text: /*
   * Copyright 2019 The libgav1 Authors
   *
   * 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 LIBGAV1_SRC_UTILS_BLOCK_PARAMETERS_HOLDER_H_
  #define LIBGAV1_SRC_UTILS_BLOCK_PARAMETERS_HOLDER_H_
  
  #include <memory>
  
  #include "src/utils/array_2d.h"
  #include "src/utils/compiler_attributes.h"
  #include "src/utils/constants.h"
  #include "src/utils/parameter_tree.h"
  #include "src/utils/types.h"
  
  namespace libgav1 {
  
  // Holds a 2D array of |ParameterTree| objects. Each tree stores the parameters
  // corresponding to a superblock.
  class BlockParametersHolder {
   public:
    BlockParametersHolder() = default;
  
    // Not copyable or movable.
    BlockParametersHolder(const BlockParametersHolder&) = delete;
    BlockParametersHolder& operator=(const BlockParametersHolder&) = delete;
  
    // If |use_128x128_superblock| is true, 128x128 superblocks will be used,
    // otherwise 64x64 superblocks will be used.
    LIBGAV1_MUST_USE_RESULT bool Reset(int rows4x4, int columns4x4,
                                       bool use_128x128_superblock);
  
    // Finds the BlockParameters corresponding to |row4x4| and |column4x4|. This
    // is done as a simple look up of the |block_parameters_cache_| matrix.
    // Returns nullptr if the BlockParameters cannot be found.
    BlockParameters* Find(int row4x4, int column4x4) const {
      return block_parameters_cache_[row4x4][column4x4];
    }
  
    BlockParameters** Address(int row4x4, int column4x4) {
      return block_parameters_cache_.data() + row4x4 * columns4x4_ + column4x4;
    }
  
    BlockParameters* const* Address(int row4x4, int column4x4) const {
      return block_parameters_cache_.data() + row4x4 * columns4x4_ + column4x4;
    }
  
    int columns4x4() const { return columns4x4_; }
  
    // Returns the ParameterTree corresponding to superblock starting at (|row|,
    // |column|).
    ParameterTree* Tree(int row, int column) { return trees_[row][column].get(); }
  
    // Fills the cache matrix for the block starting at |row4x4|, |column4x4| of
    // size |block_size| with the pointer |bp|.
    void FillCache(int row4x4, int column4x4, BlockSize block_size,
                   BlockParameters* bp);
  
   private:
    int rows4x4_ = 0;
    int columns4x4_ = 0;
    bool use_128x128_superblock_ = false;
    Array2D<std::unique_ptr<ParameterTree>> trees_;
  
    // This is a 2d array of size |rows4x4_| * |columns4x4_|. This is filled in by
    // FillCache() and used by Find() to perform look ups using exactly one look
    // up (instead of traversing the entire tree).
    Array2D<BlockParameters*> block_parameters_cache_;
  };
  
  }  // namespace libgav1
  
  #endif  // LIBGAV1_SRC_UTILS_BLOCK_PARAMETERS_HOLDER_H_
  