bit buffer to pending output (leaves at most 7 bits)
889 */
890void ZLIB_INTERNAL _tr_flush_bits(s)
891 deflate_state *s;
892{
893 bi_flush(s);
894}
895
896/* ===========================================================================
897 * Send one empty static block to give enough lookahead for inflate.
898 * This takes 10 bits, of which 7 may remain in the bit buffer.
899 */
900void ZLIB_INTERNAL _tr_align(s)
901 deflate_state *s;
902{
903 send_bits(s, STATIC_TREES<<1, 3);
904 send_code(s, END_BLOCK, static_ltree);
905#ifdef DEBUG
906 s->compressed_len += 10L; /* 3 for block type, 7 for EOB */
907#endif
908 bi_flush(s);
909}
910
911/* ===========================================================================
912 * Determine the best encoding for the current block: dynamic trees, static
913 * trees or store, and output the encoded block to the zip file.
914 */
915void ZLIB_INTERNAL _tr_flush_block(s, buf, stored_len, last)
916 deflate_state *s;
917 charf *buf; /* input block, or NULL if too old */
918 ulg stored_len; /* length of input block */
919 int last; /* one if this is the last block for a file */
920{
f3919878 921 int max_blindex = 0; /* index of last bit length code of non zero freq */
0fa01ec7 922#ifndef ZLIB_PM3_TUNED
8e074056 923 ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */
924
f3919878 925 /* Build the Huffman trees unless a stored block is forced */
926 if (s->level > 0) {
0fa01ec7 927#endif
f3919878 928 /* Check if the file is binary or text */
929 if (s->strm->data_type == Z_UNKNOWN)
930 s->strm->data_type = detect_data_type(s);
931
932 /* Construct the literal and distance trees */
933 build_tree(s, (tree_desc *)(&(s->l_desc)));
934 Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len,
935 s->static_len));
936
937 build_tree(s, (tree_desc *)(&(s->d_desc)));
938 Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len,
939 s->static_len));
940 /* At this point, opt_len and static_len are the total bit lengths of
941 * the compressed block data, excluding the tree representations.
942 */
943
944 /* Build the bit length tree for the above two trees, and get the index
945 * in bl_order of the last bit length code to send.
946 */
947 max_blindex = build_bl_tree(s);
948
8e074056 949#ifndef ZLIB_PM3_TUNED
f3919878 950 /* Determine the best encoding. Compute the block lengths in bytes. */
951 opt_lenb = (s->opt_len+3+7)>>3;
952 static_lenb = (s->static_len+3+7)>>3;
953
954 Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ",
955 opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len,
956 s->last_lit));
957
958 if (static_lenb <= opt_lenb) opt_lenb = static_lenb;
959
960 } else {
961 Assert(buf != (char*)0, "lost buf");
962 opt_lenb = static_lenb = stored_len + 5; /* force a stored block */
963 }
964
965#ifdef FORCE_STORED
966 if (buf != (char*)0) { /* force stored block */
967#else
968 if (stored_len+4 <= opt_lenb && buf != (char*)0) {
969 /* 4: two words for the lengths */
970#endif
971 /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.
972 * Otherwise we can't have processed more than WSIZE input bytes since
973 * the last block flush, because compression would have been
974 * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to
975 * transform a block into a stored block.
976 */
977 _tr_stored_block(s, buf, stored_len, last);
978
979#ifdef FORCE_STATIC
980 } else if (static_lenb >= 0) { /* force static trees */
981#else
982 } else if (s->strategy == Z_FIXED || static_lenb == opt_lenb) {
983#endif
984 send_bits(s, (STATIC_TREES<<1)+last, 3);
985 compress_block(s, (const ct_data *)static_ltree,
986 (const ct_data *)static_dtree);
987#ifdef DEBUG
988 s->compressed_len += 3 + s->static_len;
989#endif
990 } else {
8e074056 991#endif /* !ZLIB_PM3_TUNED */
0fa01ec7 992 send_bits(s, (DYN_TREES<<1)+last, 3);
f3919878 993 send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1,
994 max_blindex+1);
995 compress_block(s, (const ct_data *)s->dyn_ltree,
996 (const ct_data *)s->dyn_dtree);
997#ifdef DEBUG
998 s->compressed_len += 3 + s->opt_len;
999#endif
4b3f6d79 1000#ifndef ZLIB_PM3_TUNED
f3919878 1001 }
4b3f6d79 1002#endif
f3919878 1003 Assert (s->compressed_len == s->bits_sent, "bad compressed size");
1004 /* The above check is made mod 2^32, for files larger than 512 MB
1005 * and uLong implemented on 32 bits.
1006 */
1007 init_block(s);
1008
1009 if (last) {
1010 bi_windup(s);
1011#ifdef DEBUG
1012 s->compressed_len += 7; /* align on byte boundary */
1013#endif
1014 }
1015 Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3,
1016 s->compressed_len-7*last));
1017}
1018
1019/* ===========================================================================
1020 * Save the match info and tally the frequency counts. Return true if
1021 * the current block must be flushed.
1022 */
1023int ZLIB_INTERNAL _tr_tally (s, dist, lc)
1024 deflate_state *s;
1025 unsigned dist; /* distance of matched string */
1026 unsigned lc; /* match length-MIN_MATCH or unmatched char (if dist==0) */
1027{
1028 s->d_buf[s->last_lit] = (ush)dist;
1029 s->l_buf[s->last_lit++] = (uch)lc;
1030 if (dist == 0) {
1031 /* lc is the unmatched char */
1032 s->dyn_ltree[lc].Freq++;
1033 } else {
1034 s->matches++;
1035 /* Here, lc is the match length - MIN_MATCH */
1036 dist--; /* dist = match distance - 1 */
1037 Assert((ush)dist < (ush)MAX_DIST(s) &&
1038 (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) &&
1039 (ush)d_code(dist) < (ush)D_CODES, "_tr_tally: bad match");
1040
1041 s->dyn_ltree[_length_code[lc]+LITERALS+1].Freq++;
1042 s->dyn_dtree[d_code(dist)].Freq++;
1043 }
1044
1045#ifdef TRUNCATE_BLOCK
1046 /* Try to guess if it is profitable to stop the current block here */
1047 if ((s->last_lit & 0x1fff) == 0 && s->level > 2) {
1048 /* Compute an upper bound for the compressed length */
1049 ulg out_length = (ulg)s->last_lit*8L;
1050 ulg in_length = (ulg)((long)s->strstart - s->block_start);
1051 int dcode;
1052 for (dcode = 0; dcode < D_CODES; dcode++) {
1053 out_length += (ulg)s->dyn_dtree[dcode].Freq *
1054 (5L+extra_dbits[dcode]);
1055 }
1056 out_length >>= 3;
1057 Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ",
1058 s->last_lit, in_length, out_length,
1059 100L - out_length*100L/in_length));
1060 if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1;
1061 }
1062#endif
1063 return (s->last_lit == s->lit_bufsize-1);
1064 /* We avoid equality with lit_bufsize because of wraparound at 64K
1065 * on 16 bit machines and because stored blocks are restricted to
1066 * 64K-1 bytes.
1067 */
1068}
1069
1070/* ===========================================================================
1071 * Send the block data compressed using the given Huffman trees
1072 */
1073local void compress_block(s, ltree, dtree)
1074 deflate_state *s;
1075 const ct_data *ltree; /* literal tree */
1076 const ct_data *dtree; /* distance tree */
1077{
1078 unsigned dist; /* distance of matched string */
1079 int lc; /* match length or unmatched char (if dist == 0) */
1080 unsigned lx = 0; /* running index in l_buf */
1081 unsigned code; /* the code to send */
1082 int extra; /* number of extra bits to send */
1083
1084 if (s->last_lit != 0) do {
1085 dist = s->d_buf[lx];
1086 lc = s->l_buf[lx++];
1087 if (dist == 0) {
1088 send_code(s, lc, ltree); /* send a literal byte */
1089 Tracecv(isgraph(lc), (stderr," '%c' ", lc));
1090 } else {
1091 /* Here, lc is the match length - MIN_MATCH */
1092 code = _length_code[lc];
1093 send_code(s, code+LITERALS+1, ltree); /* send the length code */
1094 extra = extra_lbits[code];
1095 if (extra != 0) {
1096 lc -= base_length[code];
1097 send_bits(s, lc, extra); /* send the extra length bits */
1098 }
1099 dist--; /* dist is now the match distance - 1 */
1100 code = d_code(dist);
1101 Assert (code < D_CODES, "bad d_code");
1102
1103 send_code(s, code, dtree); /* send the distance code */
1104 extra = extra_dbits[code];
1105 if (extra != 0) {
1106 dist -= base_dist[code];
1107 send_bits(s, dist, extra); /* send the extra distance bits */
1108 }
1109 } /* literal or match pair ? */
1110
1111 /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */
1112 Assert((uInt)(s->pending) < s->lit_bufsize + 2*lx,
1113 "pendingBuf overflow");
1114
1115 } while (lx < s->last_lit);
1116
1117 send_code(s, END_BLOCK, ltree);
1118}
1119
1120/* ===========================================================================
1121 * Check if the data type is TEXT or BINARY, using the following algorithm:
1122 * - TEXT if the two conditions below are satisfied:
1123 * a) There are no non-portable control characters belonging to the
1124 * "black list" (0..6, 14..25, 28..31).
1125 * b) There is at least one printable character belonging to the
1126 * "white list" (9 {TAB}, 10 {LF}, 13 {CR}, 32..255).
1127 * - BINARY otherwise.
1128 * - The following partially-portable control characters form a
1129 * "gray list" that is ignored in this detection algorithm:
1130 * (7 {BEL}, 8 {BS}, 11 {VT}, 12 {FF}, 26 {SUB}, 27 {ESC}).
1131 * IN assertion: the fields Freq of dyn_ltree are set.
1132 */
1133local int detect_data_type(s)
1134 deflate_state *s;
1135{
1136 /* black_mask is the bit mask of black-listed bytes
1137 * set bits 0..6, 14..25, and 28..31
1138 * 0xf3ffc07f = binary 11110011111111111100000001111111
1139 */
1140 unsigned long black_mask = 0xf3ffc07fUL;
1141 int n;
1142
1143 /* Check for non-textual ("black-listed") bytes. */
1144 for (n = 0; n <= 31; n++, black_mask >>= 1)
1145 if ((black_mask & 1) && (s->dyn_ltree[n].Freq != 0))
1146 return Z_BINARY;
1147
1148 /* Check for textual ("white-listed") bytes. */
1149 if (s->dyn_ltree[9].Freq != 0 || s->dyn_ltree[10].Freq != 0
1150 || s->dyn_ltree[13].Freq != 0)
1151 return Z_TEXT;
1152 for (n = 32; n < LITERALS; n++)
1153 if (s->dyn_ltree[n].Freq != 0)
1154 return Z_TEXT;
1155
1156 /* There are no "black-listed" or "white-listed" bytes:
1157 * this stream either is empty or has tolerated ("gray-listed") bytes only.
1158 */
1159 return Z_BINARY;
1160}
1161
1162/* ===========================================================================
1163 * Reverse the first len bits of a code, using straightforward code (a faster
1164 * method would use a table)
1165 * IN assertion: 1 <= len <= 15
1166 */
1167local unsigned bi_reverse(code, len)
1168 unsigned code; /* the value to invert */
1169 int len; /* its bit length */
1170{
1171 register unsigned res = 0;
1172 do {
1173 res |= code & 1;
1174 code >>= 1, res <<= 1;
1175 } while (--len > 0);
1176 return res >> 1;
1177}
1178
1179/* ===========================================================================
1180 * Flush the bit buffer, keeping at most 7 bits in it.
1181 */
1182local void bi_flush(s)
1183 deflate_state *s;
1184{
1185 if (s->bi_valid == 16) {
1186 put_short(s, s->bi_buf);
1187 s->bi_buf = 0;
1188 s->bi_valid = 0;
1189 } else if (s->bi_valid >= 8) {
1190 put_byte(s, (Byte)s->bi_buf);
1191 s->bi_buf >>= 8;
1192 s->bi_valid -= 8;
1193 }
1194}
1195
1196/* ===========================================================================
1197 * Flush the bit buffer and align the output on a byte boundary
1198 */
1199local void bi_windup(s)
1200 deflate_state *s;
1201{
1202 if (s->bi_valid > 8) {
1203 put_short(s, s->bi_buf);
1204 } else if (s->bi_valid > 0) {
1205 put_byte(s, (Byte)s->bi_buf);
1206 }
1207 s->bi_buf = 0;
1208 s->bi_valid = 0;
1209#ifdef DEBUG
1210 s->bits_sent = (s->bits_sent+7) & ~7;
1211#endif
1212}
1213
1214/* ===========================================================================
1215 * Copy a stored block, storing first the length and its
1216 * one's complement if requested.
1217 */
1218local void copy_block(s, buf, len, header)
1219 deflate_state *s;
1220 charf *buf; /* the input data */
1221 unsigned len; /* its length */
1222 int header; /* true if block header must be written */
1223{
1224 bi_windup(s); /* align on byte boundary */
1225
1226 if (header) {
1227 put_short(s, (ush)len);
1228 put_short(s, (ush)~len);
1229#ifdef DEBUG
1230 s->bits_sent += 2*16;
1231#endif
1232 }
1233#ifdef DEBUG
1234 s->bits_sent += (ulg)len<<3;
1235#endif
1236 while (len--) {
1237 put_byte(s, *buf++);
1238 }
1239}
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