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authorChristian Glöckner <cgloeckner@freenet.de>2016-01-21 18:00:28 +0100
committerAndré Nusser <andre.nusser@googlemail.com>2016-02-09 09:02:18 +0100
commit6253e37c2f0219d61193d0d405e7f23a4bae3287 (patch)
tree28f687ca1327cec4cac848a80eb82cd8128ded27 /drumgizmo/output/alsa.cc
parent3ab30fd4168217894ee781cf93df522d3565cec8 (diff)
Added AlsaOutputEngine
Diffstat (limited to 'drumgizmo/output/alsa.cc')
-rw-r--r--drumgizmo/output/alsa.cc141
1 files changed, 141 insertions, 0 deletions
diff --git a/drumgizmo/output/alsa.cc b/drumgizmo/output/alsa.cc
new file mode 100644
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+++ b/drumgizmo/output/alsa.cc
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+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/***************************************************************************
+ * alsa.cc
+ *
+ * Do 21. Jan 16:48:32 CET 2016
+ * Copyright 2016 Christian Glöckner
+ * cgloeckner@freenet.de
+ ****************************************************************************/
+
+/*
+ * This file is part of DrumGizmo.
+ *
+ * DrumGizmo 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.
+ *
+ * DrumGizmo 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 DrumGizmo; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+#include "alsa.h"
+
+int const BUFFER_SIZE = 40960;
+
+struct AlsaInitError {
+ int const code;
+ std::string const msg;
+
+ AlsaInitError(int op_code, std::string const & msg)
+ : code{code}
+ , msg{msg} {
+ }
+
+ static inline void test(int code, std::string const & msg) {
+ if (code < 0) {
+ throw AlsaInitError(code, msg);
+ }
+ }
+};
+
+AlsaOutputEngine::AlsaOutputEngine()
+ : handle{nullptr}
+ , params{nullptr}
+ , data{}
+ , num_channels{0u}
+ , dev{"default"}
+ , srate{44100}
+ , frames{32} {
+}
+
+AlsaOutputEngine::~AlsaOutputEngine() {
+ if (params) {
+ // snd_pcm_hw_params_alloca uses std alloc
+ free(params);
+ }
+ if (handle != nullptr) {
+ snd_pcm_close(handle);
+ }
+}
+
+bool AlsaOutputEngine::init(Channels channels) {
+ // try to initialize alsa
+ try {
+ int value = snd_pcm_open(&handle, dev.c_str(), SND_PCM_STREAM_PLAYBACK, 0);
+ AlsaInitError::test(value, "snd_pcm_open");
+ num_channels = channels.size();
+ if (handle == nullptr) {
+ printf("No handle!\n");
+ return false;
+ }
+ // Allocate and init a hardware parameters object
+ snd_pcm_hw_params_alloca(&params);
+ value = snd_pcm_hw_params_any(handle, params);
+ AlsaInitError::test(value, "snd_pcm_hw_params_any");
+
+ value = snd_pcm_hw_params_set_access(handle, params, SND_PCM_ACCESS_RW_INTERLEAVED);
+ AlsaInitError::test(value, "snd_pcm_hw_params_set_access");
+ value = snd_pcm_hw_params_set_format(handle, params, SND_PCM_FORMAT_FLOAT);
+ AlsaInitError::test(value, "snd_pcm_hw_params_set_format");
+ value = snd_pcm_hw_params_set_channels(handle, params, num_channels);
+ AlsaInitError::test(value, "snd_pcm_hw_params_set_channels");
+ value = snd_pcm_hw_params_set_rate_near(handle, params, &srate, 0);
+ AlsaInitError::test(value, "snd_pcm_hw_params_set_rate_near");
+ value = snd_pcm_hw_params_set_period_size_near(handle, params, &frames, 0);
+ AlsaInitError::test(value, "snd_pcm_hw_params_set_period_size_near");
+ value = snd_pcm_hw_params(handle, params);
+ AlsaInitError::test(value, "snd_pcm_hw_params");
+
+ } catch (AlsaInitError const & error) {
+ printf("%s failed: %s\n", error.msg.c_str(), snd_strerror(error.code));
+ fflush(stdout);
+ return false;
+ }
+
+ data.clear();
+ data.resize(BUFFER_SIZE * num_channels);
+
+ return true;
+}
+
+void AlsaOutputEngine::setParm(std::string parm, std::string value) {
+ if (parm == "dev") {
+ dev = value;
+ } else if (parm == "frames") {
+ frames = std::stoi(value);
+ } else if (parm == "srate") {
+ srate = std::stoi(value);
+ }
+}
+
+bool AlsaOutputEngine::start() {
+ return true;
+}
+
+void AlsaOutputEngine::stop() {
+}
+
+void AlsaOutputEngine::pre(size_t nsamples) {
+}
+
+void AlsaOutputEngine::run(int ch, sample_t* samples, size_t nsamples) {
+ // Write channel data in interleaved buffer
+ for (auto i = 0u; i < nsamples; ++i) {
+ data[i * num_channels + ch] = samples[i];
+ }
+}
+
+void AlsaOutputEngine::post(size_t nsamples) {
+ // Write the interleaved buffer to the soundcard
+ snd_pcm_writei(handle, data.data(), nsamples);
+}
+
+size_t AlsaOutputEngine::samplerate() {
+ return srate;
+}