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comparison ext/libpng-1.2.29/pngwutil.c @ 0:4a0efb7baf70

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* Datasets becomes the new trunk and retires after that :-)
author mvbarracuda@33b003aa-7bff-0310-803a-e67f0ece8222
date Sun, 29 Jun 2008 18:44:17 +0000
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-1:000000000000 0:4a0efb7baf70
1
2 /* pngwutil.c - utilities to write a PNG file
3 *
4 * Last changed in libpng 1.2.27 [April 29, 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 /* Write a PNG chunk all at once. The type is an array of ASCII characters
53 * representing the chunk name. The array must be at least 4 bytes in
54 * length, and does not need to be null terminated. To be safe, pass the
55 * pre-defined chunk names here, and if you need a new one, define it
56 * where the others are defined. The length is the length of the data.
57 * All the data must be present. If that is not possible, use the
58 * png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end()
59 * functions instead.
60 */
61 void PNGAPI
62 png_write_chunk(png_structp png_ptr, png_bytep chunk_name,
63 png_bytep data, png_size_t length)
64 {
65 if(png_ptr == NULL) return;
66 png_write_chunk_start(png_ptr, chunk_name, (png_uint_32)length);
67 png_write_chunk_data(png_ptr, data, length);
68 png_write_chunk_end(png_ptr);
69 }
70
71 /* Write the start of a PNG chunk. The type is the chunk type.
72 * The total_length is the sum of the lengths of all the data you will be
73 * passing in png_write_chunk_data().
74 */
75 void PNGAPI
76 png_write_chunk_start(png_structp png_ptr, png_bytep chunk_name,
77 png_uint_32 length)
78 {
79 png_byte buf[4];
80 png_debug2(0, "Writing %s chunk (%lu bytes)\n", chunk_name, length);
81 if(png_ptr == NULL) return;
82
83 /* write the length */
84 png_save_uint_32(buf, length);
85 png_write_data(png_ptr, buf, (png_size_t)4);
86
87 /* write the chunk name */
88 png_write_data(png_ptr, chunk_name, (png_size_t)4);
89 /* reset the crc and run it over the chunk name */
90 png_reset_crc(png_ptr);
91 png_calculate_crc(png_ptr, chunk_name, (png_size_t)4);
92 }
93
94 /* Write the data of a PNG chunk started with png_write_chunk_start().
95 * Note that multiple calls to this function are allowed, and that the
96 * sum of the lengths from these calls *must* add up to the total_length
97 * given to png_write_chunk_start().
98 */
99 void PNGAPI
100 png_write_chunk_data(png_structp png_ptr, png_bytep data, png_size_t length)
101 {
102 /* write the data, and run the CRC over it */
103 if(png_ptr == NULL) return;
104 if (data != NULL && length > 0)
105 {
106 png_calculate_crc(png_ptr, data, length);
107 png_write_data(png_ptr, data, length);
108 }
109 }
110
111 /* Finish a chunk started with png_write_chunk_start(). */
112 void PNGAPI
113 png_write_chunk_end(png_structp png_ptr)
114 {
115 png_byte buf[4];
116
117 if(png_ptr == NULL) return;
118
119 /* write the crc */
120 png_save_uint_32(buf, png_ptr->crc);
121
122 png_write_data(png_ptr, buf, (png_size_t)4);
123 }
124
125 /* Simple function to write the signature. If we have already written
126 * the magic bytes of the signature, or more likely, the PNG stream is
127 * being embedded into another stream and doesn't need its own signature,
128 * we should call png_set_sig_bytes() to tell libpng how many of the
129 * bytes have already been written.
130 */
131 void /* PRIVATE */
132 png_write_sig(png_structp png_ptr)
133 {
134 png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
135 /* write the rest of the 8 byte signature */
136 png_write_data(png_ptr, &png_signature[png_ptr->sig_bytes],
137 (png_size_t)8 - png_ptr->sig_bytes);
138 if(png_ptr->sig_bytes < 3)
139 png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
140 }
141
142 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_iCCP_SUPPORTED)
143 /*
144 * This pair of functions encapsulates the operation of (a) compressing a
145 * text string, and (b) issuing it later as a series of chunk data writes.
146 * The compression_state structure is shared context for these functions
147 * set up by the caller in order to make the whole mess thread-safe.
148 */
149
150 typedef struct
151 {
152 char *input; /* the uncompressed input data */
153 int input_len; /* its length */
154 int num_output_ptr; /* number of output pointers used */
155 int max_output_ptr; /* size of output_ptr */
156 png_charpp output_ptr; /* array of pointers to output */
157 } compression_state;
158
159 /* compress given text into storage in the png_ptr structure */
160 static int /* PRIVATE */
161 png_text_compress(png_structp png_ptr,
162 png_charp text, png_size_t text_len, int compression,
163 compression_state *comp)
164 {
165 int ret;
166
167 comp->num_output_ptr = 0;
168 comp->max_output_ptr = 0;
169 comp->output_ptr = NULL;
170 comp->input = NULL;
171 comp->input_len = 0;
172
173 /* we may just want to pass the text right through */
174 if (compression == PNG_TEXT_COMPRESSION_NONE)
175 {
176 comp->input = text;
177 comp->input_len = text_len;
178 return((int)text_len);
179 }
180
181 if (compression >= PNG_TEXT_COMPRESSION_LAST)
182 {
183 #if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
184 char msg[50];
185 png_snprintf(msg, 50, "Unknown compression type %d", compression);
186 png_warning(png_ptr, msg);
187 #else
188 png_warning(png_ptr, "Unknown compression type");
189 #endif
190 }
191
192 /* We can't write the chunk until we find out how much data we have,
193 * which means we need to run the compressor first and save the
194 * output. This shouldn't be a problem, as the vast majority of
195 * comments should be reasonable, but we will set up an array of
196 * malloc'd pointers to be sure.
197 *
198 * If we knew the application was well behaved, we could simplify this
199 * greatly by assuming we can always malloc an output buffer large
200 * enough to hold the compressed text ((1001 * text_len / 1000) + 12)
201 * and malloc this directly. The only time this would be a bad idea is
202 * if we can't malloc more than 64K and we have 64K of random input
203 * data, or if the input string is incredibly large (although this
204 * wouldn't cause a failure, just a slowdown due to swapping).
205 */
206
207 /* set up the compression buffers */
208 png_ptr->zstream.avail_in = (uInt)text_len;
209 png_ptr->zstream.next_in = (Bytef *)text;
210 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
211 png_ptr->zstream.next_out = (Bytef *)png_ptr->zbuf;
212
213 /* this is the same compression loop as in png_write_row() */
214 do
215 {
216 /* compress the data */
217 ret = deflate(&png_ptr->zstream, Z_NO_FLUSH);
218 if (ret != Z_OK)
219 {
220 /* error */
221 if (png_ptr->zstream.msg != NULL)
222 png_error(png_ptr, png_ptr->zstream.msg);
223 else
224 png_error(png_ptr, "zlib error");
225 }
226 /* check to see if we need more room */
227 if (!(png_ptr->zstream.avail_out))
228 {
229 /* make sure the output array has room */
230 if (comp->num_output_ptr >= comp->max_output_ptr)
231 {
232 int old_max;
233
234 old_max = comp->max_output_ptr;
235 comp->max_output_ptr = comp->num_output_ptr + 4;
236 if (comp->output_ptr != NULL)
237 {
238 png_charpp old_ptr;
239
240 old_ptr = comp->output_ptr;
241 comp->output_ptr = (png_charpp)png_malloc(png_ptr,
242 (png_uint_32)(comp->max_output_ptr *
243 png_sizeof (png_charpp)));
244 png_memcpy(comp->output_ptr, old_ptr, old_max
245 * png_sizeof (png_charp));
246 png_free(png_ptr, old_ptr);
247 }
248 else
249 comp->output_ptr = (png_charpp)png_malloc(png_ptr,
250 (png_uint_32)(comp->max_output_ptr *
251 png_sizeof (png_charp)));
252 }
253
254 /* save the data */
255 comp->output_ptr[comp->num_output_ptr] = (png_charp)png_malloc(png_ptr,
256 (png_uint_32)png_ptr->zbuf_size);
257 png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf,
258 png_ptr->zbuf_size);
259 comp->num_output_ptr++;
260
261 /* and reset the buffer */
262 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
263 png_ptr->zstream.next_out = png_ptr->zbuf;
264 }
265 /* continue until we don't have any more to compress */
266 } while (png_ptr->zstream.avail_in);
267
268 /* finish the compression */
269 do
270 {
271 /* tell zlib we are finished */
272 ret = deflate(&png_ptr->zstream, Z_FINISH);
273
274 if (ret == Z_OK)
275 {
276 /* check to see if we need more room */
277 if (!(png_ptr->zstream.avail_out))
278 {
279 /* check to make sure our output array has room */
280 if (comp->num_output_ptr >= comp->max_output_ptr)
281 {
282 int old_max;
283
284 old_max = comp->max_output_ptr;
285 comp->max_output_ptr = comp->num_output_ptr + 4;
286 if (comp->output_ptr != NULL)
287 {
288 png_charpp old_ptr;
289
290 old_ptr = comp->output_ptr;
291 /* This could be optimized to realloc() */
292 comp->output_ptr = (png_charpp)png_malloc(png_ptr,
293 (png_uint_32)(comp->max_output_ptr *
294 png_sizeof (png_charpp)));
295 png_memcpy(comp->output_ptr, old_ptr,
296 old_max * png_sizeof (png_charp));
297 png_free(png_ptr, old_ptr);
298 }
299 else
300 comp->output_ptr = (png_charpp)png_malloc(png_ptr,
301 (png_uint_32)(comp->max_output_ptr *
302 png_sizeof (png_charp)));
303 }
304
305 /* save off the data */
306 comp->output_ptr[comp->num_output_ptr] =
307 (png_charp)png_malloc(png_ptr, (png_uint_32)png_ptr->zbuf_size);
308 png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf,
309 png_ptr->zbuf_size);
310 comp->num_output_ptr++;
311
312 /* and reset the buffer pointers */
313 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
314 png_ptr->zstream.next_out = png_ptr->zbuf;
315 }
316 }
317 else if (ret != Z_STREAM_END)
318 {
319 /* we got an error */
320 if (png_ptr->zstream.msg != NULL)
321 png_error(png_ptr, png_ptr->zstream.msg);
322 else
323 png_error(png_ptr, "zlib error");
324 }
325 } while (ret != Z_STREAM_END);
326
327 /* text length is number of buffers plus last buffer */
328 text_len = png_ptr->zbuf_size * comp->num_output_ptr;
329 if (png_ptr->zstream.avail_out < png_ptr->zbuf_size)
330 text_len += png_ptr->zbuf_size - (png_size_t)png_ptr->zstream.avail_out;
331
332 return((int)text_len);
333 }
334
335 /* ship the compressed text out via chunk writes */
336 static void /* PRIVATE */
337 png_write_compressed_data_out(png_structp png_ptr, compression_state *comp)
338 {
339 int i;
340
341 /* handle the no-compression case */
342 if (comp->input)
343 {
344 png_write_chunk_data(png_ptr, (png_bytep)comp->input,
345 (png_size_t)comp->input_len);
346 return;
347 }
348
349 /* write saved output buffers, if any */
350 for (i = 0; i < comp->num_output_ptr; i++)
351 {
352 png_write_chunk_data(png_ptr,(png_bytep)comp->output_ptr[i],
353 png_ptr->zbuf_size);
354 png_free(png_ptr, comp->output_ptr[i]);
355 comp->output_ptr[i]=NULL;
356 }
357 if (comp->max_output_ptr != 0)
358 png_free(png_ptr, comp->output_ptr);
359 comp->output_ptr=NULL;
360 /* write anything left in zbuf */
361 if (png_ptr->zstream.avail_out < (png_uint_32)png_ptr->zbuf_size)
362 png_write_chunk_data(png_ptr, png_ptr->zbuf,
363 png_ptr->zbuf_size - png_ptr->zstream.avail_out);
364
365 /* reset zlib for another zTXt/iTXt or image data */
366 deflateReset(&png_ptr->zstream);
367 png_ptr->zstream.data_type = Z_BINARY;
368 }
369 #endif
370
371 /* Write the IHDR chunk, and update the png_struct with the necessary
372 * information. Note that the rest of this code depends upon this
373 * information being correct.
374 */
375 void /* PRIVATE */
376 png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height,
377 int bit_depth, int color_type, int compression_type, int filter_type,
378 int interlace_type)
379 {
380 #ifdef PNG_USE_LOCAL_ARRAYS
381 PNG_IHDR;
382 #endif
383 int ret;
384
385 png_byte buf[13]; /* buffer to store the IHDR info */
386
387 png_debug(1, "in png_write_IHDR\n");
388 /* Check that we have valid input data from the application info */
389 switch (color_type)
390 {
391 case PNG_COLOR_TYPE_GRAY:
392 switch (bit_depth)
393 {
394 case 1:
395 case 2:
396 case 4:
397 case 8:
398 case 16: png_ptr->channels = 1; break;
399 default: png_error(png_ptr,"Invalid bit depth for grayscale image");
400 }
401 break;
402 case PNG_COLOR_TYPE_RGB:
403 if (bit_depth != 8 && bit_depth != 16)
404 png_error(png_ptr, "Invalid bit depth for RGB image");
405 png_ptr->channels = 3;
406 break;
407 case PNG_COLOR_TYPE_PALETTE:
408 switch (bit_depth)
409 {
410 case 1:
411 case 2:
412 case 4:
413 case 8: png_ptr->channels = 1; break;
414 default: png_error(png_ptr, "Invalid bit depth for paletted image");
415 }
416 break;
417 case PNG_COLOR_TYPE_GRAY_ALPHA:
418 if (bit_depth != 8 && bit_depth != 16)
419 png_error(png_ptr, "Invalid bit depth for grayscale+alpha image");
420 png_ptr->channels = 2;
421 break;
422 case PNG_COLOR_TYPE_RGB_ALPHA:
423 if (bit_depth != 8 && bit_depth != 16)
424 png_error(png_ptr, "Invalid bit depth for RGBA image");
425 png_ptr->channels = 4;
426 break;
427 default:
428 png_error(png_ptr, "Invalid image color type specified");
429 }
430
431 if (compression_type != PNG_COMPRESSION_TYPE_BASE)
432 {
433 png_warning(png_ptr, "Invalid compression type specified");
434 compression_type = PNG_COMPRESSION_TYPE_BASE;
435 }
436
437 /* Write filter_method 64 (intrapixel differencing) only if
438 * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
439 * 2. Libpng did not write a PNG signature (this filter_method is only
440 * used in PNG datastreams that are embedded in MNG datastreams) and
441 * 3. The application called png_permit_mng_features with a mask that
442 * included PNG_FLAG_MNG_FILTER_64 and
443 * 4. The filter_method is 64 and
444 * 5. The color_type is RGB or RGBA
445 */
446 if (
447 #if defined(PNG_MNG_FEATURES_SUPPORTED)
448 !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
449 ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) &&
450 (color_type == PNG_COLOR_TYPE_RGB ||
451 color_type == PNG_COLOR_TYPE_RGB_ALPHA) &&
452 (filter_type == PNG_INTRAPIXEL_DIFFERENCING)) &&
453 #endif
454 filter_type != PNG_FILTER_TYPE_BASE)
455 {
456 png_warning(png_ptr, "Invalid filter type specified");
457 filter_type = PNG_FILTER_TYPE_BASE;
458 }
459
460 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
461 if (interlace_type != PNG_INTERLACE_NONE &&
462 interlace_type != PNG_INTERLACE_ADAM7)
463 {
464 png_warning(png_ptr, "Invalid interlace type specified");
465 interlace_type = PNG_INTERLACE_ADAM7;
466 }
467 #else
468 interlace_type=PNG_INTERLACE_NONE;
469 #endif
470
471 /* save off the relevent information */
472 png_ptr->bit_depth = (png_byte)bit_depth;
473 png_ptr->color_type = (png_byte)color_type;
474 png_ptr->interlaced = (png_byte)interlace_type;
475 #if defined(PNG_MNG_FEATURES_SUPPORTED)
476 png_ptr->filter_type = (png_byte)filter_type;
477 #endif
478 png_ptr->compression_type = (png_byte)compression_type;
479 png_ptr->width = width;
480 png_ptr->height = height;
481
482 png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels);
483 png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, width);
484 /* set the usr info, so any transformations can modify it */
485 png_ptr->usr_width = png_ptr->width;
486 png_ptr->usr_bit_depth = png_ptr->bit_depth;
487 png_ptr->usr_channels = png_ptr->channels;
488
489 /* pack the header information into the buffer */
490 png_save_uint_32(buf, width);
491 png_save_uint_32(buf + 4, height);
492 buf[8] = (png_byte)bit_depth;
493 buf[9] = (png_byte)color_type;
494 buf[10] = (png_byte)compression_type;
495 buf[11] = (png_byte)filter_type;
496 buf[12] = (png_byte)interlace_type;
497
498 /* write the chunk */
499 png_write_chunk(png_ptr, png_IHDR, buf, (png_size_t)13);
500
501 /* initialize zlib with PNG info */
502 png_ptr->zstream.zalloc = png_zalloc;
503 png_ptr->zstream.zfree = png_zfree;
504 png_ptr->zstream.opaque = (voidpf)png_ptr;
505 if (!(png_ptr->do_filter))
506 {
507 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||
508 png_ptr->bit_depth < 8)
509 png_ptr->do_filter = PNG_FILTER_NONE;
510 else
511 png_ptr->do_filter = PNG_ALL_FILTERS;
512 }
513 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY))
514 {
515 if (png_ptr->do_filter != PNG_FILTER_NONE)
516 png_ptr->zlib_strategy = Z_FILTERED;
517 else
518 png_ptr->zlib_strategy = Z_DEFAULT_STRATEGY;
519 }
520 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_LEVEL))
521 png_ptr->zlib_level = Z_DEFAULT_COMPRESSION;
522 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL))
523 png_ptr->zlib_mem_level = 8;
524 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS))
525 png_ptr->zlib_window_bits = 15;
526 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_METHOD))
527 png_ptr->zlib_method = 8;
528 ret = deflateInit2(&png_ptr->zstream, png_ptr->zlib_level,
529 png_ptr->zlib_method, png_ptr->zlib_window_bits,
530 png_ptr->zlib_mem_level, png_ptr->zlib_strategy);
531 if (ret != Z_OK)
532 {
533 if (ret == Z_VERSION_ERROR) png_error(png_ptr,
534 "zlib failed to initialize compressor -- version error");
535 if (ret == Z_STREAM_ERROR) png_error(png_ptr,
536 "zlib failed to initialize compressor -- stream error");
537 if (ret == Z_MEM_ERROR) png_error(png_ptr,
538 "zlib failed to initialize compressor -- mem error");
539 png_error(png_ptr, "zlib failed to initialize compressor");
540 }
541 png_ptr->zstream.next_out = png_ptr->zbuf;
542 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
543 /* libpng is not interested in zstream.data_type */
544 /* set it to a predefined value, to avoid its evaluation inside zlib */
545 png_ptr->zstream.data_type = Z_BINARY;
546
547 png_ptr->mode = PNG_HAVE_IHDR;
548 }
549
550 /* write the palette. We are careful not to trust png_color to be in the
551 * correct order for PNG, so people can redefine it to any convenient
552 * structure.
553 */
554 void /* PRIVATE */
555 png_write_PLTE(png_structp png_ptr, png_colorp palette, png_uint_32 num_pal)
556 {
557 #ifdef PNG_USE_LOCAL_ARRAYS
558 PNG_PLTE;
559 #endif
560 png_uint_32 i;
561 png_colorp pal_ptr;
562 png_byte buf[3];
563
564 png_debug(1, "in png_write_PLTE\n");
565 if ((
566 #if defined(PNG_MNG_FEATURES_SUPPORTED)
567 !(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) &&
568 #endif
569 num_pal == 0) || num_pal > 256)
570 {
571 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
572 {
573 png_error(png_ptr, "Invalid number of colors in palette");
574 }
575 else
576 {
577 png_warning(png_ptr, "Invalid number of colors in palette");
578 return;
579 }
580 }
581
582 if (!(png_ptr->color_type&PNG_COLOR_MASK_COLOR))
583 {
584 png_warning(png_ptr,
585 "Ignoring request to write a PLTE chunk in grayscale PNG");
586 return;
587 }
588
589 png_ptr->num_palette = (png_uint_16)num_pal;
590 png_debug1(3, "num_palette = %d\n", png_ptr->num_palette);
591
592 png_write_chunk_start(png_ptr, png_PLTE, num_pal * 3);
593 #ifndef PNG_NO_POINTER_INDEXING
594 for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++)
595 {
596 buf[0] = pal_ptr->red;
597 buf[1] = pal_ptr->green;
598 buf[2] = pal_ptr->blue;
599 png_write_chunk_data(png_ptr, buf, (png_size_t)3);
600 }
601 #else
602 /* This is a little slower but some buggy compilers need to do this instead */
603 pal_ptr=palette;
604 for (i = 0; i < num_pal; i++)
605 {
606 buf[0] = pal_ptr[i].red;
607 buf[1] = pal_ptr[i].green;
608 buf[2] = pal_ptr[i].blue;
609 png_write_chunk_data(png_ptr, buf, (png_size_t)3);
610 }
611 #endif
612 png_write_chunk_end(png_ptr);
613 png_ptr->mode |= PNG_HAVE_PLTE;
614 }
615
616 /* write an IDAT chunk */
617 void /* PRIVATE */
618 png_write_IDAT(png_structp png_ptr, png_bytep data, png_size_t length)
619 {
620 #ifdef PNG_USE_LOCAL_ARRAYS
621 PNG_IDAT;
622 #endif
623 png_debug(1, "in png_write_IDAT\n");
624
625 /* Optimize the CMF field in the zlib stream. */
626 /* This hack of the zlib stream is compliant to the stream specification. */
627 if (!(png_ptr->mode & PNG_HAVE_IDAT) &&
628 png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
629 {
630 unsigned int z_cmf = data[0]; /* zlib compression method and flags */
631 if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70)
632 {
633 /* Avoid memory underflows and multiplication overflows. */
634 /* The conditions below are practically always satisfied;
635 however, they still must be checked. */
636 if (length >= 2 &&
637 png_ptr->height < 16384 && png_ptr->width < 16384)
638 {
639 png_uint_32 uncompressed_idat_size = png_ptr->height *
640 ((png_ptr->width *
641 png_ptr->channels * png_ptr->bit_depth + 15) >> 3);
642 unsigned int z_cinfo = z_cmf >> 4;
643 unsigned int half_z_window_size = 1 << (z_cinfo + 7);
644 while (uncompressed_idat_size <= half_z_window_size &&
645 half_z_window_size >= 256)
646 {
647 z_cinfo--;
648 half_z_window_size >>= 1;
649 }
650 z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4);
651 if (data[0] != (png_byte)z_cmf)
652 {
653 data[0] = (png_byte)z_cmf;
654 data[1] &= 0xe0;
655 data[1] += (png_byte)(0x1f - ((z_cmf << 8) + data[1]) % 0x1f);
656 }
657 }
658 }
659 else
660 png_error(png_ptr,
661 "Invalid zlib compression method or flags in IDAT");
662 }
663
664 png_write_chunk(png_ptr, png_IDAT, data, length);
665 png_ptr->mode |= PNG_HAVE_IDAT;
666 }
667
668 /* write an IEND chunk */
669 void /* PRIVATE */
670 png_write_IEND(png_structp png_ptr)
671 {
672 #ifdef PNG_USE_LOCAL_ARRAYS
673 PNG_IEND;
674 #endif
675 png_debug(1, "in png_write_IEND\n");
676 png_write_chunk(png_ptr, png_IEND, png_bytep_NULL,
677 (png_size_t)0);
678 png_ptr->mode |= PNG_HAVE_IEND;
679 }
680
681 #if defined(PNG_WRITE_gAMA_SUPPORTED)
682 /* write a gAMA chunk */
683 #ifdef PNG_FLOATING_POINT_SUPPORTED
684 void /* PRIVATE */
685 png_write_gAMA(png_structp png_ptr, double file_gamma)
686 {
687 #ifdef PNG_USE_LOCAL_ARRAYS
688 PNG_gAMA;
689 #endif
690 png_uint_32 igamma;
691 png_byte buf[4];
692
693 png_debug(1, "in png_write_gAMA\n");
694 /* file_gamma is saved in 1/100,000ths */
695 igamma = (png_uint_32)(file_gamma * 100000.0 + 0.5);
696 png_save_uint_32(buf, igamma);
697 png_write_chunk(png_ptr, png_gAMA, buf, (png_size_t)4);
698 }
699 #endif
700 #ifdef PNG_FIXED_POINT_SUPPORTED
701 void /* PRIVATE */
702 png_write_gAMA_fixed(png_structp png_ptr, png_fixed_point file_gamma)
703 {
704 #ifdef PNG_USE_LOCAL_ARRAYS
705 PNG_gAMA;
706 #endif
707 png_byte buf[4];
708
709 png_debug(1, "in png_write_gAMA\n");
710 /* file_gamma is saved in 1/100,000ths */
711 png_save_uint_32(buf, (png_uint_32)file_gamma);
712 png_write_chunk(png_ptr, png_gAMA, buf, (png_size_t)4);
713 }
714 #endif
715 #endif
716
717 #if defined(PNG_WRITE_sRGB_SUPPORTED)
718 /* write a sRGB chunk */
719 void /* PRIVATE */
720 png_write_sRGB(png_structp png_ptr, int srgb_intent)
721 {
722 #ifdef PNG_USE_LOCAL_ARRAYS
723 PNG_sRGB;
724 #endif
725 png_byte buf[1];
726
727 png_debug(1, "in png_write_sRGB\n");
728 if(srgb_intent >= PNG_sRGB_INTENT_LAST)
729 png_warning(png_ptr,
730 "Invalid sRGB rendering intent specified");
731 buf[0]=(png_byte)srgb_intent;
732 png_write_chunk(png_ptr, png_sRGB, buf, (png_size_t)1);
733 }
734 #endif
735
736 #if defined(PNG_WRITE_iCCP_SUPPORTED)
737 /* write an iCCP chunk */
738 void /* PRIVATE */
739 png_write_iCCP(png_structp png_ptr, png_charp name, int compression_type,
740 png_charp profile, int profile_len)
741 {
742 #ifdef PNG_USE_LOCAL_ARRAYS
743 PNG_iCCP;
744 #endif
745 png_size_t name_len;
746 png_charp new_name;
747 compression_state comp;
748 int embedded_profile_len = 0;
749
750 png_debug(1, "in png_write_iCCP\n");
751
752 comp.num_output_ptr = 0;
753 comp.max_output_ptr = 0;
754 comp.output_ptr = NULL;
755 comp.input = NULL;
756 comp.input_len = 0;
757
758 if (name == NULL || (name_len = png_check_keyword(png_ptr, name,
759 &new_name)) == 0)
760 {
761 png_warning(png_ptr, "Empty keyword in iCCP chunk");
762 return;
763 }
764
765 if (compression_type != PNG_COMPRESSION_TYPE_BASE)
766 png_warning(png_ptr, "Unknown compression type in iCCP chunk");
767
768 if (profile == NULL)
769 profile_len = 0;
770
771 if (profile_len > 3)
772 embedded_profile_len =
773 ((*( (png_bytep)profile ))<<24) |
774 ((*( (png_bytep)profile+1))<<16) |
775 ((*( (png_bytep)profile+2))<< 8) |
776 ((*( (png_bytep)profile+3)) );
777
778 if (profile_len < embedded_profile_len)
779 {
780 png_warning(png_ptr,
781 "Embedded profile length too large in iCCP chunk");
782 return;
783 }
784
785 if (profile_len > embedded_profile_len)
786 {
787 png_warning(png_ptr,
788 "Truncating profile to actual length in iCCP chunk");
789 profile_len = embedded_profile_len;
790 }
791
792 if (profile_len)
793 profile_len = png_text_compress(png_ptr, profile, (png_size_t)profile_len,
794 PNG_COMPRESSION_TYPE_BASE, &comp);
795
796 /* make sure we include the NULL after the name and the compression type */
797 png_write_chunk_start(png_ptr, png_iCCP,
798 (png_uint_32)name_len+profile_len+2);
799 new_name[name_len+1]=0x00;
800 png_write_chunk_data(png_ptr, (png_bytep)new_name, name_len + 2);
801
802 if (profile_len)
803 png_write_compressed_data_out(png_ptr, &comp);
804
805 png_write_chunk_end(png_ptr);
806 png_free(png_ptr, new_name);
807 }
808 #endif
809
810 #if defined(PNG_WRITE_sPLT_SUPPORTED)
811 /* write a sPLT chunk */
812 void /* PRIVATE */
813 png_write_sPLT(png_structp png_ptr, png_sPLT_tp spalette)
814 {
815 #ifdef PNG_USE_LOCAL_ARRAYS
816 PNG_sPLT;
817 #endif
818 png_size_t name_len;
819 png_charp new_name;
820 png_byte entrybuf[10];
821 int entry_size = (spalette->depth == 8 ? 6 : 10);
822 int palette_size = entry_size * spalette->nentries;
823 png_sPLT_entryp ep;
824 #ifdef PNG_NO_POINTER_INDEXING
825 int i;
826 #endif
827
828 png_debug(1, "in png_write_sPLT\n");
829 if (spalette->name == NULL || (name_len = png_check_keyword(png_ptr,
830 spalette->name, &new_name))==0)
831 {
832 png_warning(png_ptr, "Empty keyword in sPLT chunk");
833 return;
834 }
835
836 /* make sure we include the NULL after the name */
837 png_write_chunk_start(png_ptr, png_sPLT,
838 (png_uint_32)(name_len + 2 + palette_size));
839 png_write_chunk_data(png_ptr, (png_bytep)new_name, name_len + 1);
840 png_write_chunk_data(png_ptr, (png_bytep)&spalette->depth, 1);
841
842 /* loop through each palette entry, writing appropriately */
843 #ifndef PNG_NO_POINTER_INDEXING
844 for (ep = spalette->entries; ep<spalette->entries+spalette->nentries; ep++)
845 {
846 if (spalette->depth == 8)
847 {
848 entrybuf[0] = (png_byte)ep->red;
849 entrybuf[1] = (png_byte)ep->green;
850 entrybuf[2] = (png_byte)ep->blue;
851 entrybuf[3] = (png_byte)ep->alpha;
852 png_save_uint_16(entrybuf + 4, ep->frequency);
853 }
854 else
855 {
856 png_save_uint_16(entrybuf + 0, ep->red);
857 png_save_uint_16(entrybuf + 2, ep->green);
858 png_save_uint_16(entrybuf + 4, ep->blue);
859 png_save_uint_16(entrybuf + 6, ep->alpha);
860 png_save_uint_16(entrybuf + 8, ep->frequency);
861 }
862 png_write_chunk_data(png_ptr, entrybuf, (png_size_t)entry_size);
863 }
864 #else
865 ep=spalette->entries;
866 for (i=0; i>spalette->nentries; i++)
867 {
868 if (spalette->depth == 8)
869 {
870 entrybuf[0] = (png_byte)ep[i].red;
871 entrybuf[1] = (png_byte)ep[i].green;
872 entrybuf[2] = (png_byte)ep[i].blue;
873 entrybuf[3] = (png_byte)ep[i].alpha;
874 png_save_uint_16(entrybuf + 4, ep[i].frequency);
875 }
876 else
877 {
878 png_save_uint_16(entrybuf + 0, ep[i].red);
879 png_save_uint_16(entrybuf + 2, ep[i].green);
880 png_save_uint_16(entrybuf + 4, ep[i].blue);
881 png_save_uint_16(entrybuf + 6, ep[i].alpha);
882 png_save_uint_16(entrybuf + 8, ep[i].frequency);
883 }
884 png_write_chunk_data(png_ptr, entrybuf, entry_size);
885 }
886 #endif
887
888 png_write_chunk_end(png_ptr);
889 png_free(png_ptr, new_name);
890 }
891 #endif
892
893 #if defined(PNG_WRITE_sBIT_SUPPORTED)
894 /* write the sBIT chunk */
895 void /* PRIVATE */
896 png_write_sBIT(png_structp png_ptr, png_color_8p sbit, int color_type)
897 {
898 #ifdef PNG_USE_LOCAL_ARRAYS
899 PNG_sBIT;
900 #endif
901 png_byte buf[4];
902 png_size_t size;
903
904 png_debug(1, "in png_write_sBIT\n");
905 /* make sure we don't depend upon the order of PNG_COLOR_8 */
906 if (color_type & PNG_COLOR_MASK_COLOR)
907 {
908 png_byte maxbits;
909
910 maxbits = (png_byte)(color_type==PNG_COLOR_TYPE_PALETTE ? 8 :
911 png_ptr->usr_bit_depth);
912 if (sbit->red == 0 || sbit->red > maxbits ||
913 sbit->green == 0 || sbit->green > maxbits ||
914 sbit->blue == 0 || sbit->blue > maxbits)
915 {
916 png_warning(png_ptr, "Invalid sBIT depth specified");
917 return;
918 }
919 buf[0] = sbit->red;
920 buf[1] = sbit->green;
921 buf[2] = sbit->blue;
922 size = 3;
923 }
924 else
925 {
926 if (sbit->gray == 0 || sbit->gray > png_ptr->usr_bit_depth)
927 {
928 png_warning(png_ptr, "Invalid sBIT depth specified");
929 return;
930 }
931 buf[0] = sbit->gray;
932 size = 1;
933 }
934
935 if (color_type & PNG_COLOR_MASK_ALPHA)
936 {
937 if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth)
938 {
939 png_warning(png_ptr, "Invalid sBIT depth specified");
940 return;
941 }
942 buf[size++] = sbit->alpha;
943 }
944
945 png_write_chunk(png_ptr, png_sBIT, buf, size);
946 }
947 #endif
948
949 #if defined(PNG_WRITE_cHRM_SUPPORTED)
950 /* write the cHRM chunk */
951 #ifdef PNG_FLOATING_POINT_SUPPORTED
952 void /* PRIVATE */
953 png_write_cHRM(png_structp png_ptr, double white_x, double white_y,
954 double red_x, double red_y, double green_x, double green_y,
955 double blue_x, double blue_y)
956 {
957 #ifdef PNG_USE_LOCAL_ARRAYS
958 PNG_cHRM;
959 #endif
960 png_byte buf[32];
961 png_uint_32 itemp;
962
963 png_debug(1, "in png_write_cHRM\n");
964 /* each value is saved in 1/100,000ths */
965 if (white_x < 0 || white_x > 0.8 || white_y < 0 || white_y > 0.8 ||
966 white_x + white_y > 1.0)
967 {
968 png_warning(png_ptr, "Invalid cHRM white point specified");
969 #if !defined(PNG_NO_CONSOLE_IO)
970 fprintf(stderr,"white_x=%f, white_y=%f\n",white_x, white_y);
971 #endif
972 return;
973 }
974 itemp = (png_uint_32)(white_x * 100000.0 + 0.5);
975 png_save_uint_32(buf, itemp);
976 itemp = (png_uint_32)(white_y * 100000.0 + 0.5);
977 png_save_uint_32(buf + 4, itemp);
978
979 if (red_x < 0 || red_y < 0 || red_x + red_y > 1.0)
980 {
981 png_warning(png_ptr, "Invalid cHRM red point specified");
982 return;
983 }
984 itemp = (png_uint_32)(red_x * 100000.0 + 0.5);
985 png_save_uint_32(buf + 8, itemp);
986 itemp = (png_uint_32)(red_y * 100000.0 + 0.5);
987 png_save_uint_32(buf + 12, itemp);
988
989 if (green_x < 0 || green_y < 0 || green_x + green_y > 1.0)
990 {
991 png_warning(png_ptr, "Invalid cHRM green point specified");
992 return;
993 }
994 itemp = (png_uint_32)(green_x * 100000.0 + 0.5);
995 png_save_uint_32(buf + 16, itemp);
996 itemp = (png_uint_32)(green_y * 100000.0 + 0.5);
997 png_save_uint_32(buf + 20, itemp);
998
999 if (blue_x < 0 || blue_y < 0 || blue_x + blue_y > 1.0)
1000 {
1001 png_warning(png_ptr, "Invalid cHRM blue point specified");
1002 return;
1003 }
1004 itemp = (png_uint_32)(blue_x * 100000.0 + 0.5);
1005 png_save_uint_32(buf + 24, itemp);
1006 itemp = (png_uint_32)(blue_y * 100000.0 + 0.5);
1007 png_save_uint_32(buf + 28, itemp);
1008
1009 png_write_chunk(png_ptr, png_cHRM, buf, (png_size_t)32);
1010 }
1011 #endif
1012 #ifdef PNG_FIXED_POINT_SUPPORTED
1013 void /* PRIVATE */
1014 png_write_cHRM_fixed(png_structp png_ptr, png_fixed_point white_x,
1015 png_fixed_point white_y, png_fixed_point red_x, png_fixed_point red_y,
1016 png_fixed_point green_x, png_fixed_point green_y, png_fixed_point blue_x,
1017 png_fixed_point blue_y)
1018 {
1019 #ifdef PNG_USE_LOCAL_ARRAYS
1020 PNG_cHRM;
1021 #endif
1022 png_byte buf[32];
1023
1024 png_debug(1, "in png_write_cHRM\n");
1025 /* each value is saved in 1/100,000ths */
1026 if (white_x > 80000L || white_y > 80000L || white_x + white_y > 100000L)
1027 {
1028 png_warning(png_ptr, "Invalid fixed cHRM white point specified");
1029 #if !defined(PNG_NO_CONSOLE_IO)
1030 fprintf(stderr,"white_x=%ld, white_y=%ld\n",white_x, white_y);
1031 #endif
1032 return;
1033 }
1034 png_save_uint_32(buf, (png_uint_32)white_x);
1035 png_save_uint_32(buf + 4, (png_uint_32)white_y);
1036
1037 if (red_x + red_y > 100000L)
1038 {
1039 png_warning(png_ptr, "Invalid cHRM fixed red point specified");
1040 return;
1041 }
1042 png_save_uint_32(buf + 8, (png_uint_32)red_x);
1043 png_save_uint_32(buf + 12, (png_uint_32)red_y);
1044
1045 if (green_x + green_y > 100000L)
1046 {
1047 png_warning(png_ptr, "Invalid fixed cHRM green point specified");
1048 return;
1049 }
1050 png_save_uint_32(buf + 16, (png_uint_32)green_x);
1051 png_save_uint_32(buf + 20, (png_uint_32)green_y);
1052
1053 if (blue_x + blue_y > 100000L)
1054 {
1055 png_warning(png_ptr, "Invalid fixed cHRM blue point specified");
1056 return;
1057 }
1058 png_save_uint_32(buf + 24, (png_uint_32)blue_x);
1059 png_save_uint_32(buf + 28, (png_uint_32)blue_y);
1060
1061 png_write_chunk(png_ptr, png_cHRM, buf, (png_size_t)32);
1062 }
1063 #endif
1064 #endif
1065
1066 #if defined(PNG_WRITE_tRNS_SUPPORTED)
1067 /* write the tRNS chunk */
1068 void /* PRIVATE */
1069 png_write_tRNS(png_structp png_ptr, png_bytep trans, png_color_16p tran,
1070 int num_trans, int color_type)
1071 {
1072 #ifdef PNG_USE_LOCAL_ARRAYS
1073 PNG_tRNS;
1074 #endif
1075 png_byte buf[6];
1076
1077 png_debug(1, "in png_write_tRNS\n");
1078 if (color_type == PNG_COLOR_TYPE_PALETTE)
1079 {
1080 if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette)
1081 {
1082 png_warning(png_ptr,"Invalid number of transparent colors specified");
1083 return;
1084 }
1085 /* write the chunk out as it is */
1086 png_write_chunk(png_ptr, png_tRNS, trans, (png_size_t)num_trans);
1087 }
1088 else if (color_type == PNG_COLOR_TYPE_GRAY)
1089 {
1090 /* one 16 bit value */
1091 if(tran->gray >= (1 << png_ptr->bit_depth))
1092 {
1093 png_warning(png_ptr,
1094 "Ignoring attempt to write tRNS chunk out-of-range for bit_depth");
1095 return;
1096 }
1097 png_save_uint_16(buf, tran->gray);
1098 png_write_chunk(png_ptr, png_tRNS, buf, (png_size_t)2);
1099 }
1100 else if (color_type == PNG_COLOR_TYPE_RGB)
1101 {
1102 /* three 16 bit values */
1103 png_save_uint_16(buf, tran->red);
1104 png_save_uint_16(buf + 2, tran->green);
1105 png_save_uint_16(buf + 4, tran->blue);
1106 if(png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
1107 {
1108 png_warning(png_ptr,
1109 "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8");
1110 return;
1111 }
1112 png_write_chunk(png_ptr, png_tRNS, buf, (png_size_t)6);
1113 }
1114 else
1115 {
1116 png_warning(png_ptr, "Can't write tRNS with an alpha channel");
1117 }
1118 }
1119 #endif
1120
1121 #if defined(PNG_WRITE_bKGD_SUPPORTED)
1122 /* write the background chunk */
1123 void /* PRIVATE */
1124 png_write_bKGD(png_structp png_ptr, png_color_16p back, int color_type)
1125 {
1126 #ifdef PNG_USE_LOCAL_ARRAYS
1127 PNG_bKGD;
1128 #endif
1129 png_byte buf[6];
1130
1131 png_debug(1, "in png_write_bKGD\n");
1132 if (color_type == PNG_COLOR_TYPE_PALETTE)
1133 {
1134 if (
1135 #if defined(PNG_MNG_FEATURES_SUPPORTED)
1136 (png_ptr->num_palette ||
1137 (!(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE))) &&
1138 #endif
1139 back->index > png_ptr->num_palette)
1140 {
1141 png_warning(png_ptr, "Invalid background palette index");
1142 return;
1143 }
1144 buf[0] = back->index;
1145 png_write_chunk(png_ptr, png_bKGD, buf, (png_size_t)1);
1146 }
1147 else if (color_type & PNG_COLOR_MASK_COLOR)
1148 {
1149 png_save_uint_16(buf, back->red);
1150 png_save_uint_16(buf + 2, back->green);
1151 png_save_uint_16(buf + 4, back->blue);
1152 if(png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
1153 {
1154 png_warning(png_ptr,
1155 "Ignoring attempt to write 16-bit bKGD chunk when bit_depth is 8");
1156 return;
1157 }
1158 png_write_chunk(png_ptr, png_bKGD, buf, (png_size_t)6);
1159 }
1160 else
1161 {
1162 if(back->gray >= (1 << png_ptr->bit_depth))
1163 {
1164 png_warning(png_ptr,
1165 "Ignoring attempt to write bKGD chunk out-of-range for bit_depth");
1166 return;
1167 }
1168 png_save_uint_16(buf, back->gray);
1169 png_write_chunk(png_ptr, png_bKGD, buf, (png_size_t)2);
1170 }
1171 }
1172 #endif
1173
1174 #if defined(PNG_WRITE_hIST_SUPPORTED)
1175 /* write the histogram */
1176 void /* PRIVATE */
1177 png_write_hIST(png_structp png_ptr, png_uint_16p hist, int num_hist)
1178 {
1179 #ifdef PNG_USE_LOCAL_ARRAYS
1180 PNG_hIST;
1181 #endif
1182 int i;
1183 png_byte buf[3];
1184
1185 png_debug(1, "in png_write_hIST\n");
1186 if (num_hist > (int)png_ptr->num_palette)
1187 {
1188 png_debug2(3, "num_hist = %d, num_palette = %d\n", num_hist,
1189 png_ptr->num_palette);
1190 png_warning(png_ptr, "Invalid number of histogram entries specified");
1191 return;
1192 }
1193
1194 png_write_chunk_start(png_ptr, png_hIST, (png_uint_32)(num_hist * 2));
1195 for (i = 0; i < num_hist; i++)
1196 {
1197 png_save_uint_16(buf, hist[i]);
1198 png_write_chunk_data(png_ptr, buf, (png_size_t)2);
1199 }
1200 png_write_chunk_end(png_ptr);
1201 }
1202 #endif
1203
1204 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \
1205 defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
1206 /* Check that the tEXt or zTXt keyword is valid per PNG 1.0 specification,
1207 * and if invalid, correct the keyword rather than discarding the entire
1208 * chunk. The PNG 1.0 specification requires keywords 1-79 characters in
1209 * length, forbids leading or trailing whitespace, multiple internal spaces,
1210 * and the non-break space (0x80) from ISO 8859-1. Returns keyword length.
1211 *
1212 * The new_key is allocated to hold the corrected keyword and must be freed
1213 * by the calling routine. This avoids problems with trying to write to
1214 * static keywords without having to have duplicate copies of the strings.
1215 */
1216 png_size_t /* PRIVATE */
1217 png_check_keyword(png_structp png_ptr, png_charp key, png_charpp new_key)
1218 {
1219 png_size_t key_len;
1220 png_charp kp, dp;
1221 int kflag;
1222 int kwarn=0;
1223
1224 png_debug(1, "in png_check_keyword\n");
1225 *new_key = NULL;
1226
1227 if (key == NULL || (key_len = png_strlen(key)) == 0)
1228 {
1229 png_warning(png_ptr, "zero length keyword");
1230 return ((png_size_t)0);
1231 }
1232
1233 png_debug1(2, "Keyword to be checked is '%s'\n", key);
1234
1235 *new_key = (png_charp)png_malloc_warn(png_ptr, (png_uint_32)(key_len + 2));
1236 if (*new_key == NULL)
1237 {
1238 png_warning(png_ptr, "Out of memory while procesing keyword");
1239 return ((png_size_t)0);
1240 }
1241
1242 /* Replace non-printing characters with a blank and print a warning */
1243 for (kp = key, dp = *new_key; *kp != '\0'; kp++, dp++)
1244 {
1245 if ((png_byte)*kp < 0x20 ||
1246 ((png_byte)*kp > 0x7E && (png_byte)*kp < 0xA1))
1247 {
1248 #if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
1249 char msg[40];
1250
1251 png_snprintf(msg, 40,
1252 "invalid keyword character 0x%02X", (png_byte)*kp);
1253 png_warning(png_ptr, msg);
1254 #else
1255 png_warning(png_ptr, "invalid character in keyword");
1256 #endif
1257 *dp = ' ';
1258 }
1259 else
1260 {
1261 *dp = *kp;
1262 }
1263 }
1264 *dp = '\0';
1265
1266 /* Remove any trailing white space. */
1267 kp = *new_key + key_len - 1;
1268 if (*kp == ' ')
1269 {
1270 png_warning(png_ptr, "trailing spaces removed from keyword");
1271
1272 while (*kp == ' ')
1273 {
1274 *(kp--) = '\0';
1275 key_len--;
1276 }
1277 }
1278
1279 /* Remove any leading white space. */
1280 kp = *new_key;
1281 if (*kp == ' ')
1282 {
1283 png_warning(png_ptr, "leading spaces removed from keyword");
1284
1285 while (*kp == ' ')
1286 {
1287 kp++;
1288 key_len--;
1289 }
1290 }
1291
1292 png_debug1(2, "Checking for multiple internal spaces in '%s'\n", kp);
1293
1294 /* Remove multiple internal spaces. */
1295 for (kflag = 0, dp = *new_key; *kp != '\0'; kp++)
1296 {
1297 if (*kp == ' ' && kflag == 0)
1298 {
1299 *(dp++) = *kp;
1300 kflag = 1;
1301 }
1302 else if (*kp == ' ')
1303 {
1304 key_len--;
1305 kwarn=1;
1306 }
1307 else
1308 {
1309 *(dp++) = *kp;
1310 kflag = 0;
1311 }
1312 }
1313 *dp = '\0';
1314 if(kwarn)
1315 png_warning(png_ptr, "extra interior spaces removed from keyword");
1316
1317 if (key_len == 0)
1318 {
1319 png_free(png_ptr, *new_key);
1320 *new_key=NULL;
1321 png_warning(png_ptr, "Zero length keyword");
1322 }
1323
1324 if (key_len > 79)
1325 {
1326 png_warning(png_ptr, "keyword length must be 1 - 79 characters");
1327 new_key[79] = '\0';
1328 key_len = 79;
1329 }
1330
1331 return (key_len);
1332 }
1333 #endif
1334
1335 #if defined(PNG_WRITE_tEXt_SUPPORTED)
1336 /* write a tEXt chunk */
1337 void /* PRIVATE */
1338 png_write_tEXt(png_structp png_ptr, png_charp key, png_charp text,
1339 png_size_t text_len)
1340 {
1341 #ifdef PNG_USE_LOCAL_ARRAYS
1342 PNG_tEXt;
1343 #endif
1344 png_size_t key_len;
1345 png_charp new_key;
1346
1347 png_debug(1, "in png_write_tEXt\n");
1348 if (key == NULL || (key_len = png_check_keyword(png_ptr, key, &new_key))==0)
1349 {
1350 png_warning(png_ptr, "Empty keyword in tEXt chunk");
1351 return;
1352 }
1353
1354 if (text == NULL || *text == '\0')
1355 text_len = 0;
1356 else
1357 text_len = png_strlen(text);
1358
1359 /* make sure we include the 0 after the key */
1360 png_write_chunk_start(png_ptr, png_tEXt, (png_uint_32)key_len+text_len+1);
1361 /*
1362 * We leave it to the application to meet PNG-1.0 requirements on the
1363 * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of
1364 * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them.
1365 * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
1366 */
1367 png_write_chunk_data(png_ptr, (png_bytep)new_key, key_len + 1);
1368 if (text_len)
1369 png_write_chunk_data(png_ptr, (png_bytep)text, text_len);
1370
1371 png_write_chunk_end(png_ptr);
1372 png_free(png_ptr, new_key);
1373 }
1374 #endif
1375
1376 #if defined(PNG_WRITE_zTXt_SUPPORTED)
1377 /* write a compressed text chunk */
1378 void /* PRIVATE */
1379 png_write_zTXt(png_structp png_ptr, png_charp key, png_charp text,
1380 png_size_t text_len, int compression)
1381 {
1382 #ifdef PNG_USE_LOCAL_ARRAYS
1383 PNG_zTXt;
1384 #endif
1385 png_size_t key_len;
1386 char buf[1];
1387 png_charp new_key;
1388 compression_state comp;
1389
1390 png_debug(1, "in png_write_zTXt\n");
1391
1392 comp.num_output_ptr = 0;
1393 comp.max_output_ptr = 0;
1394 comp.output_ptr = NULL;
1395 comp.input = NULL;
1396 comp.input_len = 0;
1397
1398 if (key == NULL || (key_len = png_check_keyword(png_ptr, key, &new_key))==0)
1399 {
1400 png_warning(png_ptr, "Empty keyword in zTXt chunk");
1401 return;
1402 }
1403
1404 if (text == NULL || *text == '\0' || compression==PNG_TEXT_COMPRESSION_NONE)
1405 {
1406 png_write_tEXt(png_ptr, new_key, text, (png_size_t)0);
1407 png_free(png_ptr, new_key);
1408 return;
1409 }
1410
1411 text_len = png_strlen(text);
1412
1413 /* compute the compressed data; do it now for the length */
1414 text_len = png_text_compress(png_ptr, text, text_len, compression,
1415 &comp);
1416
1417 /* write start of chunk */
1418 png_write_chunk_start(png_ptr, png_zTXt, (png_uint_32)
1419 (key_len+text_len+2));
1420 /* write key */
1421 png_write_chunk_data(png_ptr, (png_bytep)new_key, key_len + 1);
1422 png_free(png_ptr, new_key);
1423
1424 buf[0] = (png_byte)compression;
1425 /* write compression */
1426 png_write_chunk_data(png_ptr, (png_bytep)buf, (png_size_t)1);
1427 /* write the compressed data */
1428 png_write_compressed_data_out(png_ptr, &comp);
1429
1430 /* close the chunk */
1431 png_write_chunk_end(png_ptr);
1432 }
1433 #endif
1434
1435 #if defined(PNG_WRITE_iTXt_SUPPORTED)
1436 /* write an iTXt chunk */
1437 void /* PRIVATE */
1438 png_write_iTXt(png_structp png_ptr, int compression, png_charp key,
1439 png_charp lang, png_charp lang_key, png_charp text)
1440 {
1441 #ifdef PNG_USE_LOCAL_ARRAYS
1442 PNG_iTXt;
1443 #endif
1444 png_size_t lang_len, key_len, lang_key_len, text_len;
1445 png_charp new_lang, new_key;
1446 png_byte cbuf[2];
1447 compression_state comp;
1448
1449 png_debug(1, "in png_write_iTXt\n");
1450
1451 comp.num_output_ptr = 0;
1452 comp.max_output_ptr = 0;
1453 comp.output_ptr = NULL;
1454 comp.input = NULL;
1455
1456 if (key == NULL || (key_len = png_check_keyword(png_ptr, key, &new_key))==0)
1457 {
1458 png_warning(png_ptr, "Empty keyword in iTXt chunk");
1459 return;
1460 }
1461 if (lang == NULL || (lang_len = png_check_keyword(png_ptr, lang, &new_lang))==0)
1462 {
1463 png_warning(png_ptr, "Empty language field in iTXt chunk");
1464 new_lang = NULL;
1465 lang_len = 0;
1466 }
1467
1468 if (lang_key == NULL)
1469 lang_key_len = 0;
1470 else
1471 lang_key_len = png_strlen(lang_key);
1472
1473 if (text == NULL)
1474 text_len = 0;
1475 else
1476 text_len = png_strlen(text);
1477
1478 /* compute the compressed data; do it now for the length */
1479 text_len = png_text_compress(png_ptr, text, text_len, compression-2,
1480 &comp);
1481
1482
1483 /* make sure we include the compression flag, the compression byte,
1484 * and the NULs after the key, lang, and lang_key parts */
1485
1486 png_write_chunk_start(png_ptr, png_iTXt,
1487 (png_uint_32)(
1488 5 /* comp byte, comp flag, terminators for key, lang and lang_key */
1489 + key_len
1490 + lang_len
1491 + lang_key_len
1492 + text_len));
1493
1494 /*
1495 * We leave it to the application to meet PNG-1.0 requirements on the
1496 * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of
1497 * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them.
1498 * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
1499 */
1500 png_write_chunk_data(png_ptr, (png_bytep)new_key, key_len + 1);
1501
1502 /* set the compression flag */
1503 if (compression == PNG_ITXT_COMPRESSION_NONE || \
1504 compression == PNG_TEXT_COMPRESSION_NONE)
1505 cbuf[0] = 0;
1506 else /* compression == PNG_ITXT_COMPRESSION_zTXt */
1507 cbuf[0] = 1;
1508 /* set the compression method */
1509 cbuf[1] = 0;
1510 png_write_chunk_data(png_ptr, cbuf, 2);
1511
1512 cbuf[0] = 0;
1513 png_write_chunk_data(png_ptr, (new_lang ? (png_bytep)new_lang : cbuf), lang_len + 1);
1514 png_write_chunk_data(png_ptr, (lang_key ? (png_bytep)lang_key : cbuf), lang_key_len + 1);
1515 png_write_compressed_data_out(png_ptr, &comp);
1516
1517 png_write_chunk_end(png_ptr);
1518 png_free(png_ptr, new_key);
1519 png_free(png_ptr, new_lang);
1520 }
1521 #endif
1522
1523 #if defined(PNG_WRITE_oFFs_SUPPORTED)
1524 /* write the oFFs chunk */
1525 void /* PRIVATE */
1526 png_write_oFFs(png_structp png_ptr, png_int_32 x_offset, png_int_32 y_offset,
1527 int unit_type)
1528 {
1529 #ifdef PNG_USE_LOCAL_ARRAYS
1530 PNG_oFFs;
1531 #endif
1532 png_byte buf[9];
1533
1534 png_debug(1, "in png_write_oFFs\n");
1535 if (unit_type >= PNG_OFFSET_LAST)
1536 png_warning(png_ptr, "Unrecognized unit type for oFFs chunk");
1537
1538 png_save_int_32(buf, x_offset);
1539 png_save_int_32(buf + 4, y_offset);
1540 buf[8] = (png_byte)unit_type;
1541
1542 png_write_chunk(png_ptr, png_oFFs, buf, (png_size_t)9);
1543 }
1544 #endif
1545 #if defined(PNG_WRITE_pCAL_SUPPORTED)
1546 /* write the pCAL chunk (described in the PNG extensions document) */
1547 void /* PRIVATE */
1548 png_write_pCAL(png_structp png_ptr, png_charp purpose, png_int_32 X0,
1549 png_int_32 X1, int type, int nparams, png_charp units, png_charpp params)
1550 {
1551 #ifdef PNG_USE_LOCAL_ARRAYS
1552 PNG_pCAL;
1553 #endif
1554 png_size_t purpose_len, units_len, total_len;
1555 png_uint_32p params_len;
1556 png_byte buf[10];
1557 png_charp new_purpose;
1558 int i;
1559
1560 png_debug1(1, "in png_write_pCAL (%d parameters)\n", nparams);
1561 if (type >= PNG_EQUATION_LAST)
1562 png_warning(png_ptr, "Unrecognized equation type for pCAL chunk");
1563
1564 purpose_len = png_check_keyword(png_ptr, purpose, &new_purpose) + 1;
1565 png_debug1(3, "pCAL purpose length = %d\n", (int)purpose_len);
1566 units_len = png_strlen(units) + (nparams == 0 ? 0 : 1);
1567 png_debug1(3, "pCAL units length = %d\n", (int)units_len);
1568 total_len = purpose_len + units_len + 10;
1569
1570 params_len = (png_uint_32p)png_malloc(png_ptr, (png_uint_32)(nparams
1571 *png_sizeof(png_uint_32)));
1572
1573 /* Find the length of each parameter, making sure we don't count the
1574 null terminator for the last parameter. */
1575 for (i = 0; i < nparams; i++)
1576 {
1577 params_len[i] = png_strlen(params[i]) + (i == nparams - 1 ? 0 : 1);
1578 png_debug2(3, "pCAL parameter %d length = %lu\n", i, params_len[i]);
1579 total_len += (png_size_t)params_len[i];
1580 }
1581
1582 png_debug1(3, "pCAL total length = %d\n", (int)total_len);
1583 png_write_chunk_start(png_ptr, png_pCAL, (png_uint_32)total_len);
1584 png_write_chunk_data(png_ptr, (png_bytep)new_purpose, purpose_len);
1585 png_save_int_32(buf, X0);
1586 png_save_int_32(buf + 4, X1);
1587 buf[8] = (png_byte)type;
1588 buf[9] = (png_byte)nparams;
1589 png_write_chunk_data(png_ptr, buf, (png_size_t)10);
1590 png_write_chunk_data(png_ptr, (png_bytep)units, (png_size_t)units_len);
1591
1592 png_free(png_ptr, new_purpose);
1593
1594 for (i = 0; i < nparams; i++)
1595 {
1596 png_write_chunk_data(png_ptr, (png_bytep)params[i],
1597 (png_size_t)params_len[i]);
1598 }
1599
1600 png_free(png_ptr, params_len);
1601 png_write_chunk_end(png_ptr);
1602 }
1603 #endif
1604
1605 #if defined(PNG_WRITE_sCAL_SUPPORTED)
1606 /* write the sCAL chunk */
1607 #if defined(PNG_FLOATING_POINT_SUPPORTED) && !defined(PNG_NO_STDIO)
1608 void /* PRIVATE */
1609 png_write_sCAL(png_structp png_ptr, int unit, double width, double height)
1610 {
1611 #ifdef PNG_USE_LOCAL_ARRAYS
1612 PNG_sCAL;
1613 #endif
1614 char buf[64];
1615 png_size_t total_len;
1616
1617 png_debug(1, "in png_write_sCAL\n");
1618
1619 buf[0] = (char)unit;
1620 #if defined(_WIN32_WCE)
1621 /* sprintf() function is not supported on WindowsCE */
1622 {
1623 wchar_t wc_buf[32];
1624 size_t wc_len;
1625 swprintf(wc_buf, TEXT("%12.12e"), width);
1626 wc_len = wcslen(wc_buf);
1627 WideCharToMultiByte(CP_ACP, 0, wc_buf, -1, buf + 1, wc_len, NULL, NULL);
1628 total_len = wc_len + 2;
1629 swprintf(wc_buf, TEXT("%12.12e"), height);
1630 wc_len = wcslen(wc_buf);
1631 WideCharToMultiByte(CP_ACP, 0, wc_buf, -1, buf + total_len, wc_len,
1632 NULL, NULL);
1633 total_len += wc_len;
1634 }
1635 #else
1636 png_snprintf(buf + 1, 63, "%12.12e", width);
1637 total_len = 1 + png_strlen(buf + 1) + 1;
1638 png_snprintf(buf + total_len, 64-total_len, "%12.12e", height);
1639 total_len += png_strlen(buf + total_len);
1640 #endif
1641
1642 png_debug1(3, "sCAL total length = %u\n", (unsigned int)total_len);
1643 png_write_chunk(png_ptr, png_sCAL, (png_bytep)buf, total_len);
1644 }
1645 #else
1646 #ifdef PNG_FIXED_POINT_SUPPORTED
1647 void /* PRIVATE */
1648 png_write_sCAL_s(png_structp png_ptr, int unit, png_charp width,
1649 png_charp height)
1650 {
1651 #ifdef PNG_USE_LOCAL_ARRAYS
1652 PNG_sCAL;
1653 #endif
1654 png_byte buf[64];
1655 png_size_t wlen, hlen, total_len;
1656
1657 png_debug(1, "in png_write_sCAL_s\n");
1658
1659 wlen = png_strlen(width);
1660 hlen = png_strlen(height);
1661 total_len = wlen + hlen + 2;
1662 if (total_len > 64)
1663 {
1664 png_warning(png_ptr, "Can't write sCAL (buffer too small)");
1665 return;
1666 }
1667
1668 buf[0] = (png_byte)unit;
1669 png_memcpy(buf + 1, width, wlen + 1); /* append the '\0' here */
1670 png_memcpy(buf + wlen + 2, height, hlen); /* do NOT append the '\0' here */
1671
1672 png_debug1(3, "sCAL total length = %u\n", (unsigned int)total_len);
1673 png_write_chunk(png_ptr, png_sCAL, buf, total_len);
1674 }
1675 #endif
1676 #endif
1677 #endif
1678
1679 #if defined(PNG_WRITE_pHYs_SUPPORTED)
1680 /* write the pHYs chunk */
1681 void /* PRIVATE */
1682 png_write_pHYs(png_structp png_ptr, png_uint_32 x_pixels_per_unit,
1683 png_uint_32 y_pixels_per_unit,
1684 int unit_type)
1685 {
1686 #ifdef PNG_USE_LOCAL_ARRAYS
1687 PNG_pHYs;
1688 #endif
1689 png_byte buf[9];
1690
1691 png_debug(1, "in png_write_pHYs\n");
1692 if (unit_type >= PNG_RESOLUTION_LAST)
1693 png_warning(png_ptr, "Unrecognized unit type for pHYs chunk");
1694
1695 png_save_uint_32(buf, x_pixels_per_unit);
1696 png_save_uint_32(buf + 4, y_pixels_per_unit);
1697 buf[8] = (png_byte)unit_type;
1698
1699 png_write_chunk(png_ptr, png_pHYs, buf, (png_size_t)9);
1700 }
1701 #endif
1702
1703 #if defined(PNG_WRITE_tIME_SUPPORTED)
1704 /* Write the tIME chunk. Use either png_convert_from_struct_tm()
1705 * or png_convert_from_time_t(), or fill in the structure yourself.
1706 */
1707 void /* PRIVATE */
1708 png_write_tIME(png_structp png_ptr, png_timep mod_time)
1709 {
1710 #ifdef PNG_USE_LOCAL_ARRAYS
1711 PNG_tIME;
1712 #endif
1713 png_byte buf[7];
1714
1715 png_debug(1, "in png_write_tIME\n");
1716 if (mod_time->month > 12 || mod_time->month < 1 ||
1717 mod_time->day > 31 || mod_time->day < 1 ||
1718 mod_time->hour > 23 || mod_time->second > 60)
1719 {
1720 png_warning(png_ptr, "Invalid time specified for tIME chunk");
1721 return;
1722 }
1723
1724 png_save_uint_16(buf, mod_time->year);
1725 buf[2] = mod_time->month;
1726 buf[3] = mod_time->day;
1727 buf[4] = mod_time->hour;
1728 buf[5] = mod_time->minute;
1729 buf[6] = mod_time->second;
1730
1731 png_write_chunk(png_ptr, png_tIME, buf, (png_size_t)7);
1732 }
1733 #endif
1734
1735 /* initializes the row writing capability of libpng */
1736 void /* PRIVATE */
1737 png_write_start_row(png_structp png_ptr)
1738 {
1739 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1740 #ifdef PNG_USE_LOCAL_ARRAYS
1741 /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
1742
1743 /* start of interlace block */
1744 int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
1745
1746 /* offset to next interlace block */
1747 int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
1748
1749 /* start of interlace block in the y direction */
1750 int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
1751
1752 /* offset to next interlace block in the y direction */
1753 int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
1754 #endif
1755 #endif
1756
1757 png_size_t buf_size;
1758
1759 png_debug(1, "in png_write_start_row\n");
1760 buf_size = (png_size_t)(PNG_ROWBYTES(
1761 png_ptr->usr_channels*png_ptr->usr_bit_depth,png_ptr->width)+1);
1762
1763 /* set up row buffer */
1764 png_ptr->row_buf = (png_bytep)png_malloc(png_ptr, (png_uint_32)buf_size);
1765 png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE;
1766
1767 #ifndef PNG_NO_WRITE_FILTERING
1768 /* set up filtering buffer, if using this filter */
1769 if (png_ptr->do_filter & PNG_FILTER_SUB)
1770 {
1771 png_ptr->sub_row = (png_bytep)png_malloc(png_ptr,
1772 (png_ptr->rowbytes + 1));
1773 png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
1774 }
1775
1776 /* We only need to keep the previous row if we are using one of these. */
1777 if (png_ptr->do_filter & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH))
1778 {
1779 /* set up previous row buffer */
1780 png_ptr->prev_row = (png_bytep)png_malloc(png_ptr, (png_uint_32)buf_size);
1781 png_memset(png_ptr->prev_row, 0, buf_size);
1782
1783 if (png_ptr->do_filter & PNG_FILTER_UP)
1784 {
1785 png_ptr->up_row = (png_bytep)png_malloc(png_ptr,
1786 (png_ptr->rowbytes + 1));
1787 png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
1788 }
1789
1790 if (png_ptr->do_filter & PNG_FILTER_AVG)
1791 {
1792 png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
1793 (png_ptr->rowbytes + 1));
1794 png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
1795 }
1796
1797 if (png_ptr->do_filter & PNG_FILTER_PAETH)
1798 {
1799 png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,
1800 (png_ptr->rowbytes + 1));
1801 png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
1802 }
1803 #endif /* PNG_NO_WRITE_FILTERING */
1804 }
1805
1806 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1807 /* if interlaced, we need to set up width and height of pass */
1808 if (png_ptr->interlaced)
1809 {
1810 if (!(png_ptr->transformations & PNG_INTERLACE))
1811 {
1812 png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
1813 png_pass_ystart[0]) / png_pass_yinc[0];
1814 png_ptr->usr_width = (png_ptr->width + png_pass_inc[0] - 1 -
1815 png_pass_start[0]) / png_pass_inc[0];
1816 }
1817 else
1818 {
1819 png_ptr->num_rows = png_ptr->height;
1820 png_ptr->usr_width = png_ptr->width;
1821 }
1822 }
1823 else
1824 #endif
1825 {
1826 png_ptr->num_rows = png_ptr->height;
1827 png_ptr->usr_width = png_ptr->width;
1828 }
1829 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1830 png_ptr->zstream.next_out = png_ptr->zbuf;
1831 }
1832
1833 /* Internal use only. Called when finished processing a row of data. */
1834 void /* PRIVATE */
1835 png_write_finish_row(png_structp png_ptr)
1836 {
1837 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1838 #ifdef PNG_USE_LOCAL_ARRAYS
1839 /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
1840
1841 /* start of interlace block */
1842 int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
1843
1844 /* offset to next interlace block */
1845 int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
1846
1847 /* start of interlace block in the y direction */
1848 int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
1849
1850 /* offset to next interlace block in the y direction */
1851 int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
1852 #endif
1853 #endif
1854
1855 int ret;
1856
1857 png_debug(1, "in png_write_finish_row\n");
1858 /* next row */
1859 png_ptr->row_number++;
1860
1861 /* see if we are done */
1862 if (png_ptr->row_number < png_ptr->num_rows)
1863 return;
1864
1865 #ifdef PNG_WRITE_INTERLACING_SUPPORTED
1866 /* if interlaced, go to next pass */
1867 if (png_ptr->interlaced)
1868 {
1869 png_ptr->row_number = 0;
1870 if (png_ptr->transformations & PNG_INTERLACE)
1871 {
1872 png_ptr->pass++;
1873 }
1874 else
1875 {
1876 /* loop until we find a non-zero width or height pass */
1877 do
1878 {
1879 png_ptr->pass++;
1880 if (png_ptr->pass >= 7)
1881 break;
1882 png_ptr->usr_width = (png_ptr->width +
1883 png_pass_inc[png_ptr->pass] - 1 -
1884 png_pass_start[png_ptr->pass]) /
1885 png_pass_inc[png_ptr->pass];
1886 png_ptr->num_rows = (png_ptr->height +
1887 png_pass_yinc[png_ptr->pass] - 1 -
1888 png_pass_ystart[png_ptr->pass]) /
1889 png_pass_yinc[png_ptr->pass];
1890 if (png_ptr->transformations & PNG_INTERLACE)
1891 break;
1892 } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0);
1893
1894 }
1895
1896 /* reset the row above the image for the next pass */
1897 if (png_ptr->pass < 7)
1898 {
1899 if (png_ptr->prev_row != NULL)
1900 png_memset(png_ptr->prev_row, 0,
1901 (png_size_t)(PNG_ROWBYTES(png_ptr->usr_channels*
1902 png_ptr->usr_bit_depth,png_ptr->width))+1);
1903 return;
1904 }
1905 }
1906 #endif
1907
1908 /* if we get here, we've just written the last row, so we need
1909 to flush the compressor */
1910 do
1911 {
1912 /* tell the compressor we are done */
1913 ret = deflate(&png_ptr->zstream, Z_FINISH);
1914 /* check for an error */
1915 if (ret == Z_OK)
1916 {
1917 /* check to see if we need more room */
1918 if (!(png_ptr->zstream.avail_out))
1919 {
1920 png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
1921 png_ptr->zstream.next_out = png_ptr->zbuf;
1922 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1923 }
1924 }
1925 else if (ret != Z_STREAM_END)
1926 {
1927 if (png_ptr->zstream.msg != NULL)
1928 png_error(png_ptr, png_ptr->zstream.msg);
1929 else
1930 png_error(png_ptr, "zlib error");
1931 }
1932 } while (ret != Z_STREAM_END);
1933
1934 /* write any extra space */
1935 if (png_ptr->zstream.avail_out < png_ptr->zbuf_size)
1936 {
1937 png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size -
1938 png_ptr->zstream.avail_out);
1939 }
1940
1941 deflateReset(&png_ptr->zstream);
1942 png_ptr->zstream.data_type = Z_BINARY;
1943 }
1944
1945 #if defined(PNG_WRITE_INTERLACING_SUPPORTED)
1946 /* Pick out the correct pixels for the interlace pass.
1947 * The basic idea here is to go through the row with a source
1948 * pointer and a destination pointer (sp and dp), and copy the
1949 * correct pixels for the pass. As the row gets compacted,
1950 * sp will always be >= dp, so we should never overwrite anything.
1951 * See the default: case for the easiest code to understand.
1952 */
1953 void /* PRIVATE */
1954 png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
1955 {
1956 #ifdef PNG_USE_LOCAL_ARRAYS
1957 /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
1958
1959 /* start of interlace block */
1960 int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
1961
1962 /* offset to next interlace block */
1963 int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
1964 #endif
1965
1966 png_debug(1, "in png_do_write_interlace\n");
1967 /* we don't have to do anything on the last pass (6) */
1968 #if defined(PNG_USELESS_TESTS_SUPPORTED)
1969 if (row != NULL && row_info != NULL && pass < 6)
1970 #else
1971 if (pass < 6)
1972 #endif
1973 {
1974 /* each pixel depth is handled separately */
1975 switch (row_info->pixel_depth)
1976 {
1977 case 1:
1978 {
1979 png_bytep sp;
1980 png_bytep dp;
1981 int shift;
1982 int d;
1983 int value;
1984 png_uint_32 i;
1985 png_uint_32 row_width = row_info->width;
1986
1987 dp = row;
1988 d = 0;
1989 shift = 7;
1990 for (i = png_pass_start[pass]; i < row_width;
1991 i += png_pass_inc[pass])
1992 {
1993 sp = row + (png_size_t)(i >> 3);
1994 value = (int)(*sp >> (7 - (int)(i & 0x07))) & 0x01;
1995 d |= (value << shift);
1996
1997 if (shift == 0)
1998 {
1999 shift = 7;
2000 *dp++ = (png_byte)d;
2001 d = 0;
2002 }
2003 else
2004 shift--;
2005
2006 }
2007 if (shift != 7)
2008 *dp = (png_byte)d;
2009 break;
2010 }
2011 case 2:
2012 {
2013 png_bytep sp;
2014 png_bytep dp;
2015 int shift;
2016 int d;
2017 int value;
2018 png_uint_32 i;
2019 png_uint_32 row_width = row_info->width;
2020
2021 dp = row;
2022 shift = 6;
2023 d = 0;
2024 for (i = png_pass_start[pass]; i < row_width;
2025 i += png_pass_inc[pass])
2026 {
2027 sp = row + (png_size_t)(i >> 2);
2028 value = (*sp >> ((3 - (int)(i & 0x03)) << 1)) & 0x03;
2029 d |= (value << shift);
2030
2031 if (shift == 0)
2032 {
2033 shift = 6;
2034 *dp++ = (png_byte)d;
2035 d = 0;
2036 }
2037 else
2038 shift -= 2;
2039 }
2040 if (shift != 6)
2041 *dp = (png_byte)d;
2042 break;
2043 }
2044 case 4:
2045 {
2046 png_bytep sp;
2047 png_bytep dp;
2048 int shift;
2049 int d;
2050 int value;
2051 png_uint_32 i;
2052 png_uint_32 row_width = row_info->width;
2053
2054 dp = row;
2055 shift = 4;
2056 d = 0;
2057 for (i = png_pass_start[pass]; i < row_width;
2058 i += png_pass_inc[pass])
2059 {
2060 sp = row + (png_size_t)(i >> 1);
2061 value = (*sp >> ((1 - (int)(i & 0x01)) << 2)) & 0x0f;
2062 d |= (value << shift);
2063
2064 if (shift == 0)
2065 {
2066 shift = 4;
2067 *dp++ = (png_byte)d;
2068 d = 0;
2069 }
2070 else
2071 shift -= 4;
2072 }
2073 if (shift != 4)
2074 *dp = (png_byte)d;
2075 break;
2076 }
2077 default:
2078 {
2079 png_bytep sp;
2080 png_bytep dp;
2081 png_uint_32 i;
2082 png_uint_32 row_width = row_info->width;
2083 png_size_t pixel_bytes;
2084
2085 /* start at the beginning */
2086 dp = row;
2087 /* find out how many bytes each pixel takes up */
2088 pixel_bytes = (row_info->pixel_depth >> 3);
2089 /* loop through the row, only looking at the pixels that
2090 matter */
2091 for (i = png_pass_start[pass]; i < row_width;
2092 i += png_pass_inc[pass])
2093 {
2094 /* find out where the original pixel is */
2095 sp = row + (png_size_t)i * pixel_bytes;
2096 /* move the pixel */
2097 if (dp != sp)
2098 png_memcpy(dp, sp, pixel_bytes);
2099 /* next pixel */
2100 dp += pixel_bytes;
2101 }
2102 break;
2103 }
2104 }
2105 /* set new row width */
2106 row_info->width = (row_info->width +
2107 png_pass_inc[pass] - 1 -
2108 png_pass_start[pass]) /
2109 png_pass_inc[pass];
2110 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
2111 row_info->width);
2112 }
2113 }
2114 #endif
2115
2116 /* This filters the row, chooses which filter to use, if it has not already
2117 * been specified by the application, and then writes the row out with the
2118 * chosen filter.
2119 */
2120 #define PNG_MAXSUM (((png_uint_32)(-1)) >> 1)
2121 #define PNG_HISHIFT 10
2122 #define PNG_LOMASK ((png_uint_32)0xffffL)
2123 #define PNG_HIMASK ((png_uint_32)(~PNG_LOMASK >> PNG_HISHIFT))
2124 void /* PRIVATE */
2125 png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
2126 {
2127 png_bytep best_row;
2128 #ifndef PNG_NO_WRITE_FILTER
2129 png_bytep prev_row, row_buf;
2130 png_uint_32 mins, bpp;
2131 png_byte filter_to_do = png_ptr->do_filter;
2132 png_uint_32 row_bytes = row_info->rowbytes;
2133 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2134 int num_p_filters = (int)png_ptr->num_prev_filters;
2135 #endif
2136
2137 png_debug(1, "in png_write_find_filter\n");
2138 /* find out how many bytes offset each pixel is */
2139 bpp = (row_info->pixel_depth + 7) >> 3;
2140
2141 prev_row = png_ptr->prev_row;
2142 #endif
2143 best_row = png_ptr->row_buf;
2144 #ifndef PNG_NO_WRITE_FILTER
2145 row_buf = best_row;
2146 mins = PNG_MAXSUM;
2147
2148 /* The prediction method we use is to find which method provides the
2149 * smallest value when summing the absolute values of the distances
2150 * from zero, using anything >= 128 as negative numbers. This is known
2151 * as the "minimum sum of absolute differences" heuristic. Other
2152 * heuristics are the "weighted minimum sum of absolute differences"
2153 * (experimental and can in theory improve compression), and the "zlib
2154 * predictive" method (not implemented yet), which does test compressions
2155 * of lines using different filter methods, and then chooses the
2156 * (series of) filter(s) that give minimum compressed data size (VERY
2157 * computationally expensive).
2158 *
2159 * GRR 980525: consider also
2160 * (1) minimum sum of absolute differences from running average (i.e.,
2161 * keep running sum of non-absolute differences & count of bytes)
2162 * [track dispersion, too? restart average if dispersion too large?]
2163 * (1b) minimum sum of absolute differences from sliding average, probably
2164 * with window size <= deflate window (usually 32K)
2165 * (2) minimum sum of squared differences from zero or running average
2166 * (i.e., ~ root-mean-square approach)
2167 */
2168
2169
2170 /* We don't need to test the 'no filter' case if this is the only filter
2171 * that has been chosen, as it doesn't actually do anything to the data.
2172 */
2173 if ((filter_to_do & PNG_FILTER_NONE) &&
2174 filter_to_do != PNG_FILTER_NONE)
2175 {
2176 png_bytep rp;
2177 png_uint_32 sum = 0;
2178 png_uint_32 i;
2179 int v;
2180
2181 for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
2182 {
2183 v = *rp;
2184 sum += (v < 128) ? v : 256 - v;
2185 }
2186
2187 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2188 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2189 {
2190 png_uint_32 sumhi, sumlo;
2191 int j;
2192 sumlo = sum & PNG_LOMASK;
2193 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; /* Gives us some footroom */
2194
2195 /* Reduce the sum if we match any of the previous rows */
2196 for (j = 0; j < num_p_filters; j++)
2197 {
2198 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
2199 {
2200 sumlo = (sumlo * png_ptr->filter_weights[j]) >>
2201 PNG_WEIGHT_SHIFT;
2202 sumhi = (sumhi * png_ptr->filter_weights[j]) >>
2203 PNG_WEIGHT_SHIFT;
2204 }
2205 }
2206
2207 /* Factor in the cost of this filter (this is here for completeness,
2208 * but it makes no sense to have a "cost" for the NONE filter, as
2209 * it has the minimum possible computational cost - none).
2210 */
2211 sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>
2212 PNG_COST_SHIFT;
2213 sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>
2214 PNG_COST_SHIFT;
2215
2216 if (sumhi > PNG_HIMASK)
2217 sum = PNG_MAXSUM;
2218 else
2219 sum = (sumhi << PNG_HISHIFT) + sumlo;
2220 }
2221 #endif
2222 mins = sum;
2223 }
2224
2225 /* sub filter */
2226 if (filter_to_do == PNG_FILTER_SUB)
2227 /* it's the only filter so no testing is needed */
2228 {
2229 png_bytep rp, lp, dp;
2230 png_uint_32 i;
2231 for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
2232 i++, rp++, dp++)
2233 {
2234 *dp = *rp;
2235 }
2236 for (lp = row_buf + 1; i < row_bytes;
2237 i++, rp++, lp++, dp++)
2238 {
2239 *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
2240 }
2241 best_row = png_ptr->sub_row;
2242 }
2243
2244 else if (filter_to_do & PNG_FILTER_SUB)
2245 {
2246 png_bytep rp, dp, lp;
2247 png_uint_32 sum = 0, lmins = mins;
2248 png_uint_32 i;
2249 int v;
2250
2251 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2252 /* We temporarily increase the "minimum sum" by the factor we
2253 * would reduce the sum of this filter, so that we can do the
2254 * early exit comparison without scaling the sum each time.
2255 */
2256 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2257 {
2258 int j;
2259 png_uint_32 lmhi, lmlo;
2260 lmlo = lmins & PNG_LOMASK;
2261 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
2262
2263 for (j = 0; j < num_p_filters; j++)
2264 {
2265 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
2266 {
2267 lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
2268 PNG_WEIGHT_SHIFT;
2269 lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
2270 PNG_WEIGHT_SHIFT;
2271 }
2272 }
2273
2274 lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
2275 PNG_COST_SHIFT;
2276 lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
2277 PNG_COST_SHIFT;
2278
2279 if (lmhi > PNG_HIMASK)
2280 lmins = PNG_MAXSUM;
2281 else
2282 lmins = (lmhi << PNG_HISHIFT) + lmlo;
2283 }
2284 #endif
2285
2286 for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
2287 i++, rp++, dp++)
2288 {
2289 v = *dp = *rp;
2290
2291 sum += (v < 128) ? v : 256 - v;
2292 }
2293 for (lp = row_buf + 1; i < row_bytes;
2294 i++, rp++, lp++, dp++)
2295 {
2296 v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
2297
2298 sum += (v < 128) ? v : 256 - v;
2299
2300 if (sum > lmins) /* We are already worse, don't continue. */
2301 break;
2302 }
2303
2304 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2305 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2306 {
2307 int j;
2308 png_uint_32 sumhi, sumlo;
2309 sumlo = sum & PNG_LOMASK;
2310 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
2311
2312 for (j = 0; j < num_p_filters; j++)
2313 {
2314 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
2315 {
2316 sumlo = (sumlo * png_ptr->inv_filter_weights[j]) >>
2317 PNG_WEIGHT_SHIFT;
2318 sumhi = (sumhi * png_ptr->inv_filter_weights[j]) >>
2319 PNG_WEIGHT_SHIFT;
2320 }
2321 }
2322
2323 sumlo = (sumlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
2324 PNG_COST_SHIFT;
2325 sumhi = (sumhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
2326 PNG_COST_SHIFT;
2327
2328 if (sumhi > PNG_HIMASK)
2329 sum = PNG_MAXSUM;
2330 else
2331 sum = (sumhi << PNG_HISHIFT) + sumlo;
2332 }
2333 #endif
2334
2335 if (sum < mins)
2336 {
2337 mins = sum;
2338 best_row = png_ptr->sub_row;
2339 }
2340 }
2341
2342 /* up filter */
2343 if (filter_to_do == PNG_FILTER_UP)
2344 {
2345 png_bytep rp, dp, pp;
2346 png_uint_32 i;
2347
2348 for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
2349 pp = prev_row + 1; i < row_bytes;
2350 i++, rp++, pp++, dp++)
2351 {
2352 *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
2353 }
2354 best_row = png_ptr->up_row;
2355 }
2356
2357 else if (filter_to_do & PNG_FILTER_UP)
2358 {
2359 png_bytep rp, dp, pp;
2360 png_uint_32 sum = 0, lmins = mins;
2361 png_uint_32 i;
2362 int v;
2363
2364
2365 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2366 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2367 {
2368 int j;
2369 png_uint_32 lmhi, lmlo;
2370 lmlo = lmins & PNG_LOMASK;
2371 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
2372
2373 for (j = 0; j < num_p_filters; j++)
2374 {
2375 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
2376 {
2377 lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
2378 PNG_WEIGHT_SHIFT;
2379 lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
2380 PNG_WEIGHT_SHIFT;
2381 }
2382 }
2383
2384 lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
2385 PNG_COST_SHIFT;
2386 lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
2387 PNG_COST_SHIFT;
2388
2389 if (lmhi > PNG_HIMASK)
2390 lmins = PNG_MAXSUM;
2391 else
2392 lmins = (lmhi << PNG_HISHIFT) + lmlo;
2393 }
2394 #endif
2395
2396 for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
2397 pp = prev_row + 1; i < row_bytes; i++)
2398 {
2399 v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
2400
2401 sum += (v < 128) ? v : 256 - v;
2402
2403 if (sum > lmins) /* We are already worse, don't continue. */
2404 break;
2405 }
2406
2407 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2408 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2409 {
2410 int j;
2411 png_uint_32 sumhi, sumlo;
2412 sumlo = sum & PNG_LOMASK;
2413 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
2414
2415 for (j = 0; j < num_p_filters; j++)
2416 {
2417 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
2418 {
2419 sumlo = (sumlo * png_ptr->filter_weights[j]) >>
2420 PNG_WEIGHT_SHIFT;
2421 sumhi = (sumhi * png_ptr->filter_weights[j]) >>
2422 PNG_WEIGHT_SHIFT;
2423 }
2424 }
2425
2426 sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
2427 PNG_COST_SHIFT;
2428 sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
2429 PNG_COST_SHIFT;
2430
2431 if (sumhi > PNG_HIMASK)
2432 sum = PNG_MAXSUM;
2433 else
2434 sum = (sumhi << PNG_HISHIFT) + sumlo;
2435 }
2436 #endif
2437
2438 if (sum < mins)
2439 {
2440 mins = sum;
2441 best_row = png_ptr->up_row;
2442 }
2443 }
2444
2445 /* avg filter */
2446 if (filter_to_do == PNG_FILTER_AVG)
2447 {
2448 png_bytep rp, dp, pp, lp;
2449 png_uint_32 i;
2450 for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
2451 pp = prev_row + 1; i < bpp; i++)
2452 {
2453 *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
2454 }
2455 for (lp = row_buf + 1; i < row_bytes; i++)
2456 {
2457 *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
2458 & 0xff);
2459 }
2460 best_row = png_ptr->avg_row;
2461 }
2462
2463 else if (filter_to_do & PNG_FILTER_AVG)
2464 {
2465 png_bytep rp, dp, pp, lp;
2466 png_uint_32 sum = 0, lmins = mins;
2467 png_uint_32 i;
2468 int v;
2469
2470 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2471 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2472 {
2473 int j;
2474 png_uint_32 lmhi, lmlo;
2475 lmlo = lmins & PNG_LOMASK;
2476 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
2477
2478 for (j = 0; j < num_p_filters; j++)
2479 {
2480 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_AVG)
2481 {
2482 lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
2483 PNG_WEIGHT_SHIFT;
2484 lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
2485 PNG_WEIGHT_SHIFT;
2486 }
2487 }
2488
2489 lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
2490 PNG_COST_SHIFT;
2491 lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
2492 PNG_COST_SHIFT;
2493
2494 if (lmhi > PNG_HIMASK)
2495 lmins = PNG_MAXSUM;
2496 else
2497 lmins = (lmhi << PNG_HISHIFT) + lmlo;
2498 }
2499 #endif
2500
2501 for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
2502 pp = prev_row + 1; i < bpp; i++)
2503 {
2504 v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
2505
2506 sum += (v < 128) ? v : 256 - v;
2507 }
2508 for (lp = row_buf + 1; i < row_bytes; i++)
2509 {
2510 v = *dp++ =
2511 (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) & 0xff);
2512
2513 sum += (v < 128) ? v : 256 - v;
2514
2515 if (sum > lmins) /* We are already worse, don't continue. */
2516 break;
2517 }
2518
2519 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2520 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2521 {
2522 int j;
2523 png_uint_32 sumhi, sumlo;
2524 sumlo = sum & PNG_LOMASK;
2525 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
2526
2527 for (j = 0; j < num_p_filters; j++)
2528 {
2529 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
2530 {
2531 sumlo = (sumlo * png_ptr->filter_weights[j]) >>
2532 PNG_WEIGHT_SHIFT;
2533 sumhi = (sumhi * png_ptr->filter_weights[j]) >>
2534 PNG_WEIGHT_SHIFT;
2535 }
2536 }
2537
2538 sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
2539 PNG_COST_SHIFT;
2540 sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
2541 PNG_COST_SHIFT;
2542
2543 if (sumhi > PNG_HIMASK)
2544 sum = PNG_MAXSUM;
2545 else
2546 sum = (sumhi << PNG_HISHIFT) + sumlo;
2547 }
2548 #endif
2549
2550 if (sum < mins)
2551 {
2552 mins = sum;
2553 best_row = png_ptr->avg_row;
2554 }
2555 }
2556
2557 /* Paeth filter */
2558 if (filter_to_do == PNG_FILTER_PAETH)
2559 {
2560 png_bytep rp, dp, pp, cp, lp;
2561 png_uint_32 i;
2562 for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
2563 pp = prev_row + 1; i < bpp; i++)
2564 {
2565 *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
2566 }
2567
2568 for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
2569 {
2570 int a, b, c, pa, pb, pc, p;
2571
2572 b = *pp++;
2573 c = *cp++;
2574 a = *lp++;
2575
2576 p = b - c;
2577 pc = a - c;
2578
2579 #ifdef PNG_USE_ABS
2580 pa = abs(p);
2581 pb = abs(pc);
2582 pc = abs(p + pc);
2583 #else
2584 pa = p < 0 ? -p : p;
2585 pb = pc < 0 ? -pc : pc;
2586 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
2587 #endif
2588
2589 p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
2590
2591 *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
2592 }
2593 best_row = png_ptr->paeth_row;
2594 }
2595
2596 else if (filter_to_do & PNG_FILTER_PAETH)
2597 {
2598 png_bytep rp, dp, pp, cp, lp;
2599 png_uint_32 sum = 0, lmins = mins;
2600 png_uint_32 i;
2601 int v;
2602
2603 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2604 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2605 {
2606 int j;
2607 png_uint_32 lmhi, lmlo;
2608 lmlo = lmins & PNG_LOMASK;
2609 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
2610
2611 for (j = 0; j < num_p_filters; j++)
2612 {
2613 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
2614 {
2615 lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
2616 PNG_WEIGHT_SHIFT;
2617 lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
2618 PNG_WEIGHT_SHIFT;
2619 }
2620 }
2621
2622 lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>
2623 PNG_COST_SHIFT;
2624 lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>
2625 PNG_COST_SHIFT;
2626
2627 if (lmhi > PNG_HIMASK)
2628 lmins = PNG_MAXSUM;
2629 else
2630 lmins = (lmhi << PNG_HISHIFT) + lmlo;
2631 }
2632 #endif
2633
2634 for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
2635 pp = prev_row + 1; i < bpp; i++)
2636 {
2637 v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
2638
2639 sum += (v < 128) ? v : 256 - v;
2640 }
2641
2642 for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
2643 {
2644 int a, b, c, pa, pb, pc, p;
2645
2646 b = *pp++;
2647 c = *cp++;
2648 a = *lp++;
2649
2650 #ifndef PNG_SLOW_PAETH
2651 p = b - c;
2652 pc = a - c;
2653 #ifdef PNG_USE_ABS
2654 pa = abs(p);
2655 pb = abs(pc);
2656 pc = abs(p + pc);
2657 #else
2658 pa = p < 0 ? -p : p;
2659 pb = pc < 0 ? -pc : pc;
2660 pc = (p + pc) < 0 ? -(p + pc) : p + pc;
2661 #endif
2662 p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
2663 #else /* PNG_SLOW_PAETH */
2664 p = a + b - c;
2665 pa = abs(p - a);
2666 pb = abs(p - b);
2667 pc = abs(p - c);
2668 if (pa <= pb && pa <= pc)
2669 p = a;
2670 else if (pb <= pc)
2671 p = b;
2672 else
2673 p = c;
2674 #endif /* PNG_SLOW_PAETH */
2675
2676 v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
2677
2678 sum += (v < 128) ? v : 256 - v;
2679
2680 if (sum > lmins) /* We are already worse, don't continue. */
2681 break;
2682 }
2683
2684 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2685 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
2686 {
2687 int j;
2688 png_uint_32 sumhi, sumlo;
2689 sumlo = sum & PNG_LOMASK;
2690 sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
2691
2692 for (j = 0; j < num_p_filters; j++)
2693 {
2694 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
2695 {
2696 sumlo = (sumlo * png_ptr->filter_weights[j]) >>
2697 PNG_WEIGHT_SHIFT;
2698 sumhi = (sumhi * png_ptr->filter_weights[j]) >>
2699 PNG_WEIGHT_SHIFT;
2700 }
2701 }
2702
2703 sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>
2704 PNG_COST_SHIFT;
2705 sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>
2706 PNG_COST_SHIFT;
2707
2708 if (sumhi > PNG_HIMASK)
2709 sum = PNG_MAXSUM;
2710 else
2711 sum = (sumhi << PNG_HISHIFT) + sumlo;
2712 }
2713 #endif
2714
2715 if (sum < mins)
2716 {
2717 best_row = png_ptr->paeth_row;
2718 }
2719 }
2720 #endif /* PNG_NO_WRITE_FILTER */
2721 /* Do the actual writing of the filtered row data from the chosen filter. */
2722
2723 png_write_filtered_row(png_ptr, best_row);
2724
2725 #ifndef PNG_NO_WRITE_FILTER
2726 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
2727 /* Save the type of filter we picked this time for future calculations */
2728 if (png_ptr->num_prev_filters > 0)
2729 {
2730 int j;
2731 for (j = 1; j < num_p_filters; j++)
2732 {
2733 png_ptr->prev_filters[j] = png_ptr->prev_filters[j - 1];
2734 }
2735 png_ptr->prev_filters[j] = best_row[0];
2736 }
2737 #endif
2738 #endif /* PNG_NO_WRITE_FILTER */
2739 }
2740
2741
2742 /* Do the actual writing of a previously filtered row. */
2743 void /* PRIVATE */
2744 png_write_filtered_row(png_structp png_ptr, png_bytep filtered_row)
2745 {
2746 png_debug(1, "in png_write_filtered_row\n");
2747 png_debug1(2, "filter = %d\n", filtered_row[0]);
2748 /* set up the zlib input buffer */
2749
2750 png_ptr->zstream.next_in = filtered_row;
2751 png_ptr->zstream.avail_in = (uInt)png_ptr->row_info.rowbytes + 1;
2752 /* repeat until we have compressed all the data */
2753 do
2754 {
2755 int ret; /* return of zlib */
2756
2757 /* compress the data */
2758 ret = deflate(&png_ptr->zstream, Z_NO_FLUSH);
2759 /* check for compression errors */
2760 if (ret != Z_OK)
2761 {
2762 if (png_ptr->zstream.msg != NULL)
2763 png_error(png_ptr, png_ptr->zstream.msg);
2764 else
2765 png_error(png_ptr, "zlib error");
2766 }
2767
2768 /* see if it is time to write another IDAT */
2769 if (!(png_ptr->zstream.avail_out))
2770 {
2771 /* write the IDAT and reset the zlib output buffer */
2772 png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
2773 png_ptr->zstream.next_out = png_ptr->zbuf;
2774 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
2775 }
2776 /* repeat until all data has been compressed */
2777 } while (png_ptr->zstream.avail_in);
2778
2779 /* swap the current and previous rows */
2780 if (png_ptr->prev_row != NULL)
2781 {
2782 png_bytep tptr;
2783
2784 tptr = png_ptr->prev_row;
2785 png_ptr->prev_row = png_ptr->row_buf;
2786 png_ptr->row_buf = tptr;
2787 }
2788
2789 /* finish row - updates counters and flushes zlib if last row */
2790 png_write_finish_row(png_ptr);
2791
2792 #if defined(PNG_WRITE_FLUSH_SUPPORTED)
2793 png_ptr->flush_rows++;
2794
2795 if (png_ptr->flush_dist > 0 &&
2796 png_ptr->flush_rows >= png_ptr->flush_dist)
2797 {
2798 png_write_flush(png_ptr);
2799 }
2800 #endif
2801 }
2802 #endif /* PNG_WRITE_SUPPORTED */