Work in Progress

1 files changed, 180 insertions, 0 deletions

diff --git a/ALSA-afb/Alsa-AddCtl.c b/ALSA-afb/Alsa-AddCtl.c
new file mode 100644
index 0000000..e30ebea
--- /dev/null
+++ b/ALSA-afb/Alsa-AddCtl.c
@@ -0,0 +1,180 @@
+/*
+ * 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;
+}
+