// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.  All rights reserved.
// https://developers.google.com/protocol-buffers/
//
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// modification, are permitted provided that the following conditions are
// met:
//
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// in the documentation and/or other materials provided with the
// distribution.
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package com.google.protobuf;

import java.nio.ByteBuffer;

/**
 * An object responsible for allocation of buffers. This is an extension point to enable buffer
 * pooling within an application.
 */
@ExperimentalApi
public abstract class BufferAllocator {
  private static final BufferAllocator UNPOOLED =
      new BufferAllocator() {
        @Override
        public AllocatedBuffer allocateHeapBuffer(int capacity) {
          return AllocatedBuffer.wrap(new byte[capacity]);
        }

        @Override
        public AllocatedBuffer allocateDirectBuffer(int capacity) {
          return AllocatedBuffer.wrap(ByteBuffer.allocateDirect(capacity));
        }
      };

  /**
   * Returns an unpooled buffer allocator, which will create a new buffer for each request.
   */
  public static BufferAllocator unpooled() {
    return UNPOOLED;
  }

  /**
   * Allocates a buffer with the given capacity that is backed by an array on the heap.
   */
  public abstract AllocatedBuffer allocateHeapBuffer(int capacity);

  /**
   * Allocates a direct (i.e. non-heap) buffer with the given capacity.
   */
  public abstract AllocatedBuffer allocateDirectBuffer(int capacity);
}