/* intprops.h -- properties of integer types Copyright (C) 2001, 2002, 2003, 2004, 2005 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 2, 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)