From 0508bbc7ae4d1509b6588e1a536bd86c0694edf6 Mon Sep 17 00:00:00 2001
From: Victor Zverovich <victor.zverovich@gmail.com>
Date: Wed, 13 Jun 2018 08:24:32 +0200
Subject: [PATCH] Add wchar_t overload of format_to_n (#764)

---
 include/fmt/format.h | 17 ++++++++++++++++-
 test/format-test.cc  |  9 +++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/include/fmt/format.h b/include/fmt/format.h
index b11abdc3..26b81e07 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -3526,6 +3526,13 @@ inline OutputIt vformat_to(OutputIt out, string_view format_str,
   typedef output_range<OutputIt, char> range;
   return vformat_to<arg_formatter<range>>(range(out), format_str, args);
 }
+template <typename OutputIt, typename... Args>
+inline OutputIt vformat_to(
+    OutputIt out, wstring_view format_str,
+    typename format_args_t<OutputIt, wchar_t>::type args) {
+  typedef output_range<OutputIt, wchar_t> range;
+  return vformat_to<arg_formatter<range>>(range(out), format_str, args);
+}
 
 /**
  \rst
@@ -3578,12 +3585,20 @@ struct format_to_n_result {
  */
 template <typename OutputIt, typename... Args>
 inline format_to_n_result<OutputIt> format_to_n(
-    OutputIt out, std::size_t n, string_view format_str, const Args & ... args) {
+    OutputIt out, std::size_t n, string_view format_str, const Args &... args) {
   typedef internal::truncating_iterator<OutputIt> It;
   auto it = vformat_to(It(out, n), format_str,
       make_format_args<typename format_context_t<It>::type>(args...));
   return {it.base(), it.count()};
 }
+template <typename OutputIt, typename... Args>
+inline format_to_n_result<OutputIt> format_to_n(
+    OutputIt out, std::size_t n, wstring_view format_str, const Args &... args) {
+  typedef internal::truncating_iterator<OutputIt> It;
+  auto it = vformat_to(It(out, n), format_str,
+      make_format_args<typename format_context_t<It, wchar_t>::type>(args...));
+  return {it.base(), it.count()};
+}
 
 inline std::string vformat(string_view format_str, format_args args) {
   memory_buffer buffer;
diff --git a/test/format-test.cc b/test/format-test.cc
index e0cddd14..5af837da 100644
--- a/test/format-test.cc
+++ b/test/format-test.cc
@@ -1525,6 +1525,15 @@ TEST(FormatTest, FormatToN) {
   EXPECT_EQ("foox", fmt::string_view(buffer, 4));
 }
 
+TEST(FormatTest, WideFormatToN) {
+  wchar_t buffer[4];
+  buffer[3] = L'x';
+  auto result = fmt::format_to_n(buffer, 3, L"{}", 12345);
+  EXPECT_EQ(5u, result.size);
+  EXPECT_EQ(buffer + 3, result.out);
+  EXPECT_EQ(L"123x", fmt::wstring_view(buffer, 4));
+}
+
 #if FMT_USE_CONSTEXPR
 struct test_arg_id_handler {
   enum result { NONE, EMPTY, INDEX, NAME, ERROR };