Ryujinx/Ryujinx.Audio.Renderer/Common/NodeStates.cs

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//
// Copyright (c) 2019-2020 Ryujinx
//
// This program 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.
//
// This program 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 this program. If not, see <https://www.gnu.org/licenses/>.
//
using Ryujinx.Audio.Renderer.Utils;
using System;
using System.Diagnostics;
namespace Ryujinx.Audio.Renderer.Common
{
public class NodeStates
{
private class Stack
{
private Memory<int> _storage;
private int _index;
private int _nodeCount;
public void Reset(Memory<int> storage, int nodeCount)
{
Debug.Assert(storage.Length * sizeof(int) >= CalcBufferSize(nodeCount));
_storage = storage;
_index = 0;
_nodeCount = nodeCount;
}
public int GetCurrentCount()
{
return _index;
}
public void Push(int data)
{
Debug.Assert(_index + 1 <= _nodeCount);
_storage.Span[_index++] = data;
}
public int Pop()
{
Debug.Assert(_index > 0);
return _storage.Span[--_index];
}
public int Top()
{
return _storage.Span[_index - 1];
}
public static int CalcBufferSize(int nodeCount)
{
return nodeCount * sizeof(int);
}
}
private int _nodeCount;
private EdgeMatrix _discovered;
private EdgeMatrix _finished;
private Memory<int> _resultArray;
private Stack _stack;
private int _tsortResultIndex;
private enum NodeState : byte
{
Unknown,
Discovered,
Finished
}
public NodeStates()
{
_stack = new Stack();
_discovered = new EdgeMatrix();
_finished = new EdgeMatrix();
}
public static int GetWorkBufferSize(int nodeCount)
{
return Stack.CalcBufferSize(nodeCount * nodeCount) + 0xC * nodeCount + 2 * EdgeMatrix.GetWorkBufferSize(nodeCount);
}
public void Initialize(Memory<byte> nodeStatesWorkBuffer, int nodeCount)
{
int workBufferSize = GetWorkBufferSize(nodeCount);
Debug.Assert(nodeStatesWorkBuffer.Length >= workBufferSize);
_nodeCount = nodeCount;
int edgeMatrixWorkBufferSize = EdgeMatrix.GetWorkBufferSize(nodeCount);
_discovered.Initialize(nodeStatesWorkBuffer.Slice(0, edgeMatrixWorkBufferSize), nodeCount);
_finished.Initialize(nodeStatesWorkBuffer.Slice(edgeMatrixWorkBufferSize, edgeMatrixWorkBufferSize), nodeCount);
nodeStatesWorkBuffer = nodeStatesWorkBuffer.Slice(edgeMatrixWorkBufferSize * 2);
_resultArray = SpanMemoryManager<int>.Cast(nodeStatesWorkBuffer.Slice(0, sizeof(int) * nodeCount));
nodeStatesWorkBuffer = nodeStatesWorkBuffer.Slice(sizeof(int) * nodeCount);
Memory<int> stackWorkBuffer = SpanMemoryManager<int>.Cast(nodeStatesWorkBuffer.Slice(0, Stack.CalcBufferSize(nodeCount * nodeCount)));
_stack.Reset(stackWorkBuffer, nodeCount * nodeCount);
}
private void Reset()
{
_discovered.Reset();
_finished.Reset();
_tsortResultIndex = 0;
_resultArray.Span.Fill(-1);
}
private NodeState GetState(int index)
{
Debug.Assert(index < _nodeCount);
if (_discovered.Test(index))
{
Debug.Assert(!_finished.Test(index));
return NodeState.Discovered;
}
else if (_finished.Test(index))
{
Debug.Assert(!_discovered.Test(index));
return NodeState.Finished;
}
return NodeState.Unknown;
}
private void SetState(int index, NodeState state)
{
switch (state)
{
case NodeState.Unknown:
_discovered.Reset(index);
_finished.Reset(index);
break;
case NodeState.Discovered:
_discovered.Set(index);
_finished.Reset(index);
break;
case NodeState.Finished:
_finished.Set(index);
_discovered.Reset(index);
break;
}
}
private void PushTsortResult(int index)
{
Debug.Assert(index < _nodeCount);
_resultArray.Span[_tsortResultIndex++] = index;
}
public ReadOnlySpan<int> GetTsortResult()
{
return _resultArray.Span.Slice(0, _tsortResultIndex);
}
public bool Sort(EdgeMatrix edgeMatrix)
{
Reset();
if (_nodeCount <= 0)
{
return true;
}
for (int i = 0; i < _nodeCount; i++)
{
if (GetState(i) == NodeState.Unknown)
{
_stack.Push(i);
}
while (_stack.GetCurrentCount() > 0)
{
int topIndex = _stack.Top();
NodeState topState = GetState(topIndex);
if (topState == NodeState.Discovered)
{
SetState(topIndex, NodeState.Finished);
PushTsortResult(topIndex);
_stack.Pop();
}
else if (topState == NodeState.Finished)
{
_stack.Pop();
}
else
{
if (topState == NodeState.Unknown)
{
SetState(topIndex, NodeState.Discovered);
}
for (int j = 0; j < edgeMatrix.GetNodeCount(); j++)
{
if (edgeMatrix.Connected(topIndex, j))
{
NodeState jState = GetState(j);
if (jState == NodeState.Unknown)
{
_stack.Push(j);
}
// Found a loop, reset and propagate rejection.
else if (jState == NodeState.Discovered)
{
Reset();
return false;
}
}
}
}
}
}
return true;
}
}
}