content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to you 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 org.apache.calcite.avatica.util;
  
  import java.io.IOException;
  import java.io.OutputStream;
  
  /**
   * A utility class for reading and writing bytes to byte buffers without synchronization. A
   * reduced variant taken from Apache Accumulo. This class is <b>not</b> thread-safe by design.
   * It is up to the caller to guarantee mutual exclusion as necessary.
   */
  public class UnsynchronizedBuffer extends OutputStream {
    // Anything larger than 64K, reap the backing buffer
    private static final int LARGE_BUFFER_SIZE = 1024 * 64;
  
    final int initialCapacity;
    int offset = 0;
    byte[] data;
  
    /**
     * Creates a new writer.
     */
    public UnsynchronizedBuffer() {
      this(4096);
    }
  
    /**
     * Creates a new writer.
     *
     * @param initialCapacity initial byte capacity
     */
    public UnsynchronizedBuffer(int initialCapacity) {
      this.initialCapacity = initialCapacity;
      data = new byte[initialCapacity];
    }
  
    private void reserve(int l) {
      if (offset + l > data.length) {
        int newSize = UnsynchronizedBuffer.nextArraySize(offset + l);
  
        byte[] newData = new byte[newSize];
        System.arraycopy(data, 0, newData, 0, offset);
        data = newData;
      }
  
    }
  
    /**
     * Adds bytes to this writer's buffer.
     *
     * @param bytes byte array
     * @param off offset into array to start copying bytes
     * @param length number of bytes to add
     * @throws IndexOutOfBoundsException if off or length are invalid
     */
    public void write(byte[] bytes, int off, int length) {
      reserve(length);
      System.arraycopy(bytes, off, data, offset, length);
      offset += length;
    }
  
    @Override public void write(int b) throws IOException {
      reserve(1);
      data[offset] = (byte) b;
      offset++;
    }
  
    /**
     * Gets (a copy of) the contents of this writer's buffer.
     *
     * @return byte buffer contents
     */
    public byte[] toArray() {
      byte[] ret = new byte[offset];
      System.arraycopy(data, 0, ret, 0, offset);
      return ret;
    }
  
    /**
     * Resets the internal pointer into the buffer.
     */
    public void reset() {
      offset = 0;
      if (data.length >= LARGE_BUFFER_SIZE) {
        data = new byte[this.initialCapacity];
      }
    }
  
    /**
     * @return The current offset into the backing array.
     */
    public int getOffset() {
      return offset;
    }
  
    /**
     * @return The current length of the backing array.
     */
    public long getSize() {
      return data.length;
    }
  
    /**
     * Determines what next array size should be by rounding up to next power of two.
     *
     * @param i current array size
     * @return next array size
     * @throws IllegalArgumentException if i is negative
     */
    public static int nextArraySize(int i) {
      if (i < 0) {
        throw new IllegalArgumentException();
      }
  
      if (i > (1 << 30)) {
        return Integer.MAX_VALUE; // this is the next power of 2 minus one... a special case
      }
  
      if (i == 0) {
        return 1;
      }
  
      // round up to next power of two
      int ret = i;
      ret--;
      ret |= ret >> 1;
      ret |= ret >> 2;
      ret |= ret >> 4;
      ret |= ret >> 8;
      ret |= ret >> 16;
      ret++;
  
      return ret;
    }
  }
  
  // End UnsynchronizedBuffer.java
  