/* intprops.h -- properties of integer types
- Copyright (C) 2001-2005, 2009-2015 Free Software Foundation, Inc.
+ Copyright (C) 2001-2016 Free Software Foundation, Inc.
- 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
- the Free Software Foundation; either version 3 of the License, or
+ 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 the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
#define _GL_INTPROPS_H
#include <limits.h>
+#include <verify.h>
/* Return a value with the common real type of E and V and the value of V. */
#define _GL_INT_CONVERT(e, v) (0 * (e) + (v))
an integer. */
#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)
-
-/* 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 real type T is signed. */
#define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
#define EXPR_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.
- If this is a problem for you, please let us know how to fix it for
- your host. */
+/* Minimum and maximum values for integer types and expressions. */
/* 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_MINIMUM(t) ((t) ~ TYPE_MAXIMUM (t))
#define TYPE_MAXIMUM(t) \
((t) (! TYPE_SIGNED (t) \
? (t) -1 \
after integer promotion. E should not have side effects. */
#define _GL_INT_MINIMUM(e) \
(EXPR_SIGNED (e) \
- ? - _GL_INT_TWOS_COMPLEMENT (e) - _GL_SIGNED_INT_MAXIMUM (e) \
+ ? ~ _GL_SIGNED_INT_MAXIMUM (e) \
: _GL_INT_CONVERT (e, 0))
#define _GL_INT_MAXIMUM(e) \
(EXPR_SIGNED (e) \
#define _GL_SIGNED_INT_MAXIMUM(e) \
(((_GL_INT_CONVERT (e, 1) << (sizeof ((e) + 0) * CHAR_BIT - 2)) - 1) * 2 + 1)
+/* This include file assumes that signed types are two's complement without
+ padding bits; the above macros have undefined behavior otherwise.
+ If this is a problem for you, please let us know how to fix it for your host.
+ As a sanity check, test the assumption for some signed types that
+ <limits.h> bounds. */
+verify (TYPE_MINIMUM (signed char) == SCHAR_MIN);
+verify (TYPE_MAXIMUM (signed char) == SCHAR_MAX);
+verify (TYPE_MINIMUM (short int) == SHRT_MIN);
+verify (TYPE_MAXIMUM (short int) == SHRT_MAX);
+verify (TYPE_MINIMUM (int) == INT_MIN);
+verify (TYPE_MAXIMUM (int) == INT_MAX);
+verify (TYPE_MINIMUM (long int) == LONG_MIN);
+verify (TYPE_MAXIMUM (long int) == LONG_MAX);
+#ifdef LLONG_MAX
+verify (TYPE_MINIMUM (long long int) == LLONG_MIN);
+verify (TYPE_MAXIMUM (long long int) == LLONG_MAX);
+#endif
-/* Return 1 if the __typeof__ keyword works. This could be done by
+/* Does the __typeof__ keyword work? 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__))
? (a) < (min) >> (b) \
: (max) >> (b) < (a))
+/* True if __builtin_add_overflow (A, B, P) works when P is null. */
+#define _GL_HAS_BUILTIN_OVERFLOW_WITH_NULL (7 <= __GNUC__)
/* 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))
+#if _GL_HAS_BUILTIN_OVERFLOW_WITH_NULL
+# define _GL_ADD_OVERFLOW(a, b, min, max)
+ __builtin_add_overflow (a, b, (__typeof__ ((a) + (b)) *) 0)
+# define _GL_SUBTRACT_OVERFLOW(a, b, min, max)
+ __builtin_sub_overflow (a, b, (__typeof__ ((a) - (b)) *) 0)
+# define _GL_MULTIPLY_OVERFLOW(a, b, min, max)
+ __builtin_mul_overflow (a, b, (__typeof__ ((a) * (b)) *) 0)
+#else
+# 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))
+#endif
#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 \
_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))
+#if _GL_HAS_BUILTIN_OVERFLOW_WITH_NULL
+# define INT_NEGATE_OVERFLOW(a) INT_SUBTRACT_OVERFLOW (0, a)
+#else
+# define INT_NEGATE_OVERFLOW(a) \
+ INT_NEGATE_RANGE_OVERFLOW (a, _GL_INT_MINIMUM (a), _GL_INT_MAXIMUM (a))
+#endif
#define INT_MULTIPLY_OVERFLOW(a, b) \
_GL_BINARY_OP_OVERFLOW (a, b, _GL_MULTIPLY_OVERFLOW)
#define INT_DIVIDE_OVERFLOW(a, b) \
_GL_INT_MINIMUM (0 * (b) + (a)), \
_GL_INT_MAXIMUM (0 * (b) + (a)))
-/* Compute A + B, A - B, A * B, respectively, storing the result into *R.
+/* Store the low-order bits of A + B, A - B, A * B, respectively, into *R.
Return 1 if the result overflows. See above for restrictions. */
#define INT_ADD_WRAPV(a, b, r) \
_GL_INT_OP_WRAPV (a, b, r, +, __builtin_add_overflow, INT_ADD_OVERFLOW)
# define _GL__GENERIC_BOGUS 0
#endif
-/* Store A <op> B into *R, where OP specifies the operation.
- BUILTIN is the builtin operation, and OVERFLOW the overflow predicate.
- See above for restrictions. */
+/* Store the low-order bits of A <op> B into *R, where OP specifies
+ the operation. BUILTIN is the builtin operation, and OVERFLOW the
+ overflow predicate. Return 1 if the result overflows. See above
+ for restrictions. */
#if 5 <= __GNUC__ || __has_builtin (__builtin_add_overflow)
# define _GL_INT_OP_WRAPV(a, b, r, op, builtin, overflow) builtin (a, b, r)
#elif 201112 <= __STDC_VERSION__ && !_GL__GENERIC_BOGUS
/* Store the low-order bits of A <op> B into *R, where the operation
is given by OP. Use the unsigned type UT for calculation to avoid
overflow problems. *R's type is T, with extremal values TMIN and
- TMAX. T must be a signed integer type. */
+ TMAX. T must be a signed integer type. Return 1 if the result
+ overflows. */
#define _GL_INT_OP_CALC(a, b, r, op, overflow, ut, t, tmin, tmax) \
(sizeof ((a) op (b)) < sizeof (t) \
? _GL_INT_OP_CALC1 ((t) (a), (t) (b), r, op, overflow, ut, t, tmin, tmax) \