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