package org.eclipse.swt.internal;

/*
 * Copyright (c) 2000, 2002 IBM Corp.  All rights reserved.
 * This file is made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 */

public class Library {

	/* SWT Version - Mmmm (M=major, mmm=minor) */
	
	/**
	 * SWT Major version number (must be >= 0)
	 */
	static int MAJOR_VERSION = 2;
	
	/**
	 * SWT Minor version number (must be in the range 0..999)
	 */
	static int MINOR_VERSION = 47;
	
	/**
	 * SWT revision number (must be >= 0)
	 */
	static int REVISION = 0;

/**
 * Returns the SWT version as an integer in the standard format
 * <em>Mmmm</em> where <em>M</em> is the major version number
 * and <em>mmm</em> is the minor version number.
 *
 * @return the version of the currently running SWT
 */
public static int getVersion () {
	return MAJOR_VERSION * 1000 + MINOR_VERSION;
}

/**
 * Returns the platform name.
 *
 * @return the platform name of the currently running SWT
 */
static String getPlatform () {
	String [] names = new String [] {"motif", "gtk", "win32", "photon", "carbon"};
	for (int i = 0; i < names.length; i++) {
		try {
			Class.forName("org.eclipse.swt.internal."+names[i]+".OS");
			return names[i];
		} catch (ClassNotFoundException e) {
		}
	}
	return "unknown";
}

/**
 * Returns the SWT revision number as an integer. Revision changes
 * occur as a result of non-API breaking bug fixes.
 *
 * @return the revision number of the currently running SWT
 */
public static int getRevision () {
	return REVISION;
}
	
/**
 * Loads the shared library that matches the version of the
 * Java code which is currently running.  SWT shared libraries
 * follow an encoding scheme where the major, minor and revision
 * numbers are embedded in the library name and this along with
 * <code>name</code> is used to load the library.  If this fails,
 * <code>name</code> is used in another attempt to load the library,
 * this time ignoring the SWT version encoding scheme.
 *
 * @param name the name of the library to load
 */
public static void loadLibrary (String name) {
	/*
     * Include platform name to support different windowing systems
     * on same operating system.
	 */
	String platform = getPlatform ();
	
	/*
	 * Get version qualifier.
	 */
	String version = System.getProperty ("swt.version");
	if (version == null) {
		version = "" + MAJOR_VERSION;
		/* Force 3 digits in minor version number */
		if (MINOR_VERSION < 10) {
			version += "00";
		} else {
			if (MINOR_VERSION < 100) version += "0";
		}
		version += MINOR_VERSION;		
		/* No "r" until first revision */
		if (REVISION > 0) version += "r" + REVISION;
	}

	try {
		String newName = name + "-" + platform + "-" + version;		
		System.loadLibrary (newName);
		return;
	} catch (UnsatisfiedLinkError e1) {		
		try {
			String newName = name + "-" + platform;
			System.loadLibrary (newName);
			return;
		} catch (UnsatisfiedLinkError e2) {
			throw e1;
		}
	}
}

}