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/* intprops.h -- properties of integer types
Copyright (C) 2001-2005, 2009-2011 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
(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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
/* Written by Paul Eggert. */
#ifndef GL_INTPROPS_H
# define GL_INTPROPS_H
# include <limits.h>
/* 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 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 arithmetic type T is signed. */
# define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
/* The maximum and minimum values for the integer type T. 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 \
: ~ TYPE_MAXIMUM (t)))
# 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
/* 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.
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))
/* 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)
#endif /* GL_INTPROPS_H */
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