From 0b181dd995c58bde48e2e4d8d090de9387a5379d Mon Sep 17 00:00:00 2001
From: Tobias <neurocopter@gmail.com>
Date: Tue, 30 Jul 2013 17:56:33 +0200
Subject: [PATCH] AP_Buffer: remove header/source separation to allow arbitrary
 template parameters without explicit instantiation in the cpp file.

http://stackoverflow.com/questions/495021/why-can-templates-only-be-implemented-in-the-header-file
---
 libraries/AP_Buffer/AP_Buffer.cpp | 95 -------------------------------
 libraries/AP_Buffer/AP_Buffer.h   | 82 +++++++++++++++++++++++++-
 2 files changed, 81 insertions(+), 96 deletions(-)
 delete mode 100644 libraries/AP_Buffer/AP_Buffer.cpp

diff --git a/libraries/AP_Buffer/AP_Buffer.cpp b/libraries/AP_Buffer/AP_Buffer.cpp
deleted file mode 100644
index 7e65197654..0000000000
--- a/libraries/AP_Buffer/AP_Buffer.cpp
+++ /dev/null
@@ -1,95 +0,0 @@
-// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
-
-/// @file	AP_Buffer.h
-/// @brief	fifo buffer template class
-
-#include <AP_Buffer.h>
-#include <stdint.h>
-
-// Constructor
-template <class T, uint8_t SIZE>
-AP_Buffer<T,SIZE>::AP_Buffer() :
-	_num_items(0), _head(0)
-{
-}
-
-// clear - removes all points from the curve
-template <class T, uint8_t SIZE>
-void AP_Buffer<T,SIZE>::clear() {
-	// clear the curve
-	_num_items = 0;
-    _head = 0;
-}
-
-template <class T, uint8_t SIZE>
-void AP_Buffer<T,SIZE>::push_back( const T &item )
-{
-    // determine position of new item
-    uint8_t tail = _head + _num_items;
-    if( tail >= SIZE ) {
-        tail -= SIZE;
-    }
-
-    // add item to buffer
-    _buff[tail] = item;
-
-    // increment number of items
-    if( _num_items < SIZE ) {
-        _num_items++;
-    }else{
-        // no room for new items so drop oldest item
-        _head++;
-        if( _head >= SIZE ) {
-            _head = 0;
-        }
-    }
-}
-
-template <class T, uint8_t SIZE>
-T AP_Buffer<T,SIZE>::pop_front()
-{
-	T result;
-
-	// return zero if buffer is empty
-	if( _num_items == 0 ) {
-		return 0;
-	}
-
-	// get next value in buffer
-    result = _buff[_head];
-
-    // increment to next point
-    _head++;
-    if( _head >= SIZE )
-        _head = 0;
-
-    // reduce number of items
-    _num_items--;
-
-    // return item
-    return result;
-}
-
-template <class T, uint8_t SIZE>
-const T& AP_Buffer<T,SIZE>::peek(uint8_t position) const
-{
-    uint8_t j = _head + position;
-
-    // return zero if position is out of range
-    if( position >= _num_items ) {
-    	const static T r = 0;
-        return r;
-    }
-
-    // wrap around if necessary
-    if( j >= SIZE )
-        j -= SIZE;
-
-    // return desired value
-    return _buff[j];
-}
-
-// explicitly instantiate all needed template instances
-// (this is needed to allow the separation of declaration and definition into header and source files)
-template class AP_Buffer<float,  5>;
-template class AP_Buffer<float, 15>;
diff --git a/libraries/AP_Buffer/AP_Buffer.h b/libraries/AP_Buffer/AP_Buffer.h
index 393ba9f646..1cc52cc0ff 100644
--- a/libraries/AP_Buffer/AP_Buffer.h
+++ b/libraries/AP_Buffer/AP_Buffer.h
@@ -62,8 +62,88 @@ private:
 };
 
 // Typedef for convenience - add more as needed
-// (The used template instances have also to be instantiated explicitly in the source file.)
 typedef AP_Buffer<float,5> AP_BufferFloat_Size5;
 typedef AP_Buffer<float,15> AP_BufferFloat_Size15;
 
+template <class T, uint8_t SIZE>
+AP_Buffer<T,SIZE>::AP_Buffer() :
+	_num_items(0), _head(0)
+{
+}
+
+template <class T, uint8_t SIZE>
+void AP_Buffer<T,SIZE>::clear() {
+	// clear the curve
+	_num_items = 0;
+    _head = 0;
+}
+
+template <class T, uint8_t SIZE>
+void AP_Buffer<T,SIZE>::push_back( const T &item )
+{
+    // determine position of new item
+    uint8_t tail = _head + _num_items;
+    if( tail >= SIZE ) {
+        tail -= SIZE;
+    }
+
+    // add item to buffer
+    _buff[tail] = item;
+
+    // increment number of items
+    if( _num_items < SIZE ) {
+        _num_items++;
+    }else{
+        // no room for new items so drop oldest item
+        _head++;
+        if( _head >= SIZE ) {
+            _head = 0;
+        }
+    }
+}
+
+template <class T, uint8_t SIZE>
+T AP_Buffer<T,SIZE>::pop_front()
+{
+	T result;
+
+	// return zero if buffer is empty
+	if( _num_items == 0 ) {
+		return 0;
+	}
+
+	// get next value in buffer
+    result = _buff[_head];
+
+    // increment to next point
+    _head++;
+    if( _head >= SIZE )
+        _head = 0;
+
+    // reduce number of items
+    _num_items--;
+
+    // return item
+    return result;
+}
+
+template <class T, uint8_t SIZE>
+const T& AP_Buffer<T,SIZE>::peek(uint8_t position) const
+{
+    uint8_t j = _head + position;
+
+    // return zero if position is out of range
+    if( position >= _num_items ) {
+    	const static T r = 0;
+        return r;
+    }
+
+    // wrap around if necessary
+    if( j >= SIZE )
+        j -= SIZE;
+
+    // return desired value
+    return _buff[j];
+}
+
 #endif  // __AP_BUFFER_H__