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transmission/libtransmission/ratecontrol.c

156 lines
3.6 KiB
C

/******************************************************************************
* $Id$
*
* Copyright (c) 2006-2008 Transmission authors and contributors
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*****************************************************************************/
#include <string.h> /* memset */
#include "transmission.h"
#include "platform.h"
#include "ratecontrol.h"
#include "utils.h"
#define GRANULARITY_MSEC 500
#define SHORT_INTERVAL_MSEC 4000
#define LONG_INTERVAL_MSEC 8000
#define HISTORY_SIZE (LONG_INTERVAL_MSEC / GRANULARITY_MSEC)
struct tr_transfer
{
uint64_t date;
uint64_t size;
};
struct tr_ratecontrol
{
int limit;
int newest;
struct tr_transfer transfers[HISTORY_SIZE];
};
/* return the xfer rate over the last `interval' seconds in KiB/sec */
static float
rateForInterval( const tr_ratecontrol * r, int interval_msec )
{
uint64_t bytes = 0;
const uint64_t cutoff = tr_date () - interval_msec;
int i = r->newest;
for( ;; )
{
if( r->transfers[i].date < cutoff )
break;
bytes += r->transfers[i].size;
if( --i == -1 ) i = HISTORY_SIZE - 1; /* circular history */
if( i == r->newest ) break; /* we've come all the way around */
}
return (bytes/1024.0) * (1000.0/interval_msec);
}
/***
****
***/
tr_ratecontrol*
tr_rcInit( void )
{
tr_ratecontrol * r = tr_new0( tr_ratecontrol, 1 );
r->limit = 0;
return r;
}
void
tr_rcClose( tr_ratecontrol * r )
{
tr_rcReset( r );
tr_free( r );
}
/***
****
***/
size_t
tr_rcBytesLeft( const tr_ratecontrol * r )
{
size_t bytes = 0;
if( r != NULL )
{
const float cur = rateForInterval( r, SHORT_INTERVAL_MSEC );
const float max = r->limit;
const float kb = max>cur ? max-cur : 0;
bytes = (size_t)(kb * 1024);
}
return bytes;
}
float
tr_rcRate( const tr_ratecontrol * r )
{
float ret = 0.0f;
if( r )
ret = rateForInterval( r, LONG_INTERVAL_MSEC );
return ret;
}
/***
****
***/
void
tr_rcTransferred( tr_ratecontrol * r, size_t size )
{
const uint64_t now = tr_date ();
if( r->transfers[r->newest].date + GRANULARITY_MSEC >= now )
r->transfers[r->newest].size += size;
else {
if( ++r->newest == HISTORY_SIZE ) r->newest = 0;
r->transfers[r->newest].date = now;
r->transfers[r->newest].size = size;
}
}
void
tr_rcReset( tr_ratecontrol * r )
{
r->newest = 0;
memset( r->transfers, 0, sizeof(struct tr_transfer) * HISTORY_SIZE );
}
void
tr_rcSetLimit( tr_ratecontrol * r, int limit )
{
r->limit = limit;
}
int
tr_rcGetLimit( const tr_ratecontrol * r )
{
return r->limit;
}