/src/serenity/Userland/Libraries/LibLocale/DateTimeFormat.cpp

Source
/*
 * Copyright (c) 2021-2023, Tim Flynn <trflynn89@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include <AK/Array.h>
#include <AK/StringBuilder.h>
#include <LibLocale/DateTimeFormat.h>
#include <LibLocale/Locale.h>
#include <LibLocale/NumberFormat.h>
#include <stdlib.h>

namespace Locale {

HourCycle hour_cycle_from_string(StringView hour_cycle)
{
    if (hour_cycle == "h11"sv)
        return HourCycle::H11;
    if (hour_cycle == "h12"sv)
        return HourCycle::H12;
    if (hour_cycle == "h23"sv)
        return HourCycle::H23;
    if (hour_cycle == "h24"sv)
        return 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;
    if (style == "shortOffset"sv)
        return CalendarPatternStyle::ShortOffset;
    if (style == "longOffset"sv)
        return CalendarPatternStyle::LongOffset;
    if (style == "shortGeneric"sv)
        return CalendarPatternStyle::ShortGeneric;
    if (style == "longGeneric"sv)
        return CalendarPatternStyle::LongGeneric;
    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;
    case CalendarPatternStyle::ShortOffset:
        return "shortOffset"sv;
    case CalendarPatternStyle::LongOffset:
        return "longOffset"sv;
    case CalendarPatternStyle::ShortGeneric:
        return "shortGeneric"sv;
    case CalendarPatternStyle::LongGeneric:
        return "longGeneric"sv;
    default:
        VERIFY_NOT_REACHED();
    }
}

Optional<HourCycleRegion> __attribute__((weak)) hour_cycle_region_from_string(StringView) { return {}; }
Vector<HourCycle> __attribute__((weak)) get_regional_hour_cycles(StringView) { return {}; }

template<typename T, typename GetRegionalValues>
static T find_regional_values_for_locale(StringView locale, GetRegionalValues&& get_regional_values)
{
    auto has_value = [](auto const& container) {
        if constexpr (requires { container.has_value(); })
            return container.has_value();
        else
            return !container.is_empty();
    };

    if (auto regional_values = get_regional_values(locale); has_value(regional_values))
        return regional_values;

    auto return_default_values = [&]() { return get_regional_values("001"sv); };

    auto language = parse_unicode_language_id(locale);
    if (!language.has_value())
        return return_default_values();

    if (!language->region.has_value())
        language = add_likely_subtags(*language);
    if (!language.has_value() || !language->region.has_value())
        return return_default_values();

    if (auto regional_values = get_regional_values(*language->region); has_value(regional_values))
        return regional_values;

    return return_default_values();
}

// https://unicode.org/reports/tr35/tr35-dates.html#Date_Field_Symbol_Table
Vector<HourCycle> get_locale_hour_cycles(StringView locale)
{
    return find_regional_values_for_locale<Vector<HourCycle>>(locale, get_regional_hour_cycles);
}

Optional<HourCycle> get_default_regional_hour_cycle(StringView locale)
{
    if (auto hour_cycles = get_locale_hour_cycles(locale); !hour_cycles.is_empty())
        return hour_cycles.first();
    return {};
}

Optional<MinimumDaysRegion> __attribute__((weak)) minimum_days_region_from_string(StringView) { return {}; }
Optional<u8> __attribute__((weak)) get_regional_minimum_days(StringView) { return {}; }

Optional<u8> get_locale_minimum_days(StringView locale)
{
    return find_regional_values_for_locale<Optional<u8>>(locale, get_regional_minimum_days);
}

Optional<FirstDayRegion> __attribute__((weak)) first_day_region_from_string(StringView) { return {}; }
Optional<Weekday> __attribute__((weak)) get_regional_first_day(StringView) { return {}; }

Optional<Weekday> get_locale_first_day(StringView locale)
{
    return find_regional_values_for_locale<Optional<Weekday>>(locale, get_regional_first_day);
}

Optional<WeekendStartRegion> __attribute__((weak)) weekend_start_region_from_string(StringView) { return {}; }
Optional<Weekday> __attribute__((weak)) get_regional_weekend_start(StringView) { return {}; }

Optional<Weekday> get_locale_weekend_start(StringView locale)
{
    return find_regional_values_for_locale<Optional<Weekday>>(locale, get_regional_weekend_start);
}

Optional<WeekendEndRegion> __attribute__((weak)) weekend_end_region_from_string(StringView) { return {}; }
Optional<Weekday> __attribute__((weak)) get_regional_weekend_end(StringView) { return {}; }

Optional<Weekday> get_locale_weekend_end(StringView locale)
{
    return find_regional_values_for_locale<Optional<Weekday>>(locale, get_regional_weekend_end);
}

String combine_skeletons(StringView first, StringView second)
{
    // https://unicode.org/reports/tr35/tr35-dates.html#availableFormats_appendItems
    constexpr auto field_order = Array {
        "G"sv,       // Era
        "yYuUr"sv,   // Year
        "ML"sv,      // Month
        "dDFg"sv,    // Day
        "Eec"sv,     // Weekday
        "abB"sv,     // Period
        "hHKk"sv,    // Hour
        "m"sv,       // Minute
        "sSA"sv,     // Second
        "zZOvVXx"sv, // Zone
    };

    StringBuilder builder;

    auto append_from_skeleton = [&](auto skeleton, auto ch) {
        auto first_index = skeleton.find(ch);
        if (!first_index.has_value())
            return false;

        auto last_index = skeleton.find_last(ch);

        builder.append(skeleton.substring_view(*first_index, *last_index - *first_index + 1));
        return true;
    };

    for (auto fields : field_order) {
        for (auto ch : fields) {
            if (append_from_skeleton(first, ch))
                break;
            if (append_from_skeleton(second, ch))
                break;
        }
    }

    return MUST(builder.to_string());
}

Optional<CalendarFormat> __attribute__((weak)) get_calendar_date_format(StringView, StringView) { return {}; }
Optional<CalendarFormat> __attribute__((weak)) get_calendar_time_format(StringView, StringView) { return {}; }
Optional<CalendarFormat> __attribute__((weak)) get_calendar_date_time_format(StringView, StringView) { return {}; }

Optional<CalendarFormat> get_calendar_format(StringView locale, StringView calendar, CalendarFormatType type)
{
    switch (type) {
    case CalendarFormatType::Date:
        return get_calendar_date_format(locale, calendar);
    case CalendarFormatType::Time:
        return get_calendar_time_format(locale, calendar);
    case CalendarFormatType::DateTime:
        return get_calendar_date_time_format(locale, calendar);
    default:
        VERIFY_NOT_REACHED();
    }
}

Vector<CalendarPattern> __attribute__((weak)) get_calendar_available_formats(StringView, StringView) { return {}; }
Optional<CalendarRangePattern> __attribute__((weak)) get_calendar_default_range_format(StringView, StringView) { return {}; }
Vector<CalendarRangePattern> __attribute__((weak)) get_calendar_range_formats(StringView, StringView, StringView) { return {}; }
Vector<CalendarRangePattern> __attribute__((weak)) get_calendar_range12_formats(StringView, StringView, StringView) { return {}; }
Optional<StringView> __attribute__((weak)) get_calendar_era_symbol(StringView, StringView, CalendarPatternStyle, Era) { return {}; }
Optional<StringView> __attribute__((weak)) get_calendar_month_symbol(StringView, StringView, CalendarPatternStyle, Month) { return {}; }
Optional<StringView> __attribute__((weak)) get_calendar_weekday_symbol(StringView, StringView, CalendarPatternStyle, Weekday) { return {}; }
Optional<StringView> __attribute__((weak)) get_calendar_day_period_symbol(StringView, StringView, CalendarPatternStyle, DayPeriod) { return {}; }
Optional<StringView> __attribute__((weak)) get_calendar_day_period_symbol_for_hour(StringView, StringView, CalendarPatternStyle, u8) { return {}; }

Optional<StringView> __attribute__((weak)) get_time_zone_name(StringView, StringView, CalendarPatternStyle, TimeZone::InDST) { return {}; }
Optional<TimeZoneFormat> __attribute__((weak)) get_time_zone_format(StringView) { return {}; }

static Optional<String> format_time_zone_offset(StringView locale, CalendarPatternStyle style, i64 offset_seconds)
{
    auto formats = get_time_zone_format(locale);
    if (!formats.has_value())
        return {};

    auto number_system = get_preferred_keyword_value_for_locale(locale, "nu"sv);
    if (!number_system.has_value())
        return {};

    if (offset_seconds == 0)
        return MUST(String::from_utf8(formats->gmt_zero_format));

    auto sign = offset_seconds > 0 ? formats->symbol_ahead_sign : formats->symbol_behind_sign;
    auto separator = offset_seconds > 0 ? formats->symbol_ahead_separator : formats->symbol_behind_separator;
    offset_seconds = llabs(offset_seconds);

    auto offset_hours = offset_seconds / 3'600;
    offset_seconds %= 3'600;

    auto offset_minutes = offset_seconds / 60;
    offset_seconds %= 60;

    StringBuilder builder;
    builder.append(sign);

    switch (style) {
    // The long format always uses 2-digit hours field and minutes field, with optional 2-digit seconds field.
    case CalendarPatternStyle::LongOffset:
        builder.appendff("{:02}{}{:02}", offset_hours, separator, offset_minutes);
        if (offset_seconds > 0)
            builder.appendff("{}{:02}", separator, offset_seconds);
        break;

    // The short format is intended for the shortest representation and uses hour fields without leading zero, with optional 2-digit minutes and seconds fields.
    case CalendarPatternStyle::ShortOffset:
        builder.appendff("{}", offset_hours);
        if (offset_minutes > 0) {
            builder.appendff("{}{:02}", separator, offset_minutes);
            if (offset_seconds > 0)
                builder.appendff("{}{:02}", separator, offset_seconds);
        }
        break;

    default:
        VERIFY_NOT_REACHED();
    }

    // The digits used for hours, minutes and seconds fields in this format are the locale's default decimal digits.
    auto result = replace_digits_for_number_system(*number_system, builder.string_view());
    return MUST(MUST(String::from_utf8(formats->gmt_format)).replace("{0}"sv, result, ReplaceMode::FirstOnly));
}

// https://unicode.org/reports/tr35/tr35-dates.html#Time_Zone_Format_Terminology
String format_time_zone(StringView locale, StringView time_zone, CalendarPatternStyle style, AK::UnixDateTime time)
{
    auto offset = TimeZone::get_time_zone_offset(time_zone, time);
    if (!offset.has_value())
        return MUST(String::from_utf8(time_zone));

    switch (style) {
    case CalendarPatternStyle::Short:
    case CalendarPatternStyle::Long:
    case CalendarPatternStyle::ShortGeneric:
    case CalendarPatternStyle::LongGeneric:
        if (auto name = get_time_zone_name(locale, time_zone, style, offset->in_dst); name.has_value())
            return MUST(String::from_utf8(*name));
        break;

    case CalendarPatternStyle::ShortOffset:
    case CalendarPatternStyle::LongOffset:
        if (auto formatted_offset = format_time_zone_offset(locale, style, offset->seconds); formatted_offset.has_value())
            return formatted_offset.release_value();
        return MUST(String::from_utf8(time_zone));

    default:
        VERIFY_NOT_REACHED();
    }

    // If more styles are added, consult the following table to ensure always falling back to GMT offset is still correct:
    // https://unicode.org/reports/tr35/tr35-dates.html#dfst-zone
    switch (style) {
    case CalendarPatternStyle::Short:
    case CalendarPatternStyle::ShortGeneric:
        return format_time_zone(locale, time_zone, CalendarPatternStyle::ShortOffset, time);

    case CalendarPatternStyle::Long:
    case CalendarPatternStyle::LongGeneric:
        return format_time_zone(locale, time_zone, CalendarPatternStyle::LongOffset, time);

    default:
        VERIFY_NOT_REACHED();
    }
}

}

Coverage Report

Created: 2025-12-18 07:52

Line	Count	Source
1		/*
2		* Copyright (c) 2021-2023, Tim Flynn <trflynn89@serenityos.org>
3		*
4		* SPDX-License-Identifier: BSD-2-Clause
5		*/
6
7		#include <AK/Array.h>
8		#include <AK/StringBuilder.h>
9		#include <LibLocale/DateTimeFormat.h>
10		#include <LibLocale/Locale.h>
11		#include <LibLocale/NumberFormat.h>
12		#include <stdlib.h>
13
14		namespace Locale {
15
16		HourCycle hour_cycle_from_string(StringView hour_cycle)
17	0	{
18	0	if (hour_cycle == "h11"sv)
19	0	return HourCycle::H11;
20	0	if (hour_cycle == "h12"sv)
21	0	return HourCycle::H12;
22	0	if (hour_cycle == "h23"sv)
23	0	return HourCycle::H23;
24	0	if (hour_cycle == "h24"sv)
25	0	return HourCycle::H24;
26	0	VERIFY_NOT_REACHED();
27	0	}
28
29		StringView hour_cycle_to_string(HourCycle hour_cycle)
30	0	{
31	0	switch (hour_cycle) {
32	0	case HourCycle::H11:
33	0	return "h11"sv;
34	0	case HourCycle::H12:
35	0	return "h12"sv;
36	0	case HourCycle::H23:
37	0	return "h23"sv;
38	0	case HourCycle::H24:
39	0	return "h24"sv;
40	0	default:
41	0	VERIFY_NOT_REACHED();
42	0	}
43	0	}
44
45		CalendarPatternStyle calendar_pattern_style_from_string(StringView style)
46	0	{
47	0	if (style == "narrow"sv)
48	0	return CalendarPatternStyle::Narrow;
49	0	if (style == "short"sv)
50	0	return CalendarPatternStyle::Short;
51	0	if (style == "long"sv)
52	0	return CalendarPatternStyle::Long;
53	0	if (style == "numeric"sv)
54	0	return CalendarPatternStyle::Numeric;
55	0	if (style == "2-digit"sv)
56	0	return CalendarPatternStyle::TwoDigit;
57	0	if (style == "shortOffset"sv)
58	0	return CalendarPatternStyle::ShortOffset;
59	0	if (style == "longOffset"sv)
60	0	return CalendarPatternStyle::LongOffset;
61	0	if (style == "shortGeneric"sv)
62	0	return CalendarPatternStyle::ShortGeneric;
63	0	if (style == "longGeneric"sv)
64	0	return CalendarPatternStyle::LongGeneric;
65	0	VERIFY_NOT_REACHED();
66	0	}
67
68		StringView calendar_pattern_style_to_string(CalendarPatternStyle style)
69	0	{
70	0	switch (style) {
71	0	case CalendarPatternStyle::Narrow:
72	0	return "narrow"sv;
73	0	case CalendarPatternStyle::Short:
74	0	return "short"sv;
75	0	case CalendarPatternStyle::Long:
76	0	return "long"sv;
77	0	case CalendarPatternStyle::Numeric:
78	0	return "numeric"sv;
79	0	case CalendarPatternStyle::TwoDigit:
80	0	return "2-digit"sv;
81	0	case CalendarPatternStyle::ShortOffset:
82	0	return "shortOffset"sv;
83	0	case CalendarPatternStyle::LongOffset:
84	0	return "longOffset"sv;
85	0	case CalendarPatternStyle::ShortGeneric:
86	0	return "shortGeneric"sv;
87	0	case CalendarPatternStyle::LongGeneric:
88	0	return "longGeneric"sv;
89	0	default:
90	0	VERIFY_NOT_REACHED();
91	0	}
92	0	}
93
94		Optional<HourCycleRegion> __attribute__((weak)) hour_cycle_region_from_string(StringView) { return {}; }
95		Vector<HourCycle> __attribute__((weak)) get_regional_hour_cycles(StringView) { return {}; }
96
97		template<typename T, typename GetRegionalValues>
98		static T find_regional_values_for_locale(StringView locale, GetRegionalValues&& get_regional_values)
99	0	{
100	0	auto has_value = [](auto const& container) {
101		if constexpr (requires { container.has_value(); })
102	0	return container.has_value();
103		else
104	0	return !container.is_empty();
105	0	}; Unexecuted instantiation: DateTimeFormat.cpp:auto Locale::find_regional_values_for_locale<AK::Vector<Locale::HourCycle, 0ul>, AK::Vector<Locale::HourCycle, 0ul> (&)(AK::StringView)>(AK::StringView, AK::Vector<Locale::HourCycle, 0ul> (&)(AK::StringView))::{lambda(auto:1 const&)#1}::operator()<AK::Vector<Locale::HourCycle, 0ul> >(AK::Vector<Locale::HourCycle, 0ul> const&) const Unexecuted instantiation: DateTimeFormat.cpp:auto Locale::find_regional_values_for_locale<AK::Optional<unsigned char>, AK::Optional<unsigned char> (&)(AK::StringView)>(AK::StringView, AK::Optional<unsigned char> (&)(AK::StringView))::{lambda(auto:1 const&)#1}::operator()<AK::Optional<unsigned char> >(AK::Optional<unsigned char> const&) const Unexecuted instantiation: DateTimeFormat.cpp:auto Locale::find_regional_values_for_locale<AK::Optional<Locale::Weekday>, AK::Optional<Locale::Weekday> (&)(AK::StringView)>(AK::StringView, AK::Optional<Locale::Weekday> (&)(AK::StringView))::{lambda(auto:1 const&)#1}::operator()<AK::Optional<Locale::Weekday> >(AK::Optional<Locale::Weekday> const&) const
106
107	0	if (auto regional_values = get_regional_values(locale); has_value(regional_values))
108	0	return regional_values;
109
110	0	auto return_default_values = [&]() { return get_regional_values("001"sv); }; Unexecuted instantiation: DateTimeFormat.cpp:Locale::find_regional_values_for_locale<AK::Vector<Locale::HourCycle, 0ul>, AK::Vector<Locale::HourCycle, 0ul> (&)(AK::StringView)>(AK::StringView, AK::Vector<Locale::HourCycle, 0ul> (&)(AK::StringView))::{lambda()#1}::operator()() const Unexecuted instantiation: DateTimeFormat.cpp:Locale::find_regional_values_for_locale<AK::Optional<unsigned char>, AK::Optional<unsigned char> (&)(AK::StringView)>(AK::StringView, AK::Optional<unsigned char> (&)(AK::StringView))::{lambda()#1}::operator()() const Unexecuted instantiation: DateTimeFormat.cpp:Locale::find_regional_values_for_locale<AK::Optional<Locale::Weekday>, AK::Optional<Locale::Weekday> (&)(AK::StringView)>(AK::StringView, AK::Optional<Locale::Weekday> (&)(AK::StringView))::{lambda()#1}::operator()() const
111
112	0	auto language = parse_unicode_language_id(locale);
113	0	if (!language.has_value())
114	0	return return_default_values();
115
116	0	if (!language->region.has_value())
117	0	language = add_likely_subtags(*language);
118	0	if (!language.has_value() \|\| !language->region.has_value())
119	0	return return_default_values();
120
121	0	if (auto regional_values = get_regional_values(*language->region); has_value(regional_values))
122	0	return regional_values;
123
124	0	return return_default_values();
125	0	} Unexecuted instantiation: DateTimeFormat.cpp:AK::Vector<Locale::HourCycle, 0ul> Locale::find_regional_values_for_locale<AK::Vector<Locale::HourCycle, 0ul>, AK::Vector<Locale::HourCycle, 0ul> (&)(AK::StringView)>(AK::StringView, AK::Vector<Locale::HourCycle, 0ul> (&)(AK::StringView)) Unexecuted instantiation: DateTimeFormat.cpp:AK::Optional<unsigned char> Locale::find_regional_values_for_locale<AK::Optional<unsigned char>, AK::Optional<unsigned char> (&)(AK::StringView)>(AK::StringView, AK::Optional<unsigned char> (&)(AK::StringView)) Unexecuted instantiation: DateTimeFormat.cpp:AK::Optional<Locale::Weekday> Locale::find_regional_values_for_locale<AK::Optional<Locale::Weekday>, AK::Optional<Locale::Weekday> (&)(AK::StringView)>(AK::StringView, AK::Optional<Locale::Weekday> (&)(AK::StringView))
126
127		// https://unicode.org/reports/tr35/tr35-dates.html#Date_Field_Symbol_Table
128		Vector<HourCycle> get_locale_hour_cycles(StringView locale)
129	0	{
130	0	return find_regional_values_for_locale<Vector<HourCycle>>(locale, get_regional_hour_cycles);
131	0	}
132
133		Optional<HourCycle> get_default_regional_hour_cycle(StringView locale)
134	0	{
135	0	if (auto hour_cycles = get_locale_hour_cycles(locale); !hour_cycles.is_empty())
136	0	return hour_cycles.first();
137	0	return {};
138	0	}
139
140		Optional<MinimumDaysRegion> __attribute__((weak)) minimum_days_region_from_string(StringView) { return {}; }
141		Optional<u8> __attribute__((weak)) get_regional_minimum_days(StringView) { return {}; }
142
143		Optional<u8> get_locale_minimum_days(StringView locale)
144	0	{
145	0	return find_regional_values_for_locale<Optional<u8>>(locale, get_regional_minimum_days);
146	0	}
147
148		Optional<FirstDayRegion> __attribute__((weak)) first_day_region_from_string(StringView) { return {}; }
149		Optional<Weekday> __attribute__((weak)) get_regional_first_day(StringView) { return {}; }
150
151		Optional<Weekday> get_locale_first_day(StringView locale)
152	0	{
153	0	return find_regional_values_for_locale<Optional<Weekday>>(locale, get_regional_first_day);
154	0	}
155
156		Optional<WeekendStartRegion> __attribute__((weak)) weekend_start_region_from_string(StringView) { return {}; }
157		Optional<Weekday> __attribute__((weak)) get_regional_weekend_start(StringView) { return {}; }
158
159		Optional<Weekday> get_locale_weekend_start(StringView locale)
160	0	{
161	0	return find_regional_values_for_locale<Optional<Weekday>>(locale, get_regional_weekend_start);
162	0	}
163
164		Optional<WeekendEndRegion> __attribute__((weak)) weekend_end_region_from_string(StringView) { return {}; }
165		Optional<Weekday> __attribute__((weak)) get_regional_weekend_end(StringView) { return {}; }
166
167		Optional<Weekday> get_locale_weekend_end(StringView locale)
168	0	{
169	0	return find_regional_values_for_locale<Optional<Weekday>>(locale, get_regional_weekend_end);
170	0	}
171
172		String combine_skeletons(StringView first, StringView second)
173	0	{
174		// https://unicode.org/reports/tr35/tr35-dates.html#availableFormats_appendItems
175	0	constexpr auto field_order = Array {
176	0	"G"sv, // Era
177	0	"yYuUr"sv, // Year
178	0	"ML"sv, // Month
179	0	"dDFg"sv, // Day
180	0	"Eec"sv, // Weekday
181	0	"abB"sv, // Period
182	0	"hHKk"sv, // Hour
183	0	"m"sv, // Minute
184	0	"sSA"sv, // Second
185	0	"zZOvVXx"sv, // Zone
186	0	};
187
188	0	StringBuilder builder;
189
190	0	auto append_from_skeleton = [&](auto skeleton, auto ch) {
191	0	auto first_index = skeleton.find(ch);
192	0	if (!first_index.has_value())
193	0	return false;
194
195	0	auto last_index = skeleton.find_last(ch);
196
197	0	builder.append(skeleton.substring_view(first_index, last_index - *first_index + 1));
198	0	return true;
199	0	};
200
201	0	for (auto fields : field_order) {
202	0	for (auto ch : fields) {
203	0	if (append_from_skeleton(first, ch))
204	0	break;
205	0	if (append_from_skeleton(second, ch))
206	0	break;
207	0	}
208	0	}
209
210	0	return MUST(builder.to_string());
211	0	}
212
213		Optional<CalendarFormat> __attribute__((weak)) get_calendar_date_format(StringView, StringView) { return {}; }
214		Optional<CalendarFormat> __attribute__((weak)) get_calendar_time_format(StringView, StringView) { return {}; }
215		Optional<CalendarFormat> __attribute__((weak)) get_calendar_date_time_format(StringView, StringView) { return {}; }
216
217		Optional<CalendarFormat> get_calendar_format(StringView locale, StringView calendar, CalendarFormatType type)
218	0	{
219	0	switch (type) {
220	0	case CalendarFormatType::Date:
221	0	return get_calendar_date_format(locale, calendar);
222	0	case CalendarFormatType::Time:
223	0	return get_calendar_time_format(locale, calendar);
224	0	case CalendarFormatType::DateTime:
225	0	return get_calendar_date_time_format(locale, calendar);
226	0	default:
227	0	VERIFY_NOT_REACHED();
228	0	}
229	0	}
230
231		Vector<CalendarPattern> __attribute__((weak)) get_calendar_available_formats(StringView, StringView) { return {}; }
232		Optional<CalendarRangePattern> __attribute__((weak)) get_calendar_default_range_format(StringView, StringView) { return {}; }
233		Vector<CalendarRangePattern> __attribute__((weak)) get_calendar_range_formats(StringView, StringView, StringView) { return {}; }
234		Vector<CalendarRangePattern> __attribute__((weak)) get_calendar_range12_formats(StringView, StringView, StringView) { return {}; }
235		Optional<StringView> __attribute__((weak)) get_calendar_era_symbol(StringView, StringView, CalendarPatternStyle, Era) { return {}; }
236		Optional<StringView> __attribute__((weak)) get_calendar_month_symbol(StringView, StringView, CalendarPatternStyle, Month) { return {}; }
237		Optional<StringView> __attribute__((weak)) get_calendar_weekday_symbol(StringView, StringView, CalendarPatternStyle, Weekday) { return {}; }
238		Optional<StringView> __attribute__((weak)) get_calendar_day_period_symbol(StringView, StringView, CalendarPatternStyle, DayPeriod) { return {}; }
239		Optional<StringView> __attribute__((weak)) get_calendar_day_period_symbol_for_hour(StringView, StringView, CalendarPatternStyle, u8) { return {}; }
240
241		Optional<StringView> __attribute__((weak)) get_time_zone_name(StringView, StringView, CalendarPatternStyle, TimeZone::InDST) { return {}; }
242		Optional<TimeZoneFormat> __attribute__((weak)) get_time_zone_format(StringView) { return {}; }
243
244		static Optional<String> format_time_zone_offset(StringView locale, CalendarPatternStyle style, i64 offset_seconds)
245	0	{
246	0	auto formats = get_time_zone_format(locale);
247	0	if (!formats.has_value())
248	0	return {};
249
250	0	auto number_system = get_preferred_keyword_value_for_locale(locale, "nu"sv);
251	0	if (!number_system.has_value())
252	0	return {};
253
254	0	if (offset_seconds == 0)
255	0	return MUST(String::from_utf8(formats->gmt_zero_format));
256
257	0	auto sign = offset_seconds > 0 ? formats->symbol_ahead_sign : formats->symbol_behind_sign;
258	0	auto separator = offset_seconds > 0 ? formats->symbol_ahead_separator : formats->symbol_behind_separator;
259	0	offset_seconds = llabs(offset_seconds);
260
261	0	auto offset_hours = offset_seconds / 3'600;
262	0	offset_seconds %= 3'600;
263
264	0	auto offset_minutes = offset_seconds / 60;
265	0	offset_seconds %= 60;
266
267	0	StringBuilder builder;
268	0	builder.append(sign);
269
270	0	switch (style) {
271		// The long format always uses 2-digit hours field and minutes field, with optional 2-digit seconds field.
272	0	case CalendarPatternStyle::LongOffset:
273	0	builder.appendff("{:02}{}{:02}", offset_hours, separator, offset_minutes);
274	0	if (offset_seconds > 0)
275	0	builder.appendff("{}{:02}", separator, offset_seconds);
276	0	break;
277
278		// The short format is intended for the shortest representation and uses hour fields without leading zero, with optional 2-digit minutes and seconds fields.
279	0	case CalendarPatternStyle::ShortOffset:
280	0	builder.appendff("{}", offset_hours);
281	0	if (offset_minutes > 0) {
282	0	builder.appendff("{}{:02}", separator, offset_minutes);
283	0	if (offset_seconds > 0)
284	0	builder.appendff("{}{:02}", separator, offset_seconds);
285	0	}
286	0	break;
287
288	0	default:
289	0	VERIFY_NOT_REACHED();
290	0	}
291
292		// The digits used for hours, minutes and seconds fields in this format are the locale's default decimal digits.
293	0	auto result = replace_digits_for_number_system(*number_system, builder.string_view());
294	0	return MUST(MUST(String::from_utf8(formats->gmt_format)).replace("{0}"sv, result, ReplaceMode::FirstOnly));
295	0	}
296
297		// https://unicode.org/reports/tr35/tr35-dates.html#Time_Zone_Format_Terminology
298		String format_time_zone(StringView locale, StringView time_zone, CalendarPatternStyle style, AK::UnixDateTime time)
299	0	{
300	0	auto offset = TimeZone::get_time_zone_offset(time_zone, time);
301	0	if (!offset.has_value())
302	0	return MUST(String::from_utf8(time_zone));
303
304	0	switch (style) {
305	0	case CalendarPatternStyle::Short:
306	0	case CalendarPatternStyle::Long:
307	0	case CalendarPatternStyle::ShortGeneric:
308	0	case CalendarPatternStyle::LongGeneric:
309	0	if (auto name = get_time_zone_name(locale, time_zone, style, offset->in_dst); name.has_value())
310	0	return MUST(String::from_utf8(*name));
311	0	break;
312
313	0	case CalendarPatternStyle::ShortOffset:
314	0	case CalendarPatternStyle::LongOffset:
315	0	if (auto formatted_offset = format_time_zone_offset(locale, style, offset->seconds); formatted_offset.has_value())
316	0	return formatted_offset.release_value();
317	0	return MUST(String::from_utf8(time_zone));
318
319	0	default:
320	0	VERIFY_NOT_REACHED();
321	0	}
322
323		// If more styles are added, consult the following table to ensure always falling back to GMT offset is still correct:
324		// https://unicode.org/reports/tr35/tr35-dates.html#dfst-zone
325	0	switch (style) {
326	0	case CalendarPatternStyle::Short:
327	0	case CalendarPatternStyle::ShortGeneric:
328	0	return format_time_zone(locale, time_zone, CalendarPatternStyle::ShortOffset, time);
329
330	0	case CalendarPatternStyle::Long:
331	0	case CalendarPatternStyle::LongGeneric:
332	0	return format_time_zone(locale, time_zone, CalendarPatternStyle::LongOffset, time);
333
334	0	default:
335	0	VERIFY_NOT_REACHED();
336	0	}
337	0	}
338
339		}