#ifndef _UST_ALIGN_H

#define _UST_ALIGN_H

/*

 * lttng/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.

 *

 * 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 <lttng/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

#define PAGE_MASK		(~(PAGE_SIZE - 1))

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

#define ALIGN(v, align)		__ALIGN_MASK(v, (__typeof__(v)) (align) - 1)

#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 /* _UST_ALIGN_H */