Method LookupHeader

tensorflow/core/util/tensor_bundle/tensor_bundle.cc:1079–1111

}

Status BundleReader::LookupHeader(StringPiece tensor_key, int64 total_bytes) {
  BundleEntryProto entry;
  TF_RETURN_IF_ERROR(GetBundleEntryProto(tensor_key, &entry));
  if (entry.size() != total_bytes) {
    return errors::DataLoss("Invalid size in bundle entry: key ", key(),
        "; stored size ", entry.size(),
        "; expected size ", total_bytes);
  }
  io::InputBuffer* buffered_file = data_[entry.shard_id()];
  if (buffered_file == nullptr) {
    std::unique_ptr<RandomAccessFile> file = nullptr;
    TF_RETURN_IF_ERROR(env_->NewRandomAccessFile(
          DataFilename(prefix_, entry.shard_id(), num_shards_), &file));
    buffered_file =
      new io::InputBuffer(file.release(), 256 << 10 /* 256KB buffer */);
    // The InputBuffer and RandomAccessFile objects are both released in dtor.
    data_[entry.shard_id()] = buffered_file;
  }
  CHECK(buffered_file != nullptr);

  TF_RETURN_IF_ERROR(buffered_file->Seek(entry.offset()));
  if (!DataTypeCanUseMemcpy(entry.dtype())) {
    return errors::DataLoss("segment lookup not support string");
  }
  LookupSegItem seg_item;
  seg_item.entry = entry;
  seg_item.total_size = entry.size();
  seg_item.bytes_read = 0;

  tmp_lookupseg_items_[string(tensor_key)] = seg_item;
  return Status::OK();

}

Status BundleReader::LookupSegment(StringPiece key, size_t buffer_size, char* destination, size_t& real_bytes_read) {
  LookupSegItem& seg_item = tmp_lookupseg_items_[string(key)];