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sems/core/AmStats.h

136 lines
2.8 KiB

/*
* Copyright (C) 2002-2003 Fhg Fokus
*
* This file is part of SEMS, a free SIP media server.
*
* SEMS is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version. This program is released under
* the GPL with the additional exemption that compiling, linking,
* and/or using OpenSSL is allowed.
*
* For a license to use the SEMS software under conditions
* other than those described here, or to purchase support for this
* software, please contact iptel.org by e-mail at the following addresses:
* info@iptel.org
*
* SEMS 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 this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/** @file AmStats.h */
#ifndef _AmStats_h_
#define _AmStats_h_
#include <sys/types.h>
#include <math.h>
#include <string.h>
/**
* \brief math mean implementation
*
* The mean of all previously stored values is calculated (no reset).
*/
class MeanValue
{
protected:
double cum_val;
size_t n_val;
public:
MeanValue()
: cum_val(0.0),
n_val(0)
{}
virtual ~MeanValue() { }
void push(double val){
cum_val += val;
n_val++;
}
double mean(){
if(!n_val) return 0.0;
return cum_val / float(n_val);
}
};
/**
* \brief math stddev implementation
*
* The standard deviation of previously stored
* values is calculated.
*/
class StddevValue
{
protected:
double cum_val;
double sq_cum_val;
size_t n_val;
public:
StddevValue()
: cum_val(0.0),
sq_cum_val(0.0),
n_val(0)
{}
void push(double val){
cum_val += val;
sq_cum_val += val*val;
n_val++;
}
double stddev(){
if(!n_val) return 0.0;
return sqrt((n_val*sq_cum_val - cum_val*cum_val)/(n_val*(n_val-1)));
}
};
/**
* \brief math mean implementation (n values)
*
* The mean of n previously stored values is calculated
*/
class MeanArray: public MeanValue
{
double *buffer;
size_t buf_size;
public:
MeanArray(size_t size)
: buf_size(size),
MeanValue()
{
buffer = new double[size];
memset(buffer, 0, sizeof(buffer[0])*size);
}
~MeanArray(){
delete [] buffer;
}
void push(double val){
cum_val -= buffer[n_val % buf_size];
buffer[n_val % buf_size] = val;
cum_val += val;
n_val++;
}
double mean(){
if(!n_val) return 0.0;
return cum_val / double(n_val > buf_size ? buf_size : n_val);
}
};
#endif