text: /*
   *   ALSA sequencer Ports 
   *   Copyright (c) 1998 by Frank van de Pol <fvdpol@coil.demon.nl>
   *
   *
   *   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
   *
   */
  #ifndef __SND_SEQ_PORTS_H
  #define __SND_SEQ_PORTS_H
  
  #include <sound/seq_kernel.h>
  #include "seq_lock.h"
  
  /* list of 'exported' ports */
  
  /* Client ports that are not exported are still accessible, but are
   anonymous ports. 
   
   If a port supports SUBSCRIPTION, that port can send events to all
   subscribersto a special address, with address
   (queue==SNDRV_SEQ_ADDRESS_SUBSCRIBERS). The message is then send to all
   recipients that are registered in the subscription list. A typical
   application for these SUBSCRIPTION events is handling of incoming MIDI
   data. The port doesn't 'know' what other clients are interested in this
   message. If for instance a MIDI recording application would like to receive
   the events from that port, it will first have to subscribe with that port.
   
  */
  
  struct snd_seq_subscribers {
  	struct snd_seq_port_subscribe info;	/* additional info */
  	struct list_head src_list;	/* link of sources */
  	struct list_head dest_list;	/* link of destinations */
  	atomic_t ref_count;
  };
  
  struct snd_seq_port_subs_info {
  	struct list_head list_head;	/* list of subscribed ports */
  	unsigned int count;		/* count of subscribers */
  	unsigned int exclusive: 1;	/* exclusive mode */
  	struct rw_semaphore list_mutex;
  	rwlock_t list_lock;
  	int (*open)(void *private_data, struct snd_seq_port_subscribe *info);
  	int (*close)(void *private_data, struct snd_seq_port_subscribe *info);
  };
  
  struct snd_seq_client_port {
  
  	struct snd_seq_addr addr;	/* client/port number */
  	struct module *owner;		/* owner of this port */
  	char name[64];			/* port name */	
  	struct list_head list;		/* port list */
  	snd_use_lock_t use_lock;
  
  	/* subscribers */
  	struct snd_seq_port_subs_info c_src;	/* read (sender) list */
  	struct snd_seq_port_subs_info c_dest;	/* write (dest) list */
  
  	int (*event_input)(struct snd_seq_event *ev, int direct, void *private_data,
  			   int atomic, int hop);
  	void (*private_free)(void *private_data);
  	void *private_data;
  	unsigned int closing : 1;
  	unsigned int timestamping: 1;
  	unsigned int time_real: 1;
  	int time_queue;
  	
  	/* capability, inport, output, sync */
  	unsigned int capability;	/* port capability bits */
  	unsigned int type;		/* port type bits */
  
  	/* supported channels */
  	int midi_channels;
  	int midi_voices;
  	int synth_voices;
  		
  };
  
  struct snd_seq_client;
  
  /* return pointer to port structure and lock port */
  struct snd_seq_client_port *snd_seq_port_use_ptr(struct snd_seq_client *client, int num);
  
  /* search for next port - port is locked if found */
  struct snd_seq_client_port *snd_seq_port_query_nearest(struct snd_seq_client *client,
  						       struct snd_seq_port_info *pinfo);
  
  /* unlock the port */
  #define snd_seq_port_unlock(port) snd_use_lock_free(&(port)->use_lock)
  
  /* create a port, port number is returned (-1 on failure) */
  struct snd_seq_client_port *snd_seq_create_port(struct snd_seq_client *client, int port_index);
  
  /* delete a port */
  int snd_seq_delete_port(struct snd_seq_client *client, int port);
  
  /* delete all ports */
  int snd_seq_delete_all_ports(struct snd_seq_client *client);
  
  /* set port info fields */
  int snd_seq_set_port_info(struct snd_seq_client_port *port,
  			  struct snd_seq_port_info *info);
  
  /* get port info fields */
  int snd_seq_get_port_info(struct snd_seq_client_port *port,
  			  struct snd_seq_port_info *info);
  
  /* add subscriber to subscription list */
  int snd_seq_port_connect(struct snd_seq_client *caller,
  			 struct snd_seq_client *s, struct snd_seq_client_port *sp,
  			 struct snd_seq_client *d, struct snd_seq_client_port *dp,
  			 struct snd_seq_port_subscribe *info);
  
  /* remove subscriber from subscription list */ 
  int snd_seq_port_disconnect(struct snd_seq_client *caller,
  			    struct snd_seq_client *s, struct snd_seq_client_port *sp,
  			    struct snd_seq_client *d, struct snd_seq_client_port *dp,
  			    struct snd_seq_port_subscribe *info);
  
  /* subscribe port */
  int snd_seq_port_subscribe(struct snd_seq_client_port *port,
  			   struct snd_seq_port_subscribe *info);
  
  /* get matched subscriber */
  int snd_seq_port_get_subscription(struct snd_seq_port_subs_info *src_grp,
  				  struct snd_seq_addr *dest_addr,
  				  struct snd_seq_port_subscribe *subs);
  
  #endif
  