org.apache.tomcat.util.buf.C2BConverter Maven / Gradle / Ivy
/*
* 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.tomcat.util.buf;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.CharsetEncoder;
import java.nio.charset.CoderResult;
import java.nio.charset.CodingErrorAction;
/**
* NIO based character encoder.
*/
public final class C2BConverter {
protected CharsetEncoder encoder = null;
protected ByteBuffer bb = null;
protected CharBuffer cb = null;
/**
* Leftover buffer used for multi-characters characters.
*/
protected CharBuffer leftovers = null;
public C2BConverter(String encoding) throws IOException {
encoder = B2CConverter.getCharset(encoding).newEncoder();
// FIXME: See if unmappable/malformed behavior configuration is needed
// in practice
encoder.onUnmappableCharacter(CodingErrorAction.REPLACE)
.onMalformedInput(CodingErrorAction.REPLACE);
char[] left = new char[4];
leftovers = CharBuffer.wrap(left);
}
/**
* Reset the encoder state.
*/
public void recycle() {
encoder.reset();
leftovers.position(0);
}
public boolean isUndeflow() {
return (leftovers.position() > 0);
}
/**
* Convert the given characters to bytes.
*
* @param cc char input
* @param bc byte output
*/
public void convert(CharChunk cc, ByteChunk bc)
throws IOException {
if ((bb == null) || (bb.array() != bc.getBuffer())) {
// Create a new byte buffer if anything changed
bb = ByteBuffer.wrap(bc.getBuffer(), bc.getEnd(),
bc.getBuffer().length - bc.getEnd());
} else {
// Initialize the byte buffer
bb.limit(bc.getBuffer().length);
bb.position(bc.getEnd());
}
if ((cb == null) || (cb.array() != cc.getBuffer())) {
// Create a new char buffer if anything changed
cb = CharBuffer.wrap(cc.getBuffer(), cc.getStart(),
cc.getLength());
} else {
// Initialize the char buffer
cb.limit(cc.getEnd());
cb.position(cc.getStart());
}
CoderResult result = null;
// Parse leftover if any are present
if (leftovers.position() > 0) {
int pos = bb.position();
// Loop until one char is encoded or there is a encoder error
do {
leftovers.put((char) cc.substract());
leftovers.flip();
result = encoder.encode(leftovers, bb, false);
leftovers.position(leftovers.limit());
leftovers.limit(leftovers.array().length);
} while (result.isUnderflow() && (bb.position() == pos));
if (result.isError() || result.isMalformed()) {
result.throwException();
}
cb.position(cc.getStart());
leftovers.position(0);
}
// Do the decoding and get the results into the byte chunk and the char
// chunk
result = encoder.encode(cb, bb, false);
if (result.isError() || result.isMalformed()) {
result.throwException();
} else if (result.isOverflow()) {
// Propagate current positions to the byte chunk and char chunk
bc.setEnd(bb.position());
cc.setOffset(cb.position());
} else if (result.isUnderflow()) {
// Propagate current positions to the byte chunk and char chunk
bc.setEnd(bb.position());
cc.setOffset(cb.position());
// Put leftovers in the leftovers char buffer
if (cc.getLength() > 0) {
leftovers.limit(leftovers.array().length);
leftovers.position(cc.getLength());
cc.substract(leftovers.array(), 0, cc.getLength());
}
}
}
}