org.apache.mina.filter.codec.statemachine.CrLfDecodingState Maven / Gradle / Ivy
/**
* Copyright 2007-2015, Kaazing Corporation. All rights reserved.
*
* Licensed 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.mina.filter.codec.statemachine;
import org.apache.mina.core.buffer.IoBuffer;
import org.apache.mina.filter.codec.ProtocolDecoderException;
import org.apache.mina.filter.codec.ProtocolDecoderOutput;
/**
* {@link DecodingState} which decodes a single CRLF
.
* If it is found, the bytes are consumed and true
* is provided as the product. Otherwise, read bytes are pushed back
* to the stream, and false
is provided as the
* product.
* Note that if we find a CR but do not find a following LF, we raise
* an error.
*
* @author Apache MINA Project
*/
public abstract class CrLfDecodingState implements DecodingState {
/**
* Carriage return character
*/
private static final byte CR = 13;
/**
* Line feed character
*/
private static final byte LF = 10;
private boolean hasCR;
/**
* {@inheritDoc}
*/
public DecodingState decode(IoBuffer in, ProtocolDecoderOutput out)
throws Exception {
boolean found = false;
boolean finished = false;
while (in.hasRemaining()) {
byte b = in.get();
if (!hasCR) {
if (b == CR) {
hasCR = true;
} else {
if (b == LF) {
found = true;
} else {
in.position(in.position() - 1);
found = false;
}
finished = true;
break;
}
} else {
if (b == LF) {
found = true;
finished = true;
break;
}
throw new ProtocolDecoderException(
"Expected LF after CR but was: " + (b & 0xff));
}
}
if (finished) {
hasCR = false;
return finishDecode(found, out);
}
return this;
}
/**
* {@inheritDoc}
*/
public DecodingState finishDecode(ProtocolDecoderOutput out)
throws Exception {
return finishDecode(false, out);
}
/**
* Invoked when this state has found a CRLF
.
*
* @param foundCRLF true
if CRLF
was found.
* @param out the current {@link ProtocolDecoderOutput} used to write
* decoded messages.
* @return the next state if a state transition was triggered (use
* this
for loop transitions) or null
if
* the state machine has reached its end.
* @throws Exception if the read data violated protocol specification.
*/
protected abstract DecodingState finishDecode(boolean foundCRLF,
ProtocolDecoderOutput out) throws Exception;
}