public:

static constexpr size_t kMinLength = NGTCP2_MIN_CIDLEN;

static constexpr size_t kMaxLength = NGTCP2_MAX_CIDLEN;

// Copy the given ngtcp2_cid.

explicit CID(const ngtcp2_cid& cid);

// Copy the given buffer as a CID. The len must be within

// kMinLength and kMaxLength.

explicit CID(const uint8_t* data, size_t len);

// Wrap the given ngtcp2_cid. The CID does not take ownership

// of the underlying ngtcp2_cid.

explicit CID(const ngtcp2_cid* cid);

CID(const CID& other);

CID& operator=(const CID& other);

CID(CID&&) = delete;

struct Hash final {

size_t operator()(const CID& cid) const;

};

bool operator==(const CID& other) const noexcept;

bool operator!=(const CID& other) const noexcept;

operator const uint8_t*() const;

operator const ngtcp2_cid&() const;

operator const ngtcp2_cid*() const;

// True if the CID length is at least kMinLength;

operator bool() const;

size_t length() const;

std::string ToString() const;

SET_NO_MEMORY_INFO()

SET_MEMORY_INFO_NAME(CID)

SET_SELF_SIZE(CID)

template <typename T>

using Map = std::unordered_map<CID, T, CID::Hash>;

// A CID::Factory, as the name suggests, is used to create new CIDs.

// Per https://datatracker.ietf.org/doc/draft-ietf-quic-load-balancers/, QUIC

// implementations MAY use the Connection ID associated with a QUIC session

// as a routing mechanism, with each CID instance securely encoding the

// routing information. By default, our implementation creates CIDs randomly

// but will allow user code to provide their own CID::Factory implementation.

class Factory;

static CID kInvalid;

// The default constructor creates an empty, zero-length CID.

// Zero-length CIDs are not usable. We use them as a placeholder

// for a missing or empty CID value. This is public only because

// it is required for the CID::Map implementation. It should not

// be used. Use kInvalid instead.

CID();

private:

ngtcp2_cid cid_;

const ngtcp2_cid* ptr_;

friend struct Hash;