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#ifndef _REFERENCE_H_
#define _REFERENCE_H_
#include "reftypes.h"
#include <stddef.h>
#include <stdint.h>
#define container_of(ptr, type, member) \
((type *)((char *)(ptr) - (char *)&(((type *)NULL)->member)))
void ref_init( ref *reference, void ( *freefun )( ref * ), long count );
void ref_setref( weakref *weakref, ref *ref );
_Noreturn void _ref_error( const char *message );
static inline ref *ref_get( weakref *weakref )
{
char *old_weakref = (char *)*weakref;
do {
if ( old_weakref == NULL )
return NULL;
if ( aligned_ref( old_weakref ) != aligned_ref( old_weakref + 1 ) ) {
old_weakref = (char *)*weakref;
continue;
}
} while ( !atomic_compare_exchange_weak( weakref, (void **)&old_weakref, old_weakref + 1 ) );
struct _ref_ *ref = aligned_ref( old_weakref )->ref;
if ( unlikely( ++ref->count == -1 ) ) {
_ref_error( "Reference counter overflow. Aborting." );
}
char *cur_weakref = ( char * )*weakref;
do {
if ( aligned_ref( cur_weakref ) != aligned_ref( old_weakref ) ) {
ref->count--;
break;
}
} while ( !atomic_compare_exchange_weak( weakref, (void **)&cur_weakref, cur_weakref - 1 ) );
return ref;
}
static inline void ref_inc( ref *ref )
{
++ref->count;
}
static inline void ref_put( ref *ref )
{
if ( --ref->count == 0 ) {
ref->free( ref );
}
}
#define ref_get_uplink(wr) __extension__({ \
ref* ref = ref_get( wr ); \
ref == NULL ? NULL : container_of(ref, dnbd3_uplink_t, reference); \
})
#define ref_get_cachemap(image) __extension__({ \
ref* ref = ref_get( &(image)->ref_cacheMap ); \
ref == NULL ? NULL : container_of(ref, dnbd3_cache_map_t, reference); \
})
#endif
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