multiload/src/netspeed.c


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#include <config.h>
#include <glib.h>
#include <time.h>

#include "netspeed.h"

enum { N_STATES = 4 };

struct _NetSpeed
{
    LoadGraph *graph;
    gulong states[N_STATES];
    size_t cur;
};

NetSpeed* netspeed_new(LoadGraph *g)
{
    NetSpeed *ns = g_new0(NetSpeed, 1);
    ns->graph = g;
    return ns;
}

void netspeed_delete(NetSpeed *ns)
{
    g_free(ns);
}

void netspeed_add(NetSpeed *ns, gulong tx)
{
    ns->cur = (ns->cur + 1) % N_STATES;
    ns->states[ns->cur] = tx;
}

/* Something very similar to g_format_size() but for rates.
 * This should give the same display as in g-s-m */
static char*
format_rate_for_display(guint rate)
{
    char *bytes;
    char *text;

    bytes = g_format_size (rate);
    text = g_strdup_printf (_("%s/s"), bytes);
    g_free (bytes);

    return text;
}

char* netspeed_get(NetSpeed *ns)
{
    gulong older, newer;
    guint rate;

    newer = ns->states[ns->cur];
    older = ns->states[(ns->cur + 1) % N_STATES];

    if ((older != 0) && (newer > older))
        rate = (newer - older) * 1000 / ((N_STATES - 1) * ns->graph->speed);
    else
        /* We end up here if we haven't got enough data yet or the
        network interface has jumped back (or there has never
        been any activity on any interface). A value of 0 is
        likely to be accurate, but if it is wrong it will be
        clearly wrong. In any event, it should fix itself in a
        few seconds. */
        rate = 0;

    return format_rate_for_display(rate);
}