/*
 * Copyright (c) 2009, 2020 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0, which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception, which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 */

package org.glassfish.grizzly.utils;

import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;
import java.util.logging.Level;
import java.util.logging.Logger;

import org.glassfish.grizzly.AbstractTransformer;
import org.glassfish.grizzly.Buffer;
import org.glassfish.grizzly.Grizzly;
import org.glassfish.grizzly.TransformationException;
import org.glassfish.grizzly.TransformationResult;
import org.glassfish.grizzly.attributes.Attribute;
import org.glassfish.grizzly.attributes.AttributeStorage;

String decoder, which decodes Buffer to String
Author:Alexey Stashok
/** * String decoder, which decodes {@link Buffer} to {@link String} * * @author Alexey Stashok */
public class StringDecoder extends AbstractTransformer<Buffer, String> { private static final Logger logger = Grizzly.logger(StringDecoder.class); protected Charset charset; protected final Attribute<Integer> lengthAttribute; protected byte[] stringTerminateBytes; @SuppressWarnings("unused") public StringDecoder() { this(null, null); } @SuppressWarnings("unused") public StringDecoder(final String stringTerminator) { this(Charset.forName("UTF-8"), stringTerminator); } public StringDecoder(final Charset charset) { this(charset, null); } public StringDecoder(final Charset charset, final String stringTerminator) { this.charset = charset != null ? charset : Charset.defaultCharset(); if (stringTerminator != null) { try { this.stringTerminateBytes = stringTerminator.getBytes(this.charset.name()); } catch (final UnsupportedEncodingException ignored) { // should never happen as we are getting charset name from Charset } } lengthAttribute = attributeBuilder.createAttribute("StringDecoder.StringSize"); } @Override public String getName() { return "StringDecoder"; } @Override protected TransformationResult<Buffer, String> transformImpl(final AttributeStorage storage, final Buffer input) throws TransformationException { if (input == null) { throw new TransformationException("Input could not be null"); } final TransformationResult<Buffer, String> result; result = stringTerminateBytes == null ? parseWithLengthPrefix(storage, input) : parseWithTerminatingSeq(storage, input); return result; } protected TransformationResult<Buffer, String> parseWithLengthPrefix(final AttributeStorage storage, final Buffer input) { Integer stringSize = lengthAttribute.get(storage); if (logger.isLoggable(Level.FINE)) { logger.log(Level.FINE, "StringDecoder decode stringSize={0} buffer={1} content={2}", new Object[] { stringSize, input, input.toStringContent() }); } if (stringSize == null) { if (input.remaining() < 4) { return TransformationResult.createIncompletedResult(input); } stringSize = input.getInt(); lengthAttribute.set(storage, stringSize); } if (input.remaining() < stringSize) { return TransformationResult.createIncompletedResult(input); } final int tmpLimit = input.limit(); input.limit(input.position() + stringSize); final String stringMessage = input.toStringContent(charset); input.position(input.limit()); input.limit(tmpLimit); return TransformationResult.createCompletedResult(stringMessage, input); } protected TransformationResult<Buffer, String> parseWithTerminatingSeq(final AttributeStorage storage, final Buffer input) { final int terminationBytesLength = stringTerminateBytes.length; int checkIndex = 0; int termIndex = -1; final Integer offsetInt = lengthAttribute.get(storage); int offset = 0; if (offsetInt != null) { offset = offsetInt; } for (int i = input.position() + offset, lim = input.limit(); i < lim; i++) { if (input.get(i) == stringTerminateBytes[checkIndex]) { checkIndex++; if (checkIndex >= terminationBytesLength) { termIndex = i - terminationBytesLength + 1; break; } } } if (termIndex >= 0) { // Terminating sequence was found final int tmpLimit = input.limit(); input.limit(termIndex); final String stringMessage = input.toStringContent(charset); input.limit(tmpLimit); input.position(termIndex + terminationBytesLength); return TransformationResult.createCompletedResult(stringMessage, input); } else { offset = input.remaining() - terminationBytesLength; if (offset < 0) { offset = 0; } lengthAttribute.set(storage, offset); return TransformationResult.createIncompletedResult(input); } } @Override public void release(final AttributeStorage storage) { lengthAttribute.remove(storage); super.release(storage); } @Override public boolean hasInputRemaining(final AttributeStorage storage, final Buffer input) { return input != null && input.hasRemaining(); } public Charset getCharset() { return charset; } public void setCharset(final Charset charset) { this.charset = charset; } }