utils: Add a method to get ISO 8601 formated string

Signed-off-by: Siddharth Chandrasekaran <[email protected]>

include/utils/utils.h

@@ -173,6 +173,13 @@ int64_t millis_now();
  */
 void get_time(uint32_t *seconds, uint32_t *micro_seconds);
 
+/**
+ * @brief Addd an ISO 8601 datetime string to `buf` for upto `size` bytes.
+ *
+ * Note: The format is YYYY-MM-DDThh:mm:ssZ, so size must alteast be 21.
+ */
+int add_iso8601_utc_datetime(char *buf, size_t size);
+
 /**
  * @brief Get time elapsed in milli seconds since `last`. Used along with
  * millis_now().

src/utils.c

@@ -9,6 +9,7 @@
 #include <stddef.h>
 #include <ctype.h>
 #include <stdlib.h>
+#include <time.h>
 #include <sys/time.h>
 
 #include <utils/utils.h>
@@ -106,6 +107,15 @@ void get_time(uint32_t *seconds, uint32_t *micro_seconds)
 	*micro_seconds = tv.tv_usec;
 }
 
+int add_iso8601_utc_datetime(char *buf, size_t size)
+{
+	time_t now;
+
+	// Format: YYYY-MM-DDThh:mm:ssZ
+	time(&now);
+	return strftime(buf, size, "%Y-%m-%dT%H:%M:%SZ", gmtime(&now));
+}
+
 int64_t usec_since(int64_t last)
 {
 	return usec_now() - last;