From 445db2035f75570a6f215d9189ca4f447fb3f0ea Mon Sep 17 00:00:00 2001
From: Stefan Sayer <stefan.sayer@googlemail.com>
Date: Wed, 28 Mar 2007 02:09:28 +0000
Subject: [PATCH]  AmAudioFrontList AmAudio device, useful for e.g. fancier
 conferencing services

git-svn-id: http://svn.berlios.de/svnroot/repos/sems/trunk@285 8eb893ce-cfd4-0310-b710-fb5ebe64c474
---
 core/AmAdvancedAudio.cpp | 54 ++++++++++++++++++++++++++++++++++++++++
 core/AmAdvancedAudio.h   | 28 ++++++++++++++++++++-
 2 files changed, 81 insertions(+), 1 deletion(-)

diff --git a/core/AmAdvancedAudio.cpp b/core/AmAdvancedAudio.cpp
index a9e5dda9..7cc87983 100644
--- a/core/AmAdvancedAudio.cpp
+++ b/core/AmAdvancedAudio.cpp
@@ -226,3 +226,57 @@ int AmAudioDelay::read(unsigned int user_ts, unsigned int size) {
   sarr.read((unsigned int) (user_ts  - delay*8000.0), (short*)  ((unsigned char*) samples), size >> 1); 
   return size;
 }
+
+AmAudioFrontlist::AmAudioFrontlist(AmEventQueue* q) 
+  : AmPlaylist(q), back_audio(NULL)
+{
+}
+
+AmAudioFrontlist::AmAudioFrontlist(AmEventQueue* q, AmAudio* back_audio) 
+  : AmPlaylist(q), back_audio(back_audio)
+{
+}
+
+AmAudioFrontlist::~AmAudioFrontlist() {
+//   ba_mut.lock();
+//   if (back_audio)
+//     back_audio->close();
+//   ba_mut.unlock();
+}
+
+void AmAudioFrontlist::setBackAudio(AmAudio* new_ba) {
+  ba_mut.lock();
+  back_audio = new_ba;
+  ba_mut.unlock();
+}
+
+int AmAudioFrontlist::put(unsigned int user_ts, unsigned char* buffer, unsigned int size) {
+  // stay consistent with Playlist - if empty return size
+  int res = size; 
+  ba_mut.lock();
+
+  if (isEmpty()) {
+    if (back_audio) 
+      res = back_audio->put(user_ts, buffer, size);
+  } else {
+    res = AmPlaylist::put(user_ts, buffer, size);
+  }
+
+  ba_mut.unlock();
+  return res;
+}
+
+int AmAudioFrontlist::get(unsigned int user_ts, unsigned char* buffer, unsigned int size) {
+  // stay consistent with Playlist - if empty return size
+  int res = size; 
+
+  ba_mut.lock();
+  if (isEmpty()) {
+    if (back_audio) 
+      res = back_audio->get(user_ts, buffer, size);
+  } else {
+    res = AmPlaylist::get(user_ts, buffer, size);
+  }
+  ba_mut.unlock();
+  return res;
+}
diff --git a/core/AmAdvancedAudio.h b/core/AmAdvancedAudio.h
index baaedee7..78768736 100644
--- a/core/AmAdvancedAudio.h
+++ b/core/AmAdvancedAudio.h
@@ -29,6 +29,8 @@
 #define _AmAdvancedAudio_h_
 
 #include "AmAudio.h"
+#include "AmPlaylist.h"
+
 #include "AmThread.h"
 #include "amci/codecs.h"
 
@@ -84,6 +86,31 @@ class AmAudioQueue : public AmAudio {
   int read(unsigned int user_ts, unsigned int size);
 };
 
+/**
+ * AmAudioFrontlist is an AmAudio device, that has a playlist
+ * in front of a AmAudio entry, the 'back' device. The back device
+ * is only used if the playlist is empty. - This can be useful when 
+ * for example announcements should be played to the participant 
+ * while in a conference.
+ *
+ */
+class AmAudioFrontlist : public AmPlaylist {
+  AmMutex ba_mut;
+  AmAudio* back_audio;
+ public:
+
+  AmAudioFrontlist(AmEventQueue* q);
+  AmAudioFrontlist(AmEventQueue* q, AmAudio* back_audio);
+  ~AmAudioFrontlist();
+
+  void setBackAudio(AmAudio* new_ba);
+
+ protected:
+  int put(unsigned int user_ts, unsigned char* buffer, unsigned int size);
+  int get(unsigned int user_ts, unsigned char* buffer, unsigned int size);
+};
+
+
 /**
  * \brief \ref AmAudio that directly connects input and output
  *
@@ -111,7 +138,6 @@ class AmAudioDelay : public AmAudio {
   AmAudioDelay(float delay_sec);
   ~AmAudioDelay();
  protected:
-
   int write(unsigned int user_ts, unsigned int size);
   int read(unsigned int user_ts, unsigned int size);
 };