// Formatting library for C++ - optional wchar_t and exotic character support
//
// Copyright (c) 2012 - present, Victor Zverovich
// All rights reserved.
// For the license information refer to format.h.
#ifndef FMT_XCHAR_H_
#define FMT_XCHAR_H_
#include <cwchar>
#include "format.h"
#ifndef FMT_STATIC_THOUSANDS_SEPARATOR
# include <locale>
#endif
FMT_BEGIN_NAMESPACE
namespace detail {
template <typename T>
using is_exotic_char = bool_constant<!std::is_same<T, char>::value>;
inline auto write_loc(std::back_insert_iterator<detail::buffer<wchar_t>> out,
loc_value value, const format_specs<wchar_t>& specs,
locale_ref loc) -> bool {
auto& numpunct =
std::use_facet<std::numpunct<wchar_t>>(loc.get<std::locale>());
auto separator = std::wstring();
auto grouping = numpunct.grouping();
if (!grouping.empty()) separator = std::wstring(1, numpunct.thousands_sep());
return value.visit(loc_writer<wchar_t>{out, specs, separator, grouping, {}});
return false;
}
} // namespace detail
FMT_BEGIN_EXPORT
using wstring_view = basic_string_view<wchar_t>;
using wformat_parse_context = basic_format_parse_context<wchar_t>;
using wformat_context = buffer_context<wchar_t>;
using wformat_args = basic_format_args<wformat_context>;
using wmemory_buffer = basic_memory_buffer<wchar_t>;
#if FMT_GCC_VERSION && FMT_GCC_VERSION < 409
// Workaround broken conversion on older gcc.
template <typename... Args> using wformat_string = wstring_view;
inline auto runtime(wstring_view s) -> wstring_view { return s; }
#else
template <typename... Args>
using wformat_string = basic_format_string<wchar_t, type_identity_t<Args>...>;
inline auto runtime(wstring_view s) -> runtime_format_string<wchar_t> {
return {{s}};
template <> struct is_char<wchar_t> : std::true_type {};
template <> struct is_char<detail::char8_type> : std::true_type {};
template <> struct is_char<char16_t> : std::true_type {};
template <> struct is_char<char32_t> : std::true_type {};
template <typename... T>
constexpr format_arg_store<wformat_context, T...> make_wformat_args(
const T&... args) {
return {args...};
inline namespace literals {
#if FMT_USE_USER_DEFINED_LITERALS && !FMT_USE_NONTYPE_TEMPLATE_ARGS
constexpr detail::udl_arg<wchar_t> operator"" _a(const wchar_t* s, size_t) {
return {s};
} // namespace literals
template <typename It, typename Sentinel>
auto join(It begin, Sentinel end, wstring_view sep)
-> join_view<It, Sentinel, wchar_t> {
return {begin, end, sep};
template <typename Range>
auto join(Range&& range, wstring_view sep)
-> join_view<detail::iterator_t<Range>, detail::sentinel_t<Range>,
wchar_t> {
return join(std::begin(range), std::end(range), sep);
auto join(std::initializer_list<T> list, wstring_view sep)
-> join_view<const T*, const T*, wchar_t> {
return join(std::begin(list), std::end(list), sep);
template <typename Char, FMT_ENABLE_IF(!std::is_same<Char, char>::value)>
auto vformat(basic_string_view<Char> format_str,
basic_format_args<buffer_context<type_identity_t<Char>>> args)
-> std::basic_string<Char> {
auto buf = basic_memory_buffer<Char>();
detail::vformat_to(buf, format_str, args);
return to_string(buf);
auto format(wformat_string<T...> fmt, T&&... args) -> std::wstring {
return vformat(fmt::wstring_view(fmt), fmt::make_wformat_args(args...));
// Pass char_t as a default template parameter instead of using
// std::basic_string<char_t<S>> to reduce the symbol size.
template <typename S, typename... T, typename Char = char_t<S>,
FMT_ENABLE_IF(!std::is_same<Char, char>::value &&
!std::is_same<Char, wchar_t>::value)>
auto format(const S& format_str, T&&... args) -> std::basic_string<Char> {
return vformat(detail::to_string_view(format_str),
fmt::make_format_args<buffer_context<Char>>(args...));
template <typename Locale, typename S, typename Char = char_t<S>,
FMT_ENABLE_IF(detail::is_locale<Locale>::value&&
detail::is_exotic_char<Char>::value)>
inline auto vformat(
const Locale& loc, const S& format_str,
return detail::vformat(loc, detail::to_string_view(format_str), args);
template <typename Locale, typename S, typename... T, typename Char = char_t<S>,
inline auto format(const Locale& loc, const S& format_str, T&&... args)
return detail::vformat(loc, detail::to_string_view(format_str),
template <typename OutputIt, typename S, typename Char = char_t<S>,
FMT_ENABLE_IF(detail::is_output_iterator<OutputIt, Char>::value&&
auto vformat_to(OutputIt out, const S& format_str,
-> OutputIt {
auto&& buf = detail::get_buffer<Char>(out);
detail::vformat_to(buf, detail::to_string_view(format_str), args);
return detail::get_iterator(buf, out);
template <typename OutputIt, typename S, typename... T,
typename Char = char_t<S>,
inline auto format_to(OutputIt out, const S& fmt, T&&... args) -> OutputIt {
return vformat_to(out, detail::to_string_view(fmt),
template <typename Locale, typename S, typename OutputIt, typename... Args,
detail::is_locale<Locale>::value&&
inline auto vformat_to(
OutputIt out, const Locale& loc, const S& format_str,
basic_format_args<buffer_context<type_identity_t<Char>>> args) -> OutputIt {
vformat_to(buf, detail::to_string_view(format_str), args,
detail::locale_ref(loc));
template <
typename OutputIt, typename Locale, typename S, typename... T,
bool enable = detail::is_output_iterator<OutputIt, Char>::value&&
detail::is_locale<Locale>::value&& detail::is_exotic_char<Char>::value>
inline auto format_to(OutputIt out, const Locale& loc, const S& format_str,
T&&... args) ->
typename std::enable_if<enable, OutputIt>::type {
return vformat_to(out, loc, detail::to_string_view(format_str),
template <typename OutputIt, typename Char, typename... Args,
inline auto vformat_to_n(
OutputIt out, size_t n, basic_string_view<Char> format_str,
-> format_to_n_result<OutputIt> {
using traits = detail::fixed_buffer_traits;
auto buf = detail::iterator_buffer<OutputIt, Char, traits>(out, n);
return {buf.out(), buf.count()};
inline auto format_to_n(OutputIt out, size_t n, const S& fmt, T&&... args)
return vformat_to_n(out, n, detail::to_string_view(fmt),
FMT_ENABLE_IF(detail::is_exotic_char<Char>::value)>
inline auto formatted_size(const S& fmt, T&&... args) -> size_t {
auto buf = detail::counting_buffer<Char>();
detail::vformat_to(buf, detail::to_string_view(fmt),
return buf.count();
inline void vprint(std::FILE* f, wstring_view fmt, wformat_args args) {
auto buf = wmemory_buffer();
detail::vformat_to(buf, fmt, args);
buf.push_back(L'\0');
if (std::fputws(buf.data(), f) == -1)
FMT_THROW(system_error(errno, FMT_STRING("cannot write to file")));
inline void vprint(wstring_view fmt, wformat_args args) {
vprint(stdout, fmt, args);
void print(std::FILE* f, wformat_string<T...> fmt, T&&... args) {
return vprint(f, wstring_view(fmt), fmt::make_wformat_args(args...));
template <typename... T> void print(wformat_string<T...> fmt, T&&... args) {
return vprint(wstring_view(fmt), fmt::make_wformat_args(args...));
void println(std::FILE* f, wformat_string<T...> fmt, T&&... args) {
return print(f, L"{}\n", fmt::format(fmt, std::forward<T>(args)...));
template <typename... T> void println(wformat_string<T...> fmt, T&&... args) {
return print(L"{}\n", fmt::format(fmt, std::forward<T>(args)...));
/**
Converts *value* to ``std::wstring`` using the default format for type *T*.
*/
template <typename T> inline auto to_wstring(const T& value) -> std::wstring {
return format(FMT_STRING(L"{}"), value);
FMT_END_EXPORT
FMT_END_NAMESPACE
#endif // FMT_XCHAR_H_