Source/JavaScriptCore/runtime/IntlObjectInlines.h - external/github.com/WebKit/webkit - Git at Google

 /*
  * Copyright (C) 2016 Yusuke Suzuki <yusuke.suzuki@sslab.ics.keio.ac.jp>
  * Copyright (C) 2016 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  * THE POSSIBILITY OF SUCH DAMAGE.
  */

 #pragma once

 #include "BuiltinNames.h"
 #include "IntlObject.h"
 #include "JSBoundFunction.h"
 #include "JSObject.h"
 #include "ObjectConstructor.h"
 #include <unicode/ucol.h>

 namespace JSC {

 template<typename StringType>
 static constexpr uint32_t computeTwoCharacters16Code(const StringType& string)
 {
     return static_cast<uint16_t>(string.characterAt(0)) | (static_cast<uint32_t>(static_cast<uint16_t>(string.characterAt(1))) << 16);
 }

 template<typename Predicate> String bestAvailableLocale(const String& locale, Predicate predicate)
 {
     // BestAvailableLocale (availableLocales, locale)
     // https://tc39.github.io/ecma402/#sec-bestavailablelocale

     String candidate = locale;
     while (!candidate.isEmpty()) {
         if (predicate(candidate))
             return candidate;

         size_t pos = candidate.reverseFind('-');
         if (pos == notFound)
             return String();

         if (pos >= 2 && candidate[pos - 2] == '-')
             pos -= 2;

         candidate = candidate.left(pos);
     }

     return String();
 }

 template<typename Constructor, typename Factory>
 JSValue constructIntlInstanceWithWorkaroundForLegacyIntlConstructor(JSGlobalObject* globalObject, JSValue thisValue, Constructor* callee, Factory factory)
 {
     // FIXME: Workaround to provide compatibility with ECMA-402 1.0 call/apply patterns.
     // https://bugs.webkit.org/show_bug.cgi?id=153679
     VM& vm = globalObject->vm();
     auto scope = DECLARE_THROW_SCOPE(vm);

     auto* instance = factory(vm);
     RETURN_IF_EXCEPTION(scope, JSValue());

     if (thisValue.isObject()) {
         JSObject* thisObject = asObject(thisValue);
         ASSERT(!callee->template inherits<JSBoundFunction>());
         JSValue prototype = callee->getDirect(vm, vm.propertyNames->prototype); // Passed constructors always have `prototype` which cannot be deleted.
         ASSERT(prototype);
         bool hasInstance = JSObject::defaultHasInstance(globalObject, thisObject, prototype);
         RETURN_IF_EXCEPTION(scope, JSValue());
         if (hasInstance) {
             PropertyDescriptor descriptor(instance, PropertyAttribute::ReadOnly | PropertyAttribute::DontEnum | PropertyAttribute::DontDelete);
             scope.release();
             thisObject->methodTable()->defineOwnProperty(thisObject, globalObject, vm.propertyNames->builtinNames().intlLegacyConstructedSymbol(), descriptor, true);
             return thisObject;
         }
     }
     return instance;
 }

 template<typename InstanceType>
 InstanceType* unwrapForLegacyIntlConstructor(JSGlobalObject* globalObject, JSValue thisValue, JSObject* constructor)
 {
     VM& vm = globalObject->vm();
     auto scope = DECLARE_THROW_SCOPE(vm);

     JSObject* thisObject = jsDynamicCast<JSObject*>(thisValue);
     if (UNLIKELY(!thisObject))
         return nullptr;

     auto* instance = jsDynamicCast<InstanceType*>(thisObject);
     if (LIKELY(instance))
         return instance;

     ASSERT(!constructor->template inherits<JSBoundFunction>());
     JSValue prototype = constructor->getDirect(vm, vm.propertyNames->prototype); // Passed constructors always have `prototype` which cannot be deleted.
     ASSERT(prototype);
     bool hasInstance = JSObject::defaultHasInstance(globalObject, thisObject, prototype);
     RETURN_IF_EXCEPTION(scope, nullptr);
     if (!hasInstance)
         return nullptr;

     JSValue value = thisObject->get(globalObject, vm.propertyNames->builtinNames().intlLegacyConstructedSymbol());
     RETURN_IF_EXCEPTION(scope, nullptr);
     return jsDynamicCast<InstanceType*>(value);
 }

 template<typename ResultType>
 ResultType intlOption(JSGlobalObject* globalObject, JSObject* options, PropertyName property, std::initializer_list<std::pair<ASCIILiteral, ResultType>> values, ASCIILiteral notFoundMessage, ResultType fallback)
 {
     // GetOption (options, property, type="string", values, fallback)
     // https://tc39.github.io/ecma402/#sec-getoption

     ASSERT(values.size() > 0);

     VM& vm = globalObject->vm();
     auto scope = DECLARE_THROW_SCOPE(vm);

     if (!options)
         return fallback;

     JSValue value = options->get(globalObject, property);
     RETURN_IF_EXCEPTION(scope, { });

     if (!value.isUndefined()) {
         String stringValue = value.toWTFString(globalObject);
         RETURN_IF_EXCEPTION(scope, { });

         for (const auto& entry : values) {
             if (entry.first == stringValue)
                 return entry.second;
         }
         throwException(globalObject, scope, createRangeError(globalObject, notFoundMessage));
         return { };
     }

     return fallback;
 }

 template<typename ResultType>
 ResultType intlStringOrBooleanOption(JSGlobalObject* globalObject, JSObject* options, PropertyName property, ResultType trueValue, ResultType falsyValue, std::initializer_list<std::pair<ASCIILiteral, ResultType>> values, ASCIILiteral notFoundMessage, ResultType fallback)
 {
     // https://tc39.es/proposal-intl-numberformat-v3/out/negotiation/diff.html#sec-getstringorbooleanoption

     ASSERT(values.size() > 0);

     VM& vm = globalObject->vm();
     auto scope = DECLARE_THROW_SCOPE(vm);

     if (!options)
         return fallback;

     JSValue value = options->get(globalObject, property);
     RETURN_IF_EXCEPTION(scope, { });

     if (value.isUndefined())
         return fallback;

     if (value.isBoolean() && value.asBoolean())
         return trueValue;

     bool valueBoolean = value.toBoolean(globalObject);
     RETURN_IF_EXCEPTION(scope, { });

     if (!valueBoolean)
         return falsyValue;

     String stringValue = value.toWTFString(globalObject);
     RETURN_IF_EXCEPTION(scope, { });

     // FIXME: We need to know whether this fallback is actually correct.
     // https://github.com/tc39/proposal-intl-numberformat-v3/issues/111
     if (stringValue == "true"_s || stringValue == "false"_s)
         return fallback;

     for (const auto& entry : values) {
         if (entry.first == stringValue)
             return entry.second;
     }

     throwRangeError(globalObject, scope, notFoundMessage);
     return { };
 }

 ALWAYS_INLINE bool canUseASCIIUCADUCETComparison(UChar character)
 {
     return isASCII(character) && ducetLevel1Weights[character];
 }

 ALWAYS_INLINE bool canUseASCIIUCADUCETComparison(LChar character)
 {
     return ducetLevel1Weights[character];
 }

 ALWAYS_INLINE bool followedByNonLatinCharacter(const UChar* characters, unsigned length, unsigned index)
 {
     unsigned nextIndex = index + 1;
     if (length > nextIndex)
         return !isLatin1(characters[nextIndex]);
     return false;
 }

 ALWAYS_INLINE bool followedByNonLatinCharacter(const LChar*, unsigned, unsigned)
 {
     return false;
 }

 template<typename CharacterType1, typename CharacterType2>
 UCollationResult compareASCIIWithUCADUCETLevel3(const CharacterType1* characters1, const CharacterType2* characters2, unsigned length)
 {
     for (unsigned position = 0; position < length; ++position) {
         auto lhs = characters1[position];
         auto rhs = characters2[position];
         uint8_t leftWeight = ducetLevel3Weights[lhs];
         uint8_t rightWeight = ducetLevel3Weights[rhs];
         if (leftWeight == rightWeight)
             continue;
         return leftWeight > rightWeight ? UCOL_GREATER : UCOL_LESS;
     }
     return UCOL_EQUAL;
 }

 template<typename CharacterType1, typename CharacterType2>
 inline std::optional<UCollationResult> compareASCIIWithUCADUCET(const CharacterType1* characters1, unsigned length1, const CharacterType2* characters2, unsigned length2)
 {
     if (length1 == length2) {
         if (equal(characters1, characters2, length1))
             return UCOL_EQUAL;
     }

     unsigned commonLength = std::min(length1, length2);
     for (unsigned position = 0; position < commonLength; ++position) {
         auto lhs = characters1[position];
         auto rhs = characters2[position];

         if (!canUseASCIIUCADUCETComparison(lhs) || !canUseASCIIUCADUCETComparison(rhs))
             return std::nullopt;

         uint8_t leftWeight = ducetLevel1Weights[lhs];
         uint8_t rightWeight = ducetLevel1Weights[rhs];
         if (leftWeight == rightWeight)
             continue;

         // If the following character is a non-latin, then it is possible that current and next characters can be combined into different character.
         if (followedByNonLatinCharacter(characters1, length1, position) || followedByNonLatinCharacter(characters2, length2, position))
             return std::nullopt;

         return leftWeight > rightWeight ? UCOL_GREATER : UCOL_LESS;
     }

     if (length1 == length2)
         return compareASCIIWithUCADUCETLevel3(characters1, characters2, length1);

     // If the next character is valid, then we do not need to look into the rest of characters.
     if (length1 > length2) {
         auto lhs = characters1[length2];
         if (!canUseASCIIUCADUCETComparison(lhs))
             return std::nullopt;
         return UCOL_GREATER;
     }

     auto rhs = characters2[length1];
     if (!canUseASCIIUCADUCETComparison(rhs))
         return std::nullopt;
     return UCOL_LESS;
 }

 // https://tc39.es/ecma402/#sec-getoptionsobject
 inline JSObject* intlGetOptionsObject(JSGlobalObject* globalObject, JSValue options)
 {
     VM& vm = globalObject->vm();
     auto scope = DECLARE_THROW_SCOPE(vm);
     if (options.isUndefined())
         return nullptr;
     if (LIKELY(options.isObject()))
         return asObject(options);
     throwTypeError(globalObject, scope, "options argument is not an object or undefined"_s);
     return nullptr;
 }

 // https://tc39.es/ecma402/#sec-coerceoptionstoobject
 inline JSObject* intlCoerceOptionsToObject(JSGlobalObject* globalObject, JSValue optionsValue)
 {
     VM& vm = globalObject->vm();
     auto scope = DECLARE_THROW_SCOPE(vm);
     if (optionsValue.isUndefined())
         return nullptr;
     JSObject* options = optionsValue.toObject(globalObject);
     RETURN_IF_EXCEPTION(scope, nullptr);
     return options;
 }

 template<typename Container>
 JSArray* createArrayFromStringVector(JSGlobalObject* globalObject, const Container& elements)
 {
     VM& vm = globalObject->vm();
     auto scope = DECLARE_THROW_SCOPE(vm);

     JSArray* result = JSArray::tryCreate(vm, globalObject->arrayStructureForIndexingTypeDuringAllocation(ArrayWithContiguous), elements.size());
     if (!result) {
         throwOutOfMemoryError(globalObject, scope);
         return nullptr;
     }
     for (unsigned index = 0; index < elements.size(); ++index) {
         result->putDirectIndex(globalObject, index, jsString(vm, elements[index]));
         RETURN_IF_EXCEPTION(scope, { });
     }
     return result;
 }

 template<typename Container>
 JSArray* createArrayFromIntVector(JSGlobalObject* globalObject, const Container& elements)
 {
     VM& vm = globalObject->vm();
     auto scope = DECLARE_THROW_SCOPE(vm);

     JSArray* result = JSArray::tryCreate(vm, globalObject->arrayStructureForIndexingTypeDuringAllocation(ArrayWithContiguous), elements.size());
     if (!result) {
         throwOutOfMemoryError(globalObject, scope);
         return nullptr;
     }
     for (unsigned index = 0; index < elements.size(); ++index) {
         result->putDirectIndex(globalObject, index, jsNumber(elements[index]));
         RETURN_IF_EXCEPTION(scope, { });
     }
     return result;
 }

 class ListFormatInput {
     WTF_MAKE_NONCOPYABLE(ListFormatInput);
 public:
     ListFormatInput(Vector<String, 4>&& strings)
         : m_strings(WTFMove(strings))
     {
         m_stringPointers.reserveInitialCapacity(m_strings.size());
         m_stringLengths.reserveInitialCapacity(m_strings.size());
         for (auto& string : m_strings) {
             string.convertTo16Bit();
             m_stringPointers.append(string.characters16());
             m_stringLengths.append(string.length());
         }
     }

     int32_t size() const { return m_stringPointers.size(); }
     const UChar* const* stringPointers() const { return m_stringPointers.data(); }
     const int32_t* stringLengths() const { return m_stringLengths.data(); }

 private:
     Vector<String, 4> m_strings;
     Vector<const UChar*, 4> m_stringPointers;
     Vector<int32_t, 4> m_stringLengths;
 };

 } // namespace JSC
	/*
	* Copyright (C) 2016 Yusuke Suzuki <yusuke.suzuki@sslab.ics.keio.ac.jp>
	* Copyright (C) 2016 Apple Inc. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	*
	* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
	* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
	* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
	* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
	* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
	* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
	* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
	* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
	* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
	* THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#pragma once

	#include "BuiltinNames.h"
	#include "IntlObject.h"
	#include "JSBoundFunction.h"
	#include "JSObject.h"
	#include "ObjectConstructor.h"
	#include <unicode/ucol.h>

	namespace JSC {

	template<typename StringType>
	static constexpr uint32_t computeTwoCharacters16Code(const StringType& string)
	{
	return static_cast<uint16_t>(string.characterAt(0)) \| (static_cast<uint32_t>(static_cast<uint16_t>(string.characterAt(1))) << 16);
	}

	template<typename Predicate> String bestAvailableLocale(const String& locale, Predicate predicate)
	{
	// BestAvailableLocale (availableLocales, locale)
	// https://tc39.github.io/ecma402/#sec-bestavailablelocale

	String candidate = locale;
	while (!candidate.isEmpty()) {
	if (predicate(candidate))
	return candidate;

	size_t pos = candidate.reverseFind('-');
	if (pos == notFound)
	return String();

	if (pos >= 2 && candidate[pos - 2] == '-')
	pos -= 2;

	candidate = candidate.left(pos);
	}

	return String();
	}

	template<typename Constructor, typename Factory>
	JSValue constructIntlInstanceWithWorkaroundForLegacyIntlConstructor(JSGlobalObject* globalObject, JSValue thisValue, Constructor* callee, Factory factory)
	{
	// FIXME: Workaround to provide compatibility with ECMA-402 1.0 call/apply patterns.
	// https://bugs.webkit.org/show_bug.cgi?id=153679
	VM& vm = globalObject->vm();
	auto scope = DECLARE_THROW_SCOPE(vm);

	auto* instance = factory(vm);
	RETURN_IF_EXCEPTION(scope, JSValue());

	if (thisValue.isObject()) {
	JSObject* thisObject = asObject(thisValue);
	ASSERT(!callee->template inherits<JSBoundFunction>());
	JSValue prototype = callee->getDirect(vm, vm.propertyNames->prototype); // Passed constructors always have `prototype` which cannot be deleted.
	ASSERT(prototype);
	bool hasInstance = JSObject::defaultHasInstance(globalObject, thisObject, prototype);
	RETURN_IF_EXCEPTION(scope, JSValue());
	if (hasInstance) {
	PropertyDescriptor descriptor(instance, PropertyAttribute::ReadOnly \| PropertyAttribute::DontEnum \| PropertyAttribute::DontDelete);
	scope.release();
	thisObject->methodTable()->defineOwnProperty(thisObject, globalObject, vm.propertyNames->builtinNames().intlLegacyConstructedSymbol(), descriptor, true);
	return thisObject;
	}
	}
	return instance;
	}

	template<typename InstanceType>
	InstanceType* unwrapForLegacyIntlConstructor(JSGlobalObject* globalObject, JSValue thisValue, JSObject* constructor)
	{
	VM& vm = globalObject->vm();
	auto scope = DECLARE_THROW_SCOPE(vm);

	JSObject* thisObject = jsDynamicCast<JSObject*>(thisValue);
	if (UNLIKELY(!thisObject))
	return nullptr;

	auto* instance = jsDynamicCast<InstanceType*>(thisObject);
	if (LIKELY(instance))
	return instance;

	ASSERT(!constructor->template inherits<JSBoundFunction>());
	JSValue prototype = constructor->getDirect(vm, vm.propertyNames->prototype); // Passed constructors always have `prototype` which cannot be deleted.
	ASSERT(prototype);
	bool hasInstance = JSObject::defaultHasInstance(globalObject, thisObject, prototype);
	RETURN_IF_EXCEPTION(scope, nullptr);
	if (!hasInstance)
	return nullptr;

	JSValue value = thisObject->get(globalObject, vm.propertyNames->builtinNames().intlLegacyConstructedSymbol());
	RETURN_IF_EXCEPTION(scope, nullptr);
	return jsDynamicCast<InstanceType*>(value);
	}

	template<typename ResultType>
	ResultType intlOption(JSGlobalObject* globalObject, JSObject* options, PropertyName property, std::initializer_list<std::pair<ASCIILiteral, ResultType>> values, ASCIILiteral notFoundMessage, ResultType fallback)
	{
	// GetOption (options, property, type="string", values, fallback)
	// https://tc39.github.io/ecma402/#sec-getoption

	ASSERT(values.size() > 0);

	VM& vm = globalObject->vm();
	auto scope = DECLARE_THROW_SCOPE(vm);

	if (!options)
	return fallback;

	JSValue value = options->get(globalObject, property);
	RETURN_IF_EXCEPTION(scope, { });

	if (!value.isUndefined()) {
	String stringValue = value.toWTFString(globalObject);
	RETURN_IF_EXCEPTION(scope, { });

	for (const auto& entry : values) {
	if (entry.first == stringValue)
	return entry.second;
	}
	throwException(globalObject, scope, createRangeError(globalObject, notFoundMessage));
	return { };
	}

	return fallback;
	}

	template<typename ResultType>
	ResultType intlStringOrBooleanOption(JSGlobalObject* globalObject, JSObject* options, PropertyName property, ResultType trueValue, ResultType falsyValue, std::initializer_list<std::pair<ASCIILiteral, ResultType>> values, ASCIILiteral notFoundMessage, ResultType fallback)
	{
	// https://tc39.es/proposal-intl-numberformat-v3/out/negotiation/diff.html#sec-getstringorbooleanoption

	ASSERT(values.size() > 0);

	VM& vm = globalObject->vm();
	auto scope = DECLARE_THROW_SCOPE(vm);

	if (!options)
	return fallback;

	JSValue value = options->get(globalObject, property);
	RETURN_IF_EXCEPTION(scope, { });

	if (value.isUndefined())
	return fallback;

	if (value.isBoolean() && value.asBoolean())
	return trueValue;

	bool valueBoolean = value.toBoolean(globalObject);
	RETURN_IF_EXCEPTION(scope, { });

	if (!valueBoolean)
	return falsyValue;

	String stringValue = value.toWTFString(globalObject);
	RETURN_IF_EXCEPTION(scope, { });

	// FIXME: We need to know whether this fallback is actually correct.
	// https://github.com/tc39/proposal-intl-numberformat-v3/issues/111
	if (stringValue == "true"_s \|\| stringValue == "false"_s)
	return fallback;

	for (const auto& entry : values) {
	if (entry.first == stringValue)
	return entry.second;
	}

	throwRangeError(globalObject, scope, notFoundMessage);
	return { };
	}

	ALWAYS_INLINE bool canUseASCIIUCADUCETComparison(UChar character)
	{
	return isASCII(character) && ducetLevel1Weights[character];
	}

	ALWAYS_INLINE bool canUseASCIIUCADUCETComparison(LChar character)
	{
	return ducetLevel1Weights[character];
	}

	ALWAYS_INLINE bool followedByNonLatinCharacter(const UChar* characters, unsigned length, unsigned index)
	{
	unsigned nextIndex = index + 1;
	if (length > nextIndex)
	return !isLatin1(characters[nextIndex]);
	return false;
	}

	ALWAYS_INLINE bool followedByNonLatinCharacter(const LChar*, unsigned, unsigned)
	{
	return false;
	}

	template<typename CharacterType1, typename CharacterType2>
	UCollationResult compareASCIIWithUCADUCETLevel3(const CharacterType1* characters1, const CharacterType2* characters2, unsigned length)
	{
	for (unsigned position = 0; position < length; ++position) {
	auto lhs = characters1[position];
	auto rhs = characters2[position];
	uint8_t leftWeight = ducetLevel3Weights[lhs];
	uint8_t rightWeight = ducetLevel3Weights[rhs];
	if (leftWeight == rightWeight)
	continue;
	return leftWeight > rightWeight ? UCOL_GREATER : UCOL_LESS;
	}
	return UCOL_EQUAL;
	}

	template<typename CharacterType1, typename CharacterType2>
	inline std::optional<UCollationResult> compareASCIIWithUCADUCET(const CharacterType1* characters1, unsigned length1, const CharacterType2* characters2, unsigned length2)
	{
	if (length1 == length2) {
	if (equal(characters1, characters2, length1))
	return UCOL_EQUAL;
	}

	unsigned commonLength = std::min(length1, length2);
	for (unsigned position = 0; position < commonLength; ++position) {
	auto lhs = characters1[position];
	auto rhs = characters2[position];

	if (!canUseASCIIUCADUCETComparison(lhs) \|\| !canUseASCIIUCADUCETComparison(rhs))
	return std::nullopt;

	uint8_t leftWeight = ducetLevel1Weights[lhs];
	uint8_t rightWeight = ducetLevel1Weights[rhs];
	if (leftWeight == rightWeight)
	continue;

	// If the following character is a non-latin, then it is possible that current and next characters can be combined into different character.
	if (followedByNonLatinCharacter(characters1, length1, position) \|\| followedByNonLatinCharacter(characters2, length2, position))
	return std::nullopt;

	return leftWeight > rightWeight ? UCOL_GREATER : UCOL_LESS;
	}

	if (length1 == length2)
	return compareASCIIWithUCADUCETLevel3(characters1, characters2, length1);

	// If the next character is valid, then we do not need to look into the rest of characters.
	if (length1 > length2) {
	auto lhs = characters1[length2];
	if (!canUseASCIIUCADUCETComparison(lhs))
	return std::nullopt;
	return UCOL_GREATER;
	}

	auto rhs = characters2[length1];
	if (!canUseASCIIUCADUCETComparison(rhs))
	return std::nullopt;
	return UCOL_LESS;
	}

	// https://tc39.es/ecma402/#sec-getoptionsobject
	inline JSObject* intlGetOptionsObject(JSGlobalObject* globalObject, JSValue options)
	{
	VM& vm = globalObject->vm();
	auto scope = DECLARE_THROW_SCOPE(vm);
	if (options.isUndefined())
	return nullptr;
	if (LIKELY(options.isObject()))
	return asObject(options);
	throwTypeError(globalObject, scope, "options argument is not an object or undefined"_s);
	return nullptr;
	}

	// https://tc39.es/ecma402/#sec-coerceoptionstoobject
	inline JSObject* intlCoerceOptionsToObject(JSGlobalObject* globalObject, JSValue optionsValue)
	{
	VM& vm = globalObject->vm();
	auto scope = DECLARE_THROW_SCOPE(vm);
	if (optionsValue.isUndefined())
	return nullptr;
	JSObject* options = optionsValue.toObject(globalObject);
	RETURN_IF_EXCEPTION(scope, nullptr);
	return options;
	}

	template<typename Container>
	JSArray* createArrayFromStringVector(JSGlobalObject* globalObject, const Container& elements)
	{
	VM& vm = globalObject->vm();
	auto scope = DECLARE_THROW_SCOPE(vm);

	JSArray* result = JSArray::tryCreate(vm, globalObject->arrayStructureForIndexingTypeDuringAllocation(ArrayWithContiguous), elements.size());
	if (!result) {
	throwOutOfMemoryError(globalObject, scope);
	return nullptr;
	}
	for (unsigned index = 0; index < elements.size(); ++index) {
	result->putDirectIndex(globalObject, index, jsString(vm, elements[index]));
	RETURN_IF_EXCEPTION(scope, { });
	}
	return result;
	}

	template<typename Container>
	JSArray* createArrayFromIntVector(JSGlobalObject* globalObject, const Container& elements)
	{
	VM& vm = globalObject->vm();
	auto scope = DECLARE_THROW_SCOPE(vm);

	JSArray* result = JSArray::tryCreate(vm, globalObject->arrayStructureForIndexingTypeDuringAllocation(ArrayWithContiguous), elements.size());
	if (!result) {
	throwOutOfMemoryError(globalObject, scope);
	return nullptr;
	}
	for (unsigned index = 0; index < elements.size(); ++index) {
	result->putDirectIndex(globalObject, index, jsNumber(elements[index]));
	RETURN_IF_EXCEPTION(scope, { });
	}
	return result;
	}

	class ListFormatInput {
	WTF_MAKE_NONCOPYABLE(ListFormatInput);
	public:
	ListFormatInput(Vector<String, 4>&& strings)
	: m_strings(WTFMove(strings))
	{
	m_stringPointers.reserveInitialCapacity(m_strings.size());
	m_stringLengths.reserveInitialCapacity(m_strings.size());
	for (auto& string : m_strings) {
	string.convertTo16Bit();
	m_stringPointers.append(string.characters16());
	m_stringLengths.append(string.length());
	}
	}

	int32_t size() const { return m_stringPointers.size(); }
	const UChar* const* stringPointers() const { return m_stringPointers.data(); }
	const int32_t* stringLengths() const { return m_stringLengths.data(); }

	private:
	Vector<String, 4> m_strings;
	Vector<const UChar*, 4> m_stringPointers;
	Vector<int32_t, 4> m_stringLengths;
	};

	} // namespace JSC