1 files changed, 58 insertions, 0 deletions
diff --git a/contrib/ntp/libntp/refidsmear.c b/contrib/ntp/libntp/refidsmear.c
new file mode 100644
index 0000000000000..fef428e8a226e
--- /dev/null
+++ b/contrib/ntp/libntp/refidsmear.c
@@ -0,0 +1,58 @@
+#include <config.h>
+
+#include <ntp.h>
+#include <ntp_fp.h>
+#include <refidsmear.h>
+
+/*
+ * we want to test a refid format of:
+ * 254.x.y.x
+ *
+ * where x.y.z are 24 bits containing 2 (signed) integer bits
+ * and 22 fractional bits.
+ *
+ */
+
+
+l_fp
+convertRefIDToLFP(uint32_t r)
+{
+	l_fp temp;
+
+	r = ntohl(r);
+
+	// printf("%03d %08x: ", (r >> 24) & 0xFF, (r & 0x00FFFFFF) );
+
+	temp.l_uf = (r << 10);	/* 22 fractional bits */
+
+	temp.l_ui = (r >> 22) & 0x3;
+	temp.l_ui |= ~(temp.l_ui & 2) + 1;
+
+	return temp;
+}
+
+
+uint32_t
+convertLFPToRefID(l_fp num)
+{
+	uint32_t temp;
+
+	/* round the input with the highest bit to shift out from the
+	 * fraction, then keep just two bits from the integral part.
+	 *
+	 * TODO: check for overflows; should we clamp/saturate or just
+	 * complain?
+	 */
+	L_ADDUF(&num, 0x200);
+	num.l_ui &= 3;
+
+	/* combine integral and fractional part to 24 bits */
+	temp  = (num.l_ui << 22) | (num.l_uf >> 10);
+
+	/* put in the leading 254.0.0.0 */
+	temp |= UINT32_C(0xFE000000);
+
+	// printf("%03d %08x: ", (temp >> 24) & 0xFF, (temp & 0x00FFFFFF) );
+
+	return htonl(temp);
+}