refcnt.h

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#ifndef _GPXE_REFCNT_H
#define _GPXE_REFCNT_H

/** @file
 *
 * Reference counting
 *
 */

FILE_LICENCE ( GPL2_OR_LATER );

/**
 * A reference counter
 *
 * This data structure is designed to be embedded within a
 * reference-counted object.
 *
 * Reference-counted objects are freed when their reference count
 * drops below zero.  This means that a freshly allocated-and-zeroed
 * reference-counted object will be freed on the first call to
 * ref_put().
 */
struct refcnt {
        /** Current reference count
         *
         * When this count is decremented below zero, the free()
         * method will be called.
         */
        int refcnt;
        /** Free containing object
         *
         * This method is called when the reference count is
         * decremented below zero.
         *
         * If this method is left NULL, the standard library free()
         * function will be called.  The upshot of this is that you
         * may omit the free() method if the @c refcnt object is the
         * first element of your reference-counted struct.
         */
        void ( * free ) ( struct refcnt *refcnt );
};

extern struct refcnt * ref_get ( struct refcnt *refcnt );
extern void ref_put ( struct refcnt *refcnt );

#endif /* _GPXE_REFCNT_H */