/**

 * \file pcm/pcm_null.c

 * \ingroup PCM_Plugins

 * \brief PCM Null Plugin Interface

 * \author Abramo Bagnara <abramo@alsa-project.org>

 * \date 2000-2001

 */

/*

 *  PCM - Null plugin

 *  Copyright (c) 2000 by Abramo Bagnara <abramo@alsa-project.org>

 *

 *

 *   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 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 Lesser General Public License for more details.

 *

 *   You should have received a copy of the GNU Lesser General Public

 *   License along with this library; if not, write to the Free Software

 *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

 *

 */

#include "bswap.h"

#include <limits.h>

#include "pcm_local.h"

#include "pcm_plugin.h"

#ifndef PIC

/* entry for static linking */

const char *_snd_module_pcm_null = "";

#endif

#ifndef DOC_HIDDEN

typedef struct {

	snd_htimestamp_t trigger_tstamp;

	snd_pcm_state_t state;

	snd_pcm_uframes_t appl_ptr;

	snd_pcm_uframes_t hw_ptr;

	int poll_fd;

	snd_pcm_chmap_query_t **chmap;

} snd_pcm_null_t;

#endif

static int snd_pcm_null_close(snd_pcm_t *pcm)

{

	snd_pcm_null_t *null = pcm->private_data;

	close(null->poll_fd);

	free(null);

	return 0;

}

static int snd_pcm_null_nonblock(snd_pcm_t *pcm ATTRIBUTE_UNUSED, int nonblock ATTRIBUTE_UNUSED)

{

	return 0;

}

static int snd_pcm_null_async(snd_pcm_t *pcm ATTRIBUTE_UNUSED, int sig ATTRIBUTE_UNUSED, pid_t pid ATTRIBUTE_UNUSED)

{

	return -ENOSYS;

}

static int snd_pcm_null_info(snd_pcm_t *pcm, snd_pcm_info_t * info)

{

	memset(info, 0, sizeof(*info));

	info->stream = pcm->stream;

	info->card = -1;

	if (pcm->name) {

		snd_strlcpy((char *)info->id, pcm->name, sizeof(info->id));

		snd_strlcpy((char *)info->name, pcm->name, sizeof(info->name));

		snd_strlcpy((char *)info->subname, pcm->name, sizeof(info->subname));

	}

	info->subdevices_count = 1;

	return 0;

}

static snd_pcm_sframes_t snd_pcm_null_avail_update(snd_pcm_t *pcm)

{

	snd_pcm_null_t *null = pcm->private_data;

        if (null->state == SND_PCM_STATE_PREPARED) {

                /* it is required to return the correct avail count for */

                /* the prepared stream, otherwise the start is not called */

                return snd_pcm_mmap_avail(pcm);

        }

	return pcm->buffer_size;

}

static int snd_pcm_null_status(snd_pcm_t *pcm, snd_pcm_status_t * status)

{

	snd_pcm_null_t *null = pcm->private_data;

	memset(status, 0, sizeof(*status));

	status->state = null->state;

	status->trigger_tstamp = null->trigger_tstamp;

	status->appl_ptr = *pcm->appl.ptr;

	status->hw_ptr = *pcm->hw.ptr;

	gettimestamp(&status->tstamp, pcm->tstamp_type);

	status->avail = snd_pcm_null_avail_update(pcm);

	status->avail_max = pcm->buffer_size;

	return 0;

}

static snd_pcm_state_t snd_pcm_null_state(snd_pcm_t *pcm)

{

	snd_pcm_null_t *null = pcm->private_data;

	return null->state;

}

static int snd_pcm_null_hwsync(snd_pcm_t *pcm ATTRIBUTE_UNUSED)

{

	return 0;

}

static int snd_pcm_null_delay(snd_pcm_t *pcm ATTRIBUTE_UNUSED, snd_pcm_sframes_t *delayp)

{

	*delayp = 0;

	return 0;

}

static int snd_pcm_null_reset(snd_pcm_t *pcm)

{

	*pcm->appl.ptr = 0;

	*pcm->hw.ptr = 0;

	return 0;

}

static int snd_pcm_null_prepare(snd_pcm_t *pcm)

{

	snd_pcm_null_t *null = pcm->private_data;

	null->state = SND_PCM_STATE_PREPARED;

	return snd_pcm_null_reset(pcm);

}

static int snd_pcm_null_start(snd_pcm_t *pcm)

{

	snd_pcm_null_t *null = pcm->private_data;

	assert(null->state == SND_PCM_STATE_PREPARED);

	null->state = SND_PCM_STATE_RUNNING;

	if (pcm->stream == SND_PCM_STREAM_CAPTURE)

		*pcm->hw.ptr = *pcm->appl.ptr + pcm->buffer_size;

	else

		*pcm->hw.ptr = *pcm->appl.ptr;

	return 0;

}

static int snd_pcm_null_drop(snd_pcm_t *pcm)

{

	snd_pcm_null_t *null = pcm->private_data;

	assert(null->state != SND_PCM_STATE_OPEN);

	null->state = SND_PCM_STATE_SETUP;

	return 0;

}

static int snd_pcm_null_drain(snd_pcm_t *pcm)

{

	snd_pcm_null_t *null = pcm->private_data;

	assert(null->state != SND_PCM_STATE_OPEN);

	null->state = SND_PCM_STATE_SETUP;

	return 0;

}

static int snd_pcm_null_pause(snd_pcm_t *pcm, int enable)

{

	snd_pcm_null_t *null = pcm->private_data;

	if (enable) {

		if (null->state != SND_PCM_STATE_RUNNING)

			return -EBADFD;

		null->state = SND_PCM_STATE_PAUSED;

	} else {

		if (null->state != SND_PCM_STATE_PAUSED)

			return -EBADFD;

		null->state = SND_PCM_STATE_RUNNING;

	}

	return 0;

}

static snd_pcm_sframes_t snd_pcm_null_rewindable(snd_pcm_t *pcm)

{

	return pcm->buffer_size;

}

static snd_pcm_sframes_t snd_pcm_null_forwardable(snd_pcm_t *pcm ATTRIBUTE_UNUSED)

{

	return 0;

}

static snd_pcm_sframes_t snd_pcm_null_rewind(snd_pcm_t *pcm, snd_pcm_uframes_t frames)

{

	snd_pcm_null_t *null = pcm->private_data;

	switch (null->state) {

	case SND_PCM_STATE_RUNNING:

		snd_pcm_mmap_hw_backward(pcm, frames);

		/* Fall through */

	case SND_PCM_STATE_PREPARED:

		snd_pcm_mmap_appl_backward(pcm, frames);

		return frames;

	default:

		return -EBADFD;

	}

}

static snd_pcm_sframes_t snd_pcm_null_forward(snd_pcm_t *pcm, snd_pcm_uframes_t frames)

{

	snd_pcm_null_t *null = pcm->private_data;

	switch (null->state) {

	case SND_PCM_STATE_RUNNING:

		snd_pcm_mmap_hw_forward(pcm, frames);

		/* Fall through */

	case SND_PCM_STATE_PREPARED:

		snd_pcm_mmap_appl_forward(pcm, frames);

		return frames;

	default:

		return -EBADFD;

	}

}

static int snd_pcm_null_resume(snd_pcm_t *pcm ATTRIBUTE_UNUSED)

{

	return 0;

}

static snd_pcm_sframes_t snd_pcm_null_xfer_areas(snd_pcm_t *pcm,

						 const snd_pcm_channel_area_t *areas ATTRIBUTE_UNUSED,

						 snd_pcm_uframes_t offset ATTRIBUTE_UNUSED,

						 snd_pcm_uframes_t size)

{

	snd_pcm_mmap_appl_forward(pcm, size);

	snd_pcm_mmap_hw_forward(pcm, size);

	return size;

}

static snd_pcm_sframes_t snd_pcm_null_writei(snd_pcm_t *pcm, const void *buffer ATTRIBUTE_UNUSED, snd_pcm_uframes_t size)

{

	return snd_pcm_write_areas(pcm, NULL, 0, size, snd_pcm_null_xfer_areas);

}

static snd_pcm_sframes_t snd_pcm_null_writen(snd_pcm_t *pcm, void **bufs ATTRIBUTE_UNUSED, snd_pcm_uframes_t size)

{

	return snd_pcm_write_areas(pcm, NULL, 0, size, snd_pcm_null_xfer_areas);

}

static snd_pcm_sframes_t snd_pcm_null_readi(snd_pcm_t *pcm, void *buffer ATTRIBUTE_UNUSED, snd_pcm_uframes_t size)

{

	return snd_pcm_read_areas(pcm, NULL, 0, size, snd_pcm_null_xfer_areas);

}

static snd_pcm_sframes_t snd_pcm_null_readn(snd_pcm_t *pcm, void **bufs ATTRIBUTE_UNUSED, snd_pcm_uframes_t size)

{

	return snd_pcm_read_areas(pcm, NULL, 0, size, snd_pcm_null_xfer_areas);

}

static snd_pcm_sframes_t snd_pcm_null_mmap_commit(snd_pcm_t *pcm,

						  snd_pcm_uframes_t offset ATTRIBUTE_UNUSED,

						  snd_pcm_uframes_t size)

{

	return snd_pcm_null_forward(pcm, size);

}

static int snd_pcm_null_hw_refine(snd_pcm_t *pcm ATTRIBUTE_UNUSED, snd_pcm_hw_params_t *params)

{

	int err;

	/* Do not return a period size of 0 because for example portaudio cannot

	 * handle it.

	 */

	err = _snd_pcm_hw_param_set_min(params, SND_PCM_HW_PARAM_PERIOD_SIZE, 1,

					0);

	if (err < 0)

		return err;

	err = snd_pcm_hw_refine_soft(pcm, params);

	params->info = SND_PCM_INFO_MMAP | SND_PCM_INFO_MMAP_VALID |

		       SND_PCM_INFO_RESUME | SND_PCM_INFO_PAUSE;

	params->fifo_size = 0;

	return err;

}

static int snd_pcm_null_hw_params(snd_pcm_t *pcm ATTRIBUTE_UNUSED, snd_pcm_hw_params_t * params ATTRIBUTE_UNUSED)

{

	return 0;

}

static int snd_pcm_null_hw_free(snd_pcm_t *pcm ATTRIBUTE_UNUSED)

{

	return 0;

}

static int snd_pcm_null_sw_params(snd_pcm_t *pcm ATTRIBUTE_UNUSED, snd_pcm_sw_params_t * params ATTRIBUTE_UNUSED)

{

	return 0;

}

static snd_pcm_chmap_query_t **snd_pcm_null_query_chmaps(snd_pcm_t *pcm)

{

	snd_pcm_null_t *null = pcm->private_data;

	if (null->chmap)

		return _snd_pcm_copy_chmap_query(null->chmap);

	return NULL;

}

static snd_pcm_chmap_t *snd_pcm_null_get_chmap(snd_pcm_t *pcm)

{

	snd_pcm_null_t *null = pcm->private_data;

	if (null->chmap)

		return _snd_pcm_choose_fixed_chmap(pcm, null->chmap);

	return NULL;

}

static void snd_pcm_null_dump(snd_pcm_t *pcm, snd_output_t *out)

{

	snd_output_printf(out, "Null PCM\n");

	if (pcm->setup) {

		snd_output_printf(out, "Its setup is:\n");

		snd_pcm_dump_setup(pcm, out);

	}

}

static const snd_pcm_ops_t snd_pcm_null_ops = {

	.close = snd_pcm_null_close,

	.info = snd_pcm_null_info,

	.hw_refine = snd_pcm_null_hw_refine,

	.hw_params = snd_pcm_null_hw_params,

	.hw_free = snd_pcm_null_hw_free,

	.sw_params = snd_pcm_null_sw_params,

	.channel_info = snd_pcm_generic_channel_info,

	.dump = snd_pcm_null_dump,

	.nonblock = snd_pcm_null_nonblock,

	.async = snd_pcm_null_async,

	.mmap = snd_pcm_generic_mmap,

	.munmap = snd_pcm_generic_munmap,

	.query_chmaps = snd_pcm_null_query_chmaps,

	.get_chmap = snd_pcm_null_get_chmap,

	.set_chmap = NULL,

};

static const snd_pcm_fast_ops_t snd_pcm_null_fast_ops = {

	.status = snd_pcm_null_status,

	.state = snd_pcm_null_state,

	.hwsync = snd_pcm_null_hwsync,

	.delay = snd_pcm_null_delay,

	.prepare = snd_pcm_null_prepare,

	.reset = snd_pcm_null_reset,

	.start = snd_pcm_null_start,

	.drop = snd_pcm_null_drop,

	.drain = snd_pcm_null_drain,

	.pause = snd_pcm_null_pause,

	.rewindable = snd_pcm_null_rewindable,

	.rewind = snd_pcm_null_rewind,

	.forwardable = snd_pcm_null_forwardable,

	.forward = snd_pcm_null_forward,

	.resume = snd_pcm_null_resume,

	.writei = snd_pcm_null_writei,

	.writen = snd_pcm_null_writen,

	.readi = snd_pcm_null_readi,

	.readn = snd_pcm_null_readn,

	.avail_update = snd_pcm_null_avail_update,

	.mmap_commit = snd_pcm_null_mmap_commit,

	.htimestamp = snd_pcm_generic_real_htimestamp,

};

/**

 * \brief Creates a new null PCM

 * \param pcmp Returns created PCM handle

 * \param name Name of PCM

 * \param stream Stream type

 * \param mode Stream mode

 * \retval zero on success otherwise a negative error code

 * \warning Using of this function might be dangerous in the sense

 *          of compatibility reasons. The prototype might be freely

 *          changed in future.

 */

int snd_pcm_null_open(snd_pcm_t **pcmp, const char *name, snd_pcm_stream_t stream, int mode)

{

	snd_pcm_t *pcm;

	snd_pcm_null_t *null;

	int fd;

	int err;

	assert(pcmp);

	if (stream == SND_PCM_STREAM_PLAYBACK) {

		fd = open("/dev/null", O_WRONLY);

		if (fd < 0) {

			SYSERR("Cannot open /dev/null");

			return -errno;

		}

	} else {

		fd = open("/dev/full", O_RDONLY);

		if (fd < 0) {

			SYSERR("Cannot open /dev/full");

			return -errno;

		}

	}

	null = calloc(1, sizeof(snd_pcm_null_t));

	if (!null) {

		close(fd);

		return -ENOMEM;

	}

	null->poll_fd = fd;

	null->state = SND_PCM_STATE_OPEN;

	err = snd_pcm_new(&pcm, SND_PCM_TYPE_NULL, name, stream, mode);

	if (err < 0) {

		close(fd);

		free(null);

		return err;

	}

	pcm->ops = &snd_pcm_null_ops;

	pcm->fast_ops = &snd_pcm_null_fast_ops;

	pcm->private_data = null;

	pcm->poll_fd = fd;

	pcm->poll_events = stream == SND_PCM_STREAM_PLAYBACK ? POLLOUT : POLLIN;

	snd_pcm_set_hw_ptr(pcm, &null->hw_ptr, -1, 0);

	snd_pcm_set_appl_ptr(pcm, &null->appl_ptr, -1, 0);

	*pcmp = pcm;

	return 0;

}

/*! \page pcm_plugins

\section pcm_plugins_null Plugin: Null

This plugin discards contents of a PCM stream or creates a stream with zero

samples.

Note: This implementation uses devices /dev/null (playback, must be writable)

and /dev/full (capture, must be readable).

\code

pcm.name {

        type null               # Null PCM

	[chmap MAP]		# Provide channel maps; MAP is a string array

}

\endcode

\subsection pcm_plugins_null_funcref Function reference

  
snd_pcm_null_open()

  
_snd_pcm_null_open()

*/

/**

 * \brief Creates a new Null PCM

 * \param pcmp Returns created PCM handle

 * \param name Name of PCM

 * \param root Root configuration node

 * \param conf Configuration node with Null PCM description

 * \param stream Stream type

 * \param mode Stream mode

 * \retval zero on success otherwise a negative error code

 * \warning Using of this function might be dangerous in the sense

 *          of compatibility reasons. The prototype might be freely

 *          changed in future.

 */

int _snd_pcm_null_open(snd_pcm_t **pcmp, const char *name,

		       snd_config_t *root ATTRIBUTE_UNUSED, snd_config_t *conf, 

		       snd_pcm_stream_t stream, int mode)

{

	snd_config_iterator_t i, next;

	snd_pcm_null_t *null;

	snd_pcm_chmap_query_t **chmap = NULL;

	int err;

	snd_config_for_each(i, next, conf) {

		snd_config_t *n = snd_config_iterator_entry(i);

		const char *id;

		if (snd_config_get_id(n, &id) < 0)

			continue;

		if (snd_pcm_conf_generic_id(id))

			continue;

		if (strcmp(id, "chmap") == 0) {

			snd_pcm_free_chmaps(chmap);

			chmap = _snd_pcm_parse_config_chmaps(n);

			if (!chmap) {

				SNDERR("Invalid channel map for %s", id);

				return -EINVAL;

			}

			continue;

		}

		SNDERR("Unknown field %s", id);

		snd_pcm_free_chmaps(chmap);

		return -EINVAL;

	}

	err = snd_pcm_null_open(pcmp, name, stream, mode);

	if (err < 0) {

		snd_pcm_free_chmaps(chmap);

		return err;

	}

	null = (*pcmp)->private_data;

	null->chmap = chmap;

	return 0;

}

#ifndef DOC_HIDDEN

SND_DLSYM_BUILD_VERSION(_snd_pcm_null_open, SND_PCM_DLSYM_VERSION);

#endif