From 413ef5a3b466e0e0678112041d2db840388b26a2 Mon Sep 17 00:00:00 2001
From: Peter Barker <pbarker@barker.dropbear.id.au>
Date: Fri, 26 Oct 2018 13:31:20 +1100
Subject: [PATCH] AC_Avoid: add singleton

---
 libraries/AC_Avoidance/AC_Avoid.cpp | 14 ++++++++++++++
 libraries/AC_Avoidance/AC_Avoid.h   | 11 +++++++++++
 2 files changed, 25 insertions(+)

diff --git a/libraries/AC_Avoidance/AC_Avoid.cpp b/libraries/AC_Avoidance/AC_Avoid.cpp
index 58446411e7..42233a47d8 100644
--- a/libraries/AC_Avoidance/AC_Avoid.cpp
+++ b/libraries/AC_Avoidance/AC_Avoid.cpp
@@ -57,6 +57,8 @@ AC_Avoid::AC_Avoid(const AP_AHRS& ahrs, const AC_Fence& fence, const AP_Proximit
       _proximity(proximity),
       _beacon(beacon)
 {
+    _singleton = this;
+
     AP_Param::setup_object_defaults(this, var_info);
 }
 
@@ -571,3 +573,15 @@ void AC_Avoid::get_proximity_roll_pitch_pct(float &roll_positive, float &roll_ne
         }
     }
 }
+
+// singleton instance
+AC_Avoid *AC_Avoid::_singleton;
+
+namespace AP {
+
+AC_Avoid *ac_avoid()
+{
+    return AC_Avoid::get_singleton();
+}
+
+}
diff --git a/libraries/AC_Avoidance/AC_Avoid.h b/libraries/AC_Avoidance/AC_Avoid.h
index 55ec0e3d9d..1469ca67a9 100644
--- a/libraries/AC_Avoidance/AC_Avoid.h
+++ b/libraries/AC_Avoidance/AC_Avoid.h
@@ -34,6 +34,11 @@ public:
     AC_Avoid(const AC_Avoid &other) = delete;
     AC_Avoid &operator=(const AC_Avoid&) = delete;
 
+    // get singleton instance
+    static AC_Avoid *get_singleton() {
+        return _singleton;
+    }
+
     /*
      * Adjusts the desired velocity so that the vehicle can stop
      * before the fence/object.
@@ -140,4 +145,10 @@ private:
     AP_Int8 _behavior;          // avoidance behaviour (slide or stop)
 
     bool _proximity_enabled = true; // true if proximity sensor based avoidance is enabled (used to allow pilot to enable/disable)
+
+    static AC_Avoid *_singleton;
+};
+
+namespace AP {
+    AC_Avoid *ac_avoid();
 };