B2CConverter.java
/*
* 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.io.UnsupportedEncodingException;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CoderResult;
import java.nio.charset.CodingErrorAction;
import java.util.Locale;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
import org.apache.tomcat.util.ExceptionUtils;
import org.apache.tomcat.util.res.StringManager;
/**
* NIO based character decoder.
*/
public class B2CConverter {
private static final Log log = LogFactory.getLog(B2CConverter.class);
private static final StringManager sm = StringManager.getManager(B2CConverter.class);
private static final CharsetCache charsetCache = new CharsetCache();
// Protected so unit tests can use it
protected static final int LEFTOVER_SIZE = 9;
/**
* Obtain the Charset for the given encoding
*
* @param enc The name of the encoding for the required charset
*
* @return The Charset corresponding to the requested encoding
*
* @throws UnsupportedEncodingException If the requested Charset is not available
*/
public static Charset getCharset(String enc) throws UnsupportedEncodingException {
// Encoding names should all be ASCII
String lowerCaseEnc = enc.toLowerCase(Locale.ENGLISH);
Charset charset = charsetCache.getCharset(lowerCaseEnc);
if (charset == null) {
// Pre-population of the cache means this must be invalid
throw new UnsupportedEncodingException(sm.getString("b2cConverter.unknownEncoding", lowerCaseEnc));
}
return charset;
}
private final CharsetDecoder decoder;
private ByteBuffer bb = null;
private CharBuffer cb = null;
/**
* Leftover buffer used for incomplete characters.
*/
private final ByteBuffer leftovers;
public B2CConverter(Charset charset) {
this(charset, false);
}
public B2CConverter(Charset charset, boolean replaceOnError) {
byte[] left = new byte[LEFTOVER_SIZE];
leftovers = ByteBuffer.wrap(left);
CodingErrorAction action;
if (replaceOnError) {
action = CodingErrorAction.REPLACE;
} else {
action = CodingErrorAction.REPORT;
}
decoder = charset.newDecoder();
decoder.onMalformedInput(action);
decoder.onUnmappableCharacter(action);
}
/**
* Reset the decoder state.
*/
public void recycle() {
try {
decoder.reset();
} catch (Throwable t) {
ExceptionUtils.handleThrowable(t);
log.warn(sm.getString("b2cConverter.decoderResetFail", decoder.charset()), t);
}
leftovers.position(0);
}
/**
* Convert the given bytes to characters.
*
* @param bc byte input
* @param cc char output
* @param endOfInput Is this all of the available data
*
* @throws IOException If the conversion can not be completed
*/
public void convert(ByteChunk bc, CharChunk cc, boolean endOfInput) throws IOException {
if ((bb == null) || (bb.array() != bc.getBuffer())) {
// Create a new byte buffer if anything changed
bb = ByteBuffer.wrap(bc.getBuffer(), bc.getStart(), bc.getLength());
} else {
// Initialize the byte buffer
bb.limit(bc.getEnd());
bb.position(bc.getStart());
}
if ((cb == null) || (cb.array() != cc.getBuffer())) {
// Create a new char buffer if anything changed
cb = CharBuffer.wrap(cc.getBuffer(), cc.getEnd(), cc.getBuffer().length - cc.getEnd());
} else {
// Initialize the char buffer
cb.limit(cc.getBuffer().length);
cb.position(cc.getEnd());
}
CoderResult result = null;
// Parse leftover if any are present
if (leftovers.position() > 0) {
int pos = cb.position();
// Loop until one char is decoded or there is a decoder error
do {
leftovers.put(bc.subtractB());
leftovers.flip();
result = decoder.decode(leftovers, cb, endOfInput);
leftovers.position(leftovers.limit());
leftovers.limit(leftovers.array().length);
} while (result.isUnderflow() && (cb.position() == pos));
if (result.isError() || result.isMalformed()) {
result.throwException();
}
bb.position(bc.getStart());
leftovers.position(0);
}
// Do the decoding and get the results into the byte chunk and the char
// chunk
result = decoder.decode(bb, cb, endOfInput);
if (result.isError() || result.isMalformed()) {
result.throwException();
} else if (result.isOverflow()) {
// Propagate current positions to the byte chunk and char chunk, if
// this continues the char buffer will get resized
bc.setOffset(bb.position());
cc.setEnd(cb.position());
} else if (result.isUnderflow()) {
// Propagate current positions to the byte chunk and char chunk
bc.setOffset(bb.position());
cc.setEnd(cb.position());
// Put leftovers in the leftovers byte buffer
if (bc.getLength() > 0) {
leftovers.limit(leftovers.array().length);
leftovers.position(bc.getLength());
bc.subtract(leftovers.array(), 0, bc.getLength());
}
}
}
/**
* Convert the given bytes to characters.
*
* @param bc byte input
* @param cc char output
* @param ic byte input channel
* @param endOfInput Is this all of the available data
*
* @throws IOException If the conversion can not be completed
*/
public void convert(ByteBuffer bc, CharBuffer cc, ByteChunk.ByteInputChannel ic, boolean endOfInput)
throws IOException {
if ((bb == null) || (bb.array() != bc.array())) {
// Create a new byte buffer if anything changed
bb = ByteBuffer.wrap(bc.array(), bc.arrayOffset() + bc.position(), bc.remaining());
} else {
// Initialize the byte buffer
bb.limit(bc.limit());
bb.position(bc.position());
}
if ((cb == null) || (cb.array() != cc.array())) {
// Create a new char buffer if anything changed
cb = CharBuffer.wrap(cc.array(), cc.limit(), cc.capacity() - cc.limit());
} else {
// Initialize the char buffer
cb.limit(cc.capacity());
cb.position(cc.limit());
}
CoderResult result = null;
// Parse leftover if any are present
if (leftovers.position() > 0) {
int pos = cb.position();
// Loop until one char is decoded or there is a decoder error
do {
byte chr;
if (bc.remaining() == 0) {
int n = ic.realReadBytes();
chr = n < 0 ? -1 : bc.get();
} else {
chr = bc.get();
}
leftovers.put(chr);
leftovers.flip();
result = decoder.decode(leftovers, cb, endOfInput);
leftovers.position(leftovers.limit());
leftovers.limit(leftovers.array().length);
} while (result.isUnderflow() && (cb.position() == pos));
if (result.isError() || result.isMalformed()) {
result.throwException();
}
bb.position(bc.position());
leftovers.position(0);
}
// Do the decoding and get the results into the byte chunk and the char
// chunk
result = decoder.decode(bb, cb, endOfInput);
if (result.isError() || result.isMalformed()) {
result.throwException();
} else if (result.isOverflow()) {
// Propagate current positions to the byte chunk and char chunk, if
// this continues the char buffer will get resized
bc.position(bb.position());
cc.limit(cb.position());
} else if (result.isUnderflow()) {
// Propagate current positions to the byte chunk and char chunk
bc.position(bb.position());
cc.limit(cb.position());
// Put leftovers in the leftovers byte buffer
if (bc.remaining() > 0) {
leftovers.limit(leftovers.array().length);
leftovers.position(bc.remaining());
bc.get(leftovers.array(), 0, bc.remaining());
}
}
}
public Charset getCharset() {
return decoder.charset();
}
}