transmission/libtransmission/history.c

87 lines
1.8 KiB
C

/*
* This file Copyright (C) 2010 Mnemosyne LLC
*
* This file is licensed by the GPL version 2. Works owned by the
* Transmission project are granted a special exemption to clause 2(b)
* so that the bulk of its code can remain under the MIT license.
* This exemption does not extend to derived works not owned by
* the Transmission project.
*
* $Id$
*/
#include <assert.h>
#include "transmission.h"
#include "history.h"
#include "utils.h"
struct history_slice
{
unsigned int n;
time_t date;
};
struct tr_recentHistory
{
int newest;
int sliceCount;
unsigned int precision;
struct history_slice * slices;
};
void
tr_historyAdd( tr_recentHistory * h, time_t now, unsigned int n )
{
if( h->slices[h->newest].date + h->precision >= now )
h->slices[h->newest].n += n;
else {
if( ++h->newest == h->sliceCount ) h->newest = 0;
h->slices[h->newest].date = now;
h->slices[h->newest].n = n;
}
}
unsigned int
tr_historyGet( const tr_recentHistory * h, time_t now, unsigned int sec )
{
unsigned int n = 0;
const time_t cutoff = (now?now:tr_time()) - sec;
int i = h->newest;
for( ;; )
{
if( h->slices[i].date <= cutoff )
break;
n += h->slices[i].n;
if( --i == -1 ) i = h->sliceCount - 1; /* circular history */
if( i == h->newest ) break; /* we've come all the way around */
}
return n;
}
tr_recentHistory *
tr_historyNew( unsigned int seconds, unsigned int precision )
{
tr_recentHistory * h;
assert( precision <= seconds );
h = tr_new0( tr_recentHistory, 1 );
h->precision = precision;
h->sliceCount = seconds / precision;
h->slices = tr_new0( struct history_slice, h->sliceCount );
return h;
}
void
tr_historyFree( tr_recentHistory * h )
{
tr_free( h->slices );
tr_free( h );
}