001/** 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.activemq.transport.tcp; 018 019import java.io.FilterInputStream; 020import java.io.IOException; 021import java.io.InputStream; 022 023/** 024 * An optimized buffered input stream for Tcp 025 * 026 * 027 */ 028public class TcpBufferedInputStream extends FilterInputStream { 029 private static final int DEFAULT_BUFFER_SIZE = 8192; 030 protected byte internalBuffer[]; 031 protected int count; 032 protected int position; 033 034 public TcpBufferedInputStream(InputStream in) { 035 this(in, DEFAULT_BUFFER_SIZE); 036 } 037 038 public TcpBufferedInputStream(InputStream in, int size) { 039 super(in); 040 if (size <= 0) { 041 throw new IllegalArgumentException("Buffer size <= 0"); 042 } 043 internalBuffer = new byte[size]; 044 } 045 046 protected void fill() throws IOException { 047 byte[] buffer = internalBuffer; 048 count = 0; 049 position = 0; 050 int n = in.read(buffer, position, buffer.length - position); 051 if (n > 0) { 052 count = n + position; 053 } 054 } 055 056 @Override 057 public int read() throws IOException { 058 if (position >= count) { 059 fill(); 060 if (position >= count) { 061 return -1; 062 } 063 } 064 return internalBuffer[position++] & 0xff; 065 } 066 067 private int readStream(byte[] b, int off, int len) throws IOException { 068 int avail = count - position; 069 if (avail <= 0) { 070 if (len >= internalBuffer.length) { 071 return in.read(b, off, len); 072 } 073 fill(); 074 avail = count - position; 075 if (avail <= 0) { 076 return -1; 077 } 078 } 079 int cnt = (avail < len) ? avail : len; 080 System.arraycopy(internalBuffer, position, b, off, cnt); 081 position += cnt; 082 return cnt; 083 } 084 085 @Override 086 public int read(byte b[], int off, int len) throws IOException { 087 if ((off | len | (off + len) | (b.length - (off + len))) < 0) { 088 throw new IndexOutOfBoundsException(); 089 } else if (len == 0) { 090 return 0; 091 } 092 int n = 0; 093 for (;;) { 094 int nread = readStream(b, off + n, len - n); 095 if (nread <= 0) { 096 return (n == 0) ? nread : n; 097 } 098 n += nread; 099 if (n >= len) { 100 return n; 101 } 102 // if not closed but no bytes available, return 103 InputStream input = in; 104 if (input != null && input.available() <= 0) { 105 return n; 106 } 107 } 108 } 109 110 @Override 111 public long skip(long n) throws IOException { 112 if (n <= 0) { 113 return 0; 114 } 115 long avail = count - position; 116 if (avail <= 0) { 117 return in.skip(n); 118 } 119 long skipped = (avail < n) ? avail : n; 120 position += skipped; 121 return skipped; 122 } 123 124 @Override 125 public int available() throws IOException { 126 return in.available() + (count - position); 127 } 128 129 @Override 130 public boolean markSupported() { 131 return false; 132 } 133 134 @Override 135 public void close() throws IOException { 136 if (in != null) { 137 in.close(); 138 } 139 } 140 141 /** 142 * @param array 143 * @throws IOException 144 */ 145 public void unread(byte[] array) throws IOException { 146 int avail = internalBuffer.length - position; 147 if (array.length > avail) { 148 throw new IOException("Buffer is full, can't unread"); 149 } 150 151 System.arraycopy(array, position, internalBuffer, 0, array.length); 152 count += array.length; 153 } 154}