org.sejda.sambox.util.SpecVersionUtils Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of sambox Show documentation
An Apache PDFBox fork intended to be used as PDF processor for Sejda and PDFsam related projects
There is a newer version: 3.0.21
/*
 * 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.sejda.sambox.util;

import static org.sejda.commons.util.RequireUtils.requireNotNullArg;

import java.io.IOException;
import java.util.regex.Pattern;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Utility class with pdf spec versions related methods and constants
 * 
 * @author Andrea Vacondio
 */
public class SpecVersionUtils
{
    private static final Logger LOG = LoggerFactory.getLogger(SpecVersionUtils.class);

    public static final String PDF_HEADER = "%PDF-";

    public static final String V1_0 = "1.0";
    public static final String V1_1 = "1.1";
    public static final String V1_2 = "1.2";
    public static final String V1_3 = "1.3";
    public static final String V1_4 = "1.4";
    public static final String V1_5 = "1.5";
    public static final String V1_6 = "1.6";
    public static final String V1_7 = "1.7";
    public static final String V2_0 = "2.0";

    private static final Pattern VERSION_PATTERN = Pattern.compile("^(\\d)\\.(\\d)$");

    private SpecVersionUtils()
    {
        // utility
    }

    /**
     * Parses a conforming file header string or returning the version (ex. "1.4") found. File header is defined in Chap
     * 7.5.2 of PDF 32000-1:2008
     * 
     * @param header
     * @return the parsed version (ex. "1.4")
     * @throws IOException if the string is not a valid header
     */
    public static String parseHeaderString(String header)
    {
        String versionNumberPart = header.toUpperCase().replaceAll(Pattern.quote(PDF_HEADER), "").trim();
        if(versionNumberPart.length() > 3) {
            // expecting 'a.b'
            // if the version is '1.41bla', take the first 3 chars
            versionNumberPart = versionNumberPart.substring(0, 3);
        }
        String version = sanitizeVersion(versionNumberPart);
        if (!VERSION_PATTERN.matcher(version).matches())
        {
            // it seems Acrobat doesn't choke on invalid version but it does sometime warn the user
            LOG.warn("Invalid header version {}, falling back to {}", version, V1_6);
            return V1_6;
        }
        return version;
    }

    private static String sanitizeVersion(String version)
    {
        return version.replace(',', '.');
    }

    /**
     * @param version the version to compare
     * @param atLeast min version to return true (ex. "1.5")
     * @return true if the given pdf spec version is at least as high as the given atLeast version
     */
    public static boolean isAtLeast(String version, String atLeast)
    {
        requireNotNullArg(version, "Cannot compare a null version");
        requireNotNullArg(atLeast, "Cannot compare a null version");
        return version.compareTo(atLeast) >= 0;
    }
}