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/*
* AlsaUseCase -- provide low level interface with ALSA lib (extracted from alsa-json-gateway code)
* Copyright (C) 2015,2016,2017, Fulup Ar Foll fulup@iot.bzh
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#define _GNU_SOURCE // needed for vasprintf
#include <alsa/asoundlib.h>
#include <systemd/sd-event.h>
#include "Alsa-ApiHat.h"
STATIC int addOneSndCtl(afb_req request, snd_ctl_t *ctlDev, json_object *ctlJ) {
int err;
json_object *jName, *jNumid, *jTmp;
const char *ctlName;
int ctlNumid, ctlMax, ctlMin, ctlStep, ctlCount, ctlSubDev;
snd_ctl_elem_type_t ctlType;
snd_ctl_elem_info_t *elemInfo;
// parse json ctl object
json_object_object_get_ex (ctlJ, "name" , &jName);
json_object_object_get_ex (ctlJ, "numid", &jNumid);
if (!jName || !jNumid) {
afb_req_fail_f (request, "ctl-invalid", "crl=%s name/numid missing", json_object_to_json_string(ctlJ));
goto OnErrorExit;
}
ctlName = json_object_to_json_string(jName);
ctlNumid = json_object_get_int(jNumid);
// default for json_object_get_int is zero
json_object_object_get_ex (ctlJ, "min" , &jTmp);
ctlMin = json_object_get_int(jTmp);
json_object_object_get_ex (ctlJ, "max" , &jTmp);
if (!jTmp) ctlMax=1;
else ctlMax = json_object_get_int(jTmp);
json_object_object_get_ex (ctlJ, "step" , &jTmp);
if (!jTmp) ctlStep=1;
else ctlStep = json_object_get_int(jTmp);
json_object_object_get_ex (ctlJ, "count" , &jTmp);
if (!jTmp) ctlCount=2;
else ctlCount = json_object_get_int(jTmp);
json_object_object_get_ex (ctlJ, "subdev" , &jTmp);
ctlSubDev = json_object_get_int(jTmp);
json_object_object_get_ex (ctlJ, "type" , &jTmp);
if (!jTmp) ctlType=SND_CTL_ELEM_TYPE_INTEGER;
else ctlType = json_object_get_int(jTmp);
// set info event ID and get value
snd_ctl_elem_info_alloca(&elemInfo);
snd_ctl_elem_info_set_name (elemInfo, ctlName); // map ctlInfo to ctlId elemInfo is updated !!!
snd_ctl_elem_info_set_numid(elemInfo, ctlNumid); // map ctlInfo to ctlId elemInfo is updated !!!
if (snd_ctl_elem_info(ctlDev, elemInfo) >= 0) {
afb_req_fail_f (request, "ctl-already-exist", "crl=%s name/numid not unique", json_object_to_json_string(ctlJ));
goto OnErrorExit;
}
snd_ctl_elem_info_set_subdevice(elemInfo, ctlSubDev);
switch (ctlType) {
case SND_CTL_ELEM_TYPE_BOOLEAN:
err = snd_ctl_add_boolean_elem_set(ctlDev, elemInfo, 1, ctlCount);
if (err) {
afb_req_fail_f (request, "ctl-invalid-bool", "crl=%s invalid boolean data", json_object_to_json_string(ctlJ));
goto OnErrorExit;
}
break;
case SND_CTL_ELEM_TYPE_INTEGER:
break;
case SND_CTL_ELEM_TYPE_INTEGER64:
break;
case SND_CTL_ELEM_TYPE_ENUMERATED:
break;
case SND_CTL_ELEM_TYPE_BYTES:
break;
default:
afb_req_fail_f (request, "ctl-invalid-type", "crl=%s invalid/unknown type", json_object_to_json_string(ctlJ));
goto OnErrorExit;
}
return 0;
OnErrorExit:
return -1;
}
PUBLIC void alsaAddCustomCtls(afb_req request) {
int err;
json_object *ctlsJ;
enum json_type;
snd_ctl_t *ctlDev=NULL;
const char *devid;
devid = afb_req_value(request, "devid");
if (devid == NULL) {
afb_req_fail_f (request, "devid-missing", "devid MUST be defined for alsaAddCustomCtls");
goto OnErrorExit;
}
// open control interface for devid
err = snd_ctl_open(&ctlDev, devid, SND_CTL_READONLY);
if (err < 0) {
afb_req_fail_f (request, "devid-unknown", "SndCard devid=[%s] Not Found err=%s", devid, snd_strerror(err));
goto OnErrorExit;
}
// extract sound controls and parse json
ctlsJ = json_tokener_parse (afb_req_value(request, "ctls"));
if (!ctlsJ) {
afb_req_fail_f (request, "ctls-missing", "ctls MUST be defined as a JSON array for alsaAddCustomCtls");
goto OnErrorExit;
}
switch (json_object_get_type(ctlsJ)) {
case json_type_object:
addOneSndCtl(request, ctlDev, ctlsJ);
break;
case json_type_array:
for (int idx= 1; idx < json_object_array_length (ctlsJ); idx++) {
json_object *ctlJ = json_object_array_get_idx (ctlsJ, idx);
addOneSndCtl(request, ctlDev, ctlJ) ;
}
break;
default:
afb_req_fail_f (request, "ctls-invalid","ctls=%s not valid JSON array", json_object_to_json_string(ctlsJ));
goto OnErrorExit;
}
OnErrorExit:
if (ctlDev) snd_ctl_close(ctlDev);
return;
}
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