Add an abstract time value type.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>

tmv.h

@@ -0,0 +1,72 @@
+/**
+ * @file tmv.h
+ * @brief Implements an abstract time value type.
+ * @note Copyright (C) 2011 Richard Cochran <richardcochran@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#ifndef HAVE_TMV_H
+#define HAVE_TMV_H
+
+#include "ddt.h"
+#include "pdt.h"
+
+#define NS_PER_SEC 1000000000LL
+
+/**
+ * We implement the time value as a 64 bit signed integer containing
+ * nanoseconds. Using this representation, we could really spare the
+ * arithmetic functions such as @ref tmv_add() and the like, and just
+ * use plain old math operators in the code.
+ *
+ * However, we are going to be a bit pendandic here and enforce the
+ * use of the these functions, so that we can easily upgrade the code
+ * to a finer representation later on. In that way, we can make use of
+ * the fractional nanosecond parts of the correction fields, if and
+ * when people start asking for them.
+ */
+typedef int64_t tmv_t;
+
+static inline tmv_t tmv_add(tmv_t a, tmv_t b)
+{
+	return a + b;
+}
+
+static inline tmv_t tmv_div(tmv_t a, int divisor)
+{
+	return a / divisor;
+}
+
+static inline tmv_t tmv_sub(tmv_t a, tmv_t b)
+{
+	return a - b;
+}
+
+static inline tmv_t correction_to_tmv(Integer64 c)
+{
+	return c >> 16;
+}
+
+static inline tmv_t timespec_to_tmv(struct timespec ts)
+{
+	return ts.tv_sec * NS_PER_SEC + ts.tv_nsec;
+}
+
+static inline tmv_t timestamp_to_tmv(struct timestamp ts)
+{
+	return ts.sec * NS_PER_SEC + ts.nsec;
+}
+
+#endif