int ReadPNG(const uint8_t* const data, size_t data_size, struct WebPPicture* const pic, int keep_alpha, struct Metadata* const metadata) { volatile png_structp png = NULL; volatile png_infop info = NULL; volatile png_infop end_info = NULL; PNGReadContext context = { NULL, 0, 0 }; int color_type, bit_depth, interlaced; int has_alpha; int num_passes; int p; volatile int ok = 0; png_uint_32 width, height, y; int64_t stride; uint8_t* volatile rgb = NULL; if (data == NULL || data_size == 0 || pic == NULL) return 0; context.data = data; context.data_size = data_size; png = png_create_read_struct_2(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL, NULL, MallocFunc, FreeFunc); if (png == NULL) goto End; png_set_error_fn(png, 0, error_function, NULL); if (setjmp(png_jmpbuf(png))) { Error: MetadataFree(metadata); goto End; } info = png_create_info_struct(png); if (info == NULL) goto Error; end_info = png_create_info_struct(png); if (end_info == NULL) goto Error; png_set_read_fn(png, &context, ReadFunc); png_read_info(png, info); if (!png_get_IHDR(png, info, &width, &height, &bit_depth, &color_type, &interlaced, NULL, NULL)) goto Error; png_set_strip_16(png); png_set_packing(png); if (color_type == PNG_COLOR_TYPE_PALETTE) { png_set_palette_to_rgb(png); } if (color_type == PNG_COLOR_TYPE_GRAY || color_type == PNG_COLOR_TYPE_GRAY_ALPHA) { if (bit_depth < 8) { png_set_expand_gray_1_2_4_to_8(png); } png_set_gray_to_rgb(png); } if (png_get_valid(png, info, PNG_INFO_tRNS)) { png_set_tRNS_to_alpha(png); has_alpha = 1; } else { has_alpha = !!(color_type & PNG_COLOR_MASK_ALPHA); } // Apply gamma correction if needed. { double image_gamma = 1 / 2.2, screen_gamma = 2.2; int srgb_intent; if (png_get_sRGB(png, info, &srgb_intent) || png_get_gAMA(png, info, &image_gamma)) { png_set_gamma(png, screen_gamma, image_gamma); } } if (!keep_alpha) { png_set_strip_alpha(png); has_alpha = 0; } num_passes = png_set_interlace_handling(png); png_read_update_info(png, info); stride = (int64_t)(has_alpha ? 4 : 3) * width * sizeof(*rgb); if (stride != (int)stride || !ImgIoUtilCheckSizeArgumentsOverflow(stride, height)) { goto Error; } rgb = (uint8_t*)malloc((size_t)stride * height); if (rgb == NULL) goto Error; for (p = 0; p < num_passes; ++p) { png_bytep row = rgb; for (y = 0; y < height; ++y) { png_read_rows(png, &row, NULL, 1); row += stride; } } png_read_end(png, end_info); if (metadata != NULL && !ExtractMetadataFromPNG(png, info, end_info, metadata)) { fprintf(stderr, "Error extracting PNG metadata!\n"); goto Error; } pic->width = (int)width; pic->height = (int)height; ok = has_alpha ? WebPPictureImportRGBA(pic, rgb, (int)stride) : WebPPictureImportRGB(pic, rgb, (int)stride); if (!ok) { goto Error; } End: if (png != NULL) { png_destroy_read_struct((png_structpp)&png, (png_infopp)&info, (png_infopp)&end_info); } free(rgb); return ok; }
int ReadPNG(FILE* in_file, WebPPicture* const pic, int keep_alpha, Metadata* const metadata) { png_structp png; png_infop info = NULL; png_infop end_info = NULL; int color_type, bit_depth, interlaced; int has_alpha; int num_passes; int p; int ok = 0; png_uint_32 width, height, y; int stride; uint8_t* rgb = NULL; png = png_create_read_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0); if (png == NULL) { goto End; } png_set_error_fn(png, 0, error_function, NULL); if (setjmp(png_jmpbuf(png))) { Error: MetadataFree(metadata); png_destroy_read_struct(&png, &info, &end_info); goto End; } info = png_create_info_struct(png); if (info == NULL) goto Error; end_info = png_create_info_struct(png); if (end_info == NULL) goto Error; png_init_io(png, in_file); png_read_info(png, info); if (!png_get_IHDR(png, info, &width, &height, &bit_depth, &color_type, &interlaced, NULL, NULL)) goto Error; png_set_strip_16(png); png_set_packing(png); if (color_type == PNG_COLOR_TYPE_PALETTE) png_set_palette_to_rgb(png); if (color_type == PNG_COLOR_TYPE_GRAY || color_type == PNG_COLOR_TYPE_GRAY_ALPHA) { if (bit_depth < 8) { png_set_expand_gray_1_2_4_to_8(png); } png_set_gray_to_rgb(png); } if (png_get_valid(png, info, PNG_INFO_tRNS)) { png_set_tRNS_to_alpha(png); has_alpha = 1; } else { has_alpha = !!(color_type & PNG_COLOR_MASK_ALPHA); } if (!keep_alpha) { png_set_strip_alpha(png); has_alpha = 0; } num_passes = png_set_interlace_handling(png); png_read_update_info(png, info); stride = (has_alpha ? 4 : 3) * width * sizeof(*rgb); rgb = (uint8_t*)malloc(stride * height); if (rgb == NULL) goto Error; for (p = 0; p < num_passes; ++p) { for (y = 0; y < height; ++y) { png_bytep row = rgb + y * stride; png_read_rows(png, &row, NULL, 1); } } png_read_end(png, end_info); if (metadata != NULL && !ExtractMetadataFromPNG(png, info, end_info, metadata)) { fprintf(stderr, "Error extracting PNG metadata!\n"); goto Error; } png_destroy_read_struct(&png, &info, &end_info); pic->width = width; pic->height = height; ok = has_alpha ? WebPPictureImportRGBA(pic, rgb, stride) : WebPPictureImportRGB(pic, rgb, stride); if (!ok) { goto Error; } End: free(rgb); return ok; }