[audio-libsamplerate.git] / libsamplerate / M4 / endian.m4

dnl @synopsis AC_C_FIND_ENDIAN
dnl
dnl Determine endian-ness of target processor.
dnl @version 1.1	Mar 03 2002
dnl @author Erik de Castro Lopo <erikd AT mega-nerd DOT com>
dnl
dnl Majority written from scratch to replace the standard autoconf macro 
dnl AC_C_BIGENDIAN. Only part remaining from the original it the invocation
dnl of the AC_TRY_RUN macro.
dnl
dnl Permission to use, copy, modify, distribute, and sell this file for any 
dnl purpose is hereby granted without fee, provided that the above copyright 
dnl and this permission notice appear in all copies.  No representations are
dnl made about the suitability of this software for any purpose.  It is 
dnl provided "as is" without express or implied warranty.

dnl Find endian-ness in the following way:
dnl    1) Look in <endian.h>.
dnl    2) If 1) fails, look in <sys/types.h> and <sys/param.h>.
dnl    3) If 1) and 2) fails and not cross compiling run a test program.
dnl    4) If 1) and 2) fails and cross compiling then guess based on target.

AC_DEFUN([AC_C_FIND_ENDIAN],
[AC_CACHE_CHECK(processor byte ordering, 
	ac_cv_c_byte_order,

# Initialize to unknown
ac_cv_c_byte_order=unknown

if test x$ac_cv_header_endian_h = xyes ; then

	# First try <endian.h> which should set BYTE_ORDER.

	[AC_TRY_LINK([
		#include <endian.h>
		#if BYTE_ORDER != LITTLE_ENDIAN
			not big endian
		#endif
		], return 0 ;, 
			ac_cv_c_byte_order=little
		)]
				
	[AC_TRY_LINK([
		#include <endian.h>
		#if BYTE_ORDER != BIG_ENDIAN
			not big endian
		#endif
		], return 0 ;, 
			ac_cv_c_byte_order=big
		)]

	fi

if test $ac_cv_c_byte_order = unknown ; then

	[AC_TRY_LINK([
		#include <sys/types.h>
		#include <sys/param.h>
		#if !BYTE_ORDER || !BIG_ENDIAN || !LITTLE_ENDIAN
			bogus endian macros
		#endif
		], return 0 ;, 

		[AC_TRY_LINK([
			#include <sys/types.h>
			#include <sys/param.h>
			#if BYTE_ORDER != LITTLE_ENDIAN
				not big endian
			#endif
			], return 0 ;, 
				ac_cv_c_byte_order=little
			)]
				
		[AC_TRY_LINK([
			#include <sys/types.h>
			#include <sys/param.h>
			#if BYTE_ORDER != LITTLE_ENDIAN
				not big endian
			#endif
			], return 0 ;, 
				ac_cv_c_byte_order=little
			)]

		)]

 	fi

if test $ac_cv_c_byte_order = unknown ; then
	if test $cross_compiling = yes ; then
		# This is the last resort. Try to guess the target processor endian-ness
		# by looking at the target CPU type.	
		[
		case "$target_cpu" in
			alpha* | i?86* | mipsel* | ia64*)
				ac_cv_c_byte_order=little
				;;
			
			m68* | mips* | powerpc* | hppa* | sparc*)
				ac_cv_c_byte_order=big
				;;
	
			esac
		]
	else
		AC_TRY_RUN(
		[[
		int main (void) 
		{	/* Are we little or big endian?  From Harbison&Steele.  */
			union
			{	long l ;
				char c [sizeof (long)] ;
			} u ;
			u.l = 1 ;
			return (u.c [sizeof (long) - 1] == 1);
			}
			]], , ac_cv_c_byte_order=big, 
			)

		AC_TRY_RUN(
		[[int main (void) 
		{	/* Are we little or big endian?  From Harbison&Steele.  */
			union
			{	long l ;
				char c [sizeof (long)] ;
			} u ;
			u.l = 1 ;
			return (u.c [0] == 1);
			}]], , ac_cv_c_byte_order=little, 
			)
		fi	
	fi

)

if test $ac_cv_c_byte_order = big ; then
	ac_cv_c_big_endian=1
	ac_cv_c_little_endian=0
elif test $ac_cv_c_byte_order = little ; then
	ac_cv_c_big_endian=0
	ac_cv_c_little_endian=1
else
	ac_cv_c_big_endian=0
	ac_cv_c_little_endian=0

	AC_MSG_WARN([[*****************************************************************]])
	AC_MSG_WARN([[*** Not able to determine endian-ness of target processor.       ]])
	AC_MSG_WARN([[*** The constants CPU_IS_BIG_ENDIAN and CPU_IS_LITTLE_ENDIAN in  ]])
	AC_MSG_WARN([[*** src/config.h may need to be hand editied.                    ]])
	AC_MSG_WARN([[*****************************************************************]])
	fi

]
)# AC_C_FIND_ENDIAN
Commit	Line	Data
	1	dnl @synopsis AC_C_FIND_ENDIAN
	2	dnl
	3	dnl Determine endian-ness of target processor.
	4	dnl @version 1.1 Mar 03 2002
	5	dnl @author Erik de Castro Lopo <erikd AT mega-nerd DOT com>
	6	dnl
	7	dnl Majority written from scratch to replace the standard autoconf macro
	8	dnl AC_C_BIGENDIAN. Only part remaining from the original it the invocation
	9	dnl of the AC_TRY_RUN macro.
	10	dnl
	11	dnl Permission to use, copy, modify, distribute, and sell this file for any
	12	dnl purpose is hereby granted without fee, provided that the above copyright
	13	dnl and this permission notice appear in all copies. No representations are
	14	dnl made about the suitability of this software for any purpose. It is
	15	dnl provided "as is" without express or implied warranty.
	16
	17	dnl Find endian-ness in the following way:
	18	dnl 1) Look in <endian.h>.
	19	dnl 2) If 1) fails, look in <sys/types.h> and <sys/param.h>.
	20	dnl 3) If 1) and 2) fails and not cross compiling run a test program.
	21	dnl 4) If 1) and 2) fails and cross compiling then guess based on target.
	22
	23	AC_DEFUN([AC_C_FIND_ENDIAN],
	24	[AC_CACHE_CHECK(processor byte ordering,
	25	ac_cv_c_byte_order,
	26
	27	# Initialize to unknown
	28	ac_cv_c_byte_order=unknown
	29
	30	if test x$ac_cv_header_endian_h = xyes ; then
	31
	32	# First try <endian.h> which should set BYTE_ORDER.
	33
	34	[AC_TRY_LINK([
	35	#include <endian.h>
	36	#if BYTE_ORDER != LITTLE_ENDIAN
	37	not big endian
	38	#endif
	39	], return 0 ;,
	40	ac_cv_c_byte_order=little
	41	)]
	42
	43	[AC_TRY_LINK([
	44	#include <endian.h>
	45	#if BYTE_ORDER != BIG_ENDIAN
	46	not big endian
	47	#endif
	48	], return 0 ;,
	49	ac_cv_c_byte_order=big
	50	)]
	51
	52	fi
	53
	54	if test $ac_cv_c_byte_order = unknown ; then
	55
	56	[AC_TRY_LINK([
	57	#include <sys/types.h>
	58	#include <sys/param.h>
	59	#if !BYTE_ORDER \|\| !BIG_ENDIAN \|\| !LITTLE_ENDIAN
	60	bogus endian macros
	61	#endif
	62	], return 0 ;,
	63
	64	[AC_TRY_LINK([
	65	#include <sys/types.h>
	66	#include <sys/param.h>
	67	#if BYTE_ORDER != LITTLE_ENDIAN
	68	not big endian
	69	#endif
	70	], return 0 ;,
	71	ac_cv_c_byte_order=little
	72	)]
	73
	74	[AC_TRY_LINK([
	75	#include <sys/types.h>
	76	#include <sys/param.h>
	77	#if BYTE_ORDER != LITTLE_ENDIAN
	78	not big endian
	79	#endif
	80	], return 0 ;,
	81	ac_cv_c_byte_order=little
	82	)]
	83
	84	)]
	85
	86	fi
	87
	88	if test $ac_cv_c_byte_order = unknown ; then
	89	if test $cross_compiling = yes ; then
	90	# This is the last resort. Try to guess the target processor endian-ness
	91	# by looking at the target CPU type.
	92	[
	93	case "$target_cpu" in
	94	alpha* \| i?86* \| mipsel* \| ia64*)
	95	ac_cv_c_byte_order=little
	96	;;
	97
	98	m68* \| mips* \| powerpc* \| hppa* \| sparc*)
	99	ac_cv_c_byte_order=big
	100	;;
	101
	102	esac
	103	]
	104	else
	105	AC_TRY_RUN(
	106	[[
	107	int main (void)
	108	{ /* Are we little or big endian? From Harbison&Steele. */
	109	union
	110	{ long l ;
	111	char c [sizeof (long)] ;
	112	} u ;
	113	u.l = 1 ;
	114	return (u.c [sizeof (long) - 1] == 1);
	115	}
	116	]], , ac_cv_c_byte_order=big,
	117	)
	118
	119	AC_TRY_RUN(
	120	[[int main (void)
	121	{ /* Are we little or big endian? From Harbison&Steele. */
	122	union
	123	{ long l ;
	124	char c [sizeof (long)] ;
	125	} u ;
	126	u.l = 1 ;
	127	return (u.c [0] == 1);
	128	}]], , ac_cv_c_byte_order=little,
	129	)
	130	fi
	131	fi
	132
	133	)
	134
	135	if test $ac_cv_c_byte_order = big ; then
	136	ac_cv_c_big_endian=1
	137	ac_cv_c_little_endian=0
	138	elif test $ac_cv_c_byte_order = little ; then
	139	ac_cv_c_big_endian=0
	140	ac_cv_c_little_endian=1
	141	else
	142	ac_cv_c_big_endian=0
	143	ac_cv_c_little_endian=0
	144
	145	AC_MSG_WARN([[*****************************************************************]])
	146	AC_MSG_WARN([[*** Not able to determine endian-ness of target processor. ]])
	147	AC_MSG_WARN([[*** The constants CPU_IS_BIG_ENDIAN and CPU_IS_LITTLE_ENDIAN in ]])
	148	AC_MSG_WARN([[*** src/config.h may need to be hand editied. ]])
	149	AC_MSG_WARN([[*****************************************************************]])
	150	fi
	151
	152	]
	153	)# AC_C_FIND_ENDIAN
	154
	155