util::TokenBucket< Clock > Class Template Reference

A token bucket rate limiter. More...

#include <tokenbucket.h>

Public Types
using	clock = Clock
using	time_point = typename Clock::time_point
using	duration = typename Clock::duration

Public Member Functions
	TokenBucket (double rate, double value, double cap)
void	increment (const time_point &now)
	Refill tokens based on elapsed time since last call. More...
bool	decrement (double n=1.0, double floor=0.0)
	Consume n tokens. More...
double	value () const
	Current token balance. More...

Public Attributes
const double	m_rate {1}
	Tokens added per second. More...
const double	m_cap {0}
	Maximum token balance. More...

Private Attributes
time_point	m_last_updated {MIN_TIME}
double	m_value {0}

Static Private Attributes
static constexpr time_point	MIN_TIME {time_point::min()}

Detailed Description

template<typename Clock>
class util::TokenBucket< Clock >

A token bucket rate limiter.

Tokens are added at a steady rate (m_rate per second) up to a capacity cap (m_cap). Tokens are removed by calling decrement(), which returns false if the bucket is emptied.

Typical usage: bucket.increment(now); // refill based on elapsed time if (bucket.value() >= 1) bucket.decrement(1); // consume a token

Definition at line 23 of file tokenbucket.h.

Member Typedef Documentation

clock

template<typename Clock >

using util::TokenBucket< Clock >::clock = Clock

Definition at line 26 of file tokenbucket.h.

duration

template<typename Clock >

using util::TokenBucket< Clock >::duration = typename Clock::duration

Definition at line 28 of file tokenbucket.h.

time_point

template<typename Clock >

using util::TokenBucket< Clock >::time_point = typename Clock::time_point

Definition at line 27 of file tokenbucket.h.

Constructor & Destructor Documentation

TokenBucket()

template<typename Clock >

util::TokenBucket< Clock >::TokenBucket ( double  rate, double  value, double  cap  )

inline

Parameters

rate	Tokens added per second.
value	Initial token balance (clamped to cap).
cap	Maximum token balance.

Definition at line 36 of file tokenbucket.h.

Member Function Documentation

decrement()

template<typename Clock >

bool util::TokenBucket< Clock >::decrement ( double  n = 1.0, double  floor = 0.0  )

inline

Consume n tokens.

Returns false if the balance dropped to/below the given floor.

Definition at line 52 of file tokenbucket.h.

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increment()

template<typename Clock >

void util::TokenBucket< Clock >::increment ( const time_point &  now )

inline

Refill tokens based on elapsed time since last call.

No refill occurs on the first call (establishes the time baseline).

Definition at line 40 of file tokenbucket.h.

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value()

template<typename Clock >

double util::TokenBucket< Clock >::value ( ) const

inline

Current token balance.

Definition at line 59 of file tokenbucket.h.

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Member Data Documentation

m_cap

template<typename Clock >

const double util::TokenBucket< Clock >::m_cap {0}

Maximum token balance.

Definition at line 31 of file tokenbucket.h.

m_last_updated

template<typename Clock >

time_point util::TokenBucket< Clock >::m_last_updated {MIN_TIME}

private

Definition at line 63 of file tokenbucket.h.

m_rate

template<typename Clock >

const double util::TokenBucket< Clock >::m_rate {1}

Tokens added per second.

Definition at line 30 of file tokenbucket.h.

m_value

template<typename Clock >

double util::TokenBucket< Clock >::m_value {0}

private

Definition at line 64 of file tokenbucket.h.

MIN_TIME

template<typename Clock >

constexpr time_point util::TokenBucket< Clock >::MIN_TIME {time_point::min()}

staticconstexprprivate

Definition at line 62 of file tokenbucket.h.

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The documentation for this class was generated from the following file:

• src/util/tokenbucket.h