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1
2 /* pngwutil.c - utilities to write a PNG file
3 *
4 * Last changed in libpng 1.2.34 [December 18, 2008]
5 * For conditions of distribution and use, see copyright notice in png.h
6 * Copyright (c) 1998-2008 Glenn Randers-Pehrson
7 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
8 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
9 */
10
11 #define PNG_INTERNAL
12 #include "png.h"
13 #ifdef PNG_WRITE_SUPPORTED
14
15 /* Place a 32-bit number into a buffer in PNG byte order. We work
16 * with unsigned numbers for convenience, although one supported
17 * ancillary chunk uses signed (two's complement) numbers.
18 */
19 void PNGAPI
20 png_save_uint_32(png_bytep buf, png_uint_32 i)
21 {
22 buf[0] = (png_byte)((i >> 24) & 0xff);
23 buf[1] = (png_byte)((i >> 16) & 0xff);
24 buf[2] = (png_byte)((i >> 8) & 0xff);
25 buf[3] = (png_byte)(i & 0xff);
26 }
27
28 /* The png_save_int_32 function assumes integers are stored in two's
29 * complement format. If this isn't the case, then this routine needs to
30 * be modified to write data in two's complement format.
31 */
32 void PNGAPI
33 png_save_int_32(png_bytep buf, png_int_32 i)
34 {
35 buf[0] = (png_byte)((i >> 24) & 0xff);
36 buf[1] = (png_byte)((i >> 16) & 0xff);
37 buf[2] = (png_byte)((i >> 8) & 0xff);
38 buf[3] = (png_byte)(i & 0xff);
39 }
40
41 /* Place a 16-bit number into a buffer in PNG byte order.
42 * The parameter is declared unsigned int, not png_uint_16,
43 * just to avoid potential problems on pre-ANSI C compilers.
44 */
45 void PNGAPI
46 png_save_uint_16(png_bytep buf, unsigned int i)
47 {
48 buf[0] = (png_byte)((i >> 8) & 0xff);
49 buf[1] = (png_byte)(i & 0xff);
50 }
51
52 /* Simple function to write the signature. If we have already written
53 * the magic bytes of the signature, or more likely, the PNG stream is
54 * being embedded into another stream and doesn't need its own signature,
55 * we should call png_set_sig_bytes() to tell libpng how many of the
56 * bytes have already been written.
57 */
58 void /* PRIVATE */
59 png_write_sig(png_structp png_ptr)
60 {
61 png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
62
63 /* write the rest of the 8 byte signature */
64 png_write_data(png_ptr, &png_signature[png_ptr->sig_bytes],
65 (png_size_t)(8 - png_ptr->sig_bytes));
66 if (png_ptr->sig_bytes < 3)
67 png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
68 }
69
70 /* Write a PNG chunk all at once. The type is an array of ASCII characters
71 * representing the chunk name. The array must be at least 4 bytes in
72 * length, and does not need to be null terminated. To be safe, pass the
73 * pre-defined chunk names here, and if you need a new one, define it
74 * where the others are defined. The length is the length of the data.
75 * All the data must be present. If that is not possible, use the
76 * png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end()
77 * functions instead.
78 */
79 void PNGAPI
80 png_write_chunk(png_structp png_ptr, png_bytep chunk_name,
81 png_bytep data, png_size_t length)
82 {
83 if (png_ptr == NULL) return;
84 png_write_chunk_start(png_ptr, chunk_name, (png_uint_32)length);
85 png_write_chunk_data(png_ptr, data, (png_size_t)length);
86 png_write_chunk_end(png_ptr);
87 }
88
89 /* Write the start of a PNG chunk. The type is the chunk type.
90 * The total_length is the sum of the lengths of all the data you will be
91 * passing in png_write_chunk_data().
92 */
93 void PNGAPI
94 png_write_chunk_start(png_structp png_ptr, png_bytep chunk_name,
95 png_uint_32 length)
96 {
97 png_byte buf[8];
98
99 png_debug2(0, "Writing %s chunk, length = %lu", chunk_name,
100 (unsigned long)length);
101 if (png_ptr == NULL) return;
102
103 /* write the length and the chunk name */
104 png_save_uint_32(buf, length);
105 png_memcpy(buf + 4, chunk_name, 4);
106 png_write_data(png_ptr, buf, (png_size_t)8);
107 /* put the chunk name into png_ptr->chunk_name */
108 png_memcpy(png_ptr->chunk_name, chunk_name, 4);
109 /* reset the crc and run it over the chunk name */
110 png_reset_crc(png_ptr);
111 png_calculate_crc(png_ptr, chunk_name, (png_size_t)4);
112 }
113
114 /* Write the data of a PNG chunk started with png_write_chunk_start().
115 * Note that multiple calls to this function are allowed, and that the
116 * sum of the lengths from these calls *must* add up to the total_length
117 * given to png_write_chunk_start().
118 */
119 void PNGAPI
120 png_write_chunk_data(png_structp png_ptr, png_bytep data, png_size_t length)
121 {
122 /* write the data, and run the CRC over it */
123 if (png_ptr == NULL) return;
124 if (data != NULL && length > 0)
125 {
126 png_write_data(png_ptr, data, length);
127 /* update the CRC after writing the data,
128 * in case that the user I/O routine alters it.
129 */
130 png_calculate_crc(png_ptr, data, length);
131 }
132 }
133
134 /* Finish a chunk started with png_write_chunk_start(). */
135 void PNGAPI
136 png_write_chunk_end(png_structp png_ptr)
137 {
138 png_byte buf[4];
139
140 if (png_ptr == NULL) return;
141
142 /* write the crc in a single operation */
143 png_save_uint_32(buf, png_ptr->crc);
144
145 png_write_data(png_ptr, buf, (png_size_t)4);
146 }
147
148 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_iCCP_SUPPORTED)
149 /*
150 * This pair of functions encapsulates the operation of (a) compressing a
151 * text string, and (b) issuing it later as a series of chunk data writes.
152 * The compression_state structure is shared context for these functions
153 * set up by the caller in order to make the whole mess thread-safe.
154 */
155
156 typedef struct
157 {
158 char *input; /* the uncompressed input data */
159 int input_len; /* its length */
160 int num_output_ptr; /* number of output pointers used */
161 int max_output_ptr; /* size of output_ptr */
162 png_charpp output_ptr; /* array of pointers to output */
163 } compression_state;
164
165 /* compress given text into storage in the png_ptr structure */
166 static int /* PRIVATE */
167 png_text_compress(png_structp png_ptr,
168 png_charp text, png_size_t text_len, int compression,
169 compression_state *comp)
170 {
171 int ret;
172
173 comp->num_output_ptr = 0;
174 comp->max_output_ptr = 0;
175 comp->output_ptr = NULL;
176 comp->input = NULL;
177 comp->input_len = 0;
178
179 /* we may just want to pass the text right through */
180 if (compression == PNG_TEXT_COMPRESSION_NONE)
181 {
182 comp->input = text;
183 comp->input_len = text_len;
184 return((int)text_len);
185 }
186
187 if (compression >= PNG_TEXT_COMPRESSION_LAST)
188 {
189 #if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
190 char msg[50];
191 png_snprintf(msg, 50, "Unknown compression type %d", compression);
192 png_warning(png_ptr, msg);
193 #else
194 png_warning(png_ptr, "Unknown compression type");
195 #endif
196 }
197
198 /* We can't write the chunk until we find out how much data we have,
199 * which means we need to run the compressor first and save the
200 * output. This shouldn't be a problem, as the vast majority of
201 * comments should be reasonable, but we will set up an array of
202 * malloc'd pointers to be sure.
203 *
204 * If we knew the application was well behaved, we could simplify this
205 * greatly by assuming we can always malloc an output buffer large
206 * enough to hold the compressed text ((1001 * text_len / 1000) + 12)
207 * and malloc this directly. The only time this would be a bad idea is
208 * if we can't malloc more than 64K and we have 64K of random input
209 * data, or if the input string is incredibly large (although this
210 * wouldn't cause a failure, just a slowdown due to swapping).
211 */
212
213 /* set up the compression buffers */
214 png_ptr->zstream.avail_in = (uInt)text_len;
215 png_ptr->zstream.next_in = (Bytef *)text;
216 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
217 png_ptr->zstream.next_out = (Bytef *)png_ptr->zbuf;
218
219 /* this is the same compression loop as in png_write_row() */
220 do
221 {
222 /* compress the data */
223 ret = deflate(&png_ptr->zstream, Z_NO_FLUSH);
224 if (ret != Z_OK)
225 {
226 /* error */
227 if (png_ptr->zstream.msg != NULL)
228 png_error(png_ptr, png_ptr->zstream.msg);
229 else
230 png_error(png_ptr, "zlib error");
231 }
232 /* check to see if we need more room */
233 if (!(png_ptr->zstream.avail_out))
234 {
235 /* make sure the output array has room */
236 if (comp->num_output_ptr >= comp->max_output_ptr)
237 {
238 int old_max;
239
240 old_max = comp->max_output_ptr;
241 comp->max_output_ptr = comp->num_output_ptr + 4;
242 if (comp->output_ptr != NULL)
243 {
244 png_charpp old_ptr;
245
246 old_ptr = comp->output_ptr;
247 comp->output_ptr = (png_charpp)png_malloc(png_ptr,
248 (png_uint_32)
249 (comp->max_output_ptr * png_sizeof(png_charpp)));
250 png_memcpy(comp->output_ptr, old_ptr, old_max
251 * png_sizeof(png_charp));
252 png_free(png_ptr, old_ptr);
253 }
254 else
255 comp->output_ptr = (png_charpp)png_malloc(png_ptr,
256 (png_uint_32)
257 (comp->max_output_ptr * png_sizeof(png_charp)));
258 }
259
260 /* save the data */
261 comp->output_ptr[comp->num_output_ptr] =
262 (png_charp)png_malloc(png_ptr,
263 (png_uint_32)png_ptr->zbuf_size);
264 png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf,
265 png_ptr->zbuf_size);
266 comp->num_output_ptr++;
267
268 /* and reset the buffer */
269 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
270 png_ptr->zstream.next_out = png_ptr->zbuf;
271 }
272 /* continue until we don't have any more to compress */
273 } while (png_ptr->zstream.avail_in);
274
275 /* finish the compression */
276 do
277 {
278 /* tell zlib we are finished */
279 ret = deflate(&png_ptr->zstream, Z_FINISH);
280
281 if (ret == Z_OK)
282 {
283 /* check to see if we need more room */
284 if (!(png_ptr->zstream.avail_out))
285 {
286 /* check to make sure our output array has room */
287 if (comp->num_output_ptr >= comp->max_output_ptr)
288 {
289 int old_max;
290
291 old_max = comp->max_output_ptr;
292 comp->max_output_ptr = comp->num_output_ptr + 4;
293 if (comp->output_ptr != NULL)
294 {
295 png_charpp old_ptr;
296
297 old_ptr = comp->output_ptr;
298 /* This could be optimized to realloc() */
299 comp->output_ptr = (png_charpp)png_malloc(png_ptr,
300 (png_uint_32)(comp->max_output_ptr *
301 png_sizeof(png_charp)));
302 png_memcpy(comp->output_ptr, old_ptr,
303 old_max * png_sizeof(png_charp));
304 png_free(png_ptr, old_ptr);
305 }
306 else
307 comp->output_ptr = (png_charpp)png_malloc(png_ptr,
308 (png_uint_32)(comp->max_output_ptr *
309 png_sizeof(png_charp)));
310 }
311
312 /* save off the data */
313 comp->output_ptr[comp->num_output_ptr] =
314 (png_charp)png_malloc(png_ptr,
315 (png_uint_32)png_ptr->zbuf_size);
316 png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf,
317 png_ptr->zbuf_size);
318 comp->num_output_ptr++;
319
320 /* and reset the buffer pointers */
321 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
322 png_ptr->zstream.next_out = png_ptr->zbuf;
323 }
324 }
325 else if (ret != Z_STREAM_END)
326 {
327 /* we got an error */
328 if (png_ptr->zstream.msg != NULL)
329 png_error(png_ptr, png_ptr->zstream.msg);
330 else
331 png_error(png_ptr, "zlib error");
332 }
333 } while (ret != Z_STREAM_END);
334
335 /* text length is number of buffers plus last buffer */
336 text_len = png_ptr->zbuf_size * comp->num_output_ptr;
337 if (png_ptr->zstream.avail_out < png_ptr->zbuf_size)
338 text_len += png_ptr->zbuf_size - (png_size_t)png_ptr->zstream.avail_out;
339
340 return((int)text_len);
341 }
342
343 /* ship the compressed text out via chunk writes */
344 static void /* PRIVATE */
345 png_write_compressed_data_out(png_structp png_ptr, compression_state *comp)
346 {
347 int i;
348
349 /* handle the no-compression case */
350 if (comp->input)
351 {
352 png_write_chunk_data(png_ptr, (png_bytep)comp->input,
353 (png_size_t)comp->input_len);
354 return;
355 }
356
357 /* write saved output buffers, if any */
358 for (i = 0; i < comp->num_output_ptr; i++)
359 {
360 png_write_chunk_data(png_ptr, (png_bytep)comp->output_ptr[i],
361 (png_size_t)png_ptr->zbuf_size);
362 png_free(png_ptr, comp->output_ptr[i]);
363 comp->output_ptr[i]=NULL;
364 }
365 if (comp->max_output_ptr != 0)
366 png_free(png_ptr, comp->output_ptr);
367 comp->output_ptr=NULL;
368 /* write anything left in zbuf */
369 if (png_ptr->zstream.avail_out < (png_uint_32)png_ptr->zbuf_size)
370 png_write_chunk_data(png_ptr, png_ptr->zbuf,
371 (png_size_t)(png_ptr->zbuf_size - png_ptr->zstream.avail_out));
372
373 /* reset zlib for another zTXt/iTXt or image data */
374 deflateReset(&png_ptr->zstream);
375 png_ptr->zstream.data_type = Z_BINARY;
376 }
377 #endif
378
379 /* Write the IHDR chunk, and update the png_struct with the necessary
380 * information. Note that the rest of this code depends upon this
381 * information being correct.
382 */
383 void /* PRIVATE */
384 png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height,
385 int bit_depth, int color_type, int compression_type, int filter_type,
386 int interlace_type)
387 {
388 #ifdef PNG_USE_LOCAL_ARRAYS
389 PNG_IHDR;
390 #endif
391 int ret;
392
393 png_byte buf[13]; /* buffer to store the IHDR info */
394
395 png_debug(1, "in png_write_IHDR");
396 /* Check that we have valid input data from the application info */
397 switch (color_type)
398 {
399 case PNG_COLOR_TYPE_GRAY:
400 switch (bit_depth)
401 {
402 case 1:
403 case 2:
404 case 4:
405 case 8:
406 case 16: png_ptr->channels = 1; break;
407 default: png_error(png_ptr, "Invalid bit depth for grayscale image");
408 }
409 break;
410 case PNG_COLOR_TYPE_RGB:
411 if (bit_depth != 8 && bit_depth != 16)
412 png_error(png_ptr, "Invalid bit depth for RGB image");
413 png_ptr->channels = 3;
414 break;
415 case PNG_COLOR_TYPE_PALETTE:
416 switch (bit_depth)
417 {
418 case 1:
419 case 2:
420 case 4:
421 case 8: png_ptr->channels = 1; break;
422 default: png_error(png_ptr, "Invalid bit depth for paletted image");
423 }
424 break;
425 case PNG_COLOR_TYPE_GRAY_ALPHA:
426 if (bit_depth != 8 && bit_depth != 16)
427 png_error(png_ptr, "Invalid bit depth for grayscale+alpha image");
428 png_ptr->channels = 2;
429 break;
430 case PNG_COLOR_TYPE_RGB_ALPHA:
431 if (bit_depth != 8 && bit_depth != 16)
432 png_error(png_ptr, "Invalid bit depth for RGBA image");
433 png_ptr->channels = 4;
434 break;
435 default:
436 png_error(png_ptr, "Invalid image color type specified");
437 }
438
439 if (compression_type != PNG_COMPRESSION_TYPE_BASE)
440 {
441 png_warning(png_ptr, "Invalid compression type specified");
442 compression_type = PNG_COMPRESSION_TYPE_BASE;
443 }
444
445 /* Write filter_method 64 (intrapixel differencing) only if
446 * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
447 * 2. Libpng did not write a PNG signature (this filter_method is only
448 * used in PNG datastreams that are embedded in MNG datastreams) and
449 * 3. The application called png_permit_mng_features with a mask that
450 * included PNG_FLAG_MNG_FILTER_64 and
451 * 4. The filter_method is 64 and
452 * 5. The color_type is RGB or RGBA
453 */
454 if (
455 #if defined(PNG_MNG_FEATURES_SUPPORTED)
456 !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
457 ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) &&
458 (color_type == PNG_COLOR_TYPE_RGB ||
459 color_type == PNG_COLOR_TYPE_RGB_ALPHA) &&
460 (filter_type == PNG_INTRAPIXEL_DIFFERENCING)) &&
461 #endif
462 filter_type != PNG_FILTER_TYPE_BASE)
463 {
464 png_warning(png_ptr, "Invalid filter type specified");
465 filter_type = PNG_FILTER_TYPE_BASE;
466 }
467
468 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
469 if (interlace_type != PNG_INTERLACE_NONE &&
470 interlace_type != PNG_INTERLACE_ADAM7)
471 {
472 png_warning(png_ptr, "Invalid interlace type specified");
473 interlace_type = PNG_INTERLACE_ADAM7;
474 }
475 #else
476 interlace_type=PNG_INTERLACE_NONE;
477 #endif
478
479 /* save off the relevent information */
480 png_ptr->bit_depth = (png_byte)bit_depth;
481 png_ptr->color_type = (png_byte)color_type;
482 png_ptr->interlaced = (png_byte)interlace_type;
483 #if defined(PNG_MNG_FEATURES_SUPPORTED)
484 png_ptr->filter_type = (png_byte)filter_type;
485 #endif
486 png_ptr->compression_type = (png_byte)compression_type;
487 png_ptr->width = width;
488 png_ptr->height = height;
489
490 png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels);
491 png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, width);
492 /* set the usr info, so any transformations can modify it */
493 png_ptr->usr_width = png_ptr->width;
494 png_ptr->usr_bit_depth = png_ptr->bit_depth;
495 png_ptr->usr_channels = png_ptr->channels;
496
497 /* pack the header information into the buffer */
498 png_save_uint_32(buf, width);
499 png_save_uint_32(buf + 4, height);
500 buf[8] = (png_byte)bit_depth;
501 buf[9] = (png_byte)color_type;
502 buf[10] = (png_byte)compression_type;
503 buf[11] = (png_byte)filter_type;
504 buf[12] = (png_byte)interlace_type;
505
506 /* write the chunk */
507 png_write_chunk(png_ptr, (png_bytep)png_IHDR, buf, (png_size_t)13);
508
509 /* initialize zlib with PNG info */
510 png_ptr->zstream.zalloc = png_zalloc;
511 png_ptr->zstream.zfree = png_zfree;
512 png_ptr->zstream.opaque = (voidpf)png_ptr;
513 if (!(png_ptr->do_filter))
514 {
515 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||
516 png_ptr->bit_depth < 8)
517 png_ptr->do_filter = PNG_FILTER_NONE;
518 else
519 png_ptr->do_filter = PNG_ALL_FILTERS;
520 }
521 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY))
522 {
523 if (png_ptr->do_filter != PNG_FILTER_NONE)
524 png_ptr->zlib_strategy = Z_FILTERED;
525 else
526 png_ptr->zlib_strategy = Z_DEFAULT_STRATEGY;
527 }
528 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_LEVEL))
529 png_ptr->zlib_level = Z_DEFAULT_COMPRESSION;
530 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL))
531 png_ptr->zlib_mem_level = 8;
532 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS))
533 png_ptr->zlib_window_bits = 15;
534 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_METHOD))
535 png_ptr->zlib_method = 8;
536 ret = deflateInit2(&png_ptr->zstream, png_ptr->zlib_level,
537 png_ptr->zlib_method, png_ptr->zlib_window_bits,
538 png_ptr->zlib_mem_level, png_ptr->zlib_strategy);
539 if (ret != Z_OK)
540 {
541 if (ret == Z_VERSION_ERROR) png_error(png_ptr,
542 "zlib failed to initialize compressor -- version error");
543 if (ret == Z_STREAM_ERROR) png_error(png_ptr,
544 "zlib failed to initialize compressor -- stream error");
545 if (ret == Z_MEM_ERROR) png_error(png_ptr,
546 "zlib failed to initialize compressor -- mem error");
547 png_error(png_ptr, "zlib failed to initialize compressor");
548 }
549 png_ptr->zstream.next_out = png_ptr->zbuf;
550 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
551 /* libpng is not interested in zstream.data_type */
552 /* set it to a predefined value, to avoid its evaluation inside zlib */
553 png_ptr->zstream.data_type = Z_BINARY;
554
555 png_ptr->mode = PNG_HAVE_IHDR;
556 }
557
558 /* write the palette. We are careful not to trust png_color to be in the
559 * correct order for PNG, so people can redefine it to any convenient
560 * structure.
561 */
562 void /* PRIVATE */
563 png_write_PLTE(png_structp png_ptr, png_colorp palette, png_uint_32 num_pal)
564 {
565 #ifdef PNG_USE_LOCAL_ARRAYS
566 PNG_PLTE;
567 #endif
568 png_uint_32 i;
569 png_colorp pal_ptr;
570 png_byte buf[3];
571
572 png_debug(1, "in png_write_PLTE");
573 if ((
574 #if defined(PNG_MNG_FEATURES_SUPPORTED)
575 !(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) &&
576 #endif
577 num_pal == 0) || num_pal > 256)
578 {
579 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
580 {
581 png_error(png_ptr, "Invalid number of colors in palette");
582 }
583 else
584 {
585 png_warning(png_ptr, "Invalid number of colors in palette");
586 return;
587 }
588 }
589
590 if (!(png_ptr->color_type&PNG_COLOR_MASK_COLOR))
591 {
592 png_warning(png_ptr,
593 "Ignoring request to write a PLTE chunk in grayscale PNG");
594 return;
595 }
596
597 png_ptr->num_palette = (png_uint_16)num_pal;
598 png_debug1(3, "num_palette = %d", png_ptr->num_palette);
599
600 png_write_chunk_start(png_ptr, (png_bytep)png_PLTE,
601 (png_uint_32)(num_pal * 3));
602 #ifndef PNG_NO_POINTER_INDEXING
603 for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++)
604 {
605 buf[0] = pal_ptr->red;
606 buf[1] = pal_ptr->green;
607 buf[2] = pal_ptr->blue;
608 png_write_chunk_data(png_ptr, buf, (png_size_t)3);
609 }
610 #else
611 /* This is a little slower but some buggy compilers need to do this instead */
612 pal_ptr=palette;
613 for (i = 0; i < num_pal; i++)
614 {
615 buf[0] = pal_ptr[i].red;
616 buf[1] = pal_ptr[i].green;
617 buf[2] = pal_ptr[i].blue;
618 png_write_chunk_data(png_ptr, buf, (png_size_t)3);
619 }
620 #endif
621 png_write_chunk_end(png_ptr);
622 png_ptr->mode |= PNG_HAVE_PLTE;
623 }
624
625 /* write an IDAT chunk */
626 void /* PRIVATE */
627 png_write_IDAT(png_structp png_ptr, png_bytep data, png_size_t length)
628 {
629 #ifdef PNG_USE_LOCAL_ARRAYS
630 PNG_IDAT;
631 #endif
632 png_debug(1, "in png_write_IDAT");
633
634 /* Optimize the CMF field in the zlib stream. */
635 /* This hack of the zlib stream is compliant to the stream specification. */
636 if (!(png_ptr->mode & PNG_HAVE_IDAT) &&
637 png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
638 {
639 unsigned int z_cmf = data[0]; /* zlib compression method and flags */
640 if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70)
641 {
642 /* Avoid memory underflows and multiplication overflows. */
643 /* The conditions below are practically always satisfied;
644 however, they still must be checked. */
645 if (length >= 2 &&
646 png_ptr->height < 16384 && png_ptr->width < 16384)
647 {
648 png_uint_32 uncompressed_idat_size = png_ptr->height *
649 ((png_ptr->width *
650 png_ptr->channels * png_ptr->bit_depth + 15) >> 3);
651 unsigned int z_cinfo = z_cmf >> 4;
652 unsigned int half_z_window_size = 1 << (z_cinfo + 7);
653 while (uncompressed_idat_size <= half_z_window_size &&
654 half_z_window_size >= 256)
655 {
656 z_cinfo--;
657 half_z_window_size >>= 1;
658 }
659 z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4);
660 if (data[0] != (png_byte)z_cmf)
661 {
662 data[0] = (png_byte)z_cmf;
663 data[1] &= 0xe0;
664 data[1] += (png_byte)(0x1f - ((z_cmf << 8) + data[1]) % 0x1f);
665 }
666 }
667 }
668 else
669 png_error(png_ptr,
670 "Invalid zlib compression method or flags in IDAT");
671 }
672
673 png_write_chunk(png_ptr, (png_bytep)png_IDAT, data, length);
674 png_ptr->mode |= PNG_HAVE_IDAT;
675 }
676
677 /* write an IEND chunk */
678 void /* PRIVATE */
679 png_write_IEND(png_structp png_ptr)
680 {
681 #ifdef PNG_USE_LOCAL_ARRAYS
682 PNG_IEND;
683 #endif
684 png_debug(1, "in png_write_IEND");
685 png_write_chunk(png_ptr, (png_bytep)png_IEND, png_bytep_NULL,
686 (png_size_t)0);
687 png_ptr->mode |= PNG_HAVE_IEND;
688 }
689
690 #if defined(PNG_WRITE_gAMA_SUPPORTED)
691 /* write a gAMA chunk */
692 #ifdef PNG_FLOATING_POINT_SUPPORTED
693 void /* PRIVATE */
694 png_write_gAMA(png_structp png_ptr, double file_gamma)
695 {
696 #ifdef PNG_USE_LOCAL_ARRAYS
697 PNG_gAMA;
698 #endif
699 png_uint_32 igamma;
700 png_byte buf[4];
701
702 png_debug(1, "in png_write_gAMA");
703 /* file_gamma is saved in 1/100,000ths */
704 igamma = (png_uint_32)(file_gamma * 100000.0 + 0.5);
705 png_save_uint_32(buf, igamma);
706 png_write_chunk(png_ptr, (png_bytep)png_gAMA, buf, (png_size_t)4);
707 }
708 #endif
709 #ifdef PNG_FIXED_POINT_SUPPORTED
710 void /* PRIVATE */
711 png_write_gAMA_fixed(png_structp png_ptr, png_fixed_point file_gamma)
712 {
713 #ifdef PNG_USE_LOCAL_ARRAYS
714 PNG_gAMA;
715 #endif
716 png_byte buf[4];
717
718 png_debug(1, "in png_write_gAMA");
719 /* file_gamma is saved in 1/100,000ths */
720 png_save_uint_32(buf, (png_uint_32)file_gamma);
721 png_write_chunk(png_ptr, (png_bytep)png_gAMA, buf, (png_size_t)4);
722 }
723 #endif
724 #endif
725
726 #if defined(PNG_WRITE_sRGB_SUPPORTED)
727 /* write a sRGB chunk */
728 void /* PRIVATE */
729 png_write_sRGB(png_structp png_ptr, int srgb_intent)
730 {
731 #ifdef PNG_USE_LOCAL_ARRAYS
732 PNG_sRGB;
733 #endif
734 png_byte buf[1];
735
736 png_debug(1, "in png_write_sRGB");
737 if (srgb_intent >= PNG_sRGB_INTENT_LAST)
738 png_warning(png_ptr,
739 "Invalid sRGB rendering intent specified");
740 buf[0]=(png_byte)srgb_intent;
741 png_write_chunk(png_ptr, (png_bytep)png_sRGB, buf, (png_size_t)1);
742 }
743 #endif
744
745 #if defined(PNG_WRITE_iCCP_SUPPORTED)
746 /* write an iCCP chunk */
747 void /* PRIVATE */
748 png_write_iCCP(png_structp png_ptr, png_charp name, int compression_type,
749 png_charp profile, int profile_len)
750 {
751 #ifdef PNG_USE_LOCAL_ARRAYS
752 PNG_iCCP;
753 #endif
754 png_size_t name_len;
755 png_charp new_name;
756 compression_state comp;
757 int embedded_profile_len = 0;
758
759 png_debug(1, "in png_write_iCCP");
760
761 comp.num_output_ptr = 0;
762 comp.max_output_ptr = 0;
763 comp.output_ptr = NULL;
764 comp.input = NULL;
765 comp.input_len = 0;
766
767 if ((name_len = png_check_keyword(png_ptr, name,
768 &new_name)) == 0)
769 return;
770
771 if (compression_type != PNG_COMPRESSION_TYPE_BASE)
772 png_warning(png_ptr, "Unknown compression type in iCCP chunk");
773
774 if (profile == NULL)
775 profile_len = 0;
776
777 if (profile_len > 3)
778 embedded_profile_len =
779 ((*( (png_bytep)profile ))<<24) |
780 ((*( (png_bytep)profile + 1))<<16) |
781 ((*( (png_bytep)profile + 2))<< 8) |
782 ((*( (png_bytep)profile + 3)) );
783
784 if (profile_len < embedded_profile_len)
785 {
786 png_warning(png_ptr,
787 "Embedded profile length too large in iCCP chunk");
788 return;
789 }
790
791 if (profile_len > embedded_profile_len)
792 {
793 png_warning(png_ptr,
794 "Truncating profile to actual length in iCCP chunk");
795 profile_len = embedded_profile_len;
796 }
797
798 if (profile_len)
799 profile_len = png_text_compress(png_ptr, profile,
800 (png_size_t)profile_len, PNG_COMPRESSION_TYPE_BASE, &comp);
801
802 /* make sure we include the NULL after the name and the compression type */
803 png_write_chunk_start(png_ptr, (png_bytep)png_iCCP,
804 (png_uint_32)(name_len + profile_len + 2));
805 new_name[name_len + 1] = 0x00;
806 png_write_chunk_data(png_ptr, (png_bytep)new_name,
807 (png_size_t)(name_len + 2));
808
809 if (profile_len)
810 png_write_compressed_data_out(png_ptr, &comp);
811
812 png_write_chunk_end(png_ptr);
813 png_free(png_ptr, new_name);
814 }
815 #endif
816
817 #if defined(PNG_WRITE_sPLT_SUPPORTED)
818 /* write a sPLT chunk */
819 void /* PRIVATE */
820 png_write_sPLT(png_structp png_ptr, png_sPLT_tp spalette)
821 {
822 #ifdef PNG_USE_LOCAL_ARRAYS
823 PNG_sPLT;
824 #endif
825 png_size_t name_len;
826 png_charp new_name;
827 png_byte entrybuf[10];
828 int entry_size = (spalette->depth == 8 ? 6 : 10);
829 int palette_size = entry_size * spalette->nentries;
830 png_sPLT_entryp ep;
831 #ifdef PNG_NO_POINTER_INDEXING
832 int i;
833 #endif
834
835 png_debug(1, "in png_write_sPLT");
836 if ((name_len = png_check_keyword(png_ptr,
837 spalette->name, &new_name))==0)
838 return;
839
840 /* make sure we include the NULL after the name */
841 png_write_chunk_start(png_ptr, (png_bytep)png_sPLT,
842 (png_uint_32)(name_len + 2 + palette_size));
843 png_write_chunk_data(png_ptr, (png_bytep)new_name,
844 (png_size_t)(name_len + 1));
845 png_write_chunk_data(png_ptr, (png_bytep)&spalette->depth, (png_size_t)1);
846
847 /* loop through each palette entry, writing appropriately */
848 #ifndef PNG_NO_POINTER_INDEXING
849 for (ep = spalette->entries; ep<spalette->entries + spalette->nentries; ep++)
850 {
851 if (spalette->depth == 8)
852 {
853 entrybuf[0] = (png_byte)ep->red;
854 entrybuf[1] = (png_byte)ep->green;
855 entrybuf[2] = (png_byte)ep->blue;
856 entrybuf[3] = (png_byte)ep->alpha;
857 png_save_uint_16(entrybuf + 4, ep->frequency);
858 }
859 else
860 {
861 png_save_uint_16(entrybuf + 0, ep->red);
862 png_save_uint_16(entrybuf + 2, ep->green);
863 png_save_uint_16(entrybuf + 4, ep->blue);
864 png_save_uint_16(entrybuf + 6, ep->alpha);
865 png_save_uint_16(entrybuf + 8, ep->frequency);
866 }
867 png_write_chunk_data(png_ptr, entrybuf, (png_size_t)entry_size);
868 }
869 #else
870 ep=spalette->entries;
871 for (i=0; i>spalette->nentries; i++)
872 {
873 if (spalette->depth == 8)
874 {
875 entrybuf[0] = (png_byte)ep[i].red;
876 entrybuf[1] = (png_byte)ep[i].green;
877 entrybuf[2] = (png_byte)ep[i].blue;
878 entrybuf[3] = (png_byte)ep[i].alpha;
879 png_save_uint_16(entrybuf + 4, ep[i].frequency);
880 }
881 else
882 {
883 png_save_uint_16(entrybuf + 0, ep[i].red);
884 png_save_uint_16(entrybuf + 2, ep[i].green);
885 png_save_uint_16(entrybuf + 4, ep[i].blue);
886 png_save_uint_16(entrybuf + 6, ep[i].alpha);
887 png_save_uint_16(entrybuf + 8, ep[i].frequency);
888 }
889 png_write_chunk_data(png_ptr, entrybuf, (png_size_t)entry_size);
890 }
891 #endif
892
893 png_write_chunk_end(png_ptr);
894 png_free(png_ptr, new_name);
895 }
896 #endif
897
898 #if defined(PNG_WRITE_sBIT_SUPPORTED)
899 /* write the sBIT chunk */
900 void /* PRIVATE */
901 png_write_sBIT(png_structp png_ptr, png_color_8p sbit, int color_type)
902 {
903 #ifdef PNG_USE_LOCAL_ARRAYS
904 PNG_sBIT;
905 #endif
906 png_byte buf[4];
907 png_size_t size;
908
909 png_debug(1, "in png_write_sBIT");
910 /* make sure we don't depend upon the order of PNG_COLOR_8 */
911 if (color_type & PNG_COLOR_MASK_COLOR)
912 {
913 png_byte maxbits;
914
915 maxbits = (png_byte)(color_type==PNG_COLOR_TYPE_PALETTE ? 8 :
916 png_ptr->usr_bit_depth);
917 if (sbit->red == 0 || sbit->red > maxbits ||
918 sbit->green == 0 || sbit->green > maxbits ||
919 sbit->blue == 0 || sbit->blue > maxbits)
920 {
921 png_warning(png_ptr, "Invalid sBIT depth specified");
922 return;
923 }
924 buf[0] = sbit->red;
925 buf[1] = sbit->green;
926 buf[2] = sbit->blue;
927 size = 3;
928 }
929 else
930 {
931 if (sbit->gray == 0 || sbit->gray > png_ptr->usr_bit_depth)
932 {
933 png_warning(png_ptr, "Invalid sBIT depth specified");
934 return;
935 }
936 buf[0] = sbit->gray;
937 size = 1;
938 }
939
940 if (color_type & PNG_COLOR_MASK_ALPHA)
941 {
942 if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth)
943 {
944 png_warning(png_ptr, "Invalid sBIT depth specified");
945 return;
946 }
947 buf[size++] = sbit->alpha;
948 }
949
950 png_write_chunk(png_ptr, (png_bytep)png_sBIT, buf, size);
951 }
952 #endif
953
954 #if defined(PNG_WRITE_cHRM_SUPPORTED)
955 /* write the cHRM chunk */
956 #ifdef PNG_FLOATING_POINT_SUPPORTED
957 void /* PRIVATE */
958 png_write_cHRM(png_structp png_ptr, double white_x, double white_y,
959 double red_x, double red_y, double green_x, double green_y,
960 double blue_x, double blue_y)
961 {
962 #ifdef PNG_USE_LOCAL_ARRAYS
963 PNG_cHRM;
964 #endif
965 png_byte buf[32];
966
967 png_fixed_point int_white_x, int_white_y, int_red_x, int_red_y,
968 int_green_x, int_green_y, int_blue_x, int_blue_y;
969
970 png_debug(1, "in png_write_cHRM");
971
972 int_white_x = (png_uint_32)(white_x * 100000.0 + 0.5);
973 int_white_y = (png_uint_32)(white_y * 100000.0 + 0.5);
974 int_red_x = (png_uint_32)(red_x * 100000.0 + 0.5);
975 int_red_y = (png_uint_32)(red_y * 100000.0 + 0.5);
976 int_green_x = (png_uint_32)(green_x * 100000.0 + 0.5);
977 int_green_y = (png_uint_32)(green_y * 100000.0 + 0.5);
978 int_blue_x = (png_uint_32)(blue_x * 100000.0 + 0.5);
979 int_blue_y = (png_uint_32)(blue_y * 100000.0 + 0.5);
980
981 #if !defined(PNG_NO_CHECK_cHRM)
982 if (png_check_cHRM_fixed(png_ptr, int_white_x, int_white_y,
983 int_red_x, int_red_y, int_green_x, int_green_y, int_blue_x, int_blue_y))
984 #endif
985 {
986 /* each value is saved in 1/100,000ths */
987
988 png_save_uint_32(buf, int_white_x);
989 png_save_uint_32(buf + 4, int_white_y);
990
991 png_save_uint_32(buf + 8, int_red_x);
992 png_save_uint_32(buf + 12, int_red_y);
993
994 png_save_uint_32(buf + 16, int_green_x);
995 png_save_uint_32(buf + 20, int_green_y);
996
997 png_save_uint_32(buf + 24, int_blue_x);
998 png_save_uint_32(buf + 28, int_blue_y);
999
1000 png_write_chunk(png_ptr, (png_bytep)png_cHRM, buf, (png_size_t)32);
1001 }
1002 }
1003 #endif
1004 #ifdef PNG_FIXED_POINT_SUPPORTED
1005 void /* PRIVATE */
1006 png_write_cHRM_fixed(png_structp png_ptr, png_fixed_point white_x,
1007 png_fixed_point white_y, png_fixed_point red_x, png_fixed_point red_y,
1008 png_fixed_point green_x, png_fixed_point green_y, png_fixed_point blue_x,
1009 png_fixed_point blue_y)
1010 {
1011 #ifdef PNG_USE_LOCAL_ARRAYS
1012 PNG_cHRM;
1013 #endif
1014 png_byte buf[32];
1015
1016 png_debug(1, "in png_write_cHRM");
1017 /* each value is saved in 1/100,000ths */
1018 #if !defined(PNG_NO_CHECK_cHRM)
1019 if (png_check_cHRM_fixed(png_ptr, white_x, white_y, red_x, red_y,
1020 green_x, green_y, blue_x, blue_y))
1021 #endif
1022 {
1023 png_save_uint_32(buf, (png_uint_32)white_x);
1024 png_save_uint_32(buf + 4, (png_uint_32)white_y);
1025
1026 png_save_uint_32(buf + 8, (png_uint_32)red_x);
1027 png_save_uint_32(buf + 12, (png_uint_32)red_y);
1028
1029 png_save_uint_32(buf + 16, (png_uint_32)green_x);
1030 png_save_uint_32(buf + 20, (png_uint_32)green_y);
1031
1032 png_save_uint_32(buf + 24, (png_uint_32)blue_x);
1033 png_save_uint_32(buf + 28, (png_uint_32)blue_y);
1034
1035 png_write_chunk(png_ptr, (png_bytep)png_cHRM, buf, (png_size_t)32);
1036 }
1037 }
1038 #endif
1039 #endif
1040
1041 #if defined(PNG_WRITE_tRNS_SUPPORTED)
1042 /* write the tRNS chunk */
1043 void /* PRIVATE */
1044 png_write_tRNS(png_structp png_ptr, png_bytep trans, png_color_16p tran,
1045 int num_trans, int color_type)
1046 {
1047 #ifdef PNG_USE_LOCAL_ARRAYS
1048 PNG_tRNS;
1049 #endif
1050 png_byte buf[6];
1051
1052 png_debug(1, "in png_write_tRNS");
1053 if (color_type == PNG_COLOR_TYPE_PALETTE)
1054 {
1055 if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette)
1056 {
1057 png_warning(png_ptr, "Invalid number of transparent colors specified");
1058 return;
1059 }
1060 /* write the chunk out as it is */
1061 png_write_chunk(png_ptr, (png_bytep)png_tRNS, trans,
1062 (png_size_t)num_trans);
1063 }
1064 else if (color_type == PNG_COLOR_TYPE_GRAY)
1065 {
1066 /* one 16 bit value */
1067 if (tran->gray >= (1 << png_ptr->bit_depth))
1068 {
1069 png_warning(png_ptr,
1070 "Ignoring attempt to write tRNS chunk out-of-range for bit_depth");
1071 return;
1072 }
1073 png_save_uint_16(buf, tran->gray);
1074 png_write_chunk(png_ptr, (png_bytep)png_tRNS, buf, (png_size_t)2);
1075 }
1076 else if (color_type == PNG_COLOR_TYPE_RGB)
1077 {
1078 /* three 16 bit values */
1079 png_save_uint_16(buf, tran->red);
1080 png_save_uint_16(buf + 2, tran->green);
1081 png_save_uint_16(buf + 4, tran->blue);
1082 if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
1083 {
1084 png_warning(png_ptr,
1085 "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8");
1086 return;
1087 }
1088 png_write_chunk(png_ptr, (png_bytep)png_tRNS, buf, (png_size_t)6);
1089 }
1090 else
1091 {
1092 png_warning(png_ptr, "Can't write tRNS with an alpha channel");
1093 }
1094 }
1095 #endif
1096
1097 #if defined(PNG_WRITE_bKGD_SUPPORTED)
1098 /* write the background chunk */
1099 void /* PRIVATE */
1100 png_write_bKGD(png_structp png_ptr, png_color_16p back, int color_type)
1101 {
1102 #ifdef PNG_USE_LOCAL_ARRAYS
1103 PNG_bKGD;
1104 #endif
1105 png_byte buf[6];
1106
1107 png_debug(1, "in png_write_bKGD");
1108 if (color_type == PNG_COLOR_TYPE_PALETTE)
1109 {
1110 if (
1111 #if defined(PNG_MNG_FEATURES_SUPPORTED)
1112 (png_ptr->num_palette ||
1113 (!(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE))) &&
1114 #endif
1115 back->index >= png_ptr->num_palette)
1116 {
1117 png_warning(png_ptr, "Invalid background palette index");
1118 return;
1119 }
1120 buf[0] = back->index;
1121 png_write_chunk(png_ptr, (png_bytep)png_bKGD, buf, (png_size_t)1);
1122 }
1123 else if (color_type & PNG_COLOR_MASK_COLOR)
1124 {
1125 png_save_uint_16(buf, back->red);
1126 png_save_uint_16(buf + 2, back->green);
1127 png_save_uint_16(buf + 4, back->blue);
1128 if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
1129 {
1130 png_warning(png_ptr,
1131 "Ignoring attempt to write 16-bit bKGD chunk when bit_depth is 8");
1132 return;
1133 }
1134 png_write_chunk(png_ptr, (png_bytep)png_bKGD, buf, (png_size_t)6);
1135 }
1136 else
1137 {
1138 if (back->gray >= (1 << png_ptr->bit_depth))
1139 {
1140 png_warning(png_ptr,
1141 "Ignoring attempt to write bKGD chunk out-of-range for bit_depth");
1142 return;
1143 }
1144 png_save_uint_16(buf, back->gray);
1145 png_write_chunk(png_ptr, (png_bytep)png_bKGD, buf, (png_size_t)2);
1146 }
1147 }
1148 #endif
1149
1150 #if defined(PNG_WRITE_hIST_SUPPORTED)
1151 /* write the histogram */
1152 void /* PRIVATE */
1153 png_write_hIST(png_structp png_ptr, png_uint_16p hist, int num_hist)
1154 {
1155 #ifdef PNG_USE_LOCAL_ARRAYS
1156 PNG_hIST;
1157 #endif
1158 int i;
1159 png_byte buf[3];
1160
1161 png_debug(1, "in png_write_hIST");
1162 if (num_hist > (int)png_ptr->num_palette)
1163 {
1164 png_debug2(3, "num_hist = %d, num_palette = %d", num_hist,
1165 png_ptr->num_palette);
1166 png_warning(png_ptr, "Invalid number of histogram entries specified");
1167 return;
1168 }
1169
1170 png_write_chunk_start(png_ptr, (png_bytep)png_hIST,
1171 (png_uint_32)(num_hist * 2));
1172 for (i = 0; i < num_hist; i++)
1173 {
1174 png_save_uint_16(buf, hist[i]);
1175 png_write_chunk_data(png_ptr, buf, (png_size_t)2);
1176 }
1177 png_write_chunk_end(png_ptr);
1178 }
1179 #endif
1180
1181 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \
1182 defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
1183 /* Check that the tEXt or zTXt keyword is valid per PNG 1.0 specification,
1184 * and if invalid, correct the keyword rather than discarding the entire
1185 * chunk. The PNG 1.0 specification requires keywords 1-79 characters in
1186 * length, forbids leading or trailing whitespace, multiple internal spaces,
1187 * and the non-break space (0x80) from ISO 8859-1. Returns keyword length.
1188 *
1189 * The new_key is allocated to hold the corrected keyword and must be freed
1190 * by the calling routine. This avoids problems with trying to write to
1191 * static keywords without having to have duplicate copies of the strings.
1192 */
1193 png_size_t /* PRIVATE */
1194 png_check_keyword(png_structp png_ptr, png_charp key, png_charpp new_key)
1195 {
1196 png_size_t key_len;
1197 png_charp kp, dp;
1198 int kflag;
1199 int kwarn=0;
1200
1201 png_debug(1, "in png_check_keyword");
1202 *new_key = NULL;
1203
1204 if (key == NULL || (key_len = png_strlen(key)) == 0)
1205 {
1206 png_warning(png_ptr, "zero length keyword");
1207 return ((png_size_t)0);
1208 }
1209
1210 png_debug1(2, "Keyword to be checked is '%s'", key);
1211
1212 *new_key = (png_charp)png_malloc_warn(png_ptr, (png_uint_32)(key_len + 2));
1213 if (*new_key == NULL)
1214 {
1215 png_warning(png_ptr, "Out of memory while procesing keyword");
1216 return ((png_size_t)0);
1217 }
1218
1219 /* Replace non-printing characters with a blank and print a warning */
1220 for (kp = key, dp = *new_key; *kp != '\0'; kp++, dp++)
1221 {
1222 if ((png_byte)*kp < 0x20 ||
1223 ((png_byte)*kp > 0x7E && (png_byte)*kp < 0xA1))
1224 {
1225 #if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
1226 char msg[40];
1227
1228 png_snprintf(msg, 40,
1229 "invalid keyword character 0x%02X", (png_byte)*kp);
1230 png_warning(png_ptr, msg);
1231 #else
1232 png_warning(png_ptr, "invalid character in keyword");
1233 #endif
1234 *dp = ' ';
1235 }
1236 else
1237 {
1238 *dp = *kp;
1239 }
1240 }
1241 *dp = '\0';
1242
1243 /* Remove any trailing white space. */
1244 kp = *new_key + key_len - 1;
1245 if (*kp == ' ')
1246 {
1247 png_warning(png_ptr, "trailing spaces removed from keyword");
1248
1249 while (*kp == ' ')
1250 {
1251 *(kp--) = '\0';
1252 key_len--;
1253 }
1254 }
1255
1256 /* Remove any leading white space. */
1257 kp = *new_key;
1258 if (*kp == ' ')
1259 {
1260 png_warning(png_ptr, "leading spaces removed from keyword");
1261
1262 while (*kp == ' ')
1263 {
1264 kp++;
1265 key_len--;
1266 }
1267 }
1268
1269 png_debug1(2, "Checking for multiple internal spaces in '%s'", kp);
1270
1271 /* Remove multiple internal spaces. */
1272 for (kflag = 0, dp = *new_key; *kp != '\0'; kp++)
1273 {
1274 if (*kp == ' ' && kflag == 0)
1275 {
1276 *(dp++) = *kp;
1277 kflag = 1;
1278 }
1279 else if (*kp == ' ')
1280 {
1281 key_len--;
1282 kwarn=1;
1283 }
1284 else
1285 {
1286 *(dp++) = *kp;
1287 kflag = 0;
1288 }
1289 }
1290 *dp = '\0';
1291 if (kwarn)
1292 png_warning(png_ptr, "extra interior spaces removed from keyword");
1293
1294 if (key_len == 0)
1295 {
1296 png_free(png_ptr, *new_key);
1297 *new_key=NULL;
1298 png_warning(png_ptr, "Zero length keyword");
1299 }
1300
1301 if (key_len > 79)
1302 {
1303 png_warning(png_ptr, "keyword length must be 1 - 79 characters");
1304 (*new_key)[79] = '\0';
1305 key_len = 79;
1306 }
1307
1308 return (key_len);
1309 }
1310 #endif
1311
1312 #if defined(PNG_WRITE_tEXt_SUPPORTED)
1313 /* write a tEXt chunk */
1314 void /* PRIVATE */
1315 png_write_tEXt(png_structp png_ptr, png_charp key, png_charp text,
1316 png_size_t text_len)
1317 {
1318 #ifdef PNG_USE_LOCAL_ARRAYS
1319 PNG_tEXt;
1320 #endif
1321 png_size_t key_len;
1322 png_charp new_key;
1323
1324 png_debug(1, "in png_write_tEXt");
1325 if ((key_len = png_check_keyword(png_ptr, key, &new_key))==0)
1326 return;
1327
1328 if (text == NULL || *text == '\0')
1329 text_len = 0;
1330 else
1331 text_len = png_strlen(text);
1332
1333 /* make sure we include the 0 after the key */
1334 png_write_chunk_start(png_ptr, (png_bytep)png_tEXt,
1335 (png_uint_32)(key_len + text_len + 1));
1336 /*
1337 * We leave it to the application to meet PNG-1.0 requirements on the
1338 * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of
1339 * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them.
1340 * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
1341 */
1342 png_write_chunk_data(png_ptr, (png_bytep)new_key,
1343 (png_size_t)(key_len + 1));
1344 if (text_len)
1345 png_write_chunk_data(png_ptr, (png_bytep)text, (png_size_t)text_len);
1346
1347 png_write_chunk_end(png_ptr);
1348 png_free(png_ptr, new_key);
1349 }
1350 #endif
1351
1352 #if defined(PNG_WRITE_zTXt_SUPPORTED)
1353 /* write a compressed text chunk */
1354 void /* PRIVATE */
1355 png_write_zTXt(png_structp png_ptr, png_charp key, png_charp text,
1356 png_size_t text_len, int compression)
1357 {
1358 #ifdef PNG_USE_LOCAL_ARRAYS
1359 PNG_zTXt;
1360 #endif
1361 png_size_t key_len;
1362 char buf[1];
1363 png_charp new_key;
1364 compression_state comp;
1365
1366 png_debug(1, "in png_write_zTXt");
1367
1368 comp.num_output_ptr = 0;
1369 comp.max_output_ptr = 0;
1370 comp.output_ptr = NULL;
1371 comp.input = NULL;
1372 comp.input_len = 0;
1373
1374 if ((key_len = png_check_keyword(png_ptr, key, &new_key))==0)
1375 {
1376 png_free(png_ptr, new_key);
1377 return;
1378 }
1379
1380 if (text == NULL || *text == '\0' || compression==PNG_TEXT_COMPRESSION_NONE)
1381 {
1382 png_write_tEXt(png_ptr, new_key, text, (png_size_t)0);
1383 png_free(png_ptr, new_key);
1384 return;
1385 }
1386
1387 text_len = png_strlen(text);
1388
1389 /* compute the compressed data; do it now for the length */
1390 text_len = png_text_compress(png_ptr, text, text_len, compression,
1391 &comp);
1392
1393 /* write start of chunk */
1394 png_write_chunk_start(png_ptr, (png_bytep)png_zTXt,
1395 (png_uint_32)(key_len+text_len + 2));
1396 /* write key */
1397 png_write_chunk_data(png_ptr, (png_bytep)new_key,
1398 (png_size_t)(key_len + 1));
1399 png_free(png_ptr, new_key);
1400
1401 buf[0] = (png_byte)compression;
1402 /* write compression */
1403 png_write_chunk_data(png_ptr, (png_bytep)buf, (png_size_t)1);
1404 /* write the compressed data */
1405 png_write_compressed_data_out(png_ptr, &comp);
1406
1407 /* close the chunk */
1408 png_write_chunk_end(png_ptr);
1409 }
1410 #endif
1411
1412 #if defined(PNG_WRITE_iTXt_SUPPORTED)
1413 /* write an iTXt chunk */
1414 void /* PRIVATE */
1415 png_write_iTXt(png_structp png_ptr, int compression, png_charp key,
1416 png_charp lang, png_charp lang_key, png_charp text)
1417 {
1418 #ifdef PNG_USE_LOCAL_ARRAYS
1419 PNG_iTXt;
1420 #endif
1421 png_size_t lang_len, key_len, lang_key_len, text_len;
1422 png_charp new_lang;
1423 png_charp new_key = NULL;
1424 png_byte cbuf[2];
1425 compression_state comp;
1426
1427 png_debug(1, "in png_write_iTXt");
1428
1429 comp.num_output_ptr = 0;
1430 comp.max_output_ptr = 0;
1431 comp.output_ptr = NULL;
1432 comp.input = NULL;
1433
1434 if ((key_len = png_check_keyword(png_ptr, key, &new_key))==0)
1435 return;
1436
1437 if ((lang_len = png_check_keyword(png_ptr, lang, &new_lang))==0)
1438 {
1439 png_warning(png_ptr, "Empty language field in iTXt chunk");
1440 new_lang = NULL;
1441 lang_len = 0;
1442 }
1443
1444 if (lang_key == NULL)
1445 lang_key_len = 0;
1446 else
1447 lang_key_len = png_strlen(lang_key);
1448
1449 if (text == NULL)
1450 text_len = 0;
1451 else
1452 text_len = png_strlen(text);
1453
1454 /* compute the compressed data; do it now for the length */
1455 text_len = png_text_compress(png_ptr, text, text_len, compression-2,
1456 &comp);
1457
1458
1459 /* make sure we include the compression flag, the compression byte,
1460 * and the NULs after the key, lang, and lang_key parts */
1461
1462 png_write_chunk_start(png_ptr, (png_bytep)png_iTXt,
1463 (png_uint_32)(
1464 5 /* comp byte, comp flag, terminators for key, lang and lang_key */
1465 + key_len
1466 + lang_len
1467 + lang_key_len
1468 + text_len));
1469
1470 /*
1471 * We leave it to the application to meet PNG-1.0 requirements on the
1472 * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of
1473 * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them.
1474 * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
1475 */
1476 png_write_chunk_data(png_ptr, (png_bytep)new_key,
1477 (png_size_t)(key_len + 1));
1478
1479 /* set the compression flag */
1480 if (compression == PNG_ITXT_COMPRESSION_NONE || \
1481 compression == PNG_TEXT_COMPRESSION_NONE)
1482 cbuf[0] = 0;
1483 else /* compression == PNG_ITXT_COMPRESSION_zTXt */
1484 cbuf[0] = 1;
1485 /* set the compression method */
1486 cbuf[1] = 0;
1487 png_write_chunk_data(png_ptr, cbuf, (png_size_t)2);
1488
1489 cbuf[0] = 0;
1490 png_write_chunk_data(png_ptr, (new_lang ? (png_bytep)new_lang : cbuf),
1491 (png_size_t)(lang_len + 1));
1492 png_write_chunk_data(png_ptr, (lang_key ? (png_bytep)lang_key : cbuf),
1493 (png_size_t)(lang_key_len + 1));
1494 png_write_compressed_data_out(png_ptr, &comp);
1495
1496 png_write_chunk_end(png_ptr);
1497 png_free(png_ptr, new_key);
1498 png_free(png_ptr, new_lang);
1499 }
1500 #endif
1501
1502 #if defined(PNG_WRITE_oFFs_SUPPORTED)
1503 /* write the oFFs chunk */
1504 void /* PRIVATE */
1505 png_write_oFFs(png_structp png_ptr, png_int_32 x_offset, png_int_32 y_offset,
1506 int unit_type)
1507 {
1508 #ifdef PNG_USE_LOCAL_ARRAYS
1509 PNG_oFFs;
1510 #endif
1511 png_byte buf[9];
1512
1513 png_debug(1, "in png_write_oFFs");
1514 if (unit_type >= PNG_OFFSET_LAST)
1515 png_warning(png_ptr, "Unrecognized unit type for oFFs chunk");
1516
1517 png_save_int_32(buf, x_offset);
1518 png_save_int_32(buf + 4, y_offset);
1519 buf[8] = (png_byte)unit_type;
1520
1521 png_write_chunk(png_ptr, (png_bytep)png_oFFs, buf, (png_size_t)9);
1522 }
1523 #endif
1524 #if defined(PNG_WRITE_pCAL_SUPPORTED)
1525 /* write the pCAL chunk (described in the PNG extensions document) */
1526 void /* PRIVATE */
1527 png_write_pCAL(png_structp png_ptr, png_charp purpose, png_int_32 X0,
1528 png_int_32 X1, int type, int nparams, png_charp units, png_charpp params)
1529 {
1530 #ifdef PNG_USE_LOCAL_ARRAYS
1531 PNG_pCAL;
1532 #endif
1533 png_size_t purpose_len, units_len, total_len;
1534 png_uint_32p params_len;
1535 png_byte buf[10];
1536 png_charp new_purpose;
1537 int i;
1538
1539 png_debug1(1, "in png_write_pCAL (%d parameters)", nparams);
1540 if (type >= PNG_EQUATION_LAST)
1541 png_warning(png_ptr, "Unrecognized equation type for pCAL chunk");
1542
1543 purpose_len = png_check_keyword(png_ptr, purpose, &new_purpose) + 1;
1544 png_debug1(3, "pCAL purpose length = %d", (int)purpose_len);
1545 units_len = png_strlen(units) + (nparams == 0 ? 0 : 1);
1546 png_debug1(3, "pCAL units length = %d", (int)units_len);
1547 total_len = purpose_len + units_len + 10;
1548
1549 params_len = (png_uint_32p)png_malloc(png_ptr,
1550 (png_uint_32)(nparams * png_sizeof(png_uint_32)));
1551
1552 /* Find the length of each parameter, making sure we don't count the
1553 null terminator for the last parameter. */
1554 for (i = 0; i < nparams; i++)
1555 {
1556 params_len[i] = png_strlen(params[i]) + (i == nparams - 1 ? 0 : 1);
1557 png_debug2(3, "pCAL parameter %d length = %lu", i,
1558 (unsigned long) params_len[i]);
1559 total_len += (png_size_t)params_len[i];
1560 }
1561
1562 png_debug1(3, "pCAL total length = %d", (int)total_len);
1563 png_write_chunk_start(png_ptr, (png_bytep)png_pCAL, (png_uint_32)total_len);
1564 png_write_chunk_data(png_ptr, (png_bytep)new_purpose,
1565 (png_size_t)purpose_len);
1566 png_save_int_32(buf, X0);
1567 png_save_int_32(buf + 4, X1);
1568 buf[8] = (png_byte)type;
1569 buf[9] = (png_byte)nparams;
1570 png_write_chunk_data(png_ptr, buf, (png_size_t)10);
1571 png_write_chunk_data(png_ptr, (png_bytep)units, (png_size_t)units_len);
1572
1573 png_free(png_ptr, new_purpose);
1574
1575 for (i = 0; i < nparams; i++)
1576 {
1577 png_write_chunk_data(png_ptr, (png_bytep)params[i],
1578 (png_size_t)params_len[i]);
1579 }
1580
1581 png_free(png_ptr, params_len);
1582 png_write_chunk_end(png_ptr);
1583 }
1584 #endif
1585
1586 #if defined(PNG_WRITE_sCAL_SUPPORTED)
1587 /* write the sCAL chunk */
1588 #if defined(PNG_FLOATING_POINT_SUPPORTED) && !defined(PNG_NO_STDIO)
1589 void /* PRIVATE */
1590 png_write_sCAL(png_structp png_ptr, int unit, double width, double height)
1591 {
1592 #ifdef PNG_USE_LOCAL_ARRAYS
1593 PNG_sCAL;
1594 #endif
1595 char buf[64];
1596 png_size_t total_len;
1597
1598 png_debug(1, "in png_write_sCAL");
1599
1600 buf[0] = (char)unit;
1601 #if defined(_WIN32_WCE)
1602 /* sprintf() function is not supported on WindowsCE */
1603 {
1604 wchar_t wc_buf[32];
1605 size_t wc_len;
1606 swprintf(wc_buf, TEXT("%12.12e"), width);
1607 wc_len = wcslen(wc_buf);
1608 WideCharToMultiByte(CP_ACP, 0, wc_buf, -1, buf + 1, wc_len, NULL, NULL);
1609 total_len = wc_len + 2;
1610 swprintf(wc_buf, TEXT("%12.12e"), height);
1611 wc_len = wcslen(wc_buf);
1612 WideCharToMultiByte(CP_ACP, 0, wc_buf, -1, buf + total_len, wc_len,
1613 NULL, NULL);
1614 total_len += wc_len;
1615 }
1616 #else
1617 png_snprintf(buf + 1, 63, "%12.12e", width);
1618 total_len = 1 + png_strlen(buf + 1) + 1;
1619 png_snprintf(buf + total_len, 64-total_len, "%12.12e", height);
1620 total_len += png_strlen(buf + total_len);
1621 #endif
1622
1623 png_debug1(3, "sCAL total length = %u", (unsigned int)total_len);
1624 png_write_chunk(png_ptr, (png_bytep)png_sCAL, (png_bytep)buf, total_len);
1625 }
1626 #else
1627 #ifdef PNG_FIXED_POINT_SUPPORTED
1628 void /* PRIVATE */
1629 png_write_sCAL_s(png_structp png_ptr, int unit, png_charp width,
1630 png_charp height)
1631 {
1632 #ifdef PNG_USE_LOCAL_ARRAYS
1633 PNG_sCAL;
1634 #endif
1635 png_byte buf[64];
1636 png_size_t wlen, hlen, total_len;
1637
1638 png_debug(1, "in png_write_sCAL_s");
1639
1640 wlen = png_strlen(width);
1641 hlen = png_strlen(height);
1642 total_len = wlen + hlen + 2;
1643 if (total_len > 64)
1644 {
1645 png_warning(png_ptr, "Can't write sCAL (buffer too small)");
1646 return;
1647 }
1648
1649 buf[0] = (png_byte)unit;
1650 png_memcpy(buf + 1, width, wlen + 1); /* append the '\0' here */
1651 png_memcpy(buf + wlen + 2, height, hlen); /* do NOT append the '\0' here */
1652
1653 png_debug1(3, "sCAL total length = %u", (unsigned int)total_len);
1654 png_write_chunk(png_ptr, (png_bytep)png_sCAL, buf, total_len);
1655 }
1656 #endif
1657 #endif
1658 #endif
1659
1660 #if defined(PNG_WRITE_pHYs_SUPPORTED)
1661 /* write the pHYs chunk */
1662 void /* PRIVATE */
1663 png_write_pHYs(png_structp png_ptr, png_uint_32 x_pixels_per_unit,
1664 png_uint_32 y_pixels_per_unit,
1665 int unit_type)
1666 {
1667 #ifdef PNG_USE_LOCAL_ARRAYS
1668 PNG_pHYs;
1669 #endif
1670 png_byte buf[9];
1671
1672 png_debug(1, "in png_write_pHYs");
1673 if (unit_type >= PNG_RESOLUTION_LAST)
1674 png_warning(png_ptr, "Unrecognized unit type for pHYs chunk");
1675
1676 png_save_uint_32(buf, x_pixels_per_unit);
1677 png_save_uint_32(buf + 4, y_pixels_per_unit);
1678 buf[8] = (png_byte)unit_type;
1679
1680 png_write_chunk(png_ptr, (png_bytep)png_pHYs, buf, (png_size_t)9);
1681 }
1682 #endif
1683
1684 #if defined(PNG_WRITE_tIME_SUPPORTED)
1685 /* Write the tIME chunk. Use either png_convert_from_struct_tm()
1686 * or png_convert_from_time_t(), or fill in the structure yourself.
1687 */
1688 void /* PRIVATE */
1689 png_write_tIME(png_structp png_ptr, png_timep mod_time)
1690 {
1691 #ifdef PNG_USE_LOCAL_ARRAYS
1692 PNG_tIME;
1693 #endif
1694 png_byte buf[7];
1695
1696 png_debug(1, "in png_write_tIME");
1697 if (mod_time->month > 12 || mod_time->month < 1 ||
1698 mod_time->day > 31 || mod_time->day < 1 ||
1699 mod_time->hour > 23 || mod_time->second > 60)
1700 {
1701 png_warning(png_ptr, "Invalid time specified for tIME chunk");
1702 return;
1703 }
1704
1705 png_save_uint_16(buf, mod_time->year);
1706 buf[2] = mod_time->month;
1707 buf[3] = mod_time->day;
1708 buf[4] = mod_time->hour;
1709 buf[5] = mod_time->minute;
1710 buf[6] = mod_time->second;
1711
1712 png_write_chunk(png_ptr, (png_bytep)png_tIME, buf, (png_size_t)7);
1713 }
1714 #endif
1715
1716 /* initializes the row writing capability of libpng */
1717 void /* PRIVATE */
1718 png_write_start_row(png_structp png_ptr)
1719 {
1720 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1721 #ifdef PNG_USE_LOCAL_ARRAYS
1722 /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
1723
1724 /* start of interlace block */
1725 int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
1726
1727 /* offset to next interlace block */
1728 int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
1729
1730 /* start of interlace block in the y direction */
1731 int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
1732
1733 /* offset to next interlace block in the y direction */
1734 int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
1735 #endif
1736 #endif
1737
1738 png_size_t buf_size;
1739
1740 png_debug(1, "in png_write_start_row");
1741 buf_size = (png_size_t)(PNG_ROWBYTES(
1742 png_ptr->usr_channels*png_ptr->usr_bit_depth, png_ptr->width) + 1);
1743
1744 /* set up row buffer */
1745 png_ptr->row_buf = (png_bytep)png_malloc(png_ptr,
1746 (png_uint_32)buf_size);
1747 png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE;
1748
1749 #ifndef PNG_NO_WRITE_FILTER
1750 /* set up filtering buffer, if using this filter */
1751 if (png_ptr->do_filter & PNG_FILTER_SUB)
1752 {
1753 png_ptr->sub_row = (png_bytep)png_malloc(png_ptr,
1754 (png_uint_32)(png_ptr->rowbytes + 1));
1755 png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
1756 }
1757
1758 /* We only need to keep the previous row if we are using one of these. */
1759 if (png_ptr->do_filter & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH))
1760 {
1761 /* set up previous row buffer */
1762 png_ptr->prev_row = (png_bytep)png_malloc(png_ptr,
1763 (png_uint_32)buf_size);
1764 png_memset(png_ptr->prev_row, 0, buf_size);
1765
1766 if (png_ptr->do_filter & PNG_FILTER_UP)
1767 {
1768 png_ptr->up_row = (png_bytep)png_malloc(png_ptr,
1769 (png_uint_32)(png_ptr->rowbytes + 1));
1770 png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
1771 }
1772
1773 if (png_ptr->do_filter & PNG_FILTER_AVG)
1774 {
1775 png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
1776 (png_uint_32)(png_ptr->rowbytes + 1));
1777 png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
1778 }
1779
1780 if (png_ptr->do_filter & PNG_FILTER_PAETH)
1781 {
1782 png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,
1783 (png_uint_32)(png_ptr->rowbytes + 1));
1784 png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
1785 }
1786 }
1787 #endif /* PNG_NO_WRITE_FILTER */
1788
1789 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1790 /* if interlaced, we need to set up width and height of pass */
1791 if (png_ptr->interlaced)
1792 {
1793 if (!(png_ptr->transformations & PNG_INTERLACE))
1794 {
1795 png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
1796 png_pass_ystart[0]) / png_pass_yinc[0];
1797 png_ptr->usr_width = (png_ptr->width + png_pass_inc[0] - 1 -
1798 png_pass_start[0]) / png_pass_inc[0];
1799 }
1800 else
1801 {
1802 png_ptr->num_rows = png_ptr->height;
1803 png_ptr->usr_width = png_ptr->width;
1804 }
1805 }
1806 else
1807 #endif
1808 {
1809 png_ptr->num_rows = png_ptr->height;
1810 png_ptr->usr_width = png_ptr->width;
1811 }
1812 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1813 png_ptr->zstream.next_out = png_ptr->zbuf;
1814 }
1815
1816 /* Internal use only. Called when finished processing a row of data. */
1817 void /* PRIVATE */
1818 png_write_finish_row(png_structp png_ptr)
1819 {
1820 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1821 #ifdef PNG_USE_LOCAL_ARRAYS
1822 /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
1823
1824 /* start of interlace block */
1825 int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
1826
1827 /* offset to next interlace block */
1828 int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
1829
1830 /* start of interlace block in the y direction */
1831 int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
1832
1833 /* offset to next interlace block in the y direction */
1834 int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
1835 #endif
1836 #endif
1837
1838 int ret;
1839
1840 png_debug(1, "in png_write_finish_row");
1841 /* next row */
1842 png_ptr->row_number++;
1843
1844 /* see if we are done */
1845 if (png_ptr->row_number < png_ptr->num_rows)
1846 return;
1847
1848 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1849 /* if interlaced, go to next pass */
1850 if (png_ptr->interlaced)
1851 {
1852 png_ptr->row_number = 0;
1853 if (png_ptr->transformations & PNG_INTERLACE)
1854 {
1855 png_ptr->pass++;
1856 }
1857 else
1858 {
1859 /* loop until we find a non-zero width or height pass */
1860 do
1861 {
1862 png_ptr->pass++;
1863 if (png_ptr->pass >= 7)
1864 break;
1865 png_ptr->usr_width = (png_ptr->width +
1866 png_pass_inc[png_ptr->pass] - 1 -
1867 png_pass_start[png_ptr->pass]) /
1868 png_pass_inc[png_ptr->pass];
1869 png_ptr->num_rows = (png_ptr->height +
1870 png_pass_yinc[png_ptr->pass] - 1 -
1871 png_pass_ystart[png_ptr->pass]) /
1872 png_pass_yinc[png_ptr->pass];
1873 if (png_ptr->transformations & PNG_INTERLACE)
1874 break;
1875 } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0);
1876
1877 }
1878
1879 /* reset the row above the image for the next pass */
1880 if (png_ptr->pass < 7)
1881 {
1882 if (png_ptr->prev_row != NULL)
1883 png_memset(png_ptr->prev_row, 0,
1884 (png_size_t)(PNG_ROWBYTES(png_ptr->usr_channels*
1885 png_ptr->usr_bit_depth, png_ptr->width)) + 1);
1886 return;
1887 }
1888 }
1889 #endif
1890
1891 /* if we get here, we've just written the last row, so we need
1892 to flush the compressor */
1893 do
1894 {
1895 /* tell the compressor we are done */
1896 ret = deflate(&png_ptr->zstream, Z_FINISH);
1897 /* check for an error */
1898 if (ret == Z_OK)
1899 {
1900 /* check to see if we need more room */
1901 if (!(png_ptr->zstream.avail_out))
1902 {
1903 png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
1904 png_ptr->zstream.next_out = png_ptr->zbuf;
1905 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1906 }
1907 }
1908 else if (ret != Z_STREAM_END)
1909 {
1910 if (png_ptr->zstream.msg != NULL)
1911 png_error(png_ptr, png_ptr->zstream.msg);
1912 else
1913 png_error(png_ptr, "zlib error");
1914 }
1915 } while (ret != Z_STREAM_END);
1916
1917 /* write any extra space */
1918 if (png_ptr->zstream.avail_out < png_ptr->zbuf_size)
1919 {
1920 png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size -
1921 png_ptr->zstream.avail_out);
1922 }
1923
1924 deflateReset(&png_ptr->zstream);
1925 png_ptr->zstream.data_type = Z_BINARY;
1926 }
1927
1928 #if defined(PNG_WRITE_INTERLACING_SUPPORTED)
1929 /* Pick out the correct pixels for the interlace pass.
1930 * The basic idea here is to go through the row with a source
1931 * pointer and a destination pointer (sp and dp), and copy the
1932 * correct pixels for the pass. As the row gets compacted,
1933 * sp will always be >= dp, so we should never overwrite anything.
1934 * See the default: case for the easiest code to understand.
1935 */
1936 void /* PRIVATE */
1937 png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
1938 {
1939 #ifdef PNG_USE_LOCAL_ARRAYS
1940 /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
1941
1942 /* start of interlace block */
1943 int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
1944
1945 /* offset to next interlace block */
1946 int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
1947 #endif
1948
1949 png_debug(1, "in png_do_write_interlace");
1950 /* we don't have to do anything on the last pass (6) */
1951 #if defined(PNG_USELESS_TESTS_SUPPORTED)
1952 if (row != NULL && row_info != NULL && pass < 6)
1953 #else
1954 if (pass < 6)
1955 #endif
1956 {
1957 /* each pixel depth is handled separately */
1958 switch (row_info->pixel_depth)
1959 {
1960 case 1:
1961 {
1962 png_bytep sp;
1963 png_bytep dp;
1964 int shift;
1965 int d;
1966 int value;
1967 png_uint_32 i;
1968 png_uint_32 row_width = row_info->width;
1969
1970 dp = row;
1971 d = 0;
1972 shift = 7;
1973 for (i = png_pass_start[pass]; i < row_width;
1974 i += png_pass_inc[pass])
1975 {
1976 sp = row + (png_size_t)(i >> 3);
1977 value = (int)(*sp >> (7 - (int)(i & 0x07))) & 0x01;
1978 d |= (value << shift);
1979
1980 if (shift == 0)
1981 {
1982 shift = 7;
1983 *dp++ = (png_byte)d;
1984 d = 0;
1985 }
1986 else
1987 shift--;
1988
1989 }
1990 if (shift != 7)
1991 *dp = (png_byte)d;
1992 break;
1993 }
1994 case 2:
1995 {
1996 png_bytep sp;
1997 png_bytep dp;
1998 int shift;
1999 int d;
2000 int value;
2001 png_uint_32 i;
2002 png_uint_32 row_width = row_info->width;
2003
2004 dp = row;
2005 shift = 6;
2006 d = 0;
2007 for (i = png_pass_start[pass]; i < row_width;
2008 i += png_pass_inc[pass])
2009 {
2010 sp = row + (png_size_t)(i >> 2);
2011 value = (*sp >> ((3 - (int)(i & 0x03)) << 1)) & 0x03;
2012 d |= (value << shift);
2013
2014 if (shift == 0)
2015 {
2016 shift = 6;
2017 *dp++ = (png_byte)d;
2018 d = 0;
2019 }
2020 else
2021 shift -= 2;
2022 }
2023 if (shift != 6)
2024 *dp = (png_byte)d;
2025 break;
2026 }
2027 case 4:
2028 {
2029 png_bytep sp;
2030 png_bytep dp;
2031 int shift;
2032 int d;
2033 int value;
2034 png_uint_32 i;
2035 png_uint_32 row_width = row_info->width;
2036
2037 dp = row;
2038 shift = 4;
2039 d = 0;
2040 for (i = png_pass_start[pass]; i < row_width;
2041 i += png_pass_inc[pass])
2042 {
2043 sp = row + (png_size_t)(i >> 1);
2044 value = (*sp >> ((1 - (int)(i & 0x01)) << 2)) & 0x0f;
2045 d |= (value << shift);
2046
2047 if (shift == 0)
2048 {
2049 shift = 4;
2050 *dp++ = (png_byte)d;
2051 d = 0;
2052 }
2053 else
2054 shift -= 4;
2055 }
2056 if (shift != 4)
2057 *dp = (png_byte)d;
2058 break;
2059 }
2060 default:
2061 {
2062 png_bytep sp;
2063 png_bytep dp;
2064 png_uint_32 i;
2065 png_uint_32 row_width = row_info->width;
2066 png_size_t pixel_bytes;
2067
2068 /* start at the beginning */
2069 dp = row;
2070 /* find out how many bytes each pixel takes up */
2071 pixel_bytes = (row_info->pixel_depth >> 3);
2072 /* loop through the row, only looking at the pixels that
2073 matter */
2074 for (i = png_pass_start[pass]; i < row_width;
2075 i += png_pass_inc[pass])
2076 {
2077 /* find out where the original pixel is */
2078 sp = row + (png_size_t)i * pixel_bytes;
2079 /* move the pixel */
2080 if (dp != sp)
2081 png_memcpy(dp, sp, pixel_bytes);
2082 /* next pixel */
2083 dp += pixel_bytes;
2084 }
2085 break;
2086 }
2087 }
2088 /* set new row width */
2089 row_info->width = (row_info->width +
2090 png_pass_inc[pass] - 1 -
2091 png_pass_start[pass]) /
2092 png_pass_inc[pass];
2093 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
2094 row_info->width);
2095 }
2096 }
2097 #endif
2098
2099 /* This filters the row, chooses which filter to use, if it has not already
2100 * been specified by the application, and then writes the row out with the
2101 * chosen filter.
2102 */
2103 #define PNG_MAXSUM (((png_uint_32)(-1)) >> 1)
2104 #define PNG_HISHIFT 10
2105 #define PNG_LOMASK ((png_uint_32)0xffffL)
2106 #define PNG_HIMASK ((png_uint_32)(~PNG_LOMASK >> PNG_HISHIFT))
2107 void /* PRIVATE */
2108 png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
2109 {
2110 png_bytep best_row;
2111 #ifndef PNG_NO_WRITE_FILTER
2112 png_bytep prev_row, row_buf;
2113 png_uint_32 mins, bpp;
2114 png_byte filter_to_do = png_ptr->do_filter;
2115 png_uint_32 row_bytes = row_info->rowbytes;
2116 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2117 int num_p_filters = (int)png_ptr->num_prev_filters;
2118 #endif
2119
2120 png_debug(1, "in png_write_find_filter");
2121 /* find out how many bytes offset each pixel is */
2122 bpp = (row_info->pixel_depth + 7) >> 3;
2123
2124 prev_row = png_ptr->prev_row;
2125 #endif
2126 best_row = png_ptr->row_buf;
2127 #ifndef PNG_NO_WRITE_FILTER
2128 row_buf = best_row;
2129 mins = PNG_MAXSUM;
2130
2131 /* The prediction method we use is to find which method provides the
2132 * smallest value when summing the absolute values of the distances
2133 * from zero, using anything >= 128 as negative numbers. This is known
2134 * as the "minimum sum of absolute differences" heuristic. Other
2135 * heuristics are the "weighted minimum sum of absolute differences"
2136 * (experimental and can in theory improve compression), and the "zlib
2137 * predictive" method (not implemented yet), which does test compressions
2138 * of lines using different filter methods, and then chooses the
2139 * (series of) filter(s) that give minimum compressed data size (VERY
2140 * computationally expensive).
2141 *
2142 * GRR 980525: consider also
2143 * (1) minimum sum of absolute differences from running average (i.e.,
2144 * keep running sum of non-absolute differences & count of bytes)
2145 * [track dispersion, too? restart average if dispersion too large?]
2146 * (1b) minimum sum of absolute differences from sliding average, probably
2147 * with window size <= deflate window (usually 32K)
2148 * (2) minimum sum of squared differences from zero or running average
2149 * (i.e., ~ root-mean-square approach)
2150 */
2151
2152
2153 /* We don't need to test the 'no filter' case if this is the only filter
2154 * that has been chosen, as it doesn't actually do anything to the data.
2155 */
2156 if ((filter_to_do & PNG_FILTER_NONE) &&
2157 filter_to_do != PNG_FILTER_NONE)
2158 {
2159 png_bytep rp;
2160 png_uint_32 sum = 0;
2161 png_uint_32 i;
2162 int v;
2163
2164 for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
2165 {
2166 v = *rp;
2167 sum += (v < 128) ? v : 256 - v;
2168 }
2169
2170 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2171 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2172 {
2173 png_uint_32 sumhi, sumlo;
2174 int j;
2175 sumlo = sum & PNG_LOMASK;
2176 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; /* Gives us some footroom */
2177
2178 /* Reduce the sum if we match any of the previous rows */
2179 for (j = 0; j < num_p_filters; j++)
2180 {
2181 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
2182 {
2183 sumlo = (sumlo * png_ptr->filter_weights[j]) >>
2184 PNG_WEIGHT_SHIFT;
2185 sumhi = (sumhi * png_ptr->filter_weights[j]) >>
2186 PNG_WEIGHT_SHIFT;
2187 }
2188 }
2189
2190 /* Factor in the cost of this filter (this is here for completeness,
2191 * but it makes no sense to have a "cost" for the NONE filter, as
2192 * it has the minimum possible computational cost - none).
2193 */
2194 sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>
2195 PNG_COST_SHIFT;
2196 sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>
2197 PNG_COST_SHIFT;
2198
2199 if (sumhi > PNG_HIMASK)
2200 sum = PNG_MAXSUM;
2201 else
2202 sum = (sumhi << PNG_HISHIFT) + sumlo;
2203 }
2204 #endif
2205 mins = sum;
2206 }
2207
2208 /* sub filter */
2209 if (filter_to_do == PNG_FILTER_SUB)
2210 /* it's the only filter so no testing is needed */
2211 {
2212 png_bytep rp, lp, dp;
2213 png_uint_32 i;
2214 for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
2215 i++, rp++, dp++)
2216 {
2217 *dp = *rp;
2218 }
2219 for (lp = row_buf + 1; i < row_bytes;
2220 i++, rp++, lp++, dp++)
2221 {
2222 *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
2223 }
2224 best_row = png_ptr->sub_row;
2225 }
2226
2227 else if (filter_to_do & PNG_FILTER_SUB)
2228 {
2229 png_bytep rp, dp, lp;
2230 png_uint_32 sum = 0, lmins = mins;
2231 png_uint_32 i;
2232 int v;
2233
2234 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2235 /* We temporarily increase the "minimum sum" by the factor we
2236 * would reduce the sum of this filter, so that we can do the
2237 * early exit comparison without scaling the sum each time.
2238 */
2239 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2240 {
2241 int j;
2242 png_uint_32 lmhi, lmlo;
2243 lmlo = lmins & PNG_LOMASK;
2244 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
2245
2246 for (j = 0; j < num_p_filters; j++)
2247 {
2248 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
2249 {
2250 lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
2251 PNG_WEIGHT_SHIFT;
2252 lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
2253 PNG_WEIGHT_SHIFT;
2254 }
2255 }
2256
2257 lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
2258 PNG_COST_SHIFT;
2259 lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
2260 PNG_COST_SHIFT;
2261
2262 if (lmhi > PNG_HIMASK)
2263 lmins = PNG_MAXSUM;
2264 else
2265 lmins = (lmhi << PNG_HISHIFT) + lmlo;
2266 }
2267 #endif
2268
2269 for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
2270 i++, rp++, dp++)
2271 {
2272 v = *dp = *rp;
2273
2274 sum += (v < 128) ? v : 256 - v;
2275 }
2276 for (lp = row_buf + 1; i < row_bytes;
2277 i++, rp++, lp++, dp++)
2278 {
2279 v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
2280
2281 sum += (v < 128) ? v : 256 - v;
2282
2283 if (sum > lmins) /* We are already worse, don't continue. */
2284 break;
2285 }
2286
2287 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2288 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2289 {
2290 int j;
2291 png_uint_32 sumhi, sumlo;
2292 sumlo = sum & PNG_LOMASK;
2293 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
2294
2295 for (j = 0; j < num_p_filters; j++)
2296 {
2297 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
2298 {
2299 sumlo = (sumlo * png_ptr->inv_filter_weights[j]) >>
2300 PNG_WEIGHT_SHIFT;
2301 sumhi = (sumhi * png_ptr->inv_filter_weights[j]) >>
2302 PNG_WEIGHT_SHIFT;
2303 }
2304 }
2305
2306 sumlo = (sumlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
2307 PNG_COST_SHIFT;
2308 sumhi = (sumhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
2309 PNG_COST_SHIFT;
2310
2311 if (sumhi > PNG_HIMASK)
2312 sum = PNG_MAXSUM;
2313 else
2314 sum = (sumhi << PNG_HISHIFT) + sumlo;
2315 }
2316 #endif
2317
2318 if (sum < mins)
2319 {
2320 mins = sum;
2321 best_row = png_ptr->sub_row;
2322 }
2323 }
2324
2325 /* up filter */
2326 if (filter_to_do == PNG_FILTER_UP)
2327 {
2328 png_bytep rp, dp, pp;
2329 png_uint_32 i;
2330
2331 for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
2332 pp = prev_row + 1; i < row_bytes;
2333 i++, rp++, pp++, dp++)
2334 {
2335 *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
2336 }
2337 best_row = png_ptr->up_row;
2338 }
2339
2340 else if (filter_to_do & PNG_FILTER_UP)
2341 {
2342 png_bytep rp, dp, pp;
2343 png_uint_32 sum = 0, lmins = mins;
2344 png_uint_32 i;
2345 int v;
2346
2347
2348 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2349 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2350 {
2351 int j;
2352 png_uint_32 lmhi, lmlo;
2353 lmlo = lmins & PNG_LOMASK;
2354 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
2355
2356 for (j = 0; j < num_p_filters; j++)
2357 {
2358 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
2359 {
2360 lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
2361 PNG_WEIGHT_SHIFT;
2362 lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
2363 PNG_WEIGHT_SHIFT;
2364 }
2365 }
2366
2367 lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
2368 PNG_COST_SHIFT;
2369 lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
2370 PNG_COST_SHIFT;
2371
2372 if (lmhi > PNG_HIMASK)
2373 lmins = PNG_MAXSUM;
2374 else
2375 lmins = (lmhi << PNG_HISHIFT) + lmlo;
2376 }
2377 #endif
2378
2379 for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
2380 pp = prev_row + 1; i < row_bytes; i++)
2381 {
2382 v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
2383
2384 sum += (v < 128) ? v : 256 - v;
2385
2386 if (sum > lmins) /* We are already worse, don't continue. */
2387 break;
2388 }
2389
2390 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2391 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2392 {
2393 int j;
2394 png_uint_32 sumhi, sumlo;
2395 sumlo = sum & PNG_LOMASK;
2396 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
2397
2398 for (j = 0; j < num_p_filters; j++)
2399 {
2400 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
2401 {
2402 sumlo = (sumlo * png_ptr->filter_weights[j]) >>
2403 PNG_WEIGHT_SHIFT;
2404 sumhi = (sumhi * png_ptr->filter_weights[j]) >>
2405 PNG_WEIGHT_SHIFT;
2406 }
2407 }
2408
2409 sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
2410 PNG_COST_SHIFT;
2411 sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
2412 PNG_COST_SHIFT;
2413
2414 if (sumhi > PNG_HIMASK)
2415 sum = PNG_MAXSUM;
2416 else
2417 sum = (sumhi << PNG_HISHIFT) + sumlo;
2418 }
2419 #endif
2420
2421 if (sum < mins)
2422 {
2423 mins = sum;
2424 best_row = png_ptr->up_row;
2425 }
2426 }
2427
2428 /* avg filter */
2429 if (filter_to_do == PNG_FILTER_AVG)
2430 {
2431 png_bytep rp, dp, pp, lp;
2432 png_uint_32 i;
2433 for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
2434 pp = prev_row + 1; i < bpp; i++)
2435 {
2436 *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
2437 }
2438 for (lp = row_buf + 1; i < row_bytes; i++)
2439 {
2440 *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
2441 & 0xff);
2442 }
2443 best_row = png_ptr->avg_row;
2444 }
2445
2446 else if (filter_to_do & PNG_FILTER_AVG)
2447 {
2448 png_bytep rp, dp, pp, lp;
2449 png_uint_32 sum = 0, lmins = mins;
2450 png_uint_32 i;
2451 int v;
2452
2453 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2454 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2455 {
2456 int j;
2457 png_uint_32 lmhi, lmlo;
2458 lmlo = lmins & PNG_LOMASK;
2459 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
2460
2461 for (j = 0; j < num_p_filters; j++)
2462 {
2463 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_AVG)
2464 {
2465 lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
2466 PNG_WEIGHT_SHIFT;
2467 lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
2468 PNG_WEIGHT_SHIFT;
2469 }
2470 }
2471
2472 lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
2473 PNG_COST_SHIFT;
2474 lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
2475 PNG_COST_SHIFT;
2476
2477 if (lmhi > PNG_HIMASK)
2478 lmins = PNG_MAXSUM;
2479 else
2480 lmins = (lmhi << PNG_HISHIFT) + lmlo;
2481 }
2482 #endif
2483
2484 for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
2485 pp = prev_row + 1; i < bpp; i++)
2486 {
2487 v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
2488
2489 sum += (v < 128) ? v : 256 - v;
2490 }
2491 for (lp = row_buf + 1; i < row_bytes; i++)
2492 {
2493 v = *dp++ =
2494 (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) & 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 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2503 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2504 {
2505 int j;
2506 png_uint_32 sumhi, sumlo;
2507 sumlo = sum & PNG_LOMASK;
2508 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
2509
2510 for (j = 0; j < num_p_filters; j++)
2511 {
2512 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
2513 {
2514 sumlo = (sumlo * png_ptr->filter_weights[j]) >>
2515 PNG_WEIGHT_SHIFT;
2516 sumhi = (sumhi * png_ptr->filter_weights[j]) >>
2517 PNG_WEIGHT_SHIFT;
2518 }
2519 }
2520
2521 sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
2522 PNG_COST_SHIFT;
2523 sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
2524 PNG_COST_SHIFT;
2525
2526 if (sumhi > PNG_HIMASK)
2527 sum = PNG_MAXSUM;
2528 else
2529 sum = (sumhi << PNG_HISHIFT) + sumlo;
2530 }
2531 #endif
2532
2533 if (sum < mins)
2534 {
2535 mins = sum;
2536 best_row = png_ptr->avg_row;
2537 }
2538 }
2539
2540 /* Paeth filter */
2541 if (filter_to_do == PNG_FILTER_PAETH)
2542 {
2543 png_bytep rp, dp, pp, cp, lp;
2544 png_uint_32 i;
2545 for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
2546 pp = prev_row + 1; i < bpp; i++)
2547 {
2548 *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
2549 }
2550
2551 for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
2552 {
2553 int a, b, c, pa, pb, pc, p;
2554
2555 b = *pp++;
2556 c = *cp++;
2557 a = *lp++;
2558
2559 p = b - c;
2560 pc = a - c;
2561
2562 #ifdef PNG_USE_ABS
2563 pa = abs(p);
2564 pb = abs(pc);
2565 pc = abs(p + pc);
2566 #else
2567 pa = p < 0 ? -p : p;
2568 pb = pc < 0 ? -pc : pc;
2569 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
2570 #endif
2571
2572 p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
2573
2574 *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
2575 }
2576 best_row = png_ptr->paeth_row;
2577 }
2578
2579 else if (filter_to_do & PNG_FILTER_PAETH)
2580 {
2581 png_bytep rp, dp, pp, cp, lp;
2582 png_uint_32 sum = 0, lmins = mins;
2583 png_uint_32 i;
2584 int v;
2585
2586 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2587 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2588 {
2589 int j;
2590 png_uint_32 lmhi, lmlo;
2591 lmlo = lmins & PNG_LOMASK;
2592 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
2593
2594 for (j = 0; j < num_p_filters; j++)
2595 {
2596 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
2597 {
2598 lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
2599 PNG_WEIGHT_SHIFT;
2600 lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
2601 PNG_WEIGHT_SHIFT;
2602 }
2603 }
2604
2605 lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>
2606 PNG_COST_SHIFT;
2607 lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>
2608 PNG_COST_SHIFT;
2609
2610 if (lmhi > PNG_HIMASK)
2611 lmins = PNG_MAXSUM;
2612 else
2613 lmins = (lmhi << PNG_HISHIFT) + lmlo;
2614 }
2615 #endif
2616
2617 for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
2618 pp = prev_row + 1; i < bpp; i++)
2619 {
2620 v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
2621
2622 sum += (v < 128) ? v : 256 - v;
2623 }
2624
2625 for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
2626 {
2627 int a, b, c, pa, pb, pc, p;
2628
2629 b = *pp++;
2630 c = *cp++;
2631 a = *lp++;
2632
2633 #ifndef PNG_SLOW_PAETH
2634 p = b - c;
2635 pc = a - c;
2636 #ifdef PNG_USE_ABS
2637 pa = abs(p);
2638 pb = abs(pc);
2639 pc = abs(p + pc);
2640 #else
2641 pa = p < 0 ? -p : p;
2642 pb = pc < 0 ? -pc : pc;
2643 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
2644 #endif
2645 p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
2646 #else /* PNG_SLOW_PAETH */
2647 p = a + b - c;
2648 pa = abs(p - a);
2649 pb = abs(p - b);
2650 pc = abs(p - c);
2651 if (pa <= pb && pa <= pc)
2652 p = a;
2653 else if (pb <= pc)
2654 p = b;
2655 else
2656 p = c;
2657 #endif /* PNG_SLOW_PAETH */
2658
2659 v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
2660
2661 sum += (v < 128) ? v : 256 - v;
2662
2663 if (sum > lmins) /* We are already worse, don't continue. */
2664 break;
2665 }
2666
2667 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2668 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2669 {
2670 int j;
2671 png_uint_32 sumhi, sumlo;
2672 sumlo = sum & PNG_LOMASK;
2673 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
2674
2675 for (j = 0; j < num_p_filters; j++)
2676 {
2677 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
2678 {
2679 sumlo = (sumlo * png_ptr->filter_weights[j]) >>
2680 PNG_WEIGHT_SHIFT;
2681 sumhi = (sumhi * png_ptr->filter_weights[j]) >>
2682 PNG_WEIGHT_SHIFT;
2683 }
2684 }
2685
2686 sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>
2687 PNG_COST_SHIFT;
2688 sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>
2689 PNG_COST_SHIFT;
2690
2691 if (sumhi > PNG_HIMASK)
2692 sum = PNG_MAXSUM;
2693 else
2694 sum = (sumhi << PNG_HISHIFT) + sumlo;
2695 }
2696 #endif
2697
2698 if (sum < mins)
2699 {
2700 best_row = png_ptr->paeth_row;
2701 }
2702 }
2703 #endif /* PNG_NO_WRITE_FILTER */
2704 /* Do the actual writing of the filtered row data from the chosen filter. */
2705
2706 png_write_filtered_row(png_ptr, best_row);
2707
2708 #ifndef PNG_NO_WRITE_FILTER
2709 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2710 /* Save the type of filter we picked this time for future calculations */
2711 if (png_ptr->num_prev_filters > 0)
2712 {
2713 int j;
2714 for (j = 1; j < num_p_filters; j++)
2715 {
2716 png_ptr->prev_filters[j] = png_ptr->prev_filters[j - 1];
2717 }
2718 png_ptr->prev_filters[j] = best_row[0];
2719 }
2720 #endif
2721 #endif /* PNG_NO_WRITE_FILTER */
2722 }
2723
2724
2725 /* Do the actual writing of a previously filtered row. */
2726 void /* PRIVATE */
2727 png_write_filtered_row(png_structp png_ptr, png_bytep filtered_row)
2728 {
2729 png_debug(1, "in png_write_filtered_row");
2730 png_debug1(2, "filter = %d", filtered_row[0]);
2731 /* set up the zlib input buffer */
2732
2733 png_ptr->zstream.next_in = filtered_row;
2734 png_ptr->zstream.avail_in = (uInt)png_ptr->row_info.rowbytes + 1;
2735 /* repeat until we have compressed all the data */
2736 do
2737 {
2738 int ret; /* return of zlib */
2739
2740 /* compress the data */
2741 ret = deflate(&png_ptr->zstream, Z_NO_FLUSH);
2742 /* check for compression errors */
2743 if (ret != Z_OK)
2744 {
2745 if (png_ptr->zstream.msg != NULL)
2746 png_error(png_ptr, png_ptr->zstream.msg);
2747 else
2748 png_error(png_ptr, "zlib error");
2749 }
2750
2751 /* see if it is time to write another IDAT */
2752 if (!(png_ptr->zstream.avail_out))
2753 {
2754 /* write the IDAT and reset the zlib output buffer */
2755 png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
2756 png_ptr->zstream.next_out = png_ptr->zbuf;
2757 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
2758 }
2759 /* repeat until all data has been compressed */
2760 } while (png_ptr->zstream.avail_in);
2761
2762 /* swap the current and previous rows */
2763 if (png_ptr->prev_row != NULL)
2764 {
2765 png_bytep tptr;
2766
2767 tptr = png_ptr->prev_row;
2768 png_ptr->prev_row = png_ptr->row_buf;
2769 png_ptr->row_buf = tptr;
2770 }
2771
2772 /* finish row - updates counters and flushes zlib if last row */
2773 png_write_finish_row(png_ptr);
2774
2775 #if defined(PNG_WRITE_FLUSH_SUPPORTED)
2776 png_ptr->flush_rows++;
2777
2778 if (png_ptr->flush_dist > 0 &&
2779 png_ptr->flush_rows >= png_ptr->flush_dist)
2780 {
2781 png_write_flush(png_ptr);
2782 }
2783 #endif
2784 }
2785 #endif /* PNG_WRITE_SUPPORTED */