/*

 * Copyright (c) 1999, 2014, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

package com.sun.media.sound;

import java.security.AccessController;

import java.security.PrivilegedAction;

import java.util.StringTokenizer;

/**

 * Audio configuration class for exposing attributes specific to the platform or system.

 *

 * @author Kara Kytle

 * @author Florian Bomers

 */

final class Platform {

    // STATIC FINAL CHARACTERISTICS

    // native library we need to load

    private static final String libNameMain     = "jsound";

    private static final String libNameALSA     = "jsoundalsa";

    private static final String libNameDSound   = "jsoundds";

    // extra libs handling: bit flags for each different library

    public static final int LIB_MAIN     = 1;

    public static final int LIB_ALSA     = 2;

    public static final int LIB_DSOUND   = 4;

    // bit field of the constants above. Willbe set in loadLibraries

    private static int loadedLibs = 0;

    // features: the main native library jsound reports which feature is

    // contained in which lib

    public static final int FEATURE_MIDIIO       = 1;

    public static final int FEATURE_PORTS        = 2;

    public static final int FEATURE_DIRECT_AUDIO = 3;

    // SYSTEM CHARACTERISTICS

    // vary according to hardware architecture

    // signed8 (use signed 8-bit values) is true for everything we support except for

    // the solaris sbpro card.

    // we'll leave it here as a variable; in the future we may need this in java.

    // wait, is that true?  i'm not sure.  i think solaris takes unsigned data?

    // $$kk: 03.11.99: i think solaris takes unsigned 8-bit or signed 16-bit data....

    private static boolean signed8;

    // intel is little-endian.  sparc is big-endian.

    private static boolean bigEndian;

    static {

        if(Printer.trace)Printer.trace(">> Platform.java: static");

        loadLibraries();

        readProperties();

    }

    /**

     * Private constructor.

     */

    private Platform() {

    }

    // METHODS FOR INTERNAL IMPLEMENTATION USE

    /**

     * Dummy method for forcing initialization.

     */

    static void initialize() {

        if(Printer.trace)Printer.trace("Platform: initialize()");

    }

    /**

     * Determine whether the system is big-endian.

     */

    static boolean isBigEndian() {

        return bigEndian;

    }

    /**

     * Determine whether the system takes signed 8-bit data.

     */

    static boolean isSigned8() {

        return signed8;

    }

    // PRIVATE METHODS

    /**

     * Load the native library or libraries.

     */

    private static void loadLibraries() {

        if(Printer.trace)Printer.trace(">>Platform.loadLibraries");

        // load the main library

        AccessController.doPrivileged((PrivilegedAction<Void>) () -> {

            System.loadLibrary(libNameMain);

            return null;

        });

        // just for the heck of it...

        loadedLibs |= LIB_MAIN;

        // now try to load extra libs. They are defined at compile time in the Makefile

        // with the define EXTRA_SOUND_JNI_LIBS

        String extraLibs = nGetExtraLibraries();

        // the string is the libraries, separated by white space

        StringTokenizer st = new StringTokenizer(extraLibs);

        while (st.hasMoreTokens()) {

            final String lib = st.nextToken();

            try {

                AccessController.doPrivileged((PrivilegedAction<Void>) () -> {

                    System.loadLibrary(lib);

                    return null;

                });

                if (lib.equals(libNameALSA)) {

                    loadedLibs |= LIB_ALSA;

                    if (Printer.debug) Printer.debug("Loaded ALSA lib successfully.");

                } else if (lib.equals(libNameDSound)) {

                    loadedLibs |= LIB_DSOUND;

                    if (Printer.debug) Printer.debug("Loaded DirectSound lib successfully.");

                } else {

                    if (Printer.err) Printer.err("Loaded unknown lib '"+lib+"' successfully.");

                }

            } catch (Throwable t) {

                if (Printer.err) Printer.err("Couldn't load library "+lib+": "+t.toString());

            }

        }

    }

    static boolean isMidiIOEnabled() {

        return isFeatureLibLoaded(FEATURE_MIDIIO);

    }

    static boolean isPortsEnabled() {

        return isFeatureLibLoaded(FEATURE_PORTS);

    }

    static boolean isDirectAudioEnabled() {

        return isFeatureLibLoaded(FEATURE_DIRECT_AUDIO);

    }

    private static boolean isFeatureLibLoaded(int feature) {

        if (Printer.debug) Printer.debug("Platform: Checking for feature "+feature+"...");

        int requiredLib = nGetLibraryForFeature(feature);

        boolean isLoaded = (requiredLib != 0) && ((loadedLibs & requiredLib) == requiredLib);

        if (Printer.debug) Printer.debug("          ...needs library "+requiredLib+". Result is loaded="+isLoaded);

        return isLoaded;

    }

    // the following native methods are implemented in Platform.c

    private native static boolean nIsBigEndian();

    private native static boolean nIsSigned8();

    private native static String nGetExtraLibraries();

    private native static int nGetLibraryForFeature(int feature);

    /**

     * Read the required system properties.

     */

    private static void readProperties() {

        // $$fb 2002-03-06: implement check for endianness in native. Facilitates porting !

        bigEndian = nIsBigEndian();

        signed8 = nIsSigned8(); // Solaris on Sparc: signed, all others unsigned

    }

}