Files
falco/userspace/engine/token_bucket.cpp
Mark Stemm c066be3905 Allow the initial time to be externally provided.
Allow the initial start time to be externally provided. Saves a call to
getttimeofday and allows running from an external clock (i.e. trace files).
2017-04-27 12:02:21 -07:00

87 lines
1.6 KiB
C++

/*
Copyright (C) 2016 Draios inc.
This file is part of falco.
falco is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License version 2 as
published by the Free Software Foundation.
falco is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with falco. If not, see <http://www.gnu.org/licenses/>.
*/
#include <cstddef>
#include <sys/time.h>
#include "utils.h"
#include "token_bucket.h"
token_bucket::token_bucket()
{
init(1, 1);
}
token_bucket::~token_bucket()
{
}
void token_bucket::init(double rate, double max_tokens, uint64_t now)
{
m_rate = rate;
m_max_tokens = max_tokens;
m_tokens = max_tokens;
if(now == 0)
{
now = sinsp_utils::get_current_time_ns();
}
m_last_seen = now;
}
bool token_bucket::claim(uint64_t now)
{
// Determine the number of tokens gained. Delta between
// last_seen and now, divided by the rate.
if(now == 0)
{
now = sinsp_utils::get_current_time_ns();
}
double tokens_gained = m_rate * ((now - m_last_seen) / (1000000000.0));
m_last_seen = now;
m_tokens += tokens_gained;
//
// Cap at max_tokens
//
if(m_tokens > m_max_tokens)
{
m_tokens = m_max_tokens;
}
//
// If tokens is < 1, can't claim.
//
if(m_tokens < 1)
{
return false;
}
m_tokens--;
return true;
}
double token_bucket::get_tokens()
{
return m_tokens;
}