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Diffstat (limited to 'lib/intprops.h')
| -rw-r--r-- | lib/intprops.h | 638 |
1 files changed, 0 insertions, 638 deletions
diff --git a/lib/intprops.h b/lib/intprops.h deleted file mode 100644 index 68d6daa5..00000000 --- a/lib/intprops.h +++ /dev/null @@ -1,638 +0,0 @@ -/* intprops.h -- properties of integer types - - Copyright (C) 2001-2022 Free Software Foundation, Inc. - - This program is free software: you can redistribute it and/or modify it - under the terms of the GNU Lesser General Public License as published - by the Free Software Foundation; either version 2.1 of the License, or - (at your option) any later version. - - This program is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - GNU Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public License - along with this program. If not, see <https://www.gnu.org/licenses/>. */ - - -#ifndef _GL_INTPROPS_H -#define _GL_INTPROPS_H - -#include <limits.h> - -/* Return a value with the common real type of E and V and the value of V. - Do not evaluate E. */ -#define _GL_INT_CONVERT(e, v) ((1 ? 0 : (e)) + (v)) - -/* Act like _GL_INT_CONVERT (E, -V) but work around a bug in IRIX 6.5 cc; see - <https://lists.gnu.org/r/bug-gnulib/2011-05/msg00406.html>. */ -#define _GL_INT_NEGATE_CONVERT(e, v) ((1 ? 0 : (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) - -/* True if the real type T is signed. */ -#define TYPE_SIGNED(t) (! ((t) 0 < (t) -1)) - -/* Return 1 if the real expression E, after promotion, has a - signed or floating type. Do not evaluate E. */ -#define EXPR_SIGNED(e) (_GL_INT_NEGATE_CONVERT (e, 1) < 0) - - -/* Minimum and maximum values for integer types and expressions. */ - -/* The width in bits of the integer type or expression T. - Do not evaluate T. T must not be a bit-field expression. - Padding bits are not supported; this is checked at compile-time below. */ -#define TYPE_WIDTH(t) (sizeof (t) * CHAR_BIT) - -/* The maximum and minimum values for the integer type T. */ -#define TYPE_MINIMUM(t) ((t) ~ TYPE_MAXIMUM (t)) -#define TYPE_MAXIMUM(t) \ - ((t) (! TYPE_SIGNED (t) \ - ? (t) -1 \ - : ((((t) 1 << (TYPE_WIDTH (t) - 2)) - 1) * 2 + 1))) - -/* The maximum and minimum values for the type of the expression E, - after integer promotion. E is not evaluated. */ -#define _GL_INT_MINIMUM(e) \ - (EXPR_SIGNED (e) \ - ? ~ _GL_SIGNED_INT_MAXIMUM (e) \ - : _GL_INT_CONVERT (e, 0)) -#define _GL_INT_MAXIMUM(e) \ - (EXPR_SIGNED (e) \ - ? _GL_SIGNED_INT_MAXIMUM (e) \ - : _GL_INT_NEGATE_CONVERT (e, 1)) -#define _GL_SIGNED_INT_MAXIMUM(e) \ - (((_GL_INT_CONVERT (e, 1) << (TYPE_WIDTH (+ (e)) - 2)) - 1) * 2 + 1) - -/* Work around OpenVMS incompatibility with C99. */ -#if !defined LLONG_MAX && defined __INT64_MAX -# define LLONG_MAX __INT64_MAX -# define LLONG_MIN __INT64_MIN -#endif - -/* 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. - This assumption is tested by the intprops-tests module. */ - -/* 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__ \ - || (4 <= __clang_major__) \ - || (1210 <= __IBMC__ && 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. T must not be a bit-field expression. - 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. - T must not be a bit-field expression. - - Subtract 1 for the sign bit if T is signed, and then add 1 more for - a minus sign if needed. - - Because _GL_SIGNED_TYPE_OR_EXPR sometimes returns 1 when its argument is - unsigned, 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 (TYPE_WIDTH (t) - _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. T must not be a bit-field expression. */ -#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 harder to use and may be less - efficient than the INT_<op>_WRAPV, INT_<op>_OK, and - 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. - - Because all arguments are subject to integer promotions, these - macros typically do not work on types narrower than 'int'. - - 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 - <https://lists.gnu.org/r/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 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)) - -/* True if __builtin_add_overflow (A, B, P) and __builtin_sub_overflow - (A, B, P) work when P is non-null. */ -#if defined __has_builtin -# define _GL_HAS_BUILTIN_ADD_OVERFLOW __has_builtin (__builtin_add_overflow) -/* __builtin_{add,sub}_overflow exists but is not reliable in GCC 5.x and 6.x, - see <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98269>. */ -#elif 7 <= __GNUC__ && !defined __EDG__ -# define _GL_HAS_BUILTIN_ADD_OVERFLOW 1 -#else -# define _GL_HAS_BUILTIN_ADD_OVERFLOW 0 -#endif - -/* True if __builtin_mul_overflow (A, B, P) works when P is non-null. */ -#if defined __clang_major__ && __clang_major__ < 14 -/* Work around Clang bug <https://bugs.llvm.org/show_bug.cgi?id=16404>. */ -# define _GL_HAS_BUILTIN_MUL_OVERFLOW 0 -#else -# define _GL_HAS_BUILTIN_MUL_OVERFLOW _GL_HAS_BUILTIN_ADD_OVERFLOW -#endif - -/* True if __builtin_add_overflow_p (A, B, C) works, and similarly for - __builtin_sub_overflow_p and __builtin_mul_overflow_p. */ -#ifdef __EDG__ -/* In EDG-based compilers like ICC 2021.3 and earlier, - __builtin_add_overflow_p etc. are not treated as integral constant - expressions even when all arguments are. */ -# define _GL_HAS_BUILTIN_OVERFLOW_P 0 -#elif defined __has_builtin -# define _GL_HAS_BUILTIN_OVERFLOW_P __has_builtin (__builtin_mul_overflow_p) -#else -# define _GL_HAS_BUILTIN_OVERFLOW_P (7 <= __GNUC__) -#endif - -/* 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. */ -#if _GL_HAS_BUILTIN_OVERFLOW_P -# define _GL_ADD_OVERFLOW(a, b, min, max) \ - __builtin_add_overflow_p (a, b, (__typeof__ ((a) + (b))) 0) -# define _GL_SUBTRACT_OVERFLOW(a, b, min, max) \ - __builtin_sub_overflow_p (a, b, (__typeof__ ((a) - (b))) 0) -# define _GL_MULTIPLY_OVERFLOW(a, b, min, max) \ - __builtin_mul_overflow_p (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 \ - : (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) - -/* Check for integer overflow, and report low order bits of answer. - - The INT_<op>_OVERFLOW macros return 1 if the corresponding C operators - might not yield numerically correct answers due to arithmetic overflow. - The INT_<op>_WRAPV macros compute the low-order bits of the sum, - difference, and product of two C integers, and return 1 if these - low-order bits are not numerically correct. - These macros work correctly on all known practical hosts, and do not rely - on undefined behavior due to signed arithmetic overflow. - - Example usage, assuming A and B are long int: - - if (INT_MULTIPLY_OVERFLOW (a, b)) - printf ("result would overflow\n"); - else - printf ("result is %ld (no overflow)\n", a * b); - - Example usage with WRAPV flavor: - - long int result; - bool overflow = INT_MULTIPLY_WRAPV (a, b, &result); - printf ("result is %ld (%s)\n", result, - overflow ? "after overflow" : "no overflow"); - - Restrictions on these 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 WRAPV macros are not constant expressions. They support only - +, binary -, and *. - - Because the WRAPV macros convert the result, they report overflow - in different circumstances than the OVERFLOW macros do. For - example, in the typical case with 16-bit 'short' and 32-bit 'int', - if A, B and R are all of type 'short' then INT_ADD_OVERFLOW (A, B) - returns false because the addition cannot overflow after A and B - are converted to 'int', whereas INT_ADD_WRAPV (A, B, &R) returns - true or false depending on whether the sum fits into 'short'. - - These macros are tuned for their last input 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) -#if _GL_HAS_BUILTIN_OVERFLOW_P -# 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_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 (_GL_INT_CONVERT (a, b)), \ - _GL_INT_MAXIMUM (_GL_INT_CONVERT (a, b))) - -/* 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. */ -#if _GL_HAS_BUILTIN_ADD_OVERFLOW -# define INT_ADD_WRAPV(a, b, r) __builtin_add_overflow (a, b, r) -# define INT_SUBTRACT_WRAPV(a, b, r) __builtin_sub_overflow (a, b, r) -#else -# define INT_ADD_WRAPV(a, b, r) \ - _GL_INT_OP_WRAPV (a, b, r, +, _GL_INT_ADD_RANGE_OVERFLOW) -# define INT_SUBTRACT_WRAPV(a, b, r) \ - _GL_INT_OP_WRAPV (a, b, r, -, _GL_INT_SUBTRACT_RANGE_OVERFLOW) -#endif -#if _GL_HAS_BUILTIN_MUL_OVERFLOW -# if ((9 < __GNUC__ + (3 <= __GNUC_MINOR__) \ - || (__GNUC__ == 8 && 4 <= __GNUC_MINOR__)) \ - && !defined __EDG__) -# define INT_MULTIPLY_WRAPV(a, b, r) __builtin_mul_overflow (a, b, r) -# else - /* Work around GCC bug 91450. */ -# define INT_MULTIPLY_WRAPV(a, b, r) \ - ((!_GL_SIGNED_TYPE_OR_EXPR (*(r)) && EXPR_SIGNED (a) && EXPR_SIGNED (b) \ - && _GL_INT_MULTIPLY_RANGE_OVERFLOW (a, b, 0, (__typeof__ (*(r))) -1)) \ - ? ((void) __builtin_mul_overflow (a, b, r), 1) \ - : __builtin_mul_overflow (a, b, r)) -# endif -#else -# define INT_MULTIPLY_WRAPV(a, b, r) \ - _GL_INT_OP_WRAPV (a, b, r, *, _GL_INT_MULTIPLY_RANGE_OVERFLOW) -#endif - -/* Nonzero if this compiler has GCC bug 68193 or Clang bug 25390. See: - https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68193 - https://llvm.org/bugs/show_bug.cgi?id=25390 - For now, assume all versions of GCC-like compilers generate bogus - warnings for _Generic. This matters only for compilers that - lack relevant builtins. */ -#if __GNUC__ || defined __clang__ -# define _GL__GENERIC_BOGUS 1 -#else -# define _GL__GENERIC_BOGUS 0 -#endif - -/* Store the low-order bits of A <op> B into *R, where OP specifies - the operation and OVERFLOW the overflow predicate. Return 1 if the - result overflows. See above for restrictions. */ -#if 201112 <= __STDC_VERSION__ && !_GL__GENERIC_BOGUS -# define _GL_INT_OP_WRAPV(a, b, r, op, overflow) \ - (_Generic \ - (*(r), \ - signed char: \ - _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \ - signed char, SCHAR_MIN, SCHAR_MAX), \ - unsigned char: \ - _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \ - unsigned char, 0, UCHAR_MAX), \ - short int: \ - _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \ - short int, SHRT_MIN, SHRT_MAX), \ - unsigned short int: \ - _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \ - unsigned short int, 0, USHRT_MAX), \ - int: \ - _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \ - int, INT_MIN, INT_MAX), \ - unsigned int: \ - _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \ - unsigned int, 0, UINT_MAX), \ - long int: \ - _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \ - long int, LONG_MIN, LONG_MAX), \ - unsigned long int: \ - _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \ - unsigned long int, 0, ULONG_MAX), \ - long long int: \ - _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long long int, \ - long long int, LLONG_MIN, LLONG_MAX), \ - unsigned long long int: \ - _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long long int, \ - unsigned long long int, 0, ULLONG_MAX))) -#else -/* Store the low-order bits of A <op> B into *R, where OP specifies - the operation and OVERFLOW the overflow predicate. If *R is - signed, its type is ST with bounds SMIN..SMAX; otherwise its type - is UT with bounds U..UMAX. ST and UT are narrower than int. - Return 1 if the result overflows. See above for restrictions. */ -# if _GL_HAVE___TYPEOF__ -# define _GL_INT_OP_WRAPV_SMALLISH(a,b,r,op,overflow,st,smin,smax,ut,umax) \ - (TYPE_SIGNED (__typeof__ (*(r))) \ - ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, st, smin, smax) \ - : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, ut, 0, umax)) -# else -# define _GL_INT_OP_WRAPV_SMALLISH(a,b,r,op,overflow,st,smin,smax,ut,umax) \ - (overflow (a, b, smin, smax) \ - ? (overflow (a, b, 0, umax) \ - ? (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a,b,op,unsigned,st), 1) \ - : (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a,b,op,unsigned,st)) < 0) \ - : (overflow (a, b, 0, umax) \ - ? (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a,b,op,unsigned,st)) >= 0 \ - : (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a,b,op,unsigned,st), 0))) -# endif - -# define _GL_INT_OP_WRAPV(a, b, r, op, overflow) \ - (sizeof *(r) == sizeof (signed char) \ - ? _GL_INT_OP_WRAPV_SMALLISH (a, b, r, op, overflow, \ - signed char, SCHAR_MIN, SCHAR_MAX, \ - unsigned char, UCHAR_MAX) \ - : sizeof *(r) == sizeof (short int) \ - ? _GL_INT_OP_WRAPV_SMALLISH (a, b, r, op, overflow, \ - short int, SHRT_MIN, SHRT_MAX, \ - unsigned short int, USHRT_MAX) \ - : sizeof *(r) == sizeof (int) \ - ? (EXPR_SIGNED (*(r)) \ - ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \ - int, INT_MIN, INT_MAX) \ - : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \ - unsigned int, 0, UINT_MAX)) \ - : _GL_INT_OP_WRAPV_LONGISH(a, b, r, op, overflow)) -# ifdef LLONG_MAX -# define _GL_INT_OP_WRAPV_LONGISH(a, b, r, op, overflow) \ - (sizeof *(r) == sizeof (long int) \ - ? (EXPR_SIGNED (*(r)) \ - ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \ - long int, LONG_MIN, LONG_MAX) \ - : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \ - unsigned long int, 0, ULONG_MAX)) \ - : (EXPR_SIGNED (*(r)) \ - ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long long int, \ - long long int, LLONG_MIN, LLONG_MAX) \ - : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long long int, \ - unsigned long long int, 0, ULLONG_MAX))) -# else -# define _GL_INT_OP_WRAPV_LONGISH(a, b, r, op, overflow) \ - (EXPR_SIGNED (*(r)) \ - ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \ - long int, LONG_MIN, LONG_MAX) \ - : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \ - unsigned long int, 0, ULONG_MAX)) -# endif -#endif - -/* 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 extrema TMIN and 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) \ - (overflow (a, b, tmin, tmax) \ - ? (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a, b, op, ut, t), 1) \ - : (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a, b, op, ut, t), 0)) - -/* Return the low-order bits of A <op> B, where the operation is given - by OP. Use the unsigned type UT for calculation to avoid undefined - behavior on signed integer overflow, and convert the result to type T. - UT is at least as wide as T and is no narrower than unsigned int, - T is two's complement, and there is no padding or trap representations. - Assume that converting UT to T yields the low-order bits, as is - done in all known two's-complement C compilers. E.g., see: - https://gcc.gnu.org/onlinedocs/gcc/Integers-implementation.html - - According to the C standard, converting UT to T yields an - implementation-defined result or signal for values outside T's - range. However, code that works around this theoretical problem - runs afoul of a compiler bug in Oracle Studio 12.3 x86. See: - https://lists.gnu.org/r/bug-gnulib/2017-04/msg00049.html - As the compiler bug is real, don't try to work around the - theoretical problem. */ - -#define _GL_INT_OP_WRAPV_VIA_UNSIGNED(a, b, op, ut, t) \ - ((t) ((ut) (a) op (ut) (b))) - -/* Return true if the numeric values A + B, A - B, A * B fall outside - the range TMIN..TMAX. Arguments should be integer expressions - without side effects. TMIN should be signed and nonpositive. - TMAX should be positive, and should be signed unless TMIN is zero. */ -#define _GL_INT_ADD_RANGE_OVERFLOW(a, b, tmin, tmax) \ - ((b) < 0 \ - ? (((tmin) \ - ? ((EXPR_SIGNED (_GL_INT_CONVERT (a, (tmin) - (b))) || (b) < (tmin)) \ - && (a) < (tmin) - (b)) \ - : (a) <= -1 - (b)) \ - || ((EXPR_SIGNED (a) ? 0 <= (a) : (tmax) < (a)) && (tmax) < (a) + (b))) \ - : (a) < 0 \ - ? (((tmin) \ - ? ((EXPR_SIGNED (_GL_INT_CONVERT (b, (tmin) - (a))) || (a) < (tmin)) \ - && (b) < (tmin) - (a)) \ - : (b) <= -1 - (a)) \ - || ((EXPR_SIGNED (_GL_INT_CONVERT (a, b)) || (tmax) < (b)) \ - && (tmax) < (a) + (b))) \ - : (tmax) < (b) || (tmax) - (b) < (a)) -#define _GL_INT_SUBTRACT_RANGE_OVERFLOW(a, b, tmin, tmax) \ - (((a) < 0) == ((b) < 0) \ - ? ((a) < (b) \ - ? !(tmin) || -1 - (tmin) < (b) - (a) - 1 \ - : (tmax) < (a) - (b)) \ - : (a) < 0 \ - ? ((!EXPR_SIGNED (_GL_INT_CONVERT ((a) - (tmin), b)) && (a) - (tmin) < 0) \ - || (a) - (tmin) < (b)) \ - : ((! (EXPR_SIGNED (_GL_INT_CONVERT (tmax, b)) \ - && EXPR_SIGNED (_GL_INT_CONVERT ((tmax) + (b), a))) \ - && (tmax) <= -1 - (b)) \ - || (tmax) + (b) < (a))) -#define _GL_INT_MULTIPLY_RANGE_OVERFLOW(a, b, tmin, tmax) \ - ((b) < 0 \ - ? ((a) < 0 \ - ? (EXPR_SIGNED (_GL_INT_CONVERT (tmax, b)) \ - ? (a) < (tmax) / (b) \ - : ((INT_NEGATE_OVERFLOW (b) \ - ? _GL_INT_CONVERT (b, tmax) >> (TYPE_WIDTH (+ (b)) - 1) \ - : (tmax) / -(b)) \ - <= -1 - (a))) \ - : INT_NEGATE_OVERFLOW (_GL_INT_CONVERT (b, tmin)) && (b) == -1 \ - ? (EXPR_SIGNED (a) \ - ? 0 < (a) + (tmin) \ - : 0 < (a) && -1 - (tmin) < (a) - 1) \ - : (tmin) / (b) < (a)) \ - : (b) == 0 \ - ? 0 \ - : ((a) < 0 \ - ? (INT_NEGATE_OVERFLOW (_GL_INT_CONVERT (a, tmin)) && (a) == -1 \ - ? (EXPR_SIGNED (b) ? 0 < (b) + (tmin) : -1 - (tmin) < (b) - 1) \ - : (tmin) / (a) < (b)) \ - : (tmax) / (b) < (a))) - -/* The following macros compute A + B, A - B, and A * B, respectively. - If no overflow occurs, they set *R to the result and return 1; - otherwise, they return 0 and may modify *R. - - Example usage: - - long int result; - if (INT_ADD_OK (a, b, &result)) - printf ("result is %ld\n", result); - else - printf ("overflow\n"); - - A, B, and *R should be integers; they need not be the same type, - and they need not be all signed or all unsigned. - - These macros work correctly on all known practical hosts, and do not rely - on undefined behavior due to signed arithmetic overflow. - - These macros are not constant expressions. - - These macros may evaluate their arguments zero or multiple times, so the - arguments should not have side effects. - - These macros are tuned for B being a constant. */ - -#define INT_ADD_OK(a, b, r) ! INT_ADD_WRAPV (a, b, r) -#define INT_SUBTRACT_OK(a, b, r) ! INT_SUBTRACT_WRAPV (a, b, r) -#define INT_MULTIPLY_OK(a, b, r) ! INT_MULTIPLY_WRAPV (a, b, r) - -#endif /* _GL_INTPROPS_H */ |