ladybird/Userland/Libraries/LibUnicode/DateTimeFormat.cpp
Timothy Flynn 48ce72e472 LibUnicode: Parse and generate regional hour cycles
Unlike most data in the CLDR, hour cycles are not stored on a per-locale
basis. Instead, they are keyed by a string that is usually a region, but
sometimes is a locale. Therefore, given a locale, to determine the hour
cycles for that locale, we:

    1. Check if the locale itself is assigned hour cycles.
    2. If the locale has a region, check if that region is assigned hour
       cycles.
    3. Otherwise, maximize that locale, and if the maximized locale has
       a region, check if that region is assigned hour cycles.
    4. If the above all fail, fallback to the "001" region.

Further, each locale's default hour cycle is the first assigned hour
cycle.
2021-11-29 22:48:46 +00:00

143 lines
4 KiB
C++

/*
* Copyright (c) 2021, Tim Flynn <trflynn89@pm.me>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibUnicode/DateTimeFormat.h>
#include <LibUnicode/Locale.h>
#if ENABLE_UNICODE_DATA
# include <LibUnicode/UnicodeDateTimeFormat.h>
#endif
namespace Unicode {
HourCycle hour_cycle_from_string(StringView hour_cycle)
{
if (hour_cycle == "h11"sv)
return Unicode::HourCycle::H11;
else if (hour_cycle == "h12"sv)
return Unicode::HourCycle::H12;
else if (hour_cycle == "h23"sv)
return Unicode::HourCycle::H23;
else if (hour_cycle == "h24"sv)
return Unicode::HourCycle::H24;
VERIFY_NOT_REACHED();
}
StringView hour_cycle_to_string(HourCycle hour_cycle)
{
switch (hour_cycle) {
case HourCycle::H11:
return "h11"sv;
case HourCycle::H12:
return "h12"sv;
case HourCycle::H23:
return "h23"sv;
case HourCycle::H24:
return "h24"sv;
default:
VERIFY_NOT_REACHED();
}
}
CalendarPatternStyle calendar_pattern_style_from_string(StringView style)
{
if (style == "narrow"sv)
return CalendarPatternStyle::Narrow;
if (style == "short"sv)
return CalendarPatternStyle::Short;
if (style == "long"sv)
return CalendarPatternStyle::Long;
if (style == "numeric"sv)
return CalendarPatternStyle::Numeric;
if (style == "2-digit"sv)
return CalendarPatternStyle::TwoDigit;
VERIFY_NOT_REACHED();
}
StringView calendar_pattern_style_to_string(CalendarPatternStyle style)
{
switch (style) {
case CalendarPatternStyle::Narrow:
return "narrow"sv;
case CalendarPatternStyle::Short:
return "short"sv;
case CalendarPatternStyle::Long:
return "long"sv;
case CalendarPatternStyle::Numeric:
return "Numeric"sv;
case CalendarPatternStyle::TwoDigit:
return "2-digit"sv;
default:
VERIFY_NOT_REACHED();
}
}
// https://unicode.org/reports/tr35/tr35-dates.html#Date_Field_Symbol_Table
Vector<Unicode::HourCycle> get_regional_hour_cycles([[maybe_unused]] StringView locale)
{
#if ENABLE_UNICODE_DATA
if (auto hour_cycles = Detail::get_regional_hour_cycles(locale); !hour_cycles.is_empty())
return hour_cycles;
auto return_default_hour_cycles = []() {
auto hour_cycles = Detail::get_regional_hour_cycles("001"sv);
VERIFY(!hour_cycles.is_empty());
return hour_cycles;
};
auto language = parse_unicode_language_id(locale);
if (!language.has_value())
return return_default_hour_cycles();
if (!language->region.has_value())
language = add_likely_subtags(*language);
if (!language.has_value() || !language->region.has_value())
return return_default_hour_cycles();
if (auto hour_cycles = Detail::get_regional_hour_cycles(*language->region); !hour_cycles.is_empty())
return hour_cycles;
return return_default_hour_cycles();
#else
return {};
#endif
}
Optional<Unicode::HourCycle> get_default_regional_hour_cycle(StringView locale)
{
if (auto hour_cycles = get_regional_hour_cycles(locale); !hour_cycles.is_empty())
return hour_cycles.first();
return {};
}
Optional<CalendarFormat> get_calendar_format([[maybe_unused]] StringView locale, [[maybe_unused]] StringView calendar, [[maybe_unused]] CalendarFormatType type)
{
#if ENABLE_UNICODE_DATA
switch (type) {
case CalendarFormatType::Date:
return Detail::get_calendar_date_format(locale, calendar);
case CalendarFormatType::Time:
return Detail::get_calendar_time_format(locale, calendar);
case CalendarFormatType::DateTime:
return Detail::get_calendar_date_time_format(locale, calendar);
default:
VERIFY_NOT_REACHED();
}
#else
return {};
#endif
}
Vector<CalendarPattern> get_calendar_available_formats([[maybe_unused]] StringView locale, [[maybe_unused]] StringView calendar)
{
#if ENABLE_UNICODE_DATA
return Detail::get_calendar_available_formats(locale, calendar);
#else
return {};
#endif
}
}