1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation. Oracle designates this
7 * particular file as subject to the "Classpath" exception as provided
8 * by Oracle in the LICENSE file that accompanied this code.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 */
24
25 /* pngwutil.c - utilities to write a PNG file
26 *
27 * This file is available under and governed by the GNU General Public
28 * License version 2 only, as published by the Free Software Foundation.
29 * However, the following notice accompanied the original version of this
30 * file and, per its terms, should not be removed:
31 *
32 * Last changed in libpng 1.6.19 [November 12, 2015]
33 * Copyright (c) 1998-2015 Glenn Randers-Pehrson
34 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
35 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
36 *
37 * This code is released under the libpng license.
38 * For conditions of distribution and use, see the disclaimer
39 * and license in png.h
40 */
41
42 #include "pngpriv.h"
43
44 #ifdef PNG_WRITE_SUPPORTED
45
46 #ifdef PNG_WRITE_INT_FUNCTIONS_SUPPORTED
47 /* Place a 32-bit number into a buffer in PNG byte order. We work
48 * with unsigned numbers for convenience, although one supported
49 * ancillary chunk uses signed (two's complement) numbers.
50 */
51 void PNGAPI
52 png_save_uint_32(png_bytep buf, png_uint_32 i)
53 {
54 buf[0] = (png_byte)(i >> 24);
55 buf[1] = (png_byte)(i >> 16);
56 buf[2] = (png_byte)(i >> 8);
57 buf[3] = (png_byte)(i );
58 }
59
60 /* Place a 16-bit number into a buffer in PNG byte order.
61 * The parameter is declared unsigned int, not png_uint_16,
62 * just to avoid potential problems on pre-ANSI C compilers.
63 */
64 void PNGAPI
65 png_save_uint_16(png_bytep buf, unsigned int i)
66 {
67 buf[0] = (png_byte)(i >> 8);
68 buf[1] = (png_byte)(i );
69 }
70 #endif
71
72 /* Simple function to write the signature. If we have already written
73 * the magic bytes of the signature, or more likely, the PNG stream is
74 * being embedded into another stream and doesn't need its own signature,
75 * we should call png_set_sig_bytes() to tell libpng how many of the
76 * bytes have already been written.
77 */
78 void PNGAPI
79 png_write_sig(png_structrp png_ptr)
80 {
81 png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
82
83 #ifdef PNG_IO_STATE_SUPPORTED
84 /* Inform the I/O callback that the signature is being written */
85 png_ptr->io_state = PNG_IO_WRITING | PNG_IO_SIGNATURE;
86 #endif
87
88 /* Write the rest of the 8 byte signature */
89 png_write_data(png_ptr, &png_signature[png_ptr->sig_bytes],
90 (png_size_t)(8 - png_ptr->sig_bytes));
91
92 if (png_ptr->sig_bytes < 3)
93 png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
94 }
95
96 /* Write the start of a PNG chunk. The type is the chunk type.
97 * The total_length is the sum of the lengths of all the data you will be
98 * passing in png_write_chunk_data().
99 */
100 static void
101 png_write_chunk_header(png_structrp png_ptr, png_uint_32 chunk_name,
102 png_uint_32 length)
103 {
104 png_byte buf[8];
105
106 #if defined(PNG_DEBUG) && (PNG_DEBUG > 0)
107 PNG_CSTRING_FROM_CHUNK(buf, chunk_name);
108 png_debug2(0, "Writing %s chunk, length = %lu", buf, (unsigned long)length);
109 #endif
110
111 if (png_ptr == NULL)
112 return;
113
114 #ifdef PNG_IO_STATE_SUPPORTED
115 /* Inform the I/O callback that the chunk header is being written.
116 * PNG_IO_CHUNK_HDR requires a single I/O call.
117 */
118 png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_HDR;
119 #endif
120
121 /* Write the length and the chunk name */
122 png_save_uint_32(buf, length);
123 png_save_uint_32(buf + 4, chunk_name);
124 png_write_data(png_ptr, buf, 8);
125
126 /* Put the chunk name into png_ptr->chunk_name */
127 png_ptr->chunk_name = chunk_name;
128
129 /* Reset the crc and run it over the chunk name */
130 png_reset_crc(png_ptr);
131
132 png_calculate_crc(png_ptr, buf + 4, 4);
133
134 #ifdef PNG_IO_STATE_SUPPORTED
135 /* Inform the I/O callback that chunk data will (possibly) be written.
136 * PNG_IO_CHUNK_DATA does NOT require a specific number of I/O calls.
137 */
138 png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_DATA;
139 #endif
140 }
141
142 void PNGAPI
143 png_write_chunk_start(png_structrp png_ptr, png_const_bytep chunk_string,
144 png_uint_32 length)
145 {
146 png_write_chunk_header(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), length);
147 }
148
149 /* Write the data of a PNG chunk started with png_write_chunk_header().
150 * Note that multiple calls to this function are allowed, and that the
151 * sum of the lengths from these calls *must* add up to the total_length
152 * given to png_write_chunk_header().
153 */
154 void PNGAPI
155 png_write_chunk_data(png_structrp png_ptr, png_const_bytep data,
156 png_size_t length)
157 {
158 /* Write the data, and run the CRC over it */
159 if (png_ptr == NULL)
160 return;
161
162 if (data != NULL && length > 0)
163 {
164 png_write_data(png_ptr, data, length);
165
166 /* Update the CRC after writing the data,
167 * in case the user I/O routine alters it.
168 */
169 png_calculate_crc(png_ptr, data, length);
170 }
171 }
172
173 /* Finish a chunk started with png_write_chunk_header(). */
174 void PNGAPI
175 png_write_chunk_end(png_structrp png_ptr)
176 {
177 png_byte buf[4];
178
179 if (png_ptr == NULL) return;
180
181 #ifdef PNG_IO_STATE_SUPPORTED
182 /* Inform the I/O callback that the chunk CRC is being written.
183 * PNG_IO_CHUNK_CRC requires a single I/O function call.
184 */
185 png_ptr->io_state = PNG_IO_WRITING | PNG_IO_CHUNK_CRC;
186 #endif
187
188 /* Write the crc in a single operation */
189 png_save_uint_32(buf, png_ptr->crc);
190
191 png_write_data(png_ptr, buf, (png_size_t)4);
192 }
193
194 /* Write a PNG chunk all at once. The type is an array of ASCII characters
195 * representing the chunk name. The array must be at least 4 bytes in
196 * length, and does not need to be null terminated. To be safe, pass the
197 * pre-defined chunk names here, and if you need a new one, define it
198 * where the others are defined. The length is the length of the data.
199 * All the data must be present. If that is not possible, use the
200 * png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end()
201 * functions instead.
202 */
203 static void
204 png_write_complete_chunk(png_structrp png_ptr, png_uint_32 chunk_name,
205 png_const_bytep data, png_size_t length)
206 {
207 if (png_ptr == NULL)
208 return;
209
210 /* On 64-bit architectures 'length' may not fit in a png_uint_32. */
211 if (length > PNG_UINT_31_MAX)
212 png_error(png_ptr, "length exceeds PNG maximum");
213
214 png_write_chunk_header(png_ptr, chunk_name, (png_uint_32)length);
215 png_write_chunk_data(png_ptr, data, length);
216 png_write_chunk_end(png_ptr);
217 }
218
219 /* This is the API that calls the internal function above. */
220 void PNGAPI
221 png_write_chunk(png_structrp png_ptr, png_const_bytep chunk_string,
222 png_const_bytep data, png_size_t length)
223 {
224 png_write_complete_chunk(png_ptr, PNG_CHUNK_FROM_STRING(chunk_string), data,
225 length);
226 }
227
228 /* This is used below to find the size of an image to pass to png_deflate_claim,
229 * so it only needs to be accurate if the size is less than 16384 bytes (the
230 * point at which a lower LZ window size can be used.)
231 */
232 static png_alloc_size_t
233 png_image_size(png_structrp png_ptr)
234 {
235 /* Only return sizes up to the maximum of a png_uint_32; do this by limiting
236 * the width and height used to 15 bits.
237 */
238 png_uint_32 h = png_ptr->height;
239
240 if (png_ptr->rowbytes < 32768 && h < 32768)
241 {
242 if (png_ptr->interlaced != 0)
243 {
244 /* Interlacing makes the image larger because of the replication of
245 * both the filter byte and the padding to a byte boundary.
246 */
247 png_uint_32 w = png_ptr->width;
248 unsigned int pd = png_ptr->pixel_depth;
249 png_alloc_size_t cb_base;
250 int pass;
251
252 for (cb_base=0, pass=0; pass<=6; ++pass)
253 {
254 png_uint_32 pw = PNG_PASS_COLS(w, pass);
255
256 if (pw > 0)
257 cb_base += (PNG_ROWBYTES(pd, pw)+1) * PNG_PASS_ROWS(h, pass);
258 }
259
260 return cb_base;
261 }
262
263 else
264 return (png_ptr->rowbytes+1) * h;
265 }
266
267 else
268 return 0xffffffffU;
269 }
270
271 #ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
272 /* This is the code to hack the first two bytes of the deflate stream (the
273 * deflate header) to correct the windowBits value to match the actual data
274 * size. Note that the second argument is the *uncompressed* size but the
275 * first argument is the *compressed* data (and it must be deflate
276 * compressed.)
277 */
278 static void
279 optimize_cmf(png_bytep data, png_alloc_size_t data_size)
280 {
281 /* Optimize the CMF field in the zlib stream. The resultant zlib stream is
282 * still compliant to the stream specification.
283 */
284 if (data_size <= 16384) /* else windowBits must be 15 */
285 {
286 unsigned int z_cmf = data[0]; /* zlib compression method and flags */
287
288 if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70)
289 {
290 unsigned int z_cinfo;
291 unsigned int half_z_window_size;
292
293 z_cinfo = z_cmf >> 4;
294 half_z_window_size = 1U << (z_cinfo + 7);
295
296 if (data_size <= half_z_window_size) /* else no change */
297 {
298 unsigned int tmp;
299
300 do
301 {
302 half_z_window_size >>= 1;
303 --z_cinfo;
304 }
305 while (z_cinfo > 0 && data_size <= half_z_window_size);
306
307 z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4);
308
309 data[0] = (png_byte)z_cmf;
310 tmp = data[1] & 0xe0;
311 tmp += 0x1f - ((z_cmf << 8) + tmp) % 0x1f;
312 data[1] = (png_byte)tmp;
313 }
314 }
315 }
316 }
317 #endif /* WRITE_OPTIMIZE_CMF */
318
319 /* Initialize the compressor for the appropriate type of compression. */
320 static int
321 png_deflate_claim(png_structrp png_ptr, png_uint_32 owner,
322 png_alloc_size_t data_size)
323 {
324 if (png_ptr->zowner != 0)
325 {
326 #if defined(PNG_WARNINGS_SUPPORTED) || defined(PNG_ERROR_TEXT_SUPPORTED)
327 char msg[64];
328
329 PNG_STRING_FROM_CHUNK(msg, owner);
330 msg[4] = ':';
331 msg[5] = ' ';
332 PNG_STRING_FROM_CHUNK(msg+6, png_ptr->zowner);
333 /* So the message that results is "<chunk> using zstream"; this is an
334 * internal error, but is very useful for debugging. i18n requirements
335 * are minimal.
336 */
337 (void)png_safecat(msg, (sizeof msg), 10, " using zstream");
338 #endif
339 #if PNG_RELEASE_BUILD
340 png_warning(png_ptr, msg);
341
342 /* Attempt sane error recovery */
343 if (png_ptr->zowner == png_IDAT) /* don't steal from IDAT */
344 {
345 png_ptr->zstream.msg = PNGZ_MSG_CAST("in use by IDAT");
346 return Z_STREAM_ERROR;
347 }
348
349 png_ptr->zowner = 0;
350 #else
351 png_error(png_ptr, msg);
352 #endif
353 }
354
355 {
356 int level = png_ptr->zlib_level;
357 int method = png_ptr->zlib_method;
358 int windowBits = png_ptr->zlib_window_bits;
359 int memLevel = png_ptr->zlib_mem_level;
360 int strategy; /* set below */
361 int ret; /* zlib return code */
362
363 if (owner == png_IDAT)
364 {
365 if ((png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY) != 0)
366 strategy = png_ptr->zlib_strategy;
367
368 else if (png_ptr->do_filter != PNG_FILTER_NONE)
369 strategy = PNG_Z_DEFAULT_STRATEGY;
370
371 else
372 strategy = PNG_Z_DEFAULT_NOFILTER_STRATEGY;
373 }
374
375 else
376 {
377 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
378 level = png_ptr->zlib_text_level;
379 method = png_ptr->zlib_text_method;
380 windowBits = png_ptr->zlib_text_window_bits;
381 memLevel = png_ptr->zlib_text_mem_level;
382 strategy = png_ptr->zlib_text_strategy;
383 #else
384 /* If customization is not supported the values all come from the
385 * IDAT values except for the strategy, which is fixed to the
386 * default. (This is the pre-1.6.0 behavior too, although it was
387 * implemented in a very different way.)
388 */
389 strategy = Z_DEFAULT_STRATEGY;
390 #endif
391 }
392
393 /* Adjust 'windowBits' down if larger than 'data_size'; to stop this
394 * happening just pass 32768 as the data_size parameter. Notice that zlib
395 * requires an extra 262 bytes in the window in addition to the data to be
396 * able to see the whole of the data, so if data_size+262 takes us to the
397 * next windowBits size we need to fix up the value later. (Because even
398 * though deflate needs the extra window, inflate does not!)
399 */
400 if (data_size <= 16384)
401 {
402 /* IMPLEMENTATION NOTE: this 'half_window_size' stuff is only here to
403 * work round a Microsoft Visual C misbehavior which, contrary to C-90,
404 * widens the result of the following shift to 64-bits if (and,
405 * apparently, only if) it is used in a test.
406 */
407 unsigned int half_window_size = 1U << (windowBits-1);
408
409 while (data_size + 262 <= half_window_size)
410 {
411 half_window_size >>= 1;
412 --windowBits;
413 }
414 }
415
416 /* Check against the previous initialized values, if any. */
417 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0 &&
418 (png_ptr->zlib_set_level != level ||
419 png_ptr->zlib_set_method != method ||
420 png_ptr->zlib_set_window_bits != windowBits ||
421 png_ptr->zlib_set_mem_level != memLevel ||
422 png_ptr->zlib_set_strategy != strategy))
423 {
424 if (deflateEnd(&png_ptr->zstream) != Z_OK)
425 png_warning(png_ptr, "deflateEnd failed (ignored)");
426
427 png_ptr->flags &= ~PNG_FLAG_ZSTREAM_INITIALIZED;
428 }
429
430 /* For safety clear out the input and output pointers (currently zlib
431 * doesn't use them on Init, but it might in the future).
432 */
433 png_ptr->zstream.next_in = NULL;
434 png_ptr->zstream.avail_in = 0;
435 png_ptr->zstream.next_out = NULL;
436 png_ptr->zstream.avail_out = 0;
437
438 /* Now initialize if required, setting the new parameters, otherwise just
439 * to a simple reset to the previous parameters.
440 */
441 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_INITIALIZED) != 0)
442 ret = deflateReset(&png_ptr->zstream);
443
444 else
445 {
446 ret = deflateInit2(&png_ptr->zstream, level, method, windowBits,
447 memLevel, strategy);
448
449 if (ret == Z_OK)
450 png_ptr->flags |= PNG_FLAG_ZSTREAM_INITIALIZED;
451 }
452
453 /* The return code is from either deflateReset or deflateInit2; they have
454 * pretty much the same set of error codes.
455 */
456 if (ret == Z_OK)
457 png_ptr->zowner = owner;
458
459 else
460 png_zstream_error(png_ptr, ret);
461
462 return ret;
463 }
464 }
465
466 /* Clean up (or trim) a linked list of compression buffers. */
467 void /* PRIVATE */
468 png_free_buffer_list(png_structrp png_ptr, png_compression_bufferp *listp)
469 {
470 png_compression_bufferp list = *listp;
471
472 if (list != NULL)
473 {
474 *listp = NULL;
475
476 do
477 {
478 png_compression_bufferp next = list->next;
479
480 png_free(png_ptr, list);
481 list = next;
482 }
483 while (list != NULL);
484 }
485 }
486
487 #ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
488 /* This pair of functions encapsulates the operation of (a) compressing a
489 * text string, and (b) issuing it later as a series of chunk data writes.
490 * The compression_state structure is shared context for these functions
491 * set up by the caller to allow access to the relevant local variables.
492 *
493 * compression_buffer (new in 1.6.0) is just a linked list of zbuffer_size
494 * temporary buffers. From 1.6.0 it is retained in png_struct so that it will
495 * be correctly freed in the event of a write error (previous implementations
496 * just leaked memory.)
497 */
498 typedef struct
499 {
500 png_const_bytep input; /* The uncompressed input data */
501 png_alloc_size_t input_len; /* Its length */
502 png_uint_32 output_len; /* Final compressed length */
503 png_byte output[1024]; /* First block of output */
504 } compression_state;
505
506 static void
507 png_text_compress_init(compression_state *comp, png_const_bytep input,
508 png_alloc_size_t input_len)
509 {
510 comp->input = input;
511 comp->input_len = input_len;
512 comp->output_len = 0;
513 }
514
515 /* Compress the data in the compression state input */
516 static int
517 png_text_compress(png_structrp png_ptr, png_uint_32 chunk_name,
518 compression_state *comp, png_uint_32 prefix_len)
519 {
520 int ret;
521
522 /* To find the length of the output it is necessary to first compress the
523 * input. The result is buffered rather than using the two-pass algorithm
524 * that is used on the inflate side; deflate is assumed to be slower and a
525 * PNG writer is assumed to have more memory available than a PNG reader.
526 *
527 * IMPLEMENTATION NOTE: the zlib API deflateBound() can be used to find an
528 * upper limit on the output size, but it is always bigger than the input
529 * size so it is likely to be more efficient to use this linked-list
530 * approach.
531 */
532 ret = png_deflate_claim(png_ptr, chunk_name, comp->input_len);
533
534 if (ret != Z_OK)
535 return ret;
536
537 /* Set up the compression buffers, we need a loop here to avoid overflowing a
538 * uInt. Use ZLIB_IO_MAX to limit the input. The output is always limited
539 * by the output buffer size, so there is no need to check that. Since this
540 * is ANSI-C we know that an 'int', hence a uInt, is always at least 16 bits
541 * in size.
542 */
543 {
544 png_compression_bufferp *end = &png_ptr->zbuffer_list;
545 png_alloc_size_t input_len = comp->input_len; /* may be zero! */
546 png_uint_32 output_len;
547
548 /* zlib updates these for us: */
549 png_ptr->zstream.next_in = PNGZ_INPUT_CAST(comp->input);
550 png_ptr->zstream.avail_in = 0; /* Set below */
551 png_ptr->zstream.next_out = comp->output;
552 png_ptr->zstream.avail_out = (sizeof comp->output);
553
554 output_len = png_ptr->zstream.avail_out;
555
556 do
557 {
558 uInt avail_in = ZLIB_IO_MAX;
559
560 if (avail_in > input_len)
561 avail_in = (uInt)input_len;
562
563 input_len -= avail_in;
564
565 png_ptr->zstream.avail_in = avail_in;
566
567 if (png_ptr->zstream.avail_out == 0)
568 {
569 png_compression_buffer *next;
570
571 /* Chunk data is limited to 2^31 bytes in length, so the prefix
572 * length must be counted here.
573 */
574 if (output_len + prefix_len > PNG_UINT_31_MAX)
575 {
576 ret = Z_MEM_ERROR;
577 break;
578 }
579
580 /* Need a new (malloc'ed) buffer, but there may be one present
581 * already.
582 */
583 next = *end;
584 if (next == NULL)
585 {
586 next = png_voidcast(png_compression_bufferp, png_malloc_base
587 (png_ptr, PNG_COMPRESSION_BUFFER_SIZE(png_ptr)));
588
589 if (next == NULL)
590 {
591 ret = Z_MEM_ERROR;
592 break;
593 }
594
595 /* Link in this buffer (so that it will be freed later) */
596 next->next = NULL;
597 *end = next;
598 }
599
600 png_ptr->zstream.next_out = next->output;
601 png_ptr->zstream.avail_out = png_ptr->zbuffer_size;
602 output_len += png_ptr->zstream.avail_out;
603
604 /* Move 'end' to the next buffer pointer. */
605 end = &next->next;
606 }
607
608 /* Compress the data */
609 ret = deflate(&png_ptr->zstream,
610 input_len > 0 ? Z_NO_FLUSH : Z_FINISH);
611
612 /* Claw back input data that was not consumed (because avail_in is
613 * reset above every time round the loop).
614 */
615 input_len += png_ptr->zstream.avail_in;
616 png_ptr->zstream.avail_in = 0; /* safety */
617 }
618 while (ret == Z_OK);
619
620 /* There may be some space left in the last output buffer. This needs to
621 * be subtracted from output_len.
622 */
623 output_len -= png_ptr->zstream.avail_out;
624 png_ptr->zstream.avail_out = 0; /* safety */
625 comp->output_len = output_len;
626
627 /* Now double check the output length, put in a custom message if it is
628 * too long. Otherwise ensure the z_stream::msg pointer is set to
629 * something.
630 */
631 if (output_len + prefix_len >= PNG_UINT_31_MAX)
632 {
633 png_ptr->zstream.msg = PNGZ_MSG_CAST("compressed data too long");
634 ret = Z_MEM_ERROR;
635 }
636
637 else
638 png_zstream_error(png_ptr, ret);
639
640 /* Reset zlib for another zTXt/iTXt or image data */
641 png_ptr->zowner = 0;
642
643 /* The only success case is Z_STREAM_END, input_len must be 0; if not this
644 * is an internal error.
645 */
646 if (ret == Z_STREAM_END && input_len == 0)
647 {
648 #ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
649 /* Fix up the deflate header, if required */
650 optimize_cmf(comp->output, comp->input_len);
651 #endif
652 /* But Z_OK is returned, not Z_STREAM_END; this allows the claim
653 * function above to return Z_STREAM_END on an error (though it never
654 * does in the current versions of zlib.)
655 */
656 return Z_OK;
657 }
658
659 else
660 return ret;
661 }
662 }
663
664 /* Ship the compressed text out via chunk writes */
665 static void
666 png_write_compressed_data_out(png_structrp png_ptr, compression_state *comp)
667 {
668 png_uint_32 output_len = comp->output_len;
669 png_const_bytep output = comp->output;
670 png_uint_32 avail = (sizeof comp->output);
671 png_compression_buffer *next = png_ptr->zbuffer_list;
672
673 for (;;)
674 {
675 if (avail > output_len)
676 avail = output_len;
677
678 png_write_chunk_data(png_ptr, output, avail);
679
680 output_len -= avail;
681
682 if (output_len == 0 || next == NULL)
683 break;
684
685 avail = png_ptr->zbuffer_size;
686 output = next->output;
687 next = next->next;
688 }
689
690 /* This is an internal error; 'next' must have been NULL! */
691 if (output_len > 0)
692 png_error(png_ptr, "error writing ancillary chunked compressed data");
693 }
694 #endif /* WRITE_COMPRESSED_TEXT */
695
696 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \
697 defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
698 /* Check that the tEXt or zTXt keyword is valid per PNG 1.0 specification,
699 * and if invalid, correct the keyword rather than discarding the entire
700 * chunk. The PNG 1.0 specification requires keywords 1-79 characters in
701 * length, forbids leading or trailing whitespace, multiple internal spaces,
702 * and the non-break space (0x80) from ISO 8859-1. Returns keyword length.
703 *
704 * The 'new_key' buffer must be 80 characters in size (for the keyword plus a
705 * trailing '\0'). If this routine returns 0 then there was no keyword, or a
706 * valid one could not be generated, and the caller must png_error.
707 */
708 static png_uint_32
709 png_check_keyword(png_structrp png_ptr, png_const_charp key, png_bytep new_key)
710 {
711 png_const_charp orig_key = key;
712 png_uint_32 key_len = 0;
713 int bad_character = 0;
714 int space = 1;
715
716 png_debug(1, "in png_check_keyword");
717
718 if (key == NULL)
719 {
720 *new_key = 0;
721 return 0;
722 }
723
724 while (*key && key_len < 79)
725 {
726 png_byte ch = (png_byte)*key++;
727
728 if ((ch > 32 && ch <= 126) || (ch >= 161 /*&& ch <= 255*/))
729 *new_key++ = ch, ++key_len, space = 0;
730
731 else if (space == 0)
732 {
733 /* A space or an invalid character when one wasn't seen immediately
734 * before; output just a space.
735 */
736 *new_key++ = 32, ++key_len, space = 1;
737
738 /* If the character was not a space then it is invalid. */
739 if (ch != 32)
740 bad_character = ch;
741 }
742
743 else if (bad_character == 0)
744 bad_character = ch; /* just skip it, record the first error */
745 }
746
747 if (key_len > 0 && space != 0) /* trailing space */
748 {
749 --key_len, --new_key;
750 if (bad_character == 0)
751 bad_character = 32;
752 }
753
754 /* Terminate the keyword */
755 *new_key = 0;
756
757 if (key_len == 0)
758 return 0;
759
760 #ifdef PNG_WARNINGS_SUPPORTED
761 /* Try to only output one warning per keyword: */
762 if (*key != 0) /* keyword too long */
763 png_warning(png_ptr, "keyword truncated");
764
765 else if (bad_character != 0)
766 {
767 PNG_WARNING_PARAMETERS(p)
768
769 png_warning_parameter(p, 1, orig_key);
770 png_warning_parameter_signed(p, 2, PNG_NUMBER_FORMAT_02x, bad_character);
771
772 png_formatted_warning(png_ptr, p, "keyword \"@1\": bad character '0x@2'");
773 }
774 #endif /* WARNINGS */
775
776 return key_len;
777 }
778 #endif /* WRITE_TEXT || WRITE_pCAL || WRITE_iCCP || WRITE_sPLT */
779
780 /* Write the IHDR chunk, and update the png_struct with the necessary
781 * information. Note that the rest of this code depends upon this
782 * information being correct.
783 */
784 void /* PRIVATE */
785 png_write_IHDR(png_structrp png_ptr, png_uint_32 width, png_uint_32 height,
786 int bit_depth, int color_type, int compression_type, int filter_type,
787 int interlace_type)
788 {
789 png_byte buf[13]; /* Buffer to store the IHDR info */
790
791 png_debug(1, "in png_write_IHDR");
792
793 /* Check that we have valid input data from the application info */
794 switch (color_type)
795 {
796 case PNG_COLOR_TYPE_GRAY:
797 switch (bit_depth)
798 {
799 case 1:
800 case 2:
801 case 4:
802 case 8:
803 #ifdef PNG_WRITE_16BIT_SUPPORTED
804 case 16:
805 #endif
806 png_ptr->channels = 1; break;
807
808 default:
809 png_error(png_ptr,
810 "Invalid bit depth for grayscale image");
811 }
812 break;
813
814 case PNG_COLOR_TYPE_RGB:
815 #ifdef PNG_WRITE_16BIT_SUPPORTED
816 if (bit_depth != 8 && bit_depth != 16)
817 #else
818 if (bit_depth != 8)
819 #endif
820 png_error(png_ptr, "Invalid bit depth for RGB image");
821
822 png_ptr->channels = 3;
823 break;
824
825 case PNG_COLOR_TYPE_PALETTE:
826 switch (bit_depth)
827 {
828 case 1:
829 case 2:
830 case 4:
831 case 8:
832 png_ptr->channels = 1;
833 break;
834
835 default:
836 png_error(png_ptr, "Invalid bit depth for paletted image");
837 }
838 break;
839
840 case PNG_COLOR_TYPE_GRAY_ALPHA:
841 if (bit_depth != 8 && bit_depth != 16)
842 png_error(png_ptr, "Invalid bit depth for grayscale+alpha image");
843
844 png_ptr->channels = 2;
845 break;
846
847 case PNG_COLOR_TYPE_RGB_ALPHA:
848 #ifdef PNG_WRITE_16BIT_SUPPORTED
849 if (bit_depth != 8 && bit_depth != 16)
850 #else
851 if (bit_depth != 8)
852 #endif
853 png_error(png_ptr, "Invalid bit depth for RGBA image");
854
855 png_ptr->channels = 4;
856 break;
857
858 default:
859 png_error(png_ptr, "Invalid image color type specified");
860 }
861
862 if (compression_type != PNG_COMPRESSION_TYPE_BASE)
863 {
864 png_warning(png_ptr, "Invalid compression type specified");
865 compression_type = PNG_COMPRESSION_TYPE_BASE;
866 }
867
868 /* Write filter_method 64 (intrapixel differencing) only if
869 * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
870 * 2. Libpng did not write a PNG signature (this filter_method is only
871 * used in PNG datastreams that are embedded in MNG datastreams) and
872 * 3. The application called png_permit_mng_features with a mask that
873 * included PNG_FLAG_MNG_FILTER_64 and
874 * 4. The filter_method is 64 and
875 * 5. The color_type is RGB or RGBA
876 */
877 if (
878 #ifdef PNG_MNG_FEATURES_SUPPORTED
879 !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
880 ((png_ptr->mode & PNG_HAVE_PNG_SIGNATURE) == 0) &&
881 (color_type == PNG_COLOR_TYPE_RGB ||
882 color_type == PNG_COLOR_TYPE_RGB_ALPHA) &&
883 (filter_type == PNG_INTRAPIXEL_DIFFERENCING)) &&
884 #endif
885 filter_type != PNG_FILTER_TYPE_BASE)
886 {
887 png_warning(png_ptr, "Invalid filter type specified");
888 filter_type = PNG_FILTER_TYPE_BASE;
889 }
890
891 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
892 if (interlace_type != PNG_INTERLACE_NONE &&
893 interlace_type != PNG_INTERLACE_ADAM7)
894 {
895 png_warning(png_ptr, "Invalid interlace type specified");
896 interlace_type = PNG_INTERLACE_ADAM7;
897 }
898 #else
899 interlace_type=PNG_INTERLACE_NONE;
900 #endif
901
902 /* Save the relevant information */
903 png_ptr->bit_depth = (png_byte)bit_depth;
904 png_ptr->color_type = (png_byte)color_type;
905 png_ptr->interlaced = (png_byte)interlace_type;
906 #ifdef PNG_MNG_FEATURES_SUPPORTED
907 png_ptr->filter_type = (png_byte)filter_type;
908 #endif
909 png_ptr->compression_type = (png_byte)compression_type;
910 png_ptr->width = width;
911 png_ptr->height = height;
912
913 png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels);
914 png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, width);
915 /* Set the usr info, so any transformations can modify it */
916 png_ptr->usr_width = png_ptr->width;
917 png_ptr->usr_bit_depth = png_ptr->bit_depth;
918 png_ptr->usr_channels = png_ptr->channels;
919
920 /* Pack the header information into the buffer */
921 png_save_uint_32(buf, width);
922 png_save_uint_32(buf + 4, height);
923 buf[8] = (png_byte)bit_depth;
924 buf[9] = (png_byte)color_type;
925 buf[10] = (png_byte)compression_type;
926 buf[11] = (png_byte)filter_type;
927 buf[12] = (png_byte)interlace_type;
928
929 /* Write the chunk */
930 png_write_complete_chunk(png_ptr, png_IHDR, buf, (png_size_t)13);
931
932 if ((png_ptr->do_filter) == PNG_NO_FILTERS)
933 {
934 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||
935 png_ptr->bit_depth < 8)
936 png_ptr->do_filter = PNG_FILTER_NONE;
937
938 else
939 png_ptr->do_filter = PNG_ALL_FILTERS;
940 }
941
942 png_ptr->mode = PNG_HAVE_IHDR; /* not READY_FOR_ZTXT */
943 }
944
945 /* Write the palette. We are careful not to trust png_color to be in the
946 * correct order for PNG, so people can redefine it to any convenient
947 * structure.
948 */
949 void /* PRIVATE */
950 png_write_PLTE(png_structrp png_ptr, png_const_colorp palette,
951 png_uint_32 num_pal)
952 {
953 png_uint_32 max_palette_length, i;
954 png_const_colorp pal_ptr;
955 png_byte buf[3];
956
957 png_debug(1, "in png_write_PLTE");
958
959 max_palette_length = (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ?
960 (1 << png_ptr->bit_depth) : PNG_MAX_PALETTE_LENGTH;
961
962 if ((
963 #ifdef PNG_MNG_FEATURES_SUPPORTED
964 (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0 &&
965 #endif
966 num_pal == 0) || num_pal > max_palette_length)
967 {
968 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
969 {
970 png_error(png_ptr, "Invalid number of colors in palette");
971 }
972
973 else
974 {
975 png_warning(png_ptr, "Invalid number of colors in palette");
976 return;
977 }
978 }
979
980 if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
981 {
982 png_warning(png_ptr,
983 "Ignoring request to write a PLTE chunk in grayscale PNG");
984
985 return;
986 }
987
988 png_ptr->num_palette = (png_uint_16)num_pal;
989 png_debug1(3, "num_palette = %d", png_ptr->num_palette);
990
991 png_write_chunk_header(png_ptr, png_PLTE, (png_uint_32)(num_pal * 3));
992 #ifdef PNG_POINTER_INDEXING_SUPPORTED
993
994 for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++)
995 {
996 buf[0] = pal_ptr->red;
997 buf[1] = pal_ptr->green;
998 buf[2] = pal_ptr->blue;
999 png_write_chunk_data(png_ptr, buf, (png_size_t)3);
1000 }
1001
1002 #else
1003 /* This is a little slower but some buggy compilers need to do this
1004 * instead
1005 */
1006 pal_ptr=palette;
1007
1008 for (i = 0; i < num_pal; i++)
1009 {
1010 buf[0] = pal_ptr[i].red;
1011 buf[1] = pal_ptr[i].green;
1012 buf[2] = pal_ptr[i].blue;
1013 png_write_chunk_data(png_ptr, buf, (png_size_t)3);
1014 }
1015
1016 #endif
1017 png_write_chunk_end(png_ptr);
1018 png_ptr->mode |= PNG_HAVE_PLTE;
1019 }
1020
1021 /* This is similar to png_text_compress, above, except that it does not require
1022 * all of the data at once and, instead of buffering the compressed result,
1023 * writes it as IDAT chunks. Unlike png_text_compress it *can* png_error out
1024 * because it calls the write interface. As a result it does its own error
1025 * reporting and does not return an error code. In the event of error it will
1026 * just call png_error. The input data length may exceed 32-bits. The 'flush'
1027 * parameter is exactly the same as that to deflate, with the following
1028 * meanings:
1029 *
1030 * Z_NO_FLUSH: normal incremental output of compressed data
1031 * Z_SYNC_FLUSH: do a SYNC_FLUSH, used by png_write_flush
1032 * Z_FINISH: this is the end of the input, do a Z_FINISH and clean up
1033 *
1034 * The routine manages the acquire and release of the png_ptr->zstream by
1035 * checking and (at the end) clearing png_ptr->zowner; it does some sanity
1036 * checks on the 'mode' flags while doing this.
1037 */
1038 void /* PRIVATE */
1039 png_compress_IDAT(png_structrp png_ptr, png_const_bytep input,
1040 png_alloc_size_t input_len, int flush)
1041 {
1042 if (png_ptr->zowner != png_IDAT)
1043 {
1044 /* First time. Ensure we have a temporary buffer for compression and
1045 * trim the buffer list if it has more than one entry to free memory.
1046 * If 'WRITE_COMPRESSED_TEXT' is not set the list will never have been
1047 * created at this point, but the check here is quick and safe.
1048 */
1049 if (png_ptr->zbuffer_list == NULL)
1050 {
1051 png_ptr->zbuffer_list = png_voidcast(png_compression_bufferp,
1052 png_malloc(png_ptr, PNG_COMPRESSION_BUFFER_SIZE(png_ptr)));
1053 png_ptr->zbuffer_list->next = NULL;
1054 }
1055
1056 else
1057 png_free_buffer_list(png_ptr, &png_ptr->zbuffer_list->next);
1058
1059 /* It is a terminal error if we can't claim the zstream. */
1060 if (png_deflate_claim(png_ptr, png_IDAT, png_image_size(png_ptr)) != Z_OK)
1061 png_error(png_ptr, png_ptr->zstream.msg);
1062
1063 /* The output state is maintained in png_ptr->zstream, so it must be
1064 * initialized here after the claim.
1065 */
1066 png_ptr->zstream.next_out = png_ptr->zbuffer_list->output;
1067 png_ptr->zstream.avail_out = png_ptr->zbuffer_size;
1068 }
1069
1070 /* Now loop reading and writing until all the input is consumed or an error
1071 * terminates the operation. The _out values are maintained across calls to
1072 * this function, but the input must be reset each time.
1073 */
1074 png_ptr->zstream.next_in = PNGZ_INPUT_CAST(input);
1075 png_ptr->zstream.avail_in = 0; /* set below */
1076 for (;;)
1077 {
1078 int ret;
1079
1080 /* INPUT: from the row data */
1081 uInt avail = ZLIB_IO_MAX;
1082
1083 if (avail > input_len)
1084 avail = (uInt)input_len; /* safe because of the check */
1085
1086 png_ptr->zstream.avail_in = avail;
1087 input_len -= avail;
1088
1089 ret = deflate(&png_ptr->zstream, input_len > 0 ? Z_NO_FLUSH : flush);
1090
1091 /* Include as-yet unconsumed input */
1092 input_len += png_ptr->zstream.avail_in;
1093 png_ptr->zstream.avail_in = 0;
1094
1095 /* OUTPUT: write complete IDAT chunks when avail_out drops to zero. Note
1096 * that these two zstream fields are preserved across the calls, therefore
1097 * there is no need to set these up on entry to the loop.
1098 */
1099 if (png_ptr->zstream.avail_out == 0)
1100 {
1101 png_bytep data = png_ptr->zbuffer_list->output;
1102 uInt size = png_ptr->zbuffer_size;
1103
1104 /* Write an IDAT containing the data then reset the buffer. The
1105 * first IDAT may need deflate header optimization.
1106 */
1107 #ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
1108 if ((png_ptr->mode & PNG_HAVE_IDAT) == 0 &&
1109 png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
1110 optimize_cmf(data, png_image_size(png_ptr));
1111 #endif
1112
1113 png_write_complete_chunk(png_ptr, png_IDAT, data, size);
1114 png_ptr->mode |= PNG_HAVE_IDAT;
1115
1116 png_ptr->zstream.next_out = data;
1117 png_ptr->zstream.avail_out = size;
1118
1119 /* For SYNC_FLUSH or FINISH it is essential to keep calling zlib with
1120 * the same flush parameter until it has finished output, for NO_FLUSH
1121 * it doesn't matter.
1122 */
1123 if (ret == Z_OK && flush != Z_NO_FLUSH)
1124 continue;
1125 }
1126
1127 /* The order of these checks doesn't matter much; it just affects which
1128 * possible error might be detected if multiple things go wrong at once.
1129 */
1130 if (ret == Z_OK) /* most likely return code! */
1131 {
1132 /* If all the input has been consumed then just return. If Z_FINISH
1133 * was used as the flush parameter something has gone wrong if we get
1134 * here.
1135 */
1136 if (input_len == 0)
1137 {
1138 if (flush == Z_FINISH)
1139 png_error(png_ptr, "Z_OK on Z_FINISH with output space");
1140
1141 return;
1142 }
1143 }
1144
1145 else if (ret == Z_STREAM_END && flush == Z_FINISH)
1146 {
1147 /* This is the end of the IDAT data; any pending output must be
1148 * flushed. For small PNG files we may still be at the beginning.
1149 */
1150 png_bytep data = png_ptr->zbuffer_list->output;
1151 uInt size = png_ptr->zbuffer_size - png_ptr->zstream.avail_out;
1152
1153 #ifdef PNG_WRITE_OPTIMIZE_CMF_SUPPORTED
1154 if ((png_ptr->mode & PNG_HAVE_IDAT) == 0 &&
1155 png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
1156 optimize_cmf(data, png_image_size(png_ptr));
1157 #endif
1158
1159 png_write_complete_chunk(png_ptr, png_IDAT, data, size);
1160 png_ptr->zstream.avail_out = 0;
1161 png_ptr->zstream.next_out = NULL;
1162 png_ptr->mode |= PNG_HAVE_IDAT | PNG_AFTER_IDAT;
1163
1164 png_ptr->zowner = 0; /* Release the stream */
1165 return;
1166 }
1167
1168 else
1169 {
1170 /* This is an error condition. */
1171 png_zstream_error(png_ptr, ret);
1172 png_error(png_ptr, png_ptr->zstream.msg);
1173 }
1174 }
1175 }
1176
1177 /* Write an IEND chunk */
1178 void /* PRIVATE */
1179 png_write_IEND(png_structrp png_ptr)
1180 {
1181 png_debug(1, "in png_write_IEND");
1182
1183 png_write_complete_chunk(png_ptr, png_IEND, NULL, (png_size_t)0);
1184 png_ptr->mode |= PNG_HAVE_IEND;
1185 }
1186
1187 #ifdef PNG_WRITE_gAMA_SUPPORTED
1188 /* Write a gAMA chunk */
1189 void /* PRIVATE */
1190 png_write_gAMA_fixed(png_structrp png_ptr, png_fixed_point file_gamma)
1191 {
1192 png_byte buf[4];
1193
1194 png_debug(1, "in png_write_gAMA");
1195
1196 /* file_gamma is saved in 1/100,000ths */
1197 png_save_uint_32(buf, (png_uint_32)file_gamma);
1198 png_write_complete_chunk(png_ptr, png_gAMA, buf, (png_size_t)4);
1199 }
1200 #endif
1201
1202 #ifdef PNG_WRITE_sRGB_SUPPORTED
1203 /* Write a sRGB chunk */
1204 void /* PRIVATE */
1205 png_write_sRGB(png_structrp png_ptr, int srgb_intent)
1206 {
1207 png_byte buf[1];
1208
1209 png_debug(1, "in png_write_sRGB");
1210
1211 if (srgb_intent >= PNG_sRGB_INTENT_LAST)
1212 png_warning(png_ptr,
1213 "Invalid sRGB rendering intent specified");
1214
1215 buf[0]=(png_byte)srgb_intent;
1216 png_write_complete_chunk(png_ptr, png_sRGB, buf, (png_size_t)1);
1217 }
1218 #endif
1219
1220 #ifdef PNG_WRITE_iCCP_SUPPORTED
1221 /* Write an iCCP chunk */
1222 void /* PRIVATE */
1223 png_write_iCCP(png_structrp png_ptr, png_const_charp name,
1224 png_const_bytep profile)
1225 {
1226 png_uint_32 name_len;
1227 png_uint_32 profile_len;
1228 png_byte new_name[81]; /* 1 byte for the compression byte */
1229 compression_state comp;
1230 png_uint_32 temp;
1231
1232 png_debug(1, "in png_write_iCCP");
1233
1234 /* These are all internal problems: the profile should have been checked
1235 * before when it was stored.
1236 */
1237 if (profile == NULL)
1238 png_error(png_ptr, "No profile for iCCP chunk"); /* internal error */
1239
1240 profile_len = png_get_uint_32(profile);
1241
1242 if (profile_len < 132)
1243 png_error(png_ptr, "ICC profile too short");
1244
1245 temp = (png_uint_32) (*(profile+8));
1246 if (temp > 3 && (profile_len & 0x03))
1247 png_error(png_ptr, "ICC profile length invalid (not a multiple of 4)");
1248
1249 {
1250 png_uint_32 embedded_profile_len = png_get_uint_32(profile);
1251
1252 if (profile_len != embedded_profile_len)
1253 png_error(png_ptr, "Profile length does not match profile");
1254 }
1255
1256 name_len = png_check_keyword(png_ptr, name, new_name);
1257
1258 if (name_len == 0)
1259 png_error(png_ptr, "iCCP: invalid keyword");
1260
1261 new_name[++name_len] = PNG_COMPRESSION_TYPE_BASE;
1262
1263 /* Make sure we include the NULL after the name and the compression type */
1264 ++name_len;
1265
1266 png_text_compress_init(&comp, profile, profile_len);
1267
1268 /* Allow for keyword terminator and compression byte */
1269 if (png_text_compress(png_ptr, png_iCCP, &comp, name_len) != Z_OK)
1270 png_error(png_ptr, png_ptr->zstream.msg);
1271
1272 png_write_chunk_header(png_ptr, png_iCCP, name_len + comp.output_len);
1273
1274 png_write_chunk_data(png_ptr, new_name, name_len);
1275
1276 png_write_compressed_data_out(png_ptr, &comp);
1277
1278 png_write_chunk_end(png_ptr);
1279 }
1280 #endif
1281
1282 #ifdef PNG_WRITE_sPLT_SUPPORTED
1283 /* Write a sPLT chunk */
1284 void /* PRIVATE */
1285 png_write_sPLT(png_structrp png_ptr, png_const_sPLT_tp spalette)
1286 {
1287 png_uint_32 name_len;
1288 png_byte new_name[80];
1289 png_byte entrybuf[10];
1290 png_size_t entry_size = (spalette->depth == 8 ? 6 : 10);
1291 png_size_t palette_size = entry_size * spalette->nentries;
1292 png_sPLT_entryp ep;
1293 #ifndef PNG_POINTER_INDEXING_SUPPORTED
1294 int i;
1295 #endif
1296
1297 png_debug(1, "in png_write_sPLT");
1298
1299 name_len = png_check_keyword(png_ptr, spalette->name, new_name);
1300
1301 if (name_len == 0)
1302 png_error(png_ptr, "sPLT: invalid keyword");
1303
1304 /* Make sure we include the NULL after the name */
1305 png_write_chunk_header(png_ptr, png_sPLT,
1306 (png_uint_32)(name_len + 2 + palette_size));
1307
1308 png_write_chunk_data(png_ptr, (png_bytep)new_name,
1309 (png_size_t)(name_len + 1));
1310
1311 png_write_chunk_data(png_ptr, &spalette->depth, (png_size_t)1);
1312
1313 /* Loop through each palette entry, writing appropriately */
1314 #ifdef PNG_POINTER_INDEXING_SUPPORTED
1315 for (ep = spalette->entries; ep<spalette->entries + spalette->nentries; ep++)
1316 {
1317 if (spalette->depth == 8)
1318 {
1319 entrybuf[0] = (png_byte)ep->red;
1320 entrybuf[1] = (png_byte)ep->green;
1321 entrybuf[2] = (png_byte)ep->blue;
1322 entrybuf[3] = (png_byte)ep->alpha;
1323 png_save_uint_16(entrybuf + 4, ep->frequency);
1324 }
1325
1326 else
1327 {
1328 png_save_uint_16(entrybuf + 0, ep->red);
1329 png_save_uint_16(entrybuf + 2, ep->green);
1330 png_save_uint_16(entrybuf + 4, ep->blue);
1331 png_save_uint_16(entrybuf + 6, ep->alpha);
1332 png_save_uint_16(entrybuf + 8, ep->frequency);
1333 }
1334
1335 png_write_chunk_data(png_ptr, entrybuf, entry_size);
1336 }
1337 #else
1338 ep=spalette->entries;
1339 for (i = 0; i>spalette->nentries; i++)
1340 {
1341 if (spalette->depth == 8)
1342 {
1343 entrybuf[0] = (png_byte)ep[i].red;
1344 entrybuf[1] = (png_byte)ep[i].green;
1345 entrybuf[2] = (png_byte)ep[i].blue;
1346 entrybuf[3] = (png_byte)ep[i].alpha;
1347 png_save_uint_16(entrybuf + 4, ep[i].frequency);
1348 }
1349
1350 else
1351 {
1352 png_save_uint_16(entrybuf + 0, ep[i].red);
1353 png_save_uint_16(entrybuf + 2, ep[i].green);
1354 png_save_uint_16(entrybuf + 4, ep[i].blue);
1355 png_save_uint_16(entrybuf + 6, ep[i].alpha);
1356 png_save_uint_16(entrybuf + 8, ep[i].frequency);
1357 }
1358
1359 png_write_chunk_data(png_ptr, entrybuf, entry_size);
1360 }
1361 #endif
1362
1363 png_write_chunk_end(png_ptr);
1364 }
1365 #endif
1366
1367 #ifdef PNG_WRITE_sBIT_SUPPORTED
1368 /* Write the sBIT chunk */
1369 void /* PRIVATE */
1370 png_write_sBIT(png_structrp png_ptr, png_const_color_8p sbit, int color_type)
1371 {
1372 png_byte buf[4];
1373 png_size_t size;
1374
1375 png_debug(1, "in png_write_sBIT");
1376
1377 /* Make sure we don't depend upon the order of PNG_COLOR_8 */
1378 if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
1379 {
1380 png_byte maxbits;
1381
1382 maxbits = (png_byte)(color_type==PNG_COLOR_TYPE_PALETTE ? 8 :
1383 png_ptr->usr_bit_depth);
1384
1385 if (sbit->red == 0 || sbit->red > maxbits ||
1386 sbit->green == 0 || sbit->green > maxbits ||
1387 sbit->blue == 0 || sbit->blue > maxbits)
1388 {
1389 png_warning(png_ptr, "Invalid sBIT depth specified");
1390 return;
1391 }
1392
1393 buf[0] = sbit->red;
1394 buf[1] = sbit->green;
1395 buf[2] = sbit->blue;
1396 size = 3;
1397 }
1398
1399 else
1400 {
1401 if (sbit->gray == 0 || sbit->gray > png_ptr->usr_bit_depth)
1402 {
1403 png_warning(png_ptr, "Invalid sBIT depth specified");
1404 return;
1405 }
1406
1407 buf[0] = sbit->gray;
1408 size = 1;
1409 }
1410
1411 if ((color_type & PNG_COLOR_MASK_ALPHA) != 0)
1412 {
1413 if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth)
1414 {
1415 png_warning(png_ptr, "Invalid sBIT depth specified");
1416 return;
1417 }
1418
1419 buf[size++] = sbit->alpha;
1420 }
1421
1422 png_write_complete_chunk(png_ptr, png_sBIT, buf, size);
1423 }
1424 #endif
1425
1426 #ifdef PNG_WRITE_cHRM_SUPPORTED
1427 /* Write the cHRM chunk */
1428 void /* PRIVATE */
1429 png_write_cHRM_fixed(png_structrp png_ptr, const png_xy *xy)
1430 {
1431 png_byte buf[32];
1432
1433 png_debug(1, "in png_write_cHRM");
1434
1435 /* Each value is saved in 1/100,000ths */
1436 png_save_int_32(buf, xy->whitex);
1437 png_save_int_32(buf + 4, xy->whitey);
1438
1439 png_save_int_32(buf + 8, xy->redx);
1440 png_save_int_32(buf + 12, xy->redy);
1441
1442 png_save_int_32(buf + 16, xy->greenx);
1443 png_save_int_32(buf + 20, xy->greeny);
1444
1445 png_save_int_32(buf + 24, xy->bluex);
1446 png_save_int_32(buf + 28, xy->bluey);
1447
1448 png_write_complete_chunk(png_ptr, png_cHRM, buf, 32);
1449 }
1450 #endif
1451
1452 #ifdef PNG_WRITE_tRNS_SUPPORTED
1453 /* Write the tRNS chunk */
1454 void /* PRIVATE */
1455 png_write_tRNS(png_structrp png_ptr, png_const_bytep trans_alpha,
1456 png_const_color_16p tran, int num_trans, int color_type)
1457 {
1458 png_byte buf[6];
1459
1460 png_debug(1, "in png_write_tRNS");
1461
1462 if (color_type == PNG_COLOR_TYPE_PALETTE)
1463 {
1464 if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette)
1465 {
1466 png_app_warning(png_ptr,
1467 "Invalid number of transparent colors specified");
1468 return;
1469 }
1470
1471 /* Write the chunk out as it is */
1472 png_write_complete_chunk(png_ptr, png_tRNS, trans_alpha,
1473 (png_size_t)num_trans);
1474 }
1475
1476 else if (color_type == PNG_COLOR_TYPE_GRAY)
1477 {
1478 /* One 16-bit value */
1479 if (tran->gray >= (1 << png_ptr->bit_depth))
1480 {
1481 png_app_warning(png_ptr,
1482 "Ignoring attempt to write tRNS chunk out-of-range for bit_depth");
1483
1484 return;
1485 }
1486
1487 png_save_uint_16(buf, tran->gray);
1488 png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)2);
1489 }
1490
1491 else if (color_type == PNG_COLOR_TYPE_RGB)
1492 {
1493 /* Three 16-bit values */
1494 png_save_uint_16(buf, tran->red);
1495 png_save_uint_16(buf + 2, tran->green);
1496 png_save_uint_16(buf + 4, tran->blue);
1497 #ifdef PNG_WRITE_16BIT_SUPPORTED
1498 if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]) != 0)
1499 #else
1500 if ((buf[0] | buf[2] | buf[4]) != 0)
1501 #endif
1502 {
1503 png_app_warning(png_ptr,
1504 "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8");
1505 return;
1506 }
1507
1508 png_write_complete_chunk(png_ptr, png_tRNS, buf, (png_size_t)6);
1509 }
1510
1511 else
1512 {
1513 png_app_warning(png_ptr, "Can't write tRNS with an alpha channel");
1514 }
1515 }
1516 #endif
1517
1518 #ifdef PNG_WRITE_bKGD_SUPPORTED
1519 /* Write the background chunk */
1520 void /* PRIVATE */
1521 png_write_bKGD(png_structrp png_ptr, png_const_color_16p back, int color_type)
1522 {
1523 png_byte buf[6];
1524
1525 png_debug(1, "in png_write_bKGD");
1526
1527 if (color_type == PNG_COLOR_TYPE_PALETTE)
1528 {
1529 if (
1530 #ifdef PNG_MNG_FEATURES_SUPPORTED
1531 (png_ptr->num_palette != 0 ||
1532 (png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) == 0) &&
1533 #endif
1534 back->index >= png_ptr->num_palette)
1535 {
1536 png_warning(png_ptr, "Invalid background palette index");
1537 return;
1538 }
1539
1540 buf[0] = back->index;
1541 png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)1);
1542 }
1543
1544 else if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
1545 {
1546 png_save_uint_16(buf, back->red);
1547 png_save_uint_16(buf + 2, back->green);
1548 png_save_uint_16(buf + 4, back->blue);
1549 #ifdef PNG_WRITE_16BIT_SUPPORTED
1550 if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]) != 0)
1551 #else
1552 if ((buf[0] | buf[2] | buf[4]) != 0)
1553 #endif
1554 {
1555 png_warning(png_ptr,
1556 "Ignoring attempt to write 16-bit bKGD chunk when bit_depth is 8");
1557
1558 return;
1559 }
1560
1561 png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)6);
1562 }
1563
1564 else
1565 {
1566 if (back->gray >= (1 << png_ptr->bit_depth))
1567 {
1568 png_warning(png_ptr,
1569 "Ignoring attempt to write bKGD chunk out-of-range for bit_depth");
1570
1571 return;
1572 }
1573
1574 png_save_uint_16(buf, back->gray);
1575 png_write_complete_chunk(png_ptr, png_bKGD, buf, (png_size_t)2);
1576 }
1577 }
1578 #endif
1579
1580 #ifdef PNG_WRITE_hIST_SUPPORTED
1581 /* Write the histogram */
1582 void /* PRIVATE */
1583 png_write_hIST(png_structrp png_ptr, png_const_uint_16p hist, int num_hist)
1584 {
1585 int i;
1586 png_byte buf[3];
1587
1588 png_debug(1, "in png_write_hIST");
1589
1590 if (num_hist > (int)png_ptr->num_palette)
1591 {
1592 png_debug2(3, "num_hist = %d, num_palette = %d", num_hist,
1593 png_ptr->num_palette);
1594
1595 png_warning(png_ptr, "Invalid number of histogram entries specified");
1596 return;
1597 }
1598
1599 png_write_chunk_header(png_ptr, png_hIST, (png_uint_32)(num_hist * 2));
1600
1601 for (i = 0; i < num_hist; i++)
1602 {
1603 png_save_uint_16(buf, hist[i]);
1604 png_write_chunk_data(png_ptr, buf, (png_size_t)2);
1605 }
1606
1607 png_write_chunk_end(png_ptr);
1608 }
1609 #endif
1610
1611 #ifdef PNG_WRITE_tEXt_SUPPORTED
1612 /* Write a tEXt chunk */
1613 void /* PRIVATE */
1614 png_write_tEXt(png_structrp png_ptr, png_const_charp key, png_const_charp text,
1615 png_size_t text_len)
1616 {
1617 png_uint_32 key_len;
1618 png_byte new_key[80];
1619
1620 png_debug(1, "in png_write_tEXt");
1621
1622 key_len = png_check_keyword(png_ptr, key, new_key);
1623
1624 if (key_len == 0)
1625 png_error(png_ptr, "tEXt: invalid keyword");
1626
1627 if (text == NULL || *text == '\0')
1628 text_len = 0;
1629
1630 else
1631 text_len = strlen(text);
1632
1633 if (text_len > PNG_UINT_31_MAX - (key_len+1))
1634 png_error(png_ptr, "tEXt: text too long");
1635
1636 /* Make sure we include the 0 after the key */
1637 png_write_chunk_header(png_ptr, png_tEXt,
1638 (png_uint_32)/*checked above*/(key_len + text_len + 1));
1639 /*
1640 * We leave it to the application to meet PNG-1.0 requirements on the
1641 * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of
1642 * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them.
1643 * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
1644 */
1645 png_write_chunk_data(png_ptr, new_key, key_len + 1);
1646
1647 if (text_len != 0)
1648 png_write_chunk_data(png_ptr, (png_const_bytep)text, text_len);
1649
1650 png_write_chunk_end(png_ptr);
1651 }
1652 #endif
1653
1654 #ifdef PNG_WRITE_zTXt_SUPPORTED
1655 /* Write a compressed text chunk */
1656 void /* PRIVATE */
1657 png_write_zTXt(png_structrp png_ptr, png_const_charp key, png_const_charp text,
1658 int compression)
1659 {
1660 png_uint_32 key_len;
1661 png_byte new_key[81];
1662 compression_state comp;
1663
1664 png_debug(1, "in png_write_zTXt");
1665
1666 if (compression == PNG_TEXT_COMPRESSION_NONE)
1667 {
1668 png_write_tEXt(png_ptr, key, text, 0);
1669 return;
1670 }
1671
1672 if (compression != PNG_TEXT_COMPRESSION_zTXt)
1673 png_error(png_ptr, "zTXt: invalid compression type");
1674
1675 key_len = png_check_keyword(png_ptr, key, new_key);
1676
1677 if (key_len == 0)
1678 png_error(png_ptr, "zTXt: invalid keyword");
1679
1680 /* Add the compression method and 1 for the keyword separator. */
1681 new_key[++key_len] = PNG_COMPRESSION_TYPE_BASE;
1682 ++key_len;
1683
1684 /* Compute the compressed data; do it now for the length */
1685 png_text_compress_init(&comp, (png_const_bytep)text,
1686 text == NULL ? 0 : strlen(text));
1687
1688 if (png_text_compress(png_ptr, png_zTXt, &comp, key_len) != Z_OK)
1689 png_error(png_ptr, png_ptr->zstream.msg);
1690
1691 /* Write start of chunk */
1692 png_write_chunk_header(png_ptr, png_zTXt, key_len + comp.output_len);
1693
1694 /* Write key */
1695 png_write_chunk_data(png_ptr, new_key, key_len);
1696
1697 /* Write the compressed data */
1698 png_write_compressed_data_out(png_ptr, &comp);
1699
1700 /* Close the chunk */
1701 png_write_chunk_end(png_ptr);
1702 }
1703 #endif
1704
1705 #ifdef PNG_WRITE_iTXt_SUPPORTED
1706 /* Write an iTXt chunk */
1707 void /* PRIVATE */
1708 png_write_iTXt(png_structrp png_ptr, int compression, png_const_charp key,
1709 png_const_charp lang, png_const_charp lang_key, png_const_charp text)
1710 {
1711 png_uint_32 key_len, prefix_len;
1712 png_size_t lang_len, lang_key_len;
1713 png_byte new_key[82];
1714 compression_state comp;
1715
1716 png_debug(1, "in png_write_iTXt");
1717
1718 key_len = png_check_keyword(png_ptr, key, new_key);
1719
1720 if (key_len == 0)
1721 png_error(png_ptr, "iTXt: invalid keyword");
1722
1723 /* Set the compression flag */
1724 switch (compression)
1725 {
1726 case PNG_ITXT_COMPRESSION_NONE:
1727 case PNG_TEXT_COMPRESSION_NONE:
1728 compression = new_key[++key_len] = 0; /* no compression */
1729 break;
1730
1731 case PNG_TEXT_COMPRESSION_zTXt:
1732 case PNG_ITXT_COMPRESSION_zTXt:
1733 compression = new_key[++key_len] = 1; /* compressed */
1734 break;
1735
1736 default:
1737 png_error(png_ptr, "iTXt: invalid compression");
1738 }
1739
1740 new_key[++key_len] = PNG_COMPRESSION_TYPE_BASE;
1741 ++key_len; /* for the keywod separator */
1742
1743 /* We leave it to the application to meet PNG-1.0 requirements on the
1744 * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of
1745 * any non-Latin-1 characters except for NEWLINE. ISO PNG, however,
1746 * specifies that the text is UTF-8 and this really doesn't require any
1747 * checking.
1748 *
1749 * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
1750 *
1751 * TODO: validate the language tag correctly (see the spec.)
1752 */
1753 if (lang == NULL) lang = ""; /* empty language is valid */
1754 lang_len = strlen(lang)+1;
1755 if (lang_key == NULL) lang_key = ""; /* may be empty */
1756 lang_key_len = strlen(lang_key)+1;
1757 if (text == NULL) text = ""; /* may be empty */
1758
1759 prefix_len = key_len;
1760 if (lang_len > PNG_UINT_31_MAX-prefix_len)
1761 prefix_len = PNG_UINT_31_MAX;
1762 else
1763 prefix_len = (png_uint_32)(prefix_len + lang_len);
1764
1765 if (lang_key_len > PNG_UINT_31_MAX-prefix_len)
1766 prefix_len = PNG_UINT_31_MAX;
1767 else
1768 prefix_len = (png_uint_32)(prefix_len + lang_key_len);
1769
1770 png_text_compress_init(&comp, (png_const_bytep)text, strlen(text));
1771
1772 if (compression != 0)
1773 {
1774 if (png_text_compress(png_ptr, png_iTXt, &comp, prefix_len) != Z_OK)
1775 png_error(png_ptr, png_ptr->zstream.msg);
1776 }
1777
1778 else
1779 {
1780 if (comp.input_len > PNG_UINT_31_MAX-prefix_len)
1781 png_error(png_ptr, "iTXt: uncompressed text too long");
1782
1783 /* So the string will fit in a chunk: */
1784 comp.output_len = (png_uint_32)/*SAFE*/comp.input_len;
1785 }
1786
1787 png_write_chunk_header(png_ptr, png_iTXt, comp.output_len + prefix_len);
1788
1789 png_write_chunk_data(png_ptr, new_key, key_len);
1790
1791 png_write_chunk_data(png_ptr, (png_const_bytep)lang, lang_len);
1792
1793 png_write_chunk_data(png_ptr, (png_const_bytep)lang_key, lang_key_len);
1794
1795 if (compression != 0)
1796 png_write_compressed_data_out(png_ptr, &comp);
1797
1798 else
1799 png_write_chunk_data(png_ptr, (png_const_bytep)text, comp.output_len);
1800
1801 png_write_chunk_end(png_ptr);
1802 }
1803 #endif
1804
1805 #ifdef PNG_WRITE_oFFs_SUPPORTED
1806 /* Write the oFFs chunk */
1807 void /* PRIVATE */
1808 png_write_oFFs(png_structrp png_ptr, png_int_32 x_offset, png_int_32 y_offset,
1809 int unit_type)
1810 {
1811 png_byte buf[9];
1812
1813 png_debug(1, "in png_write_oFFs");
1814
1815 if (unit_type >= PNG_OFFSET_LAST)
1816 png_warning(png_ptr, "Unrecognized unit type for oFFs chunk");
1817
1818 png_save_int_32(buf, x_offset);
1819 png_save_int_32(buf + 4, y_offset);
1820 buf[8] = (png_byte)unit_type;
1821
1822 png_write_complete_chunk(png_ptr, png_oFFs, buf, (png_size_t)9);
1823 }
1824 #endif
1825 #ifdef PNG_WRITE_pCAL_SUPPORTED
1826 /* Write the pCAL chunk (described in the PNG extensions document) */
1827 void /* PRIVATE */
1828 png_write_pCAL(png_structrp png_ptr, png_charp purpose, png_int_32 X0,
1829 png_int_32 X1, int type, int nparams, png_const_charp units,
1830 png_charpp params)
1831 {
1832 png_uint_32 purpose_len;
1833 png_size_t units_len, total_len;
1834 png_size_tp params_len;
1835 png_byte buf[10];
1836 png_byte new_purpose[80];
1837 int i;
1838
1839 png_debug1(1, "in png_write_pCAL (%d parameters)", nparams);
1840
1841 if (type >= PNG_EQUATION_LAST)
1842 png_error(png_ptr, "Unrecognized equation type for pCAL chunk");
1843
1844 purpose_len = png_check_keyword(png_ptr, purpose, new_purpose);
1845
1846 if (purpose_len == 0)
1847 png_error(png_ptr, "pCAL: invalid keyword");
1848
1849 ++purpose_len; /* terminator */
1850
1851 png_debug1(3, "pCAL purpose length = %d", (int)purpose_len);
1852 units_len = strlen(units) + (nparams == 0 ? 0 : 1);
1853 png_debug1(3, "pCAL units length = %d", (int)units_len);
1854 total_len = purpose_len + units_len + 10;
1855
1856 params_len = (png_size_tp)png_malloc(png_ptr,
1857 (png_alloc_size_t)(nparams * (sizeof (png_size_t))));
1858
1859 /* Find the length of each parameter, making sure we don't count the
1860 * null terminator for the last parameter.
1861 */
1862 for (i = 0; i < nparams; i++)
1863 {
1864 params_len[i] = strlen(params[i]) + (i == nparams - 1 ? 0 : 1);
1865 png_debug2(3, "pCAL parameter %d length = %lu", i,
1866 (unsigned long)params_len[i]);
1867 total_len += params_len[i];
1868 }
1869
1870 png_debug1(3, "pCAL total length = %d", (int)total_len);
1871 png_write_chunk_header(png_ptr, png_pCAL, (png_uint_32)total_len);
1872 png_write_chunk_data(png_ptr, new_purpose, purpose_len);
1873 png_save_int_32(buf, X0);
1874 png_save_int_32(buf + 4, X1);
1875 buf[8] = (png_byte)type;
1876 buf[9] = (png_byte)nparams;
1877 png_write_chunk_data(png_ptr, buf, (png_size_t)10);
1878 png_write_chunk_data(png_ptr, (png_const_bytep)units, (png_size_t)units_len);
1879
1880 for (i = 0; i < nparams; i++)
1881 {
1882 png_write_chunk_data(png_ptr, (png_const_bytep)params[i], params_len[i]);
1883 }
1884
1885 png_free(png_ptr, params_len);
1886 png_write_chunk_end(png_ptr);
1887 }
1888 #endif
1889
1890 #ifdef PNG_WRITE_sCAL_SUPPORTED
1891 /* Write the sCAL chunk */
1892 void /* PRIVATE */
1893 png_write_sCAL_s(png_structrp png_ptr, int unit, png_const_charp width,
1894 png_const_charp height)
1895 {
1896 png_byte buf[64];
1897 png_size_t wlen, hlen, total_len;
1898
1899 png_debug(1, "in png_write_sCAL_s");
1900
1901 wlen = strlen(width);
1902 hlen = strlen(height);
1903 total_len = wlen + hlen + 2;
1904
1905 if (total_len > 64)
1906 {
1907 png_warning(png_ptr, "Can't write sCAL (buffer too small)");
1908 return;
1909 }
1910
1911 buf[0] = (png_byte)unit;
1912 memcpy(buf + 1, width, wlen + 1); /* Append the '\0' here */
1913 memcpy(buf + wlen + 2, height, hlen); /* Do NOT append the '\0' here */
1914
1915 png_debug1(3, "sCAL total length = %u", (unsigned int)total_len);
1916 png_write_complete_chunk(png_ptr, png_sCAL, buf, total_len);
1917 }
1918 #endif
1919
1920 #ifdef PNG_WRITE_pHYs_SUPPORTED
1921 /* Write the pHYs chunk */
1922 void /* PRIVATE */
1923 png_write_pHYs(png_structrp png_ptr, png_uint_32 x_pixels_per_unit,
1924 png_uint_32 y_pixels_per_unit,
1925 int unit_type)
1926 {
1927 png_byte buf[9];
1928
1929 png_debug(1, "in png_write_pHYs");
1930
1931 if (unit_type >= PNG_RESOLUTION_LAST)
1932 png_warning(png_ptr, "Unrecognized unit type for pHYs chunk");
1933
1934 png_save_uint_32(buf, x_pixels_per_unit);
1935 png_save_uint_32(buf + 4, y_pixels_per_unit);
1936 buf[8] = (png_byte)unit_type;
1937
1938 png_write_complete_chunk(png_ptr, png_pHYs, buf, (png_size_t)9);
1939 }
1940 #endif
1941
1942 #ifdef PNG_WRITE_tIME_SUPPORTED
1943 /* Write the tIME chunk. Use either png_convert_from_struct_tm()
1944 * or png_convert_from_time_t(), or fill in the structure yourself.
1945 */
1946 void /* PRIVATE */
1947 png_write_tIME(png_structrp png_ptr, png_const_timep mod_time)
1948 {
1949 png_byte buf[7];
1950
1951 png_debug(1, "in png_write_tIME");
1952
1953 if (mod_time->month > 12 || mod_time->month < 1 ||
1954 mod_time->day > 31 || mod_time->day < 1 ||
1955 mod_time->hour > 23 || mod_time->second > 60)
1956 {
1957 png_warning(png_ptr, "Invalid time specified for tIME chunk");
1958 return;
1959 }
1960
1961 png_save_uint_16(buf, mod_time->year);
1962 buf[2] = mod_time->month;
1963 buf[3] = mod_time->day;
1964 buf[4] = mod_time->hour;
1965 buf[5] = mod_time->minute;
1966 buf[6] = mod_time->second;
1967
1968 png_write_complete_chunk(png_ptr, png_tIME, buf, (png_size_t)7);
1969 }
1970 #endif
1971
1972 /* Initializes the row writing capability of libpng */
1973 void /* PRIVATE */
1974 png_write_start_row(png_structrp png_ptr)
1975 {
1976 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1977 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
1978
1979 /* Start of interlace block */
1980 static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
1981
1982 /* Offset to next interlace block */
1983 static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
1984
1985 /* Start of interlace block in the y direction */
1986 static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
1987
1988 /* Offset to next interlace block in the y direction */
1989 static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
1990 #endif
1991
1992 png_alloc_size_t buf_size;
1993 int usr_pixel_depth;
1994
1995 #ifdef PNG_WRITE_FILTER_SUPPORTED
1996 png_byte filters;
1997 #endif
1998
1999 png_debug(1, "in png_write_start_row");
2000
2001 usr_pixel_depth = png_ptr->usr_channels * png_ptr->usr_bit_depth;
2002 buf_size = PNG_ROWBYTES(usr_pixel_depth, png_ptr->width) + 1;
2003
2004 /* 1.5.6: added to allow checking in the row write code. */
2005 png_ptr->transformed_pixel_depth = png_ptr->pixel_depth;
2006 png_ptr->maximum_pixel_depth = (png_byte)usr_pixel_depth;
2007
2008 /* Set up row buffer */
2009 png_ptr->row_buf = png_voidcast(png_bytep, png_malloc(png_ptr, buf_size));
2010
2011 png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE;
2012
2013 #ifdef PNG_WRITE_FILTER_SUPPORTED
2014 filters = png_ptr->do_filter;
2015
2016 if (png_ptr->height == 1)
2017 filters &= 0xff & ~(PNG_FILTER_UP|PNG_FILTER_AVG|PNG_FILTER_PAETH);
2018
2019 if (png_ptr->width == 1)
2020 filters &= 0xff & ~(PNG_FILTER_SUB|PNG_FILTER_AVG|PNG_FILTER_PAETH);
2021
2022 if (filters == 0)
2023 filters = PNG_FILTER_NONE;
2024
2025 png_ptr->do_filter = filters;
2026
2027 if (((filters & (PNG_FILTER_SUB | PNG_FILTER_UP | PNG_FILTER_AVG |
2028 PNG_FILTER_PAETH)) != 0) && png_ptr->try_row == NULL)
2029 {
2030 int num_filters = 0;
2031
2032 png_ptr->try_row = png_voidcast(png_bytep, png_malloc(png_ptr, buf_size));
2033
2034 if (filters & PNG_FILTER_SUB)
2035 num_filters++;
2036
2037 if (filters & PNG_FILTER_UP)
2038 num_filters++;
2039
2040 if (filters & PNG_FILTER_AVG)
2041 num_filters++;
2042
2043 if (filters & PNG_FILTER_PAETH)
2044 num_filters++;
2045
2046 if (num_filters > 1)
2047 png_ptr->tst_row = png_voidcast(png_bytep, png_malloc(png_ptr,
2048 buf_size));
2049 }
2050
2051 /* We only need to keep the previous row if we are using one of the following
2052 * filters.
2053 */
2054 if ((filters & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH)) != 0)
2055 png_ptr->prev_row = png_voidcast(png_bytep,
2056 png_calloc(png_ptr, buf_size));
2057 #endif /* WRITE_FILTER */
2058
2059 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
2060 /* If interlaced, we need to set up width and height of pass */
2061 if (png_ptr->interlaced != 0)
2062 {
2063 if ((png_ptr->transformations & PNG_INTERLACE) == 0)
2064 {
2065 png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
2066 png_pass_ystart[0]) / png_pass_yinc[0];
2067
2068 png_ptr->usr_width = (png_ptr->width + png_pass_inc[0] - 1 -
2069 png_pass_start[0]) / png_pass_inc[0];
2070 }
2071
2072 else
2073 {
2074 png_ptr->num_rows = png_ptr->height;
2075 png_ptr->usr_width = png_ptr->width;
2076 }
2077 }
2078
2079 else
2080 #endif
2081 {
2082 png_ptr->num_rows = png_ptr->height;
2083 png_ptr->usr_width = png_ptr->width;
2084 }
2085 }
2086
2087 /* Internal use only. Called when finished processing a row of data. */
2088 void /* PRIVATE */
2089 png_write_finish_row(png_structrp png_ptr)
2090 {
2091 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
2092 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
2093
2094 /* Start of interlace block */
2095 static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
2096
2097 /* Offset to next interlace block */
2098 static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
2099
2100 /* Start of interlace block in the y direction */
2101 static PNG_CONST png_byte png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
2102
2103 /* Offset to next interlace block in the y direction */
2104 static PNG_CONST png_byte png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
2105 #endif
2106
2107 png_debug(1, "in png_write_finish_row");
2108
2109 /* Next row */
2110 png_ptr->row_number++;
2111
2112 /* See if we are done */
2113 if (png_ptr->row_number < png_ptr->num_rows)
2114 return;
2115
2116 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
2117 /* If interlaced, go to next pass */
2118 if (png_ptr->interlaced != 0)
2119 {
2120 png_ptr->row_number = 0;
2121 if ((png_ptr->transformations & PNG_INTERLACE) != 0)
2122 {
2123 png_ptr->pass++;
2124 }
2125
2126 else
2127 {
2128 /* Loop until we find a non-zero width or height pass */
2129 do
2130 {
2131 png_ptr->pass++;
2132
2133 if (png_ptr->pass >= 7)
2134 break;
2135
2136 png_ptr->usr_width = (png_ptr->width +
2137 png_pass_inc[png_ptr->pass] - 1 -
2138 png_pass_start[png_ptr->pass]) /
2139 png_pass_inc[png_ptr->pass];
2140
2141 png_ptr->num_rows = (png_ptr->height +
2142 png_pass_yinc[png_ptr->pass] - 1 -
2143 png_pass_ystart[png_ptr->pass]) /
2144 png_pass_yinc[png_ptr->pass];
2145
2146 if ((png_ptr->transformations & PNG_INTERLACE) != 0)
2147 break;
2148
2149 } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0);
2150
2151 }
2152
2153 /* Reset the row above the image for the next pass */
2154 if (png_ptr->pass < 7)
2155 {
2156 if (png_ptr->prev_row != NULL)
2157 memset(png_ptr->prev_row, 0,
2158 (png_size_t)(PNG_ROWBYTES(png_ptr->usr_channels*
2159 png_ptr->usr_bit_depth, png_ptr->width)) + 1);
2160
2161 return;
2162 }
2163 }
2164 #endif
2165
2166 /* If we get here, we've just written the last row, so we need
2167 to flush the compressor */
2168 png_compress_IDAT(png_ptr, NULL, 0, Z_FINISH);
2169 }
2170
2171 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
2172 /* Pick out the correct pixels for the interlace pass.
2173 * The basic idea here is to go through the row with a source
2174 * pointer and a destination pointer (sp and dp), and copy the
2175 * correct pixels for the pass. As the row gets compacted,
2176 * sp will always be >= dp, so we should never overwrite anything.
2177 * See the default: case for the easiest code to understand.
2178 */
2179 void /* PRIVATE */
2180 png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
2181 {
2182 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
2183
2184 /* Start of interlace block */
2185 static PNG_CONST png_byte png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
2186
2187 /* Offset to next interlace block */
2188 static PNG_CONST png_byte png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
2189
2190 png_debug(1, "in png_do_write_interlace");
2191
2192 /* We don't have to do anything on the last pass (6) */
2193 if (pass < 6)
2194 {
2195 /* Each pixel depth is handled separately */
2196 switch (row_info->pixel_depth)
2197 {
2198 case 1:
2199 {
2200 png_bytep sp;
2201 png_bytep dp;
2202 unsigned int shift;
2203 int d;
2204 int value;
2205 png_uint_32 i;
2206 png_uint_32 row_width = row_info->width;
2207
2208 dp = row;
2209 d = 0;
2210 shift = 7;
2211
2212 for (i = png_pass_start[pass]; i < row_width;
2213 i += png_pass_inc[pass])
2214 {
2215 sp = row + (png_size_t)(i >> 3);
2216 value = (int)(*sp >> (7 - (int)(i & 0x07))) & 0x01;
2217 d |= (value << shift);
2218
2219 if (shift == 0)
2220 {
2221 shift = 7;
2222 *dp++ = (png_byte)d;
2223 d = 0;
2224 }
2225
2226 else
2227 shift--;
2228
2229 }
2230 if (shift != 7)
2231 *dp = (png_byte)d;
2232
2233 break;
2234 }
2235
2236 case 2:
2237 {
2238 png_bytep sp;
2239 png_bytep dp;
2240 unsigned int shift;
2241 int d;
2242 int value;
2243 png_uint_32 i;
2244 png_uint_32 row_width = row_info->width;
2245
2246 dp = row;
2247 shift = 6;
2248 d = 0;
2249
2250 for (i = png_pass_start[pass]; i < row_width;
2251 i += png_pass_inc[pass])
2252 {
2253 sp = row + (png_size_t)(i >> 2);
2254 value = (*sp >> ((3 - (int)(i & 0x03)) << 1)) & 0x03;
2255 d |= (value << shift);
2256
2257 if (shift == 0)
2258 {
2259 shift = 6;
2260 *dp++ = (png_byte)d;
2261 d = 0;
2262 }
2263
2264 else
2265 shift -= 2;
2266 }
2267 if (shift != 6)
2268 *dp = (png_byte)d;
2269
2270 break;
2271 }
2272
2273 case 4:
2274 {
2275 png_bytep sp;
2276 png_bytep dp;
2277 unsigned int shift;
2278 int d;
2279 int value;
2280 png_uint_32 i;
2281 png_uint_32 row_width = row_info->width;
2282
2283 dp = row;
2284 shift = 4;
2285 d = 0;
2286 for (i = png_pass_start[pass]; i < row_width;
2287 i += png_pass_inc[pass])
2288 {
2289 sp = row + (png_size_t)(i >> 1);
2290 value = (*sp >> ((1 - (int)(i & 0x01)) << 2)) & 0x0f;
2291 d |= (value << shift);
2292
2293 if (shift == 0)
2294 {
2295 shift = 4;
2296 *dp++ = (png_byte)d;
2297 d = 0;
2298 }
2299
2300 else
2301 shift -= 4;
2302 }
2303 if (shift != 4)
2304 *dp = (png_byte)d;
2305
2306 break;
2307 }
2308
2309 default:
2310 {
2311 png_bytep sp;
2312 png_bytep dp;
2313 png_uint_32 i;
2314 png_uint_32 row_width = row_info->width;
2315 png_size_t pixel_bytes;
2316
2317 /* Start at the beginning */
2318 dp = row;
2319
2320 /* Find out how many bytes each pixel takes up */
2321 pixel_bytes = (row_info->pixel_depth >> 3);
2322
2323 /* Loop through the row, only looking at the pixels that matter */
2324 for (i = png_pass_start[pass]; i < row_width;
2325 i += png_pass_inc[pass])
2326 {
2327 /* Find out where the original pixel is */
2328 sp = row + (png_size_t)i * pixel_bytes;
2329
2330 /* Move the pixel */
2331 if (dp != sp)
2332 memcpy(dp, sp, pixel_bytes);
2333
2334 /* Next pixel */
2335 dp += pixel_bytes;
2336 }
2337 break;
2338 }
2339 }
2340 /* Set new row width */
2341 row_info->width = (row_info->width +
2342 png_pass_inc[pass] - 1 -
2343 png_pass_start[pass]) /
2344 png_pass_inc[pass];
2345
2346 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
2347 row_info->width);
2348 }
2349 }
2350 #endif
2351
2352
2353 /* This filters the row, chooses which filter to use, if it has not already
2354 * been specified by the application, and then writes the row out with the
2355 * chosen filter.
2356 */
2357 static void /* PRIVATE */
2358 png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,
2359 png_size_t row_bytes);
2360
2361 #ifdef PNG_WRITE_FILTER_SUPPORTED
2362 static png_size_t /* PRIVATE */
2363 png_setup_sub_row(png_structrp png_ptr, const png_uint_32 bpp,
2364 const png_size_t row_bytes, const png_size_t lmins)
2365 {
2366 png_bytep rp, dp, lp;
2367 png_size_t i;
2368 png_size_t sum = 0;
2369 int v;
2370
2371 png_ptr->try_row[0] = PNG_FILTER_VALUE_SUB;
2372
2373 for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1; i < bpp;
2374 i++, rp++, dp++)
2375 {
2376 v = *dp = *rp;
2377 sum += (v < 128) ? v : 256 - v;
2378 }
2379
2380 for (lp = png_ptr->row_buf + 1; i < row_bytes;
2381 i++, rp++, lp++, dp++)
2382 {
2383 v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
2384 sum += (v < 128) ? v : 256 - v;
2385
2386 if (sum > lmins) /* We are already worse, don't continue. */
2387 break;
2388 }
2389
2390 return (sum);
2391 }
2392
2393 static png_size_t /* PRIVATE */
2394 png_setup_up_row(png_structrp png_ptr, const png_size_t row_bytes,
2395 const png_size_t lmins)
2396 {
2397 png_bytep rp, dp, pp;
2398 png_size_t i;
2399 png_size_t sum = 0;
2400 int v;
2401
2402 png_ptr->try_row[0] = PNG_FILTER_VALUE_UP;
2403
2404 for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
2405 pp = png_ptr->prev_row + 1; i < row_bytes;
2406 i++, rp++, pp++, dp++)
2407 {
2408 v = *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
2409 sum += (v < 128) ? v : 256 - v;
2410
2411 if (sum > lmins) /* We are already worse, don't continue. */
2412 break;
2413 }
2414
2415 return (sum);
2416 }
2417
2418 static png_size_t /* PRIVATE */
2419 png_setup_avg_row(png_structrp png_ptr, const png_uint_32 bpp,
2420 const png_size_t row_bytes, const png_size_t lmins)
2421 {
2422 png_bytep rp, dp, pp, lp;
2423 png_uint_32 i;
2424 png_size_t sum = 0;
2425 int v;
2426
2427 png_ptr->try_row[0] = PNG_FILTER_VALUE_AVG;
2428
2429 for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
2430 pp = png_ptr->prev_row + 1; i < bpp; i++)
2431 {
2432 v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
2433
2434 sum += (v < 128) ? v : 256 - v;
2435 }
2436
2437 for (lp = png_ptr->row_buf + 1; i < row_bytes; i++)
2438 {
2439 v = *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
2440 & 0xff);
2441
2442 sum += (v < 128) ? v : 256 - v;
2443
2444 if (sum > lmins) /* We are already worse, don't continue. */
2445 break;
2446 }
2447
2448 return (sum);
2449 }
2450
2451 static png_size_t /* PRIVATE */
2452 png_setup_paeth_row(png_structrp png_ptr, const png_uint_32 bpp,
2453 const png_size_t row_bytes, const png_size_t lmins)
2454 {
2455 png_bytep rp, dp, pp, cp, lp;
2456 png_size_t i;
2457 png_size_t sum = 0;
2458 int v;
2459
2460 png_ptr->try_row[0] = PNG_FILTER_VALUE_PAETH;
2461
2462 for (i = 0, rp = png_ptr->row_buf + 1, dp = png_ptr->try_row + 1,
2463 pp = png_ptr->prev_row + 1; i < bpp; i++)
2464 {
2465 v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
2466
2467 sum += (v < 128) ? v : 256 - v;
2468 }
2469
2470 for (lp = png_ptr->row_buf + 1, cp = png_ptr->prev_row + 1; i < row_bytes;
2471 i++)
2472 {
2473 int a, b, c, pa, pb, pc, p;
2474
2475 b = *pp++;
2476 c = *cp++;
2477 a = *lp++;
2478
2479 p = b - c;
2480 pc = a - c;
2481
2482 #ifdef PNG_USE_ABS
2483 pa = abs(p);
2484 pb = abs(pc);
2485 pc = abs(p + pc);
2486 #else
2487 pa = p < 0 ? -p : p;
2488 pb = pc < 0 ? -pc : pc;
2489 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
2490 #endif
2491
2492 p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
2493
2494 v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
2495
2496 sum += (v < 128) ? v : 256 - v;
2497
2498 if (sum > lmins) /* We are already worse, don't continue. */
2499 break;
2500 }
2501
2502 return (sum);
2503 }
2504 #endif /* WRITE_FILTER */
2505
2506 void /* PRIVATE */
2507 png_write_find_filter(png_structrp png_ptr, png_row_infop row_info)
2508 {
2509 #ifndef PNG_WRITE_FILTER_SUPPORTED
2510 png_write_filtered_row(png_ptr, png_ptr->row_buf, row_info->rowbytes+1);
2511 #else
2512 png_byte filter_to_do = png_ptr->do_filter;
2513 png_bytep row_buf;
2514 png_bytep best_row;
2515 png_uint_32 bpp;
2516 png_size_t mins;
2517 png_size_t row_bytes = row_info->rowbytes;
2518
2519 png_debug(1, "in png_write_find_filter");
2520
2521 /* Find out how many bytes offset each pixel is */
2522 bpp = (row_info->pixel_depth + 7) >> 3;
2523
2524 row_buf = png_ptr->row_buf;
2525 mins = PNG_SIZE_MAX - 256/* so we can detect potential overflow of the
2526 running sum */;
2527
2528 /* The prediction method we use is to find which method provides the
2529 * smallest value when summing the absolute values of the distances
2530 * from zero, using anything >= 128 as negative numbers. This is known
2531 * as the "minimum sum of absolute differences" heuristic. Other
2532 * heuristics are the "weighted minimum sum of absolute differences"
2533 * (experimental and can in theory improve compression), and the "zlib
2534 * predictive" method (not implemented yet), which does test compressions
2535 * of lines using different filter methods, and then chooses the
2536 * (series of) filter(s) that give minimum compressed data size (VERY
2537 * computationally expensive).
2538 *
2539 * GRR 980525: consider also
2540 *
2541 * (1) minimum sum of absolute differences from running average (i.e.,
2542 * keep running sum of non-absolute differences & count of bytes)
2543 * [track dispersion, too? restart average if dispersion too large?]
2544 *
2545 * (1b) minimum sum of absolute differences from sliding average, probably
2546 * with window size <= deflate window (usually 32K)
2547 *
2548 * (2) minimum sum of squared differences from zero or running average
2549 * (i.e., ~ root-mean-square approach)
2550 */
2551
2552
2553 /* We don't need to test the 'no filter' case if this is the only filter
2554 * that has been chosen, as it doesn't actually do anything to the data.
2555 */
2556 best_row = png_ptr->row_buf;
2557
2558
2559 if ((filter_to_do & PNG_FILTER_NONE) != 0 && filter_to_do != PNG_FILTER_NONE)
2560 {
2561 png_bytep rp;
2562 png_size_t sum = 0;
2563 png_size_t i;
2564 int v;
2565
2566 if (PNG_SIZE_MAX/128 <= row_bytes)
2567 {
2568 for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
2569 {
2570 /* Check for overflow */
2571 if (sum > PNG_SIZE_MAX/128 - 256)
2572 break;
2573
2574 v = *rp;
2575 sum += (v < 128) ? v : 256 - v;
2576 }
2577 }
2578 else /* Overflow is not possible */
2579 {
2580 for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
2581 {
2582 v = *rp;
2583 sum += (v < 128) ? v : 256 - v;
2584 }
2585 }
2586
2587 mins = sum;
2588 }
2589
2590 /* Sub filter */
2591 if (filter_to_do == PNG_FILTER_SUB)
2592 /* It's the only filter so no testing is needed */
2593 {
2594 (void) png_setup_sub_row(png_ptr, bpp, row_bytes, mins);
2595 best_row = png_ptr->try_row;
2596 }
2597
2598 else if ((filter_to_do & PNG_FILTER_SUB) != 0)
2599 {
2600 png_size_t sum;
2601 png_size_t lmins = mins;
2602
2603 sum = png_setup_sub_row(png_ptr, bpp, row_bytes, lmins);
2604
2605 if (sum < mins)
2606 {
2607 mins = sum;
2608 best_row = png_ptr->try_row;
2609 if (png_ptr->tst_row != NULL)
2610 {
2611 png_ptr->try_row = png_ptr->tst_row;
2612 png_ptr->tst_row = best_row;
2613 }
2614 }
2615 }
2616
2617 /* Up filter */
2618 if (filter_to_do == PNG_FILTER_UP)
2619 {
2620 (void) png_setup_up_row(png_ptr, row_bytes, mins);
2621 best_row = png_ptr->try_row;
2622 }
2623
2624 else if ((filter_to_do & PNG_FILTER_UP) != 0)
2625 {
2626 png_size_t sum;
2627 png_size_t lmins = mins;
2628
2629 sum = png_setup_up_row(png_ptr, row_bytes, lmins);
2630
2631 if (sum < mins)
2632 {
2633 mins = sum;
2634 best_row = png_ptr->try_row;
2635 if (png_ptr->tst_row != NULL)
2636 {
2637 png_ptr->try_row = png_ptr->tst_row;
2638 png_ptr->tst_row = best_row;
2639 }
2640 }
2641 }
2642
2643 /* Avg filter */
2644 if (filter_to_do == PNG_FILTER_AVG)
2645 {
2646 (void) png_setup_avg_row(png_ptr, bpp, row_bytes, mins);
2647 best_row = png_ptr->try_row;
2648 }
2649
2650 else if ((filter_to_do & PNG_FILTER_AVG) != 0)
2651 {
2652 png_size_t sum;
2653 png_size_t lmins = mins;
2654
2655 sum= png_setup_avg_row(png_ptr, bpp, row_bytes, lmins);
2656
2657 if (sum < mins)
2658 {
2659 mins = sum;
2660 best_row = png_ptr->try_row;
2661 if (png_ptr->tst_row != NULL)
2662 {
2663 png_ptr->try_row = png_ptr->tst_row;
2664 png_ptr->tst_row = best_row;
2665 }
2666 }
2667 }
2668
2669 /* Paeth filter */
2670 if ((filter_to_do == PNG_FILTER_PAETH) != 0)
2671 {
2672 (void) png_setup_paeth_row(png_ptr, bpp, row_bytes, mins);
2673 best_row = png_ptr->try_row;
2674 }
2675
2676 else if ((filter_to_do & PNG_FILTER_PAETH) != 0)
2677 {
2678 png_size_t sum;
2679 png_size_t lmins = mins;
2680
2681 sum = png_setup_paeth_row(png_ptr, bpp, row_bytes, lmins);
2682
2683 if (sum < mins)
2684 {
2685 best_row = png_ptr->try_row;
2686 if (png_ptr->tst_row != NULL)
2687 {
2688 png_ptr->try_row = png_ptr->tst_row;
2689 png_ptr->tst_row = best_row;
2690 }
2691 }
2692 }
2693
2694 /* Do the actual writing of the filtered row data from the chosen filter. */
2695 png_write_filtered_row(png_ptr, best_row, row_info->rowbytes+1);
2696
2697 #endif /* WRITE_FILTER */
2698 }
2699
2700
2701 /* Do the actual writing of a previously filtered row. */
2702 static void
2703 png_write_filtered_row(png_structrp png_ptr, png_bytep filtered_row,
2704 png_size_t full_row_length/*includes filter byte*/)
2705 {
2706 png_debug(1, "in png_write_filtered_row");
2707
2708 png_debug1(2, "filter = %d", filtered_row[0]);
2709
2710 png_compress_IDAT(png_ptr, filtered_row, full_row_length, Z_NO_FLUSH);
2711
2712 #ifdef PNG_WRITE_FILTER_SUPPORTED
2713 /* Swap the current and previous rows */
2714 if (png_ptr->prev_row != NULL)
2715 {
2716 png_bytep tptr;
2717
2718 tptr = png_ptr->prev_row;
2719 png_ptr->prev_row = png_ptr->row_buf;
2720 png_ptr->row_buf = tptr;
2721 }
2722 #endif /* WRITE_FILTER */
2723
2724 /* Finish row - updates counters and flushes zlib if last row */
2725 png_write_finish_row(png_ptr);
2726
2727 #ifdef PNG_WRITE_FLUSH_SUPPORTED
2728 png_ptr->flush_rows++;
2729
2730 if (png_ptr->flush_dist > 0 &&
2731 png_ptr->flush_rows >= png_ptr->flush_dist)
2732 {
2733 png_write_flush(png_ptr);
2734 }
2735 #endif /* WRITE_FLUSH */
2736 }
2737 #endif /* WRITE */