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