From 22cdfccb11679d6ae241653c9cb92c32f4fc1fde Mon Sep 17 00:00:00 2001
From: Roland Reichwein <mail@reichwein.it>
Date: Fri, 3 Jan 2025 21:02:11 +0100
Subject: Integrate ClickStream into PCM

---
 PCM.h | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 52 insertions(+), 8 deletions(-)

(limited to 'PCM.h')

diff --git a/PCM.h b/PCM.h
index bfa1e24..3e9b41d 100644
--- a/PCM.h
+++ b/PCM.h
@@ -1,22 +1,29 @@
 #pragma once
 
-#include "ClickStream.h"
-
 #include "config.h"
+#include "log.h"
+
+#include <libreichwein/file.h>
 
 #include <alsa/asoundlib.h>
 #include <fmt/format.h>
 
 #include <iostream>
 #include <string>
+#include <vector>
 
 using namespace std::string_literals;
 
 class PCM
 {
 public:
-  PCM(ClickStream& stream): m_stream(stream)
+  PCM(): m_phase(1000000)
   {
+    // prepare the sample
+    std::string data_s = Reichwein::File::getFile("media/click.s16le");
+    m_data.resize(data_s.size() / 2); // src is in bytes
+    memcpy(m_data.data(), data_s.data(), data_s.size());
+
     // non-blocking
     if ((err = snd_pcm_open(&handle, device, SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK)) < 0) {
       throw std::runtime_error(fmt::format("Playback open error: {}", snd_strerror(err)));
@@ -27,11 +34,11 @@ public:
                                   1,
                                   f_sample,
                                   1,
-                                  100000)) < 0) {   // latency in us
+                                  pcm_latency_us)) < 0) {   // latency in us
       throw std::runtime_error(fmt::format("Playback open error: {}", snd_strerror(err)));
     }
 
-    m_stream.generate();
+    generate();
 
     npfd = snd_pcm_poll_descriptors_count(handle);
     if (npfd < 0) {
@@ -69,6 +76,33 @@ public:
     free(pfd);
   }
 
+  void click()
+  {
+    snd_pcm_sframes_t delay;
+    if (0 > snd_pcm_delay(handle, &delay)) {
+    }
+
+    m_phase = 0; // - click_latency_frames + delay
+  }
+
+  // generate 1 buffer size
+  void generate()
+  {
+    int i;
+
+    for (i = 0; i < nframes; i++) {
+      if (m_phase < 0 || m_phase >= m_data.size())
+      {
+        buffer[i] = 0;
+      }
+      else
+      {
+        buffer[i] = m_data[m_phase];
+      }
+      m_phase++;
+    }
+  }
+
   int fd()
   {
     return pfd->fd;
@@ -77,7 +111,7 @@ public:
   // write from buffer to ALSA PCM
   void write()
   {
-    snd_pcm_sframes_t written = snd_pcm_writei(handle, m_stream.get_buffer(), nframes);
+    snd_pcm_sframes_t written = snd_pcm_writei(handle, buffer, nframes);
     if (written < 0) {
         if (written == -EPIPE) {
           std::cout << "Warning: PCM underrun" << std::endl;
@@ -93,7 +127,15 @@ public:
       std::cout << "Warning: written " << std::to_string(written) << " frames instead of "<< std::to_string(nframes) << std::endl;
     }
 
-    m_stream.generate();
+    snd_pcm_sframes_t avail;
+    snd_pcm_sframes_t delay;
+    if (0 > snd_pcm_avail_delay(handle, &avail, &delay)) {
+      log_cout << "Error detecting avail and delay" << std::endl;
+    } else {
+      log_cout << fmt::format("Delay: {}, avail. buffer; {} frames", delay, avail) << std::endl;
+    }
+
+    generate();
   }
 
   bool wait_for_event()
@@ -130,6 +172,8 @@ private:
   int npfd;
   struct pollfd* pfd;
 
-  ClickStream& m_stream;
+  std::vector<uint16_t> m_data;
+  int32_t m_phase;
+  int16_t buffer[nframes];
 };
 
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