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

/*
 * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
 *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2 only,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#ifndef _MACROS_H
#define _MACROS_H

#include <stdlib.h>
#include <stddef.h>
#include <string.h>
#include <common/compat/string.h>

/*
 * Takes a pointer x and transform it so we can use it to access members
 * without a function call. Here an example:
 *
 *    #define GET_SIZE(x) LTTNG_REF(x)->size
 *
 *    struct { int size; } s;
 *
 *    printf("size : %d\n", GET_SIZE(&s));
 *
 * For this example we can't use something like this for compatibility purpose
 * since this will fail:
 *
 *    #define GET_SIZE(x) x->size;
 *
 * This is mostly use for the compatibility layer of lttng-tools. See
 * poll/epoll for a good example. Since x can be on the stack or allocated
 * memory using malloc(), we must use generic accessors for compat in order to
 * *not* use a function to access members and not the variable name.
 */
#define LTTNG_REF(x) ((typeof(*x) *)(x))

/*
 * Memory allocation zeroed
 */
static inline
void *zmalloc(size_t len)
{
	return calloc(1, len);
}

#ifndef ARRAY_SIZE
#define ARRAY_SIZE(array)   (sizeof(array) / (sizeof((array)[0])))
#endif

#ifndef container_of
#define container_of(ptr, type, member)					\
	({								\
		const typeof(((type *)NULL)->member) * __ptr = (ptr);	\
		(type *)((char *)__ptr - offsetof(type, member));	\
	})
#endif

#ifndef max
#define max(a, b) ((a) > (b) ? (a) : (b))
#endif

#ifndef max_t
#define max_t(type, a, b)	max((type) a, (type) b)
#endif

#ifndef min
#define min(a, b) ((a) < (b) ? (a) : (b))
#endif

#ifndef min_t
#define min_t(type, a, b)	min((type) a, (type) b)
#endif

#ifndef LTTNG_PACKED
#define LTTNG_PACKED __attribute__((__packed__))
#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 ALIGN_TO(value, align) ((value + (align - 1)) & ~(align - 1))

/*
 * LTTNG_HIDDEN: set the hidden attribute for internal functions
 * On Windows, symbols are local unless explicitly exported,
 * see https://gcc.gnu.org/wiki/Visibility
 */
#if defined(_WIN32) || defined(__CYGWIN__)
#define LTTNG_HIDDEN
#else
#define LTTNG_HIDDEN __attribute__((visibility("hidden")))
#endif

#define member_sizeof(type, field)	sizeof(((type *) 0)->field)

#define ASSERT_LOCKED(lock) assert(pthread_mutex_trylock(&lock))

/*
 * lttng_strncpy returns 0 on success, or nonzero on failure.
 * It checks that the @src string fits into @dst_len before performing
 * the copy. On failure, no copy has been performed.
 *
 * dst_len includes the string's trailing NULL.
 */
static inline
int lttng_strncpy(char *dst, const char *src, size_t dst_len)
{
	if (lttng_strnlen(src, dst_len) >= dst_len) {
		/* Fail since copying would result in truncation. */
		return -1;
	}
	strcpy(dst, src);
	return 0;
}

#endif /* _MACROS_H */
Commit	Line	Data
	1	/*
	2	* Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
	3	* Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	4	*
	5	* This program is free software; you can redistribute it and/or modify
	6	* it under the terms of the GNU General Public License, version 2 only,
	7	* as published by the Free Software Foundation.
	8	*
	9	* This program is distributed in the hope that it will be useful, but WITHOUT
	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	12	* more details.
	13	*
	14	* You should have received a copy of the GNU General Public License along
	15	* with this program; if not, write to the Free Software Foundation, Inc.,
	16	* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
	17	*/
	18
	19	#ifndef _MACROS_H
	20	#define _MACROS_H
	21
	22	#include <stdlib.h>
	23	#include <stddef.h>
	24	#include <string.h>
	25	#include <common/compat/string.h>
	26
	27	/*
	28	* Takes a pointer x and transform it so we can use it to access members
	29	* without a function call. Here an example:
	30	*
	31	* #define GET_SIZE(x) LTTNG_REF(x)->size
	32	*
	33	* struct { int size; } s;
	34	*
	35	* printf("size : %d\n", GET_SIZE(&s));
	36	*
	37	* For this example we can't use something like this for compatibility purpose
	38	* since this will fail:
	39	*
	40	* #define GET_SIZE(x) x->size;
	41	*
	42	* This is mostly use for the compatibility layer of lttng-tools. See
	43	* poll/epoll for a good example. Since x can be on the stack or allocated
	44	* memory using malloc(), we must use generic accessors for compat in order to
	45	* not use a function to access members and not the variable name.
	46	*/
	47	#define LTTNG_REF(x) ((typeof(x) )(x))
	48
	49	/*
	50	* Memory allocation zeroed
	51	*/
	52	static inline
	53	void *zmalloc(size_t len)
	54	{
	55	return calloc(1, len);
	56	}
	57
	58	#ifndef ARRAY_SIZE
	59	#define ARRAY_SIZE(array) (sizeof(array) / (sizeof((array)[0])))
	60	#endif
	61
	62	#ifndef container_of
	63	#define container_of(ptr, type, member) \
	64	({ \
	65	const typeof(((type )NULL)->member) __ptr = (ptr); \
	66	(type )((char )__ptr - offsetof(type, member)); \
	67	})
	68	#endif
	69
	70	#ifndef max
	71	#define max(a, b) ((a) > (b) ? (a) : (b))
	72	#endif
	73
	74	#ifndef max_t
	75	#define max_t(type, a, b) max((type) a, (type) b)
	76	#endif
	77
	78	#ifndef min
	79	#define min(a, b) ((a) < (b) ? (a) : (b))
	80	#endif
	81
	82	#ifndef min_t
	83	#define min_t(type, a, b) min((type) a, (type) b)
	84	#endif
	85
	86	#ifndef LTTNG_PACKED
	87	#define LTTNG_PACKED __attribute__((__packed__))
	88	#endif
	89
	90	/*
	91	* Align value to the next multiple of align. Returns val if it already is a
	92	* multiple of align. Align must be a power of two.
	93	*/
	94	#define ALIGN_TO(value, align) ((value + (align - 1)) & ~(align - 1))
	95
	96	/*
	97	* LTTNG_HIDDEN: set the hidden attribute for internal functions
	98	* On Windows, symbols are local unless explicitly exported,
	99	* see https://gcc.gnu.org/wiki/Visibility
	100	*/
	101	#if defined(_WIN32) \|\| defined(__CYGWIN__)
	102	#define LTTNG_HIDDEN
	103	#else
	104	#define LTTNG_HIDDEN __attribute__((visibility("hidden")))
	105	#endif
	106
	107	#define member_sizeof(type, field) sizeof(((type *) 0)->field)
	108
	109	#define ASSERT_LOCKED(lock) assert(pthread_mutex_trylock(&lock))
	110
	111	/*
	112	* lttng_strncpy returns 0 on success, or nonzero on failure.
	113	* It checks that the @src string fits into @dst_len before performing
	114	* the copy. On failure, no copy has been performed.
	115	*
	116	* dst_len includes the string's trailing NULL.
	117	*/
	118	static inline
	119	int lttng_strncpy(char dst, const char src, size_t dst_len)
	120	{
	121	if (lttng_strnlen(src, dst_len) >= dst_len) {
	122	/* Fail since copying would result in truncation. */
	123	return -1;
	124	}
	125	strcpy(dst, src);
	126	return 0;
	127	}
	128
	129	#endif /* _MACROS_H */