Provides a C++ rate limit algorithm.

supported algorithms:

• token-bucket
• []

include header

#include "token_bucket.h"

static std::shared_ptr<RateLimiter> NewBucket(std::chrono::nanoseconds fillInterval, int64_t quantum, int64_t capacity);

• fillInterval : interval between each tick
• quantum : the number of tokens are added to bucket
• capacity : the capacity of the bucket

static std::shared_ptr<RateLimiter> NewBucketWithRate(double rate, int64_t capacity);

• rate : the number of tokens are added to bucket per second
• capacity : the capacity of the bucket

std::chrono::nanoseconds Take(int64_t count)

get count tokens from bucket without blocking.

parameters

• count : the number of tokens

return

• duration that the caller should wait

int64_t TakeAvailable(int64_t count)

get min(count, available) tokens from the bucket.

parameters

• count : the number of tokens

return

• int64_t : the number of tokens obtained

int64_t Available()

returns the number of available tokens

return

• int64_t : the number of available tokens

std::chrono::nanoseconds TakeMaxDuration(int64_t count, std::chrono::nanoseconds maxWait)

get count tokens from bucket, if the wait time returned is no greater than maxWait.

paremeters

• count : the number of tokens wish to obtain
• maxWait : max waiting time

return

• std::chrono::nanoseconds :
  • if the wait time which is returned is greater than maxWait, it does nothing.
  • if the wait time which is returned is not greater than maxWait, the count token becomes available.

void Wait(int64_t count)

wait takes count tokens from the bucket, waiting until they are available.

parameters

• count : the number of tokens

bool WaitMaxDuration(int64_t count, std::chrono::nanoseconds maxWait)

take tokens from the bucket if it needs to wait for no greater than maxWait.

parameters

• count : the number of tokens
• maxWait : max waiting time

return

• bool :
  • if the wait time is greater than maxWait, it does nothing and return false.
  • if the wait time is not greater than maxWait, it takes count tokens until they are available.