content: /*
   * Copyright (C) 2016 The Android Open Source Project
   *
   * 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.
   */
  package com.google.android.exoplayer2.upstream;
  
  import androidx.annotation.Nullable;
  
  /** A source of allocations. */
  public interface Allocator {
  
    /** A node in a chain of {@link Allocation Allocations}. */
    interface AllocationNode {
  
      /** Returns the {@link Allocation} associated to this chain node. */
      Allocation getAllocation();
  
      /** Returns the next chain node, or {@code null} if this is the last node in the chain. */
      @Nullable
      AllocationNode next();
    }
  
    /**
     * Obtain an {@link Allocation}.
     *
     * <p>When the caller has finished with the {@link Allocation}, it should be returned by calling
     * {@link #release(Allocation)}.
     *
     * @return The {@link Allocation}.
     */
    Allocation allocate();
  
    /**
     * Releases an {@link Allocation} back to the allocator.
     *
     * @param allocation The {@link Allocation} being released.
     */
    void release(Allocation allocation);
  
    /**
     * Releases all {@link Allocation Allocations} in the chain starting at the given {@link
     * AllocationNode}.
     *
     * <p>Implementations must not make memory allocations.
     */
    void release(AllocationNode allocationNode);
  
    /**
     * Hints to the allocator that it should make a best effort to release any excess {@link
     * Allocation Allocations}.
     */
    void trim();
  
    /** Returns the total number of bytes currently allocated. */
    int getTotalBytesAllocated();
  
    /** Returns the length of each individual {@link Allocation}. */
    int getIndividualAllocationLength();
  }
  