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/*
* Copyright(C) 2018 "IoT.bzh"
* Author 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.
*
* reference :
* https://github.com/zonque/simple-alsa-loop/blob/master/loop.c
* https://www.alsa-project.org/alsa-doc/alsa-lib/_2test_2pcm_8c-example.html#a31
*
*/
#define _GNU_SOURCE // needed for vasprintf
#include "alsa-softmixer.h"
#include <pthread.h>
#include <sys/syscall.h>
typedef struct {
const char *uid;
long current;
long target;
int numid;
snd_ctl_t *ctlDev;
AlsaVolRampT *params;
sd_event_source *evtsrc;
CtlSourceT *source;
sd_event *sdLoop;
} VolRampHandleT;
STATIC int VolRampTimerCB(sd_event_source* source, uint64_t timer, void* handle) {
VolRampHandleT *rampHandle = (VolRampHandleT*) handle;
int error;
uint64_t usec;
// RampDown
if (rampHandle->current > rampHandle->target) {
rampHandle->current = rampHandle->current - rampHandle->params->stepDown;
if (rampHandle->current < rampHandle->target) rampHandle->current = rampHandle->target;
}
// RampUp
if (rampHandle->current < rampHandle->target) {
rampHandle->current = rampHandle->current + rampHandle->params->stepUp;
if (rampHandle->current > rampHandle->target) rampHandle->current = rampHandle->target;
}
error = AlsaCtlNumidSetLong(rampHandle->source, rampHandle->ctlDev, rampHandle->numid, rampHandle->current);
if (error) goto OnErrorExit;
// we reach target stop volram event
if (rampHandle->current == rampHandle->target) {
sd_event_source_unref(rampHandle->evtsrc);
snd_ctl_close (rampHandle->ctlDev);
free (rampHandle);
}
else {
// otherwise validate timer for a new run
sd_event_now(rampHandle->sdLoop, CLOCK_MONOTONIC, &usec);
sd_event_source_set_enabled(rampHandle->evtsrc, SD_EVENT_ONESHOT);
error = sd_event_source_set_time(rampHandle->evtsrc, usec + rampHandle->params->delay);
}
return 0;
OnErrorExit:
AFB_ApiWarning(rampHandle->source->api, "VolRampTimerCB stream=%s numid=%d value=%ld", rampHandle->uid, rampHandle->numid, rampHandle->current);
sd_event_source_unref(source); // abandon volRamp
return -1;
}
PUBLIC int AlsaVolRampApply(CtlSourceT *source, AlsaSndLoopT *frontend, AlsaLoopStreamT *stream, AlsaVolRampT *ramp, json_object *volumeJ) {
long curvol, newvol;
const char*volString;
int error;
uint64_t usec;
snd_ctl_t *ctlDev =AlsaCtlOpenCtl(source, frontend->cardid);
if (!ctlDev) goto OnErrorExit;
error = AlsaCtlNumidGetLong(source, ctlDev, stream->volume, &curvol);
if (error) {
AFB_ApiError(source->api,"AlsaVolRampApply:%s(stream) Fail to get volume numid=%d", stream->uid, stream->volume);
goto OnErrorExit;
}
switch (json_object_get_type(volumeJ)) {
case json_type_string:
volString = json_object_get_string(volumeJ);
switch (volString[0]) {
case '+':
sscanf(&volString[1], "%ld", &newvol);
newvol = curvol + newvol;
break;
case '-':
sscanf(&volString[1], "%ld", &newvol);
newvol = curvol - newvol;
break;
default:
AFB_ApiError(source->api,"AlsaVolRampApply:%s(stream) relative volume should start by '+|-' value=%s", stream->uid, json_object_get_string(volumeJ));
goto OnErrorExit;
}
break;
case json_type_int:
newvol = json_object_get_int(volumeJ);
break;
default:
AFB_ApiError(source->api,"AlsaVolRampApply:%s(stream) volume should be string or integer value=%s", stream->uid, json_object_get_string(volumeJ));
goto OnErrorExit;
}
VolRampHandleT *rampHandle = calloc(1, sizeof (VolRampHandleT));
rampHandle->uid= stream->uid;
rampHandle->numid= stream->volume;
rampHandle->ctlDev= ctlDev;
rampHandle->source = source;
rampHandle->params = ramp;
rampHandle->target = newvol;
rampHandle->current= curvol;
rampHandle->sdLoop= stream->copy.sdLoop;
// set a timer with ~250us accuracy
sd_event_now(rampHandle->sdLoop, CLOCK_MONOTONIC, &usec);
(void)sd_event_add_time(rampHandle->sdLoop, &rampHandle->evtsrc, CLOCK_MONOTONIC, usec+100, 250, VolRampTimerCB, rampHandle);
return 0;
OnErrorExit:
return -1;
}
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