third_party/WebKit/Source/wtf/text/AtomicString.cpp - chromium/src.git - Git at Google

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Patrick Gansterer <[email protected]>
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  *
  */

 #include "wtf/text/AtomicString.h"

 #include "wtf/HashSet.h"
 #include "wtf/WTFThreadData.h"
 #include "wtf/dtoa.h"
 #include "wtf/text/IntegerToStringConversion.h"
 #include "wtf/text/StringHash.h"
 #include "wtf/text/UTF8.h"

 namespace WTF {

 using namespace Unicode;

 static_assert(sizeof(AtomicString) == sizeof(String), "AtomicString and String must be same size");

 class AtomicStringTable {
     USING_FAST_MALLOC(AtomicStringTable);
     WTF_MAKE_NONCOPYABLE(AtomicStringTable);
 public:
     static AtomicStringTable* create(WTFThreadData& data)
     {
         data.m_atomicStringTable = new AtomicStringTable;
         data.m_atomicStringTableDestructor = AtomicStringTable::destroy;
         data.m_atomicStringTable->addStaticStrings();
         return data.m_atomicStringTable;
     }

     StringImpl* addStringImpl(StringImpl* string)
     {
         if (!string->length())
             return StringImpl::empty();

         StringImpl* result = *m_table.add(string).storedValue;

         if (!result->isAtomic())
             result->setIsAtomic(true);

         ASSERT(!string->isStatic() || result->isStatic());
         return result;
     }

     HashSet<StringImpl*>& table()
     {
         return m_table;
     }

 private:
     AtomicStringTable() { }

     void addStaticStrings()
     {
         const StaticStringsTable& staticStrings = StringImpl::allStaticStrings();

         StaticStringsTable::const_iterator it = staticStrings.begin();
         for (; it != staticStrings.end(); ++it) {
             addStringImpl(it->value);
         }
     }

     static void destroy(AtomicStringTable* table)
     {
         HashSet<StringImpl*>::iterator end = table->m_table.end();
         for (HashSet<StringImpl*>::iterator iter = table->m_table.begin(); iter != end; ++iter) {
             StringImpl* string = *iter;
             if (!string->isStatic()) {
                 ASSERT(string->isAtomic());
                 string->setIsAtomic(false);
             }
         }
         delete table;
     }

     HashSet<StringImpl*> m_table;
 };

 static inline AtomicStringTable& atomicStringTable()
 {
     // Once possible we should make this non-lazy (constructed in WTFThreadData's constructor).
     WTFThreadData& data = wtfThreadData();
     AtomicStringTable* table = data.atomicStringTable();
     if (UNLIKELY(!table))
         table = AtomicStringTable::create(data);
     return *table;
 }

 static inline HashSet<StringImpl*>& atomicStrings()
 {
     return atomicStringTable().table();
 }

 void AtomicString::reserveTableCapacity(size_t size)
 {
     atomicStringTable().table().reserveCapacityForSize(size);
 }

 template<typename T, typename HashTranslator>
 static inline PassRefPtr<StringImpl> addToStringTable(const T& value)
 {
     HashSet<StringImpl*>::AddResult addResult = atomicStrings().addWithTranslator<HashTranslator>(value);

     // If the string is newly-translated, then we need to adopt it.
     // The boolean in the pair tells us if that is so.
     return addResult.isNewEntry ? adoptRef(*addResult.storedValue) : *addResult.storedValue;
 }

 PassRefPtr<StringImpl> AtomicString::add(const LChar* c)
 {
     if (!c)
         return nullptr;
     if (!*c)
         return StringImpl::empty();

     return add(c, strlen(reinterpret_cast<const char*>(c)));
 }

 template<typename CharacterType>
 struct HashTranslatorCharBuffer {
     const CharacterType* s;
     unsigned length;
 };

 typedef HashTranslatorCharBuffer<UChar> UCharBuffer;
 struct UCharBufferTranslator {
     static unsigned hash(const UCharBuffer& buf)
     {
         return StringHasher::computeHashAndMaskTop8Bits(buf.s, buf.length);
     }

     static bool equal(StringImpl* const& str, const UCharBuffer& buf)
     {
         return WTF::equal(str, buf.s, buf.length);
     }

     static void translate(StringImpl*& location, const UCharBuffer& buf, unsigned hash)
     {
         location = StringImpl::create8BitIfPossible(buf.s, buf.length).leakRef();
         location->setHash(hash);
         location->setIsAtomic(true);
     }
 };

 template<typename CharacterType>
 struct HashAndCharacters {
     unsigned hash;
     const CharacterType* characters;
     unsigned length;
 };

 template<typename CharacterType>
 struct HashAndCharactersTranslator {
     static unsigned hash(const HashAndCharacters<CharacterType>& buffer)
     {
         ASSERT(buffer.hash == StringHasher::computeHashAndMaskTop8Bits(buffer.characters, buffer.length));
         return buffer.hash;
     }

     static bool equal(StringImpl* const& string, const HashAndCharacters<CharacterType>& buffer)
     {
         return WTF::equal(string, buffer.characters, buffer.length);
     }

     static void translate(StringImpl*& location, const HashAndCharacters<CharacterType>& buffer, unsigned hash)
     {
         location = StringImpl::create(buffer.characters, buffer.length).leakRef();
         location->setHash(hash);
         location->setIsAtomic(true);
     }
 };

 struct HashAndUTF8Characters {
     unsigned hash;
     const char* characters;
     unsigned length;
     unsigned utf16Length;
 };

 struct HashAndUTF8CharactersTranslator {
     static unsigned hash(const HashAndUTF8Characters& buffer)
     {
         return buffer.hash;
     }

     static bool equal(StringImpl* const& string, const HashAndUTF8Characters& buffer)
     {
         if (buffer.utf16Length != string->length())
             return false;

         // If buffer contains only ASCII characters UTF-8 and UTF16 length are the same.
         if (buffer.utf16Length != buffer.length) {
             if (string->is8Bit()) {
                 const LChar* characters8 = string->characters8();
                 return equalLatin1WithUTF8(characters8, characters8 + string->length(), buffer.characters, buffer.characters + buffer.length);
             }
             const UChar* characters16 = string->characters16();
             return equalUTF16WithUTF8(characters16, characters16 + string->length(), buffer.characters, buffer.characters + buffer.length);
         }

         if (string->is8Bit()) {
             const LChar* stringCharacters = string->characters8();

             for (unsigned i = 0; i < buffer.length; ++i) {
                 ASSERT(isASCII(buffer.characters[i]));
                 if (stringCharacters[i] != buffer.characters[i])
                     return false;
             }

             return true;
         }

         const UChar* stringCharacters = string->characters16();

         for (unsigned i = 0; i < buffer.length; ++i) {
             ASSERT(isASCII(buffer.characters[i]));
             if (stringCharacters[i] != buffer.characters[i])
                 return false;
         }

         return true;
     }

     static void translate(StringImpl*& location, const HashAndUTF8Characters& buffer, unsigned hash)
     {
         UChar* target;
         RefPtr<StringImpl> newString = StringImpl::createUninitialized(buffer.utf16Length, target);

         bool isAllASCII;
         const char* source = buffer.characters;
         if (convertUTF8ToUTF16(&source, source + buffer.length, &target, target + buffer.utf16Length, &isAllASCII) != conversionOK)
             ASSERT_NOT_REACHED();

         if (isAllASCII)
             newString = StringImpl::create(buffer.characters, buffer.length);

         location = newString.release().leakRef();
         location->setHash(hash);
         location->setIsAtomic(true);
     }
 };

 PassRefPtr<StringImpl> AtomicString::add(const UChar* s, unsigned length)
 {
     if (!s)
         return nullptr;

     if (!length)
         return StringImpl::empty();

     UCharBuffer buffer = { s, length };
     return addToStringTable<UCharBuffer, UCharBufferTranslator>(buffer);
 }

 PassRefPtr<StringImpl> AtomicString::add(const UChar* s, unsigned length, unsigned existingHash)
 {
     ASSERT(s);
     ASSERT(existingHash);

     if (!length)
         return StringImpl::empty();

     HashAndCharacters<UChar> buffer = { existingHash, s, length };
     return addToStringTable<HashAndCharacters<UChar>, HashAndCharactersTranslator<UChar>>(buffer);
 }

 PassRefPtr<StringImpl> AtomicString::add(const UChar* s)
 {
     if (!s)
         return nullptr;

     unsigned length = 0;
     while (s[length] != UChar(0))
         ++length;

     if (!length)
         return StringImpl::empty();

     UCharBuffer buffer = { s, length };
     return addToStringTable<UCharBuffer, UCharBufferTranslator>(buffer);
 }

 struct SubstringLocation {
     StringImpl* baseString;
     unsigned start;
     unsigned length;
 };

 struct SubstringTranslator {
     static unsigned hash(const SubstringLocation& buffer)
     {
         if (buffer.baseString->is8Bit())
             return StringHasher::computeHashAndMaskTop8Bits(buffer.baseString->characters8() + buffer.start, buffer.length);
         return StringHasher::computeHashAndMaskTop8Bits(buffer.baseString->characters16() + buffer.start, buffer.length);
     }

     static bool equal(StringImpl* const& string, const SubstringLocation& buffer)
     {
         if (buffer.baseString->is8Bit())
             return WTF::equal(string, buffer.baseString->characters8() + buffer.start, buffer.length);
         return WTF::equal(string, buffer.baseString->characters16() + buffer.start, buffer.length);
     }

     static void translate(StringImpl*& location, const SubstringLocation& buffer, unsigned hash)
     {
         location = buffer.baseString->substring(buffer.start, buffer.length).leakRef();
         location->setHash(hash);
         location->setIsAtomic(true);
     }
 };

 PassRefPtr<StringImpl> AtomicString::add(StringImpl* baseString, unsigned start, unsigned length)
 {
     if (!baseString)
         return nullptr;

     if (!length || start >= baseString->length())
         return StringImpl::empty();

     unsigned maxLength = baseString->length() - start;
     if (length >= maxLength) {
         if (!start)
             return add(baseString);
         length = maxLength;
     }

     SubstringLocation buffer = { baseString, start, length };
     return addToStringTable<SubstringLocation, SubstringTranslator>(buffer);
 }

 typedef HashTranslatorCharBuffer<LChar> LCharBuffer;
 struct LCharBufferTranslator {
     static unsigned hash(const LCharBuffer& buf)
     {
         return StringHasher::computeHashAndMaskTop8Bits(buf.s, buf.length);
     }

     static bool equal(StringImpl* const& str, const LCharBuffer& buf)
     {
         return WTF::equal(str, buf.s, buf.length);
     }

     static void translate(StringImpl*& location, const LCharBuffer& buf, unsigned hash)
     {
         location = StringImpl::create(buf.s, buf.length).leakRef();
         location->setHash(hash);
         location->setIsAtomic(true);
     }
 };

 typedef HashTranslatorCharBuffer<char> CharBuffer;
 struct CharBufferFromLiteralDataTranslator {
     static unsigned hash(const CharBuffer& buf)
     {
         return StringHasher::computeHashAndMaskTop8Bits(reinterpret_cast<const LChar*>(buf.s), buf.length);
     }

     static bool equal(StringImpl* const& str, const CharBuffer& buf)
     {
         return WTF::equal(str, buf.s, buf.length);
     }

     static void translate(StringImpl*& location, const CharBuffer& buf, unsigned hash)
     {
         location = StringImpl::create(buf.s, buf.length).leakRef();
         location->setHash(hash);
         location->setIsAtomic(true);
     }
 };

 PassRefPtr<StringImpl> AtomicString::add(const LChar* s, unsigned length)
 {
     if (!s)
         return nullptr;

     if (!length)
         return StringImpl::empty();

     LCharBuffer buffer = { s, length };
     return addToStringTable<LCharBuffer, LCharBufferTranslator>(buffer);
 }

 PassRefPtr<StringImpl> AtomicString::addFromLiteralData(const char* characters, unsigned length)
 {
     ASSERT(characters);
     ASSERT(length);

     CharBuffer buffer = { characters, length };
     return addToStringTable<CharBuffer, CharBufferFromLiteralDataTranslator>(buffer);
 }

 PassRefPtr<StringImpl> AtomicString::addSlowCase(StringImpl* string)
 {
     return atomicStringTable().addStringImpl(string);
 }

 template<typename CharacterType>
 static inline HashSet<StringImpl*>::iterator findString(const StringImpl* stringImpl)
 {
     HashAndCharacters<CharacterType> buffer = { stringImpl->existingHash(), stringImpl->getCharacters<CharacterType>(), stringImpl->length() };
     return atomicStrings().find<HashAndCharactersTranslator<CharacterType>>(buffer);
 }

 StringImpl* AtomicString::find(const StringImpl* stringImpl)
 {
     ASSERT(stringImpl);
     ASSERT(stringImpl->existingHash());

     if (!stringImpl->length())
         return StringImpl::empty();

     HashSet<StringImpl*>::iterator iterator;
     if (stringImpl->is8Bit())
         iterator = findString<LChar>(stringImpl);
     else
         iterator = findString<UChar>(stringImpl);
     if (iterator == atomicStrings().end())
         return 0;
     return *iterator;
 }

 void AtomicString::remove(StringImpl* r)
 {
     HashSet<StringImpl*>::iterator iterator;
     if (r->is8Bit())
         iterator = findString<LChar>(r);
     else
         iterator = findString<UChar>(r);
     RELEASE_ASSERT(iterator != atomicStrings().end());
     atomicStrings().remove(iterator);
 }

 AtomicString AtomicString::lower() const
 {
     // Note: This is a hot function in the Dromaeo benchmark.
     StringImpl* impl = this->impl();
     if (UNLIKELY(!impl))
         return *this;
     RefPtr<StringImpl> newImpl = impl->lower();
     if (LIKELY(newImpl == impl))
         return *this;
     return AtomicString(newImpl.release());
 }

 AtomicString AtomicString::lowerASCII() const
 {
     StringImpl* impl = this->impl();
     if (UNLIKELY(!impl))
         return *this;
     RefPtr<StringImpl> newImpl = impl->lowerASCII();
     if (LIKELY(newImpl == impl))
         return *this;
     return AtomicString(newImpl.release());
 }


 AtomicString AtomicString::fromUTF8Internal(const char* charactersStart, const char* charactersEnd)
 {
     HashAndUTF8Characters buffer;
     buffer.characters = charactersStart;
     buffer.hash = calculateStringHashAndLengthFromUTF8MaskingTop8Bits(charactersStart, charactersEnd, buffer.length, buffer.utf16Length);

     if (!buffer.hash)
         return nullAtom;

     AtomicString atomicString;
     atomicString.m_string = addToStringTable<HashAndUTF8Characters, HashAndUTF8CharactersTranslator>(buffer);
     return atomicString;
 }

 template<typename IntegerType>
 static AtomicString integerToAtomicString(IntegerType input)
 {
     IntegerToStringConverter<IntegerType> converter(input);
     return AtomicString(converter.characters8(), converter.length());
 }

 AtomicString AtomicString::number(int number)
 {
     return integerToAtomicString(number);
 }

 AtomicString AtomicString::number(unsigned number)
 {
     return integerToAtomicString(number);
 }

 AtomicString AtomicString::number(long number)
 {
     return integerToAtomicString(number);
 }

 AtomicString AtomicString::number(unsigned long number)
 {
     return integerToAtomicString(number);
 }

 AtomicString AtomicString::number(long long number)
 {
     return integerToAtomicString(number);
 }

 AtomicString AtomicString::number(unsigned long long number)
 {
     return integerToAtomicString(number);
 }

 AtomicString AtomicString::number(double number, unsigned precision, TrailingZerosTruncatingPolicy trailingZerosTruncatingPolicy)
 {
     NumberToStringBuffer buffer;
     return AtomicString(numberToFixedPrecisionString(number, precision, buffer, trailingZerosTruncatingPolicy == TruncateTrailingZeros));
 }

 std::ostream& operator<<(std::ostream& out, const AtomicString& s)
 {
     return out << s.getString();
 }

 #ifndef NDEBUG
 void AtomicString::show() const
 {
     m_string.show();
 }
 #endif

 } // namespace WTF
	/*
	* Copyright (C) 2004, 2005, 2006, 2007, 2008, 2013 Apple Inc. All rights reserved.
	* Copyright (C) 2010 Patrick Gansterer <[email protected]>
	* Copyright (C) 2012 Google Inc. All rights reserved.
	*
	* This library is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Library General Public
	* License as published by the Free Software Foundation; either
	* version 2 of the License, or (at your option) any later version.
	*
	* This library is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* Library General Public License for more details.
	*
	* You should have received a copy of the GNU Library General Public License
	* along with this library; see the file COPYING.LIB. If not, write to
	* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
	* Boston, MA 02110-1301, USA.
	*
	*/

	#include "wtf/text/AtomicString.h"

	#include "wtf/HashSet.h"
	#include "wtf/WTFThreadData.h"
	#include "wtf/dtoa.h"
	#include "wtf/text/IntegerToStringConversion.h"
	#include "wtf/text/StringHash.h"
	#include "wtf/text/UTF8.h"

	namespace WTF {

	using namespace Unicode;

	static_assert(sizeof(AtomicString) == sizeof(String), "AtomicString and String must be same size");

	class AtomicStringTable {
	USING_FAST_MALLOC(AtomicStringTable);
	WTF_MAKE_NONCOPYABLE(AtomicStringTable);
	public:
	static AtomicStringTable* create(WTFThreadData& data)
	{
	data.m_atomicStringTable = new AtomicStringTable;
	data.m_atomicStringTableDestructor = AtomicStringTable::destroy;
	data.m_atomicStringTable->addStaticStrings();
	return data.m_atomicStringTable;
	}

	StringImpl* addStringImpl(StringImpl* string)
	{
	if (!string->length())
	return StringImpl::empty();

	StringImpl* result = *m_table.add(string).storedValue;

	if (!result->isAtomic())
	result->setIsAtomic(true);

	ASSERT(!string->isStatic() \|\| result->isStatic());
	return result;
	}

	HashSet<StringImpl*>& table()
	{
	return m_table;
	}

	private:
	AtomicStringTable() { }

	void addStaticStrings()
	{
	const StaticStringsTable& staticStrings = StringImpl::allStaticStrings();

	StaticStringsTable::const_iterator it = staticStrings.begin();
	for (; it != staticStrings.end(); ++it) {
	addStringImpl(it->value);
	}
	}

	static void destroy(AtomicStringTable* table)
	{
	HashSet<StringImpl*>::iterator end = table->m_table.end();
	for (HashSet<StringImpl*>::iterator iter = table->m_table.begin(); iter != end; ++iter) {
	StringImpl* string = *iter;
	if (!string->isStatic()) {
	ASSERT(string->isAtomic());
	string->setIsAtomic(false);
	}
	}
	delete table;
	}

	HashSet<StringImpl*> m_table;
	};

	static inline AtomicStringTable& atomicStringTable()
	{
	// Once possible we should make this non-lazy (constructed in WTFThreadData's constructor).
	WTFThreadData& data = wtfThreadData();
	AtomicStringTable* table = data.atomicStringTable();
	if (UNLIKELY(!table))
	table = AtomicStringTable::create(data);
	return *table;
	}

	static inline HashSet<StringImpl*>& atomicStrings()
	{
	return atomicStringTable().table();
	}

	void AtomicString::reserveTableCapacity(size_t size)
	{
	atomicStringTable().table().reserveCapacityForSize(size);
	}

	template<typename T, typename HashTranslator>
	static inline PassRefPtr<StringImpl> addToStringTable(const T& value)
	{
	HashSet<StringImpl*>::AddResult addResult = atomicStrings().addWithTranslator<HashTranslator>(value);

	// If the string is newly-translated, then we need to adopt it.
	// The boolean in the pair tells us if that is so.
	return addResult.isNewEntry ? adoptRef(addResult.storedValue) : addResult.storedValue;
	}

	PassRefPtr<StringImpl> AtomicString::add(const LChar* c)
	{
	if (!c)
	return nullptr;
	if (!*c)
	return StringImpl::empty();

	return add(c, strlen(reinterpret_cast<const char*>(c)));
	}

	template<typename CharacterType>
	struct HashTranslatorCharBuffer {
	const CharacterType* s;
	unsigned length;
	};

	typedef HashTranslatorCharBuffer<UChar> UCharBuffer;
	struct UCharBufferTranslator {
	static unsigned hash(const UCharBuffer& buf)
	{
	return StringHasher::computeHashAndMaskTop8Bits(buf.s, buf.length);
	}

	static bool equal(StringImpl* const& str, const UCharBuffer& buf)
	{
	return WTF::equal(str, buf.s, buf.length);
	}

	static void translate(StringImpl*& location, const UCharBuffer& buf, unsigned hash)
	{
	location = StringImpl::create8BitIfPossible(buf.s, buf.length).leakRef();
	location->setHash(hash);
	location->setIsAtomic(true);
	}
	};

	template<typename CharacterType>
	struct HashAndCharacters {
	unsigned hash;
	const CharacterType* characters;
	unsigned length;
	};

	template<typename CharacterType>
	struct HashAndCharactersTranslator {
	static unsigned hash(const HashAndCharacters<CharacterType>& buffer)
	{
	ASSERT(buffer.hash == StringHasher::computeHashAndMaskTop8Bits(buffer.characters, buffer.length));
	return buffer.hash;
	}

	static bool equal(StringImpl* const& string, const HashAndCharacters<CharacterType>& buffer)
	{
	return WTF::equal(string, buffer.characters, buffer.length);
	}

	static void translate(StringImpl*& location, const HashAndCharacters<CharacterType>& buffer, unsigned hash)
	{
	location = StringImpl::create(buffer.characters, buffer.length).leakRef();
	location->setHash(hash);
	location->setIsAtomic(true);
	}
	};

	struct HashAndUTF8Characters {
	unsigned hash;
	const char* characters;
	unsigned length;
	unsigned utf16Length;
	};

	struct HashAndUTF8CharactersTranslator {
	static unsigned hash(const HashAndUTF8Characters& buffer)
	{
	return buffer.hash;
	}

	static bool equal(StringImpl* const& string, const HashAndUTF8Characters& buffer)
	{
	if (buffer.utf16Length != string->length())
	return false;

	// If buffer contains only ASCII characters UTF-8 and UTF16 length are the same.
	if (buffer.utf16Length != buffer.length) {
	if (string->is8Bit()) {
	const LChar* characters8 = string->characters8();
	return equalLatin1WithUTF8(characters8, characters8 + string->length(), buffer.characters, buffer.characters + buffer.length);
	}
	const UChar* characters16 = string->characters16();
	return equalUTF16WithUTF8(characters16, characters16 + string->length(), buffer.characters, buffer.characters + buffer.length);
	}

	if (string->is8Bit()) {
	const LChar* stringCharacters = string->characters8();

	for (unsigned i = 0; i < buffer.length; ++i) {
	ASSERT(isASCII(buffer.characters[i]));
	if (stringCharacters[i] != buffer.characters[i])
	return false;
	}

	return true;
	}

	const UChar* stringCharacters = string->characters16();

	for (unsigned i = 0; i < buffer.length; ++i) {
	ASSERT(isASCII(buffer.characters[i]));
	if (stringCharacters[i] != buffer.characters[i])
	return false;
	}

	return true;
	}

	static void translate(StringImpl*& location, const HashAndUTF8Characters& buffer, unsigned hash)
	{
	UChar* target;
	RefPtr<StringImpl> newString = StringImpl::createUninitialized(buffer.utf16Length, target);

	bool isAllASCII;
	const char* source = buffer.characters;
	if (convertUTF8ToUTF16(&source, source + buffer.length, &target, target + buffer.utf16Length, &isAllASCII) != conversionOK)
	ASSERT_NOT_REACHED();

	if (isAllASCII)
	newString = StringImpl::create(buffer.characters, buffer.length);

	location = newString.release().leakRef();
	location->setHash(hash);
	location->setIsAtomic(true);
	}
	};

	PassRefPtr<StringImpl> AtomicString::add(const UChar* s, unsigned length)
	{
	if (!s)
	return nullptr;

	if (!length)
	return StringImpl::empty();

	UCharBuffer buffer = { s, length };
	return addToStringTable<UCharBuffer, UCharBufferTranslator>(buffer);
	}

	PassRefPtr<StringImpl> AtomicString::add(const UChar* s, unsigned length, unsigned existingHash)
	{
	ASSERT(s);
	ASSERT(existingHash);

	if (!length)
	return StringImpl::empty();

	HashAndCharacters<UChar> buffer = { existingHash, s, length };
	return addToStringTable<HashAndCharacters<UChar>, HashAndCharactersTranslator<UChar>>(buffer);
	}

	PassRefPtr<StringImpl> AtomicString::add(const UChar* s)
	{
	if (!s)
	return nullptr;

	unsigned length = 0;
	while (s[length] != UChar(0))
	++length;

	if (!length)
	return StringImpl::empty();

	UCharBuffer buffer = { s, length };
	return addToStringTable<UCharBuffer, UCharBufferTranslator>(buffer);
	}

	struct SubstringLocation {
	StringImpl* baseString;
	unsigned start;
	unsigned length;
	};

	struct SubstringTranslator {
	static unsigned hash(const SubstringLocation& buffer)
	{
	if (buffer.baseString->is8Bit())
	return StringHasher::computeHashAndMaskTop8Bits(buffer.baseString->characters8() + buffer.start, buffer.length);
	return StringHasher::computeHashAndMaskTop8Bits(buffer.baseString->characters16() + buffer.start, buffer.length);
	}

	static bool equal(StringImpl* const& string, const SubstringLocation& buffer)
	{
	if (buffer.baseString->is8Bit())
	return WTF::equal(string, buffer.baseString->characters8() + buffer.start, buffer.length);
	return WTF::equal(string, buffer.baseString->characters16() + buffer.start, buffer.length);
	}

	static void translate(StringImpl*& location, const SubstringLocation& buffer, unsigned hash)
	{
	location = buffer.baseString->substring(buffer.start, buffer.length).leakRef();
	location->setHash(hash);
	location->setIsAtomic(true);
	}
	};

	PassRefPtr<StringImpl> AtomicString::add(StringImpl* baseString, unsigned start, unsigned length)
	{
	if (!baseString)
	return nullptr;

	if (!length \|\| start >= baseString->length())
	return StringImpl::empty();

	unsigned maxLength = baseString->length() - start;
	if (length >= maxLength) {
	if (!start)
	return add(baseString);
	length = maxLength;
	}

	SubstringLocation buffer = { baseString, start, length };
	return addToStringTable<SubstringLocation, SubstringTranslator>(buffer);
	}

	typedef HashTranslatorCharBuffer<LChar> LCharBuffer;
	struct LCharBufferTranslator {
	static unsigned hash(const LCharBuffer& buf)
	{
	return StringHasher::computeHashAndMaskTop8Bits(buf.s, buf.length);
	}

	static bool equal(StringImpl* const& str, const LCharBuffer& buf)
	{
	return WTF::equal(str, buf.s, buf.length);
	}

	static void translate(StringImpl*& location, const LCharBuffer& buf, unsigned hash)
	{
	location = StringImpl::create(buf.s, buf.length).leakRef();
	location->setHash(hash);
	location->setIsAtomic(true);
	}
	};

	typedef HashTranslatorCharBuffer<char> CharBuffer;
	struct CharBufferFromLiteralDataTranslator {
	static unsigned hash(const CharBuffer& buf)
	{
	return StringHasher::computeHashAndMaskTop8Bits(reinterpret_cast<const LChar*>(buf.s), buf.length);
	}

	static bool equal(StringImpl* const& str, const CharBuffer& buf)
	{
	return WTF::equal(str, buf.s, buf.length);
	}

	static void translate(StringImpl*& location, const CharBuffer& buf, unsigned hash)
	{
	location = StringImpl::create(buf.s, buf.length).leakRef();
	location->setHash(hash);
	location->setIsAtomic(true);
	}
	};

	PassRefPtr<StringImpl> AtomicString::add(const LChar* s, unsigned length)
	{
	if (!s)
	return nullptr;

	if (!length)
	return StringImpl::empty();

	LCharBuffer buffer = { s, length };
	return addToStringTable<LCharBuffer, LCharBufferTranslator>(buffer);
	}

	PassRefPtr<StringImpl> AtomicString::addFromLiteralData(const char* characters, unsigned length)
	{
	ASSERT(characters);
	ASSERT(length);

	CharBuffer buffer = { characters, length };
	return addToStringTable<CharBuffer, CharBufferFromLiteralDataTranslator>(buffer);
	}

	PassRefPtr<StringImpl> AtomicString::addSlowCase(StringImpl* string)
	{
	return atomicStringTable().addStringImpl(string);
	}

	template<typename CharacterType>
	static inline HashSet<StringImpl>::iterator findString(const StringImpl stringImpl)
	{
	HashAndCharacters<CharacterType> buffer = { stringImpl->existingHash(), stringImpl->getCharacters<CharacterType>(), stringImpl->length() };
	return atomicStrings().find<HashAndCharactersTranslator<CharacterType>>(buffer);
	}

	StringImpl* AtomicString::find(const StringImpl* stringImpl)
	{
	ASSERT(stringImpl);
	ASSERT(stringImpl->existingHash());

	if (!stringImpl->length())
	return StringImpl::empty();

	HashSet<StringImpl*>::iterator iterator;
	if (stringImpl->is8Bit())
	iterator = findString<LChar>(stringImpl);
	else
	iterator = findString<UChar>(stringImpl);
	if (iterator == atomicStrings().end())
	return 0;
	return *iterator;
	}

	void AtomicString::remove(StringImpl* r)
	{
	HashSet<StringImpl*>::iterator iterator;
	if (r->is8Bit())
	iterator = findString<LChar>(r);
	else
	iterator = findString<UChar>(r);
	RELEASE_ASSERT(iterator != atomicStrings().end());
	atomicStrings().remove(iterator);
	}

	AtomicString AtomicString::lower() const
	{
	// Note: This is a hot function in the Dromaeo benchmark.
	StringImpl* impl = this->impl();
	if (UNLIKELY(!impl))
	return *this;
	RefPtr<StringImpl> newImpl = impl->lower();
	if (LIKELY(newImpl == impl))
	return *this;
	return AtomicString(newImpl.release());
	}

	AtomicString AtomicString::lowerASCII() const
	{
	StringImpl* impl = this->impl();
	if (UNLIKELY(!impl))
	return *this;
	RefPtr<StringImpl> newImpl = impl->lowerASCII();
	if (LIKELY(newImpl == impl))
	return *this;
	return AtomicString(newImpl.release());
	}


	AtomicString AtomicString::fromUTF8Internal(const char* charactersStart, const char* charactersEnd)
	{
	HashAndUTF8Characters buffer;
	buffer.characters = charactersStart;
	buffer.hash = calculateStringHashAndLengthFromUTF8MaskingTop8Bits(charactersStart, charactersEnd, buffer.length, buffer.utf16Length);

	if (!buffer.hash)
	return nullAtom;

	AtomicString atomicString;
	atomicString.m_string = addToStringTable<HashAndUTF8Characters, HashAndUTF8CharactersTranslator>(buffer);
	return atomicString;
	}

	template<typename IntegerType>
	static AtomicString integerToAtomicString(IntegerType input)
	{
	IntegerToStringConverter<IntegerType> converter(input);
	return AtomicString(converter.characters8(), converter.length());
	}

	AtomicString AtomicString::number(int number)
	{
	return integerToAtomicString(number);
	}

	AtomicString AtomicString::number(unsigned number)
	{
	return integerToAtomicString(number);
	}

	AtomicString AtomicString::number(long number)
	{
	return integerToAtomicString(number);
	}

	AtomicString AtomicString::number(unsigned long number)
	{
	return integerToAtomicString(number);
	}

	AtomicString AtomicString::number(long long number)
	{
	return integerToAtomicString(number);
	}

	AtomicString AtomicString::number(unsigned long long number)
	{
	return integerToAtomicString(number);
	}

	AtomicString AtomicString::number(double number, unsigned precision, TrailingZerosTruncatingPolicy trailingZerosTruncatingPolicy)
	{
	NumberToStringBuffer buffer;
	return AtomicString(numberToFixedPrecisionString(number, precision, buffer, trailingZerosTruncatingPolicy == TruncateTrailingZeros));
	}

	std::ostream& operator<<(std::ostream& out, const AtomicString& s)
	{
	return out << s.getString();
	}

	#ifndef NDEBUG
	void AtomicString::show() const
	{
	m_string.show();
	}
	#endif

	} // namespace WTF