From fb992677cf62b6aa982476538faae43e5bbbd87f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9=20Nusser?= <andre.nusser@googlemail.com>
Date: Sun, 12 Jan 2020 15:41:39 +0100
Subject: Introduce EventsDS to handle all the events and enable new features.

Also:
* Added an id.h class to make IDs with type
* Added a range class to easily use range based for loops
---
 src/memory_heap.h | 113 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 113 insertions(+)
 create mode 100644 src/memory_heap.h

(limited to 'src/memory_heap.h')

diff --git a/src/memory_heap.h b/src/memory_heap.h
new file mode 100644
index 0000000..e2901b8
--- /dev/null
+++ b/src/memory_heap.h
@@ -0,0 +1,113 @@
+/* -*- Mode: c++ -*- */
+/***************************************************************************
+ *            memory_heap.h
+ *
+ *  Sun Jan 19 13:49:56 CET 2020
+ *  Copyright 2020 André Nusser
+ *  andre.nusser@googlemail.com
+ ****************************************************************************/
+
+/*
+ *  This file is part of DrumGizmo.
+ *
+ *  DrumGizmo is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU Lesser General Public License as published by
+ *  the Free Software Foundation; either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  DrumGizmo is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public License
+ *  along with DrumGizmo; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
+ */
+#pragma once
+
+#include <vector>
+
+// The purpose of this class is to have a heap for objects of a certain type.
+// We want to avoid using the general "new"/"delete" memory allocation as this
+// is problematic for real-time as well as slow. The underlying container still
+// is a vector to handle the case when for some reason we need more memory
+// than initially anticipated. Instead of throwing errors and giving up, we can
+// then at least allocate new memory and just hope for the best.
+template <typename T>
+class MemoryHeap
+{
+public:
+	using Index = std::size_t;
+	using Indices = std::vector<Index>;
+
+	MemoryHeap() = default;
+	MemoryHeap(std::size_t size)
+	{
+		memory.reserve(size);
+		free_indices.reserve(size);
+	}
+
+	template <typename... Args>
+	Index emplace(Args&&... args);
+
+	Index add(T const& element);
+	T& get(Index index);
+	T const& get(Index index) const;
+	void remove(Index index);
+
+private:
+	std::vector<T> memory;
+	Indices free_indices;
+};
+
+template <typename T>
+auto MemoryHeap<T>::add(T const& element) -> Index
+{
+	if (free_indices.empty())
+	{
+		memory.push_back(element);
+		return memory.size()-1;
+	}
+
+	auto free_index = free_indices.back();
+	free_indices.pop_back();
+	memory[free_index] = element;
+	return free_index;
+}
+
+template <typename T>
+template <typename... Args>
+auto MemoryHeap<T>::emplace(Args&&... args) -> Index
+{
+	if (free_indices.empty())
+	{
+		memory.emplace_back(std::forward<Args>(args)...);
+		return memory.size()-1;
+	}
+
+	auto free_index = free_indices.back();
+	free_indices.pop_back();
+	memory[free_index] = T(std::forward<Args>(args)...);
+	return free_index;
+}
+
+template <typename T>
+T& MemoryHeap<T>::get(Index index)
+{
+	assert(index < memory.size());
+	return memory[index];
+}
+
+template <typename T>
+T const& MemoryHeap<T>::get(Index index) const
+{
+	assert(index < memory.size());
+	return memory[index];
+}
+
+template <typename T>
+void MemoryHeap<T>::remove(Index index)
+{
+	free_indices.push_back(index);
+}
-- 
cgit v1.2.3