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source: vbox/trunk/src/libs/libpng-1.2.54/pngwutil.c@ 76549

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libpng 1.2.54 unmodified

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1
2/* pngwutil.c - utilities to write a PNG file
3 *
4 * Last changed in libpng 1.2.54 [November 12, 2015]
5 * Copyright (c) 1998-2015 Glenn Randers-Pehrson
6 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
7 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
8 *
9 * This code is released under the libpng license.
10 * For conditions of distribution and use, see the disclaimer
11 * and license in png.h
12 */
13
14#define PNG_INTERNAL
15#define PNG_NO_PEDANTIC_WARNINGS
16#include "png.h"
17#ifdef PNG_WRITE_SUPPORTED
18
19/* Place a 32-bit number into a buffer in PNG byte order. We work
20 * with unsigned numbers for convenience, although one supported
21 * ancillary chunk uses signed (two's complement) numbers.
22 */
23void PNGAPI
24png_save_uint_32(png_bytep buf, png_uint_32 i)
25{
26 buf[0] = (png_byte)((i >> 24) & 0xff);
27 buf[1] = (png_byte)((i >> 16) & 0xff);
28 buf[2] = (png_byte)((i >> 8) & 0xff);
29 buf[3] = (png_byte)(i & 0xff);
30}
31
32/* The png_save_int_32 function assumes integers are stored in two's
33 * complement format. If this isn't the case, then this routine needs to
34 * be modified to write data in two's complement format.
35 */
36void PNGAPI
37png_save_int_32(png_bytep buf, png_int_32 i)
38{
39 buf[0] = (png_byte)((i >> 24) & 0xff);
40 buf[1] = (png_byte)((i >> 16) & 0xff);
41 buf[2] = (png_byte)((i >> 8) & 0xff);
42 buf[3] = (png_byte)(i & 0xff);
43}
44
45/* Place a 16-bit number into a buffer in PNG byte order.
46 * The parameter is declared unsigned int, not png_uint_16,
47 * just to avoid potential problems on pre-ANSI C compilers.
48 */
49void PNGAPI
50png_save_uint_16(png_bytep buf, unsigned int i)
51{
52 buf[0] = (png_byte)((i >> 8) & 0xff);
53 buf[1] = (png_byte)(i & 0xff);
54}
55
56/* Simple function to write the signature. If we have already written
57 * the magic bytes of the signature, or more likely, the PNG stream is
58 * being embedded into another stream and doesn't need its own signature,
59 * we should call png_set_sig_bytes() to tell libpng how many of the
60 * bytes have already been written.
61 */
62void /* PRIVATE */
63png_write_sig(png_structp png_ptr)
64{
65 png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
66
67 /* Write the rest of the 8 byte signature */
68 png_write_data(png_ptr, &png_signature[png_ptr->sig_bytes],
69 (png_size_t)(8 - png_ptr->sig_bytes));
70 if (png_ptr->sig_bytes < 3)
71 png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
72}
73
74/* Write a PNG chunk all at once. The type is an array of ASCII characters
75 * representing the chunk name. The array must be at least 4 bytes in
76 * length, and does not need to be null terminated. To be safe, pass the
77 * pre-defined chunk names here, and if you need a new one, define it
78 * where the others are defined. The length is the length of the data.
79 * All the data must be present. If that is not possible, use the
80 * png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end()
81 * functions instead.
82 */
83void PNGAPI
84png_write_chunk(png_structp png_ptr, png_bytep chunk_name,
85 png_bytep data, png_size_t length)
86{
87 if (png_ptr == NULL)
88 return;
89 png_write_chunk_start(png_ptr, chunk_name, (png_uint_32)length);
90 png_write_chunk_data(png_ptr, data, (png_size_t)length);
91 png_write_chunk_end(png_ptr);
92}
93
94/* Write the start of a PNG chunk. The type is the chunk type.
95 * The total_length is the sum of the lengths of all the data you will be
96 * passing in png_write_chunk_data().
97 */
98void PNGAPI
99png_write_chunk_start(png_structp png_ptr, png_bytep chunk_name,
100 png_uint_32 length)
101{
102 png_byte buf[8];
103
104 png_debug2(0, "Writing %s chunk, length = %lu", chunk_name,
105 (unsigned long)length);
106
107 if (png_ptr == NULL)
108 return;
109
110
111 /* Write the length and the chunk name */
112 png_save_uint_32(buf, length);
113 png_memcpy(buf + 4, chunk_name, 4);
114 png_write_data(png_ptr, buf, (png_size_t)8);
115 /* Put the chunk name into png_ptr->chunk_name */
116 png_memcpy(png_ptr->chunk_name, chunk_name, 4);
117 /* Reset the crc and run it over the chunk name */
118 png_reset_crc(png_ptr);
119 png_calculate_crc(png_ptr, chunk_name, (png_size_t)4);
120}
121
122/* Write the data of a PNG chunk started with png_write_chunk_start().
123 * Note that multiple calls to this function are allowed, and that the
124 * sum of the lengths from these calls *must* add up to the total_length
125 * given to png_write_chunk_start().
126 */
127void PNGAPI
128png_write_chunk_data(png_structp png_ptr, png_bytep data, png_size_t length)
129{
130 /* Write the data, and run the CRC over it */
131 if (png_ptr == NULL)
132 return;
133 if (data != NULL && length > 0)
134 {
135 png_write_data(png_ptr, data, length);
136 /* Update the CRC after writing the data,
137 * in case that the user I/O routine alters it.
138 */
139 png_calculate_crc(png_ptr, data, length);
140 }
141}
142
143/* Finish a chunk started with png_write_chunk_start(). */
144void PNGAPI
145png_write_chunk_end(png_structp png_ptr)
146{
147 png_byte buf[4];
148
149 if (png_ptr == NULL) return;
150
151 /* Write the crc in a single operation */
152 png_save_uint_32(buf, png_ptr->crc);
153
154 png_write_data(png_ptr, buf, (png_size_t)4);
155}
156
157#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_iCCP_SUPPORTED)
158/* This pair of functions encapsulates the operation of (a) compressing a
159 * text string, and (b) issuing it later as a series of chunk data writes.
160 * The compression_state structure is shared context for these functions
161 * set up by the caller in order to make the whole mess thread-safe.
162 */
163
164typedef struct
165{
166 char *input; /* The uncompressed input data */
167 int input_len; /* Its length */
168 int num_output_ptr; /* Number of output pointers used */
169 int max_output_ptr; /* Size of output_ptr */
170 png_charpp output_ptr; /* Array of pointers to output */
171} compression_state;
172
173/* Compress given text into storage in the png_ptr structure */
174static int /* PRIVATE */
175png_text_compress(png_structp png_ptr,
176 png_charp text, png_size_t text_len, int compression,
177 compression_state *comp)
178{
179 int ret;
180
181 comp->num_output_ptr = 0;
182 comp->max_output_ptr = 0;
183 comp->output_ptr = NULL;
184 comp->input = NULL;
185 comp->input_len = 0;
186
187 /* We may just want to pass the text right through */
188 if (compression == PNG_TEXT_COMPRESSION_NONE)
189 {
190 comp->input = text;
191 comp->input_len = text_len;
192 return((int)text_len);
193 }
194
195 if (compression >= PNG_TEXT_COMPRESSION_LAST)
196 {
197#if defined(PNG_STDIO_SUPPORTED) && !defined(_WIN32_WCE)
198 char msg[50];
199 png_snprintf(msg, 50, "Unknown compression type %d", compression);
200 png_warning(png_ptr, msg);
201#else
202 png_warning(png_ptr, "Unknown compression type");
203#endif
204 }
205
206 /* We can't write the chunk until we find out how much data we have,
207 * which means we need to run the compressor first and save the
208 * output. This shouldn't be a problem, as the vast majority of
209 * comments should be reasonable, but we will set up an array of
210 * malloc'd pointers to be sure.
211 *
212 * If we knew the application was well behaved, we could simplify this
213 * greatly by assuming we can always malloc an output buffer large
214 * enough to hold the compressed text ((1001 * text_len / 1000) + 12)
215 * and malloc this directly. The only time this would be a bad idea is
216 * if we can't malloc more than 64K and we have 64K of random input
217 * data, or if the input string is incredibly large (although this
218 * wouldn't cause a failure, just a slowdown due to swapping).
219 */
220
221 /* Set up the compression buffers */
222 png_ptr->zstream.avail_in = (uInt)text_len;
223 png_ptr->zstream.next_in = (Bytef *)text;
224 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
225 png_ptr->zstream.next_out = (Bytef *)png_ptr->zbuf;
226
227 /* This is the same compression loop as in png_write_row() */
228 do
229 {
230 /* Compress the data */
231 ret = deflate(&png_ptr->zstream, Z_NO_FLUSH);
232 if (ret != Z_OK)
233 {
234 /* Error */
235 if (png_ptr->zstream.msg != NULL)
236 png_error(png_ptr, png_ptr->zstream.msg);
237 else
238 png_error(png_ptr, "zlib error");
239 }
240 /* Check to see if we need more room */
241 if (!(png_ptr->zstream.avail_out))
242 {
243 /* Make sure the output array has room */
244 if (comp->num_output_ptr >= comp->max_output_ptr)
245 {
246 int old_max;
247
248 old_max = comp->max_output_ptr;
249 comp->max_output_ptr = comp->num_output_ptr + 4;
250 if (comp->output_ptr != NULL)
251 {
252 png_charpp old_ptr;
253
254 old_ptr = comp->output_ptr;
255 comp->output_ptr = (png_charpp)png_malloc(png_ptr,
256 (png_uint_32)
257 (comp->max_output_ptr * png_sizeof(png_charp)));
258 png_memcpy(comp->output_ptr, old_ptr, old_max
259 * png_sizeof(png_charp));
260 png_free(png_ptr, old_ptr);
261 }
262 else
263 comp->output_ptr = (png_charpp)png_malloc(png_ptr,
264 (png_uint_32)
265 (comp->max_output_ptr * png_sizeof(png_charp)));
266 }
267
268 /* Save the data */
269 comp->output_ptr[comp->num_output_ptr] =
270 (png_charp)png_malloc(png_ptr,
271 (png_uint_32)png_ptr->zbuf_size);
272 png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf,
273 png_ptr->zbuf_size);
274 comp->num_output_ptr++;
275
276 /* and reset the buffer */
277 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
278 png_ptr->zstream.next_out = png_ptr->zbuf;
279 }
280 /* Continue until we don't have any more to compress */
281 } while (png_ptr->zstream.avail_in);
282
283 /* Finish the compression */
284 do
285 {
286 /* Tell zlib we are finished */
287 ret = deflate(&png_ptr->zstream, Z_FINISH);
288
289 if (ret == Z_OK)
290 {
291 /* Check to see if we need more room */
292 if (!(png_ptr->zstream.avail_out))
293 {
294 /* Check to make sure our output array has room */
295 if (comp->num_output_ptr >= comp->max_output_ptr)
296 {
297 int old_max;
298
299 old_max = comp->max_output_ptr;
300 comp->max_output_ptr = comp->num_output_ptr + 4;
301 if (comp->output_ptr != NULL)
302 {
303 png_charpp old_ptr;
304
305 old_ptr = comp->output_ptr;
306 /* This could be optimized to realloc() */
307 comp->output_ptr = (png_charpp)png_malloc(png_ptr,
308 (png_uint_32)(comp->max_output_ptr *
309 png_sizeof(png_charp)));
310 png_memcpy(comp->output_ptr, old_ptr,
311 old_max * png_sizeof(png_charp));
312 png_free(png_ptr, old_ptr);
313 }
314 else
315 comp->output_ptr = (png_charpp)png_malloc(png_ptr,
316 (png_uint_32)(comp->max_output_ptr *
317 png_sizeof(png_charp)));
318 }
319
320 /* Save the data */
321 comp->output_ptr[comp->num_output_ptr] =
322 (png_charp)png_malloc(png_ptr,
323 (png_uint_32)png_ptr->zbuf_size);
324 png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf,
325 png_ptr->zbuf_size);
326 comp->num_output_ptr++;
327
328 /* and reset the buffer pointers */
329 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
330 png_ptr->zstream.next_out = png_ptr->zbuf;
331 }
332 }
333 else if (ret != Z_STREAM_END)
334 {
335 /* We got an error */
336 if (png_ptr->zstream.msg != NULL)
337 png_error(png_ptr, png_ptr->zstream.msg);
338 else
339 png_error(png_ptr, "zlib error");
340 }
341 } while (ret != Z_STREAM_END);
342
343 /* Text length is number of buffers plus last buffer */
344 text_len = png_ptr->zbuf_size * comp->num_output_ptr;
345 if (png_ptr->zstream.avail_out < png_ptr->zbuf_size)
346 text_len += png_ptr->zbuf_size - (png_size_t)png_ptr->zstream.avail_out;
347
348 return((int)text_len);
349}
350
351/* Ship the compressed text out via chunk writes */
352static void /* PRIVATE */
353png_write_compressed_data_out(png_structp png_ptr, compression_state *comp)
354{
355 int i;
356
357 /* Handle the no-compression case */
358 if (comp->input)
359 {
360 png_write_chunk_data(png_ptr, (png_bytep)comp->input,
361 (png_size_t)comp->input_len);
362 return;
363 }
364
365 /* Write saved output buffers, if any */
366 for (i = 0; i < comp->num_output_ptr; i++)
367 {
368 png_write_chunk_data(png_ptr, (png_bytep)comp->output_ptr[i],
369 (png_size_t)png_ptr->zbuf_size);
370 png_free(png_ptr, comp->output_ptr[i]);
371 comp->output_ptr[i]=NULL;
372 }
373 if (comp->max_output_ptr != 0)
374 png_free(png_ptr, comp->output_ptr);
375 comp->output_ptr=NULL;
376 /* Write anything left in zbuf */
377 if (png_ptr->zstream.avail_out < (png_uint_32)png_ptr->zbuf_size)
378 png_write_chunk_data(png_ptr, png_ptr->zbuf,
379 (png_size_t)(png_ptr->zbuf_size - png_ptr->zstream.avail_out));
380
381 /* Reset zlib for another zTXt/iTXt or image data */
382 deflateReset(&png_ptr->zstream);
383 png_ptr->zstream.data_type = Z_BINARY;
384}
385#endif
386
387/* Write the IHDR chunk, and update the png_struct with the necessary
388 * information. Note that the rest of this code depends upon this
389 * information being correct.
390 */
391void /* PRIVATE */
392png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height,
393 int bit_depth, int color_type, int compression_type, int filter_type,
394 int interlace_type)
395{
396#ifdef PNG_USE_LOCAL_ARRAYS
397 PNG_IHDR;
398#endif
399 int ret;
400
401 png_byte buf[13]; /* Buffer to store the IHDR info */
402
403 png_debug(1, "in png_write_IHDR");
404
405 /* Check that we have valid input data from the application info */
406 switch (color_type)
407 {
408 case PNG_COLOR_TYPE_GRAY:
409 switch (bit_depth)
410 {
411 case 1:
412 case 2:
413 case 4:
414 case 8:
415 case 16: png_ptr->channels = 1; break;
416 default: png_error(png_ptr,
417 "Invalid bit depth for grayscale image");
418 }
419 break;
420 case PNG_COLOR_TYPE_RGB:
421 if (bit_depth != 8 && bit_depth != 16)
422 png_error(png_ptr, "Invalid bit depth for RGB image");
423 png_ptr->channels = 3;
424 break;
425 case PNG_COLOR_TYPE_PALETTE:
426 switch (bit_depth)
427 {
428 case 1:
429 case 2:
430 case 4:
431 case 8: png_ptr->channels = 1; break;
432 default: png_error(png_ptr, "Invalid bit depth for paletted image");
433 }
434 break;
435 case PNG_COLOR_TYPE_GRAY_ALPHA:
436 if (bit_depth != 8 && bit_depth != 16)
437 png_error(png_ptr, "Invalid bit depth for grayscale+alpha image");
438 png_ptr->channels = 2;
439 break;
440 case PNG_COLOR_TYPE_RGB_ALPHA:
441 if (bit_depth != 8 && bit_depth != 16)
442 png_error(png_ptr, "Invalid bit depth for RGBA image");
443 png_ptr->channels = 4;
444 break;
445 default:
446 png_error(png_ptr, "Invalid image color type specified");
447 }
448
449 if (compression_type != PNG_COMPRESSION_TYPE_BASE)
450 {
451 png_warning(png_ptr, "Invalid compression type specified");
452 compression_type = PNG_COMPRESSION_TYPE_BASE;
453 }
454
455 /* Write filter_method 64 (intrapixel differencing) only if
456 * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
457 * 2. Libpng did not write a PNG signature (this filter_method is only
458 * used in PNG datastreams that are embedded in MNG datastreams) and
459 * 3. The application called png_permit_mng_features with a mask that
460 * included PNG_FLAG_MNG_FILTER_64 and
461 * 4. The filter_method is 64 and
462 * 5. The color_type is RGB or RGBA
463 */
464 if (
465#ifdef PNG_MNG_FEATURES_SUPPORTED
466 !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
467 ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) &&
468 (color_type == PNG_COLOR_TYPE_RGB ||
469 color_type == PNG_COLOR_TYPE_RGB_ALPHA) &&
470 (filter_type == PNG_INTRAPIXEL_DIFFERENCING)) &&
471#endif
472 filter_type != PNG_FILTER_TYPE_BASE)
473 {
474 png_warning(png_ptr, "Invalid filter type specified");
475 filter_type = PNG_FILTER_TYPE_BASE;
476 }
477
478#ifdef PNG_WRITE_INTERLACING_SUPPORTED
479 if (interlace_type != PNG_INTERLACE_NONE &&
480 interlace_type != PNG_INTERLACE_ADAM7)
481 {
482 png_warning(png_ptr, "Invalid interlace type specified");
483 interlace_type = PNG_INTERLACE_ADAM7;
484 }
485#else
486 interlace_type=PNG_INTERLACE_NONE;
487#endif
488
489 /* Save the relevent information */
490 png_ptr->bit_depth = (png_byte)bit_depth;
491 png_ptr->color_type = (png_byte)color_type;
492 png_ptr->interlaced = (png_byte)interlace_type;
493#ifdef PNG_MNG_FEATURES_SUPPORTED
494 png_ptr->filter_type = (png_byte)filter_type;
495#endif
496 png_ptr->compression_type = (png_byte)compression_type;
497 png_ptr->width = width;
498 png_ptr->height = height;
499
500 png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels);
501 png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, width);
502 /* Set the usr info, so any transformations can modify it */
503 png_ptr->usr_width = png_ptr->width;
504 png_ptr->usr_bit_depth = png_ptr->bit_depth;
505 png_ptr->usr_channels = png_ptr->channels;
506
507 /* Pack the header information into the buffer */
508 png_save_uint_32(buf, width);
509 png_save_uint_32(buf + 4, height);
510 buf[8] = (png_byte)bit_depth;
511 buf[9] = (png_byte)color_type;
512 buf[10] = (png_byte)compression_type;
513 buf[11] = (png_byte)filter_type;
514 buf[12] = (png_byte)interlace_type;
515
516 /* Write the chunk */
517 png_write_chunk(png_ptr, (png_bytep)png_IHDR, buf, (png_size_t)13);
518
519 /* Initialize zlib with PNG info */
520 png_ptr->zstream.zalloc = png_zalloc;
521 png_ptr->zstream.zfree = png_zfree;
522 png_ptr->zstream.opaque = (voidpf)png_ptr;
523 if (!(png_ptr->do_filter))
524 {
525 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||
526 png_ptr->bit_depth < 8)
527 png_ptr->do_filter = PNG_FILTER_NONE;
528 else
529 png_ptr->do_filter = PNG_ALL_FILTERS;
530 }
531 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY))
532 {
533 if (png_ptr->do_filter != PNG_FILTER_NONE)
534 png_ptr->zlib_strategy = Z_FILTERED;
535 else
536 png_ptr->zlib_strategy = Z_DEFAULT_STRATEGY;
537 }
538 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_LEVEL))
539 png_ptr->zlib_level = Z_DEFAULT_COMPRESSION;
540 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL))
541 png_ptr->zlib_mem_level = 8;
542 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS))
543 png_ptr->zlib_window_bits = 15;
544 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_METHOD))
545 png_ptr->zlib_method = 8;
546 ret = deflateInit2(&png_ptr->zstream, png_ptr->zlib_level,
547 png_ptr->zlib_method, png_ptr->zlib_window_bits,
548 png_ptr->zlib_mem_level, png_ptr->zlib_strategy);
549 if (ret != Z_OK)
550 {
551 if (ret == Z_VERSION_ERROR) png_error(png_ptr,
552 "zlib failed to initialize compressor -- version error");
553 if (ret == Z_STREAM_ERROR) png_error(png_ptr,
554 "zlib failed to initialize compressor -- stream error");
555 if (ret == Z_MEM_ERROR) png_error(png_ptr,
556 "zlib failed to initialize compressor -- mem error");
557 png_error(png_ptr, "zlib failed to initialize compressor");
558 }
559 png_ptr->zstream.next_out = png_ptr->zbuf;
560 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
561 /* libpng is not interested in zstream.data_type */
562 /* Set it to a predefined value, to avoid its evaluation inside zlib */
563 png_ptr->zstream.data_type = Z_BINARY;
564
565 png_ptr->mode = PNG_HAVE_IHDR;
566}
567
568/* Write the palette. We are careful not to trust png_color to be in the
569 * correct order for PNG, so people can redefine it to any convenient
570 * structure.
571 */
572void /* PRIVATE */
573png_write_PLTE(png_structp png_ptr, png_colorp palette, png_uint_32 num_pal)
574{
575#ifdef PNG_USE_LOCAL_ARRAYS
576 PNG_PLTE;
577#endif
578 png_uint_32 max_palette_length, i;
579 png_colorp pal_ptr;
580 png_byte buf[3];
581
582 png_debug(1, "in png_write_PLTE");
583
584 max_palette_length = (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ?
585 (1 << png_ptr->bit_depth) : PNG_MAX_PALETTE_LENGTH;
586
587 if ((
588#ifdef PNG_MNG_FEATURES_SUPPORTED
589 !(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) &&
590#endif
591 num_pal == 0) || num_pal > max_palette_length)
592 {
593 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
594 {
595 png_error(png_ptr, "Invalid number of colors in palette");
596 }
597 else
598 {
599 png_warning(png_ptr, "Invalid number of colors in palette");
600 return;
601 }
602 }
603
604 if (!(png_ptr->color_type&PNG_COLOR_MASK_COLOR))
605 {
606 png_warning(png_ptr,
607 "Ignoring request to write a PLTE chunk in grayscale PNG");
608 return;
609 }
610
611 png_ptr->num_palette = (png_uint_16)num_pal;
612 png_debug1(3, "num_palette = %d", png_ptr->num_palette);
613
614 png_write_chunk_start(png_ptr, (png_bytep)png_PLTE,
615 (png_uint_32)(num_pal * 3));
616#ifdef PNG_POINTER_INDEXING_SUPPORTED
617 for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++)
618 {
619 buf[0] = pal_ptr->red;
620 buf[1] = pal_ptr->green;
621 buf[2] = pal_ptr->blue;
622 png_write_chunk_data(png_ptr, buf, (png_size_t)3);
623 }
624#else
625 /* This is a little slower but some buggy compilers need to do this
626 * instead
627 */
628 pal_ptr=palette;
629 for (i = 0; i < num_pal; i++)
630 {
631 buf[0] = pal_ptr[i].red;
632 buf[1] = pal_ptr[i].green;
633 buf[2] = pal_ptr[i].blue;
634 png_write_chunk_data(png_ptr, buf, (png_size_t)3);
635 }
636#endif
637 png_write_chunk_end(png_ptr);
638 png_ptr->mode |= PNG_HAVE_PLTE;
639}
640
641/* Write an IDAT chunk */
642void /* PRIVATE */
643png_write_IDAT(png_structp png_ptr, png_bytep data, png_size_t length)
644{
645#ifdef PNG_USE_LOCAL_ARRAYS
646 PNG_IDAT;
647#endif
648
649 png_debug(1, "in png_write_IDAT");
650
651 /* Optimize the CMF field in the zlib stream. */
652 /* This hack of the zlib stream is compliant to the stream specification. */
653 if (!(png_ptr->mode & PNG_HAVE_IDAT) &&
654 png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
655 {
656 unsigned int z_cmf = data[0]; /* zlib compression method and flags */
657 if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70)
658 {
659 /* Avoid memory underflows and multiplication overflows.
660 *
661 * The conditions below are practically always satisfied;
662 * however, they still must be checked.
663 */
664 if (length >= 2 &&
665 png_ptr->height < 16384 && png_ptr->width < 16384)
666 {
667 png_uint_32 uncompressed_idat_size = png_ptr->height *
668 ((png_ptr->width *
669 png_ptr->channels * png_ptr->bit_depth + 15) >> 3);
670 unsigned int z_cinfo = z_cmf >> 4;
671 unsigned int half_z_window_size = 1 << (z_cinfo + 7);
672 while (uncompressed_idat_size <= half_z_window_size &&
673 half_z_window_size >= 256)
674 {
675 z_cinfo--;
676 half_z_window_size >>= 1;
677 }
678 z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4);
679 if (data[0] != (png_byte)z_cmf)
680 {
681 data[0] = (png_byte)z_cmf;
682 data[1] &= 0xe0;
683 data[1] += (png_byte)(0x1f - ((z_cmf << 8) + data[1]) % 0x1f);
684 }
685 }
686 }
687 else
688 png_error(png_ptr,
689 "Invalid zlib compression method or flags in IDAT");
690 }
691
692 png_write_chunk(png_ptr, (png_bytep)png_IDAT, data, length);
693 png_ptr->mode |= PNG_HAVE_IDAT;
694}
695
696/* Write an IEND chunk */
697void /* PRIVATE */
698png_write_IEND(png_structp png_ptr)
699{
700#ifdef PNG_USE_LOCAL_ARRAYS
701 PNG_IEND;
702#endif
703
704 png_debug(1, "in png_write_IEND");
705
706 png_write_chunk(png_ptr, (png_bytep)png_IEND, png_bytep_NULL,
707 (png_size_t)0);
708 png_ptr->mode |= PNG_HAVE_IEND;
709}
710
711#ifdef PNG_WRITE_gAMA_SUPPORTED
712/* Write a gAMA chunk */
713#ifdef PNG_FLOATING_POINT_SUPPORTED
714void /* PRIVATE */
715png_write_gAMA(png_structp png_ptr, double file_gamma)
716{
717#ifdef PNG_USE_LOCAL_ARRAYS
718 PNG_gAMA;
719#endif
720 png_uint_32 igamma;
721 png_byte buf[4];
722
723 png_debug(1, "in png_write_gAMA");
724
725 /* file_gamma is saved in 1/100,000ths */
726 igamma = (png_uint_32)(file_gamma * 100000.0 + 0.5);
727 png_save_uint_32(buf, igamma);
728 png_write_chunk(png_ptr, (png_bytep)png_gAMA, buf, (png_size_t)4);
729}
730#endif
731#ifdef PNG_FIXED_POINT_SUPPORTED
732void /* PRIVATE */
733png_write_gAMA_fixed(png_structp png_ptr, png_fixed_point file_gamma)
734{
735#ifdef PNG_USE_LOCAL_ARRAYS
736 PNG_gAMA;
737#endif
738 png_byte buf[4];
739
740 png_debug(1, "in png_write_gAMA");
741
742 /* file_gamma is saved in 1/100,000ths */
743 png_save_uint_32(buf, (png_uint_32)file_gamma);
744 png_write_chunk(png_ptr, (png_bytep)png_gAMA, buf, (png_size_t)4);
745}
746#endif
747#endif
748
749#ifdef PNG_WRITE_sRGB_SUPPORTED
750/* Write a sRGB chunk */
751void /* PRIVATE */
752png_write_sRGB(png_structp png_ptr, int srgb_intent)
753{
754#ifdef PNG_USE_LOCAL_ARRAYS
755 PNG_sRGB;
756#endif
757 png_byte buf[1];
758
759 png_debug(1, "in png_write_sRGB");
760
761 if (srgb_intent >= PNG_sRGB_INTENT_LAST)
762 png_warning(png_ptr,
763 "Invalid sRGB rendering intent specified");
764 buf[0]=(png_byte)srgb_intent;
765 png_write_chunk(png_ptr, (png_bytep)png_sRGB, buf, (png_size_t)1);
766}
767#endif
768
769#ifdef PNG_WRITE_iCCP_SUPPORTED
770/* Write an iCCP chunk */
771void /* PRIVATE */
772png_write_iCCP(png_structp png_ptr, png_charp name, int compression_type,
773 png_charp profile, int profile_len)
774{
775#ifdef PNG_USE_LOCAL_ARRAYS
776 PNG_iCCP;
777#endif
778 png_size_t name_len;
779 png_charp new_name;
780 compression_state comp;
781 int embedded_profile_len = 0;
782
783 png_debug(1, "in png_write_iCCP");
784
785 comp.num_output_ptr = 0;
786 comp.max_output_ptr = 0;
787 comp.output_ptr = NULL;
788 comp.input = NULL;
789 comp.input_len = 0;
790
791 if ((name_len = png_check_keyword(png_ptr, name,
792 &new_name)) == 0)
793 return;
794
795 if (compression_type != PNG_COMPRESSION_TYPE_BASE)
796 png_warning(png_ptr, "Unknown compression type in iCCP chunk");
797
798 if (profile == NULL)
799 profile_len = 0;
800
801 if (profile_len > 3)
802 embedded_profile_len =
803 ((*( (png_bytep)profile ))<<24) |
804 ((*( (png_bytep)profile + 1))<<16) |
805 ((*( (png_bytep)profile + 2))<< 8) |
806 ((*( (png_bytep)profile + 3)) );
807
808 if (embedded_profile_len < 0)
809 {
810 png_warning(png_ptr,
811 "Embedded profile length in iCCP chunk is negative");
812 png_free(png_ptr, new_name);
813 return;
814 }
815
816 if (profile_len < embedded_profile_len)
817 {
818 png_warning(png_ptr,
819 "Embedded profile length too large in iCCP chunk");
820 png_free(png_ptr, new_name);
821 return;
822 }
823
824 if (profile_len > embedded_profile_len)
825 {
826 png_warning(png_ptr,
827 "Truncating profile to actual length in iCCP chunk");
828 profile_len = embedded_profile_len;
829 }
830
831 if (profile_len)
832 profile_len = png_text_compress(png_ptr, profile,
833 (png_size_t)profile_len, PNG_COMPRESSION_TYPE_BASE, &comp);
834
835 /* Make sure we include the NULL after the name and the compression type */
836 png_write_chunk_start(png_ptr, (png_bytep)png_iCCP,
837 (png_uint_32)(name_len + profile_len + 2));
838 new_name[name_len + 1] = 0x00;
839 png_write_chunk_data(png_ptr, (png_bytep)new_name,
840 (png_size_t)(name_len + 2));
841
842 if (profile_len)
843 png_write_compressed_data_out(png_ptr, &comp);
844
845 png_write_chunk_end(png_ptr);
846 png_free(png_ptr, new_name);
847}
848#endif
849
850#ifdef PNG_WRITE_sPLT_SUPPORTED
851/* Write a sPLT chunk */
852void /* PRIVATE */
853png_write_sPLT(png_structp png_ptr, png_sPLT_tp spalette)
854{
855#ifdef PNG_USE_LOCAL_ARRAYS
856 PNG_sPLT;
857#endif
858 png_size_t name_len;
859 png_charp new_name;
860 png_byte entrybuf[10];
861 int entry_size = (spalette->depth == 8 ? 6 : 10);
862 int palette_size = entry_size * spalette->nentries;
863 png_sPLT_entryp ep;
864#ifndef PNG_POINTER_INDEXING_SUPPORTED
865 int i;
866#endif
867
868 png_debug(1, "in png_write_sPLT");
869
870 if ((name_len = png_check_keyword(png_ptr,spalette->name, &new_name))==0)
871 return;
872
873 /* Make sure we include the NULL after the name */
874 png_write_chunk_start(png_ptr, (png_bytep)png_sPLT,
875 (png_uint_32)(name_len + 2 + palette_size));
876 png_write_chunk_data(png_ptr, (png_bytep)new_name,
877 (png_size_t)(name_len + 1));
878 png_write_chunk_data(png_ptr, (png_bytep)&spalette->depth, (png_size_t)1);
879
880 /* Loop through each palette entry, writing appropriately */
881#ifdef PNG_POINTER_INDEXING_SUPPORTED
882 for (ep = spalette->entries; ep<spalette->entries + spalette->nentries; ep++)
883 {
884 if (spalette->depth == 8)
885 {
886 entrybuf[0] = (png_byte)ep->red;
887 entrybuf[1] = (png_byte)ep->green;
888 entrybuf[2] = (png_byte)ep->blue;
889 entrybuf[3] = (png_byte)ep->alpha;
890 png_save_uint_16(entrybuf + 4, ep->frequency);
891 }
892 else
893 {
894 png_save_uint_16(entrybuf + 0, ep->red);
895 png_save_uint_16(entrybuf + 2, ep->green);
896 png_save_uint_16(entrybuf + 4, ep->blue);
897 png_save_uint_16(entrybuf + 6, ep->alpha);
898 png_save_uint_16(entrybuf + 8, ep->frequency);
899 }
900 png_write_chunk_data(png_ptr, entrybuf, (png_size_t)entry_size);
901 }
902#else
903 ep=spalette->entries;
904 for (i=0; i>spalette->nentries; i++)
905 {
906 if (spalette->depth == 8)
907 {
908 entrybuf[0] = (png_byte)ep[i].red;
909 entrybuf[1] = (png_byte)ep[i].green;
910 entrybuf[2] = (png_byte)ep[i].blue;
911 entrybuf[3] = (png_byte)ep[i].alpha;
912 png_save_uint_16(entrybuf + 4, ep[i].frequency);
913 }
914 else
915 {
916 png_save_uint_16(entrybuf + 0, ep[i].red);
917 png_save_uint_16(entrybuf + 2, ep[i].green);
918 png_save_uint_16(entrybuf + 4, ep[i].blue);
919 png_save_uint_16(entrybuf + 6, ep[i].alpha);
920 png_save_uint_16(entrybuf + 8, ep[i].frequency);
921 }
922 png_write_chunk_data(png_ptr, entrybuf, (png_size_t)entry_size);
923 }
924#endif
925
926 png_write_chunk_end(png_ptr);
927 png_free(png_ptr, new_name);
928}
929#endif
930
931#ifdef PNG_WRITE_sBIT_SUPPORTED
932/* Write the sBIT chunk */
933void /* PRIVATE */
934png_write_sBIT(png_structp png_ptr, png_color_8p sbit, int color_type)
935{
936#ifdef PNG_USE_LOCAL_ARRAYS
937 PNG_sBIT;
938#endif
939 png_byte buf[4];
940 png_size_t size;
941
942 png_debug(1, "in png_write_sBIT");
943
944 /* Make sure we don't depend upon the order of PNG_COLOR_8 */
945 if (color_type & PNG_COLOR_MASK_COLOR)
946 {
947 png_byte maxbits;
948
949 maxbits = (png_byte)(color_type==PNG_COLOR_TYPE_PALETTE ? 8 :
950 png_ptr->usr_bit_depth);
951 if (sbit->red == 0 || sbit->red > maxbits ||
952 sbit->green == 0 || sbit->green > maxbits ||
953 sbit->blue == 0 || sbit->blue > maxbits)
954 {
955 png_warning(png_ptr, "Invalid sBIT depth specified");
956 return;
957 }
958 buf[0] = sbit->red;
959 buf[1] = sbit->green;
960 buf[2] = sbit->blue;
961 size = 3;
962 }
963 else
964 {
965 if (sbit->gray == 0 || sbit->gray > png_ptr->usr_bit_depth)
966 {
967 png_warning(png_ptr, "Invalid sBIT depth specified");
968 return;
969 }
970 buf[0] = sbit->gray;
971 size = 1;
972 }
973
974 if (color_type & PNG_COLOR_MASK_ALPHA)
975 {
976 if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth)
977 {
978 png_warning(png_ptr, "Invalid sBIT depth specified");
979 return;
980 }
981 buf[size++] = sbit->alpha;
982 }
983
984 png_write_chunk(png_ptr, (png_bytep)png_sBIT, buf, size);
985}
986#endif
987
988#ifdef PNG_WRITE_cHRM_SUPPORTED
989/* Write the cHRM chunk */
990#ifdef PNG_FLOATING_POINT_SUPPORTED
991void /* PRIVATE */
992png_write_cHRM(png_structp png_ptr, double white_x, double white_y,
993 double red_x, double red_y, double green_x, double green_y,
994 double blue_x, double blue_y)
995{
996#ifdef PNG_USE_LOCAL_ARRAYS
997 PNG_cHRM;
998#endif
999 png_byte buf[32];
1000
1001 png_fixed_point int_white_x, int_white_y, int_red_x, int_red_y,
1002 int_green_x, int_green_y, int_blue_x, int_blue_y;
1003
1004 png_debug(1, "in png_write_cHRM");
1005
1006 int_white_x = (png_uint_32)(white_x * 100000.0 + 0.5);
1007 int_white_y = (png_uint_32)(white_y * 100000.0 + 0.5);
1008 int_red_x = (png_uint_32)(red_x * 100000.0 + 0.5);
1009 int_red_y = (png_uint_32)(red_y * 100000.0 + 0.5);
1010 int_green_x = (png_uint_32)(green_x * 100000.0 + 0.5);
1011 int_green_y = (png_uint_32)(green_y * 100000.0 + 0.5);
1012 int_blue_x = (png_uint_32)(blue_x * 100000.0 + 0.5);
1013 int_blue_y = (png_uint_32)(blue_y * 100000.0 + 0.5);
1014
1015#ifdef PNG_CHECK_cHRM_SUPPORTED
1016 if (png_check_cHRM_fixed(png_ptr, int_white_x, int_white_y,
1017 int_red_x, int_red_y, int_green_x, int_green_y, int_blue_x, int_blue_y))
1018#endif
1019 {
1020 /* Each value is saved in 1/100,000ths */
1021
1022 png_save_uint_32(buf, int_white_x);
1023 png_save_uint_32(buf + 4, int_white_y);
1024
1025 png_save_uint_32(buf + 8, int_red_x);
1026 png_save_uint_32(buf + 12, int_red_y);
1027
1028 png_save_uint_32(buf + 16, int_green_x);
1029 png_save_uint_32(buf + 20, int_green_y);
1030
1031 png_save_uint_32(buf + 24, int_blue_x);
1032 png_save_uint_32(buf + 28, int_blue_y);
1033
1034 png_write_chunk(png_ptr, (png_bytep)png_cHRM, buf, (png_size_t)32);
1035 }
1036}
1037#endif
1038#ifdef PNG_FIXED_POINT_SUPPORTED
1039void /* PRIVATE */
1040png_write_cHRM_fixed(png_structp png_ptr, png_fixed_point white_x,
1041 png_fixed_point white_y, png_fixed_point red_x, png_fixed_point red_y,
1042 png_fixed_point green_x, png_fixed_point green_y, png_fixed_point blue_x,
1043 png_fixed_point blue_y)
1044{
1045#ifdef PNG_USE_LOCAL_ARRAYS
1046 PNG_cHRM;
1047#endif
1048 png_byte buf[32];
1049
1050 png_debug(1, "in png_write_cHRM");
1051
1052 /* Each value is saved in 1/100,000ths */
1053#ifdef PNG_CHECK_cHRM_SUPPORTED
1054 if (png_check_cHRM_fixed(png_ptr, white_x, white_y, red_x, red_y,
1055 green_x, green_y, blue_x, blue_y))
1056#endif
1057 {
1058 png_save_uint_32(buf, (png_uint_32)white_x);
1059 png_save_uint_32(buf + 4, (png_uint_32)white_y);
1060
1061 png_save_uint_32(buf + 8, (png_uint_32)red_x);
1062 png_save_uint_32(buf + 12, (png_uint_32)red_y);
1063
1064 png_save_uint_32(buf + 16, (png_uint_32)green_x);
1065 png_save_uint_32(buf + 20, (png_uint_32)green_y);
1066
1067 png_save_uint_32(buf + 24, (png_uint_32)blue_x);
1068 png_save_uint_32(buf + 28, (png_uint_32)blue_y);
1069
1070 png_write_chunk(png_ptr, (png_bytep)png_cHRM, buf, (png_size_t)32);
1071 }
1072}
1073#endif
1074#endif
1075
1076#ifdef PNG_WRITE_tRNS_SUPPORTED
1077/* Write the tRNS chunk */
1078void /* PRIVATE */
1079png_write_tRNS(png_structp png_ptr, png_bytep trans, png_color_16p tran,
1080 int num_trans, int color_type)
1081{
1082#ifdef PNG_USE_LOCAL_ARRAYS
1083 PNG_tRNS;
1084#endif
1085 png_byte buf[6];
1086
1087 png_debug(1, "in png_write_tRNS");
1088
1089 if (color_type == PNG_COLOR_TYPE_PALETTE)
1090 {
1091 if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette)
1092 {
1093 png_warning(png_ptr, "Invalid number of transparent colors specified");
1094 return;
1095 }
1096 /* Write the chunk out as it is */
1097 png_write_chunk(png_ptr, (png_bytep)png_tRNS, trans,
1098 (png_size_t)num_trans);
1099 }
1100 else if (color_type == PNG_COLOR_TYPE_GRAY)
1101 {
1102 /* One 16 bit value */
1103 if (tran->gray >= (1 << png_ptr->bit_depth))
1104 {
1105 png_warning(png_ptr,
1106 "Ignoring attempt to write tRNS chunk out-of-range for bit_depth");
1107 return;
1108 }
1109 png_save_uint_16(buf, tran->gray);
1110 png_write_chunk(png_ptr, (png_bytep)png_tRNS, buf, (png_size_t)2);
1111 }
1112 else if (color_type == PNG_COLOR_TYPE_RGB)
1113 {
1114 /* Three 16 bit values */
1115 png_save_uint_16(buf, tran->red);
1116 png_save_uint_16(buf + 2, tran->green);
1117 png_save_uint_16(buf + 4, tran->blue);
1118 if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
1119 {
1120 png_warning(png_ptr,
1121 "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8");
1122 return;
1123 }
1124 png_write_chunk(png_ptr, (png_bytep)png_tRNS, buf, (png_size_t)6);
1125 }
1126 else
1127 {
1128 png_warning(png_ptr, "Can't write tRNS with an alpha channel");
1129 }
1130}
1131#endif
1132
1133#ifdef PNG_WRITE_bKGD_SUPPORTED
1134/* Write the background chunk */
1135void /* PRIVATE */
1136png_write_bKGD(png_structp png_ptr, png_color_16p back, int color_type)
1137{
1138#ifdef PNG_USE_LOCAL_ARRAYS
1139 PNG_bKGD;
1140#endif
1141 png_byte buf[6];
1142
1143 png_debug(1, "in png_write_bKGD");
1144
1145 if (color_type == PNG_COLOR_TYPE_PALETTE)
1146 {
1147 if (
1148#ifdef PNG_MNG_FEATURES_SUPPORTED
1149 (png_ptr->num_palette ||
1150 (!(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE))) &&
1151#endif
1152 back->index >= png_ptr->num_palette)
1153 {
1154 png_warning(png_ptr, "Invalid background palette index");
1155 return;
1156 }
1157 buf[0] = back->index;
1158 png_write_chunk(png_ptr, (png_bytep)png_bKGD, buf, (png_size_t)1);
1159 }
1160 else if (color_type & PNG_COLOR_MASK_COLOR)
1161 {
1162 png_save_uint_16(buf, back->red);
1163 png_save_uint_16(buf + 2, back->green);
1164 png_save_uint_16(buf + 4, back->blue);
1165 if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
1166 {
1167 png_warning(png_ptr,
1168 "Ignoring attempt to write 16-bit bKGD chunk when bit_depth is 8");
1169 return;
1170 }
1171 png_write_chunk(png_ptr, (png_bytep)png_bKGD, buf, (png_size_t)6);
1172 }
1173 else
1174 {
1175 if (back->gray >= (1 << png_ptr->bit_depth))
1176 {
1177 png_warning(png_ptr,
1178 "Ignoring attempt to write bKGD chunk out-of-range for bit_depth");
1179 return;
1180 }
1181 png_save_uint_16(buf, back->gray);
1182 png_write_chunk(png_ptr, (png_bytep)png_bKGD, buf, (png_size_t)2);
1183 }
1184}
1185#endif
1186
1187#ifdef PNG_WRITE_hIST_SUPPORTED
1188/* Write the histogram */
1189void /* PRIVATE */
1190png_write_hIST(png_structp png_ptr, png_uint_16p hist, int num_hist)
1191{
1192#ifdef PNG_USE_LOCAL_ARRAYS
1193 PNG_hIST;
1194#endif
1195 int i;
1196 png_byte buf[3];
1197
1198 png_debug(1, "in png_write_hIST");
1199
1200 if (num_hist > (int)png_ptr->num_palette)
1201 {
1202 png_debug2(3, "num_hist = %d, num_palette = %d", num_hist,
1203 png_ptr->num_palette);
1204 png_warning(png_ptr, "Invalid number of histogram entries specified");
1205 return;
1206 }
1207
1208 png_write_chunk_start(png_ptr, (png_bytep)png_hIST,
1209 (png_uint_32)(num_hist * 2));
1210 for (i = 0; i < num_hist; i++)
1211 {
1212 png_save_uint_16(buf, hist[i]);
1213 png_write_chunk_data(png_ptr, buf, (png_size_t)2);
1214 }
1215 png_write_chunk_end(png_ptr);
1216}
1217#endif
1218
1219#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \
1220 defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
1221/* Check that the tEXt or zTXt keyword is valid per PNG 1.0 specification,
1222 * and if invalid, correct the keyword rather than discarding the entire
1223 * chunk. The PNG 1.0 specification requires keywords 1-79 characters in
1224 * length, forbids leading or trailing whitespace, multiple internal spaces,
1225 * and the non-break space (0x80) from ISO 8859-1. Returns keyword length.
1226 *
1227 * The new_key is allocated to hold the corrected keyword and must be freed
1228 * by the calling routine. This avoids problems with trying to write to
1229 * static keywords without having to have duplicate copies of the strings.
1230 */
1231png_size_t /* PRIVATE */
1232png_check_keyword(png_structp png_ptr, png_charp key, png_charpp new_key)
1233{
1234 png_size_t key_len;
1235 png_charp kp, dp;
1236 int kflag;
1237 int kwarn=0;
1238
1239 png_debug(1, "in png_check_keyword");
1240
1241 *new_key = NULL;
1242
1243 if (key == NULL || (key_len = png_strlen(key)) == 0)
1244 {
1245 png_warning(png_ptr, "zero length keyword");
1246 return ((png_size_t)0);
1247 }
1248
1249 png_debug1(2, "Keyword to be checked is '%s'", key);
1250
1251 *new_key = (png_charp)png_malloc_warn(png_ptr, (png_uint_32)(key_len + 2));
1252 if (*new_key == NULL)
1253 {
1254 png_warning(png_ptr, "Out of memory while procesing keyword");
1255 return ((png_size_t)0);
1256 }
1257
1258 /* Replace non-printing characters with a blank and print a warning */
1259 for (kp = key, dp = *new_key; *kp != '\0'; kp++, dp++)
1260 {
1261 if ((png_byte)*kp < 0x20 ||
1262 ((png_byte)*kp > 0x7E && (png_byte)*kp < 0xA1))
1263 {
1264#if defined(PNG_STDIO_SUPPORTED) && !defined(_WIN32_WCE)
1265 char msg[40];
1266
1267 png_snprintf(msg, 40,
1268 "invalid keyword character 0x%02X", (png_byte)*kp);
1269 png_warning(png_ptr, msg);
1270#else
1271 png_warning(png_ptr, "invalid character in keyword");
1272#endif
1273 *dp = ' ';
1274 }
1275 else
1276 {
1277 *dp = *kp;
1278 }
1279 }
1280 *dp = '\0';
1281
1282 /* Remove any trailing white space. */
1283 kp = *new_key + key_len - 1;
1284 if (*kp == ' ')
1285 {
1286 png_warning(png_ptr, "trailing spaces removed from keyword");
1287
1288 while (*kp == ' ')
1289 {
1290 *(kp--) = '\0';
1291 key_len--;
1292 }
1293 }
1294
1295 /* Remove any leading white space. */
1296 kp = *new_key;
1297 if (*kp == ' ')
1298 {
1299 png_warning(png_ptr, "leading spaces removed from keyword");
1300
1301 while (*kp == ' ')
1302 {
1303 kp++;
1304 key_len--;
1305 }
1306 }
1307
1308 png_debug1(2, "Checking for multiple internal spaces in '%s'", kp);
1309
1310 /* Remove multiple internal spaces. */
1311 for (kflag = 0, dp = *new_key; *kp != '\0'; kp++)
1312 {
1313 if (*kp == ' ' && kflag == 0)
1314 {
1315 *(dp++) = *kp;
1316 kflag = 1;
1317 }
1318 else if (*kp == ' ')
1319 {
1320 key_len--;
1321 kwarn=1;
1322 }
1323 else
1324 {
1325 *(dp++) = *kp;
1326 kflag = 0;
1327 }
1328 }
1329 *dp = '\0';
1330 if (kwarn)
1331 png_warning(png_ptr, "extra interior spaces removed from keyword");
1332
1333 if (key_len == 0)
1334 {
1335 png_free(png_ptr, *new_key);
1336 *new_key=NULL;
1337 png_warning(png_ptr, "Zero length keyword");
1338 }
1339
1340 if (key_len > 79)
1341 {
1342 png_warning(png_ptr, "keyword length must be 1 - 79 characters");
1343 (*new_key)[79] = '\0';
1344 key_len = 79;
1345 }
1346
1347 return (key_len);
1348}
1349#endif
1350
1351#ifdef PNG_WRITE_tEXt_SUPPORTED
1352/* Write a tEXt chunk */
1353void /* PRIVATE */
1354png_write_tEXt(png_structp png_ptr, png_charp key, png_charp text,
1355 png_size_t text_len)
1356{
1357#ifdef PNG_USE_LOCAL_ARRAYS
1358 PNG_tEXt;
1359#endif
1360 png_size_t key_len;
1361 png_charp new_key;
1362
1363 png_debug(1, "in png_write_tEXt");
1364
1365 if ((key_len = png_check_keyword(png_ptr, key, &new_key))==0)
1366 return;
1367
1368 if (text == NULL || *text == '\0')
1369 text_len = 0;
1370 else
1371 text_len = png_strlen(text);
1372
1373 /* Make sure we include the 0 after the key */
1374 png_write_chunk_start(png_ptr, (png_bytep)png_tEXt,
1375 (png_uint_32)(key_len + text_len + 1));
1376 /*
1377 * We leave it to the application to meet PNG-1.0 requirements on the
1378 * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of
1379 * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them.
1380 * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
1381 */
1382 png_write_chunk_data(png_ptr, (png_bytep)new_key,
1383 (png_size_t)(key_len + 1));
1384 if (text_len)
1385 png_write_chunk_data(png_ptr, (png_bytep)text, (png_size_t)text_len);
1386
1387 png_write_chunk_end(png_ptr);
1388 png_free(png_ptr, new_key);
1389}
1390#endif
1391
1392#ifdef PNG_WRITE_zTXt_SUPPORTED
1393/* Write a compressed text chunk */
1394void /* PRIVATE */
1395png_write_zTXt(png_structp png_ptr, png_charp key, png_charp text,
1396 png_size_t text_len, int compression)
1397{
1398#ifdef PNG_USE_LOCAL_ARRAYS
1399 PNG_zTXt;
1400#endif
1401 png_size_t key_len;
1402 char buf[1];
1403 png_charp new_key;
1404 compression_state comp;
1405
1406 png_debug(1, "in png_write_zTXt");
1407
1408 comp.num_output_ptr = 0;
1409 comp.max_output_ptr = 0;
1410 comp.output_ptr = NULL;
1411 comp.input = NULL;
1412 comp.input_len = 0;
1413
1414 if ((key_len = png_check_keyword(png_ptr, key, &new_key))==0)
1415 {
1416 png_free(png_ptr, new_key);
1417 return;
1418 }
1419
1420 if (text == NULL || *text == '\0' || compression==PNG_TEXT_COMPRESSION_NONE)
1421 {
1422 png_write_tEXt(png_ptr, new_key, text, (png_size_t)0);
1423 png_free(png_ptr, new_key);
1424 return;
1425 }
1426
1427 text_len = png_strlen(text);
1428
1429 /* Compute the compressed data; do it now for the length */
1430 text_len = png_text_compress(png_ptr, text, text_len, compression,
1431 &comp);
1432
1433 /* Write start of chunk */
1434 png_write_chunk_start(png_ptr, (png_bytep)png_zTXt,
1435 (png_uint_32)(key_len+text_len + 2));
1436 /* Write key */
1437 png_write_chunk_data(png_ptr, (png_bytep)new_key,
1438 (png_size_t)(key_len + 1));
1439 png_free(png_ptr, new_key);
1440
1441 buf[0] = (png_byte)compression;
1442 /* Write compression */
1443 png_write_chunk_data(png_ptr, (png_bytep)buf, (png_size_t)1);
1444 /* Write the compressed data */
1445 png_write_compressed_data_out(png_ptr, &comp);
1446
1447 /* Close the chunk */
1448 png_write_chunk_end(png_ptr);
1449}
1450#endif
1451
1452#ifdef PNG_WRITE_iTXt_SUPPORTED
1453/* Write an iTXt chunk */
1454void /* PRIVATE */
1455png_write_iTXt(png_structp png_ptr, int compression, png_charp key,
1456 png_charp lang, png_charp lang_key, png_charp text)
1457{
1458#ifdef PNG_USE_LOCAL_ARRAYS
1459 PNG_iTXt;
1460#endif
1461 png_size_t lang_len, key_len, lang_key_len, text_len;
1462 png_charp new_lang;
1463 png_charp new_key = NULL;
1464 png_byte cbuf[2];
1465 compression_state comp;
1466
1467 png_debug(1, "in png_write_iTXt");
1468
1469 comp.num_output_ptr = 0;
1470 comp.max_output_ptr = 0;
1471 comp.output_ptr = NULL;
1472 comp.input = NULL;
1473
1474 if ((key_len = png_check_keyword(png_ptr, key, &new_key))==0)
1475 return;
1476
1477 if ((lang_len = png_check_keyword(png_ptr, lang, &new_lang))==0)
1478 {
1479 png_warning(png_ptr, "Empty language field in iTXt chunk");
1480 new_lang = NULL;
1481 lang_len = 0;
1482 }
1483
1484 if (lang_key == NULL)
1485 lang_key_len = 0;
1486 else
1487 lang_key_len = png_strlen(lang_key);
1488
1489 if (text == NULL)
1490 text_len = 0;
1491 else
1492 text_len = png_strlen(text);
1493
1494 /* Compute the compressed data; do it now for the length */
1495 text_len = png_text_compress(png_ptr, text, text_len, compression-2,
1496 &comp);
1497
1498
1499 /* Make sure we include the compression flag, the compression byte,
1500 * and the NULs after the key, lang, and lang_key parts */
1501
1502 png_write_chunk_start(png_ptr, (png_bytep)png_iTXt,
1503 (png_uint_32)(
1504 5 /* comp byte, comp flag, terminators for key, lang and lang_key */
1505 + key_len
1506 + lang_len
1507 + lang_key_len
1508 + text_len));
1509
1510 /* We leave it to the application to meet PNG-1.0 requirements on the
1511 * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of
1512 * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them.
1513 * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
1514 */
1515 png_write_chunk_data(png_ptr, (png_bytep)new_key,
1516 (png_size_t)(key_len + 1));
1517
1518 /* Set the compression flag */
1519 if (compression == PNG_ITXT_COMPRESSION_NONE || \
1520 compression == PNG_TEXT_COMPRESSION_NONE)
1521 cbuf[0] = 0;
1522 else /* compression == PNG_ITXT_COMPRESSION_zTXt */
1523 cbuf[0] = 1;
1524 /* Set the compression method */
1525 cbuf[1] = 0;
1526 png_write_chunk_data(png_ptr, cbuf, (png_size_t)2);
1527
1528 cbuf[0] = 0;
1529 png_write_chunk_data(png_ptr, (new_lang ? (png_bytep)new_lang : cbuf),
1530 (png_size_t)(lang_len + 1));
1531 png_write_chunk_data(png_ptr, (lang_key ? (png_bytep)lang_key : cbuf),
1532 (png_size_t)(lang_key_len + 1));
1533 png_write_compressed_data_out(png_ptr, &comp);
1534
1535 png_write_chunk_end(png_ptr);
1536 png_free(png_ptr, new_key);
1537 png_free(png_ptr, new_lang);
1538}
1539#endif
1540
1541#ifdef PNG_WRITE_oFFs_SUPPORTED
1542/* Write the oFFs chunk */
1543void /* PRIVATE */
1544png_write_oFFs(png_structp png_ptr, png_int_32 x_offset, png_int_32 y_offset,
1545 int unit_type)
1546{
1547#ifdef PNG_USE_LOCAL_ARRAYS
1548 PNG_oFFs;
1549#endif
1550 png_byte buf[9];
1551
1552 png_debug(1, "in png_write_oFFs");
1553
1554 if (unit_type >= PNG_OFFSET_LAST)
1555 png_warning(png_ptr, "Unrecognized unit type for oFFs chunk");
1556
1557 png_save_int_32(buf, x_offset);
1558 png_save_int_32(buf + 4, y_offset);
1559 buf[8] = (png_byte)unit_type;
1560
1561 png_write_chunk(png_ptr, (png_bytep)png_oFFs, buf, (png_size_t)9);
1562}
1563#endif
1564#ifdef PNG_WRITE_pCAL_SUPPORTED
1565/* Write the pCAL chunk (described in the PNG extensions document) */
1566void /* PRIVATE */
1567png_write_pCAL(png_structp png_ptr, png_charp purpose, png_int_32 X0,
1568 png_int_32 X1, int type, int nparams, png_charp units, png_charpp params)
1569{
1570#ifdef PNG_USE_LOCAL_ARRAYS
1571 PNG_pCAL;
1572#endif
1573 png_size_t purpose_len, units_len, total_len;
1574 png_uint_32p params_len;
1575 png_byte buf[10];
1576 png_charp new_purpose;
1577 int i;
1578
1579 png_debug1(1, "in png_write_pCAL (%d parameters)", nparams);
1580
1581 if (type >= PNG_EQUATION_LAST)
1582 png_warning(png_ptr, "Unrecognized equation type for pCAL chunk");
1583
1584 purpose_len = png_check_keyword(png_ptr, purpose, &new_purpose) + 1;
1585 png_debug1(3, "pCAL purpose length = %d", (int)purpose_len);
1586 units_len = png_strlen(units) + (nparams == 0 ? 0 : 1);
1587 png_debug1(3, "pCAL units length = %d", (int)units_len);
1588 total_len = purpose_len + units_len + 10;
1589
1590 params_len = (png_uint_32p)png_malloc(png_ptr,
1591 (png_uint_32)(nparams * png_sizeof(png_uint_32)));
1592
1593 /* Find the length of each parameter, making sure we don't count the
1594 null terminator for the last parameter. */
1595 for (i = 0; i < nparams; i++)
1596 {
1597 params_len[i] = png_strlen(params[i]) + (i == nparams - 1 ? 0 : 1);
1598 png_debug2(3, "pCAL parameter %d length = %lu", i,
1599 (unsigned long) params_len[i]);
1600 total_len += (png_size_t)params_len[i];
1601 }
1602
1603 png_debug1(3, "pCAL total length = %d", (int)total_len);
1604 png_write_chunk_start(png_ptr, (png_bytep)png_pCAL, (png_uint_32)total_len);
1605 png_write_chunk_data(png_ptr, (png_bytep)new_purpose,
1606 (png_size_t)purpose_len);
1607 png_save_int_32(buf, X0);
1608 png_save_int_32(buf + 4, X1);
1609 buf[8] = (png_byte)type;
1610 buf[9] = (png_byte)nparams;
1611 png_write_chunk_data(png_ptr, buf, (png_size_t)10);
1612 png_write_chunk_data(png_ptr, (png_bytep)units, (png_size_t)units_len);
1613
1614 png_free(png_ptr, new_purpose);
1615
1616 for (i = 0; i < nparams; i++)
1617 {
1618 png_write_chunk_data(png_ptr, (png_bytep)params[i],
1619 (png_size_t)params_len[i]);
1620 }
1621
1622 png_free(png_ptr, params_len);
1623 png_write_chunk_end(png_ptr);
1624}
1625#endif
1626
1627#ifdef PNG_WRITE_sCAL_SUPPORTED
1628/* Write the sCAL chunk */
1629#if defined(PNG_FLOATING_POINT_SUPPORTED) && defined(PNG_STDIO_SUPPORTED)
1630void /* PRIVATE */
1631png_write_sCAL(png_structp png_ptr, int unit, double width, double height)
1632{
1633#ifdef PNG_USE_LOCAL_ARRAYS
1634 PNG_sCAL;
1635#endif
1636 char buf[64];
1637 png_size_t total_len;
1638
1639 png_debug(1, "in png_write_sCAL");
1640
1641 buf[0] = (char)unit;
1642#ifdef _WIN32_WCE
1643/* sprintf() function is not supported on WindowsCE */
1644 {
1645 wchar_t wc_buf[32];
1646 size_t wc_len;
1647 swprintf(wc_buf, TEXT("%12.12e"), width);
1648 wc_len = wcslen(wc_buf);
1649 WideCharToMultiByte(CP_ACP, 0, wc_buf, -1, buf + 1, wc_len, NULL,
1650 NULL);
1651 total_len = wc_len + 2;
1652 swprintf(wc_buf, TEXT("%12.12e"), height);
1653 wc_len = wcslen(wc_buf);
1654 WideCharToMultiByte(CP_ACP, 0, wc_buf, -1, buf + total_len, wc_len,
1655 NULL, NULL);
1656 total_len += wc_len;
1657 }
1658#else
1659 png_snprintf(buf + 1, 63, "%12.12e", width);
1660 total_len = 1 + png_strlen(buf + 1) + 1;
1661 png_snprintf(buf + total_len, 64-total_len, "%12.12e", height);
1662 total_len += png_strlen(buf + total_len);
1663#endif
1664
1665 png_debug1(3, "sCAL total length = %u", (unsigned int)total_len);
1666 png_write_chunk(png_ptr, (png_bytep)png_sCAL, (png_bytep)buf, total_len);
1667}
1668#else
1669#ifdef PNG_FIXED_POINT_SUPPORTED
1670void /* PRIVATE */
1671png_write_sCAL_s(png_structp png_ptr, int unit, png_charp width,
1672 png_charp height)
1673{
1674#ifdef PNG_USE_LOCAL_ARRAYS
1675 PNG_sCAL;
1676#endif
1677 png_byte buf[64];
1678 png_size_t wlen, hlen, total_len;
1679
1680 png_debug(1, "in png_write_sCAL_s");
1681
1682 wlen = png_strlen(width);
1683 hlen = png_strlen(height);
1684 total_len = wlen + hlen + 2;
1685 if (total_len > 64)
1686 {
1687 png_warning(png_ptr, "Can't write sCAL (buffer too small)");
1688 return;
1689 }
1690
1691 buf[0] = (png_byte)unit;
1692 png_memcpy(buf + 1, width, wlen + 1); /* Append the '\0' here */
1693 png_memcpy(buf + wlen + 2, height, hlen); /* Do NOT append the '\0' here */
1694
1695 png_debug1(3, "sCAL total length = %u", (unsigned int)total_len);
1696 png_write_chunk(png_ptr, (png_bytep)png_sCAL, buf, total_len);
1697}
1698#endif
1699#endif
1700#endif
1701
1702#ifdef PNG_WRITE_pHYs_SUPPORTED
1703/* Write the pHYs chunk */
1704void /* PRIVATE */
1705png_write_pHYs(png_structp png_ptr, png_uint_32 x_pixels_per_unit,
1706 png_uint_32 y_pixels_per_unit,
1707 int unit_type)
1708{
1709#ifdef PNG_USE_LOCAL_ARRAYS
1710 PNG_pHYs;
1711#endif
1712 png_byte buf[9];
1713
1714 png_debug(1, "in png_write_pHYs");
1715
1716 if (unit_type >= PNG_RESOLUTION_LAST)
1717 png_warning(png_ptr, "Unrecognized unit type for pHYs chunk");
1718
1719 png_save_uint_32(buf, x_pixels_per_unit);
1720 png_save_uint_32(buf + 4, y_pixels_per_unit);
1721 buf[8] = (png_byte)unit_type;
1722
1723 png_write_chunk(png_ptr, (png_bytep)png_pHYs, buf, (png_size_t)9);
1724}
1725#endif
1726
1727#ifdef PNG_WRITE_tIME_SUPPORTED
1728/* Write the tIME chunk. Use either png_convert_from_struct_tm()
1729 * or png_convert_from_time_t(), or fill in the structure yourself.
1730 */
1731void /* PRIVATE */
1732png_write_tIME(png_structp png_ptr, png_timep mod_time)
1733{
1734#ifdef PNG_USE_LOCAL_ARRAYS
1735 PNG_tIME;
1736#endif
1737 png_byte buf[7];
1738
1739 png_debug(1, "in png_write_tIME");
1740
1741 if (mod_time->month > 12 || mod_time->month < 1 ||
1742 mod_time->day > 31 || mod_time->day < 1 ||
1743 mod_time->hour > 23 || mod_time->second > 60)
1744 {
1745 png_warning(png_ptr, "Invalid time specified for tIME chunk");
1746 return;
1747 }
1748
1749 png_save_uint_16(buf, mod_time->year);
1750 buf[2] = mod_time->month;
1751 buf[3] = mod_time->day;
1752 buf[4] = mod_time->hour;
1753 buf[5] = mod_time->minute;
1754 buf[6] = mod_time->second;
1755
1756 png_write_chunk(png_ptr, (png_bytep)png_tIME, buf, (png_size_t)7);
1757}
1758#endif
1759
1760/* Initializes the row writing capability of libpng */
1761void /* PRIVATE */
1762png_write_start_row(png_structp png_ptr)
1763{
1764#ifdef PNG_WRITE_INTERLACING_SUPPORTED
1765#ifndef PNG_USE_GLOBAL_ARRAYS
1766 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
1767
1768 /* Start of interlace block */
1769 int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
1770
1771 /* Offset to next interlace block */
1772 int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
1773
1774 /* Start of interlace block in the y direction */
1775 int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
1776
1777 /* Offset to next interlace block in the y direction */
1778 int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
1779#endif
1780#endif
1781
1782 png_size_t buf_size;
1783
1784 png_debug(1, "in png_write_start_row");
1785
1786 buf_size = (png_size_t)(PNG_ROWBYTES(
1787 png_ptr->usr_channels*png_ptr->usr_bit_depth, png_ptr->width) + 1);
1788
1789 /* Set up row buffer */
1790 png_ptr->row_buf = (png_bytep)png_malloc(png_ptr,
1791 (png_uint_32)buf_size);
1792 png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE;
1793
1794#ifdef PNG_WRITE_FILTER_SUPPORTED
1795 /* Set up filtering buffer, if using this filter */
1796 if (png_ptr->do_filter & PNG_FILTER_SUB)
1797 {
1798 png_ptr->sub_row = (png_bytep)png_malloc(png_ptr,
1799 (png_uint_32)(png_ptr->rowbytes + 1));
1800 png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
1801 }
1802
1803 /* We only need to keep the previous row if we are using one of these. */
1804 if (png_ptr->do_filter & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH))
1805 {
1806 /* Set up previous row buffer */
1807 png_ptr->prev_row = (png_bytep)png_calloc(png_ptr,
1808 (png_uint_32)buf_size);
1809
1810 if (png_ptr->do_filter & PNG_FILTER_UP)
1811 {
1812 png_ptr->up_row = (png_bytep)png_malloc(png_ptr,
1813 (png_uint_32)(png_ptr->rowbytes + 1));
1814 png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
1815 }
1816
1817 if (png_ptr->do_filter & PNG_FILTER_AVG)
1818 {
1819 png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
1820 (png_uint_32)(png_ptr->rowbytes + 1));
1821 png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
1822 }
1823
1824 if (png_ptr->do_filter & PNG_FILTER_PAETH)
1825 {
1826 png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,
1827 (png_uint_32)(png_ptr->rowbytes + 1));
1828 png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
1829 }
1830 }
1831#endif /* PNG_WRITE_FILTER_SUPPORTED */
1832
1833#ifdef PNG_WRITE_INTERLACING_SUPPORTED
1834 /* If interlaced, we need to set up width and height of pass */
1835 if (png_ptr->interlaced)
1836 {
1837 if (!(png_ptr->transformations & PNG_INTERLACE))
1838 {
1839 png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
1840 png_pass_ystart[0]) / png_pass_yinc[0];
1841 png_ptr->usr_width = (png_ptr->width + png_pass_inc[0] - 1 -
1842 png_pass_start[0]) / png_pass_inc[0];
1843 }
1844 else
1845 {
1846 png_ptr->num_rows = png_ptr->height;
1847 png_ptr->usr_width = png_ptr->width;
1848 }
1849 }
1850 else
1851#endif
1852 {
1853 png_ptr->num_rows = png_ptr->height;
1854 png_ptr->usr_width = png_ptr->width;
1855 }
1856 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1857 png_ptr->zstream.next_out = png_ptr->zbuf;
1858}
1859
1860/* Internal use only. Called when finished processing a row of data. */
1861void /* PRIVATE */
1862png_write_finish_row(png_structp png_ptr)
1863{
1864#ifdef PNG_WRITE_INTERLACING_SUPPORTED
1865#ifndef PNG_USE_GLOBAL_ARRAYS
1866 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
1867
1868 /* Start of interlace block */
1869 int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
1870
1871 /* Offset to next interlace block */
1872 int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
1873
1874 /* Start of interlace block in the y direction */
1875 int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
1876
1877 /* Offset to next interlace block in the y direction */
1878 int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
1879#endif
1880#endif
1881
1882 int ret;
1883
1884 png_debug(1, "in png_write_finish_row");
1885
1886 /* Next row */
1887 png_ptr->row_number++;
1888
1889 /* See if we are done */
1890 if (png_ptr->row_number < png_ptr->num_rows)
1891 return;
1892
1893#ifdef PNG_WRITE_INTERLACING_SUPPORTED
1894 /* If interlaced, go to next pass */
1895 if (png_ptr->interlaced)
1896 {
1897 png_ptr->row_number = 0;
1898 if (png_ptr->transformations & PNG_INTERLACE)
1899 {
1900 png_ptr->pass++;
1901 }
1902 else
1903 {
1904 /* Loop until we find a non-zero width or height pass */
1905 do
1906 {
1907 png_ptr->pass++;
1908 if (png_ptr->pass >= 7)
1909 break;
1910 png_ptr->usr_width = (png_ptr->width +
1911 png_pass_inc[png_ptr->pass] - 1 -
1912 png_pass_start[png_ptr->pass]) /
1913 png_pass_inc[png_ptr->pass];
1914 png_ptr->num_rows = (png_ptr->height +
1915 png_pass_yinc[png_ptr->pass] - 1 -
1916 png_pass_ystart[png_ptr->pass]) /
1917 png_pass_yinc[png_ptr->pass];
1918 if (png_ptr->transformations & PNG_INTERLACE)
1919 break;
1920 } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0);
1921
1922 }
1923
1924 /* Reset the row above the image for the next pass */
1925 if (png_ptr->pass < 7)
1926 {
1927 if (png_ptr->prev_row != NULL)
1928 png_memset(png_ptr->prev_row, 0,
1929 (png_size_t)(PNG_ROWBYTES(png_ptr->usr_channels*
1930 png_ptr->usr_bit_depth, png_ptr->width)) + 1);
1931 return;
1932 }
1933 }
1934#endif
1935
1936 /* If we get here, we've just written the last row, so we need
1937 to flush the compressor */
1938 do
1939 {
1940 /* Tell the compressor we are done */
1941 ret = deflate(&png_ptr->zstream, Z_FINISH);
1942 /* Check for an error */
1943 if (ret == Z_OK)
1944 {
1945 /* Check to see if we need more room */
1946 if (!(png_ptr->zstream.avail_out))
1947 {
1948 png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
1949 png_ptr->zstream.next_out = png_ptr->zbuf;
1950 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1951 }
1952 }
1953 else if (ret != Z_STREAM_END)
1954 {
1955 if (png_ptr->zstream.msg != NULL)
1956 png_error(png_ptr, png_ptr->zstream.msg);
1957 else
1958 png_error(png_ptr, "zlib error");
1959 }
1960 } while (ret != Z_STREAM_END);
1961
1962 /* Write any extra space */
1963 if (png_ptr->zstream.avail_out < png_ptr->zbuf_size)
1964 {
1965 png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size -
1966 png_ptr->zstream.avail_out);
1967 }
1968
1969 deflateReset(&png_ptr->zstream);
1970 png_ptr->zstream.data_type = Z_BINARY;
1971}
1972
1973#ifdef PNG_WRITE_INTERLACING_SUPPORTED
1974/* Pick out the correct pixels for the interlace pass.
1975 * The basic idea here is to go through the row with a source
1976 * pointer and a destination pointer (sp and dp), and copy the
1977 * correct pixels for the pass. As the row gets compacted,
1978 * sp will always be >= dp, so we should never overwrite anything.
1979 * See the default: case for the easiest code to understand.
1980 */
1981void /* PRIVATE */
1982png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
1983{
1984 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
1985
1986#ifndef PNG_USE_GLOBAL_ARRAYS
1987 /* Start of interlace block */
1988 int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
1989
1990 /* Offset to next interlace block */
1991 int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
1992#endif
1993
1994 png_debug(1, "in png_do_write_interlace");
1995
1996 /* We don't have to do anything on the last pass (6) */
1997#ifdef PNG_USELESS_TESTS_SUPPORTED
1998 if (row != NULL && row_info != NULL && pass < 6)
1999#else
2000 if (pass < 6)
2001#endif
2002 {
2003 /* Each pixel depth is handled separately */
2004 switch (row_info->pixel_depth)
2005 {
2006 case 1:
2007 {
2008 png_bytep sp;
2009 png_bytep dp;
2010 int shift;
2011 int d;
2012 int value;
2013 png_uint_32 i;
2014 png_uint_32 row_width = row_info->width;
2015
2016 dp = row;
2017 d = 0;
2018 shift = 7;
2019 for (i = png_pass_start[pass]; i < row_width;
2020 i += png_pass_inc[pass])
2021 {
2022 sp = row + (png_size_t)(i >> 3);
2023 value = (int)(*sp >> (7 - (int)(i & 0x07))) & 0x01;
2024 d |= (value << shift);
2025
2026 if (shift == 0)
2027 {
2028 shift = 7;
2029 *dp++ = (png_byte)d;
2030 d = 0;
2031 }
2032 else
2033 shift--;
2034
2035 }
2036 if (shift != 7)
2037 *dp = (png_byte)d;
2038 break;
2039 }
2040 case 2:
2041 {
2042 png_bytep sp;
2043 png_bytep dp;
2044 int shift;
2045 int d;
2046 int value;
2047 png_uint_32 i;
2048 png_uint_32 row_width = row_info->width;
2049
2050 dp = row;
2051 shift = 6;
2052 d = 0;
2053 for (i = png_pass_start[pass]; i < row_width;
2054 i += png_pass_inc[pass])
2055 {
2056 sp = row + (png_size_t)(i >> 2);
2057 value = (*sp >> ((3 - (int)(i & 0x03)) << 1)) & 0x03;
2058 d |= (value << shift);
2059
2060 if (shift == 0)
2061 {
2062 shift = 6;
2063 *dp++ = (png_byte)d;
2064 d = 0;
2065 }
2066 else
2067 shift -= 2;
2068 }
2069 if (shift != 6)
2070 *dp = (png_byte)d;
2071 break;
2072 }
2073 case 4:
2074 {
2075 png_bytep sp;
2076 png_bytep dp;
2077 int shift;
2078 int d;
2079 int value;
2080 png_uint_32 i;
2081 png_uint_32 row_width = row_info->width;
2082
2083 dp = row;
2084 shift = 4;
2085 d = 0;
2086 for (i = png_pass_start[pass]; i < row_width;
2087 i += png_pass_inc[pass])
2088 {
2089 sp = row + (png_size_t)(i >> 1);
2090 value = (*sp >> ((1 - (int)(i & 0x01)) << 2)) & 0x0f;
2091 d |= (value << shift);
2092
2093 if (shift == 0)
2094 {
2095 shift = 4;
2096 *dp++ = (png_byte)d;
2097 d = 0;
2098 }
2099 else
2100 shift -= 4;
2101 }
2102 if (shift != 4)
2103 *dp = (png_byte)d;
2104 break;
2105 }
2106 default:
2107 {
2108 png_bytep sp;
2109 png_bytep dp;
2110 png_uint_32 i;
2111 png_uint_32 row_width = row_info->width;
2112 png_size_t pixel_bytes;
2113
2114 /* Start at the beginning */
2115 dp = row;
2116 /* Find out how many bytes each pixel takes up */
2117 pixel_bytes = (row_info->pixel_depth >> 3);
2118 /* Loop through the row, only looking at the pixels that
2119 matter */
2120 for (i = png_pass_start[pass]; i < row_width;
2121 i += png_pass_inc[pass])
2122 {
2123 /* Find out where the original pixel is */
2124 sp = row + (png_size_t)i * pixel_bytes;
2125 /* Move the pixel */
2126 if (dp != sp)
2127 png_memcpy(dp, sp, pixel_bytes);
2128 /* Next pixel */
2129 dp += pixel_bytes;
2130 }
2131 break;
2132 }
2133 }
2134 /* Set new row width */
2135 row_info->width = (row_info->width +
2136 png_pass_inc[pass] - 1 -
2137 png_pass_start[pass]) /
2138 png_pass_inc[pass];
2139 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
2140 row_info->width);
2141 }
2142}
2143#endif
2144
2145/* This filters the row, chooses which filter to use, if it has not already
2146 * been specified by the application, and then writes the row out with the
2147 * chosen filter.
2148 */
2149#define PNG_MAXSUM (((png_uint_32)(-1)) >> 1)
2150#define PNG_HISHIFT 10
2151#define PNG_LOMASK ((png_uint_32)0xffffL)
2152#define PNG_HIMASK ((png_uint_32)(~PNG_LOMASK >> PNG_HISHIFT))
2153void /* PRIVATE */
2154png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
2155{
2156 png_bytep best_row;
2157#ifdef PNG_WRITE_FILTER_SUPPORTED
2158 png_bytep prev_row, row_buf;
2159 png_uint_32 mins, bpp;
2160 png_byte filter_to_do = png_ptr->do_filter;
2161 png_uint_32 row_bytes = row_info->rowbytes;
2162
2163 png_debug(1, "in png_write_find_filter");
2164
2165 /* Find out how many bytes offset each pixel is */
2166 bpp = (row_info->pixel_depth + 7) >> 3;
2167
2168 prev_row = png_ptr->prev_row;
2169#endif
2170 best_row = png_ptr->row_buf;
2171#ifdef PNG_WRITE_FILTER_SUPPORTED
2172 row_buf = best_row;
2173 mins = PNG_MAXSUM;
2174
2175 /* The prediction method we use is to find which method provides the
2176 * smallest value when summing the absolute values of the distances
2177 * from zero, using anything >= 128 as negative numbers. This is known
2178 * as the "minimum sum of absolute differences" heuristic. Other
2179 * heuristics are the "weighted minimum sum of absolute differences"
2180 * (experimental and can in theory improve compression), and the "zlib
2181 * predictive" method (not implemented yet), which does test compressions
2182 * of lines using different filter methods, and then chooses the
2183 * (series of) filter(s) that give minimum compressed data size (VERY
2184 * computationally expensive).
2185 *
2186 * GRR 980525: consider also
2187 * (1) minimum sum of absolute differences from running average (i.e.,
2188 * keep running sum of non-absolute differences & count of bytes)
2189 * [track dispersion, too? restart average if dispersion too large?]
2190 * (1b) minimum sum of absolute differences from sliding average, probably
2191 * with window size <= deflate window (usually 32K)
2192 * (2) minimum sum of squared differences from zero or running average
2193 * (i.e., ~ root-mean-square approach)
2194 */
2195
2196
2197 /* We don't need to test the 'no filter' case if this is the only filter
2198 * that has been chosen, as it doesn't actually do anything to the data.
2199 */
2200 if ((filter_to_do & PNG_FILTER_NONE) &&
2201 filter_to_do != PNG_FILTER_NONE)
2202 {
2203 png_bytep rp;
2204 png_uint_32 sum = 0;
2205 png_uint_32 i;
2206 int v;
2207
2208 for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
2209 {
2210 v = *rp;
2211 sum += (v < 128) ? v : 256 - v;
2212 }
2213
2214 mins = sum;
2215 }
2216
2217 /* Sub filter */
2218 if (filter_to_do == PNG_FILTER_SUB)
2219 /* It's the only filter so no testing is needed */
2220 {
2221 png_bytep rp, lp, dp;
2222 png_uint_32 i;
2223 for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
2224 i++, rp++, dp++)
2225 {
2226 *dp = *rp;
2227 }
2228 for (lp = row_buf + 1; i < row_bytes;
2229 i++, rp++, lp++, dp++)
2230 {
2231 *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
2232 }
2233 best_row = png_ptr->sub_row;
2234 }
2235
2236 else if (filter_to_do & PNG_FILTER_SUB)
2237 {
2238 png_bytep rp, dp, lp;
2239 png_uint_32 sum = 0, lmins = mins;
2240 png_uint_32 i;
2241 int v;
2242
2243 for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
2244 i++, rp++, dp++)
2245 {
2246 v = *dp = *rp;
2247
2248 sum += (v < 128) ? v : 256 - v;
2249 }
2250 for (lp = row_buf + 1; i < row_bytes;
2251 i++, rp++, lp++, dp++)
2252 {
2253 v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
2254
2255 sum += (v < 128) ? v : 256 - v;
2256
2257 if (sum > lmins) /* We are already worse, don't continue. */
2258 break;
2259 }
2260
2261 if (sum < mins)
2262 {
2263 mins = sum;
2264 best_row = png_ptr->sub_row;
2265 }
2266 }
2267
2268 /* Up filter */
2269 if (filter_to_do == PNG_FILTER_UP)
2270 {
2271 png_bytep rp, dp, pp;
2272 png_uint_32 i;
2273
2274 for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
2275 pp = prev_row + 1; i < row_bytes;
2276 i++, rp++, pp++, dp++)
2277 {
2278 *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
2279 }
2280 best_row = png_ptr->up_row;
2281 }
2282
2283 else if (filter_to_do & PNG_FILTER_UP)
2284 {
2285 png_bytep rp, dp, pp;
2286 png_uint_32 sum = 0, lmins = mins;
2287 png_uint_32 i;
2288 int v;
2289
2290 for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
2291 pp = prev_row + 1; i < row_bytes; i++)
2292 {
2293 v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
2294
2295 sum += (v < 128) ? v : 256 - v;
2296
2297 if (sum > lmins) /* We are already worse, don't continue. */
2298 break;
2299 }
2300
2301 if (sum < mins)
2302 {
2303 mins = sum;
2304 best_row = png_ptr->up_row;
2305 }
2306 }
2307
2308 /* Avg filter */
2309 if (filter_to_do == PNG_FILTER_AVG)
2310 {
2311 png_bytep rp, dp, pp, lp;
2312 png_uint_32 i;
2313 for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
2314 pp = prev_row + 1; i < bpp; i++)
2315 {
2316 *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
2317 }
2318 for (lp = row_buf + 1; i < row_bytes; i++)
2319 {
2320 *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
2321 & 0xff);
2322 }
2323 best_row = png_ptr->avg_row;
2324 }
2325
2326 else if (filter_to_do & PNG_FILTER_AVG)
2327 {
2328 png_bytep rp, dp, pp, lp;
2329 png_uint_32 sum = 0, lmins = mins;
2330 png_uint_32 i;
2331 int v;
2332
2333 for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
2334 pp = prev_row + 1; i < bpp; i++)
2335 {
2336 v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
2337
2338 sum += (v < 128) ? v : 256 - v;
2339 }
2340 for (lp = row_buf + 1; i < row_bytes; i++)
2341 {
2342 v = *dp++ =
2343 (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) & 0xff);
2344
2345 sum += (v < 128) ? v : 256 - v;
2346
2347 if (sum > lmins) /* We are already worse, don't continue. */
2348 break;
2349 }
2350
2351 if (sum < mins)
2352 {
2353 mins = sum;
2354 best_row = png_ptr->avg_row;
2355 }
2356 }
2357
2358 /* Paeth filter */
2359 if (filter_to_do == PNG_FILTER_PAETH)
2360 {
2361 png_bytep rp, dp, pp, cp, lp;
2362 png_uint_32 i;
2363 for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
2364 pp = prev_row + 1; i < bpp; i++)
2365 {
2366 *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
2367 }
2368
2369 for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
2370 {
2371 int a, b, c, pa, pb, pc, p;
2372
2373 b = *pp++;
2374 c = *cp++;
2375 a = *lp++;
2376
2377 p = b - c;
2378 pc = a - c;
2379
2380#ifdef PNG_USE_ABS
2381 pa = abs(p);
2382 pb = abs(pc);
2383 pc = abs(p + pc);
2384#else
2385 pa = p < 0 ? -p : p;
2386 pb = pc < 0 ? -pc : pc;
2387 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
2388#endif
2389
2390 p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
2391
2392 *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
2393 }
2394 best_row = png_ptr->paeth_row;
2395 }
2396
2397 else if (filter_to_do & PNG_FILTER_PAETH)
2398 {
2399 png_bytep rp, dp, pp, cp, lp;
2400 png_uint_32 sum = 0, lmins = mins;
2401 png_uint_32 i;
2402 int v;
2403
2404 for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
2405 pp = prev_row + 1; i < bpp; i++)
2406 {
2407 v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
2408
2409 sum += (v < 128) ? v : 256 - v;
2410 }
2411
2412 for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
2413 {
2414 int a, b, c, pa, pb, pc, p;
2415
2416 b = *pp++;
2417 c = *cp++;
2418 a = *lp++;
2419
2420#ifndef PNG_SLOW_PAETH
2421 p = b - c;
2422 pc = a - c;
2423#ifdef PNG_USE_ABS
2424 pa = abs(p);
2425 pb = abs(pc);
2426 pc = abs(p + pc);
2427#else
2428 pa = p < 0 ? -p : p;
2429 pb = pc < 0 ? -pc : pc;
2430 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
2431#endif
2432 p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
2433#else /* PNG_SLOW_PAETH */
2434 p = a + b - c;
2435 pa = abs(p - a);
2436 pb = abs(p - b);
2437 pc = abs(p - c);
2438 if (pa <= pb && pa <= pc)
2439 p = a;
2440 else if (pb <= pc)
2441 p = b;
2442 else
2443 p = c;
2444#endif /* PNG_SLOW_PAETH */
2445
2446 v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
2447
2448 sum += (v < 128) ? v : 256 - v;
2449
2450 if (sum > lmins) /* We are already worse, don't continue. */
2451 break;
2452 }
2453
2454 if (sum < mins)
2455 {
2456 best_row = png_ptr->paeth_row;
2457 }
2458 }
2459#endif /* PNG_WRITE_FILTER_SUPPORTED */
2460 /* Do the actual writing of the filtered row data from the chosen filter. */
2461
2462 png_write_filtered_row(png_ptr, best_row);
2463}
2464
2465
2466/* Do the actual writing of a previously filtered row. */
2467void /* PRIVATE */
2468png_write_filtered_row(png_structp png_ptr, png_bytep filtered_row)
2469{
2470 png_debug(1, "in png_write_filtered_row");
2471
2472 png_debug1(2, "filter = %d", filtered_row[0]);
2473 /* Set up the zlib input buffer */
2474
2475 png_ptr->zstream.next_in = filtered_row;
2476 png_ptr->zstream.avail_in = (uInt)png_ptr->row_info.rowbytes + 1;
2477 /* Repeat until we have compressed all the data */
2478 do
2479 {
2480 int ret; /* Return of zlib */
2481
2482 /* Compress the data */
2483 ret = deflate(&png_ptr->zstream, Z_NO_FLUSH);
2484 /* Check for compression errors */
2485 if (ret != Z_OK)
2486 {
2487 if (png_ptr->zstream.msg != NULL)
2488 png_error(png_ptr, png_ptr->zstream.msg);
2489 else
2490 png_error(png_ptr, "zlib error");
2491 }
2492
2493 /* See if it is time to write another IDAT */
2494 if (!(png_ptr->zstream.avail_out))
2495 {
2496 /* Write the IDAT and reset the zlib output buffer */
2497 png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
2498 png_ptr->zstream.next_out = png_ptr->zbuf;
2499 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
2500 }
2501 /* Repeat until all data has been compressed */
2502 } while (png_ptr->zstream.avail_in);
2503
2504 /* Swap the current and previous rows */
2505 if (png_ptr->prev_row != NULL)
2506 {
2507 png_bytep tptr;
2508
2509 tptr = png_ptr->prev_row;
2510 png_ptr->prev_row = png_ptr->row_buf;
2511 png_ptr->row_buf = tptr;
2512 }
2513
2514 /* Finish row - updates counters and flushes zlib if last row */
2515 png_write_finish_row(png_ptr);
2516
2517#ifdef PNG_WRITE_FLUSH_SUPPORTED
2518 png_ptr->flush_rows++;
2519
2520 if (png_ptr->flush_dist > 0 &&
2521 png_ptr->flush_rows >= png_ptr->flush_dist)
2522 {
2523 png_write_flush(png_ptr);
2524 }
2525#endif
2526}
2527#endif /* PNG_WRITE_SUPPORTED */
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