--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/str_diffn.c	Fri Oct 19 14:06:22 2007 +0200
@@ -0,0 +1,18 @@
+#include "str.h"
+
+int str_diffn(s,t,len)
+register char *s;
+register char *t;
+unsigned int len;
+{
+  register char x;
+
+  for (;;) {
+    if (!len--) return 0; x = *s; if (x != *t) break; if (!x) break; ++s; ++t;
+    if (!len--) return 0; x = *s; if (x != *t) break; if (!x) break; ++s; ++t;
+    if (!len--) return 0; x = *s; if (x != *t) break; if (!x) break; ++s; ++t;
+    if (!len--) return 0; x = *s; if (x != *t) break; if (!x) break; ++s; ++t;
+  }
+  return ((int)(unsigned int)(unsigned char) x)
+       - ((int)(unsigned int)(unsigned char) *t);
+}