diff --git a/examples/cwebp.c b/examples/cwebp.c index 47a9c3b5..4004a9ac 100644 --- a/examples/cwebp.c +++ b/examples/cwebp.c @@ -327,7 +327,7 @@ static int ReadPicture(const char* const filename, WebPPicture* const pic, // If no size specified, try to decode it as PNG/JPEG (as appropriate). const InputFileFormat format = GetImageType(in_file); if (format == PNG_) { - ok = ReadPNG(in_file, pic, keep_alpha); + ok = ReadPNG(in_file, pic, keep_alpha, metadata); } else if (format == JPEG_) { ok = ReadJPEG(in_file, pic); } else if (format == TIFF_) { diff --git a/examples/pngdec.c b/examples/pngdec.c index ff984734..a6b271cb 100644 --- a/examples/pngdec.c +++ b/examples/pngdec.c @@ -21,15 +21,173 @@ #include #include "webp/encode.h" +#include "./metadata.h" static void PNGAPI error_function(png_structp png, png_const_charp dummy) { (void)dummy; // remove variable-unused warning longjmp(png_jmpbuf(png), 1); } -int ReadPNG(FILE* in_file, WebPPicture* const pic, int keep_alpha) { +// Converts the NULL terminated 'hexstring' which contains 2-byte character +// representations of hex values to raw data. +// 'hexstring' may contain values consisting of [A-F][a-f][0-9] in pairs, +// e.g., 7af2..., separated by any number of newlines. +// 'expected_length' is the anticipated processed size. +// On success the raw buffer is returned with its length equivalent to +// 'expected_length'. NULL is returned if the processed length is less than +// 'expected_length' or any character aside from those above is encountered. +// The returned buffer must be freed by the caller. +static uint8_t* HexStringToBytes(const char* hexstring, + size_t expected_length) { + const char* src = hexstring; + size_t actual_length = 0; + uint8_t* const raw_data = (uint8_t*)malloc(expected_length); + uint8_t* dst; + + if (raw_data == NULL) return NULL; + + for (dst = raw_data; actual_length < expected_length && *src != '\0'; ++src) { + char* end; + char val[3]; + if (*src == '\n') continue; + val[0] = *src++; + val[1] = *src; + val[2] = '\0'; + *dst++ = (uint8_t)strtol(val, &end, 16); + if (end != val + 2) break; + ++actual_length; + } + + if (actual_length != expected_length) { + free(raw_data); + return NULL; + } + return raw_data; +} + +static int ProcessRawProfile(const char* profile, size_t profile_len, + MetadataPayload* const payload) { + const char* src = profile; + char* end; + int expected_length; + + if (profile == NULL || profile_len == 0) return 0; + + // ImageMagick formats 'raw profiles' as + // '\n\n(%8lu)\n\n'. + if (*src != '\n') { + fprintf(stderr, "Malformed raw profile, expected '\\n' got '\\x%.2X'\n", + *src); + return 0; + } + ++src; + // skip the profile name and extract the length. + while (*src != '\0' && *src++ != '\n') {} + expected_length = (int)strtol(src, &end, 10); + if (*end != '\n') { + fprintf(stderr, "Malformed raw profile, expected '\\n' got '\\x%.2X'\n", + *end); + return 0; + } + ++end; + + // 'end' now points to the profile payload. + payload->bytes = HexStringToBytes(end, expected_length); + if (payload->bytes == NULL) return 0; + payload->size = expected_length; + return 1; +} + +static const struct { + const char* name; + int (*process)(const char* profile, size_t profile_len, + MetadataPayload* const payload); + size_t storage_offset; +} kPNGMetadataMap[] = { + // http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/PNG.html#TextualData + // See also: ExifTool on CPAN. + { "Raw profile type exif", ProcessRawProfile, METADATA_OFFSET(exif) }, + { "Raw profile type xmp", ProcessRawProfile, METADATA_OFFSET(xmp) }, + // XMP Specification Part 3, Section 3 #PNG + { "XML:com.adobe.xmp", MetadataCopy, METADATA_OFFSET(xmp) }, + { NULL, NULL, 0 }, +}; + +// Looks for metadata at both the beginning and end of the PNG file, giving +// preference to the head. +// Returns true on success. The caller must use MetadataFree() on 'metadata' in +// all cases. +static int ExtractMetadataFromPNG(png_structp png, + png_infop const head_info, + png_infop const end_info, + Metadata* const metadata) { + int p; + + for (p = 0; p < 2; ++p) { + png_infop const info = (p == 0) ? head_info : end_info; + png_textp text = NULL; + const int num = png_get_text(png, info, &text, NULL); + int i; + // Look for EXIF / XMP metadata. + for (i = 0; i < num; ++i, ++text) { + int j; + for (j = 0; kPNGMetadataMap[j].name != NULL; ++j) { + if (!strcmp(text->key, kPNGMetadataMap[j].name)) { + MetadataPayload* const payload = + (MetadataPayload*)((uint8_t*)metadata + + kPNGMetadataMap[j].storage_offset); + png_size_t text_length; + switch (text->compression) { +#ifdef PNG_iTXt_SUPPORTED + case PNG_ITXT_COMPRESSION_NONE: + case PNG_ITXT_COMPRESSION_zTXt: + text_length = text->itxt_length; + break; +#endif + default: + case PNG_TEXT_COMPRESSION_NONE: + case PNG_TEXT_COMPRESSION_zTXt: + text_length = text->text_length; + break; + } + if (payload->bytes != NULL) { + fprintf(stderr, "Ignoring additional '%s'\n", text->key); + } else if (!kPNGMetadataMap[j].process(text->text, text_length, + payload)) { + fprintf(stderr, "Failed to process: '%s'\n", text->key); + return 0; + } + break; + } + } + } + // Look for an ICC profile. + { + png_charp name; + int comp_type; +#if ((PNG_LIBPNG_VER_MAJOR << 8) | PNG_LIBPNG_VER_MINOR << 0) < \ + ((1 << 8) | (5 << 0)) + png_charp profile; +#else // >= libpng 1.5.0 + png_bytep profile; +#endif + png_uint_32 len; + + if (png_get_iCCP(png, info, + &name, &comp_type, &profile, &len) == PNG_INFO_iCCP) { + if (!MetadataCopy((const char*)profile, len, &metadata->iccp)) return 0; + } + } + } + + return 1; +} + +int ReadPNG(FILE* in_file, WebPPicture* const pic, int keep_alpha, + Metadata* const metadata) { png_structp png; - png_infop info; + png_infop info = NULL; + png_infop end_info = NULL; int color_type, bit_depth, interlaced; int has_alpha; int num_passes; @@ -47,13 +205,16 @@ int ReadPNG(FILE* in_file, WebPPicture* const pic, int keep_alpha) { png_set_error_fn(png, 0, error_function, NULL); if (setjmp(png_jmpbuf(png))) { Error: - png_destroy_read_struct(&png, NULL, NULL); + MetadataFree(metadata); + png_destroy_read_struct(&png, &info, &end_info); free(rgb); 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); @@ -94,8 +255,15 @@ int ReadPNG(FILE* in_file, WebPPicture* const pic, int keep_alpha) { png_read_rows(png, &row, NULL, 1); } } - png_read_end(png, info); - png_destroy_read_struct(&png, &info, NULL); + 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; @@ -103,7 +271,10 @@ int ReadPNG(FILE* in_file, WebPPicture* const pic, int keep_alpha) { : WebPPictureImportRGB(pic, rgb, stride); free(rgb); - if (ok && has_alpha && keep_alpha == 2) { + if (!ok) { + goto Error; + } + if (has_alpha && keep_alpha == 2) { WebPCleanupTransparentArea(pic); } @@ -111,10 +282,12 @@ int ReadPNG(FILE* in_file, WebPPicture* const pic, int keep_alpha) { return ok; } #else // !WEBP_HAVE_PNG -int ReadPNG(FILE* in_file, struct WebPPicture* const pic, int keep_alpha) { +int ReadPNG(FILE* in_file, struct WebPPicture* const pic, int keep_alpha, + struct Metadata* const metadata) { (void)in_file; (void)pic; (void)keep_alpha; + (void)metadata; fprintf(stderr, "PNG support not compiled. Please install the libpng " "development package before building.\n"); return 0; diff --git a/examples/pngdec.h b/examples/pngdec.h index 5cee3ad2..f53f8631 100644 --- a/examples/pngdec.h +++ b/examples/pngdec.h @@ -16,13 +16,15 @@ extern "C" { #endif +struct Metadata; struct WebPPicture; // Reads a PNG from 'in_file', returning the decoded output in 'pic'. // If 'keep_alpha' is true and the PNG has an alpha channel, the output is RGBA // otherwise it will be RGB. // Returns true on success. -int ReadPNG(FILE* in_file, struct WebPPicture* const pic, int keep_alpha); +int ReadPNG(FILE* in_file, struct WebPPicture* const pic, int keep_alpha, + struct Metadata* const metadata); #if defined(__cplusplus) || defined(c_plusplus) } // extern "C"