Add an audio queue implementation

2 files changed, 133 insertions, 0 deletions

diff --git a/src/device_mixer.cpp b/src/device_mixer.cpp
index 09a640a..1529c78 100644
--- a/src/device_mixer.cpp
+++ b/src/device_mixer.cpp
@@ -311,4 +311,87 @@ namespace audiere {
     m_last_r = new_r;
   }
 
+  AudioQueue::AudioQueue(int blockSize, int queueLen)
+  {
+    m_block_size = blockSize;
+    m_max_queue_len = queueLen;
+    m_shutdown = false;
+
+    for (int i = 0; i < queueLen + 1; i++) {
+      char* buf = new char[blockSize];
+
+      m_buffer_list.push_back(AudioBuffer(buf, blockSize));
+      m_free_list.push_back(&m_buffer_list.back());
+    }
+  }
+
+  AudioQueue::~AudioQueue()
+  {
+    shutdown();
+    m_mutex.lock();
+    m_mutex.unlock();
+
+    while (!m_buffer_list.empty()) {
+      delete [] m_buffer_list.front().m_buf;
+      m_buffer_list.pop_front();
+    }
+  }
+
+  AudioBuffer* AudioQueue::get_buffer()
+  {
+    SYNCHRONIZED(m_buffer_mutex);
+    if (m_free_list.empty())
+      return 0;
+
+    AudioBuffer* buf = m_free_list.front();
+    m_free_list.pop_front();
+    return buf;
+  }
+
+  void  AudioQueue::put_buffer(AudioBuffer* buffer)
+  {
+    SYNCHRONIZED(m_buffer_mutex);
+    m_free_list.push_back(buffer);
+  }
+
+  bool  AudioQueue::push(AudioBuffer* buffer)
+  {
+    SYNCHRONIZED(m_mutex);
+
+    if (m_shutdown)
+      return false;
+
+    while (m_queue.size() >= size_t(m_max_queue_len)) {
+      m_cond.wait(m_mutex, 10);
+      if (m_shutdown)
+        return false;
+    }
+
+    m_queue.push_back(buffer);
+    return true;
+  }
+
+  AudioBuffer*  AudioQueue::pop()
+  {
+    SYNCHRONIZED(m_mutex);
+
+    if (m_shutdown || m_queue.empty())
+      return 0;
+
+    bool donotify = m_queue.size() >= size_t(m_max_queue_len);
+
+    AudioBuffer* buf = m_queue.front();
+    m_queue.pop_front();
+    if (donotify)
+      m_cond.notify();
+    return buf;
+  }
+
+  void  AudioQueue::shutdown()
+  {
+    SYNCHRONIZED(m_mutex);
+
+    m_shutdown = true;
+    m_cond.notify();
+  }
 }
diff --git a/src/device_mixer.h b/src/device_mixer.h
index 8ddd674..eb2ece0 100644
--- a/src/device_mixer.h
+++ b/src/device_mixer.h
@@ -89,6 +89,56 @@ namespace audiere {
     friend class MixerDevice;
   };
 
+  class AudioBuffer {
+  public:
+    AudioBuffer()
+      : m_buf(0), m_size(0) {
+    }
+
+    AudioBuffer(char* buf, int size)
+      : m_buf(buf), m_size(size) {
+    }
+
+    AudioBuffer(const AudioBuffer& o)
+      : m_buf(o.m_buf), m_size(o.m_size) {
+    }
+
+    char* m_buf;
+    int m_size;
+  };
+
+  class AudioQueue {
+  private:
+    AudioQueue();
+    AudioQueue(const AudioQueue&);
+
+  public:
+    AudioQueue(int blockSize, int queueLen);
+    ~AudioQueue();
+
+    AudioBuffer* get_buffer();
+    void put_buffer(AudioBuffer* buffer);
+
+    bool push(AudioBuffer* buffer);
+    AudioBuffer* pop();
+
+    void shutdown();
+
+  private:
+    CondVar m_cond;
+    Mutex m_mutex;
+    std::list<AudioBuffer*> m_queue;
+
+    Mutex m_buffer_mutex;
+    std::list<AudioBuffer> m_buffer_list;
+    std::list<AudioBuffer*> m_free_list;
+
+    int m_block_size;
+    int m_max_queue_len;
+
+    bool m_shutdown;
+  };
+
 }
 
 #endif