text: // Copyright 2017 The TensorFlow 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.
  // =============================================================================
  #ifndef TENSORFLOW_CONTRIB_BOOSTED_TREES_LIB_UTILS_BATCH_FEATURES_H_
  #define TENSORFLOW_CONTRIB_BOOSTED_TREES_LIB_UTILS_BATCH_FEATURES_H_
  
  #include <vector>
  #include "tensorflow/contrib/boosted_trees/lib/utils/examples_iterable.h"
  #include "tensorflow/core/framework/op_kernel.h"
  #include "tensorflow/core/framework/tensor.h"
  #include "tensorflow/core/framework/tensor_types.h"
  #include "tensorflow/core/platform/macros.h"
  #include "tensorflow/core/util/sparse/sparse_tensor.h"
  
  namespace tensorflow {
  namespace boosted_trees {
  namespace utils {
  
  class BatchFeatures {
   public:
    // Constructs batch features with a fixed batch size.
    explicit BatchFeatures(int64 batch_size) : batch_size_(batch_size) {}
  
    // Disallow copy and assign.
    BatchFeatures(const BatchFeatures& other) = delete;
    BatchFeatures& operator=(const BatchFeatures& other) = delete;
  
    // Method to initialize batch features from op kernel context.
    Status Initialize(std::vector<Tensor> dense_float_features_list,
                      std::vector<Tensor> sparse_float_feature_indices_list,
                      std::vector<Tensor> sparse_float_feature_values_list,
                      std::vector<Tensor> sparse_float_feature_shapes_list,
                      std::vector<Tensor> sparse_int_feature_indices_list,
                      std::vector<Tensor> sparse_int_feature_values_list,
                      std::vector<Tensor> sparse_int_feature_shapes_list);
  
    Status GetFeatureColumnSizes(int64* const num_dense_float_features,
                                 int64* const num_sparse_float_features,
                                 int64* const num_sparse_int_features) const {
      QCHECK_NE(num_dense_float_features, (int64*) nullptr);
      QCHECK_NE(num_sparse_float_features, (int64*) nullptr);
      QCHECK_NE(num_sparse_int_features, (int64*) nullptr);
      *num_dense_float_features = dense_float_feature_columns_.size();
      *num_sparse_float_features = sparse_float_feature_columns_.size();
      *num_sparse_int_features = sparse_int_feature_columns_.size();
      if (*num_dense_float_features == 0 && *num_sparse_float_features == 0 &&
          *num_sparse_int_features == 0) {
        return errors::FailedPrecondition("Not initialized yet.");
      }
      return Status::OK();
    }
  
    // Creates an example iterable for the requested slice.
    ExamplesIterable examples_iterable(int64 example_start,
                                       int64 example_end) const {
      QCHECK(example_start >= 0 && example_end >= 0);
      QCHECK(example_start < batch_size_ && example_end <= batch_size_);
      return ExamplesIterable(
          dense_float_feature_columns_, sparse_float_feature_columns_,
          sparse_int_feature_columns_, example_start, example_end);
    }
  
    // Returns the fixed batch size.
    int64 batch_size() const { return batch_size_; }
  
   private:
    // Total number of examples in the batch.
    const int64 batch_size_;
  
    // Dense float feature columns.
    std::vector<Tensor> dense_float_feature_columns_;
  
    // Sparse float feature columns.
    std::vector<sparse::SparseTensor> sparse_float_feature_columns_;
  
    // Sparse int feature columns.
    std::vector<sparse::SparseTensor> sparse_int_feature_columns_;
  };
  
  }  // namespace utils
  }  // namespace boosted_trees
  }  // namespace tensorflow
  
  #endif  // TENSORFLOW_CONTRIB_BOOSTED_TREES_LIB_UTILS_BATCH_FEATURES_H_
  