// Copyright (c) 2019 PaddlePaddle Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "paddle/fluid/operators/reader/compose_reader.h"

namespace paddle {
namespace operators {
namespace reader {

ComposeReader::ComposeReader(
    const std::vector<std::shared_ptr<framework::ReaderBase>> &readers)
    : framework::MultiDecoratedReader(readers) {}

void ComposeReader::ReadNext(std::vector<framework::LoDTensor> *out) {
  out->clear();
  std::vector<framework::LoDTensor> each_ret;
  for (auto &r : readers_) {
    r->ReadNext(&each_ret);
    out->reserve(out->size() + each_ret.size());
    for (auto &data : each_ret) {
      out->emplace_back(std::move(data));
    }
  }
}

}  // namespace reader
}  // namespace operators
}  // namespace paddle