#include "config.h"
#include "SmallStrings.h"
#include "JSGlobalObject.h"
#include "JSString.h"
#include <wtf/Noncopyable.h>
namespace JSC {
static const unsigned numCharactersToStore = 0x100;
class SmallStringsStorage : Noncopyable {
public:
SmallStringsStorage();
UString::Rep* rep(unsigned char character) { return &m_reps[character]; }
private:
UChar m_characters[numCharactersToStore];
UString::BaseString m_base;
UString::Rep m_reps[numCharactersToStore];
};
SmallStringsStorage::SmallStringsStorage()
: m_base(m_characters, numCharactersToStore)
{
m_base.rc = numCharactersToStore + 1;
m_base.usedCapacity = numCharactersToStore + 1;
m_base.capacity = numCharactersToStore + 1;
m_base.checkConsistency();
for (unsigned i = 0; i < numCharactersToStore; ++i)
m_characters[i] = i;
memset(&m_reps, 0, sizeof(m_reps));
for (unsigned i = 0; i < numCharactersToStore; ++i) {
m_reps[i].offset = i;
m_reps[i].len = 1;
m_reps[i].rc = 1;
m_reps[i].setBaseString(&m_base);
m_reps[i].checkConsistency();
}
}
SmallStrings::SmallStrings()
: m_emptyString(0)
, m_storage(0)
{
COMPILE_ASSERT(numCharactersToStore == sizeof(m_singleCharacterStrings) / sizeof(m_singleCharacterStrings[0]), IsNumCharactersConstInSyncWithClassUsage);
for (unsigned i = 0; i < numCharactersToStore; ++i)
m_singleCharacterStrings[i] = 0;
}
SmallStrings::~SmallStrings()
{
}
void SmallStrings::mark()
{
if (m_emptyString && !m_emptyString->marked())
m_emptyString->mark();
for (unsigned i = 0; i < numCharactersToStore; ++i) {
if (m_singleCharacterStrings[i] && !m_singleCharacterStrings[i]->marked())
m_singleCharacterStrings[i]->mark();
}
}
unsigned SmallStrings::count() const
{
unsigned count = 0;
if (m_emptyString)
++count;
for (unsigned i = 0; i < numCharactersToStore; ++i) {
if (m_singleCharacterStrings[i])
++count;
}
return count;
}
void SmallStrings::createEmptyString(JSGlobalData* globalData)
{
ASSERT(!m_emptyString);
m_emptyString = new (globalData) JSString(globalData, "", JSString::HasOtherOwner);
}
void SmallStrings::createSingleCharacterString(JSGlobalData* globalData, unsigned char character)
{
if (!m_storage)
m_storage.set(new SmallStringsStorage);
ASSERT(!m_singleCharacterStrings[character]);
m_singleCharacterStrings[character] = new (globalData) JSString(globalData, m_storage->rep(character), JSString::HasOtherOwner);
}
UString::Rep* SmallStrings::singleCharacterStringRep(unsigned char character)
{
if (!m_storage)
m_storage.set(new SmallStringsStorage);
return m_storage->rep(character);
}
}