From 5aac5aab2ce8144412f2255d5c0b48cbaa9039d7 Mon Sep 17 00:00:00 2001
From: Chris Frey <cdfrey@foursquare.net>
Date: Sat, 17 Jul 2010 00:08:50 -0400
Subject: [PATCH] lib: added tm_to_iso() to tzwrapper functions

---
 ChangeLog        |  2 ++
 src/tzwrapper.cc | 27 +++++++++++++++++++++++++++
 src/tzwrapper.h  |  9 +++++++++
 3 files changed, 38 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index 2ba164f3..d24b8d61 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,7 @@
 Release: version 0.17 - 2010/01/??
 ------------------------------------------------------------------------------
+2010/07/17
+	- lib: added tm_to_iso() to tzwrapper functions
 2010/07/16
 	- lib: added BARRY_GCC_FORMAT_CHECK() for printf() style arg checking
 	- lib: added C-style BarryLogf() function for internal use
diff --git a/src/tzwrapper.cc b/src/tzwrapper.cc
index b5acef07..18c84c0d 100644
--- a/src/tzwrapper.cc
+++ b/src/tzwrapper.cc
@@ -79,6 +79,31 @@ struct tm* iso_to_tm(const char *timestamp,
 	return (found >= 6) ? result : 0;
 }
 
+std::string tm_to_iso(const struct tm *t, bool utc)
+{
+	char tmp[128];
+
+	int cc = snprintf(tmp, sizeof(tmp), "%04d%02d%02dT%02d%02d%02d",
+		t->tm_year + 1900,
+		t->tm_mon + 1,
+		t->tm_mday,
+		t->tm_hour,
+		t->tm_min,
+		t->tm_sec
+		);
+	if( cc < 0 || (size_t)cc >= sizeof(tmp) )
+		return "";
+
+	if( utc ) {
+		if( (size_t)cc >= (sizeof(tmp) - 1) )
+			return "";		// not enough room for Z
+		tmp[cc++] = 'Z';
+		tmp[cc] = 0;
+	}
+
+	return tmp;
+}
+
 time_t TzWrapper::iso_mktime(const char *timestamp)
 {
 	bool utc;
@@ -131,6 +156,8 @@ int main()
 		cout << "Fail check: passed" << endl;
 	else
 		cout << "Fail check: ERROR" << endl;
+
+	cout << "t1: " << tm_to_iso(gmtime(&t1), true) << endl;
 }
 #endif
 
diff --git a/src/tzwrapper.h b/src/tzwrapper.h
index 8a6a5c80..f4825943 100644
--- a/src/tzwrapper.h
+++ b/src/tzwrapper.h
@@ -29,6 +29,15 @@ BXEXPORT struct tm* iso_to_tm(const char *timestamp,
 				struct tm *result,
 				bool &utc);
 
+/// Turns the struct tm into an ISO timestamp in the format
+/// of YYYYMMDDTHHMMSS[Z].  The Z is appended if utc is true.
+/// This function assumes that t contains sane values, and will
+/// create the target string directly from its content.
+/// Returns the ISO timestamp, or empty string on error.
+/// If t contains sane values, this function should never fail.
+/// Thread-safe.
+BXEXPORT std::string tm_to_iso(const struct tm *t, bool utc);
+
 /// utc_mktime() converts a struct tm that contains
 /// broken down time in utc to a time_t.  This function uses
 /// a brute-force method of conversion that does not require
-- 
2.11.4.GIT