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

#ifndef _LTTNG_ALIGN_H
#define _LTTNG_ALIGN_H

/*
 * align.h
 *
 * (C) Copyright 2010-2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 */

#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

#ifndef PAGE_MASK	/* macOS defines its own PAGE_MASK. */
#define PAGE_MASK		(~(PAGE_SIZE - 1))
#endif

#define __ALIGN_MASK(v, mask)	(((v) + (mask)) & ~(mask))

#ifndef ALIGN		/* macOS defines its own ALIGN. */
#define ALIGN(v, align)		__ALIGN_MASK(v, (__typeof__(v)) (align) - 1)
#endif

#define __ALIGN_FLOOR_MASK(v, mask)	((v) & ~(mask))

#ifndef ALIGN_FLOOR
#define ALIGN_FLOOR(v, align)	__ALIGN_FLOOR_MASK(v, (__typeof__(v)) (align) - 1)
#endif

#define PAGE_ALIGN(addr)	ALIGN(addr, PAGE_SIZE)

/**
 * 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 offset_align(align_drift, alignment)				       \
	({								       \
		LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0		       \
				   || ((alignment) & ((alignment) - 1)));      \
		(((alignment) - (align_drift)) & ((alignment) - 1));	       \
	})

/**
 * 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 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	#ifndef _LTTNG_ALIGN_H
	2	#define _LTTNG_ALIGN_H
	3
	4	/*
	5	* align.h
	6	*
	7	* (C) Copyright 2010-2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	8	*
	9	* Permission is hereby granted, free of charge, to any person obtaining a copy
	10	* of this software and associated documentation files (the "Software"), to deal
	11	* in the Software without restriction, including without limitation the rights
	12	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	13	* copies of the Software, and to permit persons to whom the Software is
	14	* furnished to do so, subject to the following conditions:
	15	*
	16	* The above copyright notice and this permission notice shall be included in
	17	* all copies or substantial portions of the Software.
	18	*/
	19
	20	#include "bug.h"
	21	#include <unistd.h>
	22	#include <limits.h>
	23
	24	#ifndef PAGE_SIZE /* Cygwin limits.h defines its own PAGE_SIZE. */
	25	#define PAGE_SIZE sysconf(_SC_PAGE_SIZE)
	26	#endif
	27
	28	#ifndef PAGE_MASK /* macOS defines its own PAGE_MASK. */
	29	#define PAGE_MASK (~(PAGE_SIZE - 1))
	30	#endif
	31
	32	#define __ALIGN_MASK(v, mask) (((v) + (mask)) & ~(mask))
	33
	34	#ifndef ALIGN /* macOS defines its own ALIGN. */
	35	#define ALIGN(v, align) __ALIGN_MASK(v, (__typeof__(v)) (align) - 1)
	36	#endif
	37
	38	#define __ALIGN_FLOOR_MASK(v, mask) ((v) & ~(mask))
	39
	40	#ifndef ALIGN_FLOOR
	41	#define ALIGN_FLOOR(v, align) __ALIGN_FLOOR_MASK(v, (__typeof__(v)) (align) - 1)
	42	#endif
	43
	44	#define PAGE_ALIGN(addr) ALIGN(addr, PAGE_SIZE)
	45
	46	/**
	47	* offset_align - Calculate the offset needed to align an object on its natural
	48	* alignment towards higher addresses.
	49	* @align_drift: object offset from an "alignment"-aligned address.
	50	* @alignment: natural object alignment. Must be non-zero, power of 2.
	51	*
	52	* Returns the offset that must be added to align towards higher
	53	* addresses.
	54	*/
	55	#define offset_align(align_drift, alignment) \
	56	({ \
	57	LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0 \
	58	\|\| ((alignment) & ((alignment) - 1))); \
	59	(((alignment) - (align_drift)) & ((alignment) - 1)); \
	60	})
	61
	62	/**
	63	* offset_align_floor - Calculate the offset needed to align an object
	64	* on its natural alignment towards lower addresses.
	65	* @align_drift: object offset from an "alignment"-aligned address.
	66	* @alignment: natural object alignment. Must be non-zero, power of 2.
	67	*
	68	* Returns the offset that must be substracted to align towards lower addresses.
	69	*/
	70	#define offset_align_floor(align_drift, alignment) \
	71	({ \
	72	LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0 \
	73	\|\| ((alignment) & ((alignment) - 1))); \
	74	(((align_drift) - (alignment)) & ((alignment) - 1)); \
	75	})
	76
	77	#endif /* _LTTNG_ALIGN_H */