Function ParseEXRHeader

third-party/tinyexr/tinyexr.h:4359–4706

static int ParseEXRHeader(HeaderInfo *info, bool *empty_header,
                          const EXRVersion *version, std::string *err,
                          const unsigned char *buf, size_t size) {
  const char *marker = reinterpret_cast<const char *>(&buf[0]);

  if (empty_header) {
    (*empty_header) = false;
  }

  if (version->multipart) {
    if (size > 0 && marker[0] == '\0') {
      // End of header list.
      if (empty_header) {
        (*empty_header) = true;
      }
      return TINYEXR_SUCCESS;
    }
  }

  // According to the spec, the header of every OpenEXR file must contain at
  // least the following attributes:
  //
  // channels chlist
  // compression compression
  // dataWindow box2i
  // displayWindow box2i
  // lineOrder lineOrder
  // pixelAspectRatio float
  // screenWindowCenter v2f
  // screenWindowWidth float
  bool has_channels = false;
  bool has_compression = false;
  bool has_data_window = false;
  bool has_display_window = false;
  bool has_line_order = false;
  bool has_pixel_aspect_ratio = false;
  bool has_screen_window_center = false;
  bool has_screen_window_width = false;
  bool has_name = false;
  bool has_type = false;

  info->name.clear();
  info->type.clear();

  info->data_window.min_x = 0;
  info->data_window.min_y = 0;
  info->data_window.max_x = 0;
  info->data_window.max_y = 0;
  info->line_order = 0;  // @fixme
  info->display_window.min_x = 0;
  info->display_window.min_y = 0;
  info->display_window.max_x = 0;
  info->display_window.max_y = 0;
  info->screen_window_center[0] = 0.0f;
  info->screen_window_center[1] = 0.0f;
  info->screen_window_width = -1.0f;
  info->pixel_aspect_ratio = -1.0f;