private void CreatePatchInternal()
{
Source.Position = 0;
Target.Position = 0;
ulong sourceSize = (ulong)Source.Length;
ulong targetSize = (ulong)Target.Length;
var sourceChecksum = ChecksumUtils.CalculateCRC32ForEntireStream(Source);
var targetChecksum = ChecksumUtils.CalculateCRC32ForEntireStream(Target);
// header
PatchOut.WriteUInt32(0x31535042, EndianUtils.Endianness.LittleEndian);
PatchOut.WriteUnsignedNumber(sourceSize);
PatchOut.WriteUnsignedNumber(targetSize);
PatchOut.WriteUnsignedNumber(0); // metadata
// actions
while (Target.Position < Target.Length)
{
int s;
int t;
bool advancedS;
bool advancedT;
if (IsNextByteSameInSourceAndTarget(out s, out t, out advancedS, out advancedT))
{
ulong count = 1;
while (IsNextByteSameInSourceAndTarget(out s, out t, out advancedS, out advancedT))
{
++count;
}
if (advancedS)
{
Source.Position -= 1;
}
if (advancedT)
{
Target.Position -= 1;
}
PatchOut.WriteAction(HyoutaUtils.Bps.Action.SourceRead, count);
}
else
{
if (advancedS)
{
Source.Position -= 1;
}
if (advancedT)
{
Target.Position -= 1;
}
long p = Target.Position;
ulong count = 0;
while (ShouldWriteNextByteFromTarget(out s, out t, out advancedS, out advancedT))
{
++count;
}
if (advancedS)
{
Source.Position -= 1;
}
PatchOut.WriteAction(HyoutaUtils.Bps.Action.TargetRead, count);
Target.Position = p;
StreamUtils.CopyStream(Target, PatchOut, (long)count);
}
}
PatchOut.WriteUInt32(sourceChecksum.Value, EndianUtils.Endianness.LittleEndian);
PatchOut.WriteUInt32(targetChecksum.Value, EndianUtils.Endianness.LittleEndian);
long checksumsize = PatchOut.Position;
PatchOut.Position = 0;
var patchChecksum = ChecksumUtils.CalculateCRC32FromCurrentPosition(PatchOut, checksumsize);
PatchOut.WriteUInt32(patchChecksum.Value, EndianUtils.Endianness.LittleEndian);
}