Function LoadMultiChannelEXR

SampleFramework12/v1.00/TinyEXR.cpp:7064–7367

}

int LoadMultiChannelEXR(EXRImage *exrImage, const char *filename,
                        const char **err) {
  if (exrImage == NULL) {
    if (err) {
      (*err) = "Invalid argument.";
    }
    return -1;
  }

  FILE *fp = fopen(filename, "rb");
  if (!fp) {
    if (err) {
      (*err) = "Cannot read file.";
    }
    return -1;
  }

  size_t filesize;
  // Compute size
  fseek(fp, 0, SEEK_END);
  filesize = ftell(fp);
  fseek(fp, 0, SEEK_SET);

  std::vector<char> buf(filesize); // @todo { use mmap }
  {
    size_t ret;
    ret = fread(&buf[0], 1, filesize, fp);
    assert(ret == filesize);
    fclose(fp);
  }

  const char *head = &buf[0];
  const char *marker = &buf[0];

  // Header check.
  {
    const char header[] = {0x76, 0x2f, 0x31, 0x01};

    if (memcmp(marker, header, 4) != 0) {
      if (err) {
        (*err) = "Header mismatch.";
      }
      return -3;
    }
    marker += 4;
  }

  // Version, scanline.
  {
    // must be [2, 0, 0, 0]
    if (marker[0] != 2 || marker[1] != 0 || marker[2] != 0 || marker[3] != 0) {
      if (err) {
        (*err) = "Unsupported version or scanline.";
      }
      return -4;
    }

    marker += 4;