X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;ds=sidebyside;f=lib%2Fintprops.h;h=002161ee57402c4ee89ca7a5da20d4bfbc7858ae;hb=0401ff0087c516234b3bfd07b113f32b95d9d599;hp=cd1c1721215300487a529b3e90bf05c905f8ed70;hpb=eef56b544e01755a52fdfbf204e6f2d5800efd21;p=gnulib.git

diff --git a/lib/intprops.h b/lib/intprops.h
index cd1c17212..002161ee5 100644
--- a/lib/intprops.h
+++ b/lib/intprops.h
@@ -2,10 +2,10 @@
 
    Copyright (C) 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
 
-   This program is free software; you can redistribute it and/or modify
+   This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 2, or (at your option)
-   any later version.
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
 
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ -13,8 +13,7 @@
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
-   along with this program; if not, write to the Free Software Foundation,
-   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 /* Written by Paul Eggert.  */
 
@@ -27,29 +26,52 @@
    an integer.  */
 #define TYPE_IS_INTEGER(t) ((t) 1.5 == 1)
 
-/* True if negative values of the integer type T use twos complement
-   representation.  */
-#define TYPE_TWOS_COMPLEMENT(t) ((t) - (t) 1 == (t) ((t) ~ (t) 1 + (t) 1))
+/* True if negative values of the signed integer type T use two's
+   complement, ones' complement, or signed magnitude representation,
+   respectively.  Much GNU code assumes two's complement, but some
+   people like to be portable to all possible C hosts.  */
+#define TYPE_TWOS_COMPLEMENT(t) ((t) ~ (t) 0 == (t) -1)
+#define TYPE_ONES_COMPLEMENT(t) ((t) ~ (t) 0 == 0)
+#define TYPE_SIGNED_MAGNITUDE(t) ((t) ~ (t) 0 < (t) -1)
 
 /* True if the arithmetic type T is signed.  */
 #define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
 
 /* The maximum and minimum values for the integer type T.  These
-   macros have undefined behavior if T is signed and has padding bits
-   (i.e., bits that do not contribute to the value), or if T uses
-   signed-magnitude representation.  If this is a problem for you,
-   please let us know how to fix it for your host.  */
-#define TYPE_MINIMUM(t) ((t) (TYPE_SIGNED (t) \
-			      ? ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1) : (t) 0))
-#define TYPE_MAXIMUM(t) ((t) (~ (t) 0 - TYPE_MINIMUM (t)))
-
-/* Bound on length of the string representing an integer value or type T.
-   Subtract 1 for the sign bit if t is signed; log10 (2.0) < 146/485;
+   macros have undefined behavior if T is signed and has padding bits.
+   If this is a problem for you, please let us know how to fix it for
+   your host.  */
+#define TYPE_MINIMUM(t) \
+  ((t) (! TYPE_SIGNED (t) \
+	? (t) 0 \
+	: TYPE_SIGNED_MAGNITUDE (t) \
+	? ~ (t) 0 \
+	: ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1)))
+#define TYPE_MAXIMUM(t) \
+  ((t) (! TYPE_SIGNED (t) \
+	? (t) -1 \
+	: ~ (~ (t) 0 << (sizeof (t) * CHAR_BIT - 1))))
+
+/* Return zero if T can be determined to be an unsigned type.
+   Otherwise, return 1.
+   When compiling with GCC, INT_STRLEN_BOUND uses this macro to obtain a
+   tighter bound.  Otherwise, it overestimates the true bound by one byte
+   when applied to unsigned types of size 2, 4, 16, ... bytes.
+   The symbol signed_type_or_expr__ is private to this header file.  */
+#if __GNUC__ >= 2
+# define signed_type_or_expr__(t) TYPE_SIGNED (__typeof__ (t))
+#else
+# define signed_type_or_expr__(t) 1
+#endif
+
+/* Bound on length of the string representing an integer type or expression T.
+   Subtract 1 for the sign bit if T is signed; log10 (2.0) < 146/485;
    add 1 for integer division truncation; add 1 more for a minus sign
    if needed.  */
 #define INT_STRLEN_BOUND(t) \
-  ((sizeof (t) * CHAR_BIT - 1) * 146 / 485 + 2)
+  ((sizeof (t) * CHAR_BIT - signed_type_or_expr__ (t)) * 146 / 485 \
+   + signed_type_or_expr__ (t) + 1)
 
-/* Bound on buffer size needed to represent an integer value or type T,
+/* Bound on buffer size needed to represent an integer type or expression T,
    including the terminating null.  */
 #define INT_BUFSIZE_BOUND(t) (INT_STRLEN_BOUND (t) + 1)