1 files changed, 47 insertions, 0 deletions
diff --git a/src/include/utime_fmt.h b/src/include/utime_fmt.h
new file mode 100644
index 000000000..e7a98d209
--- /dev/null
+++ b/src/include/utime_fmt.h
@@ -0,0 +1,47 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+#pragma once
+/**
+ * \file fmtlib formatter for utime_t
+ */
+#include <fmt/chrono.h>
+#include <fmt/format.h>
+
+#include "include/utime.h"
+
+template <>
+struct fmt::formatter<utime_t> {
+  template <typename ParseContext>
+  constexpr auto parse(ParseContext& ctx)
+  {
+    auto it = ctx.begin();
+    if (it != ctx.end() && *it == 's') {
+      short_format = true;
+      ++it;
+    }
+    return it;
+  }
+
+  template <typename FormatContext>
+  auto format(const utime_t& utime, FormatContext& ctx)
+  {
+    if (utime.sec() < ((time_t)(60 * 60 * 24 * 365 * 10))) {
+      // raw seconds.  this looks like a relative time.
+      return fmt::format_to(ctx.out(), "{}.{:06}", (long)utime.sec(),
+			    utime.usec());
+    }
+
+    // this looks like an absolute time.
+    // conform to http://en.wikipedia.org/wiki/ISO_8601
+    // (unless short_format is set)
+    auto aslocal = fmt::localtime(utime.sec());
+    if (short_format) {
+      return fmt::format_to(ctx.out(), "{:%FT%T}.{:03}", aslocal,
+			    utime.usec() / 1000);
+    }
+    return fmt::format_to(ctx.out(), "{:%FT%T}.{:06}{:%z}", aslocal,
+			  utime.usec(), aslocal);
+  }
+
+  bool short_format{false};
+};