private void RewindDelta(bool isSmall)
{
var ms = _rewindBuffer.PopMemoryStream();
var reader = new BinaryReader(ms);
var fullstate = reader.ReadBoolean();
if (fullstate)
{
Global.Emulator.LoadStateBinary(reader);
}
else
{
var output = new MemoryStream(_lastState);
while (ms.Position < ms.Length)
{
var len = reader.ReadByte();
int offset = isSmall ? reader.ReadUInt16() : reader.ReadInt32();
output.Position = offset;
output.Write(ms.GetBuffer(), (int)ms.Position, len);
ms.Position += len;
}
reader.Close();
output.Position = 0;
Global.Emulator.LoadStateBinary(new BinaryReader(output));
}
}
private void RewindOne()
{
if (!Global.Emulator.HasSavestates())
{
return;
}
var ms = _rewindBuffer.PopMemoryStream();
byte[] buf = ms.GetBuffer();
var reader = new BinaryReader(ms);
var fullstate = reader.ReadBoolean();
if (fullstate)
{
if (_rewindDeltaEnable)
{
UpdateLastState(buf, 1, buf.Length - 1);
}
Global.Emulator.AsStatable().LoadStateBinary(reader);
}
else
{
var output = new MemoryStream(_lastState);
int index = 1;
int offset = 0;
while (index < buf.Length)
{
int offsetDelta = (int)VLInteger.ReadUnsigned(buf, ref index);
int length = (int)VLInteger.ReadUnsigned(buf, ref index);
offset += offsetDelta;
output.Position = offset;
output.Write(buf, index, length);
index += length;
}
output.Position = 0;
Global.Emulator.AsStatable().LoadStateBinary(new BinaryReader(output));
output.Close();
}
reader.Close();
}
private MemoryStream GetPreviousStateMemoryStream()
{
if (_rewindDeltaEnable)
{
// When capturing deltas, the most recent state is stored in _lastState, and the
// last item in the rewind buffer gets us back to the previous state.
return(_rewindBuffer.PopMemoryStream());
}
else
{
// When capturing full states, the last item in the rewind buffer is the most
// recent state, so we need to get the item before it.
_rewindBuffer.Pop();
return(_rewindBuffer.PeekMemoryStream());
}
// Note that in both cases, after loading the state, we still have a copy of it
// either in _lastState or as the last item in the rewind buffer. This is good
// because once we resume capturing, the first capture doesn't happen until
// stepping forward to the following frame, which would result in a gap if we
// didn't still have a copy of the current state here.
}
