001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 * 019 */ 020package org.apache.mina.filter.codec.statemachine; 021 022import org.apache.mina.core.buffer.IoBuffer; 023import org.apache.mina.filter.codec.ProtocolDecoderOutput; 024 025/** 026 * {@link DecodingState} which consumes all bytes until a <code>CRLF</code> 027 * has been encountered. 028 * 029 * @author <a href="http://mina.apache.org">Apache MINA Project</a> 030 */ 031public abstract class ConsumeToCrLfDecodingState implements DecodingState { 032 033 /** 034 * Carriage return character 035 */ 036 private static final byte CR = 13; 037 038 /** 039 * Line feed character 040 */ 041 private static final byte LF = 10; 042 043 private boolean lastIsCR; 044 045 private IoBuffer buffer; 046 047 /** 048 * Creates a new instance. 049 */ 050 public ConsumeToCrLfDecodingState() { 051 // Do nothing 052 } 053 054 public DecodingState decode(IoBuffer in, ProtocolDecoderOutput out) throws Exception { 055 int beginPos = in.position(); 056 int limit = in.limit(); 057 int terminatorPos = -1; 058 059 for (int i = beginPos; i < limit; i++) { 060 byte b = in.get(i); 061 if (b == CR) { 062 lastIsCR = true; 063 } else { 064 if (b == LF && lastIsCR) { 065 terminatorPos = i; 066 break; 067 } 068 lastIsCR = false; 069 } 070 } 071 072 if (terminatorPos >= 0) { 073 IoBuffer product; 074 075 int endPos = terminatorPos - 1; 076 077 if (beginPos < endPos) { 078 in.limit(endPos); 079 080 if (buffer == null) { 081 product = in.slice(); 082 } else { 083 buffer.put(in); 084 product = buffer.flip(); 085 buffer = null; 086 } 087 088 in.limit(limit); 089 } else { 090 // When input contained only CR or LF rather than actual data... 091 if (buffer == null) { 092 product = IoBuffer.allocate(0); 093 } else { 094 product = buffer.flip(); 095 buffer = null; 096 } 097 } 098 in.position(terminatorPos + 1); 099 return finishDecode(product, out); 100 } 101 102 in.position(beginPos); 103 104 if (buffer == null) { 105 buffer = IoBuffer.allocate(in.remaining()); 106 buffer.setAutoExpand(true); 107 } 108 109 buffer.put(in); 110 111 if (lastIsCR) { 112 buffer.position(buffer.position() - 1); 113 } 114 115 return this; 116 } 117 118 /** 119 * {@inheritDoc} 120 */ 121 public DecodingState finishDecode(ProtocolDecoderOutput out) throws Exception { 122 IoBuffer product; 123 // When input contained only CR or LF rather than actual data... 124 if (buffer == null) { 125 product = IoBuffer.allocate(0); 126 } else { 127 product = buffer.flip(); 128 buffer = null; 129 } 130 return finishDecode(product, out); 131 } 132 133 /** 134 * Invoked when this state has reached a <code>CRLF</code>. 135 * 136 * @param product the read bytes including the <code>CRLF</code>. 137 * @param out the current {@link ProtocolDecoderOutput} used to write 138 * decoded messages. 139 * @return the next state if a state transition was triggered (use 140 * <code>this</code> for loop transitions) or <code>null</code> if 141 * the state machine has reached its end. 142 * @throws Exception if the read data violated protocol specification. 143 */ 144 protected abstract DecodingState finishDecode(IoBuffer product, ProtocolDecoderOutput out) throws Exception; 145}