Powershell Byte array to INT

Question

I have a byte array with two values: 07 and DE (in hex).

What I need to do is somehow concatenate the 07DE and get the decimal value from that hex value. In this case, it is 2014.

My code:

# This line gives 11 bytes worth of information
[Byte[]] $hexbyte2 = $obj.OIDValueB

# All I need are the first two bytes (the values in this case are 07 and DE in HEX)
[Byte[]] $year = $hexbyte2[0], $hexbyte2[1]

How do I combined these to make 07DE and convert that to an int to get 2014?

Solution 1

Another option is to use the .NET System.BitConvert class:

C:\PS> $bytes = [byte[]](0xDE,0x07)
C:\PS> [bitconverter]::ToInt16($bytes,0)
2014

Solution 2

Accounting for Endianness while using the .NET System.BitConverter calss:

# This line gives 11 bytes worth of information
[Byte[]] $hexbyte2 = $obj.OIDValueB

# From the OP I'm assuming:
#   $hexbyte2[0] = 0x07
#   $hexbyte2[1] = 0xDE

$Endianness = if([System.BitConverter]::IsLittleEndian){1,0}else{0,1}
$year = [System.BitConverter]::ToInt16($hexbyte2[$Endianness],0)

Note, older versions of PowerShell would need to rework the if statement:

if([System.BitConverter]::IsLittleEndian){
   $Endianness = 1,0
}else{
   $Endianness = 0,1
}

see also MSDN: How to convert a byte array to an int (C# Programming Guide)

Solution 3

Here is one way that should work. First you convert the bytes into hex, then you can concatenate that and convert to an integer.

[byte[]]$hexbyte2 = 0x07,0xde
$hex = -Join (("{0:X}" -f $hexbyte2[0]),("{0:X}" -f $hexbyte2[1]))
([convert]::ToInt64($hex,16))