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palm/palm_locking.c

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#include <PalmOS.h>
#include <StringMgr.h>
#include <globals.h>
#include <locking.h>
#include <mem_compat.h>

static struct tag_lockers {
        MemHandle       handle; 
        int             lockcount; 
        void            **destVar; 
} lockZones[lz_end] = {
        { NULL, 0, &worldPtr },
        { NULL, 0, &flagPtr },
        { NULL, 0, &growablePtr }
};

void
LockZone(lockZone zone)
{
        struct tag_lockers *lock = lockZones + zone;

        lock->lockcount += 1;
        if (lock->lockcount == 1) {
                if (lock->handle) {
                        MemPtr mp = MemHandleLock(lock->handle);
                        *(lock->destVar) = mp;
                }
                lock->handle = NULL;
        }
}

void
ReleaseZone(lockZone zone)
{
        struct tag_lockers *lock = lockZones + zone;

        LockZone(zone);
        if (*lock->destVar != NULL) {
                MemPtrFree(*lock->destVar);
        }
        lock->handle = NULL;
        lock->destVar = NULL;
        lock->lockcount = 0;
}

void
UnlockZone(lockZone zone)
{
        struct tag_lockers *lock = lockZones + zone;
        MemPtr mp = *lock->destVar;

        if (mp != NULL) {
                lock->handle = MemPtrRecoverHandle(mp);
        }
        lock->lockcount -= 1;
        if (lock->lockcount == 0) {
                if (mp != NULL)
                        MemHandleUnlock(lock->handle);
                *lock->destVar = NULL;
        }

        ErrFatalDisplayIf(lock->lockcount < 0,
            "Too many unlock calls");
}

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