add first code bits of new alsa encoder

1 files changed, 90 insertions, 0 deletions

diff --git a/src/AlsaInput.h b/src/AlsaInput.h
new file mode 100644
index 0000000..b43ad7d
--- /dev/null
+++ b/src/AlsaInput.h
@@ -0,0 +1,90 @@
+/* ------------------------------------------------------------------
+ * Copyright (C) 2011 Martin Storsjo
+ * Copyright (C) 2013,2014 Matthias P. Braendli
+ *
+ * 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.
+ * -------------------------------------------------------------------
+ */
+
+#ifndef __ALSA_H_
+#define __ALSA_H_
+#include <cstdio>
+#include <stdint.h>
+#include <string>
+
+#include <alsa/asoundlib.h>
+#include <boost/thread/thread.hpp>
+
+#include "SampleQueue.h"
+
+using namespace std;
+
+// 16 bits per sample is fine for now
+#define BYTES_PER_SAMPLE 2
+
+// How many samples we insert into the queue each call
+#define NUM_SAMPLES_PER_CALL 10 // 10 samples @ 32kHz = 3.125ms
+
+class AlsaInput
+{
+    public:
+        AlsaInput(const string& alsa_dev,
+                unsigned int channels,
+                unsigned int rate,
+                SampleQueue<uint8_t>& queue) :
+            m_running(false),
+            m_alsa_dev(alsa_dev),
+            m_channels(channels),
+            m_rate(rate),
+            m_queue(queue),
+            m_alsa_handle(NULL) { }
+
+        ~AlsaInput()
+        {
+            if (m_running) {
+                m_running = false;
+                m_thread.interrupt();
+                m_thread.join();
+            }
+
+            if (m_alsa_handle) {
+                snd_pcm_abort(m_alsa_handle);
+                m_alsa_handle = NULL;
+            }
+        }
+
+        int prepare();
+
+        int start();
+
+    private:
+        AlsaInput(const AlsaInput& other) : m_queue(other.m_queue) {}
+
+        size_t read(uint8_t* buf, snd_pcm_uframes_t length);
+        void process();
+
+        bool m_running;
+        boost::thread m_thread;
+        string m_alsa_dev;
+        unsigned int m_channels;
+        unsigned int m_rate;
+
+        SampleQueue<uint8_t>& m_queue;
+
+        snd_pcm_t *m_alsa_handle;
+
+};
+
+#endif
+