Improve locale support

include/fmt/locale.h

@@ -0,0 +1,47 @@
+// Formatting library for C++ - std::locale support
+//
+// Copyright (c) 2012 - present, Victor Zverovich
+// All rights reserved.
+//
+// For the license information refer to format.h.
+
+#ifndef FMT_LOCALE_H_
+#define FMT_LOCALE_H_
+
+#include "format.h"
+#include <locale>
+
+FMT_BEGIN_NAMESPACE
+
+namespace internal {
+template <typename Char>
+typename buffer_context<Char>::type::iterator vformat_to(
+    const std::locale &loc, basic_buffer<Char> &buf,
+    basic_string_view<Char> format_str,
+    basic_format_args<typename buffer_context<Char>::type> args) {
+  typedef back_insert_range<basic_buffer<Char> > range;
+  return vformat_to<arg_formatter<range>>(
+    buf, to_string_view(format_str), args, internal::locale_ref(loc));
+}
+
+template <typename Char>
+std::basic_string<Char> vformat(
+    const std::locale &loc, basic_string_view<Char> format_str,
+    basic_format_args<typename buffer_context<Char>::type> args) {
+  basic_memory_buffer<Char> buffer;
+  internal::vformat_to(loc, buffer, format_str, args);
+  return fmt::to_string(buffer);
+}
+}
+
+template <typename S, typename... Args>
+inline std::basic_string<FMT_CHAR(S)> format(
+    const std::locale &loc, const S &format_str, const Args &... args) {
+  return internal::vformat(
+    loc, to_string_view(format_str),
+    *internal::checked_args<S, Args...>(format_str, args...));
+}
+
+FMT_END_NAMESPACE
+
+#endif  // FMT_LOCALE_H_