Simplify prefix_cmp.

util.c

@@ -494,25 +494,22 @@ enum prefix_status
 prefix_cmp(const unsigned char *p1, unsigned char plen1,
            const unsigned char *p2, unsigned char plen2)
 {
-    int min = MIN(plen1, plen2);
-    unsigned char mask = 0xFF;
-    int i = 0;
+    int plen = MIN(plen1, plen2);
 
-    while(i < min / 8) {
-        if(p1[i] != p2[i])
-            return PST_DISJOINT;
-        i++;
-    }
-    min -= i * 8;
-    if(min != 0) {
-        mask <<= 8 - min;
+    if(memcmp(p1, p2, plen / 8) != 0)
+        return PST_DISJOINT;
+
+    if(plen % 8 != 0) {
+        int i = plen / 8 + 1;
+        unsigned char mask = (0xFF << (plen % 8)) & 0xFF;
         if((p1[i] & mask) != (p2[i] & mask))
             return PST_DISJOINT;
     }
 
     if(plen1 < plen2)
         return PST_LESS_SPECIFIC;
-    if(plen1 > plen2)
+    else if(plen1 > plen2)
         return PST_MORE_SPECIFIC;
-    return PST_EQUALS;
+    else
+        return PST_EQUALS;
 }