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view libs/libpng/pngwutil.c @ 33:33e9eedad390
ah.. blunder
| author | John Tsiombikas <nuclear@mutantstargoat.com> |
|---|---|
| date | Fri, 09 Sep 2011 00:03:37 +0300 |
| parents | |
| children |
line source
2 /* pngwutil.c - utilities to write a PNG file
3 *
4 * Last changed in libpng 1.2.30 [August 15, 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 */
11 #define PNG_INTERNAL
12 #include "png.h"
13 #ifdef PNG_WRITE_SUPPORTED
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 }
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 }
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 }
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};
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 }
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 }
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];
99 png_debug2(0, "Writing %s chunk, length = %lu\n", chunk_name,
100 (unsigned long)length);
101 if (png_ptr == NULL) return;
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 }
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 }
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];
140 if (png_ptr == NULL) return;
142 /* write the crc in a single operation */
143 png_save_uint_32(buf, png_ptr->crc);
145 png_write_data(png_ptr, buf, (png_size_t)4);
146 }
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 */
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;
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;
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;
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 }
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 }
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 */
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;
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;
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;
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 }
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++;
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);
275 /* finish the compression */
276 do
277 {
278 /* tell zlib we are finished */
279 ret = deflate(&png_ptr->zstream, Z_FINISH);
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;
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;
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 }
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++;
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);
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;
340 return((int)text_len);
341 }
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;
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 }
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));
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
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;
393 png_byte buf[13]; /* buffer to store the IHDR info */
395 png_debug(1, "in png_write_IHDR\n");
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 }
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 }
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 }
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
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;
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;
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;
506 /* write the chunk */
507 png_write_chunk(png_ptr, (png_bytep)png_IHDR, buf, (png_size_t)13);
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;
555 png_ptr->mode = PNG_HAVE_IHDR;
556 }
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];
572 png_debug(1, "in png_write_PLTE\n");
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 }
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 }
597 png_ptr->num_palette = (png_uint_16)num_pal;
598 png_debug1(3, "num_palette = %d\n", png_ptr->num_palette);
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 }
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\n");
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 }
673 png_write_chunk(png_ptr, (png_bytep)png_IDAT, data, length);
674 png_ptr->mode |= PNG_HAVE_IDAT;
675 }
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\n");
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 }
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];
702 png_debug(1, "in png_write_gAMA\n");
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];
718 png_debug(1, "in png_write_gAMA\n");
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
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];
736 png_debug(1, "in png_write_sRGB\n");
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
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;
759 png_debug(1, "in png_write_iCCP\n");
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;
767 if (name == NULL || (name_len = png_check_keyword(png_ptr, name,
768 &new_name)) == 0)
769 {
770 png_warning(png_ptr, "Empty keyword in iCCP chunk");
771 return;
772 }
774 if (compression_type != PNG_COMPRESSION_TYPE_BASE)
775 png_warning(png_ptr, "Unknown compression type in iCCP chunk");
777 if (profile == NULL)
778 profile_len = 0;
780 if (profile_len > 3)
781 embedded_profile_len =
782 ((*( (png_bytep)profile ))<<24) |
783 ((*( (png_bytep)profile + 1))<<16) |
784 ((*( (png_bytep)profile + 2))<< 8) |
785 ((*( (png_bytep)profile + 3)) );
787 if (profile_len < embedded_profile_len)
788 {
789 png_warning(png_ptr,
790 "Embedded profile length too large in iCCP chunk");
791 return;
792 }
794 if (profile_len > embedded_profile_len)
795 {
796 png_warning(png_ptr,
797 "Truncating profile to actual length in iCCP chunk");
798 profile_len = embedded_profile_len;
799 }
801 if (profile_len)
802 profile_len = png_text_compress(png_ptr, profile,
803 (png_size_t)profile_len, PNG_COMPRESSION_TYPE_BASE, &comp);
805 /* make sure we include the NULL after the name and the compression type */
806 png_write_chunk_start(png_ptr, (png_bytep)png_iCCP,
807 (png_uint_32)(name_len + profile_len + 2));
808 new_name[name_len + 1] = 0x00;
809 png_write_chunk_data(png_ptr, (png_bytep)new_name,
810 (png_size_t)(name_len + 2));
812 if (profile_len)
813 png_write_compressed_data_out(png_ptr, &comp);
815 png_write_chunk_end(png_ptr);
816 png_free(png_ptr, new_name);
817 }
818 #endif
820 #if defined(PNG_WRITE_sPLT_SUPPORTED)
821 /* write a sPLT chunk */
822 void /* PRIVATE */
823 png_write_sPLT(png_structp png_ptr, png_sPLT_tp spalette)
824 {
825 #ifdef PNG_USE_LOCAL_ARRAYS
826 PNG_sPLT;
827 #endif
828 png_size_t name_len;
829 png_charp new_name;
830 png_byte entrybuf[10];
831 int entry_size = (spalette->depth == 8 ? 6 : 10);
832 int palette_size = entry_size * spalette->nentries;
833 png_sPLT_entryp ep;
834 #ifdef PNG_NO_POINTER_INDEXING
835 int i;
836 #endif
838 png_debug(1, "in png_write_sPLT\n");
839 if (spalette->name == NULL || (name_len = png_check_keyword(png_ptr,
840 spalette->name, &new_name))==0)
841 {
842 png_warning(png_ptr, "Empty keyword in sPLT chunk");
843 return;
844 }
846 /* make sure we include the NULL after the name */
847 png_write_chunk_start(png_ptr, (png_bytep)png_sPLT,
848 (png_uint_32)(name_len + 2 + palette_size));
849 png_write_chunk_data(png_ptr, (png_bytep)new_name,
850 (png_size_t)(name_len + 1));
851 png_write_chunk_data(png_ptr, (png_bytep)&spalette->depth, (png_size_t)1);
853 /* loop through each palette entry, writing appropriately */
854 #ifndef PNG_NO_POINTER_INDEXING
855 for (ep = spalette->entries; ep<spalette->entries + spalette->nentries; ep++)
856 {
857 if (spalette->depth == 8)
858 {
859 entrybuf[0] = (png_byte)ep->red;
860 entrybuf[1] = (png_byte)ep->green;
861 entrybuf[2] = (png_byte)ep->blue;
862 entrybuf[3] = (png_byte)ep->alpha;
863 png_save_uint_16(entrybuf + 4, ep->frequency);
864 }
865 else
866 {
867 png_save_uint_16(entrybuf + 0, ep->red);
868 png_save_uint_16(entrybuf + 2, ep->green);
869 png_save_uint_16(entrybuf + 4, ep->blue);
870 png_save_uint_16(entrybuf + 6, ep->alpha);
871 png_save_uint_16(entrybuf + 8, ep->frequency);
872 }
873 png_write_chunk_data(png_ptr, entrybuf, (png_size_t)entry_size);
874 }
875 #else
876 ep=spalette->entries;
877 for (i=0; i>spalette->nentries; i++)
878 {
879 if (spalette->depth == 8)
880 {
881 entrybuf[0] = (png_byte)ep[i].red;
882 entrybuf[1] = (png_byte)ep[i].green;
883 entrybuf[2] = (png_byte)ep[i].blue;
884 entrybuf[3] = (png_byte)ep[i].alpha;
885 png_save_uint_16(entrybuf + 4, ep[i].frequency);
886 }
887 else
888 {
889 png_save_uint_16(entrybuf + 0, ep[i].red);
890 png_save_uint_16(entrybuf + 2, ep[i].green);
891 png_save_uint_16(entrybuf + 4, ep[i].blue);
892 png_save_uint_16(entrybuf + 6, ep[i].alpha);
893 png_save_uint_16(entrybuf + 8, ep[i].frequency);
894 }
895 png_write_chunk_data(png_ptr, entrybuf, (png_size_t)entry_size);
896 }
897 #endif
899 png_write_chunk_end(png_ptr);
900 png_free(png_ptr, new_name);
901 }
902 #endif
904 #if defined(PNG_WRITE_sBIT_SUPPORTED)
905 /* write the sBIT chunk */
906 void /* PRIVATE */
907 png_write_sBIT(png_structp png_ptr, png_color_8p sbit, int color_type)
908 {
909 #ifdef PNG_USE_LOCAL_ARRAYS
910 PNG_sBIT;
911 #endif
912 png_byte buf[4];
913 png_size_t size;
915 png_debug(1, "in png_write_sBIT\n");
916 /* make sure we don't depend upon the order of PNG_COLOR_8 */
917 if (color_type & PNG_COLOR_MASK_COLOR)
918 {
919 png_byte maxbits;
921 maxbits = (png_byte)(color_type==PNG_COLOR_TYPE_PALETTE ? 8 :
922 png_ptr->usr_bit_depth);
923 if (sbit->red == 0 || sbit->red > maxbits ||
924 sbit->green == 0 || sbit->green > maxbits ||
925 sbit->blue == 0 || sbit->blue > maxbits)
926 {
927 png_warning(png_ptr, "Invalid sBIT depth specified");
928 return;
929 }
930 buf[0] = sbit->red;
931 buf[1] = sbit->green;
932 buf[2] = sbit->blue;
933 size = 3;
934 }
935 else
936 {
937 if (sbit->gray == 0 || sbit->gray > png_ptr->usr_bit_depth)
938 {
939 png_warning(png_ptr, "Invalid sBIT depth specified");
940 return;
941 }
942 buf[0] = sbit->gray;
943 size = 1;
944 }
946 if (color_type & PNG_COLOR_MASK_ALPHA)
947 {
948 if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth)
949 {
950 png_warning(png_ptr, "Invalid sBIT depth specified");
951 return;
952 }
953 buf[size++] = sbit->alpha;
954 }
956 png_write_chunk(png_ptr, (png_bytep)png_sBIT, buf, size);
957 }
958 #endif
960 #if defined(PNG_WRITE_cHRM_SUPPORTED)
961 /* write the cHRM chunk */
962 #ifdef PNG_FLOATING_POINT_SUPPORTED
963 void /* PRIVATE */
964 png_write_cHRM(png_structp png_ptr, double white_x, double white_y,
965 double red_x, double red_y, double green_x, double green_y,
966 double blue_x, double blue_y)
967 {
968 #ifdef PNG_USE_LOCAL_ARRAYS
969 PNG_cHRM;
970 #endif
971 png_byte buf[32];
972 png_uint_32 itemp;
974 png_debug(1, "in png_write_cHRM\n");
975 /* each value is saved in 1/100,000ths */
976 if (white_x < 0 || white_x > 0.8 || white_y < 0 || white_y > 0.8 ||
977 white_x + white_y > 1.0)
978 {
979 png_warning(png_ptr, "Invalid cHRM white point specified");
980 #if !defined(PNG_NO_CONSOLE_IO)
981 fprintf(stderr, "white_x=%f, white_y=%f\n", white_x, white_y);
982 #endif
983 return;
984 }
985 itemp = (png_uint_32)(white_x * 100000.0 + 0.5);
986 png_save_uint_32(buf, itemp);
987 itemp = (png_uint_32)(white_y * 100000.0 + 0.5);
988 png_save_uint_32(buf + 4, itemp);
990 if (red_x < 0 || red_y < 0 || red_x + red_y > 1.0)
991 {
992 png_warning(png_ptr, "Invalid cHRM red point specified");
993 return;
994 }
995 itemp = (png_uint_32)(red_x * 100000.0 + 0.5);
996 png_save_uint_32(buf + 8, itemp);
997 itemp = (png_uint_32)(red_y * 100000.0 + 0.5);
998 png_save_uint_32(buf + 12, itemp);
1000 if (green_x < 0 || green_y < 0 || green_x + green_y > 1.0)
1001 {
1002 png_warning(png_ptr, "Invalid cHRM green point specified");
1003 return;
1004 }
1005 itemp = (png_uint_32)(green_x * 100000.0 + 0.5);
1006 png_save_uint_32(buf + 16, itemp);
1007 itemp = (png_uint_32)(green_y * 100000.0 + 0.5);
1008 png_save_uint_32(buf + 20, itemp);
1010 if (blue_x < 0 || blue_y < 0 || blue_x + blue_y > 1.0)
1011 {
1012 png_warning(png_ptr, "Invalid cHRM blue point specified");
1013 return;
1014 }
1015 itemp = (png_uint_32)(blue_x * 100000.0 + 0.5);
1016 png_save_uint_32(buf + 24, itemp);
1017 itemp = (png_uint_32)(blue_y * 100000.0 + 0.5);
1018 png_save_uint_32(buf + 28, itemp);
1020 png_write_chunk(png_ptr, (png_bytep)png_cHRM, buf, (png_size_t)32);
1021 }
1022 #endif
1023 #ifdef PNG_FIXED_POINT_SUPPORTED
1024 void /* PRIVATE */
1025 png_write_cHRM_fixed(png_structp png_ptr, png_fixed_point white_x,
1026 png_fixed_point white_y, png_fixed_point red_x, png_fixed_point red_y,
1027 png_fixed_point green_x, png_fixed_point green_y, png_fixed_point blue_x,
1028 png_fixed_point blue_y)
1029 {
1030 #ifdef PNG_USE_LOCAL_ARRAYS
1031 PNG_cHRM;
1032 #endif
1033 png_byte buf[32];
1035 png_debug(1, "in png_write_cHRM\n");
1036 /* each value is saved in 1/100,000ths */
1037 if (white_x > 80000L || white_y > 80000L || white_x + white_y > 100000L)
1038 {
1039 png_warning(png_ptr, "Invalid fixed cHRM white point specified");
1040 #if !defined(PNG_NO_CONSOLE_IO)
1041 fprintf(stderr, "white_x=%ld, white_y=%ld\n", (unsigned long)white_x,
1042 (unsigned long)white_y);
1043 #endif
1044 return;
1045 }
1046 png_save_uint_32(buf, (png_uint_32)white_x);
1047 png_save_uint_32(buf + 4, (png_uint_32)white_y);
1049 if (red_x + red_y > 100000L)
1050 {
1051 png_warning(png_ptr, "Invalid cHRM fixed red point specified");
1052 return;
1053 }
1054 png_save_uint_32(buf + 8, (png_uint_32)red_x);
1055 png_save_uint_32(buf + 12, (png_uint_32)red_y);
1057 if (green_x + green_y > 100000L)
1058 {
1059 png_warning(png_ptr, "Invalid fixed cHRM green point specified");
1060 return;
1061 }
1062 png_save_uint_32(buf + 16, (png_uint_32)green_x);
1063 png_save_uint_32(buf + 20, (png_uint_32)green_y);
1065 if (blue_x + blue_y > 100000L)
1066 {
1067 png_warning(png_ptr, "Invalid fixed cHRM blue point specified");
1068 return;
1069 }
1070 png_save_uint_32(buf + 24, (png_uint_32)blue_x);
1071 png_save_uint_32(buf + 28, (png_uint_32)blue_y);
1073 png_write_chunk(png_ptr, (png_bytep)png_cHRM, buf, (png_size_t)32);
1074 }
1075 #endif
1076 #endif
1078 #if defined(PNG_WRITE_tRNS_SUPPORTED)
1079 /* write the tRNS chunk */
1080 void /* PRIVATE */
1081 png_write_tRNS(png_structp png_ptr, png_bytep trans, png_color_16p tran,
1082 int num_trans, int color_type)
1083 {
1084 #ifdef PNG_USE_LOCAL_ARRAYS
1085 PNG_tRNS;
1086 #endif
1087 png_byte buf[6];
1089 png_debug(1, "in png_write_tRNS\n");
1090 if (color_type == PNG_COLOR_TYPE_PALETTE)
1091 {
1092 if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette)
1093 {
1094 png_warning(png_ptr, "Invalid number of transparent colors specified");
1095 return;
1096 }
1097 /* write the chunk out as it is */
1098 png_write_chunk(png_ptr, (png_bytep)png_tRNS, trans,
1099 (png_size_t)num_trans);
1100 }
1101 else if (color_type == PNG_COLOR_TYPE_GRAY)
1102 {
1103 /* one 16 bit value */
1104 if (tran->gray >= (1 << png_ptr->bit_depth))
1105 {
1106 png_warning(png_ptr,
1107 "Ignoring attempt to write tRNS chunk out-of-range for bit_depth");
1108 return;
1109 }
1110 png_save_uint_16(buf, tran->gray);
1111 png_write_chunk(png_ptr, (png_bytep)png_tRNS, buf, (png_size_t)2);
1112 }
1113 else if (color_type == PNG_COLOR_TYPE_RGB)
1114 {
1115 /* three 16 bit values */
1116 png_save_uint_16(buf, tran->red);
1117 png_save_uint_16(buf + 2, tran->green);
1118 png_save_uint_16(buf + 4, tran->blue);
1119 if (png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
1120 {
1121 png_warning(png_ptr,
1122 "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8");
1123 return;
1124 }
1125 png_write_chunk(png_ptr, (png_bytep)png_tRNS, buf, (png_size_t)6);
1126 }
1127 else
1128 {
1129 png_warning(png_ptr, "Can't write tRNS with an alpha channel");
1130 }
1131 }
1132 #endif
1134 #if defined(PNG_WRITE_bKGD_SUPPORTED)
1135 /* write the background chunk */
1136 void /* PRIVATE */
1137 png_write_bKGD(png_structp png_ptr, png_color_16p back, int color_type)
1138 {
1139 #ifdef PNG_USE_LOCAL_ARRAYS
1140 PNG_bKGD;
1141 #endif
1142 png_byte buf[6];
1144 png_debug(1, "in png_write_bKGD\n");
1145 if (color_type == PNG_COLOR_TYPE_PALETTE)
1146 {
1147 if (
1148 #if defined(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
1187 #if defined(PNG_WRITE_hIST_SUPPORTED)
1188 /* write the histogram */
1189 void /* PRIVATE */
1190 png_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];
1198 png_debug(1, "in png_write_hIST\n");
1199 if (num_hist > (int)png_ptr->num_palette)
1200 {
1201 png_debug2(3, "num_hist = %d, num_palette = %d\n", num_hist,
1202 png_ptr->num_palette);
1203 png_warning(png_ptr, "Invalid number of histogram entries specified");
1204 return;
1205 }
1207 png_write_chunk_start(png_ptr, (png_bytep)png_hIST,
1208 (png_uint_32)(num_hist * 2));
1209 for (i = 0; i < num_hist; i++)
1210 {
1211 png_save_uint_16(buf, hist[i]);
1212 png_write_chunk_data(png_ptr, buf, (png_size_t)2);
1213 }
1214 png_write_chunk_end(png_ptr);
1215 }
1216 #endif
1218 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \
1219 defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
1220 /* Check that the tEXt or zTXt keyword is valid per PNG 1.0 specification,
1221 * and if invalid, correct the keyword rather than discarding the entire
1222 * chunk. The PNG 1.0 specification requires keywords 1-79 characters in
1223 * length, forbids leading or trailing whitespace, multiple internal spaces,
1224 * and the non-break space (0x80) from ISO 8859-1. Returns keyword length.
1225 *
1226 * The new_key is allocated to hold the corrected keyword and must be freed
1227 * by the calling routine. This avoids problems with trying to write to
1228 * static keywords without having to have duplicate copies of the strings.
1229 */
1230 png_size_t /* PRIVATE */
1231 png_check_keyword(png_structp png_ptr, png_charp key, png_charpp new_key)
1232 {
1233 png_size_t key_len;
1234 png_charp kp, dp;
1235 int kflag;
1236 int kwarn=0;
1238 png_debug(1, "in png_check_keyword\n");
1239 *new_key = NULL;
1241 if (key == NULL || (key_len = png_strlen(key)) == 0)
1242 {
1243 png_warning(png_ptr, "zero length keyword");
1244 return ((png_size_t)0);
1245 }
1247 png_debug1(2, "Keyword to be checked is '%s'\n", key);
1249 *new_key = (png_charp)png_malloc_warn(png_ptr, (png_uint_32)(key_len + 2));
1250 if (*new_key == NULL)
1251 {
1252 png_warning(png_ptr, "Out of memory while procesing keyword");
1253 return ((png_size_t)0);
1254 }
1256 /* Replace non-printing characters with a blank and print a warning */
1257 for (kp = key, dp = *new_key; *kp != '\0'; kp++, dp++)
1258 {
1259 if ((png_byte)*kp < 0x20 ||
1260 ((png_byte)*kp > 0x7E && (png_byte)*kp < 0xA1))
1261 {
1262 #if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
1263 char msg[40];
1265 png_snprintf(msg, 40,
1266 "invalid keyword character 0x%02X", (png_byte)*kp);
1267 png_warning(png_ptr, msg);
1268 #else
1269 png_warning(png_ptr, "invalid character in keyword");
1270 #endif
1271 *dp = ' ';
1272 }
1273 else
1274 {
1275 *dp = *kp;
1276 }
1277 }
1278 *dp = '\0';
1280 /* Remove any trailing white space. */
1281 kp = *new_key + key_len - 1;
1282 if (*kp == ' ')
1283 {
1284 png_warning(png_ptr, "trailing spaces removed from keyword");
1286 while (*kp == ' ')
1287 {
1288 *(kp--) = '\0';
1289 key_len--;
1290 }
1291 }
1293 /* Remove any leading white space. */
1294 kp = *new_key;
1295 if (*kp == ' ')
1296 {
1297 png_warning(png_ptr, "leading spaces removed from keyword");
1299 while (*kp == ' ')
1300 {
1301 kp++;
1302 key_len--;
1303 }
1304 }
1306 png_debug1(2, "Checking for multiple internal spaces in '%s'\n", kp);
1308 /* Remove multiple internal spaces. */
1309 for (kflag = 0, dp = *new_key; *kp != '\0'; kp++)
1310 {
1311 if (*kp == ' ' && kflag == 0)
1312 {
1313 *(dp++) = *kp;
1314 kflag = 1;
1315 }
1316 else if (*kp == ' ')
1317 {
1318 key_len--;
1319 kwarn=1;
1320 }
1321 else
1322 {
1323 *(dp++) = *kp;
1324 kflag = 0;
1325 }
1326 }
1327 *dp = '\0';
1328 if (kwarn)
1329 png_warning(png_ptr, "extra interior spaces removed from keyword");
1331 if (key_len == 0)
1332 {
1333 png_free(png_ptr, *new_key);
1334 *new_key=NULL;
1335 png_warning(png_ptr, "Zero length keyword");
1336 }
1338 if (key_len > 79)
1339 {
1340 png_warning(png_ptr, "keyword length must be 1 - 79 characters");
1341 new_key[79] = '\0';
1342 key_len = 79;
1343 }
1345 return (key_len);
1346 }
1347 #endif
1349 #if defined(PNG_WRITE_tEXt_SUPPORTED)
1350 /* write a tEXt chunk */
1351 void /* PRIVATE */
1352 png_write_tEXt(png_structp png_ptr, png_charp key, png_charp text,
1353 png_size_t text_len)
1354 {
1355 #ifdef PNG_USE_LOCAL_ARRAYS
1356 PNG_tEXt;
1357 #endif
1358 png_size_t key_len;
1359 png_charp new_key;
1361 png_debug(1, "in png_write_tEXt\n");
1362 if (key == NULL || (key_len = png_check_keyword(png_ptr, key, &new_key))==0)
1363 {
1364 png_warning(png_ptr, "Empty keyword in tEXt chunk");
1365 return;
1366 }
1368 if (text == NULL || *text == '\0')
1369 text_len = 0;
1370 else
1371 text_len = png_strlen(text);
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);
1387 png_write_chunk_end(png_ptr);
1388 png_free(png_ptr, new_key);
1389 }
1390 #endif
1392 #if defined(PNG_WRITE_zTXt_SUPPORTED)
1393 /* write a compressed text chunk */
1394 void /* PRIVATE */
1395 png_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;
1406 png_debug(1, "in png_write_zTXt\n");
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;
1414 if (key == NULL || (key_len = png_check_keyword(png_ptr, key, &new_key))==0)
1415 {
1416 png_warning(png_ptr, "Empty keyword in zTXt chunk");
1417 png_free(png_ptr, new_key);
1418 return;
1419 }
1421 if (text == NULL || *text == '\0' || compression==PNG_TEXT_COMPRESSION_NONE)
1422 {
1423 png_write_tEXt(png_ptr, new_key, text, (png_size_t)0);
1424 png_free(png_ptr, new_key);
1425 return;
1426 }
1428 text_len = png_strlen(text);
1430 /* compute the compressed data; do it now for the length */
1431 text_len = png_text_compress(png_ptr, text, text_len, compression,
1432 &comp);
1434 /* write start of chunk */
1435 png_write_chunk_start(png_ptr, (png_bytep)png_zTXt,
1436 (png_uint_32)(key_len+text_len + 2));
1437 /* write key */
1438 png_write_chunk_data(png_ptr, (png_bytep)new_key,
1439 (png_size_t)(key_len + 1));
1440 png_free(png_ptr, new_key);
1442 buf[0] = (png_byte)compression;
1443 /* write compression */
1444 png_write_chunk_data(png_ptr, (png_bytep)buf, (png_size_t)1);
1445 /* write the compressed data */
1446 png_write_compressed_data_out(png_ptr, &comp);
1448 /* close the chunk */
1449 png_write_chunk_end(png_ptr);
1450 }
1451 #endif
1453 #if defined(PNG_WRITE_iTXt_SUPPORTED)
1454 /* write an iTXt chunk */
1455 void /* PRIVATE */
1456 png_write_iTXt(png_structp png_ptr, int compression, png_charp key,
1457 png_charp lang, png_charp lang_key, png_charp text)
1458 {
1459 #ifdef PNG_USE_LOCAL_ARRAYS
1460 PNG_iTXt;
1461 #endif
1462 png_size_t lang_len, key_len, lang_key_len, text_len;
1463 png_charp new_lang, new_key;
1464 png_byte cbuf[2];
1465 compression_state comp;
1467 png_debug(1, "in png_write_iTXt\n");
1469 comp.num_output_ptr = 0;
1470 comp.max_output_ptr = 0;
1471 comp.output_ptr = NULL;
1472 comp.input = NULL;
1474 if (key == NULL || (key_len = png_check_keyword(png_ptr, key, &new_key))==0)
1475 {
1476 png_warning(png_ptr, "Empty keyword in iTXt chunk");
1477 return;
1478 }
1479 if (lang == NULL || (lang_len = png_check_keyword(png_ptr, lang, &new_lang))==0)
1480 {
1481 png_warning(png_ptr, "Empty language field in iTXt chunk");
1482 new_lang = NULL;
1483 lang_len = 0;
1484 }
1486 if (lang_key == NULL)
1487 lang_key_len = 0;
1488 else
1489 lang_key_len = png_strlen(lang_key);
1491 if (text == NULL)
1492 text_len = 0;
1493 else
1494 text_len = png_strlen(text);
1496 /* compute the compressed data; do it now for the length */
1497 text_len = png_text_compress(png_ptr, text, text_len, compression-2,
1498 &comp);
1501 /* make sure we include the compression flag, the compression byte,
1502 * and the NULs after the key, lang, and lang_key parts */
1504 png_write_chunk_start(png_ptr, (png_bytep)png_iTXt,
1505 (png_uint_32)(
1506 5 /* comp byte, comp flag, terminators for key, lang and lang_key */
1507 + key_len
1508 + lang_len
1509 + lang_key_len
1510 + text_len));
1512 /*
1513 * We leave it to the application to meet PNG-1.0 requirements on the
1514 * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of
1515 * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them.
1516 * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
1517 */
1518 png_write_chunk_data(png_ptr, (png_bytep)new_key,
1519 (png_size_t)(key_len + 1));
1521 /* set the compression flag */
1522 if (compression == PNG_ITXT_COMPRESSION_NONE || \
1523 compression == PNG_TEXT_COMPRESSION_NONE)
1524 cbuf[0] = 0;
1525 else /* compression == PNG_ITXT_COMPRESSION_zTXt */
1526 cbuf[0] = 1;
1527 /* set the compression method */
1528 cbuf[1] = 0;
1529 png_write_chunk_data(png_ptr, cbuf, (png_size_t)2);
1531 cbuf[0] = 0;
1532 png_write_chunk_data(png_ptr, (new_lang ? (png_bytep)new_lang : cbuf),
1533 (png_size_t)(lang_len + 1));
1534 png_write_chunk_data(png_ptr, (lang_key ? (png_bytep)lang_key : cbuf),
1535 (png_size_t)(lang_key_len + 1));
1536 png_write_compressed_data_out(png_ptr, &comp);
1538 png_write_chunk_end(png_ptr);
1539 png_free(png_ptr, new_key);
1540 png_free(png_ptr, new_lang);
1541 }
1542 #endif
1544 #if defined(PNG_WRITE_oFFs_SUPPORTED)
1545 /* write the oFFs chunk */
1546 void /* PRIVATE */
1547 png_write_oFFs(png_structp png_ptr, png_int_32 x_offset, png_int_32 y_offset,
1548 int unit_type)
1549 {
1550 #ifdef PNG_USE_LOCAL_ARRAYS
1551 PNG_oFFs;
1552 #endif
1553 png_byte buf[9];
1555 png_debug(1, "in png_write_oFFs\n");
1556 if (unit_type >= PNG_OFFSET_LAST)
1557 png_warning(png_ptr, "Unrecognized unit type for oFFs chunk");
1559 png_save_int_32(buf, x_offset);
1560 png_save_int_32(buf + 4, y_offset);
1561 buf[8] = (png_byte)unit_type;
1563 png_write_chunk(png_ptr, (png_bytep)png_oFFs, buf, (png_size_t)9);
1564 }
1565 #endif
1566 #if defined(PNG_WRITE_pCAL_SUPPORTED)
1567 /* write the pCAL chunk (described in the PNG extensions document) */
1568 void /* PRIVATE */
1569 png_write_pCAL(png_structp png_ptr, png_charp purpose, png_int_32 X0,
1570 png_int_32 X1, int type, int nparams, png_charp units, png_charpp params)
1571 {
1572 #ifdef PNG_USE_LOCAL_ARRAYS
1573 PNG_pCAL;
1574 #endif
1575 png_size_t purpose_len, units_len, total_len;
1576 png_uint_32p params_len;
1577 png_byte buf[10];
1578 png_charp new_purpose;
1579 int i;
1581 png_debug1(1, "in png_write_pCAL (%d parameters)\n", nparams);
1582 if (type >= PNG_EQUATION_LAST)
1583 png_warning(png_ptr, "Unrecognized equation type for pCAL chunk");
1585 purpose_len = png_check_keyword(png_ptr, purpose, &new_purpose) + 1;
1586 png_debug1(3, "pCAL purpose length = %d\n", (int)purpose_len);
1587 units_len = png_strlen(units) + (nparams == 0 ? 0 : 1);
1588 png_debug1(3, "pCAL units length = %d\n", (int)units_len);
1589 total_len = purpose_len + units_len + 10;
1591 params_len = (png_uint_32p)png_malloc(png_ptr,
1592 (png_uint_32)(nparams * png_sizeof(png_uint_32)));
1594 /* Find the length of each parameter, making sure we don't count the
1595 null terminator for the last parameter. */
1596 for (i = 0; i < nparams; i++)
1597 {
1598 params_len[i] = png_strlen(params[i]) + (i == nparams - 1 ? 0 : 1);
1599 png_debug2(3, "pCAL parameter %d length = %lu\n", i,
1600 (unsigned long) params_len[i]);
1601 total_len += (png_size_t)params_len[i];
1602 }
1604 png_debug1(3, "pCAL total length = %d\n", (int)total_len);
1605 png_write_chunk_start(png_ptr, (png_bytep)png_pCAL, (png_uint_32)total_len);
1606 png_write_chunk_data(png_ptr, (png_bytep)new_purpose,
1607 (png_size_t)purpose_len);
1608 png_save_int_32(buf, X0);
1609 png_save_int_32(buf + 4, X1);
1610 buf[8] = (png_byte)type;
1611 buf[9] = (png_byte)nparams;
1612 png_write_chunk_data(png_ptr, buf, (png_size_t)10);
1613 png_write_chunk_data(png_ptr, (png_bytep)units, (png_size_t)units_len);
1615 png_free(png_ptr, new_purpose);
1617 for (i = 0; i < nparams; i++)
1618 {
1619 png_write_chunk_data(png_ptr, (png_bytep)params[i],
1620 (png_size_t)params_len[i]);
1621 }
1623 png_free(png_ptr, params_len);
1624 png_write_chunk_end(png_ptr);
1625 }
1626 #endif
1628 #if defined(PNG_WRITE_sCAL_SUPPORTED)
1629 /* write the sCAL chunk */
1630 #if defined(PNG_FLOATING_POINT_SUPPORTED) && !defined(PNG_NO_STDIO)
1631 void /* PRIVATE */
1632 png_write_sCAL(png_structp png_ptr, int unit, double width, double height)
1633 {
1634 #ifdef PNG_USE_LOCAL_ARRAYS
1635 PNG_sCAL;
1636 #endif
1637 char buf[64];
1638 png_size_t total_len;
1640 png_debug(1, "in png_write_sCAL\n");
1642 buf[0] = (char)unit;
1643 #if defined(_WIN32_WCE)
1644 /* sprintf() function is not supported on WindowsCE */
1645 {
1646 wchar_t wc_buf[32];
1647 size_t wc_len;
1648 swprintf(wc_buf, TEXT("%12.12e"), width);
1649 wc_len = wcslen(wc_buf);
1650 WideCharToMultiByte(CP_ACP, 0, wc_buf, -1, buf + 1, wc_len, NULL, 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
1665 png_debug1(3, "sCAL total length = %u\n", (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
1670 void /* PRIVATE */
1671 png_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;
1680 png_debug(1, "in png_write_sCAL_s\n");
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 }
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 */
1695 png_debug1(3, "sCAL total length = %u\n", (unsigned int)total_len);
1696 png_write_chunk(png_ptr, (png_bytep)png_sCAL, buf, total_len);
1697 }
1698 #endif
1699 #endif
1700 #endif
1702 #if defined(PNG_WRITE_pHYs_SUPPORTED)
1703 /* write the pHYs chunk */
1704 void /* PRIVATE */
1705 png_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];
1714 png_debug(1, "in png_write_pHYs\n");
1715 if (unit_type >= PNG_RESOLUTION_LAST)
1716 png_warning(png_ptr, "Unrecognized unit type for pHYs chunk");
1718 png_save_uint_32(buf, x_pixels_per_unit);
1719 png_save_uint_32(buf + 4, y_pixels_per_unit);
1720 buf[8] = (png_byte)unit_type;
1722 png_write_chunk(png_ptr, (png_bytep)png_pHYs, buf, (png_size_t)9);
1723 }
1724 #endif
1726 #if defined(PNG_WRITE_tIME_SUPPORTED)
1727 /* Write the tIME chunk. Use either png_convert_from_struct_tm()
1728 * or png_convert_from_time_t(), or fill in the structure yourself.
1729 */
1730 void /* PRIVATE */
1731 png_write_tIME(png_structp png_ptr, png_timep mod_time)
1732 {
1733 #ifdef PNG_USE_LOCAL_ARRAYS
1734 PNG_tIME;
1735 #endif
1736 png_byte buf[7];
1738 png_debug(1, "in png_write_tIME\n");
1739 if (mod_time->month > 12 || mod_time->month < 1 ||
1740 mod_time->day > 31 || mod_time->day < 1 ||
1741 mod_time->hour > 23 || mod_time->second > 60)
1742 {
1743 png_warning(png_ptr, "Invalid time specified for tIME chunk");
1744 return;
1745 }
1747 png_save_uint_16(buf, mod_time->year);
1748 buf[2] = mod_time->month;
1749 buf[3] = mod_time->day;
1750 buf[4] = mod_time->hour;
1751 buf[5] = mod_time->minute;
1752 buf[6] = mod_time->second;
1754 png_write_chunk(png_ptr, (png_bytep)png_tIME, buf, (png_size_t)7);
1755 }
1756 #endif
1758 /* initializes the row writing capability of libpng */
1759 void /* PRIVATE */
1760 png_write_start_row(png_structp png_ptr)
1761 {
1762 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1763 #ifdef PNG_USE_LOCAL_ARRAYS
1764 /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
1766 /* start of interlace block */
1767 int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
1769 /* offset to next interlace block */
1770 int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
1772 /* start of interlace block in the y direction */
1773 int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
1775 /* offset to next interlace block in the y direction */
1776 int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
1777 #endif
1778 #endif
1780 png_size_t buf_size;
1782 png_debug(1, "in png_write_start_row\n");
1783 buf_size = (png_size_t)(PNG_ROWBYTES(
1784 png_ptr->usr_channels*png_ptr->usr_bit_depth, png_ptr->width) + 1);
1786 /* set up row buffer */
1787 png_ptr->row_buf = (png_bytep)png_malloc(png_ptr,
1788 (png_uint_32)buf_size);
1789 png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE;
1791 #ifndef PNG_NO_WRITE_FILTER
1792 /* set up filtering buffer, if using this filter */
1793 if (png_ptr->do_filter & PNG_FILTER_SUB)
1794 {
1795 png_ptr->sub_row = (png_bytep)png_malloc(png_ptr,
1796 (png_uint_32)(png_ptr->rowbytes + 1));
1797 png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
1798 }
1800 /* We only need to keep the previous row if we are using one of these. */
1801 if (png_ptr->do_filter & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH))
1802 {
1803 /* set up previous row buffer */
1804 png_ptr->prev_row = (png_bytep)png_malloc(png_ptr,
1805 (png_uint_32)buf_size);
1806 png_memset(png_ptr->prev_row, 0, buf_size);
1808 if (png_ptr->do_filter & PNG_FILTER_UP)
1809 {
1810 png_ptr->up_row = (png_bytep)png_malloc(png_ptr,
1811 (png_uint_32)(png_ptr->rowbytes + 1));
1812 png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
1813 }
1815 if (png_ptr->do_filter & PNG_FILTER_AVG)
1816 {
1817 png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
1818 (png_uint_32)(png_ptr->rowbytes + 1));
1819 png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
1820 }
1822 if (png_ptr->do_filter & PNG_FILTER_PAETH)
1823 {
1824 png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,
1825 (png_uint_32)(png_ptr->rowbytes + 1));
1826 png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
1827 }
1828 }
1829 #endif /* PNG_NO_WRITE_FILTER */
1831 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1832 /* if interlaced, we need to set up width and height of pass */
1833 if (png_ptr->interlaced)
1834 {
1835 if (!(png_ptr->transformations & PNG_INTERLACE))
1836 {
1837 png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
1838 png_pass_ystart[0]) / png_pass_yinc[0];
1839 png_ptr->usr_width = (png_ptr->width + png_pass_inc[0] - 1 -
1840 png_pass_start[0]) / png_pass_inc[0];
1841 }
1842 else
1843 {
1844 png_ptr->num_rows = png_ptr->height;
1845 png_ptr->usr_width = png_ptr->width;
1846 }
1847 }
1848 else
1849 #endif
1850 {
1851 png_ptr->num_rows = png_ptr->height;
1852 png_ptr->usr_width = png_ptr->width;
1853 }
1854 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1855 png_ptr->zstream.next_out = png_ptr->zbuf;
1856 }
1858 /* Internal use only. Called when finished processing a row of data. */
1859 void /* PRIVATE */
1860 png_write_finish_row(png_structp png_ptr)
1861 {
1862 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1863 #ifdef PNG_USE_LOCAL_ARRAYS
1864 /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
1866 /* start of interlace block */
1867 int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
1869 /* offset to next interlace block */
1870 int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
1872 /* start of interlace block in the y direction */
1873 int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
1875 /* offset to next interlace block in the y direction */
1876 int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
1877 #endif
1878 #endif
1880 int ret;
1882 png_debug(1, "in png_write_finish_row\n");
1883 /* next row */
1884 png_ptr->row_number++;
1886 /* see if we are done */
1887 if (png_ptr->row_number < png_ptr->num_rows)
1888 return;
1890 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1891 /* if interlaced, go to next pass */
1892 if (png_ptr->interlaced)
1893 {
1894 png_ptr->row_number = 0;
1895 if (png_ptr->transformations & PNG_INTERLACE)
1896 {
1897 png_ptr->pass++;
1898 }
1899 else
1900 {
1901 /* loop until we find a non-zero width or height pass */
1902 do
1903 {
1904 png_ptr->pass++;
1905 if (png_ptr->pass >= 7)
1906 break;
1907 png_ptr->usr_width = (png_ptr->width +
1908 png_pass_inc[png_ptr->pass] - 1 -
1909 png_pass_start[png_ptr->pass]) /
1910 png_pass_inc[png_ptr->pass];
1911 png_ptr->num_rows = (png_ptr->height +
1912 png_pass_yinc[png_ptr->pass] - 1 -
1913 png_pass_ystart[png_ptr->pass]) /
1914 png_pass_yinc[png_ptr->pass];
1915 if (png_ptr->transformations & PNG_INTERLACE)
1916 break;
1917 } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0);
1919 }
1921 /* reset the row above the image for the next pass */
1922 if (png_ptr->pass < 7)
1923 {
1924 if (png_ptr->prev_row != NULL)
1925 png_memset(png_ptr->prev_row, 0,
1926 (png_size_t)(PNG_ROWBYTES(png_ptr->usr_channels*
1927 png_ptr->usr_bit_depth, png_ptr->width)) + 1);
1928 return;
1929 }
1930 }
1931 #endif
1933 /* if we get here, we've just written the last row, so we need
1934 to flush the compressor */
1935 do
1936 {
1937 /* tell the compressor we are done */
1938 ret = deflate(&png_ptr->zstream, Z_FINISH);
1939 /* check for an error */
1940 if (ret == Z_OK)
1941 {
1942 /* check to see if we need more room */
1943 if (!(png_ptr->zstream.avail_out))
1944 {
1945 png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
1946 png_ptr->zstream.next_out = png_ptr->zbuf;
1947 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1948 }
1949 }
1950 else if (ret != Z_STREAM_END)
1951 {
1952 if (png_ptr->zstream.msg != NULL)
1953 png_error(png_ptr, png_ptr->zstream.msg);
1954 else
1955 png_error(png_ptr, "zlib error");
1956 }
1957 } while (ret != Z_STREAM_END);
1959 /* write any extra space */
1960 if (png_ptr->zstream.avail_out < png_ptr->zbuf_size)
1961 {
1962 png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size -
1963 png_ptr->zstream.avail_out);
1964 }
1966 deflateReset(&png_ptr->zstream);
1967 png_ptr->zstream.data_type = Z_BINARY;
1968 }
1970 #if defined(PNG_WRITE_INTERLACING_SUPPORTED)
1971 /* Pick out the correct pixels for the interlace pass.
1972 * The basic idea here is to go through the row with a source
1973 * pointer and a destination pointer (sp and dp), and copy the
1974 * correct pixels for the pass. As the row gets compacted,
1975 * sp will always be >= dp, so we should never overwrite anything.
1976 * See the default: case for the easiest code to understand.
1977 */
1978 void /* PRIVATE */
1979 png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
1980 {
1981 #ifdef PNG_USE_LOCAL_ARRAYS
1982 /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
1984 /* start of interlace block */
1985 int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
1987 /* offset to next interlace block */
1988 int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
1989 #endif
1991 png_debug(1, "in png_do_write_interlace\n");
1992 /* we don't have to do anything on the last pass (6) */
1993 #if defined(PNG_USELESS_TESTS_SUPPORTED)
1994 if (row != NULL && row_info != NULL && pass < 6)
1995 #else
1996 if (pass < 6)
1997 #endif
1998 {
1999 /* each pixel depth is handled separately */
2000 switch (row_info->pixel_depth)
2001 {
2002 case 1:
2003 {
2004 png_bytep sp;
2005 png_bytep dp;
2006 int shift;
2007 int d;
2008 int value;
2009 png_uint_32 i;
2010 png_uint_32 row_width = row_info->width;
2012 dp = row;
2013 d = 0;
2014 shift = 7;
2015 for (i = png_pass_start[pass]; i < row_width;
2016 i += png_pass_inc[pass])
2017 {
2018 sp = row + (png_size_t)(i >> 3);
2019 value = (int)(*sp >> (7 - (int)(i & 0x07))) & 0x01;
2020 d |= (value << shift);
2022 if (shift == 0)
2023 {
2024 shift = 7;
2025 *dp++ = (png_byte)d;
2026 d = 0;
2027 }
2028 else
2029 shift--;
2031 }
2032 if (shift != 7)
2033 *dp = (png_byte)d;
2034 break;
2035 }
2036 case 2:
2037 {
2038 png_bytep sp;
2039 png_bytep dp;
2040 int shift;
2041 int d;
2042 int value;
2043 png_uint_32 i;
2044 png_uint_32 row_width = row_info->width;
2046 dp = row;
2047 shift = 6;
2048 d = 0;
2049 for (i = png_pass_start[pass]; i < row_width;
2050 i += png_pass_inc[pass])
2051 {
2052 sp = row + (png_size_t)(i >> 2);
2053 value = (*sp >> ((3 - (int)(i & 0x03)) << 1)) & 0x03;
2054 d |= (value << shift);
2056 if (shift == 0)
2057 {
2058 shift = 6;
2059 *dp++ = (png_byte)d;
2060 d = 0;
2061 }
2062 else
2063 shift -= 2;
2064 }
2065 if (shift != 6)
2066 *dp = (png_byte)d;
2067 break;
2068 }
2069 case 4:
2070 {
2071 png_bytep sp;
2072 png_bytep dp;
2073 int shift;
2074 int d;
2075 int value;
2076 png_uint_32 i;
2077 png_uint_32 row_width = row_info->width;
2079 dp = row;
2080 shift = 4;
2081 d = 0;
2082 for (i = png_pass_start[pass]; i < row_width;
2083 i += png_pass_inc[pass])
2084 {
2085 sp = row + (png_size_t)(i >> 1);
2086 value = (*sp >> ((1 - (int)(i & 0x01)) << 2)) & 0x0f;
2087 d |= (value << shift);
2089 if (shift == 0)
2090 {
2091 shift = 4;
2092 *dp++ = (png_byte)d;
2093 d = 0;
2094 }
2095 else
2096 shift -= 4;
2097 }
2098 if (shift != 4)
2099 *dp = (png_byte)d;
2100 break;
2101 }
2102 default:
2103 {
2104 png_bytep sp;
2105 png_bytep dp;
2106 png_uint_32 i;
2107 png_uint_32 row_width = row_info->width;
2108 png_size_t pixel_bytes;
2110 /* start at the beginning */
2111 dp = row;
2112 /* find out how many bytes each pixel takes up */
2113 pixel_bytes = (row_info->pixel_depth >> 3);
2114 /* loop through the row, only looking at the pixels that
2115 matter */
2116 for (i = png_pass_start[pass]; i < row_width;
2117 i += png_pass_inc[pass])
2118 {
2119 /* find out where the original pixel is */
2120 sp = row + (png_size_t)i * pixel_bytes;
2121 /* move the pixel */
2122 if (dp != sp)
2123 png_memcpy(dp, sp, pixel_bytes);
2124 /* next pixel */
2125 dp += pixel_bytes;
2126 }
2127 break;
2128 }
2129 }
2130 /* set new row width */
2131 row_info->width = (row_info->width +
2132 png_pass_inc[pass] - 1 -
2133 png_pass_start[pass]) /
2134 png_pass_inc[pass];
2135 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
2136 row_info->width);
2137 }
2138 }
2139 #endif
2141 /* This filters the row, chooses which filter to use, if it has not already
2142 * been specified by the application, and then writes the row out with the
2143 * chosen filter.
2144 */
2145 #define PNG_MAXSUM (((png_uint_32)(-1)) >> 1)
2146 #define PNG_HISHIFT 10
2147 #define PNG_LOMASK ((png_uint_32)0xffffL)
2148 #define PNG_HIMASK ((png_uint_32)(~PNG_LOMASK >> PNG_HISHIFT))
2149 void /* PRIVATE */
2150 png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
2151 {
2152 png_bytep best_row;
2153 #ifndef PNG_NO_WRITE_FILTER
2154 png_bytep prev_row, row_buf;
2155 png_uint_32 mins, bpp;
2156 png_byte filter_to_do = png_ptr->do_filter;
2157 png_uint_32 row_bytes = row_info->rowbytes;
2158 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2159 int num_p_filters = (int)png_ptr->num_prev_filters;
2160 #endif
2162 png_debug(1, "in png_write_find_filter\n");
2163 /* find out how many bytes offset each pixel is */
2164 bpp = (row_info->pixel_depth + 7) >> 3;
2166 prev_row = png_ptr->prev_row;
2167 #endif
2168 best_row = png_ptr->row_buf;
2169 #ifndef PNG_NO_WRITE_FILTER
2170 row_buf = best_row;
2171 mins = PNG_MAXSUM;
2173 /* The prediction method we use is to find which method provides the
2174 * smallest value when summing the absolute values of the distances
2175 * from zero, using anything >= 128 as negative numbers. This is known
2176 * as the "minimum sum of absolute differences" heuristic. Other
2177 * heuristics are the "weighted minimum sum of absolute differences"
2178 * (experimental and can in theory improve compression), and the "zlib
2179 * predictive" method (not implemented yet), which does test compressions
2180 * of lines using different filter methods, and then chooses the
2181 * (series of) filter(s) that give minimum compressed data size (VERY
2182 * computationally expensive).
2183 *
2184 * GRR 980525: consider also
2185 * (1) minimum sum of absolute differences from running average (i.e.,
2186 * keep running sum of non-absolute differences & count of bytes)
2187 * [track dispersion, too? restart average if dispersion too large?]
2188 * (1b) minimum sum of absolute differences from sliding average, probably
2189 * with window size <= deflate window (usually 32K)
2190 * (2) minimum sum of squared differences from zero or running average
2191 * (i.e., ~ root-mean-square approach)
2192 */
2195 /* We don't need to test the 'no filter' case if this is the only filter
2196 * that has been chosen, as it doesn't actually do anything to the data.
2197 */
2198 if ((filter_to_do & PNG_FILTER_NONE) &&
2199 filter_to_do != PNG_FILTER_NONE)
2200 {
2201 png_bytep rp;
2202 png_uint_32 sum = 0;
2203 png_uint_32 i;
2204 int v;
2206 for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
2207 {
2208 v = *rp;
2209 sum += (v < 128) ? v : 256 - v;
2210 }
2212 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2213 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2214 {
2215 png_uint_32 sumhi, sumlo;
2216 int j;
2217 sumlo = sum & PNG_LOMASK;
2218 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; /* Gives us some footroom */
2220 /* Reduce the sum if we match any of the previous rows */
2221 for (j = 0; j < num_p_filters; j++)
2222 {
2223 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
2224 {
2225 sumlo = (sumlo * png_ptr->filter_weights[j]) >>
2226 PNG_WEIGHT_SHIFT;
2227 sumhi = (sumhi * png_ptr->filter_weights[j]) >>
2228 PNG_WEIGHT_SHIFT;
2229 }
2230 }
2232 /* Factor in the cost of this filter (this is here for completeness,
2233 * but it makes no sense to have a "cost" for the NONE filter, as
2234 * it has the minimum possible computational cost - none).
2235 */
2236 sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>
2237 PNG_COST_SHIFT;
2238 sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>
2239 PNG_COST_SHIFT;
2241 if (sumhi > PNG_HIMASK)
2242 sum = PNG_MAXSUM;
2243 else
2244 sum = (sumhi << PNG_HISHIFT) + sumlo;
2245 }
2246 #endif
2247 mins = sum;
2248 }
2250 /* sub filter */
2251 if (filter_to_do == PNG_FILTER_SUB)
2252 /* it's the only filter so no testing is needed */
2253 {
2254 png_bytep rp, lp, dp;
2255 png_uint_32 i;
2256 for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
2257 i++, rp++, dp++)
2258 {
2259 *dp = *rp;
2260 }
2261 for (lp = row_buf + 1; i < row_bytes;
2262 i++, rp++, lp++, dp++)
2263 {
2264 *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
2265 }
2266 best_row = png_ptr->sub_row;
2267 }
2269 else if (filter_to_do & PNG_FILTER_SUB)
2270 {
2271 png_bytep rp, dp, lp;
2272 png_uint_32 sum = 0, lmins = mins;
2273 png_uint_32 i;
2274 int v;
2276 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2277 /* We temporarily increase the "minimum sum" by the factor we
2278 * would reduce the sum of this filter, so that we can do the
2279 * early exit comparison without scaling the sum each time.
2280 */
2281 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2282 {
2283 int j;
2284 png_uint_32 lmhi, lmlo;
2285 lmlo = lmins & PNG_LOMASK;
2286 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
2288 for (j = 0; j < num_p_filters; j++)
2289 {
2290 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
2291 {
2292 lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
2293 PNG_WEIGHT_SHIFT;
2294 lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
2295 PNG_WEIGHT_SHIFT;
2296 }
2297 }
2299 lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
2300 PNG_COST_SHIFT;
2301 lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
2302 PNG_COST_SHIFT;
2304 if (lmhi > PNG_HIMASK)
2305 lmins = PNG_MAXSUM;
2306 else
2307 lmins = (lmhi << PNG_HISHIFT) + lmlo;
2308 }
2309 #endif
2311 for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
2312 i++, rp++, dp++)
2313 {
2314 v = *dp = *rp;
2316 sum += (v < 128) ? v : 256 - v;
2317 }
2318 for (lp = row_buf + 1; i < row_bytes;
2319 i++, rp++, lp++, dp++)
2320 {
2321 v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
2323 sum += (v < 128) ? v : 256 - v;
2325 if (sum > lmins) /* We are already worse, don't continue. */
2326 break;
2327 }
2329 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2330 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2331 {
2332 int j;
2333 png_uint_32 sumhi, sumlo;
2334 sumlo = sum & PNG_LOMASK;
2335 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
2337 for (j = 0; j < num_p_filters; j++)
2338 {
2339 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
2340 {
2341 sumlo = (sumlo * png_ptr->inv_filter_weights[j]) >>
2342 PNG_WEIGHT_SHIFT;
2343 sumhi = (sumhi * png_ptr->inv_filter_weights[j]) >>
2344 PNG_WEIGHT_SHIFT;
2345 }
2346 }
2348 sumlo = (sumlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
2349 PNG_COST_SHIFT;
2350 sumhi = (sumhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
2351 PNG_COST_SHIFT;
2353 if (sumhi > PNG_HIMASK)
2354 sum = PNG_MAXSUM;
2355 else
2356 sum = (sumhi << PNG_HISHIFT) + sumlo;
2357 }
2358 #endif
2360 if (sum < mins)
2361 {
2362 mins = sum;
2363 best_row = png_ptr->sub_row;
2364 }
2365 }
2367 /* up filter */
2368 if (filter_to_do == PNG_FILTER_UP)
2369 {
2370 png_bytep rp, dp, pp;
2371 png_uint_32 i;
2373 for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
2374 pp = prev_row + 1; i < row_bytes;
2375 i++, rp++, pp++, dp++)
2376 {
2377 *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
2378 }
2379 best_row = png_ptr->up_row;
2380 }
2382 else if (filter_to_do & PNG_FILTER_UP)
2383 {
2384 png_bytep rp, dp, pp;
2385 png_uint_32 sum = 0, lmins = mins;
2386 png_uint_32 i;
2387 int v;
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 lmhi, lmlo;
2395 lmlo = lmins & PNG_LOMASK;
2396 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
2398 for (j = 0; j < num_p_filters; j++)
2399 {
2400 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
2401 {
2402 lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
2403 PNG_WEIGHT_SHIFT;
2404 lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
2405 PNG_WEIGHT_SHIFT;
2406 }
2407 }
2409 lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
2410 PNG_COST_SHIFT;
2411 lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
2412 PNG_COST_SHIFT;
2414 if (lmhi > PNG_HIMASK)
2415 lmins = PNG_MAXSUM;
2416 else
2417 lmins = (lmhi << PNG_HISHIFT) + lmlo;
2418 }
2419 #endif
2421 for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
2422 pp = prev_row + 1; i < row_bytes; i++)
2423 {
2424 v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
2426 sum += (v < 128) ? v : 256 - v;
2428 if (sum > lmins) /* We are already worse, don't continue. */
2429 break;
2430 }
2432 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2433 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2434 {
2435 int j;
2436 png_uint_32 sumhi, sumlo;
2437 sumlo = sum & PNG_LOMASK;
2438 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
2440 for (j = 0; j < num_p_filters; j++)
2441 {
2442 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
2443 {
2444 sumlo = (sumlo * png_ptr->filter_weights[j]) >>
2445 PNG_WEIGHT_SHIFT;
2446 sumhi = (sumhi * png_ptr->filter_weights[j]) >>
2447 PNG_WEIGHT_SHIFT;
2448 }
2449 }
2451 sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
2452 PNG_COST_SHIFT;
2453 sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
2454 PNG_COST_SHIFT;
2456 if (sumhi > PNG_HIMASK)
2457 sum = PNG_MAXSUM;
2458 else
2459 sum = (sumhi << PNG_HISHIFT) + sumlo;
2460 }
2461 #endif
2463 if (sum < mins)
2464 {
2465 mins = sum;
2466 best_row = png_ptr->up_row;
2467 }
2468 }
2470 /* avg filter */
2471 if (filter_to_do == PNG_FILTER_AVG)
2472 {
2473 png_bytep rp, dp, pp, lp;
2474 png_uint_32 i;
2475 for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
2476 pp = prev_row + 1; i < bpp; i++)
2477 {
2478 *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
2479 }
2480 for (lp = row_buf + 1; i < row_bytes; i++)
2481 {
2482 *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
2483 & 0xff);
2484 }
2485 best_row = png_ptr->avg_row;
2486 }
2488 else if (filter_to_do & PNG_FILTER_AVG)
2489 {
2490 png_bytep rp, dp, pp, lp;
2491 png_uint_32 sum = 0, lmins = mins;
2492 png_uint_32 i;
2493 int v;
2495 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2496 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2497 {
2498 int j;
2499 png_uint_32 lmhi, lmlo;
2500 lmlo = lmins & PNG_LOMASK;
2501 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
2503 for (j = 0; j < num_p_filters; j++)
2504 {
2505 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_AVG)
2506 {
2507 lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
2508 PNG_WEIGHT_SHIFT;
2509 lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
2510 PNG_WEIGHT_SHIFT;
2511 }
2512 }
2514 lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
2515 PNG_COST_SHIFT;
2516 lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
2517 PNG_COST_SHIFT;
2519 if (lmhi > PNG_HIMASK)
2520 lmins = PNG_MAXSUM;
2521 else
2522 lmins = (lmhi << PNG_HISHIFT) + lmlo;
2523 }
2524 #endif
2526 for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
2527 pp = prev_row + 1; i < bpp; i++)
2528 {
2529 v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
2531 sum += (v < 128) ? v : 256 - v;
2532 }
2533 for (lp = row_buf + 1; i < row_bytes; i++)
2534 {
2535 v = *dp++ =
2536 (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) & 0xff);
2538 sum += (v < 128) ? v : 256 - v;
2540 if (sum > lmins) /* We are already worse, don't continue. */
2541 break;
2542 }
2544 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2545 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2546 {
2547 int j;
2548 png_uint_32 sumhi, sumlo;
2549 sumlo = sum & PNG_LOMASK;
2550 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
2552 for (j = 0; j < num_p_filters; j++)
2553 {
2554 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
2555 {
2556 sumlo = (sumlo * png_ptr->filter_weights[j]) >>
2557 PNG_WEIGHT_SHIFT;
2558 sumhi = (sumhi * png_ptr->filter_weights[j]) >>
2559 PNG_WEIGHT_SHIFT;
2560 }
2561 }
2563 sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
2564 PNG_COST_SHIFT;
2565 sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
2566 PNG_COST_SHIFT;
2568 if (sumhi > PNG_HIMASK)
2569 sum = PNG_MAXSUM;
2570 else
2571 sum = (sumhi << PNG_HISHIFT) + sumlo;
2572 }
2573 #endif
2575 if (sum < mins)
2576 {
2577 mins = sum;
2578 best_row = png_ptr->avg_row;
2579 }
2580 }
2582 /* Paeth filter */
2583 if (filter_to_do == PNG_FILTER_PAETH)
2584 {
2585 png_bytep rp, dp, pp, cp, lp;
2586 png_uint_32 i;
2587 for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
2588 pp = prev_row + 1; i < bpp; i++)
2589 {
2590 *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
2591 }
2593 for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
2594 {
2595 int a, b, c, pa, pb, pc, p;
2597 b = *pp++;
2598 c = *cp++;
2599 a = *lp++;
2601 p = b - c;
2602 pc = a - c;
2604 #ifdef PNG_USE_ABS
2605 pa = abs(p);
2606 pb = abs(pc);
2607 pc = abs(p + pc);
2608 #else
2609 pa = p < 0 ? -p : p;
2610 pb = pc < 0 ? -pc : pc;
2611 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
2612 #endif
2614 p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
2616 *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
2617 }
2618 best_row = png_ptr->paeth_row;
2619 }
2621 else if (filter_to_do & PNG_FILTER_PAETH)
2622 {
2623 png_bytep rp, dp, pp, cp, lp;
2624 png_uint_32 sum = 0, lmins = mins;
2625 png_uint_32 i;
2626 int v;
2628 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2629 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2630 {
2631 int j;
2632 png_uint_32 lmhi, lmlo;
2633 lmlo = lmins & PNG_LOMASK;
2634 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
2636 for (j = 0; j < num_p_filters; j++)
2637 {
2638 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
2639 {
2640 lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
2641 PNG_WEIGHT_SHIFT;
2642 lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
2643 PNG_WEIGHT_SHIFT;
2644 }
2645 }
2647 lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>
2648 PNG_COST_SHIFT;
2649 lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>
2650 PNG_COST_SHIFT;
2652 if (lmhi > PNG_HIMASK)
2653 lmins = PNG_MAXSUM;
2654 else
2655 lmins = (lmhi << PNG_HISHIFT) + lmlo;
2656 }
2657 #endif
2659 for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
2660 pp = prev_row + 1; i < bpp; i++)
2661 {
2662 v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
2664 sum += (v < 128) ? v : 256 - v;
2665 }
2667 for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
2668 {
2669 int a, b, c, pa, pb, pc, p;
2671 b = *pp++;
2672 c = *cp++;
2673 a = *lp++;
2675 #ifndef PNG_SLOW_PAETH
2676 p = b - c;
2677 pc = a - c;
2678 #ifdef PNG_USE_ABS
2679 pa = abs(p);
2680 pb = abs(pc);
2681 pc = abs(p + pc);
2682 #else
2683 pa = p < 0 ? -p : p;
2684 pb = pc < 0 ? -pc : pc;
2685 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
2686 #endif
2687 p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
2688 #else /* PNG_SLOW_PAETH */
2689 p = a + b - c;
2690 pa = abs(p - a);
2691 pb = abs(p - b);
2692 pc = abs(p - c);
2693 if (pa <= pb && pa <= pc)
2694 p = a;
2695 else if (pb <= pc)
2696 p = b;
2697 else
2698 p = c;
2699 #endif /* PNG_SLOW_PAETH */
2701 v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
2703 sum += (v < 128) ? v : 256 - v;
2705 if (sum > lmins) /* We are already worse, don't continue. */
2706 break;
2707 }
2709 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2710 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2711 {
2712 int j;
2713 png_uint_32 sumhi, sumlo;
2714 sumlo = sum & PNG_LOMASK;
2715 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
2717 for (j = 0; j < num_p_filters; j++)
2718 {
2719 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
2720 {
2721 sumlo = (sumlo * png_ptr->filter_weights[j]) >>
2722 PNG_WEIGHT_SHIFT;
2723 sumhi = (sumhi * png_ptr->filter_weights[j]) >>
2724 PNG_WEIGHT_SHIFT;
2725 }
2726 }
2728 sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>
2729 PNG_COST_SHIFT;
2730 sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>
2731 PNG_COST_SHIFT;
2733 if (sumhi > PNG_HIMASK)
2734 sum = PNG_MAXSUM;
2735 else
2736 sum = (sumhi << PNG_HISHIFT) + sumlo;
2737 }
2738 #endif
2740 if (sum < mins)
2741 {
2742 best_row = png_ptr->paeth_row;
2743 }
2744 }
2745 #endif /* PNG_NO_WRITE_FILTER */
2746 /* Do the actual writing of the filtered row data from the chosen filter. */
2748 png_write_filtered_row(png_ptr, best_row);
2750 #ifndef PNG_NO_WRITE_FILTER
2751 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2752 /* Save the type of filter we picked this time for future calculations */
2753 if (png_ptr->num_prev_filters > 0)
2754 {
2755 int j;
2756 for (j = 1; j < num_p_filters; j++)
2757 {
2758 png_ptr->prev_filters[j] = png_ptr->prev_filters[j - 1];
2759 }
2760 png_ptr->prev_filters[j] = best_row[0];
2761 }
2762 #endif
2763 #endif /* PNG_NO_WRITE_FILTER */
2764 }
2767 /* Do the actual writing of a previously filtered row. */
2768 void /* PRIVATE */
2769 png_write_filtered_row(png_structp png_ptr, png_bytep filtered_row)
2770 {
2771 png_debug(1, "in png_write_filtered_row\n");
2772 png_debug1(2, "filter = %d\n", filtered_row[0]);
2773 /* set up the zlib input buffer */
2775 png_ptr->zstream.next_in = filtered_row;
2776 png_ptr->zstream.avail_in = (uInt)png_ptr->row_info.rowbytes + 1;
2777 /* repeat until we have compressed all the data */
2778 do
2779 {
2780 int ret; /* return of zlib */
2782 /* compress the data */
2783 ret = deflate(&png_ptr->zstream, Z_NO_FLUSH);
2784 /* check for compression errors */
2785 if (ret != Z_OK)
2786 {
2787 if (png_ptr->zstream.msg != NULL)
2788 png_error(png_ptr, png_ptr->zstream.msg);
2789 else
2790 png_error(png_ptr, "zlib error");
2791 }
2793 /* see if it is time to write another IDAT */
2794 if (!(png_ptr->zstream.avail_out))
2795 {
2796 /* write the IDAT and reset the zlib output buffer */
2797 png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
2798 png_ptr->zstream.next_out = png_ptr->zbuf;
2799 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
2800 }
2801 /* repeat until all data has been compressed */
2802 } while (png_ptr->zstream.avail_in);
2804 /* swap the current and previous rows */
2805 if (png_ptr->prev_row != NULL)
2806 {
2807 png_bytep tptr;
2809 tptr = png_ptr->prev_row;
2810 png_ptr->prev_row = png_ptr->row_buf;
2811 png_ptr->row_buf = tptr;
2812 }
2814 /* finish row - updates counters and flushes zlib if last row */
2815 png_write_finish_row(png_ptr);
2817 #if defined(PNG_WRITE_FLUSH_SUPPORTED)
2818 png_ptr->flush_rows++;
2820 if (png_ptr->flush_dist > 0 &&
2821 png_ptr->flush_rows >= png_ptr->flush_dist)
2822 {
2823 png_write_flush(png_ptr);
2824 }
2825 #endif
2826 }
2827 #endif /* PNG_WRITE_SUPPORTED */