Ryujinx/Ryujinx.Horizon/HeapAllocator.cs

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using Ryujinx.Common;
using System;
using System.Collections.Generic;
using System.Diagnostics;
namespace Ryujinx.Horizon
{
class HeapAllocator
{
private const ulong InvalidAddress = ulong.MaxValue;
private struct Range : IComparable<Range>
{
public ulong Offset { get; }
public ulong Size { get; }
public Range(ulong offset, ulong size)
{
Offset = offset;
Size = size;
}
public int CompareTo(Range other)
{
return Offset.CompareTo(other.Offset);
}
}
private readonly List<Range> _freeRanges;
private ulong _currentHeapSize;
public HeapAllocator()
{
_freeRanges = new List<Range>();
_currentHeapSize = 0;
}
public ulong Allocate(ulong size, ulong alignment = 1UL)
{
ulong address = AllocateImpl(size, alignment);
if (address == InvalidAddress)
{
ExpandHeap(size + alignment - 1UL);
address = AllocateImpl(size, alignment);
Debug.Assert(address != InvalidAddress);
}
return address;
}
private void ExpandHeap(ulong expansionSize)
{
ulong oldHeapSize = _currentHeapSize;
ulong newHeapSize = BitUtils.AlignUp(oldHeapSize + expansionSize, 0x200000UL);
_currentHeapSize = newHeapSize;
HorizonStatic.Syscall.SetHeapSize(out ulong heapAddress, newHeapSize).AbortOnFailure();
Free(heapAddress + oldHeapSize, newHeapSize - oldHeapSize);
}
private ulong AllocateImpl(ulong size, ulong alignment)
{
for (int i = 0; i < _freeRanges.Count; i++)
{
var range = _freeRanges[i];
ulong alignedOffset = BitUtils.AlignUp(range.Offset, alignment);
ulong sizeDelta = alignedOffset - range.Offset;
ulong usableSize = range.Size - sizeDelta;
if (sizeDelta < range.Size && usableSize >= size)
{
_freeRanges.RemoveAt(i);
if (sizeDelta != 0)
{
InsertFreeRange(range.Offset, sizeDelta);
}
ulong endOffset = range.Offset + range.Size;
ulong remainingSize = endOffset - (alignedOffset + size);
if (remainingSize != 0)
{
InsertFreeRange(endOffset - remainingSize, remainingSize);
}
return alignedOffset;
}
}
return InvalidAddress;
}
public void Free(ulong offset, ulong size)
{
InsertFreeRangeComingled(offset, size);
}
private void InsertFreeRange(ulong offset, ulong size)
{
var range = new Range(offset, size);
int index = _freeRanges.BinarySearch(range);
if (index < 0)
{
index = ~index;
}
_freeRanges.Insert(index, range);
}
private void InsertFreeRangeComingled(ulong offset, ulong size)
{
ulong endOffset = offset + size;
var range = new Range(offset, size);
int index = _freeRanges.BinarySearch(range);
if (index < 0)
{
index = ~index;
}
if (index < _freeRanges.Count && _freeRanges[index].Offset == endOffset)
{
endOffset = _freeRanges[index].Offset + _freeRanges[index].Size;
_freeRanges.RemoveAt(index);
}
if (index > 0 && _freeRanges[index - 1].Offset + _freeRanges[index - 1].Size == offset)
{
offset = _freeRanges[index - 1].Offset;
_freeRanges.RemoveAt(--index);
}
range = new Range(offset, endOffset - offset);
_freeRanges.Insert(index, range);
}
}
}