1/* intprops.h -- properties of integer types 2 3 Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc. 4 5 This program is free software; you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by 7 the Free Software Foundation; either version 2, or (at your option) 8 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, write to the Free Software Foundation, 17 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ 18 19/* Written by Paul Eggert. */ 20 21#include <limits.h> 22 23/* The extra casts in the following macros work around compiler bugs, 24 e.g., in Cray C 5.0.3.0. */ 25 26/* True if the arithmetic type T is an integer type. bool counts as 27 an integer. */ 28#define TYPE_IS_INTEGER(t) ((t) 1.5 == 1) 29 30/* True if negative values of the signed integer type T use two's 31 complement, ones' complement, or signed magnitude representation, 32 respectively. Much GNU code assumes two's complement, but some 33 people like to be portable to all possible C hosts. */ 34#define TYPE_TWOS_COMPLEMENT(t) ((t) ~ (t) 0 == (t) -1) 35#define TYPE_ONES_COMPLEMENT(t) ((t) ~ (t) 0 == 0) 36#define TYPE_SIGNED_MAGNITUDE(t) ((t) ~ (t) 0 < (t) -1) 37 38/* True if the arithmetic type T is signed. */ 39#define TYPE_SIGNED(t) (! ((t) 0 < (t) -1)) 40 41/* The maximum and minimum values for the integer type T. These 42 macros have undefined behavior if T is signed and has padding bits. 43 If this is a problem for you, please let us know how to fix it for 44 your host. */ 45#define TYPE_MINIMUM(t) \ 46 ((t) (! TYPE_SIGNED (t) \ 47 ? (t) 0 \ 48 : TYPE_SIGNED_MAGNITUDE (t) \ 49 ? ~ (t) 0 \ 50 : ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1))) 51#define TYPE_MAXIMUM(t) \ 52 ((t) (! TYPE_SIGNED (t) \ 53 ? (t) -1 \ 54 : ~ (~ (t) 0 << (sizeof (t) * CHAR_BIT - 1)))) 55 56/* Return zero if T can be determined to be an unsigned type. 57 Otherwise, return 1. 58 When compiling with GCC, INT_STRLEN_BOUND uses this macro to obtain a 59 tighter bound. Otherwise, it overestimates the true bound by one byte 60 when applied to unsigned types of size 2, 4, 16, ... bytes. 61 The symbol signed_type_or_expr__ is private to this header file. */ 62#if __GNUC__ >= 2 63# define signed_type_or_expr__(t) TYPE_SIGNED (__typeof__ (t)) 64#else 65# define signed_type_or_expr__(t) 1 66#endif 67 68/* Bound on length of the string representing an integer type or expression T. 69 Subtract 1 for the sign bit if T is signed; log10 (2.0) < 146/485; 70 add 1 for integer division truncation; add 1 more for a minus sign 71 if needed. */ 72#define INT_STRLEN_BOUND(t) \ 73 ((sizeof (t) * CHAR_BIT - signed_type_or_expr__ (t)) * 146 / 485 \ 74 + signed_type_or_expr__ (t) + 1) 75 76/* Bound on buffer size needed to represent an integer type or expression T, 77 including the terminating null. */ 78#define INT_BUFSIZE_BOUND(t) (INT_STRLEN_BOUND (t) + 1) 79