org.apache.xmlgraphics.xmp.XMPPacketParser 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.
 */

/* $Id: XMPPacketParser.java 1681108 2015-05-22 13:26:12Z ssteiner $ */

package org.apache.xmlgraphics.xmp;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;

import javax.xml.transform.TransformerException;
import javax.xml.transform.stream.StreamSource;

import org.apache.commons.io.IOUtils;
import org.apache.commons.io.output.ByteArrayOutputStream;

/**
 * This class is a parser for XMP packets. By default, it tries to locate the first XMP packet
 * it finds and parses it.
 * 
 * Important: Before you use this class to look for an XMP packet in some random file, please read
 * the chapter on "Scanning Files for XMP Packets" in the XMP specification!
 */
public final class XMPPacketParser {

    private XMPPacketParser() {
    }

    private static final byte[] PACKET_HEADER;
    private static final byte[] PACKET_HEADER_END;
    private static final byte[] PACKET_TRAILER;

    static {
        try {
            PACKET_HEADER = "".getBytes("US-ASCII");
            PACKET_TRAILER = "= 0) {
            if (b == match[found]) {
                found++;
                if (found == len) {
                    return true;
                }
            } else {
                if (out != null) {
                    if (found > 0) {
                        out.write(match, 0, found);
                    }
                    out.write(b);
                }
                found = 0;
            }
        }
        return false;
    }

}