text: /**
   * \file pcm/pcm_copy.c
   * \ingroup PCM_Plugins
   * \brief PCM Copy Plugin Interface
   * \author Abramo Bagnara <abramo@alsa-project.org>
   * \date 2000-2001
   */
  /*
   *  PCM - Copy conversion
   *  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., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
   *
   */
    
  #include <byteswap.h>
  #include "pcm_local.h"
  #include "pcm_plugin.h"
  
  #ifndef PIC
  /* entry for static linking */
  const char *_snd_module_pcm_copy = "";
  #endif
  
  #ifndef DOC_HIDDEN
  typedef struct {
  	/* This field need to be the first */
  	snd_pcm_plugin_t plug;
  } snd_pcm_copy_t;
  #endif
  
  static int snd_pcm_copy_hw_refine_cprepare(snd_pcm_t *pcm ATTRIBUTE_UNUSED, snd_pcm_hw_params_t *params)
  {
  	int err;
  	snd_pcm_access_mask_t access_mask = { SND_PCM_ACCBIT_SHM };
  	err = _snd_pcm_hw_param_set_mask(params, SND_PCM_HW_PARAM_ACCESS,
  					 &access_mask);
  	if (err < 0)
  		return err;
  	params->info &= ~(SND_PCM_INFO_MMAP | SND_PCM_INFO_MMAP_VALID);
  	return 0;
  }
  
  static int snd_pcm_copy_hw_refine_sprepare(snd_pcm_t *pcm ATTRIBUTE_UNUSED, snd_pcm_hw_params_t *sparams)
  {
  	snd_pcm_access_mask_t saccess_mask = { SND_PCM_ACCBIT_MMAP };
  	_snd_pcm_hw_params_any(sparams);
  	_snd_pcm_hw_param_set_mask(sparams, SND_PCM_HW_PARAM_ACCESS,
  				   &saccess_mask);
  	return 0;
  }
  
  static int snd_pcm_copy_hw_refine_schange(snd_pcm_t *pcm ATTRIBUTE_UNUSED, snd_pcm_hw_params_t *params,
  					  snd_pcm_hw_params_t *sparams)
  {
  	int err;
  	unsigned int links = ~SND_PCM_HW_PARBIT_ACCESS;
  	err = _snd_pcm_hw_params_refine(sparams, links, params);
  	if (err < 0)
  		return err;
  	return 0;
  }
  	
  static int snd_pcm_copy_hw_refine_cchange(snd_pcm_t *pcm ATTRIBUTE_UNUSED, snd_pcm_hw_params_t *params,
  					  snd_pcm_hw_params_t *sparams)
  {
  	int err;
  	unsigned int links = ~SND_PCM_HW_PARBIT_ACCESS;
  	err = _snd_pcm_hw_params_refine(params, links, sparams);
  	if (err < 0)
  		return err;
  	return 0;
  }
  
  static int snd_pcm_copy_hw_refine(snd_pcm_t *pcm, snd_pcm_hw_params_t *params)
  {
  	return snd_pcm_hw_refine_slave(pcm, params,
  				       snd_pcm_copy_hw_refine_cprepare,
  				       snd_pcm_copy_hw_refine_cchange,
  				       snd_pcm_copy_hw_refine_sprepare,
  				       snd_pcm_copy_hw_refine_schange,
  				       snd_pcm_generic_hw_refine);
  }
  
  static int snd_pcm_copy_hw_params(snd_pcm_t *pcm, snd_pcm_hw_params_t *params)
  {
  	return snd_pcm_hw_params_slave(pcm, params,
  				       snd_pcm_copy_hw_refine_cchange,
  				       snd_pcm_copy_hw_refine_sprepare,
  				       snd_pcm_copy_hw_refine_schange,
  				       snd_pcm_generic_hw_params);
  }
  
  static snd_pcm_uframes_t
  snd_pcm_copy_write_areas(snd_pcm_t *pcm,
  			 const snd_pcm_channel_area_t *areas,
  			 snd_pcm_uframes_t offset,
  			 snd_pcm_uframes_t size,
  			 const snd_pcm_channel_area_t *slave_areas,
  			 snd_pcm_uframes_t slave_offset,
  			 snd_pcm_uframes_t *slave_sizep)
  {
  	if (size > *slave_sizep)
  		size = *slave_sizep;
  	snd_pcm_areas_copy(slave_areas, slave_offset,
  			   areas, offset,
  			   pcm->channels, size, pcm->format);
  	*slave_sizep = size;
  	return size;
  }
  
  static snd_pcm_uframes_t
  snd_pcm_copy_read_areas(snd_pcm_t *pcm,
  			const snd_pcm_channel_area_t *areas,
  			snd_pcm_uframes_t offset,
  			snd_pcm_uframes_t size,
  			const snd_pcm_channel_area_t *slave_areas,
  			snd_pcm_uframes_t slave_offset,
  			snd_pcm_uframes_t *slave_sizep)
  {
  	if (size > *slave_sizep)
  		size = *slave_sizep;
  	snd_pcm_areas_copy(areas, offset, 
  			   slave_areas, slave_offset,
  			   pcm->channels, size, pcm->format);
  	*slave_sizep = size;
  	return size;
  }
  
  static void snd_pcm_copy_dump(snd_pcm_t *pcm, snd_output_t *out)
  {
  	snd_pcm_copy_t *copy = pcm->private_data;
  	snd_output_printf(out, "Copy conversion PCM\n");
  	if (pcm->setup) {
  		snd_output_printf(out, "Its setup is:\n");
  		snd_pcm_dump_setup(pcm, out);
  	}
  	snd_output_printf(out, "Slave: ");
  	snd_pcm_dump(copy->plug.gen.slave, out);
  }
  
  static const snd_pcm_ops_t snd_pcm_copy_ops = {
  	.close = snd_pcm_generic_close,
  	.info = snd_pcm_generic_info,
  	.hw_refine = snd_pcm_copy_hw_refine,
  	.hw_params = snd_pcm_copy_hw_params,
  	.hw_free = snd_pcm_generic_hw_free,
  	.sw_params = snd_pcm_generic_sw_params,
  	.channel_info = snd_pcm_generic_channel_info,
  	.dump = snd_pcm_copy_dump,
  	.nonblock = snd_pcm_generic_nonblock,
  	.async = snd_pcm_generic_async,
  	.mmap = snd_pcm_generic_mmap,
  	.munmap = snd_pcm_generic_munmap,
  	.query_chmaps = snd_pcm_generic_query_chmaps,
  	.get_chmap = snd_pcm_generic_get_chmap,
  	.set_chmap = snd_pcm_generic_set_chmap,
  };
  
  /**
   * \brief Creates a new copy PCM
   * \param pcmp Returns created PCM handle
   * \param name Name of PCM
   * \param slave Slave PCM handle
   * \param close_slave When set, the slave PCM handle is closed with copy PCM
   * \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_copy_open(snd_pcm_t **pcmp, const char *name, snd_pcm_t *slave, int close_slave)
  {
  	snd_pcm_t *pcm;
  	snd_pcm_copy_t *copy;
  	int err;
  	assert(pcmp && slave);
  	copy = calloc(1, sizeof(snd_pcm_copy_t));
  	if (!copy) {
  		return -ENOMEM;
  	}
  	snd_pcm_plugin_init(&copy->plug);
  	copy->plug.read = snd_pcm_copy_read_areas;
  	copy->plug.write = snd_pcm_copy_write_areas;
  	copy->plug.undo_read = snd_pcm_plugin_undo_read_generic;
  	copy->plug.undo_write = snd_pcm_plugin_undo_write_generic;
  	copy->plug.gen.slave = slave;
  	copy->plug.gen.close_slave = close_slave;
  
  	err = snd_pcm_new(&pcm, SND_PCM_TYPE_COPY, name, slave->stream, slave->mode);
  	if (err < 0) {
  		free(copy);
  		return err;
  	}
  	pcm->ops = &snd_pcm_copy_ops;
  	pcm->fast_ops = &snd_pcm_plugin_fast_ops;
  	pcm->private_data = copy;
  	pcm->poll_fd = slave->poll_fd;
  	pcm->poll_events = slave->poll_events;
  	pcm->tstamp_type = slave->tstamp_type;
  	snd_pcm_set_hw_ptr(pcm, &copy->plug.hw_ptr, -1, 0);
  	snd_pcm_set_appl_ptr(pcm, &copy->plug.appl_ptr, -1, 0);
  	*pcmp = pcm;
  
  	return 0;
  }
  
  /*! \page pcm_plugins
  
  \section pcm_plugins_copy Plugin: copy
  
  This plugin copies samples from master copy PCM to given slave PCM.
  The channel count, format and rate must match for both of them. 
  
  \code
  pcm.name {
  	type copy		# Copy PCM
  	slave STR		# Slave name
  	# or
  	slave {			# Slave definition
  		pcm STR		# Slave PCM name
  		# or
  		pcm { }		# Slave PCM definition
  	}
  }
  \endcode
  
  \subsection pcm_plugins_copy_funcref Function reference
  
  <UL>
    <LI>snd_pcm_copy_open()
    <LI>_snd_pcm_copy_open()
  </UL>
  
  */
  
  /**
   * \brief Creates a new copy PCM
   * \param pcmp Returns created PCM handle
   * \param name Name of PCM
   * \param root Root configuration node
   * \param conf Configuration node with copy 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_copy_open(snd_pcm_t **pcmp, const char *name,
  		       snd_config_t *root, snd_config_t *conf, 
  		       snd_pcm_stream_t stream, int mode)
  {
  	snd_config_iterator_t i, next;
  	int err;
  	snd_pcm_t *spcm;
  	snd_config_t *slave = NULL, *sconf;
  	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, "slave") == 0) {
  			slave = n;
  			continue;
  		}
  		SNDERR("Unknown field %s", id);
  		return -EINVAL;
  	}
  	if (!slave) {
  		SNDERR("slave is not defined");
  		return -EINVAL;
  	}
  	err = snd_pcm_slave_conf(root, slave, &sconf, 0);
  	if (err < 0)
  		return err;
  	err = snd_pcm_open_slave(&spcm, root, sconf, stream, mode, conf);
  	snd_config_delete(sconf);
  	if (err < 0)
  		return err;
  	err = snd_pcm_copy_open(pcmp, name, spcm, 1);
  	if (err < 0)
  		snd_pcm_close(spcm);
  	return err;
  }
  #ifndef DOC_HIDDEN
  SND_DLSYM_BUILD_VERSION(_snd_pcm_copy_open, SND_PCM_DLSYM_VERSION);
  #endif
  