intprops.h		intprops.h
	/* intprops.h -- properties of integer types		/* intprops.h -- properties of integer types
	Copyright (C) 2001, 2002, 2003, 2004, 2005, 2009, 2010 Free Software		Copyright (C) 2001-2005, 2009-2014 Free Software Foundation, Inc.
	Foundation, Inc.
	This program is free software: you can redistribute it and/or modify		This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by		it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 3 of the License, or		the Free Software Foundation; either version 3 of the License, or
	(at your option) any later version.		(at your option) any later version.
	This program is distributed in the hope that it will be useful,		This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of		but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the		MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	GNU General Public License for more details.		GNU General Public License for more details.
	You should have received a copy of the GNU General Public License		You should have received a copy of the GNU General Public License
	along with this program. If not, see <http://www.gnu.org/licenses/>. * /		along with this program. If not, see <http://www.gnu.org/licenses/>. * /
	/* Written by Paul Eggert. */		/* Written by Paul Eggert. */
	#ifndef GL_INTPROPS_H		#ifndef _GL_INTPROPS_H
	# define GL_INTPROPS_H		#define _GL_INTPROPS_H
	# include <limits.h>		#include <limits.h>
			/* Return an integer value, converted to the same type as the integer
			expression E after integer type promotion. V is the unconverted value.
			*/
			#define _GL_INT_CONVERT(e, v) (0 * (e) + (v))
			/* Act like _GL_INT_CONVERT (E, -V) but work around a bug in IRIX 6.5 cc; s
			ee
			<http://lists.gnu.org/archive/html/bug-gnulib/2011-05/msg00406.html>. *
			/
			#define _GL_INT_NEGATE_CONVERT(e, v) (0 * (e) - (v))
	/* The extra casts in the following macros work around compiler bugs,		/* The extra casts in the following macros work around compiler bugs,
	e.g., in Cray C 5.0.3.0. */		e.g., in Cray C 5.0.3.0. */
	/* True if the arithmetic type T is an integer type. bool counts as		/* True if the arithmetic type T is an integer type. bool counts as
	an integer. */		an integer. */
	# define TYPE_IS_INTEGER(t) ((t) 1.5 == 1)		#define TYPE_IS_INTEGER(t) ((t) 1.5 == 1)
	/* True if negative values of the signed integer type T use two's		/* True if negative values of the signed integer type T use two's
	complement, ones' complement, or signed magnitude representation,		complement, ones' complement, or signed magnitude representation,
	respectively. Much GNU code assumes two's complement, but some		respectively. Much GNU code assumes two's complement, but some
	people like to be portable to all possible C hosts. */		people like to be portable to all possible C hosts. */
	# define TYPE_TWOS_COMPLEMENT(t) ((t) ~ (t) 0 == (t) -1)		#define TYPE_TWOS_COMPLEMENT(t) ((t) ~ (t) 0 == (t) -1)
	# define TYPE_ONES_COMPLEMENT(t) ((t) ~ (t) 0 == 0)		#define TYPE_ONES_COMPLEMENT(t) ((t) ~ (t) 0 == 0)
	# define TYPE_SIGNED_MAGNITUDE(t) ((t) ~ (t) 0 < (t) -1)		#define TYPE_SIGNED_MAGNITUDE(t) ((t) ~ (t) 0 < (t) -1)
			/* True if the signed integer expression E uses two's complement. */
			#define _GL_INT_TWOS_COMPLEMENT(e) (~ _GL_INT_CONVERT (e, 0) == -1)
	/* True if the arithmetic type T is signed. */		/* True if the arithmetic type T is signed. */
	# define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))		#define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
	/* The maximum and minimum values for the integer type T. These		/* Return 1 if the integer expression E, after integer promotion, has
			a signed type. */
			#define _GL_INT_SIGNED(e) (_GL_INT_NEGATE_CONVERT (e, 1) < 0)
			/* Minimum and maximum values for integer types and expressions. These
	macros have undefined behavior if T is signed and has padding bits.		macros have undefined behavior if T is signed and has padding bits.
	If this is a problem for you, please let us know how to fix it for		If this is a problem for you, please let us know how to fix it for
	your host. */		your host. */
	# define TYPE_MINIMUM(t) \
	((t) (! TYPE_SIGNED (t) \		/* The maximum and minimum values for the integer type T. */
	? (t) 0 \		#define TYPE_MINIMUM(t) \
	: TYPE_SIGNED_MAGNITUDE (t) \		((t) (! TYPE_SIGNED (t) \
	? ~ (t) 0 \		? (t) 0 \
	: ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1)))		: TYPE_SIGNED_MAGNITUDE (t) \
	# define TYPE_MAXIMUM(t) \		? ~ (t) 0 \
	((t) (! TYPE_SIGNED (t) \		: ~ TYPE_MAXIMUM (t)))
	? (t) -1 \		#define TYPE_MAXIMUM(t) \
	: ~ (~ (t) 0 << (sizeof (t) * CHAR_BIT - 1))))		((t) (! TYPE_SIGNED (t) \
			? (t) -1 \
	/* Return zero if T can be determined to be an unsigned type.		: ((((t) 1 << (sizeof (t) * CHAR_BIT - 2)) - 1) * 2 + 1)))
	Otherwise, return 1.
	When compiling with GCC, INT_STRLEN_BOUND uses this macro to obtain a		/* The maximum and minimum values for the type of the expression E,
	tighter bound. Otherwise, it overestimates the true bound by one byte		after integer promotion. E should not have side effects. */
	when applied to unsigned types of size 2, 4, 16, ... bytes.		#define _GL_INT_MINIMUM(e) \
	The symbol signed_type_or_expr__ is private to this header file. */		(_GL_INT_SIGNED (e) \
	# if __GNUC__ >= 2		? - _GL_INT_TWOS_COMPLEMENT (e) - _GL_SIGNED_INT_MAXIMUM (e) \
	# define signed_type_or_expr__(t) TYPE_SIGNED (__typeof__ (t))		: _GL_INT_CONVERT (e, 0))
	# else		#define _GL_INT_MAXIMUM(e) \
	# define signed_type_or_expr__(t) 1		(_GL_INT_SIGNED (e) \
	# endif		? _GL_SIGNED_INT_MAXIMUM (e) \
			: _GL_INT_NEGATE_CONVERT (e, 1))
			#define _GL_SIGNED_INT_MAXIMUM(e) \
			(((_GL_INT_CONVERT (e, 1) << (sizeof ((e) + 0) * CHAR_BIT - 2)) - 1) * 2
			+ 1)
			/* Return 1 if the __typeof__ keyword works. This could be done by
			'configure', but for now it's easier to do it by hand. */
			#if (2 <= __GNUC__ || defined __IBM__TYPEOF__ \
			|| (0x5110 <= __SUNPRO_C && !__STDC__))
			# define _GL_HAVE___TYPEOF__ 1
			#else
			# define _GL_HAVE___TYPEOF__ 0
			#endif
			/* Return 1 if the integer type or expression T might be signed. Return 0
			if it is definitely unsigned. This macro does not evaluate its argument
			,
			and expands to an integer constant expression. */
			#if _GL_HAVE___TYPEOF__
			# define _GL_SIGNED_TYPE_OR_EXPR(t) TYPE_SIGNED (__typeof__ (t))
			#else
			# define _GL_SIGNED_TYPE_OR_EXPR(t) 1
			#endif
			/* Bound on length of the string representing an unsigned integer
			value representable in B bits. log10 (2.0) < 146/485. The
			smallest value of B where this bound is not tight is 2621. */
			#define INT_BITS_STRLEN_BOUND(b) (((b) * 146 + 484) / 485)
	/* Bound on length of the string representing an integer type or expression T.		/* Bound on length of the string representing an integer type or expression T.
	Subtract 1 for the sign bit if T is signed; log10 (2.0) < 146/485;		Subtract 1 for the sign bit if T is signed, and then add 1 more for
	add 1 for integer division truncation; add 1 more for a minus sign		a minus sign if needed.
	if needed. */
	# define INT_STRLEN_BOUND(t) \		Because _GL_SIGNED_TYPE_OR_EXPR sometimes returns 0 when its argument is
	((sizeof (t) * CHAR_BIT - signed_type_or_expr__ (t)) * 146 / 485 \		signed, this macro may overestimate the true bound by one byte when
	+ signed_type_or_expr__ (t) + 1)		applied to unsigned types of size 2, 4, 16, ... bytes. */
			#define INT_STRLEN_BOUND(t) \
			(INT_BITS_STRLEN_BOUND (sizeof (t) * CHAR_BIT \
			- _GL_SIGNED_TYPE_OR_EXPR (t)) \
			+ _GL_SIGNED_TYPE_OR_EXPR (t))
	/* Bound on buffer size needed to represent an integer type or expression T ,		/* Bound on buffer size needed to represent an integer type or expression T ,
	including the terminating null. */		including the terminating null. */
	# define INT_BUFSIZE_BOUND(t) (INT_STRLEN_BOUND (t) + 1)		#define INT_BUFSIZE_BOUND(t) (INT_STRLEN_BOUND (t) + 1)
			/* Range overflow checks.
			The INT_<op>_RANGE_OVERFLOW macros return 1 if the corresponding C
			operators might not yield numerically correct answers due to
			arithmetic overflow. They do not rely on undefined or
			implementation-defined behavior. Their implementations are simple
			and straightforward, but they are a bit harder to use than the
			INT_<op>_OVERFLOW macros described below.
			Example usage:
			long int i = ...;
			long int j = ...;
			if (INT_MULTIPLY_RANGE_OVERFLOW (i, j, LONG_MIN, LONG_MAX))
			printf ("multiply would overflow");
			else
			printf ("product is %ld", i * j);
			Restrictions on *_RANGE_OVERFLOW macros:
			These macros do not check for all possible numerical problems or
			undefined or unspecified behavior: they do not check for division
			by zero, for bad shift counts, or for shifting negative numbers.
			These macros may evaluate their arguments zero or multiple times,
			so the arguments should not have side effects. The arithmetic
			arguments (including the MIN and MAX arguments) must be of the same
			integer type after the usual arithmetic conversions, and the type
			must have minimum value MIN and maximum MAX. Unsigned types should
			use a zero MIN of the proper type.
			These macros are tuned for constant MIN and MAX. For commutative
			operations such as A + B, they are also tuned for constant B. */
			/* Return 1 if A + B would overflow in [MIN,MAX] arithmetic.
			See above for restrictions. */
			#define INT_ADD_RANGE_OVERFLOW(a, b, min, max) \
			((b) < 0 \
			? (a) < (min) - (b) \
			: (max) - (b) < (a))
			/* Return 1 if A - B would overflow in [MIN,MAX] arithmetic.
			See above for restrictions. */
			#define INT_SUBTRACT_RANGE_OVERFLOW(a, b, min, max) \
			((b) < 0 \
			? (max) + (b) < (a) \
			: (a) < (min) + (b))
			/* Return 1 if - A would overflow in [MIN,MAX] arithmetic.
			See above for restrictions. */
			#define INT_NEGATE_RANGE_OVERFLOW(a, min, max) \
			((min) < 0 \
			? (a) < - (max) \
			: 0 < (a))
			/* Return 1 if A * B would overflow in [MIN,MAX] arithmetic.
			See above for restrictions. Avoid && and || as they tickle
			bugs in Sun C 5.11 2010/08/13 and other compilers; see
			<http://lists.gnu.org/archive/html/bug-gnulib/2011-05/msg00401.html>. *
			/
			#define INT_MULTIPLY_RANGE_OVERFLOW(a, b, min, max) \
			((b) < 0 \
			? ((a) < 0 \
			? (a) < (max) / (b) \
			: (b) == -1 \
			? 0 \
			: (min) / (b) < (a)) \
			: (b) == 0 \
			? 0 \
			: ((a) < 0 \
			? (a) < (min) / (b) \
			: (max) / (b) < (a)))
			/* Return 1 if A / B would overflow in [MIN,MAX] arithmetic.
			See above for restrictions. Do not check for division by zero. */
			#define INT_DIVIDE_RANGE_OVERFLOW(a, b, min, max) \
			((min) < 0 && (b) == -1 && (a) < - (max))
			/* Return 1 if A % B would overflow in [MIN,MAX] arithmetic.
			See above for restrictions. Do not check for division by zero.
			Mathematically, % should never overflow, but on x86-like hosts
			INT_MIN % -1 traps, and the C standard permits this, so treat this
			as an overflow too. */
			#define INT_REMAINDER_RANGE_OVERFLOW(a, b, min, max) \
			INT_DIVIDE_RANGE_OVERFLOW (a, b, min, max)
			/* Return 1 if A << B would overflow in [MIN,MAX] arithmetic.
			See above for restrictions. Here, MIN and MAX are for A only, and B nee
			d
			not be of the same type as the other arguments. The C standard says tha
			t
			behavior is undefined for shifts unless 0 <= B < wordwidth, and that whe
			n
			A is negative then A << B has undefined behavior and A >> B has
			implementation-defined behavior, but do not check these other
			restrictions. */
			#define INT_LEFT_SHIFT_RANGE_OVERFLOW(a, b, min, max) \
			((a) < 0 \
			? (a) < (min) >> (b) \
			: (max) >> (b) < (a))
			/* The _GL*_OVERFLOW macros have the same restrictions as the
			*_RANGE_OVERFLOW macros, except that they do not assume that operands
			(e.g., A and B) have the same type as MIN and MAX. Instead, they assume
			that the result (e.g., A + B) has that type. */
			#define _GL_ADD_OVERFLOW(a, b, min, max) \
			((min) < 0 ? INT_ADD_RANGE_OVERFLOW (a, b, min, max) \
			: (a) < 0 ? (b) <= (a) + (b) \
			: (b) < 0 ? (a) <= (a) + (b) \
			: (a) + (b) < (b))
			#define _GL_SUBTRACT_OVERFLOW(a, b, min, max) \
			((min) < 0 ? INT_SUBTRACT_RANGE_OVERFLOW (a, b, min, max) \
			: (a) < 0 ? 1 \
			: (b) < 0 ? (a) - (b) <= (a) \
			: (a) < (b))
			#define _GL_MULTIPLY_OVERFLOW(a, b, min, max) \
			(((min) == 0 && (((a) < 0 && 0 < (b)) || ((b) < 0 && 0 < (a)))) \
			|| INT_MULTIPLY_RANGE_OVERFLOW (a, b, min, max))
			#define _GL_DIVIDE_OVERFLOW(a, b, min, max) \
			((min) < 0 ? (b) == _GL_INT_NEGATE_CONVERT (min, 1) && (a) < - (max) \
			: (a) < 0 ? (b) <= (a) + (b) - 1 \
			: (b) < 0 && (a) + (b) <= (a))
			#define _GL_REMAINDER_OVERFLOW(a, b, min, max) \
			((min) < 0 ? (b) == _GL_INT_NEGATE_CONVERT (min, 1) && (a) < - (max) \
			: (a) < 0 ? (a) % (b) != ((max) - (b) + 1) % (b) \
			: (b) < 0 && ! _GL_UNSIGNED_NEG_MULTIPLE (a, b, max))
			/* Return a nonzero value if A is a mathematical multiple of B, where
			A is unsigned, B is negative, and MAX is the maximum value of A's
			type. A's type must be the same as (A % B)'s type. Normally (A %
			-B == 0) suffices, but things get tricky if -B would overflow. */
			#define _GL_UNSIGNED_NEG_MULTIPLE(a, b, max) \
			(((b) < -_GL_SIGNED_INT_MAXIMUM (b) \
			? (_GL_SIGNED_INT_MAXIMUM (b) == (max) \
			? (a) \
			: (a) % (_GL_INT_CONVERT (a, _GL_SIGNED_INT_MAXIMUM (b)) + 1)) \
			: (a) % - (b)) \
			== 0)
			/* Integer overflow checks.
			The INT_<op>_OVERFLOW macros return 1 if the corresponding C operators
			might not yield numerically correct answers due to arithmetic overflow.
			They work correctly on all known practical hosts, and do not rely
			on undefined behavior due to signed arithmetic overflow.
			Example usage:
			long int i = ...;
			long int j = ...;
			if (INT_MULTIPLY_OVERFLOW (i, j))
			printf ("multiply would overflow");
			else
			printf ("product is %ld", i * j);
			These macros do not check for all possible numerical problems or
			undefined or unspecified behavior: they do not check for division
			by zero, for bad shift counts, or for shifting negative numbers.
			These macros may evaluate their arguments zero or multiple times, so the
			arguments should not have side effects.
			These macros are tuned for their last argument being a constant.
			Return 1 if the integer expressions A * B, A - B, -A, A * B, A / B,
			A % B, and A << B would overflow, respectively. */
			#define INT_ADD_OVERFLOW(a, b) \
			_GL_BINARY_OP_OVERFLOW (a, b, _GL_ADD_OVERFLOW)
			#define INT_SUBTRACT_OVERFLOW(a, b) \
			_GL_BINARY_OP_OVERFLOW (a, b, _GL_SUBTRACT_OVERFLOW)
			#define INT_NEGATE_OVERFLOW(a) \
			INT_NEGATE_RANGE_OVERFLOW (a, _GL_INT_MINIMUM (a), _GL_INT_MAXIMUM (a))
			#define INT_MULTIPLY_OVERFLOW(a, b) \
			_GL_BINARY_OP_OVERFLOW (a, b, _GL_MULTIPLY_OVERFLOW)
			#define INT_DIVIDE_OVERFLOW(a, b) \
			_GL_BINARY_OP_OVERFLOW (a, b, _GL_DIVIDE_OVERFLOW)
			#define INT_REMAINDER_OVERFLOW(a, b) \
			_GL_BINARY_OP_OVERFLOW (a, b, _GL_REMAINDER_OVERFLOW)
			#define INT_LEFT_SHIFT_OVERFLOW(a, b) \
			INT_LEFT_SHIFT_RANGE_OVERFLOW (a, b, \
			_GL_INT_MINIMUM (a), _GL_INT_MAXIMUM (a))
			/* Return 1 if the expression A <op> B would overflow,
			where OP_RESULT_OVERFLOW (A, B, MIN, MAX) does the actual test,
			assuming MIN and MAX are the minimum and maximum for the result type.
			Arguments should be free of side effects. */
			#define _GL_BINARY_OP_OVERFLOW(a, b, op_result_overflow) \
			op_result_overflow (a, b, \
			_GL_INT_MINIMUM (0 * (b) + (a)), \
			_GL_INT_MAXIMUM (0 * (b) + (a)))
	#endif /* GL_INTPROPS_H */		#endif /* _GL_INTPROPS_H */
End of changes. 11 change blocks.
	40 lines changed or deleted		281 lines changed or added
This html diff was produced by rfcdiff 1.41. The latest version is available from http://tools.ietf.org/tools/rfcdiff/