[lttng-tools.git] / src / common / align.hpp

/*
 * Copyright (C) 2010-2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * SPDX-License-Identifier: MIT
 *
 */

#ifndef _LTTNG_ALIGN_H
#define _LTTNG_ALIGN_H

#include "bug.hpp"

/*
 * Align value to the next multiple of align. Returns val if it already is a
 * multiple of align. Align must be a power of two.
 */
#define __lttng_align_ceil_mask(v, mask)	(((v) + (mask)) & ~(mask))

#define lttng_align_ceil(v, align) \
	__lttng_align_ceil_mask(v, (__typeof__(v)) (align) - 1)

/*
 * Align value to the previous multiple of align. Returns val if it already is a
 * multiple of align. Align must be a power of two.
 */
#define __lttng_align_floor_mask(v, mask)	((v) & ~(mask))

#define lttng_align_floor(v, align) \
	__lttng_align_floor_mask(v, (__typeof__(v)) (align) - 1)

/**
 * lttng_offset_align - Calculate the offset needed to align an object on its natural
 *                alignment towards higher addresses.
 * @align_drift:  object offset from an "alignment"-aligned address.
 * @alignment:    natural object alignment. Must be non-zero, power of 2.
 *
 * Returns the offset that must be added to align towards higher
 * addresses.
 */
#define lttng_offset_align(align_drift, alignment)				       \
	({								       \
		LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0		       \
				   || ((alignment) & ((alignment) - 1)));      \
		(((alignment) - (align_drift)) & ((alignment) - 1));	       \
	})

/**
 * lttng_offset_align_floor - Calculate the offset needed to align an object
 *                      on its natural alignment towards lower addresses.
 * @align_drift:  object offset from an "alignment"-aligned address.
 * @alignment:    natural object alignment. Must be non-zero, power of 2.
 *
 * Returns the offset that must be substracted to align towards lower addresses.
 */
#define lttng_offset_align_floor(align_drift, alignment)			       \
	({								       \
		LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0		       \
				   || ((alignment) & ((alignment) - 1)));      \
		(((align_drift) - (alignment)) & ((alignment) - 1));	       \
	})

#endif /* _LTTNG_ALIGN_H */
Commit	Line	Data
	1	/*
	2	* Copyright (C) 2010-2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	3	*
	4	* SPDX-License-Identifier: MIT
	5	*
	6	*/
	7
	8	#ifndef _LTTNG_ALIGN_H
	9	#define _LTTNG_ALIGN_H
	10
	11	#include "bug.hpp"
	12
	13	/*
	14	* Align value to the next multiple of align. Returns val if it already is a
	15	* multiple of align. Align must be a power of two.
	16	*/
	17	#define __lttng_align_ceil_mask(v, mask) (((v) + (mask)) & ~(mask))
	18
	19	#define lttng_align_ceil(v, align) \
	20	__lttng_align_ceil_mask(v, (__typeof__(v)) (align) - 1)
	21
	22	/*
	23	* Align value to the previous multiple of align. Returns val if it already is a
	24	* multiple of align. Align must be a power of two.
	25	*/
	26	#define __lttng_align_floor_mask(v, mask) ((v) & ~(mask))
	27
	28	#define lttng_align_floor(v, align) \
	29	__lttng_align_floor_mask(v, (__typeof__(v)) (align) - 1)
	30
	31	/**
	32	* lttng_offset_align - Calculate the offset needed to align an object on its natural
	33	* alignment towards higher addresses.
	34	* @align_drift: object offset from an "alignment"-aligned address.
	35	* @alignment: natural object alignment. Must be non-zero, power of 2.
	36	*
	37	* Returns the offset that must be added to align towards higher
	38	* addresses.
	39	*/
	40	#define lttng_offset_align(align_drift, alignment) \
	41	({ \
	42	LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0 \
	43	\|\| ((alignment) & ((alignment) - 1))); \
	44	(((alignment) - (align_drift)) & ((alignment) - 1)); \
	45	})
	46
	47	/**
	48	* lttng_offset_align_floor - Calculate the offset needed to align an object
	49	* on its natural alignment towards lower addresses.
	50	* @align_drift: object offset from an "alignment"-aligned address.
	51	* @alignment: natural object alignment. Must be non-zero, power of 2.
	52	*
	53	* Returns the offset that must be substracted to align towards lower addresses.
	54	*/
	55	#define lttng_offset_align_floor(align_drift, alignment) \
	56	({ \
	57	LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0 \
	58	\|\| ((alignment) & ((alignment) - 1))); \
	59	(((align_drift) - (alignment)) & ((alignment) - 1)); \
	60	})
	61
	62	#endif /* _LTTNG_ALIGN_H */