istereo2: 643f4ab609a4 libs/libpng/pngwutil.c

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view libs/libpng/pngwutil.c @ 35:643f4ab609a4

added readme and license

author	John Tsiombikas <nuclear@member.fsf.org>
date	Sat, 31 Oct 2015 05:45:35 +0200
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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

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;

102

103 /* write the length and the chunk name */

104 png_save_uint_32(buf, length);

105 png_memcpy(buf + 4, chunk_name, 4);

106 png_write_data(png_ptr, buf, (png_size_t)8);

107 /* put the chunk name into png_ptr->chunk_name */

108 png_memcpy(png_ptr->chunk_name, chunk_name, 4);

109 /* reset the crc and run it over the chunk name */

110 png_reset_crc(png_ptr);

111 png_calculate_crc(png_ptr, chunk_name, (png_size_t)4);

112 }

113

114 /* Write the data of a PNG chunk started with png_write_chunk_start().

115 * Note that multiple calls to this function are allowed, and that the

116 * sum of the lengths from these calls *must* add up to the total_length

117 * given to png_write_chunk_start().

118 */

119 void PNGAPI

120 png_write_chunk_data(png_structp png_ptr, png_bytep data, png_size_t length)

121 {

122 /* write the data, and run the CRC over it */

123 if (png_ptr == NULL) return;

124 if (data != NULL && length > 0)

125 {

126 png_write_data(png_ptr, data, length);

127 /* update the CRC after writing the data,

128 * in case that the user I/O routine alters it.

129 */

130 png_calculate_crc(png_ptr, data, length);

131 }

132 }

133

134 /* Finish a chunk started with png_write_chunk_start(). */

135 void PNGAPI

136 png_write_chunk_end(png_structp png_ptr)

137 {

138 png_byte buf[4];

139

140 if (png_ptr == NULL) return;

141

142 /* write the crc in a single operation */

143 png_save_uint_32(buf, png_ptr->crc);

144

145 png_write_data(png_ptr, buf, (png_size_t)4);

146 }

147

148 #if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_iCCP_SUPPORTED)

149 /*

150 * This pair of functions encapsulates the operation of (a) compressing a

151 * text string, and (b) issuing it later as a series of chunk data writes.

152 * The compression_state structure is shared context for these functions

153 * set up by the caller in order to make the whole mess thread-safe.

154 */

155

156 typedef struct

157 {

158 char *input; /* the uncompressed input data */

159 int input_len; /* its length */

160 int num_output_ptr; /* number of output pointers used */

161 int max_output_ptr; /* size of output_ptr */

162 png_charpp output_ptr; /* array of pointers to output */

163 } compression_state;

164

165 /* compress given text into storage in the png_ptr structure */

166 static int /* PRIVATE */

167 png_text_compress(png_structp png_ptr,

168 png_charp text, png_size_t text_len, int compression,

169 compression_state *comp)

170 {

171 int ret;

172

173 comp->num_output_ptr = 0;

174 comp->max_output_ptr = 0;

175 comp->output_ptr = NULL;

176 comp->input = NULL;

177 comp->input_len = 0;

178

179 /* we may just want to pass the text right through */

180 if (compression == PNG_TEXT_COMPRESSION_NONE)

181 {

182 comp->input = text;

183 comp->input_len = text_len;

184 return((int)text_len);

185 }

186

187 if (compression >= PNG_TEXT_COMPRESSION_LAST)

188 {

189 #if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)

190 char msg[50];

191 png_snprintf(msg, 50, "Unknown compression type %d", compression);

192 png_warning(png_ptr, msg);

193 #else

194 png_warning(png_ptr, "Unknown compression type");

195 #endif

196 }

197

198 /* We can't write the chunk until we find out how much data we have,

199 * which means we need to run the compressor first and save the

200 * output. This shouldn't be a problem, as the vast majority of

201 * comments should be reasonable, but we will set up an array of

202 * malloc'd pointers to be sure.

203 *

204 * If we knew the application was well behaved, we could simplify this

205 * greatly by assuming we can always malloc an output buffer large

206 * enough to hold the compressed text ((1001 * text_len / 1000) + 12)

207 * and malloc this directly. The only time this would be a bad idea is

208 * if we can't malloc more than 64K and we have 64K of random input

209 * data, or if the input string is incredibly large (although this

210 * wouldn't cause a failure, just a slowdown due to swapping).

211 */

212

213 /* set up the compression buffers */

214 png_ptr->zstream.avail_in = (uInt)text_len;

215 png_ptr->zstream.next_in = (Bytef *)text;

216 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;

217 png_ptr->zstream.next_out = (Bytef *)png_ptr->zbuf;

218

219 /* this is the same compression loop as in png_write_row() */

220 do

221 {

222 /* compress the data */

223 ret = deflate(&png_ptr->zstream, Z_NO_FLUSH);

224 if (ret != Z_OK)

225 {

226 /* error */

227 if (png_ptr->zstream.msg != NULL)

228 png_error(png_ptr, png_ptr->zstream.msg);

229 else

230 png_error(png_ptr, "zlib error");

231 }

232 /* check to see if we need more room */

233 if (!(png_ptr->zstream.avail_out))

234 {

235 /* make sure the output array has room */

236 if (comp->num_output_ptr >= comp->max_output_ptr)

237 {

238 int old_max;

239

240 old_max = comp->max_output_ptr;

241 comp->max_output_ptr = comp->num_output_ptr + 4;

242 if (comp->output_ptr != NULL)

243 {

244 png_charpp old_ptr;

245

246 old_ptr = comp->output_ptr;

247 comp->output_ptr = (png_charpp)png_malloc(png_ptr,

248 (png_uint_32)

249 (comp->max_output_ptr * png_sizeof(png_charpp)));

250 png_memcpy(comp->output_ptr, old_ptr, old_max

251 * png_sizeof(png_charp));

252 png_free(png_ptr, old_ptr);

253 }

254 else

255 comp->output_ptr = (png_charpp)png_malloc(png_ptr,

256 (png_uint_32)

257 (comp->max_output_ptr * png_sizeof(png_charp)));

258 }

259

260 /* save the data */

261 comp->output_ptr[comp->num_output_ptr] =

262 (png_charp)png_malloc(png_ptr,

263 (png_uint_32)png_ptr->zbuf_size);

264 png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf,

265 png_ptr->zbuf_size);

266 comp->num_output_ptr++;

267

268 /* and reset the buffer */

269 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;

270 png_ptr->zstream.next_out = png_ptr->zbuf;

271 }

272 /* continue until we don't have any more to compress */

273 } while (png_ptr->zstream.avail_in);

274

275 /* finish the compression */

276 do

277 {

278 /* tell zlib we are finished */

279 ret = deflate(&png_ptr->zstream, Z_FINISH);

280

281 if (ret == Z_OK)

282 {

283 /* check to see if we need more room */

284 if (!(png_ptr->zstream.avail_out))

285 {

286 /* check to make sure our output array has room */

287 if (comp->num_output_ptr >= comp->max_output_ptr)

288 {

289 int old_max;

290

291 old_max = comp->max_output_ptr;

292 comp->max_output_ptr = comp->num_output_ptr + 4;

293 if (comp->output_ptr != NULL)

294 {

295 png_charpp old_ptr;

296

297 old_ptr = comp->output_ptr;

298 /* This could be optimized to realloc() */

299 comp->output_ptr = (png_charpp)png_malloc(png_ptr,

300 (png_uint_32)(comp->max_output_ptr *

301 png_sizeof(png_charp)));

302 png_memcpy(comp->output_ptr, old_ptr,

303 old_max * png_sizeof(png_charp));

304 png_free(png_ptr, old_ptr);

305 }

306 else

307 comp->output_ptr = (png_charpp)png_malloc(png_ptr,

308 (png_uint_32)(comp->max_output_ptr *

309 png_sizeof(png_charp)));

310 }

311

312 /* save off the data */

313 comp->output_ptr[comp->num_output_ptr] =

314 (png_charp)png_malloc(png_ptr,

315 (png_uint_32)png_ptr->zbuf_size);

316 png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf,

317 png_ptr->zbuf_size);

318 comp->num_output_ptr++;

319

320 /* and reset the buffer pointers */

321 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;

322 png_ptr->zstream.next_out = png_ptr->zbuf;

323 }

324 }

325 else if (ret != Z_STREAM_END)

326 {

327 /* we got an error */

328 if (png_ptr->zstream.msg != NULL)

329 png_error(png_ptr, png_ptr->zstream.msg);

330 else

331 png_error(png_ptr, "zlib error");

332 }

333 } while (ret != Z_STREAM_END);

334

335 /* text length is number of buffers plus last buffer */

336 text_len = png_ptr->zbuf_size * comp->num_output_ptr;

337 if (png_ptr->zstream.avail_out < png_ptr->zbuf_size)

338 text_len += png_ptr->zbuf_size - (png_size_t)png_ptr->zstream.avail_out;

339

340 return((int)text_len);

341 }

342

343 /* ship the compressed text out via chunk writes */

344 static void /* PRIVATE */

345 png_write_compressed_data_out(png_structp png_ptr, compression_state *comp)

346 {

347 int i;

348

349 /* handle the no-compression case */

350 if (comp->input)

351 {

352 png_write_chunk_data(png_ptr, (png_bytep)comp->input,

353 (png_size_t)comp->input_len);

354 return;

355 }

356

357 /* write saved output buffers, if any */

358 for (i = 0; i < comp->num_output_ptr; i++)

359 {

360 png_write_chunk_data(png_ptr, (png_bytep)comp->output_ptr[i],

361 (png_size_t)png_ptr->zbuf_size);

362 png_free(png_ptr, comp->output_ptr[i]);

363 comp->output_ptr[i]=NULL;

364 }

365 if (comp->max_output_ptr != 0)

366 png_free(png_ptr, comp->output_ptr);

367 comp->output_ptr=NULL;

368 /* write anything left in zbuf */

369 if (png_ptr->zstream.avail_out < (png_uint_32)png_ptr->zbuf_size)

370 png_write_chunk_data(png_ptr, png_ptr->zbuf,

371 (png_size_t)(png_ptr->zbuf_size - png_ptr->zstream.avail_out));

372

373 /* reset zlib for another zTXt/iTXt or image data */

374 deflateReset(&png_ptr->zstream);

375 png_ptr->zstream.data_type = Z_BINARY;

376 }

377 #endif

378

379 /* Write the IHDR chunk, and update the png_struct with the necessary

380 * information. Note that the rest of this code depends upon this

381 * information being correct.

382 */

383 void /* PRIVATE */

384 png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height,

385 int bit_depth, int color_type, int compression_type, int filter_type,

386 int interlace_type)

387 {

388 #ifdef PNG_USE_LOCAL_ARRAYS

389 PNG_IHDR;

390 #endif

391 int ret;

392

393 png_byte buf[13]; /* buffer to store the IHDR info */

394

395 png_debug(1, "in png_write_IHDR\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 }

438

439 if (compression_type != PNG_COMPRESSION_TYPE_BASE)

440 {

441 png_warning(png_ptr, "Invalid compression type specified");

442 compression_type = PNG_COMPRESSION_TYPE_BASE;

443 }

444

445 /* Write filter_method 64 (intrapixel differencing) only if

446 * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and

447 * 2. Libpng did not write a PNG signature (this filter_method is only

448 * used in PNG datastreams that are embedded in MNG datastreams) and

449 * 3. The application called png_permit_mng_features with a mask that

450 * included PNG_FLAG_MNG_FILTER_64 and

451 * 4. The filter_method is 64 and

452 * 5. The color_type is RGB or RGBA

453 */

454 if (

455 #if defined(PNG_MNG_FEATURES_SUPPORTED)

456 !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&

457 ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) &&

458 (color_type == PNG_COLOR_TYPE_RGB ||

459 color_type == PNG_COLOR_TYPE_RGB_ALPHA) &&

460 (filter_type == PNG_INTRAPIXEL_DIFFERENCING)) &&

461 #endif

462 filter_type != PNG_FILTER_TYPE_BASE)

463 {

464 png_warning(png_ptr, "Invalid filter type specified");

465 filter_type = PNG_FILTER_TYPE_BASE;

466 }

467

468 #ifdef PNG_WRITE_INTERLACING_SUPPORTED

469 if (interlace_type != PNG_INTERLACE_NONE &&

470 interlace_type != PNG_INTERLACE_ADAM7)

471 {

472 png_warning(png_ptr, "Invalid interlace type specified");

473 interlace_type = PNG_INTERLACE_ADAM7;

474 }

475 #else

476 interlace_type=PNG_INTERLACE_NONE;

477 #endif

478

479 /* save off the relevent information */

480 png_ptr->bit_depth = (png_byte)bit_depth;

481 png_ptr->color_type = (png_byte)color_type;

482 png_ptr->interlaced = (png_byte)interlace_type;

483 #if defined(PNG_MNG_FEATURES_SUPPORTED)

484 png_ptr->filter_type = (png_byte)filter_type;

485 #endif

486 png_ptr->compression_type = (png_byte)compression_type;

487 png_ptr->width = width;

488 png_ptr->height = height;

489

490 png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels);

491 png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, width);

492 /* set the usr info, so any transformations can modify it */

493 png_ptr->usr_width = png_ptr->width;

494 png_ptr->usr_bit_depth = png_ptr->bit_depth;

495 png_ptr->usr_channels = png_ptr->channels;

496

497 /* pack the header information into the buffer */

498 png_save_uint_32(buf, width);

499 png_save_uint_32(buf + 4, height);

500 buf[8] = (png_byte)bit_depth;

501 buf[9] = (png_byte)color_type;

502 buf[10] = (png_byte)compression_type;

503 buf[11] = (png_byte)filter_type;

504 buf[12] = (png_byte)interlace_type;

505

506 /* write the chunk */

507 png_write_chunk(png_ptr, (png_bytep)png_IHDR, buf, (png_size_t)13);

508

509 /* initialize zlib with PNG info */

510 png_ptr->zstream.zalloc = png_zalloc;

511 png_ptr->zstream.zfree = png_zfree;

512 png_ptr->zstream.opaque = (voidpf)png_ptr;

513 if (!(png_ptr->do_filter))

514 {

515 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||

516 png_ptr->bit_depth < 8)

517 png_ptr->do_filter = PNG_FILTER_NONE;

518 else

519 png_ptr->do_filter = PNG_ALL_FILTERS;

520 }

521 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY))

522 {

523 if (png_ptr->do_filter != PNG_FILTER_NONE)

524 png_ptr->zlib_strategy = Z_FILTERED;

525 else

526 png_ptr->zlib_strategy = Z_DEFAULT_STRATEGY;

527 }

528 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_LEVEL))

529 png_ptr->zlib_level = Z_DEFAULT_COMPRESSION;

530 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL))

531 png_ptr->zlib_mem_level = 8;

532 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS))

533 png_ptr->zlib_window_bits = 15;

534 if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_METHOD))

535 png_ptr->zlib_method = 8;

536 ret = deflateInit2(&png_ptr->zstream, png_ptr->zlib_level,

537 png_ptr->zlib_method, png_ptr->zlib_window_bits,

538 png_ptr->zlib_mem_level, png_ptr->zlib_strategy);

539 if (ret != Z_OK)

540 {

541 if (ret == Z_VERSION_ERROR) png_error(png_ptr,

542 "zlib failed to initialize compressor -- version error");

543 if (ret == Z_STREAM_ERROR) png_error(png_ptr,

544 "zlib failed to initialize compressor -- stream error");

545 if (ret == Z_MEM_ERROR) png_error(png_ptr,

546 "zlib failed to initialize compressor -- mem error");

547 png_error(png_ptr, "zlib failed to initialize compressor");

548 }

549 png_ptr->zstream.next_out = png_ptr->zbuf;

550 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;

551 /* libpng is not interested in zstream.data_type */

552 /* set it to a predefined value, to avoid its evaluation inside zlib */

553 png_ptr->zstream.data_type = Z_BINARY;

554

555 png_ptr->mode = PNG_HAVE_IHDR;

556 }

557

558 /* write the palette. We are careful not to trust png_color to be in the

559 * correct order for PNG, so people can redefine it to any convenient

560 * structure.

561 */

562 void /* PRIVATE */

563 png_write_PLTE(png_structp png_ptr, png_colorp palette, png_uint_32 num_pal)

564 {

565 #ifdef PNG_USE_LOCAL_ARRAYS

566 PNG_PLTE;

567 #endif

568 png_uint_32 i;

569 png_colorp pal_ptr;

570 png_byte buf[3];

571

572 png_debug(1, "in png_write_PLTE\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 }

589

590 if (!(png_ptr->color_type&PNG_COLOR_MASK_COLOR))

591 {

592 png_warning(png_ptr,

593 "Ignoring request to write a PLTE chunk in grayscale PNG");

594 return;

595 }

596

597 png_ptr->num_palette = (png_uint_16)num_pal;

598 png_debug1(3, "num_palette = %d\n", png_ptr->num_palette);

599

600 png_write_chunk_start(png_ptr, (png_bytep)png_PLTE,

601 (png_uint_32)(num_pal * 3));

602 #ifndef PNG_NO_POINTER_INDEXING

603 for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++)

604 {

605 buf[0] = pal_ptr->red;

606 buf[1] = pal_ptr->green;

607 buf[2] = pal_ptr->blue;

608 png_write_chunk_data(png_ptr, buf, (png_size_t)3);

609 }

610 #else

611 /* This is a little slower but some buggy compilers need to do this instead */

612 pal_ptr=palette;

613 for (i = 0; i < num_pal; i++)

614 {

615 buf[0] = pal_ptr[i].red;

616 buf[1] = pal_ptr[i].green;

617 buf[2] = pal_ptr[i].blue;

618 png_write_chunk_data(png_ptr, buf, (png_size_t)3);

619 }

620 #endif

621 png_write_chunk_end(png_ptr);

622 png_ptr->mode |= PNG_HAVE_PLTE;

623 }

624

625 /* write an IDAT chunk */

626 void /* PRIVATE */

627 png_write_IDAT(png_structp png_ptr, png_bytep data, png_size_t length)

628 {

629 #ifdef PNG_USE_LOCAL_ARRAYS

630 PNG_IDAT;

631 #endif

632 png_debug(1, "in png_write_IDAT\n");

633

634 /* Optimize the CMF field in the zlib stream. */

635 /* This hack of the zlib stream is compliant to the stream specification. */

636 if (!(png_ptr->mode & PNG_HAVE_IDAT) &&

637 png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)

638 {

639 unsigned int z_cmf = data[0]; /* zlib compression method and flags */

640 if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70)

641 {

642 /* Avoid memory underflows and multiplication overflows. */

643 /* The conditions below are practically always satisfied;

644 however, they still must be checked. */

645 if (length >= 2 &&

646 png_ptr->height < 16384 && png_ptr->width < 16384)

647 {

648 png_uint_32 uncompressed_idat_size = png_ptr->height *

649 ((png_ptr->width *

650 png_ptr->channels * png_ptr->bit_depth + 15) >> 3);

651 unsigned int z_cinfo = z_cmf >> 4;

652 unsigned int half_z_window_size = 1 << (z_cinfo + 7);

653 while (uncompressed_idat_size <= half_z_window_size &&

654 half_z_window_size >= 256)

655 {

656 z_cinfo--;

657 half_z_window_size >>= 1;

658 }

659 z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4);

660 if (data[0] != (png_byte)z_cmf)

661 {

662 data[0] = (png_byte)z_cmf;

663 data[1] &= 0xe0;

664 data[1] += (png_byte)(0x1f - ((z_cmf << 8) + data[1]) % 0x1f);

665 }

666 }

667 }

668 else

669 png_error(png_ptr,

670 "Invalid zlib compression method or flags in IDAT");

671 }

672

673 png_write_chunk(png_ptr, (png_bytep)png_IDAT, data, length);

674 png_ptr->mode |= PNG_HAVE_IDAT;

675 }

676

677 /* write an IEND chunk */

678 void /* PRIVATE */

679 png_write_IEND(png_structp png_ptr)

680 {

681 #ifdef PNG_USE_LOCAL_ARRAYS

682 PNG_IEND;

683 #endif

684 png_debug(1, "in png_write_IEND\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 }

689

690 #if defined(PNG_WRITE_gAMA_SUPPORTED)

691 /* write a gAMA chunk */

692 #ifdef PNG_FLOATING_POINT_SUPPORTED

693 void /* PRIVATE */

694 png_write_gAMA(png_structp png_ptr, double file_gamma)

695 {

696 #ifdef PNG_USE_LOCAL_ARRAYS

697 PNG_gAMA;

698 #endif

699 png_uint_32 igamma;

700 png_byte buf[4];

701

702 png_debug(1, "in png_write_gAMA\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];

717

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

725

726 #if defined(PNG_WRITE_sRGB_SUPPORTED)

727 /* write a sRGB chunk */

728 void /* PRIVATE */

729 png_write_sRGB(png_structp png_ptr, int srgb_intent)

730 {

731 #ifdef PNG_USE_LOCAL_ARRAYS

732 PNG_sRGB;

733 #endif

734 png_byte buf[1];

735

736 png_debug(1, "in png_write_sRGB\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

744

745 #if defined(PNG_WRITE_iCCP_SUPPORTED)

746 /* write an iCCP chunk */

747 void /* PRIVATE */

748 png_write_iCCP(png_structp png_ptr, png_charp name, int compression_type,

749 png_charp profile, int profile_len)

750 {

751 #ifdef PNG_USE_LOCAL_ARRAYS

752 PNG_iCCP;

753 #endif

754 png_size_t name_len;

755 png_charp new_name;

756 compression_state comp;

757 int embedded_profile_len = 0;

758

759 png_debug(1, "in png_write_iCCP\n");

760

761 comp.num_output_ptr = 0;

762 comp.max_output_ptr = 0;

763 comp.output_ptr = NULL;

764 comp.input = NULL;

765 comp.input_len = 0;

766

767 if (name == 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 }

773

774 if (compression_type != PNG_COMPRESSION_TYPE_BASE)

775 png_warning(png_ptr, "Unknown compression type in iCCP chunk");

776

777 if (profile == NULL)

778 profile_len = 0;

779

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)) );

786

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 }

793

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 }

800

801 if (profile_len)

802 profile_len = png_text_compress(png_ptr, profile,

803 (png_size_t)profile_len, PNG_COMPRESSION_TYPE_BASE, &comp);

804

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));

811

812 if (profile_len)

813 png_write_compressed_data_out(png_ptr, &comp);

814

815 png_write_chunk_end(png_ptr);

816 png_free(png_ptr, new_name);

817 }

818 #endif

819

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

837

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 }

845

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);

852

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

898

899 png_write_chunk_end(png_ptr);

900 png_free(png_ptr, new_name);

901 }

902 #endif

903

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;

914

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;

920

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 }

945

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 }

955

956 png_write_chunk(png_ptr, (png_bytep)png_sBIT, buf, size);

957 }

958 #endif

959

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;

973

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);

989

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);

999

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);

1009

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);

1019

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];

1034

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);

1048

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);

1056

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);

1064

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);

1072

1073 png_write_chunk(png_ptr, (png_bytep)png_cHRM, buf, (png_size_t)32);

1074 }

1075 #endif

1076 #endif

1077

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];

1088

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

1133

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];

1143

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

1186

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];

1197

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 }

1206

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

1217

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;

1237

1238 png_debug(1, "in png_check_keyword\n");

1239 *new_key = NULL;

1240

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 }

1246

1247 png_debug1(2, "Keyword to be checked is '%s'\n", key);

1248

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 }

1255

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];

1264

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';

1279

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");

1285

1286 while (*kp == ' ')

1287 {

1288 *(kp--) = '\0';

1289 key_len--;

1290 }

1291 }

1292

1293 /* Remove any leading white space. */

1294 kp = *new_key;

1295 if (*kp == ' ')

1296 {

1297 png_warning(png_ptr, "leading spaces removed from keyword");

1298

1299 while (*kp == ' ')

1300 {

1301 kp++;

1302 key_len--;

1303 }

1304 }

1305

1306 png_debug1(2, "Checking for multiple internal spaces in '%s'\n", kp);

1307

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");

1330

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 }

1337

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 }

1344

1345 return (key_len);

1346 }

1347 #endif

1348

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;

1360

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 }

1367

1368 if (text == NULL || *text == '\0')

1369 text_len = 0;

1370 else

1371 text_len = png_strlen(text);

1372

1373 /* make sure we include the 0 after the key */

1374 png_write_chunk_start(png_ptr, (png_bytep)png_tEXt,

1375 (png_uint_32)(key_len + text_len + 1));

1376 /*

1377 * We leave it to the application to meet PNG-1.0 requirements on the

1378 * contents of the text. PNG-1.0 through PNG-1.2 discourage the use of

1379 * any non-Latin-1 characters except for NEWLINE. ISO PNG will forbid them.

1380 * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.

1381 */

1382 png_write_chunk_data(png_ptr, (png_bytep)new_key,

1383 (png_size_t)(key_len + 1));

1384 if (text_len)

1385 png_write_chunk_data(png_ptr, (png_bytep)text, (png_size_t)text_len);

1386

1387 png_write_chunk_end(png_ptr);

1388 png_free(png_ptr, new_key);

1389 }

1390 #endif

1391

1392 #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;

1405

1406 png_debug(1, "in png_write_zTXt\n");

1407

1408 comp.num_output_ptr = 0;

1409 comp.max_output_ptr = 0;

1410 comp.output_ptr = NULL;

1411 comp.input = NULL;

1412 comp.input_len = 0;

1413

1414 if (key == 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 }

1420

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 }

1427

1428 text_len = png_strlen(text);

1429

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);

1433

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);

1441

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);

1447

1448 /* close the chunk */

1449 png_write_chunk_end(png_ptr);

1450 }

1451 #endif

1452

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;

1466

1467 png_debug(1, "in png_write_iTXt\n");

1468

1469 comp.num_output_ptr = 0;

1470 comp.max_output_ptr = 0;

1471 comp.output_ptr = NULL;

1472 comp.input = NULL;

1473

1474 if (key == 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 }

1485

1486 if (lang_key == NULL)

1487 lang_key_len = 0;

1488 else

1489 lang_key_len = png_strlen(lang_key);

1490

1491 if (text == NULL)

1492 text_len = 0;

1493 else

1494 text_len = png_strlen(text);

1495

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);

1499

1500

1501 /* make sure we include the compression flag, the compression byte,

1502 * and the NULs after the key, lang, and lang_key parts */

1503

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));

1511

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));

1520

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);

1530

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);

1537

1538 png_write_chunk_end(png_ptr);

1539 png_free(png_ptr, new_key);

1540 png_free(png_ptr, new_lang);

1541 }

1542 #endif

1543

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];

1554

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");

1558

1559 png_save_int_32(buf, x_offset);

1560 png_save_int_32(buf + 4, y_offset);

1561 buf[8] = (png_byte)unit_type;

1562

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;

1580

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");

1584

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;

1590

1591 params_len = (png_uint_32p)png_malloc(png_ptr,

1592 (png_uint_32)(nparams * png_sizeof(png_uint_32)));

1593

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 }

1603

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);

1614

1615 png_free(png_ptr, new_purpose);

1616

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 }

1622

1623 png_free(png_ptr, params_len);

1624 png_write_chunk_end(png_ptr);

1625 }

1626 #endif

1627

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;

1639

1640 png_debug(1, "in png_write_sCAL\n");

1641

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

1664

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;

1679

1680 png_debug(1, "in png_write_sCAL_s\n");

1681

1682 wlen = png_strlen(width);

1683 hlen = png_strlen(height);

1684 total_len = wlen + hlen + 2;

1685 if (total_len > 64)

1686 {

1687 png_warning(png_ptr, "Can't write sCAL (buffer too small)");

1688 return;

1689 }

1690

1691 buf[0] = (png_byte)unit;

1692 png_memcpy(buf + 1, width, wlen + 1); /* append the '\0' here */

1693 png_memcpy(buf + wlen + 2, height, hlen); /* do NOT append the '\0' here */

1694

1695 png_debug1(3, "sCAL total length = %u\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

1701

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];

1713

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");

1717

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;

1721

1722 png_write_chunk(png_ptr, (png_bytep)png_pHYs, buf, (png_size_t)9);

1723 }

1724 #endif

1725

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];

1737

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 }

1746

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;

1753

1754 png_write_chunk(png_ptr, (png_bytep)png_tIME, buf, (png_size_t)7);

1755 }

1756 #endif

1757

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 */

1765

1766 /* start of interlace block */

1767 int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};

1768

1769 /* offset to next interlace block */

1770 int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};

1771

1772 /* start of interlace block in the y direction */

1773 int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};

1774

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

1779

1780 png_size_t buf_size;

1781

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);

1785

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;

1790

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 }

1799

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);

1807

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 }

1814

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 }

1821

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 */

1830

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 }

1857

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 */

1865

1866 /* start of interlace block */

1867 int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};

1868

1869 /* offset to next interlace block */

1870 int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};

1871

1872 /* start of interlace block in the y direction */

1873 int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};

1874

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

1879

1880 int ret;

1881

1882 png_debug(1, "in png_write_finish_row\n");

1883 /* next row */

1884 png_ptr->row_number++;

1885

1886 /* see if we are done */

1887 if (png_ptr->row_number < png_ptr->num_rows)

1888 return;

1889

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);

1918

1919 }

1920

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

1932

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);

1958

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 }

1965

1966 deflateReset(&png_ptr->zstream);

1967 png_ptr->zstream.data_type = Z_BINARY;

1968 }

1969

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 */

1983

1984 /* start of interlace block */

1985 int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};

1986

1987 /* offset to next interlace block */

1988 int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};

1989 #endif

1990

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;

2011

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);

2021

2022 if (shift == 0)

2023 {

2024 shift = 7;

2025 *dp++ = (png_byte)d;

2026 d = 0;

2027 }

2028 else

2029 shift--;

2030

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;

2045

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);

2055

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;

2078

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);

2088

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;

2109

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

2140

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

2161

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;

2165

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;

2172

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 */

2193

2194

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;

2205

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 }

2211

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 */

2219

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 }

2231

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;

2240

2241 if (sumhi > PNG_HIMASK)

2242 sum = PNG_MAXSUM;

2243 else

2244 sum = (sumhi << PNG_HISHIFT) + sumlo;

2245 }

2246 #endif

2247 mins = sum;

2248 }

2249

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 }

2268

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;

2275

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;

2287

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 }

2298

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;

2303

2304 if (lmhi > PNG_HIMASK)

2305 lmins = PNG_MAXSUM;

2306 else

2307 lmins = (lmhi << PNG_HISHIFT) + lmlo;

2308 }

2309 #endif

2310

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;

2315

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);

2322

2323 sum += (v < 128) ? v : 256 - v;

2324

2325 if (sum > lmins) /* We are already worse, don't continue. */

2326 break;

2327 }

2328

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;

2336

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 }

2347

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;

2352

2353 if (sumhi > PNG_HIMASK)

2354 sum = PNG_MAXSUM;

2355 else

2356 sum = (sumhi << PNG_HISHIFT) + sumlo;

2357 }

2358 #endif

2359

2360 if (sum < mins)

2361 {

2362 mins = sum;

2363 best_row = png_ptr->sub_row;

2364 }

2365 }

2366

2367 /* up filter */

2368 if (filter_to_do == PNG_FILTER_UP)

2369 {

2370 png_bytep rp, dp, pp;

2371 png_uint_32 i;

2372

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 }

2381

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;

2388

2389

2390 #if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)

2391 if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)

2392 {

2393 int j;

2394 png_uint_32 lmhi, lmlo;

2395 lmlo = lmins & PNG_LOMASK;

2396 lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;

2397

2398 for (j = 0; j < num_p_filters; j++)

2399 {

2400 if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)

2401 {

2402 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 }

2408

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;

2413

2414 if (lmhi > PNG_HIMASK)

2415 lmins = PNG_MAXSUM;

2416 else

2417 lmins = (lmhi << PNG_HISHIFT) + lmlo;

2418 }

2419 #endif

2420

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);

2425

2426 sum += (v < 128) ? v : 256 - v;

2427

2428 if (sum > lmins) /* We are already worse, don't continue. */

2429 break;

2430 }

2431

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;

2439

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 }

2450

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;

2455

2456 if (sumhi > PNG_HIMASK)

2457 sum = PNG_MAXSUM;

2458 else

2459 sum = (sumhi << PNG_HISHIFT) + sumlo;

2460 }

2461 #endif

2462

2463 if (sum < mins)

2464 {

2465 mins = sum;

2466 best_row = png_ptr->up_row;

2467 }

2468 }

2469

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 }

2487

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;

2494

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;

2502

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 }

2513

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;

2518

2519 if (lmhi > PNG_HIMASK)

2520 lmins = PNG_MAXSUM;

2521 else

2522 lmins = (lmhi << PNG_HISHIFT) + lmlo;

2523 }

2524 #endif

2525

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);

2530

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);

2537

2538 sum += (v < 128) ? v : 256 - v;

2539

2540 if (sum > lmins) /* We are already worse, don't continue. */

2541 break;

2542 }

2543

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;

2551

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 }

2562

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;

2567

2568 if (sumhi > PNG_HIMASK)

2569 sum = PNG_MAXSUM;

2570 else

2571 sum = (sumhi << PNG_HISHIFT) + sumlo;

2572 }

2573 #endif

2574

2575 if (sum < mins)

2576 {

2577 mins = sum;

2578 best_row = png_ptr->avg_row;

2579 }

2580 }

2581

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 }

2592

2593 for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)

2594 {

2595 int a, b, c, pa, pb, pc, p;

2596

2597 b = *pp++;

2598 c = *cp++;

2599 a = *lp++;

2600

2601 p = b - c;

2602 pc = a - c;

2603

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

2613

2614 p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;

2615

2616 *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);

2617 }

2618 best_row = png_ptr->paeth_row;

2619 }

2620

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;

2627

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;

2635

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 }

2646

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;

2651

2652 if (lmhi > PNG_HIMASK)

2653 lmins = PNG_MAXSUM;

2654 else

2655 lmins = (lmhi << PNG_HISHIFT) + lmlo;

2656 }

2657 #endif

2658

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);

2663

2664 sum += (v < 128) ? v : 256 - v;

2665 }

2666

2667 for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)

2668 {

2669 int a, b, c, pa, pb, pc, p;

2670

2671 b = *pp++;

2672 c = *cp++;

2673 a = *lp++;

2674

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 */

2700

2701 v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);

2702

2703 sum += (v < 128) ? v : 256 - v;

2704

2705 if (sum > lmins) /* We are already worse, don't continue. */

2706 break;

2707 }

2708

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;

2716

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 }

2727

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;

2732

2733 if (sumhi > PNG_HIMASK)

2734 sum = PNG_MAXSUM;

2735 else

2736 sum = (sumhi << PNG_HISHIFT) + sumlo;

2737 }

2738 #endif

2739

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. */

2747

2748 png_write_filtered_row(png_ptr, best_row);

2749

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 }

2765

2766

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 */

2774

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 */

2781

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 }

2792

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);

2803

2804 /* swap the current and previous rows */

2805 if (png_ptr->prev_row != NULL)

2806 {

2807 png_bytep tptr;

2808

2809 tptr = png_ptr->prev_row;

2810 png_ptr->prev_row = png_ptr->row_buf;

2811 png_ptr->row_buf = tptr;

2812 }

2813

2814 /* finish row - updates counters and flushes zlib if last row */

2815 png_write_finish_row(png_ptr);

2816

2817 #if defined(PNG_WRITE_FLUSH_SUPPORTED)

2818 png_ptr->flush_rows++;

2819

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 */