JSStringJoiner.cpp [plain text]
#include "config.h"
#include "JSStringJoiner.h"
#include "ExceptionHelpers.h"
#include "JSScope.h"
#include "JSString.h"
#include "JSCInlines.h"
#include <wtf/text/StringImpl.h>
namespace JSC {
static inline void appendStringToData(UChar*& data, const String& string)
{
if (string.isNull())
return;
unsigned length = string.length();
const StringImpl* stringImpl = string.impl();
if (stringImpl->is8Bit()) {
for (unsigned i = 0; i < length; ++i) {
*data = stringImpl->characters8()[i];
++data;
}
} else {
for (unsigned i = 0; i < length; ++i) {
*data = stringImpl->characters16()[i];
++data;
}
}
}
static inline void appendStringToData(LChar*& data, const String& string)
{
if (string.isNull())
return;
ASSERT(string.is8Bit());
unsigned length = string.length();
const StringImpl* stringImpl = string.impl();
for (unsigned i = 0; i < length; ++i) {
*data = stringImpl->characters8()[i];
++data;
}
}
template<typename CharacterType>
static inline PassRefPtr<StringImpl> joinStrings(const Vector<String>& strings, const String& separator, unsigned outputLength)
{
ASSERT(outputLength);
CharacterType* data;
RefPtr<StringImpl> outputStringImpl = StringImpl::tryCreateUninitialized(outputLength, data);
if (!outputStringImpl)
return nullptr;
const String firstString = strings.first();
appendStringToData(data, firstString);
for (size_t i = 1; i < strings.size(); ++i) {
appendStringToData(data, separator);
appendStringToData(data, strings[i]);
}
ASSERT(data == (outputStringImpl->characters<CharacterType>() + outputStringImpl->length()));
return outputStringImpl.release();
}
JSValue JSStringJoiner::join(ExecState* exec)
{
if (!m_isValid)
return throwOutOfMemoryError(exec);
if (!m_strings.size())
return jsEmptyString(exec);
Checked<unsigned, RecordOverflow> separatorLength = m_separator.length();
ASSERT(m_strings.size() > 0);
Checked<unsigned, RecordOverflow> totalSeparactorsLength = separatorLength * (m_strings.size() - 1);
Checked<unsigned, RecordOverflow> outputStringSize = totalSeparactorsLength + m_accumulatedStringsLength;
unsigned finalSize;
if (outputStringSize.safeGet(finalSize) == CheckedState::DidOverflow)
return throwOutOfMemoryError(exec);
if (!outputStringSize)
return jsEmptyString(exec);
RefPtr<StringImpl> outputStringImpl;
if (m_is8Bits)
outputStringImpl = joinStrings<LChar>(m_strings, m_separator, finalSize);
else
outputStringImpl = joinStrings<UChar>(m_strings, m_separator, finalSize);
if (!outputStringImpl)
return throwOutOfMemoryError(exec);
return JSString::create(exec->vm(), outputStringImpl.release());
}
}