public:

class Value {

public:

explicit Value(uint32_t raw) : value_(raw) {}

Value() : value_(0) {}

static uint32_t Encode(uint32_t index, bool is_from_api) {

return Index::encode(index) | IsFromAPI::encode(is_from_api);

}

bool is_from_api() const { return IsFromAPI::decode(value_); }

uint32_t index() const { return Index::decode(value_); }

private:

using Index = base::BitField<uint32_t, 0, 31>;

using IsFromAPI = base::BitField<bool, 31, 1>;

uint32_t value_;

};

explicit ExternalReferenceEncoder(Isolate* isolate);

ExternalReferenceEncoder(const ExternalReferenceEncoder&) = delete;

ExternalReferenceEncoder& operator=(const ExternalReferenceEncoder&) = delete;

#ifdef DEBUG

~ExternalReferenceEncoder();

#endif // DEBUG

Value Encode(Address key);

Maybe<Value> TryEncode(Address key);

const char* NameOfAddress(Isolate* isolate, Address address) const;

private:

AddressToIndexHashMap* map_;

#ifdef DEBUG

std::vector<int> count_;

const intptr_t* api_references_;

#endif // DEBUG