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// Copyright (c) 2019 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef QUICHE_QUIC_CORE_QUIC_PACKET_NUMBER_H_
#define QUICHE_QUIC_CORE_QUIC_PACKET_NUMBER_H_
#include <limits>
#include <ostream>
#include <string>
#include "quiche/quic/platform/api/quic_export.h"
#include "quiche/quic/platform/api/quic_logging.h"
namespace quic {
// QuicPacketNumber can either initialized or uninitialized. An initialized
// packet number is simply an ordinal number. A sentinel value is used to
// represent an uninitialized packet number.
class QUIC_EXPORT_PRIVATE QuicPacketNumber {
public:
// Construct an uninitialized packet number.
constexpr QuicPacketNumber() : packet_number_(UninitializedPacketNumber()) {}
// Construct a packet number from uint64_t. |packet_number| cannot equal the
// sentinel value.
explicit constexpr QuicPacketNumber(uint64_t packet_number)
: packet_number_(packet_number) {
QUICHE_DCHECK_NE(UninitializedPacketNumber(), packet_number)
<< "Use default constructor for uninitialized packet number";
}
// The sentinel value representing an uninitialized packet number.
static constexpr uint64_t UninitializedPacketNumber() {
return std::numeric_limits<uint64_t>::max();
}
// Packet number becomes uninitialized after calling this function.
void Clear();
// Updates this packet number to be |new_value| if it is greater than current
// value.
void UpdateMax(QuicPacketNumber new_value);
// REQUIRES: IsInitialized() == true.
uint64_t Hash() const;
// Converts packet number to uint64_t.
// REQUIRES: IsInitialized() == true.
uint64_t ToUint64() const;
// Returns true if packet number is considered initialized.
bool IsInitialized() const;
// REQUIRES: IsInitialized() == true && ToUint64() <
// numeric_limits<uint64_t>::max() - 1.
QuicPacketNumber& operator++();
QuicPacketNumber operator++(int);
// REQUIRES: IsInitialized() == true && ToUint64() >= 1.
QuicPacketNumber& operator--();
QuicPacketNumber operator--(int);
// REQUIRES: IsInitialized() == true && numeric_limits<uint64_t>::max() -
// ToUint64() > |delta|.
QuicPacketNumber& operator+=(uint64_t delta);
// REQUIRES: IsInitialized() == true && ToUint64() >= |delta|.
QuicPacketNumber& operator-=(uint64_t delta);
// Human-readable representation suitable for logging.
std::string ToString() const;
QUIC_EXPORT_PRIVATE friend std::ostream& operator<<(
std::ostream& os, const QuicPacketNumber& p);
private:
// All following operators REQUIRE operands.Initialized() == true.
friend inline bool operator==(QuicPacketNumber lhs, QuicPacketNumber rhs);
friend inline bool operator!=(QuicPacketNumber lhs, QuicPacketNumber rhs);
friend inline bool operator<(QuicPacketNumber lhs, QuicPacketNumber rhs);
friend inline bool operator<=(QuicPacketNumber lhs, QuicPacketNumber rhs);
friend inline bool operator>(QuicPacketNumber lhs, QuicPacketNumber rhs);
friend inline bool operator>=(QuicPacketNumber lhs, QuicPacketNumber rhs);
// REQUIRES: numeric_limits<uint64_t>::max() - lhs.ToUint64() > |delta|.
friend inline QuicPacketNumber operator+(QuicPacketNumber lhs,
uint64_t delta);
// REQUIRES: lhs.ToUint64() >= |delta|.
friend inline QuicPacketNumber operator-(QuicPacketNumber lhs,
uint64_t delta);
// REQUIRES: lhs >= rhs.
friend inline uint64_t operator-(QuicPacketNumber lhs, QuicPacketNumber rhs);
uint64_t packet_number_;
};
class QUIC_EXPORT_PRIVATE QuicPacketNumberHash {
public:
uint64_t operator()(QuicPacketNumber packet_number) const noexcept {
return packet_number.Hash();
}
};
inline bool operator==(QuicPacketNumber lhs, QuicPacketNumber rhs) {
QUICHE_DCHECK(lhs.IsInitialized() && rhs.IsInitialized())
<< lhs << " vs. " << rhs;
return lhs.packet_number_ == rhs.packet_number_;
}
inline bool operator!=(QuicPacketNumber lhs, QuicPacketNumber rhs) {
QUICHE_DCHECK(lhs.IsInitialized() && rhs.IsInitialized())
<< lhs << " vs. " << rhs;
return lhs.packet_number_ != rhs.packet_number_;
}
inline bool operator<(QuicPacketNumber lhs, QuicPacketNumber rhs) {
QUICHE_DCHECK(lhs.IsInitialized() && rhs.IsInitialized())
<< lhs << " vs. " << rhs;
return lhs.packet_number_ < rhs.packet_number_;
}
inline bool operator<=(QuicPacketNumber lhs, QuicPacketNumber rhs) {
QUICHE_DCHECK(lhs.IsInitialized() && rhs.IsInitialized())
<< lhs << " vs. " << rhs;
return lhs.packet_number_ <= rhs.packet_number_;
}
inline bool operator>(QuicPacketNumber lhs, QuicPacketNumber rhs) {
QUICHE_DCHECK(lhs.IsInitialized() && rhs.IsInitialized())
<< lhs << " vs. " << rhs;
return lhs.packet_number_ > rhs.packet_number_;
}
inline bool operator>=(QuicPacketNumber lhs, QuicPacketNumber rhs) {
QUICHE_DCHECK(lhs.IsInitialized() && rhs.IsInitialized())
<< lhs << " vs. " << rhs;
return lhs.packet_number_ >= rhs.packet_number_;
}
inline QuicPacketNumber operator+(QuicPacketNumber lhs, uint64_t delta) {
#ifndef NDEBUG
QUICHE_DCHECK(lhs.IsInitialized());
QUICHE_DCHECK_GT(std::numeric_limits<uint64_t>::max() - lhs.ToUint64(),
delta);
#endif
return QuicPacketNumber(lhs.packet_number_ + delta);
}
inline QuicPacketNumber operator-(QuicPacketNumber lhs, uint64_t delta) {
#ifndef NDEBUG
QUICHE_DCHECK(lhs.IsInitialized());
QUICHE_DCHECK_GE(lhs.ToUint64(), delta);
#endif
return QuicPacketNumber(lhs.packet_number_ - delta);
}
inline uint64_t operator-(QuicPacketNumber lhs, QuicPacketNumber rhs) {
QUICHE_DCHECK(lhs.IsInitialized() && rhs.IsInitialized() && lhs >= rhs)
<< lhs << " vs. " << rhs;
return lhs.packet_number_ - rhs.packet_number_;
}
} // namespace quic
#endif // QUICHE_QUIC_CORE_QUIC_PACKET_NUMBER_H_
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