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/* BSE - Better Sound Engine
* Copyright (C) 2004 Tim Janik
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* A copy of the GNU Lesser General Public License should ship along
* with this library; if not, see http://www.gnu.org/copyleft/.
*/
#include "bsepcmdevice-null.h"
#include "bsesequencer.h"
#include "bseengine.h"
#include <string.h>
static SFI_MSG_TYPE_DEFINE (debug_pcm, "pcm", SFI_MSG_DEBUG, NULL);
#define DEBUG(...) sfi_debug (debug_pcm, __VA_ARGS__)
typedef struct
{
BsePcmHandle handle;
guint busy_us;
guint sleep_us;
} NullHandle;
/* --- prototypes --- */
static gsize null_device_read (BsePcmHandle *handle,
gfloat *values);
static void null_device_write (BsePcmHandle *handle,
const gfloat *values);
static gboolean null_device_check_io (BsePcmHandle *handle,
glong *timeoutp);
static guint null_device_latency (BsePcmHandle *handle);
/* --- functions --- */
static void
bse_pcm_device_null_init (BsePcmDeviceNull *null)
{
}
static SfiRing*
bse_pcm_device_null_list_devices (BseDevice *device)
{
SfiRing *ring = NULL;
ring = sfi_ring_append (ring, bse_device_entry_new (device, g_strdup_printf ("default"), NULL));
return ring;
}
static BseErrorType
bse_pcm_device_null_open (BseDevice *device,
gboolean require_readable,
gboolean require_writable,
guint n_args,
const gchar **args)
{
NullHandle *null = g_new0 (NullHandle, 1);
BsePcmHandle *handle = &null->handle;
/* setup request */
handle->readable = require_readable;
handle->writable = require_writable;
handle->n_channels = 2;
handle->mix_freq = BSE_PCM_DEVICE (device)->req_mix_freq;
bse_device_set_opened (device, "null", handle->readable, handle->writable);
handle->read = null_device_read;
handle->write = null_device_write;
handle->check_io = null_device_check_io;
handle->latency = null_device_latency;
null->busy_us = 0;
if (n_args == 1 && strcmp (args[0], "nosleep") == 0)
null->sleep_us = 0;
else
null->sleep_us = 10 * 1000;
BSE_PCM_DEVICE (device)->handle = handle;
DEBUG ("NULL: opening PCM readable=%d writable=%d: %s", require_readable, require_writable, bse_error_blurb (BSE_ERROR_NONE));
return BSE_ERROR_NONE;
}
static void
bse_pcm_device_null_close (BseDevice *device)
{
NullHandle *null = (NullHandle*) BSE_PCM_DEVICE (device)->handle;
BSE_PCM_DEVICE (device)->handle = NULL;
g_free (null);
}
static gboolean
null_device_check_io (BsePcmHandle *handle,
glong *timeoutp)
{
/* keep the sequencer busy or we will constantly timeout */
sfi_thread_wakeup (bse_sequencer_thread);
*timeoutp = 1;
/* ensure sequencer fairness */
return !bse_sequencer_thread_lagging (2);
}
static guint
null_device_latency (BsePcmHandle *handle)
{
/* total latency in frames */
return handle->mix_freq / 10;
}
static gsize
null_device_read (BsePcmHandle *handle,
gfloat *values)
{
const gsize n_values = handle->n_channels * handle->block_length;
memset (values, 0, sizeof (values[0]) * n_values);
return n_values;
}
static void
null_device_write (BsePcmHandle *handle,
const gfloat *values)
{
NullHandle *null = (NullHandle*) handle;
null->busy_us += handle->block_length * 1000000 / handle->mix_freq;
if (null->busy_us >= 100 * 1000)
{
null->busy_us = 0;
/* give cpu to other applications (we might run at nice level -20) */
if (null->sleep_us)
g_usleep (null->sleep_us);
}
}
static void
bse_pcm_device_null_class_init (BsePcmDeviceNullClass *class)
{
BseDeviceClass *device_class = BSE_DEVICE_CLASS (class);
device_class->list_devices = bse_pcm_device_null_list_devices;
bse_device_class_setup (device_class,
-1,
"null",
_("[nosleep]"), /* syntax */
/* TRANSLATORS: keep this text to 70 chars in width */
_("Discard all PCM output and provide zero blocks as input. This\n"
"driver is not part of the automatic PCM device selection list.\n"
"Normally the null driver sleeps regularily to give CPU cycles to\n"
"other apps, which is helpful when running at high priority.\n"
"Sleeping can be disabled by passing \"nosleep\" as option.\n"));
device_class->open = bse_pcm_device_null_open;
device_class->close = bse_pcm_device_null_close;
}
BSE_BUILTIN_TYPE (BsePcmDeviceNull)
{
GType pcm_device_null_type;
static const GTypeInfo pcm_device_null_info = {
sizeof (BsePcmDeviceNullClass),
(GBaseInitFunc) NULL,
(GBaseFinalizeFunc) NULL,
(GClassInitFunc) bse_pcm_device_null_class_init,
(GClassFinalizeFunc) NULL,
NULL /* class_data */,
sizeof (BsePcmDeviceNull),
0 /* n_preallocs */,
(GInstanceInitFunc) bse_pcm_device_null_init,
};
pcm_device_null_type = bse_type_register_static (BSE_TYPE_PCM_DEVICE,
"BsePcmDeviceNull",
"Null PCM device implementation",
__FILE__, __LINE__,
&pcm_device_null_info);
return pcm_device_null_type;
}
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