Use signals

1 files changed, 25 insertions, 21 deletions

diff --git a/alsa.cpp b/alsa.cpp
index 2eb5662..e669593 100644
--- a/alsa.cpp
+++ b/alsa.cpp
@@ -14,15 +14,18 @@
 #include <sys/time.h>
 #include <time.h>
 
-using namespace std::string_literals;
+#include <boost/signals2.hpp>
 
-//static const int CLICK_NOTE = 37;
-//static const int CLICK_CHANNEL = 4;
+using namespace std::string_literals;
 
+// Config
+static const int CLICK_NOTE = 37;
+static const int CLICK_CHANNEL = 4;
 static const char *device = "default";    // playback device
 const snd_pcm_sframes_t nframes = 1024;   // ~1/44th sec buffer size
 int16_t buffer[nframes];
 const unsigned int f_sample = 44100;
+
 const double pi = std::acos(-1);
 
 double diff_timespec(const struct timespec *time1, const struct timespec *time0) {
@@ -40,6 +43,7 @@ public:
     memcpy(m_data.data(), data_s.data(), data_s.size());
   }
 
+  // generate 1 buffer size
   void generate()
   {
     int i;
@@ -73,7 +77,7 @@ private:
 class PCM
 {
 public:
-  PCM()
+  PCM(ClickStream& stream): m_stream(stream)
   {
     // non-blocking
     if ((err = snd_pcm_open(&handle, device, SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK)) < 0) {
@@ -91,6 +95,8 @@ public:
         exit(EXIT_FAILURE);
     }
 
+    m_stream.generate();
+
     npfd = snd_pcm_poll_descriptors_count(handle);
     if (npfd < 0) {
       throw std::runtime_error("snd_pcm_poll_descriptors_count() failed");
@@ -148,6 +154,8 @@ public:
         if (written != nframes) {
           std::cout << "Warning: written " << std::to_string(written) << " frames instead of "<< std::to_string(nframes) << std::endl;
         }
+
+        m_stream.generate();
   }
 
   bool wait_for_event()
@@ -183,6 +191,8 @@ private:
 
   int npfd;
   struct pollfd* pfd;
+
+  ClickStream& m_stream;
 };
 
 class MIDI
@@ -253,6 +263,8 @@ public:
     free(pfd);
   }
 
+  boost::signals2::signal<void()> signal_click;
+
   int fd()
   {
     return pfd->fd;
@@ -291,10 +303,8 @@ public:
   }
 
   // returns if click starts
-  bool process(const snd_seq_event_t *ev)
+  void process(const snd_seq_event_t *ev)
   {
-     bool result = false;
-
      if((ev->type == SND_SEQ_EVENT_NOTEON)
             ||(ev->type == SND_SEQ_EVENT_NOTEOFF)) {
         const char *type = (ev->type == SND_SEQ_EVENT_NOTEON) ? "on " : "off";
@@ -304,9 +314,9 @@ public:
                                                ev->data.note.velocity,
                                                ev->data.control.channel);
         if (ev->type == SND_SEQ_EVENT_NOTEON) {
-//          if (ev->data.note.note == CLICK_NOTE && ev->data.control.channel == CLICK_CHANNEL) {
-            result = true;
-//          }
+          if (true || (ev->data.note.note == CLICK_NOTE && ev->data.control.channel == CLICK_CHANNEL)) {
+            signal_click();
+          }
         }
      }
      else if(ev->type == SND_SEQ_EVENT_CONTROLLER)
@@ -323,7 +333,6 @@ public:
      {
         printf("[%d] Unknown:  Unhandled Event Received\n", ev->time.tick);
      }
-     return result;
   }
 
   void wait_for_event()
@@ -352,15 +361,14 @@ int main(void)
   try {
     MIDI midi;
     ClickStream stream;
-    PCM pcm;
+    PCM pcm{stream};
 
-    stream.generate();
     pcm.write();
-    stream.generate();
+
+    midi.signal_click.connect([&](){stream.click();});
 
     while (true) {
-      //midi.wait_for_event();
-      //pcm.wait_for_event();
+      //std::cout << "Main loop entered." << std::endl;
       fd_set read_set;
       FD_ZERO(&read_set);
       FD_SET(midi.fd(), &read_set);
@@ -385,16 +393,12 @@ int main(void)
         //std::cout << "read..." << std::endl;
         auto event = midi.read();
         //std::cout << "process..." << std::endl;
-        if (midi.process(event)) {
-          stream.click();
-          //std::cout << "DEBUG: CLICK" << std::endl;
-        }
+        midi.process(event);
       }
 
       if (pcm.write_available()) {
         //std::cout << "DEBUG: WRITE" << std::endl;
         pcm.write();
-        stream.generate();
       }
     }
   } catch (const std::exception& ex) {