typedef struct rif {
  // "lifV0001"
  // "rifV0001"
  char     magic_num[8]; // Big Endian. UTF-8 Encoded. 6C 69 66 56 30 30 30 31
  uint64_t width;        // Big Endian
  uint8_t  format;
  uint8_t  data[];
} rif_t;

#define RIF_MAGIC_LITTLE {'l', 'i', 'f', 'V', '0', '0', '0', '1'}
#define RIF_MAGIC_BIG    {'r', 'i', 'f', 'V', '0', '0', '0', '1'}

#define RIF_FORMAT_R8G8B8   0
#define RIF_FORMAT_R8G8B8A8 1

// TODO detect endianess - this breaks on big endian systems.
void write_rif_little(char* path, uint32_t width, uint32_t size, uint8_t format, void* data) {
  // TODO is this better than just hardcoding 17?
  const uint32_t header_size = sizeof(rif_t) - sizeof(uint8_t*);
  const uint64_t img_size = header_size + size;
  rif_t* img = malloc(img_size);
  char magic[] = RIF_MAGIC_LITTLE;
  memcpy(&img->magic_num, magic, 8);
  img->width = width;
  img->format = format;
  memcpy(&img->data, data, size);
  FILE* output_file = fopen(path, "w");
  fwrite(img, 1, img_size, output_file);
  free(img);
}