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Diffstat (limited to 'lib/intprops.h')

-rw-r--r-- | lib/intprops.h | 79 |

1 files changed, 79 insertions, 0 deletions

diff --git a/lib/intprops.h b/lib/intprops.h new file mode 100644 index 0000000..7db55e9 --- /dev/null +++ b/lib/intprops.h @@ -0,0 +1,79 @@ +/* intprops.h -- properties of integer types + + Copyright (C) 2001, 2002, 2003, 2004, 2005, + 2007 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, 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, write to the Free Software Foundation, + Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ + +/* Written by Paul Eggert. */ + +#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 \ + : ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1))) +#define TYPE_MAXIMUM(t) \ + ((t) (! TYPE_SIGNED (t) \ + ? (t) -1 \ + : ~ (~ (t) 0 << (sizeof (t) * CHAR_BIT - 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 integer type or expression T. + Subtract 1 for the sign bit if T is signed; log10 (2.0) < 146/485; + add 1 for integer division truncation; add 1 more for a minus sign + if needed. */ +#define INT_STRLEN_BOUND(t) \ + ((sizeof (t) * CHAR_BIT - signed_type_or_expr__ (t)) * 146 / 485 \ + + signed_type_or_expr__ (t) + 1) + +/* 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) |