Developer CD Series 1998 May: Tool Chest/Dev.CD May 98 TC.toast/Tool Chest/Development Kits/HyperCard Related/APDA HyperCard Toolkits/CD Audio Toolkit 1.0/Source/CDPlayTrack.c

C/C++ Source or Header | 1995-02-07 | 5.7 KB | 219 lines | [TEXT/MPS ]

/*
    CDPlayTrack - An XCMD to play an audio track.
    ©Apple Computer, Inc. 1988
    All Rights Reserved.

    88/10/08    BL°B    First Version

    To compile and link this file using Macintosh Programmer's Workshop,

    C -q2 CDPlayTrack.c
    link -sn Main=CDPlayTrack -sn STDIO=CDPlayTrack ∂
         -sn INTENV=CDPlayTrack -rt XFCN=42 ∂
         -m CDPLAYTRACK CDPlayTrack.c.o "{CLibraries}"CRuntime.o ∂
         "{CLibraries}"StdCLib.o ∂
         -o HyperCommands

    This link directive puts the XCMD in the file "HyperCommands".
    Substitute the name of the stack you want it in.  To move XCMDs
    between stacks, use ResEdit.  They can be in an individual stack,
    the Home stack, the HyperCard application, or the System File.

*/

#include <cd.h>

/* prototype definitions for functions */
void    ExtractTrackNo(char *, short *);
OSErr    APlay(XCmdBlockPtr, short, short);
OSErr    AStop(short, short);

/* **** WARNING:  DO NOT USE GLOBAL VARIABLES! **** */


/************************************************************************
 *
 *  Function:        CDPlayTrack
 *
 *  Purpose:        play an audio track
 *
 *  Returns:        result of driver call to play track
 *                    normally 0, but could have parameter error or
 *                    other error if non-existent track is specified
 *
 *  Side Effects:
 *
 *  Description:    We need one parameter, the track number.  Get
 *                    the global ioRefNum that we set by
 *                    previously calling CDOpen().  Extract the
 *                    track number and play it.
 *
 *                    If we get a second parameter, it is the stop track.
 *                    Issue a stop for that track.
 *
 ************************************************************************/
pascal void
CDPlayTrack(paramPtr)
    XCmdBlockPtr    paramPtr;
{
    Str31    returnString;
    OSErr    result;
    short    trackNumber;
    short    ioRefNum;
    Handle    refHandle;

    /* Must be one parameter (or possibly two*/
    if ((paramPtr->paramCount) != 1)
        if ((paramPtr->paramCount) != 2)
        {
            /* Report error in parameters by returning -1 */
            NumToStr(paramPtr, (long) -1, &returnString);
            paramPtr->returnValue = PasToZero(paramPtr, (StringPtr) &returnString);
            return;
        }

    /* Get the global ioRefNum and convert it. */
    refHandle = GetGlobal(paramPtr, GLOBALNAME);
    ioRefNum = atoi(*(refHandle));
    DisposHandle(refHandle);
    ioRefNum &= 0xFFFF;            /* remove vRefNum; not needed. */

    /* First param is track number.  Convert it to BCD */
    ExtractTrackNo((char *)*(paramPtr->params[0]), &trackNumber);

    result = APlay(paramPtr, trackNumber, ioRefNum);

    if (paramPtr->paramCount == 2 && result == noErr)
    {
        /* Second param is stopping track number.  Convert it to BCD */
        ExtractTrackNo((char *)*(paramPtr->params[1]), &trackNumber);

        result = AStop(trackNumber, ioRefNum);
    }

    /* Convert result to string & return it */
    NumToStr(paramPtr, (long) result, &returnString);
    paramPtr->returnValue = PasToZero(paramPtr, (StringPtr) &returnString);
}

/************************************************************************
 *
 *  Function:        ExtractTrackNo
 *
 *  Purpose:        Extract track number in BCD from PString
 *
 *  Returns:        nothing
 *
 *  Side Effects:    *track gets a new value
 *
 *  Description:    Extract track number in BCD from Cstring "name".
 *                    "name" is always of the form "XX", where XX
 *                    ranges from "1"  to "99"
 *                    (You can't have more than 99 tracks on a compact disc.
 *                    Bet you didn't know that, did you?  Right in the "Yellow
 *                    Book" specification of compact disc encoding.)
 *
 ************************************************************************/
void
ExtractTrackNo(name, track)
char        *name;
short        *track;
{
    short    t;

    t = 0;
    while (*name != 0)
    {
        t *= 16;
        t += *name - '0';
        name++;
    }

    *track = t;
}

/************************************************************************
 *
 *  Function:        APlay
 *
 *  Purpose:        start playing an audio track
 *
 *  Returns:        OSErr.  Probably either
 *                        noErr        everything's hunky-dory!
 *                        paramErr    you messed up the call somehow.
 *
 *  Side Effects:    starts play.  By default, this will play until the
 *                    end of the disc.
 *
 *  Description:    The track that you pass in is the first track that you
 *                    want to have play.
 *
 ************************************************************************/
OSErr
APlay(paramPtr, track, refNum)
XCmdBlockPtr    paramPtr;
short    track;
short    refNum;
{
    struct {
        short    addrFormat;
        long    address;
        short    stopAddress;
        short    playMode;
    }    csParam;
    short        playMode;
    Handle        refHandle;

    /* Get the global ioRefNum and convert it. */
    refHandle = GetGlobal(paramPtr, PLAYMODE);
    playMode = atoi(*(refHandle));
    DisposHandle(refHandle);

    csParam.addrFormat = TRACKADDR;
    csParam.address = track;    /* must be in BCD */
    csParam.stopAddress = 0;
    csParam.playMode = playMode;
    return (Control(refNum, APLAY, &csParam));
}


/************************************************************************
 *
 *  Function:        AStop
 *
 *  Purpose:        stop playing an audio track
 *
 *  Returns:        OSErr.  Probably either
 *                        noErr        everything's hunky-dory!
 *                        paramErr    you messed up the call somehow.
 *
 *  Side Effects:    stops play.
 *
 *  Description:    The track that you pass in is the LAST track that you
 *                    want to have play.  This means that if you wanted to
 *                    play only one track, you'd pass the same value to
 *                    this routine and APlay() [q.v.]
 *
 *                    Note that this routine isn't called in this sample,
 *                    but it's included for your enjoyment.
 *
 ************************************************************************/
OSErr
AStop(track, refNum)
short    track;
short    refNum;
{
    struct {
        short    addrFormat;
        long    address;
    }    csParam;

    csParam.addrFormat = TRACKADDR;
    csParam.address = track;
    return (Control(refNum, ASTOP, &csParam));
}


/* C routines for HyperCard callbacks */
#include <XCmdGlue.inc.c>