From 9ec06749f253c6a2b0ecea10fffc0022acd930ca Mon Sep 17 00:00:00 2001
From: Jose Marcial Vieira Bisneto <marcial.vieirab@gmail.com>
Date: Tue, 13 Dec 2016 22:16:51 -0300
Subject: [PATCH] Initial implementation of util/time.c

---
 include/ipfs/util/time.h | 12 ++++++++
 util/time.c              | 59 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 71 insertions(+)
 create mode 100644 include/ipfs/util/time.h
 create mode 100644 util/time.c

diff --git a/include/ipfs/util/time.h b/include/ipfs/util/time.h
new file mode 100644
index 0000000..3d49f5c
--- /dev/null
+++ b/include/ipfs/util/time.h
@@ -0,0 +1,12 @@
+#ifndef IPFS_TIME_H
+    #define IPFS_TIME_H
+
+    struct stime {
+        time_t t;
+        struct timespec ts;
+    };
+
+    int get_gmttime(struct stime *st);
+    int ipfs_util_time_parse_RFC3339 (struct stime *st, char *s);
+    char *ipfs_util_time_format_RFC3339 (struct stime *st);
+#endif // IPFS_TIME_H
diff --git a/util/time.c b/util/time.c
new file mode 100644
index 0000000..b438eb8
--- /dev/null
+++ b/util/time.c
@@ -0,0 +1,59 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifndef __USE_XOPEN
+    #define __USE_XOPEN
+#endif // __USE_XOPEN
+
+#ifndef __USE_ISOC11
+    #define __USE_ISOC11
+#endif // __USE_ISOC11
+
+#include <time.h>
+#include "ipfs/util/time.h"
+
+int get_gmttime(struct stime *st) {
+    if (!st) {
+        return 1;
+    }
+    if (!timespec_get(&st->ts, TIME_UTC) ||
+        !time(&st->t)) {
+        return 2;
+    }
+    return 0;
+}
+
+int ipfs_util_time_parse_RFC3339 (struct stime *st, char *s)
+{
+    char *r;
+    struct tm tm;
+
+    if (!st || !s || strlen(s) != 35) {
+        return 1;
+    }
+    r = strptime (s, "%Y-%m-%dT%H:%M:%S", &tm);
+    if (!r || *r != '.') {
+        return 2;
+    }
+    st->t = mktime(&tm);
+    st->ts.tv_nsec = atoll(++r);
+    return 0;
+}
+
+char *ipfs_util_time_format_RFC3339 (struct stime *st)
+{
+    char buf[31], *ret;
+
+    ret = malloc(36);
+    if (!ret) {
+        return NULL;
+    }
+
+    if (strftime(buf, sizeof(buf), "%Y-%m-%dT%H:%M:%S.%%09dZ00:00", gmtime(&st->t)) != sizeof(buf)-1 ||
+        snprintf(ret, 36, buf, st->ts.tv_nsec) != 35) {
+        free (ret);
+        return NULL;
+    }
+    return ret;
+}