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Refactor chrono formatting

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This commit is contained in:
Victor Zverovich 2021-05-24 15:30:59 -07:00
parent 883d9595c5
commit b955e7a6b2
1 changed files with 47 additions and 48 deletions
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95
include/fmt/chrono.h
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@ -287,6 +287,45 @@ inline null<> localtime_r FMT_NOMACRO(...) { return null<>(); }
inline null<> localtime_s(...) { return null<>(); }
inline null<> gmtime_r(...) { return null<>(); }
inline null<> gmtime_s(...) { return null<>(); }
template <typename OutputIt>
OutputIt write(OutputIt out, const std::tm& time, const std::locale& loc,
char format, char modifier = 0) {
auto&& os = std::ostringstream();
using iterator = std::ostreambuf_iterator<char>;
const auto& facet = std::use_facet<std::time_put<char, iterator>>(loc);
auto end = facet.put(os, os, ' ', &time, format, modifier);
if (end.failed()) FMT_THROW(format_error("failed to format time"));
auto str = os.str();
if (detail::is_utf8() && loc != std::locale::classic()) {
// char16_t and char32_t codecvts are broken in MSVC (linkage errors).
using code_unit = conditional_t<FMT_MSC_VER, wchar_t, char16_t>;
auto& f =
std::use_facet<std::codecvt<code_unit, char, std::mbstate_t>>(loc);
auto mb = std::mbstate_t();
const char* from_next = nullptr;
code_unit* to_next = nullptr;
constexpr size_t buf_size = 32;
code_unit buf[buf_size] = {};
auto result = f.in(mb, str.data(), str.data() + str.size(), from_next, buf,
buf + buf_size, to_next);
if (result != std::codecvt_base::ok)
FMT_THROW(format_error("failed to format time"));
str.clear();
for (code_unit* p = buf; p != to_next; ++p) {
code_unit c = *p;
if (c < 0x80) {
str.push_back(static_cast<char>(c));
} else if (c < 0x800) {
str.push_back(static_cast<char>(0xc0 | (c >> 6)));
str.push_back(static_cast<char>(0x80 | (c & 0x3f)));
} else {
FMT_THROW(format_error("failed to format time"));
}
}
}
return std::copy(str.begin(), str.end(), out);
}
} // namespace detail
FMT_MODULE_EXPORT_BEGIN
@ -973,14 +1012,9 @@ struct chrono_formatter {
void format_localized(const tm& time, char format, char modifier = 0) {
if (isnan(val)) return write_nan();
auto locale = localized ? context.locale().template get<std::locale>()
: std::locale::classic();
auto& facet = std::use_facet<std::time_put<char_type>>(locale);
std::basic_ostringstream<char_type> os;
os.imbue(locale);
facet.put(os, os, ' ', &time, format, modifier);
auto str = os.str();
std::copy(str.begin(), str.end(), out);
const auto& loc = localized ? context.locale().template get<std::locale>()
: std::locale::classic();
out = detail::write(out, time, loc, format, modifier);
}
void on_text(const char_type* begin, const char_type* end) {
@ -1128,46 +1162,11 @@ template <> struct formatter<weekday> {
}
auto format(weekday wd, format_context& ctx) -> decltype(ctx.out()) {
auto tm = std::tm();
tm.tm_wday = static_cast<int>(wd.c_encoding());
auto&& os = std::ostringstream();
using iterator = std::ostreambuf_iterator<char>;
auto& loc = localized ? ctx.locale().template get<std::locale>()
: std::locale::classic();
const auto& tp = std::use_facet<std::time_put<char, iterator>>(loc);
auto fmt = string_view("%a");
auto end =
tp.put(iterator(os.rdbuf()), os, ' ', &tm, fmt.begin(), fmt.end());
if (end.failed()) FMT_THROW(format_error("failed to format time"));
auto s = os.str();
if (detail::is_utf8() && localized) {
// char16_t and char32_t codecvts are broken in MSVC (linkage errors).
using code_unit = conditional_t<FMT_MSC_VER, wchar_t, char16_t>;
auto& f =
std::use_facet<std::codecvt<code_unit, char, std::mbstate_t>>(loc);
auto mb = std::mbstate_t();
const char* from_next = nullptr;
code_unit* to_next = nullptr;
constexpr size_t buf_size = 100;
code_unit buf[buf_size] = {};
auto result = f.in(mb, s.data(), s.data() + s.size(), from_next, buf,
buf + buf_size, to_next);
if (result != std::codecvt_base::ok)
FMT_THROW(format_error("failed to format time"));
s.clear();
for (code_unit* p = buf; p != to_next; ++p) {
code_unit c = *p;
if (c < 0x80) {
s.push_back(static_cast<char>(c));
} else if (c < 0x800) {
s.push_back(static_cast<char>(0xc0 | (c >> 6)));
s.push_back(static_cast<char>(0x80 | (c & 0x3f)));
} else {
FMT_THROW(format_error("failed to format time"));
}
}
}
return std::copy(s.begin(), s.end(), ctx.out());
auto time = std::tm();
time.tm_wday = static_cast<int>(wd.c_encoding());
const auto& loc = localized ? ctx.locale().template get<std::locale>()
: std::locale::classic();
return detail::write(ctx.out(), time, loc, 'a');
}
};