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less buffer churn for rewind management. should help performance a tiny bit.

This commit is contained in:
zeromus 2013-07-27 23:02:26 +00:00
parent faa307bb6e
commit c0e2a2bbb7
1 changed files with 65 additions and 43 deletions
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108
BizHawk.MultiClient/Rewind.cs
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@ -85,17 +85,20 @@ namespace BizHawk.MultiClient
}
/// <summary>
/// The push and pop semantics are for historical reasons and not resemblence
/// The push and pop semantics are for historical reasons and not resemblence to normal definitions
/// </summary>
public void PushMemoryStream(MemoryStream ms)
public void Push(ArraySegment<byte> seg)
{
var buf = ms.GetBuffer();
int len = (int)ms.Length;
var buf = seg.Array;
int len = seg.Count;
long offset = Enqueue(0, len);
mStream.Position = offset;
mStream.Write(buf, 0, len);
mStream.Write(buf, seg.Offset, len);
}
/// <summary>
/// The push and pop semantics are for historical reasons and not resemblence to normal definitions
/// </summary>
public MemoryStream PopMemoryStream()
{
var item = Pop();
@ -289,58 +292,77 @@ namespace BizHawk.MultiClient
// Builds a delta for states that are <= 64K in size.
void CaptureRewindState64K() { CaptureRewindStateDelta(true); }
byte[] TempBuf = new byte[0];
void CaptureRewindStateDelta(bool isSmall)
{
byte[] CurrentState = Global.Emulator.SaveStateBinary();
int beginChangeSequence = -1;
bool inChangeSequence = false;
var ms = new MemoryStream();
var writer = new BinaryWriter(ms);
if (CurrentState.Length != LastState.Length)
MemoryStream ms;
//try to set up the buffer in advance so we dont ever have exceptions in here
if(TempBuf.Length < CurrentState.Length)
TempBuf = new byte[CurrentState.Length*2];
ms = new MemoryStream(TempBuf, 0, TempBuf.Length, true, true);
RETRY:
try
{
writer.Write(true); // full state
writer.Write(LastState);
}
else
{
writer.Write(false); // delta state
for (int i = 0; i < CurrentState.Length; i++)
var writer = new BinaryWriter(ms);
if (CurrentState.Length != LastState.Length)
{
if (inChangeSequence == false)
writer.Write(true); // full state
writer.Write(LastState);
}
else
{
writer.Write(false); // delta state
for (int i = 0; i < CurrentState.Length; i++)
{
if (i >= LastState.Length)
if (inChangeSequence == false)
{
if (i >= LastState.Length)
continue;
if (CurrentState[i] == LastState[i])
continue;
inChangeSequence = true;
beginChangeSequence = i;
continue;
}
if (i - beginChangeSequence == 254 || i == CurrentState.Length - 1)
{
writer.Write((byte)(i - beginChangeSequence + 1));
if (isSmall) writer.Write((ushort)beginChangeSequence);
else writer.Write(beginChangeSequence);
writer.Write(LastState, beginChangeSequence, i - beginChangeSequence + 1);
inChangeSequence = false;
continue;
}
if (CurrentState[i] == LastState[i])
continue;
inChangeSequence = true;
beginChangeSequence = i;
continue;
}
if (i - beginChangeSequence == 254 || i == CurrentState.Length - 1)
{
writer.Write((byte)(i - beginChangeSequence + 1));
if(isSmall) writer.Write((ushort)beginChangeSequence);
else writer.Write(beginChangeSequence);
writer.Write(LastState, beginChangeSequence, i - beginChangeSequence + 1);
inChangeSequence = false;
continue;
}
if (CurrentState[i] == LastState[i])
{
writer.Write((byte)(i - beginChangeSequence));
if(isSmall) writer.Write((ushort)beginChangeSequence);
else writer.Write(beginChangeSequence);
writer.Write(LastState, beginChangeSequence, i - beginChangeSequence);
inChangeSequence = false;
{
writer.Write((byte)(i - beginChangeSequence));
if (isSmall) writer.Write((ushort)beginChangeSequence);
else writer.Write(beginChangeSequence);
writer.Write(LastState, beginChangeSequence, i - beginChangeSequence);
inChangeSequence = false;
}
}
}
}
catch (NotSupportedException)
{
//ok... we had an exception after all
//if we did actually run out of room in the memorystream, then try it again with a bigger buffer
TempBuf = new byte[TempBuf.Length * 2];
goto RETRY;
}
LastState = CurrentState;
ms.Position = 0;
RewindBuf.PushMemoryStream(ms);
var seg = new ArraySegment<byte>(TempBuf, 0, (int)ms.Position);
RewindBuf.Push(seg);
}
void RewindLarge() { RewindDelta(false); }