wrapping_integers.hh File Reference

#include <cstdint>
#include <ostream>

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Classes
class	WrappingInt32
	A 32-bit integer, expressed relative to an arbitrary initial sequence number (ISN) More...

Functions
uint64_t	unwrap (WrappingInt32 n, WrappingInt32 isn, uint64_t checkpoint)
WrappingInt32	wrap (uint64_t n, WrappingInt32 isn)
Helper functions
bool	operator!= (WrappingInt32 a, WrappingInt32 b)
	Whether the two integers are not equal. More...
WrappingInt32	operator+ (WrappingInt32 a, uint32_t b)
	The point b steps past a. More...
WrappingInt32	operator- (WrappingInt32 a, uint32_t b)
	The point b steps before a. More...
int32_t	operator- (WrappingInt32 a, WrappingInt32 b)
	The offset of a relative to b More...
std::ostream &	operator<< (std::ostream &os, WrappingInt32 a)
	Serializes the wrapping integer, a. More...
bool	operator== (WrappingInt32 a, WrappingInt32 b)
	Whether the two integers are equal. More...

Function Documentation

operator!=()

bool operator!= ( WrappingInt32  a, WrappingInt32  b  )

inline

Whether the two integers are not equal.

Definition at line 53 of file wrapping_integers.hh.

operator+()

WrappingInt32 operator+ ( WrappingInt32  a, uint32_t  b  )

inline

The point b steps past a.

Definition at line 59 of file wrapping_integers.hh.

operator-() [1/2]

WrappingInt32 operator- ( WrappingInt32  a, uint32_t  b  )

inline

The point b steps before a.

Definition at line 62 of file wrapping_integers.hh.

operator-() [2/2]

int32_t operator- ( WrappingInt32  a, WrappingInt32  b  )

inline

The offset of a relative to b

Parameters

b	the starting point
a	the ending point

Returns

the number of increments needed to get from b to a, negative if the number of decrements needed is less than or equal to the number of increments

Definition at line 47 of file wrapping_integers.hh.

operator<<()

std::ostream& operator<< ( std::ostream &  os, WrappingInt32  a  )

inline

Serializes the wrapping integer, a.

Definition at line 56 of file wrapping_integers.hh.

operator==()

bool operator== ( WrappingInt32  a, WrappingInt32  b  )

inline

Whether the two integers are equal.

Definition at line 50 of file wrapping_integers.hh.

unwrap()

uint64_t unwrap	(	WrappingInt32	n,
		WrappingInt32	isn,
		uint64_t	checkpoint
	)

Transform a 32-bit relative sequence number into a 64-bit absolute sequence number (zero-indexed)

Parameters

n	The relative sequence number
isn	The initial sequence number
checkpoint	A recent absolute sequence number

Returns

the absolute sequence number that wraps to n and is closest to checkpoint

Note

Each of the two streams of the TCP connection has its own ISN. One stream runs from the local TCPSender to the remote TCPReceiver and has one ISN, and the other stream runs from the remote TCPSender to the local TCPReceiver and has a different ISN.

wrap()

WrappingInt32 wrap	(	uint64_t	n,
		WrappingInt32	isn
	)

Transform a 64-bit absolute sequence number (zero-indexed) into a 32-bit relative sequence number

Parameters

n	the absolute sequence number
isn	the initial sequence number

Returns

the relative sequence number