From 29e1b81ce4bad922c523fcfdfda99c58aafa1af2 Mon Sep 17 00:00:00 2001
From: Sebastian Harl <sh@tokkee.org>
Date: Sat, 18 Aug 2012 18:11:39 +0200
Subject: [PATCH] utils_time: Added cdtime_to_iso8601() function.

This function formats a cdtime_t value in ISO 8601 format (and ensures that
the string is null terminated).
---
 src/utils_time.c | 30 ++++++++++++++++++++++++++++++
 src/utils_time.h |  6 ++++++
 2 files changed, 36 insertions(+)

diff --git a/src/utils_time.c b/src/utils_time.c
index aac6135e..f30dc0fa 100644
--- a/src/utils_time.c
+++ b/src/utils_time.c
@@ -61,4 +61,34 @@ cdtime_t cdtime (void) /* {{{ */
 } /* }}} cdtime_t cdtime */
 #endif
 
+size_t cdtime_to_iso8601 (char *s, size_t max, cdtime_t t) /* {{{ */
+{
+  struct timespec t_spec;
+  struct tm t_tm;
+
+  size_t len;
+
+  CDTIME_T_TO_TIMESPEC (t, &t_spec);
+  NORMALIZE_TIMESPEC (t_spec);
+
+  if (localtime_r ((time_t *)&t_spec.tv_sec, &t_tm) == NULL) {
+    char errbuf[1024];
+    ERROR ("cdtime_to_iso8601: localtime_r failed: %s",
+        sstrerror (errno, errbuf, sizeof (errbuf)));
+    return (0);
+  }
+
+  len = strftime (s, max, "%Y-%m-%dT%H:%M:%S", &t_tm);
+  if (len == 0)
+    return 0;
+
+  if (max - len > 2) {
+    int n = snprintf (s + len, max - len, ".%09i", (int)t_spec.tv_nsec);
+    len += (n < max - len) ? n : max - len;
+  }
+
+  s[max - 1] = '\0';
+  return len;
+} /* }}} size_t cdtime_to_iso8601 */
+
 /* vim: set sw=2 sts=2 et fdm=marker : */
diff --git a/src/utils_time.h b/src/utils_time.h
index 0fd809ac..0081957d 100644
--- a/src/utils_time.h
+++ b/src/utils_time.h
@@ -66,5 +66,11 @@
 
 cdtime_t cdtime (void);
 
+/* format a cdtime_t value in ISO 8601 format:
+ * returns the number of characters written to the string (not including the
+ * terminating null byte or 0 on error; the function ensures that the string
+ * is null terminated */
+size_t cdtime_to_iso8601 (char *s, size_t max, cdtime_t t);
+
 #endif /* UTILS_TIME_H */
 /* vim: set sw=2 sts=2 et : */
-- 
2.30.2