gnulib/import/intprops.h

   1 /* intprops.h -- properties of integer types
   2
   3    Copyright (C) 2001-2016 Free Software Foundation, Inc.
   4
   5    This program is free software: you can redistribute it and/or modify it
   6    under the terms of the GNU General Public License as published
   7    by the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  17
  18 /* Written by Paul Eggert.  */
  19
  20 #ifndef _GL_INTPROPS_H
  21 #define _GL_INTPROPS_H
  22
  23 #include <limits.h>
  24 #include <verify.h>
  25
  26 #ifndef __has_builtin
  27 # define __has_builtin(x) 0
  28 #endif
  29
  30 /* Return a value with the common real type of E and V and the value of V.  */
  31 #define _GL_INT_CONVERT(e, v) (0 * (e) + (v))
  32
  33 /* Act like _GL_INT_CONVERT (E, -V) but work around a bug in IRIX 6.5 cc; see
  34    <http://lists.gnu.org/archive/html/bug-gnulib/2011-05/msg00406.html>.  */
  35 #define _GL_INT_NEGATE_CONVERT(e, v) (0 * (e) - (v))
  36
  37 /* The extra casts in the following macros work around compiler bugs,
  38    e.g., in Cray C 5.0.3.0.  */
  39
  40 /* True if the arithmetic type T is an integer type.  bool counts as
  41    an integer.  */
  42 #define TYPE_IS_INTEGER(t) ((t) 1.5 == 1)
  43
  44 /* True if the real type T is signed.  */
  45 #define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
  46
  47 /* Return 1 if the real expression E, after promotion, has a
  48    signed or floating type.  */
  49 #define EXPR_SIGNED(e) (_GL_INT_NEGATE_CONVERT (e, 1) < 0)
  50
  51
  52 /* Minimum and maximum values for integer types and expressions.  */
  53
  54 /* The width in bits of the integer type or expression T.
  55    Padding bits are not supported; this is checked at compile-time below.  */
  56 #define TYPE_WIDTH(t) (sizeof (t) * CHAR_BIT)
  57
  58 /* The maximum and minimum values for the integer type T.  */
  59 #define TYPE_MINIMUM(t) ((t) ~ TYPE_MAXIMUM (t))
  60 #define TYPE_MAXIMUM(t)                                                 \
  61   ((t) (! TYPE_SIGNED (t)                                               \
  62         ? (t) -1                                                        \
  63         : ((((t) 1 << (TYPE_WIDTH (t) - 2)) - 1) * 2 + 1)))
  64
  65 /* The maximum and minimum values for the type of the expression E,
  66    after integer promotion.  E should not have side effects.  */
  67 #define _GL_INT_MINIMUM(e)                                              \
  68   (EXPR_SIGNED (e)                                                      \
  69    ? ~ _GL_SIGNED_INT_MAXIMUM (e)                                       \
  70    : _GL_INT_CONVERT (e, 0))
  71 #define _GL_INT_MAXIMUM(e)                                              \
  72   (EXPR_SIGNED (e)                                                      \
  73    ? _GL_SIGNED_INT_MAXIMUM (e)                                         \
  74    : _GL_INT_NEGATE_CONVERT (e, 1))
  75 #define _GL_SIGNED_INT_MAXIMUM(e)                                       \
  76   (((_GL_INT_CONVERT (e, 1) << (TYPE_WIDTH ((e) + 0) - 2)) - 1) * 2 + 1)
  77
  78 /* Work around OpenVMS incompatibility with C99.  */
  79 #if !defined LLONG_MAX && defined __INT64_MAX
  80 # define LLONG_MAX __INT64_MAX
  81 # define LLONG_MIN __INT64_MIN
  82 #endif
  83
  84 /* This include file assumes that signed types are two's complement without
  85    padding bits; the above macros have undefined behavior otherwise.
  86    If this is a problem for you, please let us know how to fix it for your host.
  87    As a sanity check, test the assumption for some signed types that
  88    <limits.h> bounds.  */
  89 verify (TYPE_MINIMUM (signed char) == SCHAR_MIN);
  90 verify (TYPE_MAXIMUM (signed char) == SCHAR_MAX);
  91 verify (TYPE_MINIMUM (short int) == SHRT_MIN);
  92 verify (TYPE_MAXIMUM (short int) == SHRT_MAX);
  93 verify (TYPE_MINIMUM (int) == INT_MIN);
  94 verify (TYPE_MAXIMUM (int) == INT_MAX);
  95 verify (TYPE_MINIMUM (long int) == LONG_MIN);
  96 verify (TYPE_MAXIMUM (long int) == LONG_MAX);
  97 #ifdef LLONG_MAX
  98 verify (TYPE_MINIMUM (long long int) == LLONG_MIN);
  99 verify (TYPE_MAXIMUM (long long int) == LLONG_MAX);
 100 #endif
 101 /* Similarly, sanity-check one ISO/IEC TS 18661-1:2014 macro if defined.  */
 102 #ifdef UINT_WIDTH
 103 verify (TYPE_WIDTH (unsigned int) == UINT_WIDTH);
 104 #endif
 105
 106 /* Does the __typeof__ keyword work?  This could be done by
 107    'configure', but for now it's easier to do it by hand.  */
 108 #if (2 <= __GNUC__ \
 109      || (1210 <= __IBMC__ && defined __IBM__TYPEOF__) \
 110      || (0x5110 <= __SUNPRO_C && !__STDC__))
 111 # define _GL_HAVE___TYPEOF__ 1
 112 #else
 113 # define _GL_HAVE___TYPEOF__ 0
 114 #endif
 115
 116 /* Return 1 if the integer type or expression T might be signed.  Return 0
 117    if it is definitely unsigned.  This macro does not evaluate its argument,
 118    and expands to an integer constant expression.  */
 119 #if _GL_HAVE___TYPEOF__
 120 # define _GL_SIGNED_TYPE_OR_EXPR(t) TYPE_SIGNED (__typeof__ (t))
 121 #else
 122 # define _GL_SIGNED_TYPE_OR_EXPR(t) 1
 123 #endif
 124
 125 /* Bound on length of the string representing an unsigned integer
 126    value representable in B bits.  log10 (2.0) < 146/485.  The
 127    smallest value of B where this bound is not tight is 2621.  */
 128 #define INT_BITS_STRLEN_BOUND(b) (((b) * 146 + 484) / 485)
 129
 130 /* Bound on length of the string representing an integer type or expression T.
 131    Subtract 1 for the sign bit if T is signed, and then add 1 more for
 132    a minus sign if needed.
 133
 134    Because _GL_SIGNED_TYPE_OR_EXPR sometimes returns 0 when its argument is
 135    signed, this macro may overestimate the true bound by one byte when
 136    applied to unsigned types of size 2, 4, 16, ... bytes.  */
 137 #define INT_STRLEN_BOUND(t)                                     \
 138   (INT_BITS_STRLEN_BOUND (TYPE_WIDTH (t) - _GL_SIGNED_TYPE_OR_EXPR (t)) \
 139    + _GL_SIGNED_TYPE_OR_EXPR (t))
 140
 141 /* Bound on buffer size needed to represent an integer type or expression T,
 142    including the terminating null.  */
 143 #define INT_BUFSIZE_BOUND(t) (INT_STRLEN_BOUND (t) + 1)
 144
 145
 146 /* Range overflow checks.
 147
 148    The INT_<op>_RANGE_OVERFLOW macros return 1 if the corresponding C
 149    operators might not yield numerically correct answers due to
 150    arithmetic overflow.  They do not rely on undefined or
 151    implementation-defined behavior.  Their implementations are simple
 152    and straightforward, but they are a bit harder to use than the
 153    INT_<op>_OVERFLOW macros described below.
 154
 155    Example usage:
 156
 157      long int i = ...;
 158      long int j = ...;
 159      if (INT_MULTIPLY_RANGE_OVERFLOW (i, j, LONG_MIN, LONG_MAX))
 160        printf ("multiply would overflow");
 161      else
 162        printf ("product is %ld", i * j);
 163
 164    Restrictions on *_RANGE_OVERFLOW macros:
 165
 166    These macros do not check for all possible numerical problems or
 167    undefined or unspecified behavior: they do not check for division
 168    by zero, for bad shift counts, or for shifting negative numbers.
 169
 170    These macros may evaluate their arguments zero or multiple times,
 171    so the arguments should not have side effects.  The arithmetic
 172    arguments (including the MIN and MAX arguments) must be of the same
 173    integer type after the usual arithmetic conversions, and the type
 174    must have minimum value MIN and maximum MAX.  Unsigned types should
 175    use a zero MIN of the proper type.
 176
 177    These macros are tuned for constant MIN and MAX.  For commutative
 178    operations such as A + B, they are also tuned for constant B.  */
 179
 180 /* Return 1 if A + B would overflow in [MIN,MAX] arithmetic.
 181    See above for restrictions.  */
 182 #define INT_ADD_RANGE_OVERFLOW(a, b, min, max)          \
 183   ((b) < 0                                              \
 184    ? (a) < (min) - (b)                                  \
 185    : (max) - (b) < (a))
 186
 187 /* Return 1 if A - B would overflow in [MIN,MAX] arithmetic.
 188    See above for restrictions.  */
 189 #define INT_SUBTRACT_RANGE_OVERFLOW(a, b, min, max)     \
 190   ((b) < 0                                              \
 191    ? (max) + (b) < (a)                                  \
 192    : (a) < (min) + (b))
 193
 194 /* Return 1 if - A would overflow in [MIN,MAX] arithmetic.
 195    See above for restrictions.  */
 196 #define INT_NEGATE_RANGE_OVERFLOW(a, min, max)          \
 197   ((min) < 0                                            \
 198    ? (a) < - (max)                                      \
 199    : 0 < (a))
 200
 201 /* Return 1 if A * B would overflow in [MIN,MAX] arithmetic.
 202    See above for restrictions.  Avoid && and || as they tickle
 203    bugs in Sun C 5.11 2010/08/13 and other compilers; see
 204    <http://lists.gnu.org/archive/html/bug-gnulib/2011-05/msg00401.html>.  */
 205 #define INT_MULTIPLY_RANGE_OVERFLOW(a, b, min, max)     \
 206   ((b) < 0                                              \
 207    ? ((a) < 0                                           \
 208       ? (a) < (max) / (b)                               \
 209       : (b) == -1                                       \
 210       ? 0                                               \
 211       : (min) / (b) < (a))                              \
 212    : (b) == 0                                           \
 213    ? 0                                                  \
 214    : ((a) < 0                                           \
 215       ? (a) < (min) / (b)                               \
 216       : (max) / (b) < (a)))
 217
 218 /* Return 1 if A / B would overflow in [MIN,MAX] arithmetic.
 219    See above for restrictions.  Do not check for division by zero.  */
 220 #define INT_DIVIDE_RANGE_OVERFLOW(a, b, min, max)       \
 221   ((min) < 0 && (b) == -1 && (a) < - (max))
 222
 223 /* Return 1 if A % B would overflow in [MIN,MAX] arithmetic.
 224    See above for restrictions.  Do not check for division by zero.
 225    Mathematically, % should never overflow, but on x86-like hosts
 226    INT_MIN % -1 traps, and the C standard permits this, so treat this
 227    as an overflow too.  */
 228 #define INT_REMAINDER_RANGE_OVERFLOW(a, b, min, max)    \
 229   INT_DIVIDE_RANGE_OVERFLOW (a, b, min, max)
 230
 231 /* Return 1 if A << B would overflow in [MIN,MAX] arithmetic.
 232    See above for restrictions.  Here, MIN and MAX are for A only, and B need
 233    not be of the same type as the other arguments.  The C standard says that
 234    behavior is undefined for shifts unless 0 <= B < wordwidth, and that when
 235    A is negative then A << B has undefined behavior and A >> B has
 236    implementation-defined behavior, but do not check these other
 237    restrictions.  */
 238 #define INT_LEFT_SHIFT_RANGE_OVERFLOW(a, b, min, max)   \
 239   ((a) < 0                                              \
 240    ? (a) < (min) >> (b)                                 \
 241    : (max) >> (b) < (a))
 242
 243 /* True if __builtin_add_overflow (A, B, P) works when P is non-null.  */
 244 #define _GL_HAS_BUILTIN_OVERFLOW \
 245   (5 <= __GNUC__ || __has_builtin (__builtin_add_overflow))
 246
 247 /* True if __builtin_add_overflow_p (A, B, C) works.  */
 248 #define _GL_HAS_BUILTIN_OVERFLOW_P \
 249   (7 <= __GNUC__ || __has_builtin (__builtin_add_overflow_p))
 250
 251 /* The _GL*_OVERFLOW macros have the same restrictions as the
 252    *_RANGE_OVERFLOW macros, except that they do not assume that operands
 253    (e.g., A and B) have the same type as MIN and MAX.  Instead, they assume
 254    that the result (e.g., A + B) has that type.  */
 255 #if _GL_HAS_BUILTIN_OVERFLOW_P
 256 # define _GL_ADD_OVERFLOW(a, b, min, max)                               \
 257    __builtin_add_overflow_p (a, b, (__typeof__ ((a) + (b))) 0)
 258 # define _GL_SUBTRACT_OVERFLOW(a, b, min, max)                          \
 259    __builtin_sub_overflow_p (a, b, (__typeof__ ((a) - (b))) 0)
 260 # define _GL_MULTIPLY_OVERFLOW(a, b, min, max)                          \
 261    __builtin_mul_overflow_p (a, b, (__typeof__ ((a) * (b))) 0)
 262 #else
 263 # define _GL_ADD_OVERFLOW(a, b, min, max)                                \
 264    ((min) < 0 ? INT_ADD_RANGE_OVERFLOW (a, b, min, max)                  \
 265     : (a) < 0 ? (b) <= (a) + (b)                                         \
 266     : (b) < 0 ? (a) <= (a) + (b)                                         \
 267     : (a) + (b) < (b))
 268 # define _GL_SUBTRACT_OVERFLOW(a, b, min, max)                           \
 269    ((min) < 0 ? INT_SUBTRACT_RANGE_OVERFLOW (a, b, min, max)             \
 270     : (a) < 0 ? 1                                                        \
 271     : (b) < 0 ? (a) - (b) <= (a)                                         \
 272     : (a) < (b))
 273 # define _GL_MULTIPLY_OVERFLOW(a, b, min, max)                           \
 274    (((min) == 0 && (((a) < 0 && 0 < (b)) || ((b) < 0 && 0 < (a))))       \
 275     || INT_MULTIPLY_RANGE_OVERFLOW (a, b, min, max))
 276 #endif
 277 #define _GL_DIVIDE_OVERFLOW(a, b, min, max)                             \
 278   ((min) < 0 ? (b) == _GL_INT_NEGATE_CONVERT (min, 1) && (a) < - (max)  \
 279    : (a) < 0 ? (b) <= (a) + (b) - 1                                     \
 280    : (b) < 0 && (a) + (b) <= (a))
 281 #define _GL_REMAINDER_OVERFLOW(a, b, min, max)                          \
 282   ((min) < 0 ? (b) == _GL_INT_NEGATE_CONVERT (min, 1) && (a) < - (max)  \
 283    : (a) < 0 ? (a) % (b) != ((max) - (b) + 1) % (b)                     \
 284    : (b) < 0 && ! _GL_UNSIGNED_NEG_MULTIPLE (a, b, max))
 285
 286 /* Return a nonzero value if A is a mathematical multiple of B, where
 287    A is unsigned, B is negative, and MAX is the maximum value of A's
 288    type.  A's type must be the same as (A % B)'s type.  Normally (A %
 289    -B == 0) suffices, but things get tricky if -B would overflow.  */
 290 #define _GL_UNSIGNED_NEG_MULTIPLE(a, b, max)                            \
 291   (((b) < -_GL_SIGNED_INT_MAXIMUM (b)                                   \
 292     ? (_GL_SIGNED_INT_MAXIMUM (b) == (max)                              \
 293        ? (a)                                                            \
 294        : (a) % (_GL_INT_CONVERT (a, _GL_SIGNED_INT_MAXIMUM (b)) + 1))   \
 295     : (a) % - (b))                                                      \
 296    == 0)
 297
 298 /* Check for integer overflow, and report low order bits of answer.
 299
 300    The INT_<op>_OVERFLOW macros return 1 if the corresponding C operators
 301    might not yield numerically correct answers due to arithmetic overflow.
 302    The INT_<op>_WRAPV macros also store the low-order bits of the answer.
 303    These macros work correctly on all known practical hosts, and do not rely
 304    on undefined behavior due to signed arithmetic overflow.
 305
 306    Example usage, assuming A and B are long int:
 307
 308      if (INT_MULTIPLY_OVERFLOW (a, b))
 309        printf ("result would overflow\n");
 310      else
 311        printf ("result is %ld (no overflow)\n", a * b);
 312
 313    Example usage with WRAPV flavor:
 314
 315      long int result;
 316      bool overflow = INT_MULTIPLY_WRAPV (a, b, &result);
 317      printf ("result is %ld (%s)\n", result,
 318              overflow ? "after overflow" : "no overflow");
 319
 320    Restrictions on these macros:
 321
 322    These macros do not check for all possible numerical problems or
 323    undefined or unspecified behavior: they do not check for division
 324    by zero, for bad shift counts, or for shifting negative numbers.
 325
 326    These macros may evaluate their arguments zero or multiple times, so the
 327    arguments should not have side effects.
 328
 329    The WRAPV macros are not constant expressions.  They support only
 330    +, binary -, and *.  The result type must be signed.
 331
 332    These macros are tuned for their last argument being a constant.
 333
 334    Return 1 if the integer expressions A * B, A - B, -A, A * B, A / B,
 335    A % B, and A << B would overflow, respectively.  */
 336
 337 #define INT_ADD_OVERFLOW(a, b) \
 338   _GL_BINARY_OP_OVERFLOW (a, b, _GL_ADD_OVERFLOW)
 339 #define INT_SUBTRACT_OVERFLOW(a, b) \
 340   _GL_BINARY_OP_OVERFLOW (a, b, _GL_SUBTRACT_OVERFLOW)
 341 #if _GL_HAS_BUILTIN_OVERFLOW_P
 342 # define INT_NEGATE_OVERFLOW(a) INT_SUBTRACT_OVERFLOW (0, a)
 343 #else
 344 # define INT_NEGATE_OVERFLOW(a) \
 345    INT_NEGATE_RANGE_OVERFLOW (a, _GL_INT_MINIMUM (a), _GL_INT_MAXIMUM (a))
 346 #endif
 347 #define INT_MULTIPLY_OVERFLOW(a, b) \
 348   _GL_BINARY_OP_OVERFLOW (a, b, _GL_MULTIPLY_OVERFLOW)
 349 #define INT_DIVIDE_OVERFLOW(a, b) \
 350   _GL_BINARY_OP_OVERFLOW (a, b, _GL_DIVIDE_OVERFLOW)
 351 #define INT_REMAINDER_OVERFLOW(a, b) \
 352   _GL_BINARY_OP_OVERFLOW (a, b, _GL_REMAINDER_OVERFLOW)
 353 #define INT_LEFT_SHIFT_OVERFLOW(a, b) \
 354   INT_LEFT_SHIFT_RANGE_OVERFLOW (a, b, \
 355                                  _GL_INT_MINIMUM (a), _GL_INT_MAXIMUM (a))
 356
 357 /* Return 1 if the expression A <op> B would overflow,
 358    where OP_RESULT_OVERFLOW (A, B, MIN, MAX) does the actual test,
 359    assuming MIN and MAX are the minimum and maximum for the result type.
 360    Arguments should be free of side effects.  */
 361 #define _GL_BINARY_OP_OVERFLOW(a, b, op_result_overflow)        \
 362   op_result_overflow (a, b,                                     \
 363                       _GL_INT_MINIMUM (0 * (b) + (a)),          \
 364                       _GL_INT_MAXIMUM (0 * (b) + (a)))
 365
 366 /* Store the low-order bits of A + B, A - B, A * B, respectively, into *R.
 367    Return 1 if the result overflows.  See above for restrictions.  */
 368 #define INT_ADD_WRAPV(a, b, r) \
 369   _GL_INT_OP_WRAPV (a, b, r, +, __builtin_add_overflow, INT_ADD_OVERFLOW)
 370 #define INT_SUBTRACT_WRAPV(a, b, r) \
 371   _GL_INT_OP_WRAPV (a, b, r, -, __builtin_sub_overflow, INT_SUBTRACT_OVERFLOW)
 372 #define INT_MULTIPLY_WRAPV(a, b, r) \
 373   _GL_INT_OP_WRAPV (a, b, r, *, __builtin_mul_overflow, INT_MULTIPLY_OVERFLOW)
 374
 375 /* Nonzero if this compiler has GCC bug 68193 or Clang bug 25390.  See:
 376    https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68193
 377    https://llvm.org/bugs/show_bug.cgi?id=25390
 378    For now, assume all versions of GCC-like compilers generate bogus
 379    warnings for _Generic.  This matters only for older compilers that
 380    lack __builtin_add_overflow.  */
 381 #if __GNUC__
 382 # define _GL__GENERIC_BOGUS 1
 383 #else
 384 # define _GL__GENERIC_BOGUS 0
 385 #endif
 386
 387 /* Store the low-order bits of A <op> B into *R, where OP specifies
 388    the operation.  BUILTIN is the builtin operation, and OVERFLOW the
 389    overflow predicate.  Return 1 if the result overflows.  See above
 390    for restrictions.  */
 391 #if _GL_HAS_BUILTIN_OVERFLOW
 392 # define _GL_INT_OP_WRAPV(a, b, r, op, builtin, overflow) builtin (a, b, r)
 393 #elif 201112 <= __STDC_VERSION__ && !_GL__GENERIC_BOGUS
 394 # define _GL_INT_OP_WRAPV(a, b, r, op, builtin, overflow) \
 395    (_Generic \
 396     (*(r), \
 397      signed char: \
 398        _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned char, \
 399                         signed char, SCHAR_MIN, SCHAR_MAX), \
 400      short int: \
 401        _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned short int, \
 402                         short int, SHRT_MIN, SHRT_MAX), \
 403      int: \
 404        _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
 405                         int, INT_MIN, INT_MAX), \
 406      long int: \
 407        _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \
 408                         long int, LONG_MIN, LONG_MAX), \
 409      long long int: \
 410        _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long long int, \
 411                         long long int, LLONG_MIN, LLONG_MAX)))
 412 #else
 413 # define _GL_INT_OP_WRAPV(a, b, r, op, builtin, overflow) \
 414    (sizeof *(r) == sizeof (signed char) \
 415     ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned char, \
 416                        signed char, SCHAR_MIN, SCHAR_MAX) \
 417     : sizeof *(r) == sizeof (short int) \
 418     ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned short int, \
 419                        short int, SHRT_MIN, SHRT_MAX) \
 420     : sizeof *(r) == sizeof (int) \
 421     ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned int, \
 422                        int, INT_MIN, INT_MAX) \
 423     : _GL_INT_OP_WRAPV_LONGISH(a, b, r, op, overflow))
 424 # ifdef LLONG_MAX
 425 #  define _GL_INT_OP_WRAPV_LONGISH(a, b, r, op, overflow) \
 426     (sizeof *(r) == sizeof (long int) \
 427      ? _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \
 428                         long int, LONG_MIN, LONG_MAX) \
 429      : _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long long int, \
 430                         long long int, LLONG_MIN, LLONG_MAX))
 431 # else
 432 #  define _GL_INT_OP_WRAPV_LONGISH(a, b, r, op, overflow) \
 433     _GL_INT_OP_CALC (a, b, r, op, overflow, unsigned long int, \
 434                      long int, LONG_MIN, LONG_MAX)
 435 # endif
 436 #endif
 437
 438 /* Store the low-order bits of A <op> B into *R, where the operation
 439    is given by OP.  Use the unsigned type UT for calculation to avoid
 440    overflow problems.  *R's type is T, with extremal values TMIN and
 441    TMAX.  T must be a signed integer type.  Return 1 if the result
 442    overflows.  */
 443 #define _GL_INT_OP_CALC(a, b, r, op, overflow, ut, t, tmin, tmax) \
 444   (sizeof ((a) op (b)) < sizeof (t) \
 445    ? _GL_INT_OP_CALC1 ((t) (a), (t) (b), r, op, overflow, ut, t, tmin, tmax) \
 446    : _GL_INT_OP_CALC1 (a, b, r, op, overflow, ut, t, tmin, tmax))
 447 #define _GL_INT_OP_CALC1(a, b, r, op, overflow, ut, t, tmin, tmax) \
 448   ((overflow (a, b) \
 449     || (EXPR_SIGNED ((a) op (b)) && ((a) op (b)) < (tmin)) \
 450     || (tmax) < ((a) op (b))) \
 451    ? (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a, b, op, ut, t, tmin, tmax), 1) \
 452    : (*(r) = _GL_INT_OP_WRAPV_VIA_UNSIGNED (a, b, op, ut, t, tmin, tmax), 0))
 453
 454 /* Return A <op> B, where the operation is given by OP.  Use the
 455    unsigned type UT for calculation to avoid overflow problems.
 456    Convert the result to type T without overflow by subtracting TMIN
 457    from large values before converting, and adding it afterwards.
 458    Compilers can optimize all the operations except OP.  */
 459 #define _GL_INT_OP_WRAPV_VIA_UNSIGNED(a, b, op, ut, t, tmin, tmax) \
 460   (((ut) (a) op (ut) (b)) <= (tmax) \
 461    ? (t) ((ut) (a) op (ut) (b)) \
 462    : ((t) (((ut) (a) op (ut) (b)) - (tmin)) + (tmin)))
 463
 464 #endif /* _GL_INTPROPS_H */