📄 control_external.h
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/** * \file include/control_external.h * \brief External control plugin SDK * \author Takashi Iwai <tiwai@suse.de> * \date 2005 * * External control plugin SDK. *//* * 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 * */#ifndef __ALSA_CONTROL_EXTERNAL_H#define __ALSA_CONTROL_EXTERNAL_H#include "control.h"#ifdef __cplusplusextern "C" {#endif/** * \defgroup CtlPlugin_SDK External Control Plugin SDK * \{ *//** * Define the object entry for external control plugins */#define SND_CTL_PLUGIN_ENTRY(name) _snd_ctl_##name##_open/** * Define the symbols of the given control plugin with versions */#define SND_CTL_PLUGIN_SYMBOL(name) SND_DLSYM_BUILD_VERSION(SND_CTL_PLUGIN_ENTRY(name), SND_CONTROL_DLSYM_VERSION);/** * Define the control plugin */#define SND_CTL_PLUGIN_DEFINE_FUNC(plugin) \int SND_CTL_PLUGIN_ENTRY(plugin) (snd_ctl_t **handlep, const char *name,\ snd_config_t *root, snd_config_t *conf, int mode)/** External control plugin handle */typedef struct snd_ctl_ext snd_ctl_ext_t;/** Callback table of control ext */typedef struct snd_ctl_ext_callback snd_ctl_ext_callback_t;/** Key to access a control pointer */typedef unsigned long snd_ctl_ext_key_t;/* * Protocol version */#define SND_CTL_EXT_VERSION_MAJOR 1 /**< Protocol major version */#define SND_CTL_EXT_VERSION_MINOR 0 /**< Protocol minor version */#define SND_CTL_EXT_VERSION_TINY 0 /**< Protocol tiny version *//** * external plugin protocol version */#define SND_CTL_EXT_VERSION ((SND_CTL_EXT_VERSION_MAJOR<<16) |\ (SND_CTL_EXT_VERSION_MINOR<<8) |\ (SND_CTL_EXT_VERSION_TINY))/** Handle of control ext */struct snd_ctl_ext { /** * protocol version; #SND_CTL_EXT_VERSION must be filled here * before calling #snd_ctl_ext_create() */ unsigned int version; /** * Index of this card; must be filled before calling #snd_ctl_ext_create() */ int card_idx; /** * ID string of this card; must be filled before calling #snd_ctl_ext_create() */ char id[16]; /** * Driver name of this card; must be filled before calling #snd_ctl_ext_create() */ char driver[16]; /** * short name of this card; must be filled before calling #snd_ctl_ext_create() */ char name[32]; /** * Long name of this card; must be filled before calling #snd_ctl_ext_create() */ char longname[80]; /** * Mixer name of this card; must be filled before calling #snd_ctl_ext_create() */ char mixername[80]; /** * poll descriptor */ int poll_fd; /** * callbacks of this plugin; must be filled before calling #snd_pcm_ioplug_create() */ const snd_ctl_ext_callback_t *callback; /** * private data, which can be used freely in the driver callbacks */ void *private_data; /** * control handle filled by #snd_ctl_ext_create() */ snd_ctl_t *handle; int nonblock; /**< non-block mode; read-only */ int subscribed; /**< events subscribed; read-only */};/** Callback table of ext */struct snd_ctl_ext_callback { /** * close the control handle; optional */ void (*close)(snd_ctl_ext_t *ext); /** * return the total number of elements; required */ int (*elem_count)(snd_ctl_ext_t *ext); /** * return the element id of the given offset (array index); required */ int (*elem_list)(snd_ctl_ext_t *ext, unsigned int offset, snd_ctl_elem_id_t *id); /** * convert the element id to a search key; required */ snd_ctl_ext_key_t (*find_elem)(snd_ctl_ext_t *ext, const snd_ctl_elem_id_t *id); /** * the destructor of the key; optional */ void (*free_key)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key); /** * get the attribute of the element; required */ int (*get_attribute)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, int *type, unsigned int *acc, unsigned int *count); /** * get the element information of integer type */ int (*get_integer_info)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, long *imin, long *imax, long *istep); /** * get the element information of integer64 type */ int (*get_integer64_info)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, int64_t *imin, int64_t *imax, int64_t *istep); /** * get the element information of enumerated type */ int (*get_enumerated_info)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, unsigned int *items); /** * get the name of the enumerated item */ int (*get_enumerated_name)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, unsigned int item, char *name, size_t name_max_len); /** * read the current values of integer type */ int (*read_integer)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, long *value); /** * read the current values of integer64 type */ int (*read_integer64)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, int64_t *value); /** * read the current values of enumerated type */ int (*read_enumerated)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, unsigned int *items); /** * read the current values of bytes type */ int (*read_bytes)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, unsigned char *data, size_t max_bytes); /** * read the current values of iec958 type */ int (*read_iec958)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, snd_aes_iec958_t *iec958); /** * update the current values of integer type with the given values */ int (*write_integer)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, long *value); /** * update the current values of integer64 type with the given values */ int (*write_integer64)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, int64_t *value); /** * update the current values of enumerated type with the given values */ int (*write_enumerated)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, unsigned int *items); /** * update the current values of bytes type with the given values */ int (*write_bytes)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, unsigned char *data, size_t max_bytes); /** * update the current values of iec958 type with the given values */ int (*write_iec958)(snd_ctl_ext_t *ext, snd_ctl_ext_key_t key, snd_aes_iec958_t *iec958); /** * subscribe/unsubscribe the event notification; optional */ void (*subscribe_events)(snd_ctl_ext_t *ext, int subscribe); /** * read a pending notification event; optional */ int (*read_event)(snd_ctl_ext_t *ext, snd_ctl_elem_id_t *id, unsigned int *event_mask); /** * return the number of poll descriptors; optional */ int (*poll_descriptors_count)(snd_ctl_ext_t *ext); /** * fill the poll descriptors; optional */ int (*poll_descriptors)(snd_ctl_ext_t *ext, struct pollfd *pfds, unsigned int space); /** * mangle the revents of poll descriptors */ int (*poll_revents)(snd_ctl_ext_t *ext, struct pollfd *pfds, unsigned int nfds, unsigned short *revents);};/** * The access type bits stored in get_attribute callback */typedef enum snd_ctl_ext_access { SND_CTL_EXT_ACCESS_READ = (1<<0), SND_CTL_EXT_ACCESS_WRITE = (1<<1), SND_CTL_EXT_ACCESS_READWRITE = (3<<0), SND_CTL_EXT_ACCESS_VOLATILE = (1<<2), SND_CTL_EXT_ACCESS_INACTIVE = (1<<8),} snd_ctl_ext_access_t;/** * find_elem callback returns this if no matching control element is found */#define SND_CTL_EXT_KEY_NOT_FOUND (snd_ctl_ext_key_t)(-1)int snd_ctl_ext_create(snd_ctl_ext_t *ext, const char *name, int mode);int snd_ctl_ext_delete(snd_ctl_ext_t *ext);/** \} */#ifdef __cplusplus}#endif#endif /* __ALSA_CONTROL_EXTERNAL_H */
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