JSStringJoiner.cpp [plain text]
#include "config.h"
#include "JSStringJoiner.h"
#include "JSCInlines.h"
namespace JSC {
JSStringJoiner::~JSStringJoiner()
{
}
template<typename CharacterType>
static inline void appendStringToData(CharacterType*& data, StringView string)
{
string.getCharactersWithUpconvert(data);
data += string.length();
}
template<typename CharacterType>
static inline String joinStrings(const Vector<StringViewWithUnderlyingString>& strings, StringView separator, unsigned joinedLength)
{
ASSERT(joinedLength);
CharacterType* data;
String result = StringImpl::tryCreateUninitialized(joinedLength, data);
if (UNLIKELY(result.isNull()))
return result;
appendStringToData(data, strings[0].view);
unsigned size = strings.size();
switch (separator.length()) {
case 0:
for (unsigned i = 1; i < size; ++i)
appendStringToData(data, strings[i].view);
break;
case 1: {
CharacterType separatorCharacter = separator[0];
for (unsigned i = 1; i < size; ++i) {
*data++ = separatorCharacter;
appendStringToData(data, strings[i].view);
}
break;
}
default:
for (unsigned i = 1; i < size; ++i) {
appendStringToData(data, separator);
appendStringToData(data, strings[i].view);
}
}
ASSERT(data == result.characters<CharacterType>() + joinedLength);
return result;
}
inline unsigned JSStringJoiner::joinedLength(ExecState& state) const
{
VM& vm = state.vm();
auto scope = DECLARE_THROW_SCOPE(vm);
unsigned numberOfStrings = m_strings.size();
if (!numberOfStrings)
return 0;
Checked<int32_t, RecordOverflow> separatorLength = m_separator.length();
Checked<int32_t, RecordOverflow> totalSeparatorsLength = separatorLength * (numberOfStrings - 1);
Checked<int32_t, RecordOverflow> totalLength = totalSeparatorsLength + m_accumulatedStringsLength;
int32_t result;
if (totalLength.safeGet(result) == CheckedState::DidOverflow) {
throwOutOfMemoryError(&state, scope);
return 0;
}
return result;
}
JSValue JSStringJoiner::join(ExecState& state)
{
VM& vm = state.vm();
auto scope = DECLARE_THROW_SCOPE(vm);
ASSERT(m_strings.size() <= m_strings.capacity());
unsigned length = joinedLength(state);
RETURN_IF_EXCEPTION(scope, JSValue());
if (!length)
return jsEmptyString(&state);
String result;
if (m_isAll8Bit)
result = joinStrings<LChar>(m_strings, m_separator, length);
else
result = joinStrings<UChar>(m_strings, m_separator, length);
if (result.isNull())
return throwOutOfMemoryError(&state, scope);
return jsString(&state, WTFMove(result));
}
}