src/utils/dynamic_buffer.h

/*
 * Copyright 2020 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_DYNAMIC_BUFFER_H_
#define LIBGAV1_SRC_UTILS_DYNAMIC_BUFFER_H_

#include <cstddef>
#include <memory>
#include <new>

#include "src/utils/memory.h"

namespace libgav1 {

template <typename T>
class DynamicBuffer {
 public:
  T* get() { return buffer_.get(); }
  const T* get() const { return buffer_.get(); }

  // Resizes the buffer so that it can hold at least |size| elements. Existing
  // contents will be destroyed when resizing to a larger size.
  //
  // Returns true on success. If Resize() returns false, then subsequent calls
  // to get() will return nullptr.
  bool Resize(size_t size) {
    if (size <= size_) return true;
    buffer_.reset(new (std::nothrow) T[size]);
    if (buffer_ == nullptr) {
      size_ = 0;
      return false;
    }
    size_ = size;
    return true;
  }

  size_t size() const { return size_; }

 private:
  std::unique_ptr<T[]> buffer_;
  size_t size_ = 0;
};

template <typename T, int alignment>
class AlignedDynamicBuffer {
 public:
  T* get() { return buffer_.get(); }

  // Resizes the buffer so that it can hold at least |size| elements. Existing
  // contents will be destroyed when resizing to a larger size.
  //
  // Returns true on success. If Resize() returns false, then subsequent calls
  // to get() will return nullptr.
  bool Resize(size_t size) {
    if (size <= size_) return true;
    buffer_ = MakeAlignedUniquePtr<T>(alignment, size);
    if (buffer_ == nullptr) {
      size_ = 0;
      return false;
    }
    size_ = size;
    return true;
  }

 private:
  AlignedUniquePtr<T> buffer_;
  size_t size_ = 0;
};

}  // namespace libgav1

#endif  // LIBGAV1_SRC_UTILS_DYNAMIC_BUFFER_H_