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    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)