1 files changed, 59 insertions, 0 deletions
diff --git a/bitncmp.c b/bitncmp.c
new file mode 100644
index 0000000..5c89506
--- /dev/null
+++ b/bitncmp.c
@@ -0,0 +1,59 @@
+
+/*
+ * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
+ * Copyright (c) 1996,1999 by Internet Software Consortium.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
+ * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#ifndef HAVE_BITNCMP
+
+#include "ares_setup.h"
+#include "bitncmp.h"
+
+/*
+ * int
+ * bitncmp(l, r, n)
+ *	compare bit masks l and r, for n bits.
+ * return:
+ *	-1, 1, or 0 in the libc tradition.
+ * note:
+ *	network byte order assumed.  this means 192.5.5.240/28 has
+ *	0x11110000 in its fourth octet.
+ * author:
+ *	Paul Vixie (ISC), June 1996
+ */
+int
+ares_bitncmp(const void *l, const void *r, int n) {
+	unsigned int lb, rb;
+	int x, b;
+
+	b = n / 8;
+	x = memcmp(l, r, b);
+	if (x || (n % 8) == 0)
+		return (x);
+
+	lb = ((const unsigned char *)l)[b];
+	rb = ((const unsigned char *)r)[b];
+	for (b = n % 8; b > 0; b--) {
+		if ((lb & 0x80) != (rb & 0x80)) {
+			if (lb & 0x80)
+				return (1);
+			return (-1);
+		}
+		lb <<= 1;
+		rb <<= 1;
+	}
+	return (0);
+}
+#endif