/*

    File:       TCycle.c

    Contains:   Definition of operations for TCycle, a cyclic list element datatype

    Copyright:  © 1997-1999 by Apple Computer, Inc., all rights reserved.

*/

#include "TCycle.h"

#include <MacMemory.h>

extern

TCycle **

CycleNew(

    unsigned long   inSize )

{

    TCycle **   cycleNew;

    if( inSize < sizeof( **cycleNew ) )

        inSize = sizeof( **cycleNew );

    cycleNew = ( TCycle ** ) NewHandle( inSize );

    if( cycleNew )

        ( **cycleNew ).__itsNext = cycleNew;

    return( cycleNew );

}

extern

void

CycleDispose(

    TCycle **   inElement )

{

    if( inElement )

    {

        if( ( **inElement ).__itsNext == inElement )

            DisposeHandle( ( Handle ) inElement );

    }

}

extern

TCycle **

CyclePut(

    TCycle **   inList,

    TCycle **   inElement )

{

    TCycle **   cyclePut = inList;

    if( inList  &&  inElement )

    {

        if( ( **inElement ).__itsNext == inElement )

        {

            ( **inElement ).__itsNext = ( **inList ).__itsNext;

            ( **inList ).__itsNext = inElement;

            cyclePut = inElement;

        }

    }

    return( cyclePut );

}

extern

TCycle **

CycleGet(

    TCycle **   inList )

{

    TCycle **   cycleGet = 0;

    if( inList )

    {

        cycleGet = ( **inList ).__itsNext;

        ( **inList ).__itsNext = ( **cycleGet ).__itsNext;

        ( **cycleGet ).__itsNext = cycleGet;

    }

    return( cycleGet );

}

extern

TCycle **

CycleNext(

    TCycle **   inElement )

{

    TCycle **   cycleNext = 0;

    if( inElement )

        cycleNext = ( **inElement ).__itsNext;

    return( cycleNext );

}