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 public int read() throws IOException { 057 if (position >= count) { 058 fill(); 059 if (position >= count) { 060 return -1; 061 } 062 } 063 return internalBuffer[position++] & 0xff; 064 } 065 066 private int readStream(byte[] b, int off, int len) throws IOException { 067 int avail = count - position; 068 if (avail <= 0) { 069 if (len >= internalBuffer.length) { 070 return in.read(b, off, len); 071 } 072 fill(); 073 avail = count - position; 074 if (avail <= 0) { 075 return -1; 076 } 077 } 078 int cnt = (avail < len) ? avail : len; 079 System.arraycopy(internalBuffer, position, b, off, cnt); 080 position += cnt; 081 return cnt; 082 } 083 084 public int read(byte b[], int off, int len) throws IOException { 085 if ((off | len | (off + len) | (b.length - (off + len))) < 0) { 086 throw new IndexOutOfBoundsException(); 087 } else if (len == 0) { 088 return 0; 089 } 090 int n = 0; 091 for (;;) { 092 int nread = readStream(b, off + n, len - n); 093 if (nread <= 0) { 094 return (n == 0) ? nread : n; 095 } 096 n += nread; 097 if (n >= len) { 098 return n; 099 } 100 // if not closed but no bytes available, return 101 InputStream input = in; 102 if (input != null && input.available() <= 0) { 103 return n; 104 } 105 } 106 } 107 108 public long skip(long n) throws IOException { 109 if (n <= 0) { 110 return 0; 111 } 112 long avail = count - position; 113 if (avail <= 0) { 114 return in.skip(n); 115 } 116 long skipped = (avail < n) ? avail : n; 117 position += skipped; 118 return skipped; 119 } 120 121 public int available() throws IOException { 122 return in.available() + (count - position); 123 } 124 125 public boolean markSupported() { 126 return false; 127 } 128 129 public void close() throws IOException { 130 if (in != null) { 131 in.close(); 132 } 133 } 134}