| /** |
| * 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.hadoop.io; |
| |
| import java.io.EOFException; |
| import java.io.IOException; |
| import java.io.OutputStream; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| |
| /** |
| * A byte array backed output stream with a limit. The limit should be smaller |
| * than the buffer capacity. The object can be reused through <code>reset</code> |
| * API and choose different limits in each round. |
| */ |
| @InterfaceAudience.LimitedPrivate({"HDFS", "MapReduce"}) |
| @InterfaceStability.Unstable |
| public class BoundedByteArrayOutputStream extends OutputStream { |
| private byte[] buffer; |
| private int startOffset; |
| private int limit; |
| private int currentPointer; |
| |
| /** |
| * Create a BoundedByteArrayOutputStream with the specified |
| * capacity |
| * @param capacity The capacity of the underlying byte array |
| */ |
| public BoundedByteArrayOutputStream(int capacity) { |
| this(capacity, capacity); |
| } |
| |
| /** |
| * Create a BoundedByteArrayOutputStream with the specified |
| * capacity and limit. |
| * @param capacity The capacity of the underlying byte array |
| * @param limit The maximum limit upto which data can be written |
| */ |
| public BoundedByteArrayOutputStream(int capacity, int limit) { |
| this(new byte[capacity], 0, limit); |
| } |
| |
| protected BoundedByteArrayOutputStream(byte[] buf, int offset, int limit) { |
| resetBuffer(buf, offset, limit); |
| } |
| |
| protected void resetBuffer(byte[] buf, int offset, int limit) { |
| int capacity = buf.length - offset; |
| if ((capacity < limit) || (capacity | limit) < 0) { |
| throw new IllegalArgumentException("Invalid capacity/limit"); |
| } |
| this.buffer = buf; |
| this.startOffset = offset; |
| this.currentPointer = offset; |
| this.limit = offset + limit; |
| } |
| |
| @Override |
| public void write(int b) throws IOException { |
| if (currentPointer >= limit) { |
| throw new EOFException("Reaching the limit of the buffer."); |
| } |
| buffer[currentPointer++] = (byte) b; |
| } |
| |
| @Override |
| public void write(byte b[], int off, int len) throws IOException { |
| if ((off < 0) || (off > b.length) || (len < 0) || ((off + len) > b.length) |
| || ((off + len) < 0)) { |
| throw new IndexOutOfBoundsException(); |
| } else if (len == 0) { |
| return; |
| } |
| |
| if (currentPointer + len > limit) { |
| throw new EOFException("Reach the limit of the buffer"); |
| } |
| |
| System.arraycopy(b, off, buffer, currentPointer, len); |
| currentPointer += len; |
| } |
| |
| /** |
| * Reset the limit |
| * @param newlim New Limit |
| */ |
| public void reset(int newlim) { |
| if (newlim > (buffer.length - startOffset)) { |
| throw new IndexOutOfBoundsException("Limit exceeds buffer size"); |
| } |
| this.limit = newlim; |
| this.currentPointer = startOffset; |
| } |
| |
| /** Reset the buffer */ |
| public void reset() { |
| this.limit = buffer.length - startOffset; |
| this.currentPointer = startOffset; |
| } |
| |
| /** Return the current limit */ |
| public int getLimit() { |
| return limit; |
| } |
| |
| /** Returns the underlying buffer. |
| * Data is only valid to {@link #size()}. |
| */ |
| public byte[] getBuffer() { |
| return buffer; |
| } |
| |
| /** Returns the length of the valid data |
| * currently in the buffer. |
| */ |
| public int size() { |
| return currentPointer - startOffset; |
| } |
| |
| public int available() { |
| return limit - currentPointer; |
| } |
| } |