| 1 | /* intprops.h -- properties of integer types
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| 2 |
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| 3 | Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
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| 4 |
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| 5 | This program is free software; you can redistribute it and/or modify
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| 6 | it under the terms of the GNU General Public License as published by
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| 7 | the Free Software Foundation; either version 2, or (at your option)
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| 8 | any later version.
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| 9 |
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| 10 | This program is distributed in the hope that it will be useful,
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| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 13 | GNU General Public License for more details.
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| 14 |
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| 15 | You should have received a copy of the GNU General Public License
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| 16 | along with this program; if not, write to the Free Software Foundation,
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| 17 | Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
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| 18 |
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| 19 | /* Written by Paul Eggert. */
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| 20 |
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| 21 | #include <limits.h>
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| 22 |
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| 23 | /* The extra casts in the following macros work around compiler bugs,
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| 24 | e.g., in Cray C 5.0.3.0. */
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| 25 |
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| 26 | /* True if the arithmetic type T is an integer type. bool counts as
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| 27 | an integer. */
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| 28 | #define TYPE_IS_INTEGER(t) ((t) 1.5 == 1)
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| 29 |
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| 30 | /* True if negative values of the signed integer type T use two's
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| 31 | complement, ones' complement, or signed magnitude representation,
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| 32 | respectively. Much GNU code assumes two's complement, but some
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| 33 | people like to be portable to all possible C hosts. */
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| 34 | #define TYPE_TWOS_COMPLEMENT(t) ((t) ~ (t) 0 == (t) -1)
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| 35 | #define TYPE_ONES_COMPLEMENT(t) ((t) ~ (t) 0 == 0)
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| 36 | #define TYPE_SIGNED_MAGNITUDE(t) ((t) ~ (t) 0 < (t) -1)
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| 37 |
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| 38 | /* True if the arithmetic type T is signed. */
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| 39 | #define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
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| 40 |
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| 41 | /* The maximum and minimum values for the integer type T. These
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| 42 | macros have undefined behavior if T is signed and has padding bits.
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| 43 | If this is a problem for you, please let us know how to fix it for
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| 44 | your host. */
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| 45 | #define TYPE_MINIMUM(t) \
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| 46 | ((t) (! TYPE_SIGNED (t) \
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| 47 | ? (t) 0 \
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| 48 | : TYPE_SIGNED_MAGNITUDE (t) \
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| 49 | ? ~ (t) 0 \
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| 50 | : ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1)))
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| 51 | #define TYPE_MAXIMUM(t) \
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| 52 | ((t) (! TYPE_SIGNED (t) \
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| 53 | ? (t) -1 \
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| 54 | : ~ (~ (t) 0 << (sizeof (t) * CHAR_BIT - 1))))
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| 55 |
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| 56 | /* Return zero if T can be determined to be an unsigned type.
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| 57 | Otherwise, return 1.
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| 58 | When compiling with GCC, INT_STRLEN_BOUND uses this macro to obtain a
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| 59 | tighter bound. Otherwise, it overestimates the true bound by one byte
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| 60 | when applied to unsigned types of size 2, 4, 16, ... bytes.
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| 61 | The symbol signed_type_or_expr__ is private to this header file. */
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| 62 | #if __GNUC__ >= 2
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| 63 | # define signed_type_or_expr__(t) TYPE_SIGNED (__typeof__ (t))
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| 64 | #else
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| 65 | # define signed_type_or_expr__(t) 1
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| 66 | #endif
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| 67 |
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| 68 | /* Bound on length of the string representing an integer type or expression T.
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| 69 | Subtract 1 for the sign bit if T is signed; log10 (2.0) < 146/485;
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| 70 | add 1 for integer division truncation; add 1 more for a minus sign
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| 71 | if needed. */
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| 72 | #define INT_STRLEN_BOUND(t) \
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| 73 | ((sizeof (t) * CHAR_BIT - signed_type_or_expr__ (t)) * 146 / 485 \
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| 74 | + signed_type_or_expr__ (t) + 1)
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| 75 |
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| 76 | /* Bound on buffer size needed to represent an integer type or expression T,
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| 77 | including the terminating null. */
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| 78 | #define INT_BUFSIZE_BOUND(t) (INT_STRLEN_BOUND (t) + 1)
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