I was messing around with the BitArray class (patch to follow) when i
realised that it might be faster to use unsafe code to swap the bytes. So i
did a test or two and it turns out that for longs it's faster to use unsafe
code and copy bytes around.
This makes SwapLong ~20% faster (0.2x faster).
Is it ok to commit?
Alan.
Index: C:/programming/mcs/class/System/System.Net/IPAddress.cs
===================================================================
--- C:/programming/mcs/class/System/System.Net/IPAddress.cs (revision 74962)
+++ C:/programming/mcs/class/System/System.Net/IPAddress.cs (working copy)
@@ -71,14 +71,20 @@
private static long SwapLong(long number)
{
- return (((number >> 56) & 0xFF)
- | ((number >> 40) & 0xFF00)
- | ((number >> 24) & 0xFF0000)
- | ((number >> 08) & 0xFF000000)
- | ((number << 08) & 0xFF00000000)
- | ((number << 24) & 0xFF0000000000)
- | ((number << 40) & 0xFF000000000000)
- | ((number << 56)));
+ long result;
+ byte* rPtr = (byte*)&result;
+ byte* oPtr = (byte*)&number;
+
+ *(rPtr + 7) = *(oPtr + 0);
+ *(rPtr + 6) = *(oPtr + 1);
+ *(rPtr + 5) = *(oPtr + 2);
+ *(rPtr + 4) = *(oPtr + 3);
+ *(rPtr + 3) = *(oPtr + 4);
+ *(rPtr + 2) = *(oPtr + 5);
+ *(rPtr + 1) = *(oPtr + 6);
+ *(rPtr + 0) = *(oPtr + 7);
+
+ return result;
}
public static short HostToNetworkOrder(short host) {
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