The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 1 | /*--------------------------------------------------------------------------- |
| 2 | |
| 3 | rpng2 - progressive-model PNG display program readpng2.c |
| 4 | |
| 5 | --------------------------------------------------------------------------- |
| 6 | |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame] | 7 | Copyright (c) 1998-2015 Greg Roelofs. All rights reserved. |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 8 | |
| 9 | This software is provided "as is," without warranty of any kind, |
| 10 | express or implied. In no event shall the author or contributors |
| 11 | be held liable for any damages arising in any way from the use of |
| 12 | this software. |
| 13 | |
| 14 | The contents of this file are DUAL-LICENSED. You may modify and/or |
| 15 | redistribute this software according to the terms of one of the |
| 16 | following two licenses (at your option): |
| 17 | |
| 18 | |
| 19 | LICENSE 1 ("BSD-like with advertising clause"): |
| 20 | |
| 21 | Permission is granted to anyone to use this software for any purpose, |
| 22 | including commercial applications, and to alter it and redistribute |
| 23 | it freely, subject to the following restrictions: |
| 24 | |
| 25 | 1. Redistributions of source code must retain the above copyright |
| 26 | notice, disclaimer, and this list of conditions. |
| 27 | 2. Redistributions in binary form must reproduce the above copyright |
| 28 | notice, disclaimer, and this list of conditions in the documenta- |
| 29 | tion and/or other materials provided with the distribution. |
| 30 | 3. All advertising materials mentioning features or use of this |
| 31 | software must display the following acknowledgment: |
| 32 | |
| 33 | This product includes software developed by Greg Roelofs |
| 34 | and contributors for the book, "PNG: The Definitive Guide," |
| 35 | published by O'Reilly and Associates. |
| 36 | |
| 37 | |
| 38 | LICENSE 2 (GNU GPL v2 or later): |
| 39 | |
| 40 | This program is free software; you can redistribute it and/or modify |
| 41 | it under the terms of the GNU General Public License as published by |
| 42 | the Free Software Foundation; either version 2 of the License, or |
| 43 | (at your option) any later version. |
| 44 | |
| 45 | This program is distributed in the hope that it will be useful, |
| 46 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 47 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 48 | GNU General Public License for more details. |
| 49 | |
| 50 | You should have received a copy of the GNU General Public License |
| 51 | along with this program; if not, write to the Free Software Foundation, |
| 52 | Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| 53 | |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame] | 54 | --------------------------------------------------------------------------- |
| 55 | |
| 56 | Changelog: |
| 57 | %RDATE% - Check return value of png_get_bKGD() (Glenn R-P) |
| 58 | |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 59 | ---------------------------------------------------------------------------*/ |
| 60 | |
| 61 | |
| 62 | #include <stdlib.h> /* for exit() prototype */ |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 63 | #include <setjmp.h> |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 64 | |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 65 | #include <zlib.h> |
| 66 | #include "png.h" /* libpng header from the local directory */ |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 67 | #include "readpng2.h" /* typedefs, common macros, public prototypes */ |
| 68 | |
| 69 | |
| 70 | /* local prototypes */ |
| 71 | |
| 72 | static void readpng2_info_callback(png_structp png_ptr, png_infop info_ptr); |
| 73 | static void readpng2_row_callback(png_structp png_ptr, png_bytep new_row, |
| 74 | png_uint_32 row_num, int pass); |
| 75 | static void readpng2_end_callback(png_structp png_ptr, png_infop info_ptr); |
| 76 | static void readpng2_error_handler(png_structp png_ptr, png_const_charp msg); |
Sireesh Tripurari | b478e66 | 2014-05-09 15:15:10 +0530 | [diff] [blame] | 77 | static void readpng2_warning_handler(png_structp png_ptr, png_const_charp msg); |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 78 | |
| 79 | |
| 80 | |
| 81 | |
| 82 | void readpng2_version_info(void) |
| 83 | { |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 84 | fprintf(stderr, " Compiled with libpng %s; using libpng %s\n", |
| 85 | PNG_LIBPNG_VER_STRING, png_libpng_ver); |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 86 | |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 87 | fprintf(stderr, " and with zlib %s; using zlib %s.\n", |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 88 | ZLIB_VERSION, zlib_version); |
| 89 | } |
| 90 | |
| 91 | |
| 92 | |
| 93 | |
| 94 | int readpng2_check_sig(uch *sig, int num) |
| 95 | { |
Patrick Scott | 5f6bd84 | 2010-06-28 16:55:16 -0400 | [diff] [blame] | 96 | return !png_sig_cmp(sig, 0, num); |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 97 | } |
| 98 | |
| 99 | |
| 100 | |
| 101 | |
| 102 | /* returns 0 for success, 2 for libpng problem, 4 for out of memory */ |
| 103 | |
| 104 | int readpng2_init(mainprog_info *mainprog_ptr) |
| 105 | { |
| 106 | png_structp png_ptr; /* note: temporary variables! */ |
| 107 | png_infop info_ptr; |
| 108 | |
| 109 | |
| 110 | /* could also replace libpng warning-handler (final NULL), but no need: */ |
| 111 | |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame] | 112 | png_ptr = png_create_read_struct(png_get_libpng_ver(NULL), mainprog_ptr, |
Sireesh Tripurari | b478e66 | 2014-05-09 15:15:10 +0530 | [diff] [blame] | 113 | readpng2_error_handler, readpng2_warning_handler); |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 114 | if (!png_ptr) |
| 115 | return 4; /* out of memory */ |
| 116 | |
| 117 | info_ptr = png_create_info_struct(png_ptr); |
| 118 | if (!info_ptr) { |
| 119 | png_destroy_read_struct(&png_ptr, NULL, NULL); |
| 120 | return 4; /* out of memory */ |
| 121 | } |
| 122 | |
| 123 | |
| 124 | /* we could create a second info struct here (end_info), but it's only |
| 125 | * useful if we want to keep pre- and post-IDAT chunk info separated |
| 126 | * (mainly for PNG-aware image editors and converters) */ |
| 127 | |
| 128 | |
| 129 | /* setjmp() must be called in every function that calls a PNG-reading |
| 130 | * libpng function, unless an alternate error handler was installed-- |
| 131 | * but compatible error handlers must either use longjmp() themselves |
| 132 | * (as in this program) or exit immediately, so here we are: */ |
| 133 | |
| 134 | if (setjmp(mainprog_ptr->jmpbuf)) { |
| 135 | png_destroy_read_struct(&png_ptr, &info_ptr, NULL); |
| 136 | return 2; |
| 137 | } |
| 138 | |
| 139 | |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 140 | #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 141 | /* prepare the reader to ignore all recognized chunks whose data won't be |
| 142 | * used, i.e., all chunks recognized by libpng except for IHDR, PLTE, IDAT, |
| 143 | * IEND, tRNS, bKGD, gAMA, and sRGB (small performance improvement) */ |
| 144 | { |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 145 | /* These byte strings were copied from png.h. If a future version |
| 146 | * of readpng2.c recognizes more chunks, add them to this list. |
| 147 | */ |
| 148 | static PNG_CONST png_byte chunks_to_process[] = { |
| 149 | 98, 75, 71, 68, '\0', /* bKGD */ |
| 150 | 103, 65, 77, 65, '\0', /* gAMA */ |
| 151 | 115, 82, 71, 66, '\0', /* sRGB */ |
| 152 | }; |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 153 | |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 154 | /* Ignore all chunks except for IHDR, PLTE, tRNS, IDAT, and IEND */ |
| 155 | png_set_keep_unknown_chunks(png_ptr, -1 /* PNG_HANDLE_CHUNK_NEVER */, |
| 156 | NULL, -1); |
| 157 | |
| 158 | /* But do not ignore chunks in the "chunks_to_process" list */ |
| 159 | png_set_keep_unknown_chunks(png_ptr, |
| 160 | 0 /* PNG_HANDLE_CHUNK_AS_DEFAULT */, chunks_to_process, |
| 161 | sizeof(chunks_to_process)/5); |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 162 | } |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 163 | #endif /* PNG_HANDLE_AS_UNKNOWN_SUPPORTED */ |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 164 | |
| 165 | |
| 166 | /* instead of doing png_init_io() here, now we set up our callback |
| 167 | * functions for progressive decoding */ |
| 168 | |
| 169 | png_set_progressive_read_fn(png_ptr, mainprog_ptr, |
| 170 | readpng2_info_callback, readpng2_row_callback, readpng2_end_callback); |
| 171 | |
| 172 | |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 173 | /* make sure we save our pointers for use in readpng2_decode_data() */ |
| 174 | |
| 175 | mainprog_ptr->png_ptr = png_ptr; |
| 176 | mainprog_ptr->info_ptr = info_ptr; |
| 177 | |
| 178 | |
| 179 | /* and that's all there is to initialization */ |
| 180 | |
| 181 | return 0; |
| 182 | } |
| 183 | |
| 184 | |
| 185 | |
| 186 | |
| 187 | /* returns 0 for success, 2 for libpng (longjmp) problem */ |
| 188 | |
| 189 | int readpng2_decode_data(mainprog_info *mainprog_ptr, uch *rawbuf, ulg length) |
| 190 | { |
| 191 | png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr; |
| 192 | png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr; |
| 193 | |
| 194 | |
| 195 | /* setjmp() must be called in every function that calls a PNG-reading |
| 196 | * libpng function */ |
| 197 | |
| 198 | if (setjmp(mainprog_ptr->jmpbuf)) { |
| 199 | png_destroy_read_struct(&png_ptr, &info_ptr, NULL); |
| 200 | mainprog_ptr->png_ptr = NULL; |
| 201 | mainprog_ptr->info_ptr = NULL; |
| 202 | return 2; |
| 203 | } |
| 204 | |
| 205 | |
| 206 | /* hand off the next chunk of input data to libpng for decoding */ |
| 207 | |
| 208 | png_process_data(png_ptr, info_ptr, rawbuf, length); |
| 209 | |
| 210 | return 0; |
| 211 | } |
| 212 | |
| 213 | |
| 214 | |
| 215 | |
| 216 | static void readpng2_info_callback(png_structp png_ptr, png_infop info_ptr) |
| 217 | { |
| 218 | mainprog_info *mainprog_ptr; |
| 219 | int color_type, bit_depth; |
Patrick Scott | 5f6bd84 | 2010-06-28 16:55:16 -0400 | [diff] [blame] | 220 | png_uint_32 width, height; |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 221 | #ifdef PNG_FLOATING_POINT_SUPPORTED |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 222 | double gamma; |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 223 | #else |
| 224 | png_fixed_point gamma; |
| 225 | #endif |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 226 | |
| 227 | |
| 228 | /* setjmp() doesn't make sense here, because we'd either have to exit(), |
| 229 | * longjmp() ourselves, or return control to libpng, which doesn't want |
| 230 | * to see us again. By not doing anything here, libpng will instead jump |
| 231 | * to readpng2_decode_data(), which can return an error value to the main |
| 232 | * program. */ |
| 233 | |
| 234 | |
| 235 | /* retrieve the pointer to our special-purpose struct, using the png_ptr |
| 236 | * that libpng passed back to us (i.e., not a global this time--there's |
| 237 | * no real difference for a single image, but for a multithreaded browser |
| 238 | * decoding several PNG images at the same time, one needs to avoid mixing |
| 239 | * up different images' structs) */ |
| 240 | |
| 241 | mainprog_ptr = png_get_progressive_ptr(png_ptr); |
| 242 | |
| 243 | if (mainprog_ptr == NULL) { /* we be hosed */ |
| 244 | fprintf(stderr, |
| 245 | "readpng2 error: main struct not recoverable in info_callback.\n"); |
| 246 | fflush(stderr); |
| 247 | return; |
| 248 | /* |
| 249 | * Alternatively, we could call our error-handler just like libpng |
| 250 | * does, which would effectively terminate the program. Since this |
| 251 | * can only happen if png_ptr gets redirected somewhere odd or the |
| 252 | * main PNG struct gets wiped, we're probably toast anyway. (If |
| 253 | * png_ptr itself is NULL, we would not have been called.) |
| 254 | */ |
| 255 | } |
| 256 | |
| 257 | |
| 258 | /* this is just like in the non-progressive case */ |
| 259 | |
Patrick Scott | 5f6bd84 | 2010-06-28 16:55:16 -0400 | [diff] [blame] | 260 | png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, |
| 261 | NULL, NULL, NULL); |
| 262 | mainprog_ptr->width = (ulg)width; |
| 263 | mainprog_ptr->height = (ulg)height; |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 264 | |
| 265 | |
| 266 | /* since we know we've read all of the PNG file's "header" (i.e., up |
| 267 | * to IDAT), we can check for a background color here */ |
| 268 | |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame] | 269 | if (mainprog_ptr->need_bgcolor) |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 270 | { |
| 271 | png_color_16p pBackground; |
| 272 | |
| 273 | /* it is not obvious from the libpng documentation, but this function |
| 274 | * takes a pointer to a pointer, and it always returns valid red, |
| 275 | * green and blue values, regardless of color_type: */ |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame] | 276 | if (png_get_bKGD(png_ptr, info_ptr, &pBackground)) |
| 277 | { |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 278 | |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame] | 279 | /* however, it always returns the raw bKGD data, regardless of any |
| 280 | * bit-depth transformations, so check depth and adjust if necessary |
| 281 | */ |
| 282 | if (bit_depth == 16) { |
| 283 | mainprog_ptr->bg_red = pBackground->red >> 8; |
| 284 | mainprog_ptr->bg_green = pBackground->green >> 8; |
| 285 | mainprog_ptr->bg_blue = pBackground->blue >> 8; |
| 286 | } else if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) { |
| 287 | if (bit_depth == 1) |
| 288 | mainprog_ptr->bg_red = mainprog_ptr->bg_green = |
| 289 | mainprog_ptr->bg_blue = pBackground->gray? 255 : 0; |
| 290 | else if (bit_depth == 2) |
| 291 | mainprog_ptr->bg_red = mainprog_ptr->bg_green = |
| 292 | mainprog_ptr->bg_blue = (255/3) * pBackground->gray; |
| 293 | else /* bit_depth == 4 */ |
| 294 | mainprog_ptr->bg_red = mainprog_ptr->bg_green = |
| 295 | mainprog_ptr->bg_blue = (255/15) * pBackground->gray; |
| 296 | } else { |
| 297 | mainprog_ptr->bg_red = (uch)pBackground->red; |
| 298 | mainprog_ptr->bg_green = (uch)pBackground->green; |
| 299 | mainprog_ptr->bg_blue = (uch)pBackground->blue; |
| 300 | } |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 301 | } |
| 302 | } |
| 303 | |
| 304 | |
| 305 | /* as before, let libpng expand palette images to RGB, low-bit-depth |
| 306 | * grayscale images to 8 bits, transparency chunks to full alpha channel; |
| 307 | * strip 16-bit-per-sample images to 8 bits per sample; and convert |
| 308 | * grayscale to RGB[A] */ |
| 309 | |
| 310 | if (color_type == PNG_COLOR_TYPE_PALETTE) |
| 311 | png_set_expand(png_ptr); |
| 312 | if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8) |
| 313 | png_set_expand(png_ptr); |
| 314 | if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) |
| 315 | png_set_expand(png_ptr); |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 316 | #ifdef PNG_READ_16_TO_8_SUPPORTED |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 317 | if (bit_depth == 16) |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 318 | # ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED |
| 319 | png_set_scale_16(png_ptr); |
| 320 | # else |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 321 | png_set_strip_16(png_ptr); |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 322 | # endif |
| 323 | #endif |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 324 | if (color_type == PNG_COLOR_TYPE_GRAY || |
| 325 | color_type == PNG_COLOR_TYPE_GRAY_ALPHA) |
| 326 | png_set_gray_to_rgb(png_ptr); |
| 327 | |
| 328 | |
| 329 | /* Unlike the basic viewer, which was designed to operate on local files, |
| 330 | * this program is intended to simulate a web browser--even though we |
| 331 | * actually read from a local file, too. But because we are pretending |
| 332 | * that most of the images originate on the Internet, we follow the recom- |
| 333 | * mendation of the sRGB proposal and treat unlabelled images (no gAMA |
| 334 | * chunk) as existing in the sRGB color space. That is, we assume that |
| 335 | * such images have a file gamma of 0.45455, which corresponds to a PC-like |
| 336 | * display system. This change in assumptions will have no effect on a |
| 337 | * PC-like system, but on a Mac, SGI, NeXT or other system with a non- |
| 338 | * identity lookup table, it will darken unlabelled images, which effec- |
| 339 | * tively favors images from PC-like systems over those originating on |
| 340 | * the local platform. Note that mainprog_ptr->display_exponent is the |
| 341 | * "gamma" value for the entire display system, i.e., the product of |
| 342 | * LUT_exponent and CRT_exponent. */ |
| 343 | |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 344 | #ifdef PNG_FLOATING_POINT_SUPPORTED |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 345 | if (png_get_gAMA(png_ptr, info_ptr, &gamma)) |
| 346 | png_set_gamma(png_ptr, mainprog_ptr->display_exponent, gamma); |
| 347 | else |
| 348 | png_set_gamma(png_ptr, mainprog_ptr->display_exponent, 0.45455); |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 349 | #else |
| 350 | if (png_get_gAMA_fixed(png_ptr, info_ptr, &gamma)) |
| 351 | png_set_gamma_fixed(png_ptr, |
| 352 | (png_fixed_point)(100000*mainprog_ptr->display_exponent+.5), gamma); |
| 353 | else |
| 354 | png_set_gamma_fixed(png_ptr, |
| 355 | (png_fixed_point)(100000*mainprog_ptr->display_exponent+.5), 45455); |
| 356 | #endif |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 357 | |
| 358 | /* we'll let libpng expand interlaced images, too */ |
| 359 | |
| 360 | mainprog_ptr->passes = png_set_interlace_handling(png_ptr); |
| 361 | |
| 362 | |
| 363 | /* all transformations have been registered; now update info_ptr data and |
| 364 | * then get rowbytes and channels */ |
| 365 | |
| 366 | png_read_update_info(png_ptr, info_ptr); |
| 367 | |
| 368 | mainprog_ptr->rowbytes = (int)png_get_rowbytes(png_ptr, info_ptr); |
| 369 | mainprog_ptr->channels = png_get_channels(png_ptr, info_ptr); |
| 370 | |
| 371 | |
| 372 | /* Call the main program to allocate memory for the image buffer and |
| 373 | * initialize windows and whatnot. (The old-style function-pointer |
| 374 | * invocation is used for compatibility with a few supposedly ANSI |
| 375 | * compilers that nevertheless barf on "fn_ptr()"-style syntax.) */ |
| 376 | |
| 377 | (*mainprog_ptr->mainprog_init)(); |
| 378 | |
| 379 | |
| 380 | /* and that takes care of initialization */ |
| 381 | |
| 382 | return; |
| 383 | } |
| 384 | |
| 385 | |
| 386 | |
| 387 | |
| 388 | |
| 389 | static void readpng2_row_callback(png_structp png_ptr, png_bytep new_row, |
| 390 | png_uint_32 row_num, int pass) |
| 391 | { |
| 392 | mainprog_info *mainprog_ptr; |
| 393 | |
| 394 | |
| 395 | /* first check whether the row differs from the previous pass; if not, |
| 396 | * nothing to combine or display */ |
| 397 | |
| 398 | if (!new_row) |
| 399 | return; |
| 400 | |
| 401 | |
| 402 | /* retrieve the pointer to our special-purpose struct so we can access |
| 403 | * the old rows and image-display callback function */ |
| 404 | |
| 405 | mainprog_ptr = png_get_progressive_ptr(png_ptr); |
| 406 | |
| 407 | |
| 408 | /* save the pass number for optional use by the front end */ |
| 409 | |
| 410 | mainprog_ptr->pass = pass; |
| 411 | |
| 412 | |
| 413 | /* have libpng either combine the new row data with the existing row data |
| 414 | * from previous passes (if interlaced) or else just copy the new row |
| 415 | * into the main program's image buffer */ |
| 416 | |
| 417 | png_progressive_combine_row(png_ptr, mainprog_ptr->row_pointers[row_num], |
| 418 | new_row); |
| 419 | |
| 420 | |
| 421 | /* finally, call the display routine in the main program with the number |
| 422 | * of the row we just updated */ |
| 423 | |
| 424 | (*mainprog_ptr->mainprog_display_row)(row_num); |
| 425 | |
| 426 | |
| 427 | /* and we're ready for more */ |
| 428 | |
| 429 | return; |
| 430 | } |
| 431 | |
| 432 | |
| 433 | |
| 434 | |
| 435 | |
| 436 | static void readpng2_end_callback(png_structp png_ptr, png_infop info_ptr) |
| 437 | { |
| 438 | mainprog_info *mainprog_ptr; |
| 439 | |
| 440 | |
| 441 | /* retrieve the pointer to our special-purpose struct */ |
| 442 | |
| 443 | mainprog_ptr = png_get_progressive_ptr(png_ptr); |
| 444 | |
| 445 | |
| 446 | /* let the main program know that it should flush any buffered image |
| 447 | * data to the display now and set a "done" flag or whatever, but note |
| 448 | * that it SHOULD NOT DESTROY THE PNG STRUCTS YET--in other words, do |
| 449 | * NOT call readpng2_cleanup() either here or in the finish_display() |
| 450 | * routine; wait until control returns to the main program via |
| 451 | * readpng2_decode_data() */ |
| 452 | |
| 453 | (*mainprog_ptr->mainprog_finish_display)(); |
| 454 | |
| 455 | |
| 456 | /* all done */ |
| 457 | |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame] | 458 | (void)info_ptr; /* Unused */ |
| 459 | |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 460 | return; |
| 461 | } |
| 462 | |
| 463 | |
| 464 | |
| 465 | |
| 466 | |
| 467 | void readpng2_cleanup(mainprog_info *mainprog_ptr) |
| 468 | { |
| 469 | png_structp png_ptr = (png_structp)mainprog_ptr->png_ptr; |
| 470 | png_infop info_ptr = (png_infop)mainprog_ptr->info_ptr; |
| 471 | |
| 472 | if (png_ptr && info_ptr) |
| 473 | png_destroy_read_struct(&png_ptr, &info_ptr, NULL); |
| 474 | |
| 475 | mainprog_ptr->png_ptr = NULL; |
| 476 | mainprog_ptr->info_ptr = NULL; |
| 477 | } |
| 478 | |
| 479 | |
Sireesh Tripurari | b478e66 | 2014-05-09 15:15:10 +0530 | [diff] [blame] | 480 | static void readpng2_warning_handler(png_structp png_ptr, png_const_charp msg) |
| 481 | { |
| 482 | fprintf(stderr, "readpng2 libpng warning: %s\n", msg); |
| 483 | fflush(stderr); |
Matt Sarett | 96be908 | 2016-05-03 13:29:54 -0400 | [diff] [blame] | 484 | (void)png_ptr; /* Unused */ |
Sireesh Tripurari | b478e66 | 2014-05-09 15:15:10 +0530 | [diff] [blame] | 485 | } |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 486 | |
| 487 | |
| 488 | static void readpng2_error_handler(png_structp png_ptr, png_const_charp msg) |
| 489 | { |
| 490 | mainprog_info *mainprog_ptr; |
| 491 | |
| 492 | /* This function, aside from the extra step of retrieving the "error |
| 493 | * pointer" (below) and the fact that it exists within the application |
| 494 | * rather than within libpng, is essentially identical to libpng's |
| 495 | * default error handler. The second point is critical: since both |
| 496 | * setjmp() and longjmp() are called from the same code, they are |
| 497 | * guaranteed to have compatible notions of how big a jmp_buf is, |
| 498 | * regardless of whether _BSD_SOURCE or anything else has (or has not) |
| 499 | * been defined. */ |
| 500 | |
| 501 | fprintf(stderr, "readpng2 libpng error: %s\n", msg); |
| 502 | fflush(stderr); |
| 503 | |
| 504 | mainprog_ptr = png_get_error_ptr(png_ptr); |
| 505 | if (mainprog_ptr == NULL) { /* we are completely hosed now */ |
| 506 | fprintf(stderr, |
| 507 | "readpng2 severe error: jmpbuf not recoverable; terminating.\n"); |
| 508 | fflush(stderr); |
| 509 | exit(99); |
| 510 | } |
| 511 | |
Chris Craik | b50c217 | 2013-07-29 15:28:30 -0700 | [diff] [blame] | 512 | /* Now we have our data structure we can use the information in it |
| 513 | * to return control to our own higher level code (all the points |
| 514 | * where 'setjmp' is called in this file.) This will work with other |
| 515 | * error handling mechanisms as well - libpng always calls png_error |
| 516 | * when it can proceed no further, thus, so long as the error handler |
| 517 | * is intercepted, application code can do its own error recovery. |
| 518 | */ |
The Android Open Source Project | 893912b | 2009-03-03 19:30:05 -0800 | [diff] [blame] | 519 | longjmp(mainprog_ptr->jmpbuf, 1); |
| 520 | } |