core/lock.h

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#ifndef _LOCK_H
#define _LOCK_H

#include "object.h"

#ifdef WIN32
    #include <intrin.h>
    #pragma intrinsic(_InterlockedCompareExchange)
    #define cmpxchg(dest, xchg, comp) ((unsigned long) _InterlockedCompareExchange((long *) dest, (long) xchg, (long) comp))
    #define HAVE_CMPXCHG
#elif __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ >= 1050
    #include <libkern/OSAtomic.h>
    #define cmpxchg(dest, xchg, comp) (OSAtomicCompareAndSwapLong((long) comp, (long) xchg, (long *) dest) ? xchg : comp)
    #define HAVE_CMPXCHG
#else
    #define cmpxchg(dest, xchg, comp) __sync_val_compare_and_swap(dest, comp, xchg)
    #define HAVE_CMPXCHG
#endif /* defined(WIN32) */

#ifndef HAVE_CMPXCHG
    #define NOLOCKS 1
#endif /* !defined(CMPXCHG) */

#ifdef NOLOCKS
    #define LOCK(flags)
    #define UNLOCK(flags)
    #define LOCK_OBJECT(obj)
    #define UNLOCK_OBJECT(obj)
    #define LOCKED(obj, command)
#else /* !defined(NOLOCKS) */

static __inline int lock(unsigned long *flags)
{
    unsigned int f;
    register int spin=0;
    do {
        spin++;
        f = *flags;
    } while (f & OF_LOCKED || cmpxchg(flags, f | OF_LOCKED, f) & OF_LOCKED);
    return spin;
}

static __inline void unlock(unsigned long *flags)
{
    unsigned int f;

    do {
        f = *flags;
    } while (f & OF_LOCKED && cmpxchg(flags, f ^ OF_LOCKED, f) != f);
}

#define LOCK(flags) ((*(callback->lock_count))++, (*(callback->lock_spin))+=lock(flags)) 
#define UNLOCK(flags) unlock(flags) 
#define LOCK_OBJECT(obj) ((*(callback->lock_count))++, (*(callback->lock_spin))+=lock(&((obj)->flags))) 
#define UNLOCK_OBJECT(obj) unlock(&((obj)->flags)) 
#define LOCKED(obj,command) (LOCK_OBJECT(obj),(command),UNLOCK_OBJECT(obj))

#endif /* defined(NOLOCKS) */

#endif /* _LOCK_H */

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