third_party/jpeg-xl/examples/decode_exif_metadata.cc

   1 // Copyright (c) the JPEG XL Project Authors. All rights reserved.
   2 //
   3 // Use of this source code is governed by a BSD-style
   4 // license that can be found in the LICENSE file.
   5
   6 // This C++ example decodes a JPEG XL image in one shot (all input bytes
   7 // available at once). The example outputs the pixels and color information to a
   8 // floating point image and an ICC profile on disk.
   9
  10 #include <jxl/decode.h>
  11 #include <jxl/decode_cxx.h>
  12 #include <limits.h>
  13 #include <stdint.h>
  14 #include <stdio.h>
  15 #include <string.h>
  16
  17 #include <vector>
  18
  19 bool DecodeJpegXlExif(const uint8_t* jxl, size_t size,
  20                       std::vector<uint8_t>* exif) {
  21   auto dec = JxlDecoderMake(nullptr);
  22
  23   // We're only interested in the Exif boxes in this example, so don't
  24   // subscribe to events related to pixel data.
  25   if (JXL_DEC_SUCCESS != JxlDecoderSubscribeEvents(
  26                              dec.get(), JXL_DEC_BOX | JXL_DEC_BOX_COMPLETE)) {
  27     fprintf(stderr, "JxlDecoderSubscribeEvents failed\n");
  28     return false;
  29   }
  30   bool support_decompression = true;
  31   if (JXL_DEC_SUCCESS != JxlDecoderSetDecompressBoxes(dec.get(), JXL_TRUE)) {
  32     fprintf(stderr,
  33             "NOTE: decompressing brob boxes not supported with the currently "
  34             "used jxl library.\n");
  35     support_decompression = false;
  36   }
  37
  38   JxlDecoderSetInput(dec.get(), jxl, size);
  39   JxlDecoderCloseInput(dec.get());
  40
  41   const constexpr size_t kChunkSize = 65536;
  42   size_t output_pos = 0;
  43
  44   for (;;) {
  45     JxlDecoderStatus status = JxlDecoderProcessInput(dec.get());
  46     if (status == JXL_DEC_ERROR) {
  47       fprintf(stderr, "Decoder error\n");
  48       return false;
  49     } else if (status == JXL_DEC_NEED_MORE_INPUT) {
  50       fprintf(stderr, "Error, already provided all input\n");
  51       return false;
  52     } else if (status == JXL_DEC_BOX) {
  53       if (!exif->empty()) {
  54         size_t remaining = JxlDecoderReleaseBoxBuffer(dec.get());
  55         exif->resize(exif->size() - remaining);
  56         // No need to wait for JXL_DEC_SUCCESS or decode other boxes.
  57         return true;
  58       }
  59       JxlBoxType type;
  60       status = JxlDecoderGetBoxType(dec.get(), type,
  61                                     TO_JXL_BOOL(support_decompression));
  62       if (JXL_DEC_SUCCESS != status) {
  63         fprintf(stderr, "Error, failed to get box type\n");
  64         return false;
  65       }
  66       if (!memcmp(type, "Exif", 4)) {
  67         exif->resize(kChunkSize);
  68         JxlDecoderSetBoxBuffer(dec.get(), exif->data(), exif->size());
  69       }
  70     } else if (status == JXL_DEC_BOX_NEED_MORE_OUTPUT) {
  71       size_t remaining = JxlDecoderReleaseBoxBuffer(dec.get());
  72       output_pos += kChunkSize - remaining;
  73       exif->resize(exif->size() + kChunkSize);
  74       JxlDecoderSetBoxBuffer(dec.get(), exif->data() + output_pos,
  75                              exif->size() - output_pos);
  76     } else if (status == JXL_DEC_BOX_COMPLETE) {
  77       if (!exif->empty()) {
  78         size_t remaining = JxlDecoderReleaseBoxBuffer(dec.get());
  79         exif->resize(exif->size() - remaining);
  80         return true;
  81       }
  82       return true;
  83     } else {
  84       fprintf(stderr, "Unknown decoder status\n");
  85       return false;
  86     }
  87   }
  88 }
  89
  90 bool LoadFile(const char* filename, std::vector<uint8_t>* out) {
  91   FILE* file = fopen(filename, "rb");
  92   if (!file) {
  93     return false;
  94   }
  95
  96   if (fseek(file, 0, SEEK_END) != 0) {
  97     fclose(file);
  98     return false;
  99   }
 100
 101   long size = ftell(file);  // NOLINT
 102   // Avoid invalid file or directory.
 103   if (size >= LONG_MAX || size < 0) {
 104     fclose(file);
 105     return false;
 106   }
 107
 108   if (fseek(file, 0, SEEK_SET) != 0) {
 109     fclose(file);
 110     return false;
 111   }
 112
 113   out->resize(size);
 114   size_t readsize = fread(out->data(), 1, size, file);
 115   if (fclose(file) != 0) {
 116     return false;
 117   }
 118
 119   return readsize == static_cast<size_t>(size);
 120 }
 121
 122 bool WriteFile(const char* filename, const uint8_t* data, size_t size) {
 123   FILE* file = fopen(filename, "wb");
 124   if (!file) {
 125     fprintf(stderr, "Could not open %s for writing", filename);
 126     return false;
 127   }
 128   fwrite(data, 1, size, file);
 129   if (fclose(file) != 0) {
 130     return false;
 131   }
 132   return true;
 133 }
 134
 135 int main(int argc, char* argv[]) {
 136   if (argc != 3) {
 137     fprintf(stderr,
 138             "Usage: %s <jxl> <exif>\n"
 139             "Where:\n"
 140             "  jxl = input JPEG XL image filename\n"
 141             "  exif = output exif filename\n"
 142             "Output files will be overwritten.\n",
 143             argv[0]);
 144     return 1;
 145   }
 146
 147   const char* jxl_filename = argv[1];
 148   const char* exif_filename = argv[2];
 149
 150   std::vector<uint8_t> jxl;
 151   if (!LoadFile(jxl_filename, &jxl)) {
 152     fprintf(stderr, "couldn't load %s\n", jxl_filename);
 153     return 1;
 154   }
 155
 156   std::vector<uint8_t> exif;
 157   if (!DecodeJpegXlExif(jxl.data(), jxl.size(), &exif)) {
 158     fprintf(stderr, "Error while decoding the jxl file\n");
 159     return 1;
 160   }
 161   if (exif.empty()) {
 162     printf("No exif data present in this image\n");
 163   } else {
 164     // TODO(lode): the exif box data contains the 4-byte TIFF header at the
 165     // beginning, check whether this is desired to be part of the output, or
 166     // should be removed.
 167     if (!WriteFile(exif_filename, exif.data(), exif.size())) {
 168       fprintf(stderr, "Error while writing the exif file\n");
 169       return 1;
 170     }
 171     printf("Successfully wrote %s\n", exif_filename);
 172   }
 173   return 0;
 174 }