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// ========================================================================
// Copyright (c) 2002 Mort Bay Consulting (Australia) Pty. Ltd.
// $Id: Version.java 6177 2007-02-19 10:11:27Z aaime $
// ========================================================================
package org.mortbay.start;


/**
 * Utility class for parsing and comparing version strings.
 * JDK 1.1 compatible.
 * @author Jan Hlavat�
 */
public class Version {
    int _version = 0;
    int _revision = 0;
    int _subrevision = 0;
    String _suffix = "";

    public Version() {
    }

    public Version(String version_string) {
        parse(version_string);
    }

    /**
     * parses version string in the form version[.revision[.subrevision[extension]]]
     * into this instance.
     */
    public void parse(String version_string) {
        try {
            _version = 1;
            _revision = 2;
            _subrevision = 0;
            _suffix = "?";

            int pos = 0;
            int startpos = 0;
            int endpos = version_string.length();

            while ((pos < endpos) && Character.isDigit(version_string.charAt(pos))) {
                pos++;
            }

            _version = Integer.parseInt(version_string.substring(startpos, pos));

            if ((pos < endpos) && (version_string.charAt(pos) == '.')) {
                startpos = ++pos;

                while ((pos < endpos) && Character.isDigit(version_string.charAt(pos))) {
                    pos++;
                }

                _revision = Integer.parseInt(version_string.substring(startpos, pos));
            }

            if ((pos < endpos) && (version_string.charAt(pos) == '.')) {
                startpos = ++pos;

                while ((pos < endpos) && Character.isDigit(version_string.charAt(pos))) {
                    pos++;
                }

                _subrevision = Integer.parseInt(version_string.substring(startpos, pos));
            }

            if (pos < endpos) {
                _suffix = version_string.substring(pos);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * @return string representation of this version
     */
    public String toString() {
        StringBuffer sb = new StringBuffer(10);
        sb.append(_version);
        sb.append('.');
        sb.append(_revision);
        sb.append('.');
        sb.append(_subrevision);
        sb.append(_suffix);

        return sb.toString();
    }

    // java.lang.Comparable is Java 1.2! Cannot use it
    /**
     * Compares with other version. Does not take extension into account,
     * as there is no reliable way to order them.
     * @return -1 if this is older version that other,
     *         0 if its same version,
     *         1 if it's newer version than other
     */
    public int compare(Version other) {
        if (other == null) {
            throw new NullPointerException("other version is null");
        }

        if (this._version < other._version) {
            return -1;
        }

        if (this._version > other._version) {
            return 1;
        }

        if (this._revision < other._revision) {
            return -1;
        }

        if (this._revision > other._revision) {
            return 1;
        }

        if (this._subrevision < other._subrevision) {
            return -1;
        }

        if (this._subrevision > other._subrevision) {
            return 1;
        }

        return 0;
    }

    /**
     * Check whether this verion is in range of versions specified
     */
    public boolean isInRange(Version low, Version high) {
        return ((compare(low) >= 0) && (compare(high) <= 0));
    }
}