X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fintprops.h;h=34f971cbaad8c1a0504163d34cf766254dbf4002;hb=c5ce79f4c514b37b5756e85530112d778cff302a;hp=d36c182f4038acaf8d7abd4e23866d41dcac41d4;hpb=d3aea660de14898af6f8f03d452f58b28126dabc;p=gnulib.git

diff --git a/lib/intprops.h b/lib/intprops.h
index d36c182f4..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.  */
 
@@ -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.  */