1 /* intprops.h -- properties of integer types
3 Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
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.
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.
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/>. */
18 /* Written by Paul Eggert. */
22 /* The extra casts in the following macros work around compiler bugs,
23 e.g., in Cray C 5.0.3.0. */
25 /* True if the arithmetic type T is an integer type. bool counts as
27 #define TYPE_IS_INTEGER(t) ((t) 1.5 == 1)
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)
37 /* True if the arithmetic type T is signed. */
38 #define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
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
44 #define TYPE_MINIMUM(t) \
45 ((t) (! TYPE_SIGNED (t) \
47 : TYPE_SIGNED_MAGNITUDE (t) \
49 : ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1)))
50 #define TYPE_MAXIMUM(t) \
51 ((t) (! TYPE_SIGNED (t) \
53 : ~ (~ (t) 0 << (sizeof (t) * CHAR_BIT - 1))))
55 /* Return zero if T can be determined to be an unsigned type.
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. */
62 # define signed_type_or_expr__(t) TYPE_SIGNED (__typeof__ (t))
64 # define signed_type_or_expr__(t) 1
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
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)
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)