Method ReadRecord

tensorflow/core/lib/io/record_reader.cc:164–199

}

Status RecordReader::ReadRecord(uint64* offset, string* record) {
  // Position the input stream.
  int64 curr_pos = input_stream_->Tell();
  int64 desired_pos = static_cast<int64>(*offset);
  if (curr_pos > desired_pos || curr_pos < 0 /* EOF */ ||
      (curr_pos == desired_pos && last_read_failed_)) {
    last_read_failed_ = false;
    TF_RETURN_IF_ERROR(input_stream_->Reset());
    TF_RETURN_IF_ERROR(input_stream_->SkipNBytes(desired_pos));
  } else if (curr_pos < desired_pos) {
    TF_RETURN_IF_ERROR(input_stream_->SkipNBytes(desired_pos - curr_pos));
  }
  DCHECK_EQ(desired_pos, input_stream_->Tell());

  // Read header data.
  Status s = ReadChecksummed(*offset, sizeof(uint64), record);
  if (!s.ok()) {
    last_read_failed_ = true;
    return s;
  }
  const uint64 length = core::DecodeFixed64(record->data());

  // Read data
  s = ReadChecksummed(*offset + kHeaderSize, length, record);
  if (!s.ok()) {
    last_read_failed_ = true;
    if (errors::IsOutOfRange(s)) {
      s = errors::DataLoss("truncated record at ", *offset);
    }
    return s;
  }

  *offset += kHeaderSize + length + kFooterSize;
  DCHECK_EQ(*offset, input_stream_->Tell());
  return Status::OK();
}

SequentialRecordReader::SequentialRecordReader(
    RandomAccessFile* file, const RecordReaderOptions& options)