TokenBucket.cpp

/*
** libutil++
** $Id: TokenBucket.cpp 1653 2016-02-28 19:54:59Z sella $
** Copyright (c) 2011-2016 Digital Genesis, LLC. All Rights Reserved.
** Released under the LGPL Version 2.1 License.
** http://www.digitalgenesis.com
*/

static const char rcsid[] __attribute__((used)) = "$Id: TokenBucket.cpp 1653 2016-02-28 19:54:59Z sella $";

#include "TokenBucket.h"

#include <sys/time.h>
#include <stdlib.h>
#include <unistd.h>

using namespace sella::algo;

TokenBucket::TokenBucket(const TokenBucket & chain, double limit) throw () :
        chain(std::make_shared<TokenBucket>(chain)),

        stamp(0),

        limit(limit),
        value(0.0)
{ }

TokenBucket::TokenBucket(double limit) throw () :
        chain(),

        stamp(0),

        limit(limit),
        value(0.0)
{ }

bool TokenBucket::sub(double value, bool blocking) throw () {
        struct timeval  stamp;
        uint64_t        usecs;

retry:
        if (this->chain.get() != NULL) {
                if (this->chain->sub(value, blocking) == false) {
                        return false;
                }
        }

        gettimeofday(&stamp, NULL);
        usecs = (stamp.tv_sec * 1000000) + stamp.tv_usec;

        if ((this->value += ((usecs - this->stamp) * this->limit) / 1000000) > this->limit) {
                this->value = this->limit;
        }
        this->stamp = usecs;

        if (this->value > 0.0) {
                this->value -= value;

                return true;
        }

        if (this->chain.get() != NULL) {
                this->chain->add(value);
        }

        if (blocking) {
                usleep((0.0 - value) / this->limit * 1000000);
                goto retry;
        }
        return false;
}

bool TokenBucket::add(double value) throw () {
        if ((this->value += value) > this->limit) {
                this->value = this->limit;
        }
        return true;
}

/*
** vim: noet ts=3 sw=3
*/