#include "config.h"
#include <wtf/text/StringBuilder.h>
#include <wtf/dtoa.h>
namespace WTF {
static constexpr unsigned maxCapacity = String::MaxLength;
static unsigned expandedCapacity(unsigned capacity, unsigned requiredLength)
{
static constexpr unsigned minimumCapacity = 16;
return std::max(requiredLength, std::max(minimumCapacity, std::min(capacity * 2, maxCapacity)));
}
void StringBuilder::reifyString() const
{
ASSERT(!hasOverflowed());
if (!m_string.isNull()) {
ASSERT(m_string.length() == m_length.unsafeGet<unsigned>());
return;
}
#if ASSERT_ENABLED
m_isReified = true;
#endif
if (!m_length) {
m_string = StringImpl::empty();
return;
}
ASSERT(m_buffer && m_length.unsafeGet<unsigned>() <= m_buffer->length());
if (m_length.unsafeGet<unsigned>() == m_buffer->length())
m_string = m_buffer.get();
else
m_string = StringImpl::createSubstringSharingImpl(*m_buffer, 0, m_length.unsafeGet());
}
void StringBuilder::resize(unsigned newSize)
{
if (hasOverflowed())
return;
unsigned oldLength = m_length.unsafeGet();
ASSERT(newSize <= oldLength);
if (newSize == oldLength)
return;
ASSERT(oldLength);
m_length = newSize;
ASSERT(!hasOverflowed());
if (m_buffer) {
m_string = String(); if (!m_buffer->hasOneRef()) {
if (m_buffer->is8Bit())
allocateBuffer(m_buffer->characters8(), m_buffer->length());
else
allocateBuffer(m_buffer->characters16(), m_buffer->length());
}
ASSERT(hasOverflowed() || m_buffer->length() >= m_length.unsafeGet<unsigned>());
return;
}
ASSERT(!m_string.isEmpty());
ASSERT(oldLength == m_string.length());
ASSERT(newSize < m_string.length());
m_string = StringImpl::createSubstringSharingImpl(*m_string.impl(), 0, newSize);
}
void StringBuilder::allocateBuffer(const LChar* currentCharacters, unsigned requiredLength)
{
ASSERT(!hasOverflowed());
ASSERT(m_is8Bit);
auto buffer = StringImpl::tryCreateUninitialized(requiredLength, m_bufferCharacters8);
if (UNLIKELY(!buffer))
return didOverflow();
std::memcpy(m_bufferCharacters8, currentCharacters, m_length.unsafeGet());
m_buffer = WTFMove(buffer);
m_string = String();
ASSERT(m_buffer->length() == requiredLength);
}
void StringBuilder::allocateBuffer(const UChar* currentCharacters, unsigned requiredLength)
{
ASSERT(!hasOverflowed());
ASSERT(!m_is8Bit);
auto buffer = StringImpl::tryCreateUninitialized(requiredLength, m_bufferCharacters16);
if (UNLIKELY(!buffer))
return didOverflow();
std::memcpy(m_bufferCharacters16, currentCharacters, static_cast<size_t>(m_length.unsafeGet()) * sizeof(UChar));
m_buffer = WTFMove(buffer);
m_string = String();
ASSERT(m_buffer->length() == requiredLength);
}
void StringBuilder::allocateBufferUpConvert(const LChar* currentCharacters, unsigned requiredLength)
{
ASSERT(!hasOverflowed());
ASSERT(m_is8Bit);
unsigned length = m_length.unsafeGet();
ASSERT(requiredLength <= maxCapacity && requiredLength >= length);
auto buffer = StringImpl::tryCreateUninitialized(requiredLength, m_bufferCharacters16);
if (UNLIKELY(!buffer))
return didOverflow(); for (unsigned i = 0; i < length; ++i)
m_bufferCharacters16[i] = currentCharacters[i];
m_is8Bit = false;
m_buffer = WTFMove(buffer);
m_string = String();
ASSERT(m_buffer->length() == requiredLength);
}
template<>
void StringBuilder::reallocateBuffer<LChar>(unsigned requiredLength)
{
m_string = String();
ASSERT(m_is8Bit);
ASSERT(m_buffer->is8Bit());
if (m_buffer->hasOneRef()) {
auto expectedStringImpl = StringImpl::tryReallocate(m_buffer.releaseNonNull(), requiredLength, m_bufferCharacters8);
if (UNLIKELY(!expectedStringImpl))
return didOverflow();
m_buffer = WTFMove(expectedStringImpl.value());
} else
allocateBuffer(m_buffer->characters8(), requiredLength);
ASSERT(hasOverflowed() || m_buffer->length() == requiredLength);
}
template<>
void StringBuilder::reallocateBuffer<UChar>(unsigned requiredLength)
{
m_string = String();
if (m_buffer->is8Bit())
allocateBufferUpConvert(m_buffer->characters8(), requiredLength);
else if (m_buffer->hasOneRef()) {
auto expectedStringImpl = StringImpl::tryReallocate(m_buffer.releaseNonNull(), requiredLength, m_bufferCharacters16);
if (UNLIKELY(!expectedStringImpl))
return didOverflow();
m_buffer = WTFMove(expectedStringImpl.value());
} else
allocateBuffer(m_buffer->characters16(), requiredLength);
ASSERT(hasOverflowed() || m_buffer->length() == requiredLength);
}
void StringBuilder::reserveCapacity(unsigned newCapacity)
{
if (hasOverflowed())
return;
ASSERT(newCapacity <= String::MaxLength);
if (m_buffer) {
if (newCapacity > m_buffer->length()) {
if (m_buffer->is8Bit())
reallocateBuffer<LChar>(newCapacity);
else
reallocateBuffer<UChar>(newCapacity);
}
} else {
unsigned length = m_length.unsafeGet();
if (newCapacity > length) {
if (!length) {
LChar* nullPlaceholder = nullptr;
allocateBuffer(nullPlaceholder, newCapacity);
} else if (m_string.is8Bit())
allocateBuffer(m_string.characters8(), newCapacity);
else
allocateBuffer(m_string.characters16(), newCapacity);
}
}
ASSERT(hasOverflowed() || !newCapacity || m_buffer->length() >= newCapacity);
}
template<typename CharacterType> ALWAYS_INLINE CharacterType* StringBuilder::extendBufferForAppending(unsigned additionalLength)
{
ASSERT(additionalLength);
CheckedInt32 requiredLength = m_length + additionalLength;
if (requiredLength.hasOverflowed()) {
didOverflow();
return nullptr;
}
return extendBufferForAppendingWithoutOverflowCheck<CharacterType>(requiredLength);
}
template<typename CharacterType> ALWAYS_INLINE CharacterType* StringBuilder::extendBufferForAppendingWithoutOverflowCheck(CheckedInt32 requiredLength)
{
ASSERT(!requiredLength.hasOverflowed());
if (m_buffer && (requiredLength.unsafeGet<unsigned>() <= m_buffer->length())) {
ASSERT(m_buffer->length() >= m_length.unsafeGet<unsigned>());
unsigned currentLength = m_length.unsafeGet();
m_string = String();
m_length = requiredLength;
return getBufferCharacters<CharacterType>() + currentLength;
}
return extendBufferForAppendingSlowCase<CharacterType>(requiredLength.unsafeGet());
}
LChar* StringBuilder::extendBufferForAppending8(CheckedInt32 requiredLength)
{
if (UNLIKELY(requiredLength.hasOverflowed())) {
didOverflow();
return nullptr;
}
return extendBufferForAppendingWithoutOverflowCheck<LChar>(requiredLength);
}
UChar* StringBuilder::extendBufferForAppending16(CheckedInt32 requiredLength)
{
if (UNLIKELY(requiredLength.hasOverflowed())) {
didOverflow();
return nullptr;
}
if (m_is8Bit) {
const LChar* characters;
if (m_buffer) {
ASSERT(m_buffer->length() >= m_length.unsafeGet<unsigned>());
characters = m_buffer->characters8();
} else {
ASSERT(m_string.length() == m_length.unsafeGet<unsigned>());
characters = m_string.isNull() ? nullptr : m_string.characters8();
}
allocateBufferUpConvert(characters, expandedCapacity(capacity(), requiredLength.unsafeGet()));
if (UNLIKELY(hasOverflowed()))
return nullptr;
unsigned oldLength = m_length.unsafeGet();
m_length = requiredLength.unsafeGet();
return m_bufferCharacters16 + oldLength;
}
return extendBufferForAppendingWithoutOverflowCheck<UChar>(requiredLength);
}
template<typename CharacterType> CharacterType* StringBuilder::extendBufferForAppendingSlowCase(unsigned requiredLength)
{
ASSERT(!hasOverflowed());
ASSERT(requiredLength);
if (m_buffer) {
ASSERT(m_buffer->length() >= m_length.unsafeGet<unsigned>());
reallocateBuffer<CharacterType>(expandedCapacity(capacity(), requiredLength));
} else {
ASSERT(m_string.length() == m_length.unsafeGet<unsigned>());
allocateBuffer(m_length ? m_string.characters<CharacterType>() : nullptr, expandedCapacity(capacity(), requiredLength));
}
if (UNLIKELY(hasOverflowed()))
return nullptr;
CharacterType* result = getBufferCharacters<CharacterType>() + m_length.unsafeGet();
m_length = requiredLength;
ASSERT(!hasOverflowed());
ASSERT(m_buffer->length() >= m_length.unsafeGet<unsigned>());
return result;
}
void StringBuilder::appendCharacters(const UChar* characters, unsigned length)
{
if (!length || hasOverflowed())
return;
ASSERT(characters);
if (m_is8Bit && length == 1 && isLatin1(characters[0])) {
append(static_cast<LChar>(characters[0]));
return;
}
UChar* destination = extendBufferForAppending16(m_length + length);
if (UNLIKELY(!destination))
return;
std::memcpy(destination, characters, static_cast<size_t>(length) * sizeof(UChar));
ASSERT(!hasOverflowed());
ASSERT(m_buffer->length() >= m_length.unsafeGet<unsigned>());
}
void StringBuilder::appendCharacters(const LChar* characters, unsigned length)
{
if (!length || hasOverflowed())
return;
ASSERT(characters);
if (m_is8Bit) {
LChar* destination = extendBufferForAppending<LChar>(length);
if (!destination) {
ASSERT(hasOverflowed());
return;
}
if (length > 8)
std::memcpy(destination, characters, length);
else {
const LChar* end = characters + length;
while (characters < end)
*destination++ = *characters++;
}
} else {
UChar* destination = extendBufferForAppending<UChar>(length);
if (!destination) {
ASSERT(hasOverflowed());
return;
}
const LChar* end = characters + length;
while (characters < end)
*destination++ = *characters++;
}
}
#if USE(CF)
void StringBuilder::append(CFStringRef string)
{
if (auto* characters = CFStringGetCStringPtr(string, kCFStringEncodingISOLatin1)) {
appendCharacters(reinterpret_cast<const LChar*>(characters), CFStringGetLength(string));
return;
}
append(String(string));
}
#endif
void StringBuilder::appendNumber(int number)
{
numberToStringSigned<StringBuilder>(number, this);
}
void StringBuilder::appendNumber(unsigned number)
{
numberToStringUnsigned<StringBuilder>(number, this);
}
void StringBuilder::appendNumber(long number)
{
numberToStringSigned<StringBuilder>(number, this);
}
void StringBuilder::appendNumber(unsigned long number)
{
numberToStringUnsigned<StringBuilder>(number, this);
}
void StringBuilder::appendNumber(long long number)
{
numberToStringSigned<StringBuilder>(number, this);
}
void StringBuilder::appendNumber(unsigned long long number)
{
numberToStringUnsigned<StringBuilder>(number, this);
}
void StringBuilder::appendNumber(float number)
{
NumberToStringBuffer buffer;
append(numberToString(number, buffer));
}
void StringBuilder::appendNumber(double number)
{
NumberToStringBuffer buffer;
append(numberToString(number, buffer));
}
bool StringBuilder::canShrink() const
{
if (hasOverflowed())
return false;
unsigned length = m_length.unsafeGet();
return m_buffer && m_buffer->length() > (length + (length >> 2));
}
void StringBuilder::shrinkToFit()
{
if (canShrink()) {
if (m_is8Bit)
reallocateBuffer<LChar>(m_length.unsafeGet());
else
reallocateBuffer<UChar>(m_length.unsafeGet());
ASSERT(!hasOverflowed());
m_string = WTFMove(m_buffer);
}
}
bool StringBuilder::isAllASCII() const
{
auto length = this->length();
if (!length)
return true;
if (m_is8Bit)
return charactersAreAllASCII(characters8(), length);
return charactersAreAllASCII(characters16(), length);
}
}