(my_strtoumax): Fix typo in computing

whether overflow occurred.  Improve overflow-detection to use
only one conditional branch total, rather than 2N+1
conditional branches for an N-digit number.

diff --git a/lib/xstrtoumax.c b/lib/xstrtoumax.c
index 40f0d78..9ef799b 100644 (file)
--- a/lib/xstrtoumax.c
+++ b/lib/xstrtoumax.c
@@ -78,12 +78,12 @@ my_strtoumax (char const *ptr, char **endptr, int base)
     /* An implementation with uintmax_t longer than long, but with no
        known way to convert it.  Do it by hand.  Assume base 10.  */
     uintmax_t n = 0;
-    int overflow = 0;
+    uintmax_t overflow = 0;
     for (;  '0' <= *ptr && *ptr <= '9';  ptr++)
       {
        uintmax_t n10 = n * 10;
        int digit = *ptr - '0';
-       overflow |= ! (n10 / 10 == n && n10 < n10 + digit);
+       overflow |= n ^ (n10 + digit) / 10;
        n = n10 + digit;
       }
     if (endptr)