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

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

#ifndef _LTTNG_ALIGN_H
#define _LTTNG_ALIGN_H

#include "bug.h"
#include <unistd.h>
#include <limits.h>

#ifndef PAGE_SIZE	/* Cygwin limits.h defines its own PAGE_SIZE. */
#define PAGE_SIZE		sysconf(_SC_PAGE_SIZE)
#endif


/*
 * 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
953192ba	1	/*
ab5be9fa	2	* Copyright (C) 2010-2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
953192ba	3	*
ab5be9fa	4	* SPDX-License-Identifier: MIT
953192ba	5	*
953192ba MD	6	*/
953192ba MD	7
ab5be9fa MJ	8	#ifndef _LTTNG_ALIGN_H
	9	#define _LTTNG_ALIGN_H
	10
8564ccbd	11	#include "bug.h"
953192ba MD	12	#include <unistd.h>
	13	#include <limits.h>
	14
d575a7f8	15	#ifndef PAGE_SIZE /* Cygwin limits.h defines its own PAGE_SIZE. */
953192ba MD	16	#define PAGE_SIZE sysconf(_SC_PAGE_SIZE)
	17	#endif
	18
d575a7f8	19
1cbd136b MJ	20	/*
	21	* Align value to the next multiple of align. Returns val if it already is a
	22	* multiple of align. Align must be a power of two.
	23	*/
	24	#define __lttng_align_ceil_mask(v, mask) (((v) + (mask)) & ~(mask))
d575a7f8	25
1cbd136b MJ	26	#define lttng_align_ceil(v, align) \
1cbd136b MJ	27	__lttng_align_ceil_mask(v, (__typeof__(v)) (align) - 1)
d4ad24a3	28
1cbd136b MJ	29	/*
	30	* Align value to the previous multiple of align. Returns val if it already is a
	31	* multiple of align. Align must be a power of two.
	32	*/
	33	#define __lttng_align_floor_mask(v, mask) ((v) & ~(mask))
d4ad24a3	34
1cbd136b MJ	35	#define lttng_align_floor(v, align) \
1cbd136b MJ	36	__lttng_align_floor_mask(v, (__typeof__(v)) (align) - 1)
953192ba MD	37
953192ba MD	38	/**
1cbd136b	39	* lttng_offset_align - Calculate the offset needed to align an object on its natural
953192ba MD	40	* alignment towards higher addresses.
	41	* @align_drift: object offset from an "alignment"-aligned address.
	42	* @alignment: natural object alignment. Must be non-zero, power of 2.
	43	*
	44	* Returns the offset that must be added to align towards higher
	45	* addresses.
	46	*/
1cbd136b	47	#define lttng_offset_align(align_drift, alignment) \
953192ba MD	48	({ \
	49	LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0 \
	50	\|\| ((alignment) & ((alignment) - 1))); \
	51	(((alignment) - (align_drift)) & ((alignment) - 1)); \
	52	})
	53
	54	/**
1cbd136b	55	* lttng_offset_align_floor - Calculate the offset needed to align an object
953192ba MD	56	* on its natural alignment towards lower addresses.
	57	* @align_drift: object offset from an "alignment"-aligned address.
	58	* @alignment: natural object alignment. Must be non-zero, power of 2.
	59	*
	60	* Returns the offset that must be substracted to align towards lower addresses.
	61	*/
1cbd136b	62	#define lttng_offset_align_floor(align_drift, alignment) \
953192ba MD	63	({ \
	64	LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0 \
	65	\|\| ((alignment) & ((alignment) - 1))); \
d07ceecd	66	(((align_drift) - (alignment)) & ((alignment) - 1)); \
953192ba MD	67	})
	68
	69	#endif /* _LTTNG_ALIGN_H */