Celestin Apprentice 2/Apprentice-Release2.iso/Source Code/Libraries/VideoToolbox 94.11.17/VideoToolboxSources/SndPlay1.c

C/C++ Source or Header | 1994-11-17 | 5.0 KB | 154 lines | [TEXT/KAHL]

/*
SndPlay1.c

SndPlay1(snd) plays a sound, asynchronously, i.e. it returns immediately, while the
sound is still playing. The argument is a handle to a snd resource. If a sound is
still playing from a previous call to SndPlay1, it is allowed to finish before
closing and reopening the channel and beginning the new sound.
SndPlay1(NULL) waits for the sound to end and then closes the channel.
SndStop1() closes the channel immediately.
SndDone1() returns true once the last sound initiated by SndPlay1() has
finished.

GENERAL NOTE:
The Apple Sound Manager has the annoying characteristic of insisting on loading
any synth that's mentioned in a snd resource, even if that synth is already loaded,
which causes an error. This makes it necessary to dispose of and recreate the
snd channel before each new sound, which these routines do. Apple advises against
this approach because it leaves the channel open a lot of the time,
which blocks SysBeep.

To avoid this, make sure to call SndPlay1(NULL) or SndStop1() to close the channel after
you start a sound going.

The easiest way to get a sound to play is to call GetNamedResource().
    Handle snd;
    snd=GetNamedResource('snd ',"\pSimple Beep");
However, it's also easy to create your own snd in memory, as a series of commands,
following the instructions in Inside Mac VI.

HISTORY:
3/30/92    dgp wrote it.
4/1/92    dgp    renamed it and commented out the printf's.
7/9/93    dgp Test MATLAB in if() instead of #if.
5/28/94 dgp Made compatible with Apple's Universal Headers. Thanks to Bob Dougherty
([e-mail]) for reporting the incompatibility.
9/5/94 dgp removed assumption in printf's that int==short.
9/10/94 dgp cosmetic
10/5/94 dgp simplified SndCallBack1 until it stopped crashing when I run native on ppc.
10/27/94 dgp It is very annoying for the machine to crash anytime you try to quit your application
by escaping via MacsBugs escape to shell. The problem is that CodeWarrior 4.5 doesn't attach
the atexit() tasks to _EscapeToShell. So I do it here.
*/
#include "VideoToolbox.h"
#include <Sound.h>
static pascal void SndCallBack1(SndChannelPtr channel,SndCommand command);
static SndChannelPtr channel=NULL;
static SndCommand callBack;
#if !defined(NewSndCallBackProc)
    #define NewSndCallBackProc (SndCallBackUPP)
    typedef ProcPtr SndCallBackUPP;
#endif
static void PatchExitToShell(void);

OSErr SndPlay1(Handle snd)
{
    int error=0;

    static firstTime=1;
    static SndCallBackUPP sndCallBackProc;

    if(firstTime){
        sndCallBackProc=NewSndCallBackProc(SndCallBack1);
        if(!MATLAB){
            #if __MWERKS__
                // In CW4.5 _atexit() only gets called if you quit via abort() or exit().
                PatchExitToShell();
            #else
                _atexit(SndStop1);
            #endif
        }
        firstTime=0;
    }
    if(channel!=NULL)error=SndDisposeChannel(channel,FALSE);    // wait till done
    channel=NULL;
    if(error)return error;
    if(snd==NULL)return 0;
    error=SndNewChannel(&channel,0,0L,sndCallBackProc);
    if(error){
        printf("%s line %d:SndNewChannel failed with error %d\n",__FILE__,__LINE__,error);
        return error;
    }
    error=SndPlay(channel,snd,TRUE);
    if(error){
        printf("%s line %d:SndPlay failed with error %d\n",__FILE__,__LINE__,error);
        return error;
    }
    callBack.cmd=callBackCmd;
    callBack.param1=0;
    error=SndDoCommand(channel,&callBack,FALSE);
    if(error)printf("%s line %d:SndDoCommand failed with error %d\n",__FILE__,__LINE__,error);
    return error;
}

void SndStop1(void)
{
    if(channel!=NULL)SndDisposeChannel(channel,TRUE);        // immediately
    channel=NULL;
}

short SndDone1(void)
// Returns 1 if the last sound initiated by SndPlay1 has finished. Otherwise 0.
{
    return callBack.param1;
}

#if (THINK_C || THINK_CPLUS)
    #pragma options(!profile)    // Disable profiling because A5 may be invalid.
#endif

static pascal void SndCallBack1(SndChannelPtr channel,SndCommand command)
// Load a short int.
// Called back by sound manager.  Lets us know when sound is done.
{
    channel;    // prevent "unused argument" warning
    command.param1=1;
}

/*
The following code, which seems to work on 68k and ppc,
is based on examples that appeared in UseNet csmp-digest-v3-046
by Kevin Bell ([e-mail]) and Bill Hofmann ([e-mail])
in response to a query by Steve Coy ([e-mail])
*/

#if UNIVERSAL_HEADERS
    typedef UniversalProcPtr TrapAddressType;
#else
    #define UniversalProcPtr ProcPtr
    #define NewRoutineDescriptor(a,b,c) a
    typedef long TrapAddressType;
#endif
static UniversalProcPtr oldExitToShellTrapAddress=NULL;
static void PatchExitToShell(void);
static pascal void MyExitToShell(void);
#include <Traps.h>    // _ExitToShell

static void PatchExitToShell(void)
{
    UniversalProcPtr myExitToShellUPP;
    if(oldExitToShellTrapAddress==NULL){
        myExitToShellUPP=NewRoutineDescriptor((ProcPtr)MyExitToShell,kPascalStackBased,GetCurrentISA());
        oldExitToShellTrapAddress=(UniversalProcPtr)GetToolTrapAddress(_ExitToShell);
        SetToolTrapAddress((TrapAddressType)myExitToShellUPP,_ExitToShell);
    }
}

static pascal void MyExitToShell(void)
{
    SetCurrentA5();
    SetToolTrapAddress((TrapAddressType)oldExitToShellTrapAddress,_ExitToShell);
    SndStop1();
    ExitToShell();
}