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