| public static CompressMemory ( byte original, int origStart, int origLength, byte changed, int changedStart, int changedLength ) : byte[] | ||
| original | byte | An array containing the original block of memory. |
| origStart | int | The offset within the array where the original block /// starts. |
| origLength | int | The length of the original block, in bytes. |
| changed | byte | An array containing the changed block to be compressed. |
| changedStart | int | The offset within the array where the changed /// block starts. |
| changedLength | int | The length of the changed block. This may be
/// greater than |
| return | byte[] | |
public static byte[] CompressMemory(byte[] original, int origStart, int origLength,
byte[] changed, int changedStart, int changedLength)
{
if (origStart + origLength > original.Length)
throw new ArgumentException("Original array is too small");
if (changedStart + changedLength > changed.Length)
throw new ArgumentException("Changed array is too small");
if (changedLength < origLength)
throw new ArgumentException("New block must be no smaller than old block");
MemoryStream mstr = new MemoryStream();
BigEndian.WriteInt32(mstr, (uint)changedLength);
for (int i = 0; i < origLength; i++)
{
byte b = (byte)(original[origStart+i] ^ changed[changedStart+i]);
if (b == 0)
{
int runLength;
for (runLength = 1; i + runLength < origLength; runLength++)
{
if (runLength == 256)
break;
if (original[origStart + i + runLength] != changed[changedStart + i + runLength])
break;
}
mstr.WriteByte(0);
mstr.WriteByte((byte)(runLength - 1));
i += runLength - 1;
}
else
mstr.WriteByte(b);
}
return mstr.ToArray();
}
