From 6ebefb4c8b523ecac35b7440907ef9e57d0154f0 Mon Sep 17 00:00:00 2001
From: David Robillard <d@drobilla.net>
Date: Fri, 23 May 2008 03:41:45 +0000
Subject: Merge improvemennts to MIDI stuff from Ardour.

git-svn-id: http://svn.drobilla.net/lad/raul@1227 a436a847-0d15-0410-975c-d299462d15a1
---
 raul/RingBuffer.hpp | 114 ++++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 89 insertions(+), 25 deletions(-)

(limited to 'raul/RingBuffer.hpp')

diff --git a/raul/RingBuffer.hpp b/raul/RingBuffer.hpp
index 4098a2f..dff1464 100644
--- a/raul/RingBuffer.hpp
+++ b/raul/RingBuffer.hpp
@@ -1,5 +1,5 @@
 /* This file is part of Raul.
- * Copyright (C) 2007 Dave Robillard <http://drobilla.net>
+ * Copyright (C) 2007-2008 Dave Robillard <http://drobilla.net>
  * 
  * Raul is free software; you can redistribute it and/or modify it under the
  * terms of the GNU General Public License as published by the Free Software
@@ -19,6 +19,7 @@
 #define RAUL_RING_BUFFER_HPP
 
 #include <cassert>
+#include <iostream>
 #include <glib.h>
 
 namespace Raul {
@@ -62,7 +63,7 @@ public:
 		
 		if (w > r) {
 			return ((r - w + _size) % _size) - 1;
-		} else if(w < r) {
+		} else if (w < r) {
 			return (r - w) - 1;
 		} else {
 			return _size - 1;
@@ -83,20 +84,65 @@ public:
 
 	size_t capacity() const { return _size; }
 
+	size_t peek(size_t size, T* dst);
+	bool   full_peek(size_t size, T* dst);
+
 	size_t read(size_t size, T* dst);
-	void   write(size_t size, const T* src);
-	
 	bool   full_read(size_t size, T* dst);
 
+	bool   skip(size_t size);
+	
+	void   write(size_t size, const T* src);
+
 protected:
-	mutable gint _write_ptr;
-	mutable gint _read_ptr;
+	mutable int _write_ptr;
+	mutable int _read_ptr;
 	
 	size_t _size; ///< Size (capacity) in bytes
-	T*  _buf;     ///< size, event, size, event...
+	T*     _buf;  ///< size, event, size, event...
 };
 
 
+/** Peek at the ringbuffer (read w/o advancing read pointer).
+ *
+ * Note that a full read may not be done if the data wraps around.
+ * Caller must check return value and call again if necessary, or use the 
+ * full_peek method which does this automatically.
+ */
+template<typename T>
+size_t
+RingBuffer<T>::peek(size_t size, T* dst)
+{
+	const size_t priv_read_ptr = g_atomic_int_get(&_read_ptr);
+
+	const size_t read_size = (priv_read_ptr + size < _size)
+			? size
+			: _size - priv_read_ptr;
+	
+	memcpy(dst, &_buf[priv_read_ptr], read_size);
+
+	return read_size;
+}
+
+
+template<typename T>
+bool
+RingBuffer<T>::full_peek(size_t size, T* dst)
+{
+	if (read_space() < size) {
+		return false;
+	}
+
+	const size_t read_size = peek(size, dst);
+	
+	if (read_size < size) {
+		peek(size - read_size, dst + read_size);
+	}
+
+	return true;
+}
+
+
 /** Read from the ringbuffer.
  *
  * Note that a full read may not be done if the data wraps around.
@@ -121,6 +167,40 @@ RingBuffer<T>::read(size_t size, T* dst)
 }
 
 
+template<typename T>
+bool
+RingBuffer<T>::full_read(size_t size, T* dst)
+{
+	if (read_space() < size) {
+		return false;
+	}
+
+	const size_t read_size = read(size, dst);
+	
+	if (read_size < size) {
+		read(size - read_size, dst + read_size);
+	}
+
+	return true;
+}
+
+
+template<typename T>
+bool
+RingBuffer<T>::skip(size_t size)
+{
+	if (read_space() < size) {
+		std::cerr << "WARNING: Attempt to skip past end of MIDI ring buffer" << std::endl;
+		return false;
+	}
+	
+	const size_t priv_read_ptr = g_atomic_int_get(&_read_ptr);
+	g_atomic_int_set(&_read_ptr, (priv_read_ptr + size) % _size);
+
+	return true;
+}
+
+
 template<typename T>
 inline void
 RingBuffer<T>::write(size_t size, const T* src)
@@ -129,33 +209,17 @@ RingBuffer<T>::write(size_t size, const T* src)
 	
 	if (priv_write_ptr + size <= _size) {
 		memcpy(&_buf[priv_write_ptr], src, size);
-        g_atomic_int_set(&_write_ptr, (priv_write_ptr + size) % _size);
+		g_atomic_int_set(&_write_ptr, (priv_write_ptr + size) % _size);
 	} else {
 		const size_t this_size = _size - priv_write_ptr;
 		assert(this_size < size);
 		assert(priv_write_ptr + this_size <= _size);
 		memcpy(&_buf[priv_write_ptr], src, this_size);
 		memcpy(&_buf[0], src+this_size, size - this_size);
-        g_atomic_int_set(&_write_ptr, size - this_size);
+		g_atomic_int_set(&_write_ptr, size - this_size);
 	}
 }
 
-
-template<typename T>
-bool
-RingBuffer<T>::full_read(size_t size, T* dst)
-{
-	if (read_space() < size)
-		return false;
-
-	const size_t read_size = read(size, dst);
-	
-	if (read_size < size)
-		read(size - read_size, dst + read_size);
-
-	return true;
-}
-
 	
 } // namespace Raul
 
-- 
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