From e460978379cc477e806251ba38cb426b2aa9fddf Mon Sep 17 00:00:00 2001
From: Sebastian Harl <sh@tokkee.org>
Date: Wed, 30 Jul 2014 10:24:30 +0200
Subject: [PATCH] time: Added sdb_strpunit() to parse a time unit.

---
 src/core/time.c         | 28 +++++++++++++++++++++++++++-
 src/frontend/scanner.l  |  6 ++++++
 src/include/core/time.h | 13 +++++++++++++
 t/unit/core/time_test.c | 39 ++++++++++++++++++++++++++++++++++++++-
 4 files changed, 84 insertions(+), 2 deletions(-)

diff --git a/src/core/time.c b/src/core/time.c
index 762ffd0..5d34e18 100644
--- a/src/core/time.c
+++ b/src/core/time.c
@@ -41,7 +41,7 @@
  * public API
  */
 
-/* 1 second (in micro-seconds) */
+/* 1 second (in nano-seconds) */
 #define SEC 1000000000L
 
 const sdb_time_t SDB_INTERVAL_YEAR   = 3652425L   * 24L * 60L * 60L * 100000L;
@@ -147,5 +147,31 @@ sdb_strfinterval(char *s, size_t len, sdb_time_t interval)
 	return n;
 } /* sdb_strfinterval */
 
+sdb_time_t
+sdb_strpunit(const char *s)
+{
+	struct {
+		const char *s;
+		sdb_time_t unit;
+	} units[] = {
+		{ "Y", SDB_INTERVAL_YEAR },
+		{ "M", SDB_INTERVAL_MONTH },
+		{ "D", SDB_INTERVAL_DAY },
+		{ "h", SDB_INTERVAL_HOUR },
+		{ "m", SDB_INTERVAL_MINUTE },
+		{ "s", SDB_INTERVAL_SECOND },
+		{ "ms", SDB_INTERVAL_SECOND / 1000L },
+		{ "us", SDB_INTERVAL_SECOND / 1000000L },
+		{ "ns", 1 },
+	};
+
+	size_t i;
+
+	for (i = 0; i < SDB_STATIC_ARRAY_LEN(units); ++i)
+		if (! strcmp(s, units[i].s))
+			return units[i].unit;
+	return 0;
+} /* sdb_strpunit */
+
 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */
 
diff --git a/src/frontend/scanner.l b/src/frontend/scanner.l
index 5e80368..f45fbe7 100644
--- a/src/frontend/scanner.l
+++ b/src/frontend/scanner.l
@@ -75,10 +75,16 @@ csc_start	\/\*
 csc_inside	([^*/]+|[^*]\/|\*[^/])
 csc_end		\*\/
 
+/*
+ * Strings and identifiers.
+ */
 identifier	([A-Za-z_][A-Za-z_0-9$]*)
 /* TODO: fully support SQL strings */
 string		('[^']*')
 
+/*
+ * Numeric constants.
+ */
 dec			([\+\-]?[0-9]+)
 exp			([\+\-]?[0-9]+[Ee]\+?[0-9]+)
 integer		({dec}|{exp})
diff --git a/src/include/core/time.h b/src/include/core/time.h
index 7515af3..c97e121 100644
--- a/src/include/core/time.h
+++ b/src/include/core/time.h
@@ -79,6 +79,19 @@ sdb_strftime(char *s, size_t len, const char *format, sdb_time_t);
 size_t
 sdb_strfinterval(char *s, size_t len, sdb_time_t interval);
 
+/*
+ * sdb_strpunit:
+ * Parse the specified string as a time unit.
+ * "Y" (year), "M" (month), "D" (day), "h" (hour), "m" (minute), "s" (second),
+ * "ms" (milli-second), "us" (micro-second), "ns" (nano-second).
+ *
+ * Returns:
+ *  - the time interval corresponding to the specified unit on success
+ *  - 0 else
+ */
+sdb_time_t
+sdb_strpunit(const char *s);
+
 #ifdef __cplusplus
 } /* extern "C" */
 #endif
diff --git a/t/unit/core/time_test.c b/t/unit/core/time_test.c
index f1f4c94..8be2214 100644
--- a/t/unit/core/time_test.c
+++ b/t/unit/core/time_test.c
@@ -34,7 +34,6 @@ START_TEST(test_strfinterval)
 {
 	char buf[1024];
 	size_t check;
-	size_t i;
 
 	struct {
 		sdb_time_t  interval;
@@ -59,6 +58,8 @@ START_TEST(test_strfinterval)
 		  + 1234,               "1Y1M1D1h1m1.000001234s" },
 	};
 
+	size_t i;
+
 	/* this should return the number of bytes which would have been written;
 	 * most notably, it should not segfault ;-) */
 	check = sdb_strfinterval(NULL, 0, 4711); /* expected: .000004711s */
@@ -82,6 +83,41 @@ START_TEST(test_strfinterval)
 }
 END_TEST
 
+START_TEST(test_strpunit)
+{
+	struct {
+		const char *s;
+		sdb_time_t expected;
+	} golden_data[] = {
+		{ "Y",  SDB_INTERVAL_YEAR },
+		{ "M",  SDB_INTERVAL_MONTH },
+		{ "D",  SDB_INTERVAL_DAY },
+		{ "h",  SDB_INTERVAL_HOUR },
+		{ "m",  SDB_INTERVAL_MINUTE },
+		{ "s",  SDB_INTERVAL_SECOND },
+		{ "ms", 1000000L },
+		{ "us", 1000L },
+		{ "ns", 1L },
+		/* invalid units */
+		{ "y",  0 },
+		{ "d",  0 },
+		{ "H",  0 },
+		{ "S",  0 },
+		{ "ps", 0 },
+	};
+
+	size_t i;
+
+	for (i = 0; i < SDB_STATIC_ARRAY_LEN(golden_data); ++i) {
+		sdb_time_t check = sdb_strpunit(golden_data[i].s);
+
+		fail_unless(check == golden_data[i].expected,
+				"sdb_strpunit(%s) = %"PRIsdbTIME"; expected: %"PRIsdbTIME,
+				golden_data[i].s, check, golden_data[i].expected);
+	}
+}
+END_TEST
+
 Suite *
 core_time_suite(void)
 {
@@ -90,6 +126,7 @@ core_time_suite(void)
 
 	tc = tcase_create("core");
 	tcase_add_test(tc, test_strfinterval);
+	tcase_add_test(tc, test_strpunit);
 	suite_add_tcase(s, tc);
 
 	return s;
-- 
2.30.2