X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fintprops.h;h=34f971cbaad8c1a0504163d34cf766254dbf4002;hb=20229ba96d971f97ff03ab74eeb4e7de1acccf98;hp=409e0f1d4d41a5dae388907f9f14cacedd0d2099;hpb=d6913e92bfd13a918b19223fb676e9c0f136400e;p=gnulib.git

diff --git a/lib/intprops.h b/lib/intprops.h
index 409e0f1d4..34f971cba 100644
--- a/lib/intprops.h
+++ b/lib/intprops.h
@@ -14,7 +14,7 @@
 
    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.  */
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
 
 /* Written by Paul Eggert.  */
 
@@ -28,7 +28,7 @@
 #define TYPE_IS_INTEGER(t) ((t) 1.5 == 1)
 
 /* True if negative values of the signed integer type T use two's
-   complement, one's complement, or signed magnitude representation,
+   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)
@@ -53,12 +53,25 @@
 	? (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;
+   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 type or expression T,
    including the terminating null.  */