[apple/libc.git] / include / struct.h

/*-
 * Copyright (c) 1983, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)struct.h	8.1 (Berkeley) 6/2/93
 */

#ifndef _STRUCT_H_
#define	_STRUCT_H_

/* Offset of the field in the structure. */
#define	fldoff(name, field) \
	((int)&(((struct name *)0)->field))

/* Size of the field in the structure. */
#define	fldsiz(name, field) \
	(sizeof(((struct name *)0)->field))

/* Address of the structure from a field. */
#define	strbase(name, addr, field) \
	((struct name *)((char *)(addr) - fldoff(name, field)))

/*
 * countof() cannot be safely used in a _Static_assert statement, so we provide
 * an unsafe variant that does not verify the input array is statically-defined.
 */
#define countof_unsafe(arr) \
	(sizeof(arr) / sizeof(arr[0]))

/* Number of elements in a statically-defined array */
#if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L && __GNUC__
#define countof(arr) ({ \
	_Static_assert( \
			!__builtin_types_compatible_p(typeof(arr), typeof(&(arr)[0])), \
			"array must be statically defined"); \
	(sizeof(arr) / sizeof(arr[0])); \
})
#else
#define countof(arr) \
	countof_unsafe(arr)
#endif

/* Length of a statically-defined string (does not include null terminator) */
#define lenof(str) \
	(sizeof(str) - 1)

/* Last index of a statically-defined array */
#define lastof(arr) \
	(countof(arr) - 1)

#endif /* !_STRUCT_H_ */
Commit	Line	Data
5b2abdfb	1	/*-
e9ce8d39 A	2	* Copyright (c) 1983, 1993
	3	* The Regents of the University of California. All rights reserved.
	4	*
	5	* Redistribution and use in source and binary forms, with or without
	6	* modification, are permitted provided that the following conditions
	7	* are met:
	8	* 1. Redistributions of source code must retain the above copyright
	9	* notice, this list of conditions and the following disclaimer.
	10	* 2. Redistributions in binary form must reproduce the above copyright
	11	* notice, this list of conditions and the following disclaimer in the
	12	* documentation and/or other materials provided with the distribution.
	13	* 3. All advertising materials mentioning features or use of this software
	14	* must display the following acknowledgement:
	15	* This product includes software developed by the University of
	16	* California, Berkeley and its contributors.
	17	* 4. Neither the name of the University nor the names of its contributors
	18	* may be used to endorse or promote products derived from this software
	19	* without specific prior written permission.
	20	*
	21	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	22	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	23	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	24	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	25	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	26	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	27	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	28	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	29	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	30	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	31	* SUCH DAMAGE.
5b2abdfb A	32	*
5b2abdfb A	33	* @(#)struct.h 8.1 (Berkeley) 6/2/93
e9ce8d39 A	34	*/
e9ce8d39 A	35
5b2abdfb A	36	#ifndef _STRUCT_H_
	37	#define _STRUCT_H_
	38
	39	/* Offset of the field in the structure. */
	40	#define fldoff(name, field) \
	41	((int)&(((struct name *)0)->field))
e9ce8d39	42
5b2abdfb A	43	/* Size of the field in the structure. */
	44	#define fldsiz(name, field) \
	45	(sizeof(((struct name *)0)->field))
e9ce8d39	46
5b2abdfb A	47	/* Address of the structure from a field. */
	48	#define strbase(name, addr, field) \
	49	((struct name )((char )(addr) - fldoff(name, field)))
e9ce8d39	50
e1ee4b85 A	51	/*
	52	* countof() cannot be safely used in a _Static_assert statement, so we provide
	53	* an unsafe variant that does not verify the input array is statically-defined.
	54	*/
	55	#define countof_unsafe(arr) \
	56	(sizeof(arr) / sizeof(arr[0]))
	57
70ad1dc8 A	58	/* Number of elements in a statically-defined array */
	59	#if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L && __GNUC__
	60	#define countof(arr) ({ \
	61	_Static_assert( \
	62	!__builtin_types_compatible_p(typeof(arr), typeof(&(arr)[0])), \
	63	"array must be statically defined"); \
	64	(sizeof(arr) / sizeof(arr[0])); \
	65	})
	66	#else
	67	#define countof(arr) \
e1ee4b85	68	countof_unsafe(arr)
70ad1dc8 A	69	#endif
	70
	71	/* Length of a statically-defined string (does not include null terminator) */
	72	#define lenof(str) \
	73	(sizeof(str) - 1)
	74
e1ee4b85 A	75	/* Last index of a statically-defined array */
	76	#define lastof(arr) \
	77	(countof(arr) - 1)
	78
5b2abdfb	79	#endif /* !_STRUCT_H_ */