libtgvoip/os/linux/AudioOutputALSA.cpp

//
// libtgvoip is free and unencumbered public domain software.
// For more information, see http://unlicense.org or the UNLICENSE file
// you should have received with this source code distribution.
//


#include <assert.h>
#include <dlfcn.h>
#include "AudioOutputALSA.h"
#include "../../logging.h"
#include "../../VoIPController.h"

#define BUFFER_SIZE 960
#define CHECK_ERROR(res, msg) if(res<0){LOGE(msg ": %s", _snd_strerror(res)); failed=true; return;}
#define CHECK_DL_ERROR(res, msg) if(!res){LOGE(msg ": %s", dlerror()); failed=true; return;}
#define LOAD_FUNCTION(lib, name, ref) {ref=(typeof(ref))dlsym(lib, name); CHECK_DL_ERROR(ref, "Error getting entry point for " name);}

using namespace tgvoip::audio;

AudioOutputALSA::AudioOutputALSA(std::string devID){
	isPlaying=false;
	handle=NULL;

	lib=dlopen("libasound.so.2", RTLD_LAZY);
	if(!lib)
		lib=dlopen("libasound.so", RTLD_LAZY);
	if(!lib){
		LOGE("Error loading libasound: %s", dlerror());
		failed=true;
		return;
	}

	LOAD_FUNCTION(lib, "snd_pcm_open", _snd_pcm_open);
	LOAD_FUNCTION(lib, "snd_pcm_set_params", _snd_pcm_set_params);
	LOAD_FUNCTION(lib, "snd_pcm_close", _snd_pcm_close);
	LOAD_FUNCTION(lib, "snd_pcm_writei", _snd_pcm_writei);
	LOAD_FUNCTION(lib, "snd_pcm_recover", _snd_pcm_recover);
	LOAD_FUNCTION(lib, "snd_strerror", _snd_strerror);

	SetCurrentDevice(devID);
}

AudioOutputALSA::~AudioOutputALSA(){
	if(handle)
		_snd_pcm_close(handle);
	if(lib)
		dlclose(lib);
}

void AudioOutputALSA::Start(){
	if(failed || isPlaying)
		return;

	isPlaying=true;
	thread=new Thread(new MethodPointer<AudioOutputALSA>(&AudioOutputALSA::RunThread, this), NULL);
	thread->SetName("AudioOutputALSA");
	thread->Start();
}

void AudioOutputALSA::Stop(){
	if(!isPlaying)
		return;

	isPlaying=false;
	thread->Join();
	delete thread;
	thread=NULL;
}

bool AudioOutputALSA::IsPlaying(){
	return isPlaying;
}
void AudioOutputALSA::RunThread(void* arg){
	unsigned char buffer[BUFFER_SIZE*2];
	snd_pcm_sframes_t frames;
	while(isPlaying){
		InvokeCallback(buffer, sizeof(buffer));
		frames=_snd_pcm_writei(handle, buffer, BUFFER_SIZE);
		if (frames < 0){
			frames = _snd_pcm_recover(handle, frames, 0);
		}
		if (frames < 0) {
			LOGE("snd_pcm_writei failed: %s\n", _snd_strerror(frames));
			break;
		}
	}
}

void AudioOutputALSA::SetCurrentDevice(std::string devID){
	bool wasPlaying=isPlaying;
	isPlaying=false;
	if(handle){
		thread->Join();
		_snd_pcm_close(handle);
	}
	currentDevice=devID;

	int res=_snd_pcm_open(&handle, devID.c_str(), SND_PCM_STREAM_PLAYBACK, 0);
	if(res<0)
		res=_snd_pcm_open(&handle, "default", SND_PCM_STREAM_PLAYBACK, 0);
	CHECK_ERROR(res, "snd_pcm_open failed");

	res=_snd_pcm_set_params(handle, SND_PCM_FORMAT_S16, SND_PCM_ACCESS_RW_INTERLEAVED, 1, 48000, 1, 100000);
	CHECK_ERROR(res, "snd_pcm_set_params failed");

	if(wasPlaying){
		isPlaying=true;
		thread->Start();
	}
}

void AudioOutputALSA::EnumerateDevices(std::vector<AudioOutputDevice>& devs){
	int (*_snd_device_name_hint)(int card, const char* iface, void*** hints);
	char* (*_snd_device_name_get_hint)(const void* hint, const char* id);
	int (*_snd_device_name_free_hint)(void** hinst);
	void* lib=dlopen("libasound.so.2", RTLD_LAZY);
	if(!lib)
		dlopen("libasound.so", RTLD_LAZY);
	if(!lib)
		return;

	_snd_device_name_hint=(typeof(_snd_device_name_hint))dlsym(lib, "snd_device_name_hint");
	_snd_device_name_get_hint=(typeof(_snd_device_name_get_hint))dlsym(lib, "snd_device_name_get_hint");
	_snd_device_name_free_hint=(typeof(_snd_device_name_free_hint))dlsym(lib, "snd_device_name_free_hint");

	if(!_snd_device_name_hint || !_snd_device_name_get_hint || !_snd_device_name_free_hint){
		dlclose(lib);
		return;
	}

	char** hints;
	int err=_snd_device_name_hint(-1, "pcm", (void***)&hints);
	if(err!=0){
		dlclose(lib);
		return;
	}

	char** n=hints;
	while(*n){
		char* name=_snd_device_name_get_hint(*n, "NAME");
		if(strncmp(name, "surround", 8)==0 || strcmp(name, "null")==0){
			free(name);
			n++;
			continue;
		}
		char* desc=_snd_device_name_get_hint(*n, "DESC");
		char* ioid=_snd_device_name_get_hint(*n, "IOID");
		if(!ioid || strcmp(ioid, "Output")==0){
			char* l1=strtok(desc, "\n");
			char* l2=strtok(NULL, "\n");
			char* tmp=strtok(l1, ",");
			char* actualName=tmp;
			while((tmp=strtok(NULL, ","))){
				actualName=tmp;
			}
			if(actualName[0]==' ')
				actualName++;
			AudioOutputDevice dev;
			dev.id=std::string(name);
			if(l2){
				char buf[256];
				snprintf(buf, sizeof(buf), "%s (%s)", actualName, l2);
				dev.displayName=std::string(buf);
			}else{
				dev.displayName=std::string(actualName);
			}
			devs.push_back(dev);
		}
		free(name);
		free(desc);
		free(ioid);
		n++;
	}

	dlclose(lib);
}