/***************************************************************************** * bandwidth.c ***************************************************************************** * Copyright ? 2007 Rémi Denis-Courmont * $Id$ * * This program 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 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., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA. *****************************************************************************/#ifdef HAVE_CONFIG_H# include "config.h"#endif#include <vlc_common.h>#include <vlc_plugin.h>#include <assert.h>#include <errno.h>#include <vlc_access.h>#define BANDWIDTH_TEXT N_("Bandwidth limit (bytes/s)")#define BANDWIDTH_LONGTEXT N_( \    "The bandwidth module will drop any data in excess of that many bytes " \    "per seconds." )static int  Open (vlc_object_t *);static void Close (vlc_object_t *);/* TODO: burst support */vlc_module_begin ();    set_shortname (N_("Bandwidth"));    set_description (N_("Bandwidth limiter"));    set_category (CAT_INPUT);    set_subcategory (SUBCAT_INPUT_ACCESS_FILTER);    set_capability ("access_filter", 0);    add_shortcut ("bandwidth");    set_callbacks (Open, Close);    add_integer ("access-bandwidth", 65536, NULL, BANDWIDTH_TEXT,                 BANDWIDTH_LONGTEXT, false);vlc_module_end();static ssize_t Read (access_t *access, uint8_t *buffer, size_t len);static int Seek (access_t *access, int64_t offset);static int Control (access_t *access, int cmd, va_list ap);struct access_sys_t{    mtime_t last_time;    size_t  last_size;    size_t  bandwidth;};/** * Open() */static int Open (vlc_object_t *obj){    access_t *access = (access_t*)obj;    access_t *src = access->p_source;    if (src->pf_read != NULL)        access->pf_read = Read;    else    {        msg_Err (obj, "block bandwidth limit not implemented");        return VLC_EGENERIC;    }    if (src->pf_seek != NULL)        access->pf_seek = Seek;    access->pf_control = Control;    access->info = src->info;    access_sys_t *p_sys = access->p_sys = malloc (sizeof (*p_sys));    if (p_sys == NULL)        return VLC_ENOMEM;    memset (p_sys, 0, sizeof (*p_sys));    p_sys->bandwidth = var_CreateGetInteger (access, "access-bandwidth");    p_sys->last_time = mdate ();    msg_Dbg (obj, "bandwidth limit: %lu bytes/s",             (unsigned long)p_sys->bandwidth);    return VLC_SUCCESS;}/** * Close() */static void Close (vlc_object_t *obj){    access_t *access = (access_t *)obj;    access_sys_t *p_sys = access->p_sys;    free (p_sys);}static ssize_t Read (access_t *access, uint8_t *buffer, size_t len){    access_t *src = access->p_source;    access_sys_t *p_sys = access->p_sys;    mtime_t now;    if (len == 0)        return 0;retry:    now = mdate ();    if (now <= p_sys->last_time)    {        msg_Err (access, "*** ALERT *** System clock is going backward! ***");        return 0; /* Uho, your clock is broken. */    }    mtime_t delta = now - p_sys->last_time;    p_sys->last_time = now;    delta *= p_sys->bandwidth;    delta /= 1000000u;    if (delta == 0)    {        now += 1000000u / p_sys->bandwidth;        mwait (now);        goto retry;    }    if (len > delta)    {        msg_Dbg (access, "reading %"PRIu64" bytes instead of %zu", delta,                 len);        len = (int)delta;    }    src->info.i_update = access->info.i_update;    len = src->pf_read (src, buffer, len);    access->info = src->info;    msg_Dbg (access, "read %zu bytes", len);    return len;}static int Control (access_t *access, int cmd, va_list ap){    access_t *src = access->p_source;    return src->pf_control (src, cmd, ap);}static int Seek (access_t *access, int64_t offset){    access_t *src = access->p_source;    src->info.i_update = access->info.i_update;    int ret = src->pf_seek (src, offset);    access->info = src->info;    return ret;}