Function ClassifyFileFormat

tensorflow/core/kernels/decode_image_op.cc:45–51

Classify the contents of a file based on starting bytes (the magic number).

// Classify the contents of a file based on starting bytes (the magic number).
FileFormat ClassifyFileFormat(StringPiece data) {
  // The 4th byte of JPEG is '\xe0' or '\xe1', so check just the first three
  if (absl::StartsWith(data, "\xff\xd8\xff")) return kJpgFormat;
  if (absl::StartsWith(data, "\x89PNG\r\n\x1a\n")) return kPngFormat;
  if (absl::StartsWith(data, "\x47\x49\x46\x38")) return kGifFormat;
  return kUnknownFormat;
}

string FileFormatString(FileFormat magic, StringPiece data) {
  switch (magic) {