How can I take two bytes and combine them into a single UInt16 in C#?

Question

I want to have a method with the body:

public UInt16 ReadMemory16(Byte[] memory, UInt16 address)
{
    // read two bytes at the predefined address
}

So, I want to get the value at memory[address] AND the next byte and combine them into a single UInt16.

For the order of the bytes, the machine I'm implementing is little endian if that matters. How do I get both of those byte values and combine them into a single UInt16 in C#?

Answer 1

Use a bitshift:

return (ushort)((memory[address + 1] << 8) + memory[address]);

You could use the BitConverter class but be aware that there is a static readonly field called IsLittleEndian that you should check before using it. If it already set to little endian then you can use this class, but if it is set to the wrong value you cannot modify it.

Alternatively you could take a look at Jon Skeet's MiscUtil library which includes as EndianBitConverter class that allows you to specify the endianness.

Answer 2

One way is to use the BitConverter class:

public UInt16 ReadMemory16(Byte[] memory, UInt16 address)
{
    return System.BitConverter.ToUInt16(memory, address);
}

This will interpret the bytes according to the native endianness on the machine.

Answer 3

You can use Bitconverter.ToUInt16: http://msdn.microsoft.com/en-us/library/system.bitconverter.touint16(v=VS.85).aspx