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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
*
* Copyright (C) 2016 Amaury Pouly
*
* 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 software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "alsa-controls.h"
#include "panic.h"
#include "debug.h"
#include <stdlib.h>
/* alsa control handle, we keep it open at all times */
static snd_ctl_t *alsa_ctl;
/* list of all controls, we allocate and fill it once, so we can easily lookup */
static snd_ctl_elem_list_t *alsa_ctl_list;
static unsigned alsa_ctl_count;
/* for each control, we store some info to avoid constantly using ALSA's horrible lookup functions */
static struct ctl_t
{
snd_ctl_elem_id_t *id; /* ID associated with the control */
const char *name; /* name of the control */
snd_ctl_elem_type_t type; /* control type (boolean, enum, ...) */
unsigned count; /* dimension of the control */
unsigned items; /* number of items (for enums) */
const char **enum_name; /* names of the enum, indexed by ALSA index */
} *alsa_ctl_info;
#if defined(DEBUG)
static const char *alsa_ctl_type_name(snd_ctl_elem_type_t type)
{
switch(type)
{
case SND_CTL_ELEM_TYPE_BOOLEAN: return "BOOLEAN";
case SND_CTL_ELEM_TYPE_INTEGER: return "INTEGER";
case SND_CTL_ELEM_TYPE_ENUMERATED: return "ENUMERATED";
default: return "???";
}
}
#endif
void alsa_controls_init(const char *name)
{
/* allocate list on heap because it is used it is used in other functions */
snd_ctl_elem_list_malloc(&alsa_ctl_list);
/* there is only one card and "default" always works */
if(snd_ctl_open(&alsa_ctl, name, 0) < 0)
panicf("Cannot open ctl\n");
/* ALSA is braindead: first "get" the list -> only retrieve count */
if(snd_ctl_elem_list(alsa_ctl, alsa_ctl_list) < 0)
panicf("Cannot get element list\n");
/* now we can allocate the list since the know the size */
alsa_ctl_count = snd_ctl_elem_list_get_count(alsa_ctl_list);
if(snd_ctl_elem_list_alloc_space(alsa_ctl_list, alsa_ctl_count) < 0)
panicf("Cannot allocate space for element list\n");
/* ... and get the list again! */
if(snd_ctl_elem_list(alsa_ctl, alsa_ctl_list) < 0)
panicf("Cannot get element list\n");
/* now cache the info */
alsa_ctl_info = malloc(sizeof(struct ctl_t) * alsa_ctl_count);
snd_ctl_elem_info_t *info;
snd_ctl_elem_info_malloc(&info);
for(unsigned i = 0; i < alsa_ctl_count; i++)
{
/* allocate the ID and retrieve it */
snd_ctl_elem_id_malloc(&alsa_ctl_info[i].id);
snd_ctl_elem_list_get_id(alsa_ctl_list, i, alsa_ctl_info[i].id);
/* NOTE: name is valid as long as the ID lives; since we keep both, no need to copy */
alsa_ctl_info[i].name = snd_ctl_elem_id_get_name(alsa_ctl_info[i].id);
/* get info */
snd_ctl_elem_info_set_id(info, alsa_ctl_info[i].id);
if(snd_ctl_elem_info(alsa_ctl, info) < 0)
panicf("Cannot get control '%s' info", alsa_ctl_info[i].name);
alsa_ctl_info[i].type = snd_ctl_elem_info_get_type(info);
alsa_ctl_info[i].count = snd_ctl_elem_info_get_count(info);
if(alsa_ctl_info[i].type == SND_CTL_ELEM_TYPE_ENUMERATED)
{
alsa_ctl_info[i].items = snd_ctl_elem_info_get_items(info);
alsa_ctl_info[i].enum_name = malloc(sizeof(char *) * alsa_ctl_info[i].items);
for(unsigned j = 0; j < alsa_ctl_info[i].items; j++)
{
snd_ctl_elem_info_set_item(info, j);
if(snd_ctl_elem_info(alsa_ctl, info) < 0)
panicf("Cannot get control '%s' info for item %u", alsa_ctl_info[i].name, j);
/* NOTE: copy string because it becomes invalid after info is freed */
alsa_ctl_info[i].enum_name[j] = strdup(snd_ctl_elem_info_get_item_name(info));
}
}
else
alsa_ctl_info[i].items = 0;
}
snd_ctl_elem_info_free(info);
DEBUGF("ALSA controls:\n");
for(unsigned i = 0; i < alsa_ctl_count; i++)
{
DEBUGF("- name='%s', type=%s, count=%u\n", alsa_ctl_info[i].name,
alsa_ctl_type_name(alsa_ctl_info[i].type), alsa_ctl_info[i].count);
if(alsa_ctl_info[i].type == SND_CTL_ELEM_TYPE_ENUMERATED)
{
DEBUGF(" items:");
for(unsigned j = 0; j < alsa_ctl_info[i].items; j++)
{
if(j != 0)
DEBUGF(",");
DEBUGF(" '%s'", alsa_ctl_info[i].enum_name[j]);
}
DEBUGF("\n");
}
}
}
void alsa_controls_close(void)
{
snd_ctl_close(alsa_ctl);
}
/* find a control element ID by name, return -1 of not found or index into array */
int alsa_controls_find(const char *name)
{
/* enumerate controls */
for(unsigned i = 0; i < alsa_ctl_count; i++)
if(strcmp(alsa_ctl_info[i].name, name) == 0)
return i;
/* not found */
return -1;
}
bool alsa_has_control(const char *name)
{
return alsa_controls_find(name) >= 0;
}
/* find a control element enum index by name, return -1 if not found */
int alsa_controls_find_enum(const char *name, const char *enum_name)
{
/* find control */
int idx = alsa_controls_find(name);
if(idx < 0)
panicf("Cannot find control '%s'", name);
/* list items */
for(unsigned i = 0; i < alsa_ctl_info[idx].items; i++)
{
if(strcmp(alsa_ctl_info[idx].enum_name[i], enum_name) == 0)
return i;
}
return -1;
}
/* set/get a control, potentially supports several values */
void alsa_controls_get_set(bool get, const char *name, snd_ctl_elem_type_t type,
unsigned nr_values, long *val)
{
snd_ctl_elem_value_t *value;
/* allocate things on stack to speedup */
snd_ctl_elem_value_alloca(&value);
/* find control */
int idx = alsa_controls_find(name);
if(idx < 0)
panicf("Cannot find control '%s'", name);
/* check the type of the control */
if(alsa_ctl_info[idx].type != type)
panicf("Control '%s' has wrong type (got %d, expected %d", name,
alsa_ctl_info[idx].type, type);
if(alsa_ctl_info[idx].count != nr_values)
panicf("Control '%s' has wrong count (got %u, expected %u)",
name, alsa_ctl_info[idx].count, nr_values);
snd_ctl_elem_value_set_id(value, alsa_ctl_info[idx].id);
/* set value */
if(get)
{
/* read value */
if(snd_ctl_elem_read(alsa_ctl, value) < 0)
panicf("Cannot read control '%s'", name);
for(unsigned i = 0; i < nr_values; i++)
{
/* ALSA is braindead: there are "typed" setters but they all take long anyway */
if(type == SND_CTL_ELEM_TYPE_BOOLEAN)
val[i] = snd_ctl_elem_value_get_boolean(value, i);
else if(type == SND_CTL_ELEM_TYPE_INTEGER)
val[i] = snd_ctl_elem_value_get_integer(value, i);
else if(type == SND_CTL_ELEM_TYPE_ENUMERATED)
val[i] = snd_ctl_elem_value_get_enumerated(value, i);
}
}
else
{
for(unsigned i = 0; i < nr_values; i++)
{
/* ALSA is braindead: there are "typed" setters but they all take long anyway */
if(type == SND_CTL_ELEM_TYPE_BOOLEAN)
snd_ctl_elem_value_set_boolean(value, i, val[i]);
else if(type == SND_CTL_ELEM_TYPE_INTEGER)
snd_ctl_elem_value_set_integer(value, i, val[i]);
else if(type == SND_CTL_ELEM_TYPE_ENUMERATED)
snd_ctl_elem_value_set_enumerated(value, i, val[i]);
}
/* write value */
if(snd_ctl_elem_write(alsa_ctl, value) < 0)
panicf("Cannot write control '%s'", name);
}
}
/* set a control, potentially supports several values */
void alsa_controls_set(const char *name, snd_ctl_elem_type_t type,
unsigned nr_values, long *val)
{
return alsa_controls_get_set(false, name, type, nr_values, val);
}
/* get a control, potentially supports several values */
void alsa_controls_get(const char *name, snd_ctl_elem_type_t type,
unsigned nr_values, long *val)
{
return alsa_controls_get_set(true, name, type, nr_values, val);
}
/* get control information */
void alsa_controls_get_info(const char *name, int *out_count)
{
/* find control */
int idx = alsa_controls_find(name);
if(idx < 0)
panicf("Cannot find control '%s'", name);
/* get info */
*out_count = alsa_ctl_info[idx].count;
}
/* helper function: set a control with a single boolean value */
void alsa_controls_set_bool(const char *name, bool val)
{
long lval = val;
alsa_controls_set(name, SND_CTL_ELEM_TYPE_BOOLEAN, 1, &lval);
}
/* helper function: set a control with a single enum value */
void alsa_controls_set_enum(const char *name, const char *enum_name)
{
long idx = alsa_controls_find_enum(name, enum_name);
if(idx < 0)
panicf("Cannot find enum '%s' for control '%s'", enum_name, name);
alsa_controls_set(name, SND_CTL_ELEM_TYPE_ENUMERATED, 1, &idx);
}
/* helper function: set a control with one or more integers */
void alsa_controls_set_ints(const char *name, int count, long *val)
{
return alsa_controls_set(name, SND_CTL_ELEM_TYPE_INTEGER, count, val);
}
/* helper function: get a control with a single boolean value */
bool alsa_controls_get_bool(const char *name)
{
long lval = 0;
alsa_controls_get(name, SND_CTL_ELEM_TYPE_BOOLEAN, 1, &lval);
return lval != 0;
}
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