/* Written by Paul Eggert. */
--#ifndef GL_INTPROPS_H
--# define GL_INTPROPS_H
++#ifndef _GL_INTPROPS_H
++#define _GL_INTPROPS_H
--# include <limits.h>
++#include <limits.h>
++
++/* Return a integer value, converted to the same type as the integer
++ expression E after integer type promotion. V is the unconverted value.
++ E should not have side effects. */
++#define _GL_INT_CONVERT(e, v) ((e) - (e) + (v))
/* The extra casts in the following macros work around compiler bugs,
e.g., in Cray C 5.0.3.0. */
/* True if the arithmetic type T is an integer type. bool counts as
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
complement, ones' complement, or signed magnitude representation,
respectively. Much GNU code assumes two's complement, but some
people like to be portable to all possible C hosts. */
--# define TYPE_TWOS_COMPLEMENT(t) ((t) ~ (t) 0 == (t) -1)
--# define TYPE_ONES_COMPLEMENT(t) ((t) ~ (t) 0 == 0)
--# define TYPE_SIGNED_MAGNITUDE(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_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. */
--# define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
++#define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
++
++/* Return 1 if the integer expression E, after integer promotion, has
++ a signed type. E should not have side effects. */
++#define _GL_INT_SIGNED(e) (_GL_INT_CONVERT (e, -1) < 0)
--/* The maximum and minimum values for the integer type T. These
++
++/* Minimum and maximum values for integer types and expressions. These
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
your host. */
--# define TYPE_MINIMUM(t) \
-- ((t) (! TYPE_SIGNED (t) \
-- ? (t) 0 \
-- : TYPE_SIGNED_MAGNITUDE (t) \
-- ? ~ (t) 0 \
++
++/* The maximum and minimum values for the integer type T. */
++#define TYPE_MINIMUM(t) \
++ ((t) (! TYPE_SIGNED (t) \
++ ? (t) 0 \
++ : TYPE_SIGNED_MAGNITUDE (t) \
++ ? ~ (t) 0 \
: ~ TYPE_MAXIMUM (t)))
--# define TYPE_MAXIMUM(t) \
-- ((t) (! TYPE_SIGNED (t) \
-- ? (t) -1 \
++#define TYPE_MAXIMUM(t) \
++ ((t) (! TYPE_SIGNED (t) \
++ ? (t) -1 \
: ((((t) 1 << (sizeof (t) * CHAR_BIT - 2)) - 1) * 2 + 1)))
--/* Return zero if T can be determined to be an unsigned type.
-- Otherwise, return 1.
-- When compiling with GCC, INT_STRLEN_BOUND uses this macro to obtain a
-- tighter bound. Otherwise, it overestimates the true bound by one byte
-- when applied to unsigned types of size 2, 4, 16, ... bytes.
-- The symbol signed_type_or_expr__ is private to this header file. */
--# if __GNUC__ >= 2
--# define signed_type_or_expr__(t) TYPE_SIGNED (__typeof__ (t))
--# else
--# define signed_type_or_expr__(t) 1
--# endif
++/* The maximum and minimum values for the type of the expression E,
++ after integer promotion. E should not have side effects. */
++#define _GL_INT_MINIMUM(e) \
++ (_GL_INT_SIGNED (e) \
++ ? - _GL_INT_TWOS_COMPLEMENT (e) - _GL_SIGNED_INT_MAXIMUM (e) \
++ : _GL_INT_CONVERT (e, 0))
++#define _GL_INT_MAXIMUM(e) \
++ (_GL_INT_SIGNED (e) \
++ ? _GL_SIGNED_INT_MAXIMUM (e) \
++ : _GL_INT_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__ || 0x5110 <= __SUNPRO_C
++# 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)
++#define INT_BITS_STRLEN_BOUND(b) (((b) * 146 + 484) / 485)
/* Bound on length of the string representing an integer type or expression T.
Subtract 1 for the sign bit if T is signed, and then add 1 more for
-- a minus sign if needed. */
--# define INT_STRLEN_BOUND(t) \
-- (INT_BITS_STRLEN_BOUND (sizeof (t) * CHAR_BIT - signed_type_or_expr__ (t)) \
-- + signed_type_or_expr__ (t))
++ a minus sign if needed.
++
++ Because _GL_SIGNED_TYPE_OR_EXPR sometimes returns 0 when its argument is
++ signed, this macro may overestimate the true bound by one byte when
++ 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,
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. */
++#define INT_MULTIPLY_RANGE_OVERFLOW(a, b, min, max) \
++ ((b) < 0 \
++ ? ((a) < 0 \
++ ? (a) < (max) / (b) \
++ : (b) < -1 && (min) / (b) < (a)) \
++ : (0 < (b) \
++ && ((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 need
++ not be of the same type as the other arguments. The C standard says that
++ behavior is undefined for shifts unless 0 <= B < wordwidth, and that when
++ 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_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_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.
++
++ This macro assumes that A | B is a valid integer if both A and B are,
++ which is true of all known practical hosts. If this is a problem
++ for you, please let us know how to fix it for your host. */
++#define _GL_BINARY_OP_OVERFLOW(a, b, op_result_overflow) \
++ op_result_overflow (a, b, \
++ _GL_INT_MINIMUM ((a) | (b)), \
++ _GL_INT_MAXIMUM ((a) | (b)))
--#endif /* GL_INTPROPS_H */
++#endif /* _GL_INTPROPS_H */
HCoop / bpt / emacs.git / commitdiff