Subversion Repositories usb_fpga_2_04

/*

 * library loader with the ability to load libraries as system resource (e.g. form the current .jar file)

 * Copyright (c) 2007-2009, ZTEX e.K.

 * http://www.ztex.de

 *

 * This library is covered by the LGPL, read LGPL.txt for details.

 */

package ch.ntb.usb;

import java.io.*;

/**

 * This class allows to load libraries in the normal way or as a system resource (e.g. form the current .jar file).

 * See below for a further description. <br>

 *

 * @author Stefan Ziegenbalg

 *

 */

public class LibLoader {

/**

 * Loads a library. This is done in three steps.<br>

 * 1. The library is tried to be load from the path list specified by the java.library.path property. <br>

 * 2. The library is tried to be load from the current directory. <br>

 * 3. The library is searched as a system resource (e.g. in the current .jar file),

 * copied to to temporary directory and loaded from there. Afterwards the temporary library is deleted.

 * The copying is necessary because libraries can't be loaded directly from .jar files.<br>

 *

 * @param libName Library name (e.g. usbJava)

 *

 * @throws UnsatisfiedLinkError

 *

 */

    public static void load( String libName ) {

// Step 1: Normal way

        try {

            System.loadLibrary( libName );

        }

        catch ( Throwable e1 ) {

// Step 2: From the current directory

            String basename = System.mapLibraryName( libName );

            try {

                System.load( System.getProperty("user.dir") + System.getProperty("file.separator") + basename );

            }

            catch ( Throwable e2 ) {

// Step 2: As system ressource

                String libFileName = System.getProperty("java.io.tmpdir") + System.getProperty("file.separator") + basename;

                try {

                    InputStream inputStream = ClassLoader.getSystemResourceAsStream( basename );

                    if ( inputStream == null ) {

                        throw new Exception();

                    }

                    File libFile = new File( libFileName );

                    FileOutputStream outputStream = new FileOutputStream( libFile );

                    byte[] buf = new byte[65536];

                    int bytesRead = -1;

                    while ( (bytesRead = inputStream.read(buf)) > 0 ) {

                        outputStream.write(buf, 0, bytesRead);

                    }

                    outputStream.close();

                    inputStream.close();

                    System.load( libFileName );

                    try {

                        libFile.delete();

                    }

                    catch (Exception e3) {

//                      System.err.println( "Warning: Cannot delete temporary library file `" + libFileName + "'" );

                    }

                }

                catch (Exception e3) {

                    throw new UnsatisfiedLinkError ("Library `"+basename+"' cannot be loaded as system resource, from current directory or from java.library.path   (java.library.path=" + System.getProperty("java.library.path")+")" );

                }

            }

        }

   }

}