Time range support for vppinfra

Change-Id: I2356b1e05fd868b46b4d26ade760900a5739ca4d
Signed-off-by: Dave Barach <dave@barachs.net>
diff --git a/src/vppinfra/time_range.h b/src/vppinfra/time_range.h
new file mode 100644
index 0000000..6dcd82d
--- /dev/null
+++ b/src/vppinfra/time_range.h
@@ -0,0 +1,131 @@
+/*
+ * Copyright (c) 2018 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef included_time_range_h
+#define included_time_range_h
+
+#include <vppinfra/format.h>
+#include <vppinfra/time.h>
+
+typedef enum
+{
+  CLIB_TIMEBASE_DAYLIGHT_NONE = 0,
+  CLIB_TIMEBASE_DAYLIGHT_USA,
+} clib_timebase_daylight_time_t;
+
+typedef struct
+{
+  /* provides f64 seconds since clib_time_init was called */
+  clib_time_t clib_time;
+  /*
+   * time in f64 seconds since Thursday 1 Jan 1970 00:00:00 UTC
+   * when clib_time_init was called
+   */
+  f64 time_zero;
+  f64 timezone_offset;
+  f64 summer_offset;
+  clib_timebase_daylight_time_t daylight_time_type;
+  f64 cached_year_start;
+  f64 cached_year_end;
+  f64 cached_summer_start;
+  f64 cached_summer_end;
+} clib_timebase_t;
+
+typedef struct
+{
+  u32 year, month, day, hour, minute, second, nanosecond;
+  /* 0 => Thursday */
+  u32 day_name_index;
+  f64 fractional_seconds;
+} clib_timebase_component_t;
+
+typedef struct
+{
+  f64 start, end;
+} clib_timebase_range_t;
+
+void clib_timebase_init (clib_timebase_t * tb, i32 timezone_offset_in_hours,
+			 clib_timebase_daylight_time_t daylight_type);
+
+void clib_timebase_time_to_components (f64 now,
+				       clib_timebase_component_t * cp);
+
+f64 clib_timebase_components_to_time (clib_timebase_component_t * cp);
+
+f64 clib_timebase_find_sunday_midnight (f64 start_time);
+f64 clib_timebase_offset_from_sunday (u8 * day);
+f64 clib_timebase_summer_offset (clib_timebase_t * tb, f64 now);
+
+unformat_function_t unformat_clib_timebase_range_hms;
+unformat_function_t unformat_clib_timebase_range_vector;
+
+format_function_t format_clib_timebase_time;
+
+static inline f64 clib_timebase_summer_offset_fastpath
+  (clib_timebase_t * tb, f64 now)
+{
+  if (PREDICT_TRUE
+      (now >= tb->cached_year_start && now <= tb->cached_year_end))
+    {
+      if (now >= tb->cached_summer_start && now <= tb->cached_summer_end)
+	return tb->summer_offset;
+      else
+	return 0.0;
+    }
+  else
+    return clib_timebase_summer_offset (tb, now);
+}
+
+static inline f64
+clib_timebase_now (clib_timebase_t * tb)
+{
+  f64 now;
+
+  now = tb->time_zero + clib_time_now (&tb->clib_time);
+  now += tb->timezone_offset;
+  now += clib_timebase_summer_offset_fastpath (tb, now);
+
+  return now;
+}
+
+static inline int
+clib_timebase_is_leap_year (u32 year)
+{
+  int rv;
+
+  if (PREDICT_TRUE ((year % 4) != 0))
+    return 0;
+
+  rv = 0;
+
+  if ((year % 4) == 0)
+    rv = 1;
+  if ((year % 100) == 0)
+    rv = 0;
+  if ((year % 400) == 0)
+    rv = 1;
+  return rv;
+}
+
+#endif /* included_time_range_h */
+
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */