#ifndef StringImpl_h

#define StringImpl_h

#include <limits.h>

#include <unicode/uchar.h>

#include <unicode/ustring.h>

#include <wtf/ASCIICType.h>

#include <wtf/Forward.h>

#include <wtf/MathExtras.h>

#include <wtf/StdLibExtras.h>

#include <wtf/StringHasher.h>

#include <wtf/Vector.h>

#include <wtf/text/ConversionMode.h>

#if USE(CF)

typedef const struct __CFString * CFStringRef;

#endif

#ifdef __OBJC__

@class NSString;

#endif

namespace JSC {

namespace LLInt { class Data; }

class LLIntOffsetsExtractor;

}

namespace WTF {

struct CStringTranslator;

template<typename CharacterType> struct HashAndCharactersTranslator;

struct HashAndUTF8CharactersTranslator;

struct LCharBufferTranslator;

struct CharBufferFromLiteralDataTranslator;

struct SubstringTranslator;

struct UCharBufferTranslator;

template<typename> class RetainPtr;

enum TextCaseSensitivity {

TextCaseSensitive,

TextCaseInsensitive

};

typedef bool (*CharacterMatchFunctionPtr)(UChar);

typedef bool (*IsWhiteSpaceFunctionPtr)(UChar);

#undef STRING_STATS

#ifdef STRING_STATS

struct StringStats {

inline void add8BitString(unsigned length, bool isSubString = false)

{

++m_totalNumberStrings;

++m_number8BitStrings;

if (!isSubString)

m_total8BitData += length;

}

inline void add16BitString(unsigned length, bool isSubString = false)

{

++m_totalNumberStrings;

++m_number16BitStrings;

if (!isSubString)

m_total16BitData += length;

}

inline void addUpconvertedString(unsigned length)

{

++m_numberUpconvertedStrings;

m_totalUpconvertedData += length;

}

void removeString(StringImpl*);

void printStats();

static const unsigned s_printStringStatsFrequency = 5000;

static unsigned s_stringRemovesTillPrintStats;

unsigned m_totalNumberStrings;

unsigned m_number8BitStrings;

unsigned m_number16BitStrings;

unsigned m_numberUpconvertedStrings;

unsigned long long m_total8BitData;

unsigned long long m_total16BitData;

unsigned long long m_totalUpconvertedData;

};

#define STRING_STATS_ADD_8BIT_STRING(length) StringImpl::stringStats().add8BitString(length)

#define STRING_STATS_ADD_8BIT_STRING2(length, isSubString) StringImpl::stringStats().add8BitString(length, isSubString)

#define STRING_STATS_ADD_16BIT_STRING(length) StringImpl::stringStats().add16BitString(length)

#define STRING_STATS_ADD_16BIT_STRING2(length, isSubString) StringImpl::stringStats().add16BitString(length, isSubString)

#define STRING_STATS_ADD_UPCONVERTED_STRING(length) StringImpl::stringStats().addUpconvertedString(length)

#define STRING_STATS_REMOVE_STRING(string) StringImpl::stringStats().removeString(string)

#else

#define STRING_STATS_ADD_8BIT_STRING(length) ((void)0)

#define STRING_STATS_ADD_8BIT_STRING2(length, isSubString) ((void)0)

#define STRING_STATS_ADD_16BIT_STRING(length) ((void)0)

#define STRING_STATS_ADD_16BIT_STRING2(length, isSubString) ((void)0)

#define STRING_STATS_ADD_UPCONVERTED_STRING(length) ((void)0)

#define STRING_STATS_REMOVE_STRING(string) ((void)0)

#endif

class StringImpl {

WTF_MAKE_NONCOPYABLE(StringImpl); WTF_MAKE_FAST_ALLOCATED;

friend struct WTF::CStringTranslator;

template<typename CharacterType> friend struct WTF::HashAndCharactersTranslator;

friend struct WTF::HashAndUTF8CharactersTranslator;

friend struct WTF::CharBufferFromLiteralDataTranslator;

friend struct WTF::LCharBufferTranslator;

friend struct WTF::SubstringTranslator;

friend struct WTF::UCharBufferTranslator;

friend class AtomicStringImpl;

friend class JSC::LLInt::Data;

friend class JSC::LLIntOffsetsExtractor;

private:

enum BufferOwnership {

BufferInternal,

BufferOwned,

BufferSubstring,

};

// Used to construct static strings, which have an special refCount that can never hit zero.

// This means that the static string will never be destroyed, which is important because

// static strings will be shared across threads & ref-counted in a non-threadsafe manner.

friend class NeverDestroyed<StringImpl>;

enum ConstructEmptyStringTag { ConstructEmptyString };

StringImpl(ConstructEmptyStringTag)

: m_refCount(s_refCountFlagIsStaticString)

, m_length(0)

, m_data8(reinterpret_cast<const LChar*>(&m_length))

, m_hashAndFlags(s_hashFlag8BitBuffer | s_hashFlagIsAtomic | BufferOwned)

{

// Ensure that the hash is computed so that AtomicStringHash can call existingHash()

// with impunity. The empty string is special because it is never entered into

// AtomicString's HashKey, but still needs to compare correctly.

STRING_STATS_ADD_8BIT_STRING(m_length);

hash();

}

// FIXME: there has to be a less hacky way to do this.

enum Force8Bit { Force8BitConstructor };

// Create a normal 8-bit string with internal storage (BufferInternal)

StringImpl(unsigned length, Force8Bit)

: m_refCount(s_refCountIncrement)

, m_length(length)

, m_data8(tailPointer<LChar>())

, m_hashAndFlags(s_hashFlag8BitBuffer | BufferInternal)

{

ASSERT(m_data8);

ASSERT(m_length);

STRING_STATS_ADD_8BIT_STRING(m_length);

}

// Create a normal 16-bit string with internal storage (BufferInternal)

StringImpl(unsigned length)

: m_refCount(s_refCountIncrement)

, m_length(length)

, m_data16(tailPointer<UChar>())

, m_hashAndFlags(BufferInternal)

{

ASSERT(m_data16);

ASSERT(m_length);

STRING_STATS_ADD_16BIT_STRING(m_length);

}

// Create a StringImpl adopting ownership of the provided buffer (BufferOwned)

StringImpl(MallocPtr<LChar> characters, unsigned length)

: m_refCount(s_refCountIncrement)

, m_length(length)

, m_data8(characters.leakPtr())

, m_hashAndFlags(s_hashFlag8BitBuffer | BufferOwned)

{

ASSERT(m_data8);

ASSERT(m_length);

STRING_STATS_ADD_8BIT_STRING(m_length);

}

enum ConstructWithoutCopyingTag { ConstructWithoutCopying };

StringImpl(const UChar* characters, unsigned length, ConstructWithoutCopyingTag)

: m_refCount(s_refCountIncrement)

, m_length(length)

, m_data16(characters)

, m_hashAndFlags(BufferInternal)

{

ASSERT(m_data16);

ASSERT(m_length);

STRING_STATS_ADD_16BIT_STRING(0);

}

StringImpl(const LChar* characters, unsigned length, ConstructWithoutCopyingTag)

: m_refCount(s_refCountIncrement)

, m_length(length)

, m_data8(characters)

, m_hashAndFlags(s_hashFlag8BitBuffer | BufferInternal)

{

ASSERT(m_data8);

ASSERT(m_length);

STRING_STATS_ADD_8BIT_STRING(0);

}

// Create a StringImpl adopting ownership of the provided buffer (BufferOwned)

StringImpl(MallocPtr<UChar> characters, unsigned length)

: m_refCount(s_refCountIncrement)

, m_length(length)

, m_data16(characters.leakPtr())

, m_hashAndFlags(BufferOwned)

{

ASSERT(m_data16);

ASSERT(m_length);

STRING_STATS_ADD_16BIT_STRING(m_length);

}

// Used to create new strings that are a substring of an existing 8-bit StringImpl (BufferSubstring)

StringImpl(const LChar* characters, unsigned length, PassRefPtr<StringImpl> base)

: m_refCount(s_refCountIncrement)

, m_length(length)

, m_data8(characters)

, m_hashAndFlags(s_hashFlag8BitBuffer | BufferSubstring)

{

ASSERT(is8Bit());

ASSERT(m_data8);

ASSERT(m_length);

ASSERT(base->bufferOwnership() != BufferSubstring);

substringBuffer() = base.leakRef();

STRING_STATS_ADD_8BIT_STRING2(m_length, true);

}

// Used to create new strings that are a substring of an existing 16-bit StringImpl (BufferSubstring)

StringImpl(const UChar* characters, unsigned length, PassRefPtr<StringImpl> base)

: m_refCount(s_refCountIncrement)

, m_length(length)

, m_data16(characters)

, m_hashAndFlags(BufferSubstring)

{

ASSERT(!is8Bit());

ASSERT(m_data16);

ASSERT(m_length);

ASSERT(base->bufferOwnership() != BufferSubstring);

substringBuffer() = base.leakRef();

STRING_STATS_ADD_16BIT_STRING2(m_length, true);

}

enum CreateEmptyUniqueTag { CreateEmptyUnique };

StringImpl(CreateEmptyUniqueTag)

: m_refCount(s_refCountIncrement)

, m_length(0)

// We expect m_length to be initialized to 0 as we use it

// to represent a null terminated buffer.

, m_data8(reinterpret_cast<const LChar*>(&m_length))

, m_hashAndFlags(hashAndFlagsForEmptyUnique())

{

ASSERT(m_data8);

STRING_STATS_ADD_8BIT_STRING(m_length);

}

~StringImpl();

public:

WTF_EXPORT_STRING_API static void destroy(StringImpl*);

WTF_EXPORT_STRING_API static PassRef<StringImpl> create(const UChar*, unsigned length);

WTF_EXPORT_STRING_API static PassRef<StringImpl> create(const LChar*, unsigned length);

WTF_EXPORT_STRING_API static PassRef<StringImpl> create8BitIfPossible(const UChar*, unsigned length);

template<size_t inlineCapacity>

static PassRef<StringImpl> create8BitIfPossible(const Vector<UChar, inlineCapacity>& vector)

{

return create8BitIfPossible(vector.data(), vector.size());

}

WTF_EXPORT_STRING_API static PassRef<StringImpl> create8BitIfPossible(const UChar*);

ALWAYS_INLINE static PassRef<StringImpl> create(const char* s, unsigned length) { return create(reinterpret_cast<const LChar*>(s), length); }

WTF_EXPORT_STRING_API static PassRef<StringImpl> create(const LChar*);

ALWAYS_INLINE static PassRef<StringImpl> create(const char* s) { return create(reinterpret_cast<const LChar*>(s)); }

static ALWAYS_INLINE PassRef<StringImpl> createSubstringSharingImpl8(PassRefPtr<StringImpl> rep, unsigned offset, unsigned length)

{

ASSERT(rep);

ASSERT(length <= rep->length());

if (!length)

return *empty();

ASSERT(rep->is8Bit());

StringImpl* ownerRep = (rep->bufferOwnership() == BufferSubstring) ? rep->substringBuffer() : rep.get();

// We allocate a buffer that contains both the StringImpl struct as well as the pointer to the owner string.

StringImpl* stringImpl = static_cast<StringImpl*>(fastMalloc(allocationSize<StringImpl*>(1)));

return adoptRef(*new (NotNull, stringImpl) StringImpl(rep->m_data8 + offset, length, ownerRep));

}

static ALWAYS_INLINE PassRef<StringImpl> createSubstringSharingImpl(PassRefPtr<StringImpl> rep, unsigned offset, unsigned length)

{

ASSERT(rep);

ASSERT(length <= rep->length());

if (!length)

return *empty();

StringImpl* ownerRep = (rep->bufferOwnership() == BufferSubstring) ? rep->substringBuffer() : rep.get();

// We allocate a buffer that contains both the StringImpl struct as well as the pointer to the owner string.

StringImpl* stringImpl = static_cast<StringImpl*>(fastMalloc(allocationSize<StringImpl*>(1)));

if (rep->is8Bit())

return adoptRef(*new (NotNull, stringImpl) StringImpl(rep->m_data8 + offset, length, ownerRep));

return adoptRef(*new (NotNull, stringImpl) StringImpl(rep->m_data16 + offset, length, ownerRep));

}

template<unsigned charactersCount>

ALWAYS_INLINE static PassRef<StringImpl> createFromLiteral(const char (&characters)[charactersCount])

{

COMPILE_ASSERT(charactersCount > 1, StringImplFromLiteralNotEmpty);

COMPILE_ASSERT((charactersCount - 1 <= ((unsigned(~0) - sizeof(StringImpl)) / sizeof(LChar))), StringImplFromLiteralCannotOverflow);

return createWithoutCopying(reinterpret_cast<const LChar*>(characters), charactersCount - 1);

}

// FIXME: Transition off of these functions to createWithoutCopying instead.

WTF_EXPORT_STRING_API static PassRef<StringImpl> createFromLiteral(const char* characters, unsigned length);

WTF_EXPORT_STRING_API static PassRef<StringImpl> createFromLiteral(const char* characters);

WTF_EXPORT_STRING_API static PassRef<StringImpl> createWithoutCopying(const UChar* characters, unsigned length);

WTF_EXPORT_STRING_API static PassRef<StringImpl> createWithoutCopying(const LChar* characters, unsigned length);

WTF_EXPORT_STRING_API static PassRef<StringImpl> createUninitialized(unsigned length, LChar*& data);

WTF_EXPORT_STRING_API static PassRef<StringImpl> createUninitialized(unsigned length, UChar*& data);

template <typename T> static ALWAYS_INLINE PassRefPtr<StringImpl> tryCreateUninitialized(unsigned length, T*& output)

{

if (!length) {

output = 0;

return empty();

}

if (length > ((std::numeric_limits<unsigned>::max() - sizeof(StringImpl)) / sizeof(T))) {

output = 0;

return 0;

}

StringImpl* resultImpl;

if (!tryFastMalloc(allocationSize<T>(length)).getValue(resultImpl)) {

output = 0;

return 0;

}

output = resultImpl->tailPointer<T>();

return constructInternal<T>(resultImpl, length);

}

static PassRef<StringImpl> createEmptyUnique()

{

return adoptRef(*new StringImpl(CreateEmptyUnique));

}

// Reallocate the StringImpl. The originalString must be only owned by the PassRefPtr,

// and the buffer ownership must be BufferInternal. Just like the input pointer of realloc(),

// the originalString can't be used after this function.

static PassRef<StringImpl> reallocate(PassRefPtr<StringImpl> originalString, unsigned length, LChar*& data);

static PassRef<StringImpl> reallocate(PassRefPtr<StringImpl> originalString, unsigned length, UChar*& data);

static unsigned flagsOffset() { return OBJECT_OFFSETOF(StringImpl, m_hashAndFlags); }

static unsigned flagIs8Bit() { return s_hashFlag8BitBuffer; }

static unsigned flagIsAtomic() { return s_hashFlagIsAtomic; }

static unsigned dataOffset() { return OBJECT_OFFSETOF(StringImpl, m_data8); }

template<typename CharType, size_t inlineCapacity, typename OverflowHandler>

static PassRef<StringImpl> adopt(Vector<CharType, inlineCapacity, OverflowHandler>& vector)

{

if (size_t size = vector.size()) {

ASSERT(vector.data());

if (size > std::numeric_limits<unsigned>::max())

CRASH();

return adoptRef(*new StringImpl(vector.releaseBuffer(), size));

}

return *empty();

}

WTF_EXPORT_STRING_API static PassRef<StringImpl> adopt(StringBuffer<UChar>&);

WTF_EXPORT_STRING_API static PassRef<StringImpl> adopt(StringBuffer<LChar>&);

unsigned length() const { return m_length; }

bool is8Bit() const { return m_hashAndFlags & s_hashFlag8BitBuffer; }

ALWAYS_INLINE const LChar* characters8() const { ASSERT(is8Bit()); return m_data8; }

ALWAYS_INLINE const UChar* characters16() const { ASSERT(!is8Bit()); return m_data16; }

template <typename CharType>

ALWAYS_INLINE const CharType *characters() const;

size_t cost() const

{

// For substrings, return the cost of the base string.

if (bufferOwnership() == BufferSubstring)

return substringBuffer()->cost();

if (m_hashAndFlags & s_hashFlagDidReportCost)

return 0;

m_hashAndFlags |= s_hashFlagDidReportCost;

size_t result = m_length;

if (!is8Bit())

result <<= 1;

return result;

}

size_t costDuringGC()

{

if (isStatic())

return 0;

if (bufferOwnership() == BufferSubstring)

return divideRoundedUp(substringBuffer()->costDuringGC(), refCount());

size_t result = m_length;

if (!is8Bit())

result <<= 1;

return divideRoundedUp(result, refCount());

}

WTF_EXPORT_STRING_API size_t sizeInBytes() const;

bool isEmptyUnique() const

{

return !length() && !isStatic();

}

bool isAtomic() const { return m_hashAndFlags & s_hashFlagIsAtomic; }

void setIsAtomic(bool isAtomic)

{

ASSERT(!isStatic());

ASSERT(!isEmptyUnique());

if (isAtomic)

m_hashAndFlags |= s_hashFlagIsAtomic;

else

m_hashAndFlags &= ~s_hashFlagIsAtomic;

}

#ifdef STRING_STATS

bool isSubString() const { return bufferOwnership() == BufferSubstring; }

#endif

static WTF_EXPORT_STRING_API CString utf8ForCharacters(const UChar* characters, unsigned length, ConversionMode = LenientConversion);

WTF_EXPORT_STRING_API CString utf8ForRange(unsigned offset, unsigned length, ConversionMode = LenientConversion) const;

WTF_EXPORT_STRING_API CString utf8(ConversionMode = LenientConversion) const;

private:

static WTF_EXPORT_STRING_API bool utf8Impl(const UChar* characters, unsigned length, char*& buffer, size_t bufferSize, ConversionMode);

// The high bits of 'hash' are always empty, but we prefer to store our flags

// in the low bits because it makes them slightly more efficient to access.

// So, we shift left and right when setting and getting our hash code.

void setHash(unsigned hash) const

{

ASSERT(!hasHash());

// Multiple clients assume that StringHasher is the canonical string hash function.

ASSERT(hash == (is8Bit() ? StringHasher::computeHashAndMaskTop8Bits(m_data8, m_length) : StringHasher::computeHashAndMaskTop8Bits(m_data16, m_length)));

ASSERT(!(hash & (s_flagMask << (8 * sizeof(hash) - s_flagCount)))); // Verify that enough high bits are empty.

hash <<= s_flagCount;

ASSERT(!(hash & m_hashAndFlags)); // Verify that enough low bits are empty after shift.

ASSERT(hash); // Verify that 0 is a valid sentinel hash value.

m_hashAndFlags |= hash; // Store hash with flags in low bits.

}

unsigned rawHash() const

{

return m_hashAndFlags >> s_flagCount;

}

public:

bool hasHash() const

{

return rawHash() != 0;

}

unsigned existingHash() const

{

ASSERT(hasHash());

return rawHash();

}

unsigned hash() const

{

if (hasHash())

return existingHash();

return hashSlowCase();

}

bool isStatic() const { return m_refCount & s_refCountFlagIsStaticString; }

inline size_t refCount() const

{

return m_refCount / s_refCountIncrement;

}

inline bool hasOneRef() const

{

return m_refCount == s_refCountIncrement;

}

// This method is useful for assertions.

inline bool hasAtLeastOneRef() const

{

return !!m_refCount;

}

inline void ref()

{

ASSERT(!isCompilationThread());

m_refCount += s_refCountIncrement;

}

inline void deref()

{

ASSERT(!isCompilationThread());

unsigned tempRefCount = m_refCount - s_refCountIncrement;

if (!tempRefCount) {

StringImpl::destroy(this);

return;

}

m_refCount = tempRefCount;

}

WTF_EXPORT_PRIVATE static StringImpl* empty();

// FIXME: Does this really belong in StringImpl?

template <typename T> static void copyChars(T* destination, const T* source, unsigned numCharacters)

{

if (numCharacters == 1) {

*destination = *source;

return;

}

if (numCharacters <= s_copyCharsInlineCutOff) {

unsigned i = 0;

#if (CPU(X86) || CPU(X86_64))

const unsigned charsPerInt = sizeof(uint32_t) / sizeof(T);

if (numCharacters > charsPerInt) {

unsigned stopCount = numCharacters & ~(charsPerInt - 1);

const uint32_t* srcCharacters = reinterpret_cast<const uint32_t*>(source);

uint32_t* destCharacters = reinterpret_cast<uint32_t*>(destination);

for (unsigned j = 0; i < stopCount; i += charsPerInt, ++j)

destCharacters[j] = srcCharacters[j];

}

#endif

for (; i < numCharacters; ++i)

destination[i] = source[i];

} else

memcpy(destination, source, numCharacters * sizeof(T));

}

ALWAYS_INLINE static void copyChars(UChar* destination, const LChar* source, unsigned numCharacters)

{

for (unsigned i = 0; i < numCharacters; ++i)

destination[i] = source[i];

}

// Some string features, like refcounting and the atomicity flag, are not

// thread-safe. We achieve thread safety by isolation, giving each thread

// its own copy of the string.

PassRef<StringImpl> isolatedCopy() const;

WTF_EXPORT_STRING_API PassRef<StringImpl> substring(unsigned pos, unsigned len = UINT_MAX);

UChar at(unsigned i) const

{

ASSERT_WITH_SECURITY_IMPLICATION(i < m_length);

if (is8Bit())

return m_data8[i];

return m_data16[i];

}

UChar operator[](unsigned i) const { return at(i); }

WTF_EXPORT_STRING_API UChar32 characterStartingAt(unsigned);

WTF_EXPORT_STRING_API bool containsOnlyWhitespace();

int toIntStrict(bool* ok = 0, int base = 10);

unsigned toUIntStrict(bool* ok = 0, int base = 10);

int64_t toInt64Strict(bool* ok = 0, int base = 10);

uint64_t toUInt64Strict(bool* ok = 0, int base = 10);

intptr_t toIntPtrStrict(bool* ok = 0, int base = 10);

WTF_EXPORT_STRING_API int toInt(bool* ok = 0); // ignores trailing garbage

unsigned toUInt(bool* ok = 0); // ignores trailing garbage

int64_t toInt64(bool* ok = 0); // ignores trailing garbage

uint64_t toUInt64(bool* ok = 0); // ignores trailing garbage

intptr_t toIntPtr(bool* ok = 0); // ignores trailing garbage

// FIXME: Like the strict functions above, these give false for "ok" when there is trailing garbage.

// Like the non-strict functions above, these return the value when there is trailing garbage.

// It would be better if these were more consistent with the above functions instead.

double toDouble(bool* ok = 0);

float toFloat(bool* ok = 0);

WTF_EXPORT_STRING_API PassRef<StringImpl> convertToASCIILowercase();

WTF_EXPORT_STRING_API PassRef<StringImpl> lower();

WTF_EXPORT_STRING_API PassRef<StringImpl> upper();

WTF_EXPORT_STRING_API PassRef<StringImpl> lower(const AtomicString& localeIdentifier);

WTF_EXPORT_STRING_API PassRef<StringImpl> upper(const AtomicString& localeIdentifier);

WTF_EXPORT_STRING_API PassRef<StringImpl> fill(UChar);

// FIXME: Do we need fill(char) or can we just do the right thing if UChar is ASCII?

PassRef<StringImpl> foldCase();

PassRef<StringImpl> stripWhiteSpace();

PassRef<StringImpl> stripWhiteSpace(IsWhiteSpaceFunctionPtr);

WTF_EXPORT_STRING_API PassRef<StringImpl> simplifyWhiteSpace();

PassRef<StringImpl> simplifyWhiteSpace(IsWhiteSpaceFunctionPtr);

PassRef<StringImpl> removeCharacters(CharacterMatchFunctionPtr);

template <typename CharType>

ALWAYS_INLINE PassRef<StringImpl> removeCharacters(const CharType* characters, CharacterMatchFunctionPtr);

size_t find(LChar character, unsigned start = 0);

size_t find(char character, unsigned start = 0);

size_t find(UChar character, unsigned start = 0);

WTF_EXPORT_STRING_API size_t find(CharacterMatchFunctionPtr, unsigned index = 0);

size_t find(const LChar*, unsigned index = 0);

ALWAYS_INLINE size_t find(const char* s, unsigned index = 0) { return find(reinterpret_cast<const LChar*>(s), index); }

WTF_EXPORT_STRING_API size_t find(StringImpl*);

WTF_EXPORT_STRING_API size_t find(StringImpl*, unsigned index);

size_t findIgnoringCase(const LChar*, unsigned index = 0);

ALWAYS_INLINE size_t findIgnoringCase(const char* s, unsigned index = 0) { return findIgnoringCase(reinterpret_cast<const LChar*>(s), index); }

WTF_EXPORT_STRING_API size_t findIgnoringCase(StringImpl*, unsigned index = 0);

WTF_EXPORT_STRING_API size_t findNextLineStart(unsigned index = UINT_MAX);

WTF_EXPORT_STRING_API size_t reverseFind(UChar, unsigned index = UINT_MAX);

WTF_EXPORT_STRING_API size_t reverseFind(StringImpl*, unsigned index = UINT_MAX);

WTF_EXPORT_STRING_API size_t reverseFindIgnoringCase(StringImpl*, unsigned index = UINT_MAX);

WTF_EXPORT_STRING_API bool startsWith(const StringImpl*) const;

bool startsWith(StringImpl* str, bool caseSensitive) { return caseSensitive ? startsWith(str) : (reverseFindIgnoringCase(str, 0) == 0); }

WTF_EXPORT_STRING_API bool startsWith(UChar) const;

WTF_EXPORT_STRING_API bool startsWith(const char*, unsigned matchLength, bool caseSensitive) const;

template<unsigned matchLength>

bool startsWith(const char (&prefix)[matchLength], bool caseSensitive = true) const { return startsWith(prefix, matchLength - 1, caseSensitive); }

WTF_EXPORT_STRING_API bool endsWith(StringImpl*, bool caseSensitive = true);

WTF_EXPORT_STRING_API bool endsWith(UChar) const;

WTF_EXPORT_STRING_API bool endsWith(const char*, unsigned matchLength, bool caseSensitive) const;

template<unsigned matchLength>

bool endsWith(const char (&prefix)[matchLength], bool caseSensitive = true) const { return endsWith(prefix, matchLength - 1, caseSensitive); }

WTF_EXPORT_STRING_API PassRef<StringImpl> replace(UChar, UChar);

WTF_EXPORT_STRING_API PassRef<StringImpl> replace(UChar, StringImpl*);

ALWAYS_INLINE PassRef<StringImpl> replace(UChar pattern, const char* replacement, unsigned replacementLength) { return replace(pattern, reinterpret_cast<const LChar*>(replacement), replacementLength); }

WTF_EXPORT_STRING_API PassRef<StringImpl> replace(UChar, const LChar*, unsigned replacementLength);

PassRef<StringImpl> replace(UChar, const UChar*, unsigned replacementLength);

WTF_EXPORT_STRING_API PassRef<StringImpl> replace(StringImpl*, StringImpl*);

WTF_EXPORT_STRING_API PassRef<StringImpl> replace(unsigned index, unsigned len, StringImpl*);

WTF_EXPORT_STRING_API UCharDirection defaultWritingDirection(bool* hasStrongDirectionality = nullptr);

#if USE(CF)

RetainPtr<CFStringRef> createCFString();

#endif

#ifdef __OBJC__

WTF_EXPORT_STRING_API operator NSString*();

#endif

#ifdef STRING_STATS

ALWAYS_INLINE static StringStats& stringStats() { return m_stringStats; }

#endif

WTF_EXPORT_STRING_API static const UChar latin1CaseFoldTable[256];

private:

bool requiresCopy() const

{

if (bufferOwnership() != BufferInternal)

return true;

if (is8Bit())

return m_data8 == tailPointer<LChar>();

return m_data16 == tailPointer<UChar>();

}

template<typename T>

static size_t allocationSize(unsigned tailElementCount)

{

return tailOffset<T>() + tailElementCount * sizeof(T);

}

template<typename T>

static ptrdiff_t tailOffset()

{

#if COMPILER(MSVC)

// MSVC doesn't support alignof yet.

return roundUpToMultipleOf<sizeof(T)>(sizeof(StringImpl));

#else

return roundUpToMultipleOf<alignof(T)>(offsetof(StringImpl, m_hashAndFlags) + sizeof(StringImpl::m_hashAndFlags));

#endif

}

template<typename T>

const T* tailPointer() const

{

return reinterpret_cast<const T*>(reinterpret_cast<const uint8_t*>(this) + tailOffset<T>());

}

template<typename T>

T* tailPointer()

{

return reinterpret_cast<T*>(reinterpret_cast<uint8_t*>(this) + tailOffset<T>());

}

StringImpl* const& substringBuffer() const

{

ASSERT(bufferOwnership() == BufferSubstring);

return *tailPointer<StringImpl*>();

}

StringImpl*& substringBuffer()

{

ASSERT(bufferOwnership() == BufferSubstring);

return *tailPointer<StringImpl*>();

}

// This number must be at least 2 to avoid sharing empty, null as well as 1 character strings from SmallStrings.

static const unsigned s_copyCharsInlineCutOff = 20;

BufferOwnership bufferOwnership() const { return static_cast<BufferOwnership>(m_hashAndFlags & s_hashMaskBufferOwnership); }

template <class UCharPredicate> PassRef<StringImpl> stripMatchedCharacters(UCharPredicate);

template <typename CharType, class UCharPredicate> PassRef<StringImpl> simplifyMatchedCharactersToSpace(UCharPredicate);

template <typename CharType> static PassRef<StringImpl> constructInternal(StringImpl*, unsigned);

template <typename CharType> static PassRef<StringImpl> createUninitializedInternal(unsigned, CharType*&);

template <typename CharType> static PassRef<StringImpl> createUninitializedInternalNonEmpty(unsigned, CharType*&);

template <typename CharType> static PassRef<StringImpl> reallocateInternal(PassRefPtr<StringImpl>, unsigned, CharType*&);

template <typename CharType> static PassRef<StringImpl> createInternal(const CharType*, unsigned);

WTF_EXPORT_PRIVATE NEVER_INLINE unsigned hashSlowCase() const;

WTF_EXPORT_PRIVATE unsigned hashAndFlagsForEmptyUnique();

// The bottom bit in the ref count indicates a static (immortal) string.

static const unsigned s_refCountFlagIsStaticString = 0x1;

static const unsigned s_refCountIncrement = 0x2; // This allows us to ref / deref without disturbing the static string flag.

// The bottom 6 bits in the hash are flags.

static const unsigned s_flagCount = 6;

static const unsigned s_flagMask = (1u << s_flagCount) - 1;

COMPILE_ASSERT(s_flagCount <= StringHasher::flagCount, StringHasher_reserves_enough_bits_for_StringImpl_flags);

static const unsigned s_hashFlag8BitBuffer = 1u << 5;

static const unsigned s_hashFlagIsAtomic = 1u << 4;

static const unsigned s_hashFlagDidReportCost = 1u << 3;

static const unsigned s_hashMaskBufferOwnership = 1u | (1u << 1);

#ifdef STRING_STATS

WTF_EXPORTDATA static StringStats m_stringStats;

#endif

public:

struct StaticASCIILiteral {

// These member variables must match the layout of StringImpl.

unsigned m_refCount;

unsigned m_length;

const LChar* m_data8;

unsigned m_hashAndFlags;

// These values mimic ConstructFromLiteral.

static const unsigned s_initialRefCount = s_refCountIncrement;

static const unsigned s_initialFlags = s_hashFlag8BitBuffer | BufferInternal;

static const unsigned s_hashShift = s_flagCount;

};

#ifndef NDEBUG

void assertHashIsCorrect()

{

ASSERT(hasHash());

ASSERT(existingHash() == StringHasher::computeHashAndMaskTop8Bits(characters8(), length()));

}

#endif

private:

// These member variables must match the layout of StaticASCIILiteral.

unsigned m_refCount;

unsigned m_length;

union {

const LChar* m_data8;

const UChar* m_data16;

};

mutable unsigned m_hashAndFlags;

};

static_assert(sizeof(StringImpl) == sizeof(StringImpl::StaticASCIILiteral), "");

#if !ASSERT_DISABLED

template<> struct

ValueCheck<StringImpl*> {

static void checkConsistency(const StringImpl*) { }

};

#endif

template <>

ALWAYS_INLINE PassRef<StringImpl> StringImpl::constructInternal<LChar>(StringImpl* impl, unsigned length) { return adoptRef(*new (NotNull, impl) StringImpl(length, Force8BitConstructor)); }

template <>

ALWAYS_INLINE PassRef<StringImpl> StringImpl::constructInternal<UChar>(StringImpl* impl, unsigned length) { return adoptRef(*new (NotNull, impl) StringImpl(length)); }

template <>

ALWAYS_INLINE const LChar* StringImpl::characters<LChar>() const { return characters8(); }

template <>

ALWAYS_INLINE const UChar* StringImpl::characters<UChar>() const { return characters16(); }

WTF_EXPORT_STRING_API bool equal(const StringImpl*, const StringImpl*);

WTF_EXPORT_STRING_API bool equal(const StringImpl*, const LChar*);

inline bool equal(const StringImpl* a, const char* b) { return equal(a, reinterpret_cast<const LChar*>(b)); }

WTF_EXPORT_STRING_API bool equal(const StringImpl*, const LChar*, unsigned);

WTF_EXPORT_STRING_API bool equal(const StringImpl*, const UChar*, unsigned);

inline bool equal(const StringImpl* a, const char* b, unsigned length) { return equal(a, reinterpret_cast<const LChar*>(b), length); }

inline bool equal(const LChar* a, StringImpl* b) { return equal(b, a); }

inline bool equal(const char* a, StringImpl* b) { return equal(b, reinterpret_cast<const LChar*>(a)); }

WTF_EXPORT_STRING_API bool equal(const StringImpl& a, const StringImpl& b);

template<typename T>

inline T loadUnaligned(const char* s)

{

#if COMPILER(CLANG)

T tmp;

memcpy(&tmp, s, sizeof(T));

return tmp;

#else

// This may result in undefined behavior due to unaligned access.

return *reinterpret_cast<const T*>(s);

#endif

}

#if CPU(X86_64) || CPU(ARM64)

ALWAYS_INLINE bool equal(const LChar* aLChar, const LChar* bLChar, unsigned length)

{

unsigned dwordLength = length >> 3;

const char* a = reinterpret_cast<const char*>(aLChar);

const char* b = reinterpret_cast<const char*>(bLChar);

if (dwordLength) {

for (unsigned i = 0; i != dwordLength; ++i) {

if (loadUnaligned<uint64_t>(a) != loadUnaligned<uint64_t>(b))

return false;

a += sizeof(uint64_t);

b += sizeof(uint64_t);

}

}

if (length & 4) {

if (loadUnaligned<uint32_t>(a) != loadUnaligned<uint32_t>(b))

return false;

a += sizeof(uint32_t);

b += sizeof(uint32_t);

}

if (length & 2) {

if (loadUnaligned<uint16_t>(a) != loadUnaligned<uint16_t>(b))

return false;

a += sizeof(uint16_t);

b += sizeof(uint16_t);

}

if (length & 1 && (*reinterpret_cast<const LChar*>(a) != *reinterpret_cast<const LChar*>(b)))

return false;

return true;

}

ALWAYS_INLINE bool equal(const UChar* aUChar, const UChar* bUChar, unsigned length)

{

unsigned dwordLength = length >> 2;

const char* a = reinterpret_cast<const char*>(aUChar);

const char* b = reinterpret_cast<const char*>(bUChar);

if (dwordLength) {

for (unsigned i = 0; i != dwordLength; ++i) {

if (loadUnaligned<uint64_t>(a) != loadUnaligned<uint64_t>(b))

return false;

a += sizeof(uint64_t);

b += sizeof(uint64_t);

}

}

if (length & 2) {

if (loadUnaligned<uint32_t>(a) != loadUnaligned<uint32_t>(b))

return false;

a += sizeof(uint32_t);

b += sizeof(uint32_t);

}

if (length & 1 && (*reinterpret_cast<const UChar*>(a) != *reinterpret_cast<const UChar*>(b)))

return false;

return true;

}

#elif CPU(X86)

ALWAYS_INLINE bool equal(const LChar* aLChar, const LChar* bLChar, unsigned length)

{

const char* a = reinterpret_cast<const char*>(aLChar);

const char* b = reinterpret_cast<const char*>(bLChar);

unsigned wordLength = length >> 2;

for (unsigned i = 0; i != wordLength; ++i) {

if (loadUnaligned<uint32_t>(a) != loadUnaligned<uint32_t>(b))

return false;

a += sizeof(uint32_t);

b += sizeof(uint32_t);

}

length &= 3;

if (length) {

const LChar* aRemainder = reinterpret_cast<const LChar*>(a);

const LChar* bRemainder = reinterpret_cast<const LChar*>(b);

for (unsigned i = 0; i < length; ++i) {

if (aRemainder[i] != bRemainder[i])

return false;

}

}

return true;

}

ALWAYS_INLINE bool equal(const UChar* aUChar, const UChar* bUChar, unsigned length)

{

const char* a = reinterpret_cast<const char*>(aUChar);

const char* b = reinterpret_cast<const char*>(bUChar);

unsigned wordLength = length >> 1;

for (unsigned i = 0; i != wordLength; ++i) {

if (loadUnaligned<uint32_t>(a) != loadUnaligned<uint32_t>(b))

return false;

a += sizeof(uint32_t);

b += sizeof(uint32_t);

}

if (length & 1 && *reinterpret_cast<const UChar*>(a) != *reinterpret_cast<const UChar*>(b))

return false;

return true;

}

#elif PLATFORM(IOS) && WTF_ARM_ARCH_AT_LEAST(7)

ALWAYS_INLINE bool equal(const LChar* a, const LChar* b, unsigned length)

{

bool isEqual = false;

uint32_t aValue;

uint32_t bValue;

asm("subs %[length], #4\n"

"blo 2f\n"

"0:\n" // Label 0 = Start of loop over 32 bits.

"ldr %[aValue], [%[a]], #4\n"