84 lines
3.2 KiB
C
84 lines
3.2 KiB
C
/* intprops.h -- properties of integer types
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Copyright (C) 2001, 2002, 2003, 2004, 2005, 2009, 2010 Free Software
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Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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/* Written by Paul Eggert. */
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#ifndef GL_INTPROPS_H
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# define GL_INTPROPS_H
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# include <limits.h>
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/* The extra casts in the following macros work around compiler bugs,
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e.g., in Cray C 5.0.3.0. */
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/* True if the arithmetic type T is an integer type. bool counts as
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an integer. */
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# define TYPE_IS_INTEGER(t) ((t) 1.5 == 1)
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/* True if negative values of the signed integer type T use two's
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complement, ones' complement, or signed magnitude representation,
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respectively. Much GNU code assumes two's complement, but some
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people like to be portable to all possible C hosts. */
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# define TYPE_TWOS_COMPLEMENT(t) ((t) ~ (t) 0 == (t) -1)
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# define TYPE_ONES_COMPLEMENT(t) ((t) ~ (t) 0 == 0)
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# define TYPE_SIGNED_MAGNITUDE(t) ((t) ~ (t) 0 < (t) -1)
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/* True if the arithmetic type T is signed. */
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# define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
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/* The maximum and minimum values for the integer type T. These
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macros have undefined behavior if T is signed and has padding bits.
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If this is a problem for you, please let us know how to fix it for
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your host. */
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# define TYPE_MINIMUM(t) \
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((t) (! TYPE_SIGNED (t) \
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? (t) 0 \
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: TYPE_SIGNED_MAGNITUDE (t) \
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? ~ (t) 0 \
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: ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1)))
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# define TYPE_MAXIMUM(t) \
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((t) (! TYPE_SIGNED (t) \
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? (t) -1 \
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: ~ (~ (t) 0 << (sizeof (t) * CHAR_BIT - 1))))
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/* Return zero if T can be determined to be an unsigned type.
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Otherwise, return 1.
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When compiling with GCC, INT_STRLEN_BOUND uses this macro to obtain a
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tighter bound. Otherwise, it overestimates the true bound by one byte
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when applied to unsigned types of size 2, 4, 16, ... bytes.
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The symbol signed_type_or_expr__ is private to this header file. */
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# if __GNUC__ >= 2
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# define signed_type_or_expr__(t) TYPE_SIGNED (__typeof__ (t))
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# else
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# define signed_type_or_expr__(t) 1
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# endif
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/* Bound on length of the string representing an integer type or expression T.
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Subtract 1 for the sign bit if T is signed; log10 (2.0) < 146/485;
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add 1 for integer division truncation; add 1 more for a minus sign
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if needed. */
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# define INT_STRLEN_BOUND(t) \
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((sizeof (t) * CHAR_BIT - signed_type_or_expr__ (t)) * 146 / 485 \
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+ signed_type_or_expr__ (t) + 1)
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/* Bound on buffer size needed to represent an integer type or expression T,
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including the terminating null. */
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# define INT_BUFSIZE_BOUND(t) (INT_STRLEN_BOUND (t) + 1)
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#endif /* GL_INTPROPS_H */
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