SettingsDlgALSA.cpp

/*
 *   Copyright (c) 2019-2021 by Thomas A. Early N7TAE
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <iostream>
#include <alsa/asoundlib.h>

#include "SettingsDlg.h"

void CSettingsDlg::AudioRescanButton()
{
	auto inchoice = pAudioInputChoice->value();
	if (inchoice < 0)
		inchoice = 0;
	auto outchoice = pAudioOutputChoice->value();
	if (outchoice < 0)
		outchoice = 0;
	void **hints;
	if (snd_device_name_hint(-1, "pcm", &hints) < 0)
		return;
	void **n = hints;
	pAudioInputChoice->clear();
	pAudioOutputChoice->clear();
	AudioInMap.clear();
	AudioOutMap.clear();
	while (*n != NULL) {
		char *name = snd_device_name_get_hint(*n, "NAME");
		if (NULL == name) {
			n++;
			continue;
		}
		char *desc = snd_device_name_get_hint(*n, "DESC");
		if (NULL == desc) {
			free(name);
			n++;
			continue;
		}
		if ((0==strcmp(name, "default") || strstr(name, "plughw")) && NULL==strstr(desc, "without any conversions")) {

			char *io = snd_device_name_get_hint(*n, "IOID");
			bool is_input = true, is_output = true;

			if (io) {	// io == NULL means it's for both input and output
				if (0 == strcasecmp(io, "Input")) {
					is_output = false;
				} else if (0 == strcasecmp(io, "Output")) {
					is_input = false;
				} else {
					std::cerr << "ERROR: unexpected IOID=" << io << std::endl;
				}
				free(io);
			}

			std::string short_name(name);
			auto pos = short_name.find("plughw:CARD=");
			if (short_name.npos != pos) {
				short_name = short_name.replace(pos, 12, "");
				pos = short_name.find(",DEV=0");
				if (short_name.npos != pos)
					short_name = short_name.replace(pos, 6, "");
				if (0 == short_name.size())
					short_name.assign(name);
			}
			if (is_input) {
				snd_pcm_t *handle;
				if (snd_pcm_open(&handle, name, SND_PCM_STREAM_CAPTURE, 0) == 0) {
					AudioInMap[short_name] = std::pair<std::string, std::string>(name, desc);
					snd_pcm_close(handle);
					pAudioInputChoice->add(short_name.c_str());
				}
			}

			if (is_output) {
				snd_pcm_t *handle;
				if (snd_pcm_open(&handle, name, SND_PCM_STREAM_PLAYBACK, 0) == 0) {
					AudioOutMap[short_name] = std::pair<std::string, std::string>(name, desc);
					snd_pcm_close(handle);
					pAudioOutputChoice->add(short_name.c_str());
				}
			}

		}

	    if (name) {
	      	free(name);
		}
		if (desc) {
			free(desc);
		}
		n++;
	}
	snd_device_name_free_hint(hints);
	pAudioInputChoice->value(inchoice);
	AudioInputChoice();
	pAudioOutputChoice->value(outchoice);
	AudioOutputChoice();
}