231 lines
8.5 KiB
C
231 lines
8.5 KiB
C
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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*
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* Copyright (C) 2016 Amaury Pouly
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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#include "alsa-controls.h"
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#include "panic.h"
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#include <stdlib.h>
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/* alsa control handle, we keep it open at all times */
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static snd_ctl_t *alsa_ctl;
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/* list of all controls, we allocate and fill it once, so we can easily lookup */
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static snd_ctl_elem_list_t *alsa_ctl_list;
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void alsa_controls_init(void)
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{
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snd_ctl_elem_info_t *info;
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/* allocate list on heap because it is used it is used in other functions */
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snd_ctl_elem_list_malloc(&alsa_ctl_list);
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/* allocate info on stack so there is no need to free them */
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snd_ctl_elem_info_alloca(&info);
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/* there is only one card and "default" always works */
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if(snd_ctl_open(&alsa_ctl, "default", 0) < 0)
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panicf("Cannot open ctl\n");
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/* ALSA is braindead: first "get" the list -> only retrieve count */
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if(snd_ctl_elem_list(alsa_ctl, alsa_ctl_list) < 0)
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panicf("Cannot get element list\n");
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/* now we can allocate the list since the know the size */
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int count = snd_ctl_elem_list_get_count(alsa_ctl_list);
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if(snd_ctl_elem_list_alloc_space(alsa_ctl_list, count) < 0)
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panicf("Cannot allocate space for element list\n");
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/* ... and get the list again! */
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if(snd_ctl_elem_list(alsa_ctl, alsa_ctl_list) < 0)
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panicf("Cannot get element list\n");
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}
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void alsa_controls_close(void)
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{
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snd_ctl_close(alsa_ctl);
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}
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/* find a control element ID by name, return false of not found, the id needs
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* to be allocated */
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bool alsa_controls_find(snd_ctl_elem_id_t *id, const char *name)
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{
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/* ALSA identifies controls by "id"s, it almost makes sense, except ids
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* are a horrible opaque structure */
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int count = snd_ctl_elem_list_get_count(alsa_ctl_list);
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/* enumerate controls */
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for(int i = 0; i < count; i++)
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{
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snd_ctl_elem_list_get_id(alsa_ctl_list, i, id);
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if(strcmp(snd_ctl_elem_id_get_name(id), name) == 0)
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return true;
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}
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/* not found */
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return false;
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}
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bool alsa_has_control(const char *name)
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{
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snd_ctl_elem_id_t *id;
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/* allocate things on stack */
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snd_ctl_elem_id_alloca(&id);
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/* find control */
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return alsa_controls_find(id, name);
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}
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/* find a control element enum index by name, return -1 if not found */
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int alsa_controls_find_enum(const char *name, const char *enum_name)
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{
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snd_ctl_elem_id_t *id;
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snd_ctl_elem_info_t *info;
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/* allocate things on stack to speedup */
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snd_ctl_elem_id_alloca(&id);
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snd_ctl_elem_info_alloca(&info);
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/* find control */
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if(!alsa_controls_find(id, name))
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panicf("Cannot find control '%s'", name);
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snd_ctl_elem_info_set_id(info, id);
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if(snd_ctl_elem_info(alsa_ctl, info) < 0)
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panicf("Cannot get control '%s' info", name);
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/* list items */
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unsigned count = snd_ctl_elem_info_get_items(info);
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for(unsigned i = 0; i < count; i++)
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{
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snd_ctl_elem_info_set_item(info, i);
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if(snd_ctl_elem_info(alsa_ctl, info) < 0)
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panicf("Cannot get control '%s' info for item %u", name, i);
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if(strcmp(snd_ctl_elem_info_get_item_name(info), enum_name) == 0)
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return i;
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}
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return -1;
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}
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/* set/get a control, potentially supports several values */
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void alsa_controls_get_set(bool get, const char *name, snd_ctl_elem_type_t type,
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unsigned nr_values, long *val)
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{
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snd_ctl_elem_id_t *id;
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snd_ctl_elem_info_t *info;
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snd_ctl_elem_value_t *value;
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/* allocate things on stack to speedup */
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snd_ctl_elem_id_alloca(&id);
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snd_ctl_elem_info_alloca(&info);
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snd_ctl_elem_value_alloca(&value);
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/* find control */
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if(!alsa_controls_find(id, name))
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panicf("Cannot find control '%s'", name);
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/* check the type of the control */
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snd_ctl_elem_info_set_id(info, id);
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if(snd_ctl_elem_info(alsa_ctl, info) < 0)
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panicf("Cannot get control '%s' info", name);
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if(snd_ctl_elem_info_get_type(info) != type)
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panicf("Control '%s' has wrong type (got %d, expected %d", name,
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snd_ctl_elem_info_get_type(info), type);
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if(snd_ctl_elem_info_get_count(info) != nr_values)
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panicf("Control '%s' has wrong count (got %u, expected %u)",
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name, snd_ctl_elem_info_get_count(info), nr_values);
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snd_ctl_elem_value_set_id(value, id);
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/* set value */
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if(get)
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{
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/* read value */
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if(snd_ctl_elem_read(alsa_ctl, value) < 0)
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panicf("Cannot read control '%s'", name);
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for(unsigned i = 0; i < nr_values; i++)
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{
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/* ALSA is braindead: there are "typed" setters but they all take long anyway */
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if(type == SND_CTL_ELEM_TYPE_BOOLEAN)
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val[i] = snd_ctl_elem_value_get_boolean(value, i);
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else if(type == SND_CTL_ELEM_TYPE_INTEGER)
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val[i] = snd_ctl_elem_value_get_integer(value, i);
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else if(type == SND_CTL_ELEM_TYPE_ENUMERATED)
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val[i] = snd_ctl_elem_value_get_enumerated(value, i);
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}
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}
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else
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{
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for(unsigned i = 0; i < nr_values; i++)
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{
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/* ALSA is braindead: there are "typed" setters but they all take long anyway */
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if(type == SND_CTL_ELEM_TYPE_BOOLEAN)
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snd_ctl_elem_value_set_boolean(value, i, val[i]);
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else if(type == SND_CTL_ELEM_TYPE_INTEGER)
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snd_ctl_elem_value_set_integer(value, i, val[i]);
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else if(type == SND_CTL_ELEM_TYPE_ENUMERATED)
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snd_ctl_elem_value_set_enumerated(value, i, val[i]);
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}
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/* write value */
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if(snd_ctl_elem_write(alsa_ctl, value) < 0)
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panicf("Cannot write control '%s'", name);
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}
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}
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/* set a control, potentially supports several values */
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void alsa_controls_set(const char *name, snd_ctl_elem_type_t type,
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unsigned nr_values, long *val)
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{
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return alsa_controls_get_set(false, name, type, nr_values, val);
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}
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/* get a control, potentially supports several values */
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void alsa_controls_get(const char *name, snd_ctl_elem_type_t type,
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unsigned nr_values, long *val)
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{
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return alsa_controls_get_set(true, name, type, nr_values, val);
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}
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/* get control information */
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void alsa_controls_get_info(const char *name, int *out_count)
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{
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snd_ctl_elem_id_t *id;
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snd_ctl_elem_info_t *info;
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/* allocate things on stack to speedup */
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snd_ctl_elem_id_alloca(&id);
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snd_ctl_elem_info_alloca(&info);
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/* find control */
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if(!alsa_controls_find(id, name))
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panicf("Cannot find control '%s'", name);
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/* get info */
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snd_ctl_elem_info_set_id(info, id);
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if(snd_ctl_elem_info(alsa_ctl, info) < 0)
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panicf("Cannot get control '%s' info", name);
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*out_count = snd_ctl_elem_info_get_count(info);
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}
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/* helper function: set a control with a single boolean value */
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void alsa_controls_set_bool(const char *name, bool val)
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{
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long lval = val;
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alsa_controls_set(name, SND_CTL_ELEM_TYPE_BOOLEAN, 1, &lval);
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}
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/* helper function: set a control with a single enum value */
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void alsa_controls_set_enum(const char *name, const char *enum_name)
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{
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long idx = alsa_controls_find_enum(name, enum_name);
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if(idx < 0)
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panicf("Cannot find enum '%s' for control '%s'", enum_name, name);
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alsa_controls_set(name, SND_CTL_ELEM_TYPE_ENUMERATED, 1, &idx);
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}
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/* helper function: set a control with one or more integers */
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void alsa_controls_set_ints(const char *name, int count, long *val)
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{
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return alsa_controls_set(name, SND_CTL_ELEM_TYPE_INTEGER, count, val);
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}
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/* helper function: get a control with a single boolean value */
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bool alsa_controls_get_bool(const char *name)
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{
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long lval = 0;
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alsa_controls_get(name, SND_CTL_ELEM_TYPE_BOOLEAN, 1, &lval);
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return lval != 0;
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}
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