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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(struct afb_req request, snd_ctl_t *ctlDev, json_object *ctlJ) {
snd_ctl_elem_info_t *cinfo;
int err;
int i;
unsigned int def_val;
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, cinfo, 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;
}
snd_ctl_elem_write(ctlDev, &ctlElem);
return 0;
OnErrorExit:
return -1;
}
// Subscribe to every Alsa CtlEvent send by a given board
PUBLIC void alsaAddCustomCtl (struct afb_req request) {
snd_ctl_t *ctlDev;
int err;
const char *devid, *ctls;
json_object *ctlsJ;
devid = afb_req_value(request, "devid");
if (!devid) {
afb_req_fail_f (request, "missing-devid", "devid=xxx missing");
goto OnErrorExit;
}
// open control interface for devid
err = snd_ctl_open(&ctlDev, devid, 0);
if (err < 0) {
ctlDev=NULL;
afb_req_fail_f (request, "devid-unknown", "SndCard devid=%s Not Found err=%s", queryValues.devid, snd_strerror(err));
goto OnErrorExit;
}
ctls = afb_req_value(request, "ctls");
if (!ctls) {
afb_req_fail_f (request, "missing-ctls", "ctls=[{name:xxx, numdid=xx, ...}] missing");
goto OnErrorExit;
}
ctlsJ = json_tokener_parse(ctls);
if (!ctlsJ) {
afb_req_fail_f (request, "ctls-notjson","ctls=%s not a valid json entry", ctls);
goto OnErrorExit;
};
enum json_type jtype= json_object_get_type(ctlsJ);
switch (jtype) {
int error;
json_object *ctlJ;
case json_type_array:
int count = json_object_array_length (ctlsJ);
for (int idx=0; idx < count; idx ++) {
ctlJ = json_object_array_get_idx (ctlsJ, idx);
error = alsaAddCtrl (request, ctlDev, ctlsJ);
if (error) goto OnErrorExit;
}
break;
case json_type_object:
error = alsaAddCtrl (request, ctlDev, ctlsJ);
if (error) goto OnErrorExit;
break;
default:
afb_req_fail_f (request, "ctls-notarray","ctls=%s not valid JSON control object", ctls);
goto OnErrorExit;
}
snd_ctl_close(ctlDev);
return;
OnErrorExit:
if (ctlDev) snd_ctl_close(ctlDev);
return;
}
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