So I was using BitConverter.GetBytes() to convert uint32 to byte[], but my the order in the array seems to be backwards. http://msdn.microsoft.com/en-us/library/1184xdy4.aspx (shows that it's byte[] seems to be little endian).
Is there a better way handle this than just using linq to reverse the byte arrays?
Array.Reverse to change the endianess.
If you are going to be moving between platform architectures simply reversing the array might be correct on one platform, but fail on a platform that is already using big endian.
You use the IPAddress.HostToNetworkOrder functions, which will ensure that the data is always in network order (big endian).
uint number = 234234233;
uint bigEndian = (uint)IPAddress.HostToNetworkOrder((int)number);
byte[] b = BitConverter.GetBytes(bigEndian);
Microsoft discusses the little-endian / big-endian issue with the GetBytes() method on the documentation page for BitConverter.
So I figured out a big part of my confusion is related to this: IsLittleEndian field reports false, but it must be Little-Endian?
What I ended up doing was wrapping all the BitConverter calls with call that took an extra parameter to specifiy endianness, then added a function that gets called to check to see if the bytes need to be revered.
public static class BitEndianConverter
{
public static byte[] GetBytes(bool value, bool littleEndian)
{
return ReverseAsNeeded(BitConverter.GetBytes(value), littleEndian);
}
public static byte[] GetBytes(char value, bool littleEndian)
{
return ReverseAsNeeded(BitConverter.GetBytes(value), littleEndian);
}
public static byte[] GetBytes(double value, bool littleEndian)
{
return ReverseAsNeeded(BitConverter.GetBytes(value), littleEndian);
}
public static byte[] GetBytes(float value, bool littleEndian)
{
return ReverseAsNeeded(BitConverter.GetBytes(value), littleEndian);
}
public static byte[] GetBytes(int value, bool littleEndian)
{
return ReverseAsNeeded(BitConverter.GetBytes(value), littleEndian);
}
public static byte[] GetBytes(long value, bool littleEndian)
{
return ReverseAsNeeded(BitConverter.GetBytes(value), littleEndian);
}
public static byte[] GetBytes(short value, bool littleEndian)
{
return ReverseAsNeeded(BitConverter.GetBytes(value), littleEndian);
}
public static byte[] GetBytes(uint value, bool littleEndian)
{
return ReverseAsNeeded(BitConverter.GetBytes(value), littleEndian);
}
public static byte[] GetBytes(ulong value, bool littleEndian)
{
return ReverseAsNeeded(BitConverter.GetBytes(value), littleEndian);
}
public static byte[] GetBytes(ushort value, bool littleEndian)
{
return ReverseAsNeeded(BitConverter.GetBytes(value), littleEndian);
}
private static byte[] ReverseAsNeeded(byte[] bytes, bool wantsLittleEndian)
{
if (wantsLittleEndian == BitConverter.IsLittleEndian)
return bytes;
else
return (byte[])bytes.Reverse().ToArray();
}
}
Following is a method to always get big endian byte array quickly.
public static byte[] GetBigEndianBytes(UInt32 val, bool isLittleEndian)
{
UInt32 bigEndian = val;
if (isLittleEndian)
{
bigEndian = (val & 0x000000FFU) << 24 | (val & 0x0000FF00U) << 8 |
(val & 0x00FF0000U) >> 8 | (val & 0xFF000000U) >> 24;
}
return BitConverter.GetBytes(bigEndian);
}
This overload can be handy, although care must be taken when working across machines with different endian-nesses.
public static byte[] GetBigEndianBytes(UInt32 val)
{
return GetBigEndianBytes(val, BitConverter.IsLittleEndian);
}
