ceph/src/jaegertracing/thrift/lib/java/src/org/apache/thrift/transport/AutoExpandingBuffer.java

   1 /*
   2  * Licensed to the Apache Software Foundation (ASF) under one
   3  * or more contributor license agreements. See the NOTICE file
   4  * distributed with this work for additional information
   5  * regarding copyright ownership. The ASF licenses this file
   6  * to you under the Apache License, Version 2.0 (the
   7  * "License"); you may not use this file except in compliance
   8  * with the License. You may obtain a copy of the License at
   9  *
  10  *   http://www.apache.org/licenses/LICENSE-2.0
  11  *
  12  * Unless required by applicable law or agreed to in writing,
  13  * software distributed under the License is distributed on an
  14  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  15  * KIND, either express or implied. See the License for the
  16  * specific language governing permissions and limitations
  17  * under the License.
  18  */
  19 package org.apache.thrift.transport;
  20
  21 import java.util.Arrays;
  22
  23 /**
  24  * Helper class that wraps a byte[] so that it can expand and be reused. Users
  25  * should call resizeIfNecessary to make sure the buffer has suitable capacity,
  26  * and then use the array as needed. Note that the internal array will grow at a
  27  * rate slightly faster than the requested capacity with the (untested)
  28  * objective of avoiding expensive buffer allocations and copies.
  29  */
  30 class AutoExpandingBuffer {
  31   private byte[] array;
  32
  33   public AutoExpandingBuffer(int initialCapacity) {
  34     this.array = new byte[initialCapacity];
  35   }
  36
  37   public void resizeIfNecessary(int size) {
  38     final int currentCapacity = this.array.length;
  39     if (currentCapacity < size) {
  40       // Increase by a factor of 1.5x
  41       int growCapacity = currentCapacity + (currentCapacity >> 1);
  42       int newCapacity = Math.max(growCapacity, size);
  43       this.array = Arrays.copyOf(array, newCapacity);
  44     }
  45   }
  46
  47   public byte[] array() {
  48     return this.array;
  49   }
  50 }