[babeltrace.git] / include / babeltrace / align.h

#ifndef _BABELTRACE_ALIGN_H
#define _BABELTRACE_ALIGN_H

/*
 * BabelTrace align.h - alignment header
 *
 * Copyright 2010 - 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.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <babeltrace/compiler.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

#define ALIGN(x, a)		__ALIGN_MASK(x, (typeof(x))(a) - 1)
#define __ALIGN_MASK(x, mask)	(((x) + (mask)) & ~(mask))
#define PTR_ALIGN(p, a)		((typeof(p)) ALIGN((unsigned long) (p), a))
#define ALIGN_FLOOR(x, a)	__ALIGN_FLOOR_MASK(x, (typeof(x)) (a) - 1)
#define __ALIGN_FLOOR_MASK(x, mask)	((x) & ~(mask))
#define PTR_ALIGN_FLOOR(p, a) \
			((typeof(p)) ALIGN_FLOOR((unsigned long) (p), a))
#define IS_ALIGNED(x, a)	(((x) & ((typeof(x)) (a) - 1)) == 0)

/*
 * Align pointer on natural object alignment.
 */
#define object_align(obj)	PTR_ALIGN(obj, __alignof__(*(obj)))
#define object_align_floor(obj)	PTR_ALIGN_FLOOR(obj, __alignof__(*(obj)))

/**
 * 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)				       \
	({								       \
		MAYBE_BUILD_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)			       \
	({								       \
		MAYBE_BUILD_BUG_ON((alignment) == 0			       \
				   || ((alignment) & ((alignment) - 1)));      \
		(((align_drift) - (alignment)) & ((alignment) - 1));	       \
	})

#endif /* _BABELTRACE_ALIGN_H */
Commit	Line	Data
d79865b9 MD	1	#ifndef _BABELTRACE_ALIGN_H
d79865b9 MD	2	#define _BABELTRACE_ALIGN_H
6dc2ca62	3
de0ba614	4	/*
d79865b9	5	* BabelTrace align.h - alignment header
de0ba614	6	*
ccd7e1c8	7	* Copyright 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
de0ba614	8	*
ccd7e1c8 MD	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:
de0ba614	15	*
ccd7e1c8 MD	16	* The above copyright notice and this permission notice shall be included in
ccd7e1c8 MD	17	* all copies or substantial portions of the Software.
c462e188 MD	18	*
	19	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	20	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	21	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	22	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	23	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	24	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
	25	* SOFTWARE.
de0ba614 MD	26	*/
de0ba614 MD	27
4c8bfb7e	28	#include <babeltrace/compiler.h>
c4f467da MD	29	#include <unistd.h>
	30	#include <limits.h>
	31
	32	#ifndef PAGE_SIZE /* Cygwin limits.h defines its own PAGE_SIZE */
	33	#define PAGE_SIZE sysconf(_SC_PAGE_SIZE)
	34	#endif
6dc2ca62 MD	35
	36	#define ALIGN(x, a) __ALIGN_MASK(x, (typeof(x))(a) - 1)
	37	#define __ALIGN_MASK(x, mask) (((x) + (mask)) & ~(mask))
	38	#define PTR_ALIGN(p, a) ((typeof(p)) ALIGN((unsigned long) (p), a))
	39	#define ALIGN_FLOOR(x, a) __ALIGN_FLOOR_MASK(x, (typeof(x)) (a) - 1)
	40	#define __ALIGN_FLOOR_MASK(x, mask) ((x) & ~(mask))
	41	#define PTR_ALIGN_FLOOR(p, a) \
	42	((typeof(p)) ALIGN_FLOOR((unsigned long) (p), a))
	43	#define IS_ALIGNED(x, a) (((x) & ((typeof(x)) (a) - 1)) == 0)
	44
	45	/*
	46	* Align pointer on natural object alignment.
	47	*/
	48	#define object_align(obj) PTR_ALIGN(obj, __alignof__(*(obj)))
	49	#define object_align_floor(obj) PTR_ALIGN_FLOOR(obj, __alignof__(*(obj)))
	50
	51	/**
	52	* offset_align - Calculate the offset needed to align an object on its natural
	53	* alignment towards higher addresses.
	54	* @align_drift: object offset from an "alignment"-aligned address.
	55	* @alignment: natural object alignment. Must be non-zero, power of 2.
	56	*
	57	* Returns the offset that must be added to align towards higher
	58	* addresses.
	59	*/
	60	#define offset_align(align_drift, alignment) \
	61	({ \
	62	MAYBE_BUILD_BUG_ON((alignment) == 0 \
	63	\|\| ((alignment) & ((alignment) - 1))); \
	64	(((alignment) - (align_drift)) & ((alignment) - 1)); \
	65	})
	66
	67	/**
	68	* offset_align_floor - Calculate the offset needed to align an object
	69	* on its natural alignment towards lower addresses.
	70	* @align_drift: object offset from an "alignment"-aligned address.
	71	* @alignment: natural object alignment. Must be non-zero, power of 2.
	72	*
	73	* Returns the offset that must be substracted to align towards lower addresses.
	74	*/
	75	#define offset_align_floor(align_drift, alignment) \
	76	({ \
	77	MAYBE_BUILD_BUG_ON((alignment) == 0 \
	78	\|\| ((alignment) & ((alignment) - 1))); \
23e78c03	79	(((align_drift) - (alignment)) & ((alignment) - 1)); \
6dc2ca62 MD	80	})
6dc2ca62 MD	81
d79865b9	82	#endif /* _BABELTRACE_ALIGN_H */