Is it possible to convert a byte array to a 8-bit signed integer array in Powershell?

问题

I am trying to convert a Hex string to an 8-bit signed integer array in Powershell.

I am using the following function to convert a Hex string, such as A591BF86E5D7D9837EE7ACC569C4B59B, to a byte array which I then need to convert to a 8-bit signed integer array.

Function GetByteArray {

    [cmdletbinding()]

    param(
        [parameter(Mandatory=$true)]
        [String]
        $HexString
    )

    $Bytes = [byte[]]::new($HexString.Length / 2)

    For($i=0; $i -lt $HexString.Length; $i+=2){
        $Bytes[$i/2] = [convert]::ToByte($HexString.Substring($i, 2), 16)
    }

    $Bytes  
}

After using the function the hex is converted to a byte array such as this:

I need to take the unsigned byte array and convert o to 8bit signed byte array, like the one below:

Is this possible? If so how can it be implemented?

I've tried using the BitConverter class but, as far as I saw, it can only convert to int16.

Thanks in advance

回答1:

To get a [byte[]] array ([byte] == System.Byte, an unsigned 8-bit integer type):

$hexStr = 'A591BF86E5D7D9837EE7ACC569C4B59B' # sample input

[byte[]] ($hexStr -split '(.{2})' -ne '' -replace '^', '0X')

-split '(.{2})' splits the input string by 2-character sequences, and enclosure in (...) causes these sequences to be included in the returned tokens; -ne '' then weeds out the empty tokens (which are technically the actual data tokens).
-replace , '^', '0X' places prefix 0X before each resulting 2-hex-digit string, yielding array '0XA5', '0X91', ...
casting the result to [byte[]] helpfully recognizes this hex format directly.
- Note: If you forget the cast, you'll get an array of strings.

To get an [sbyte[]] array ([sbyte] == System.SByte, a signed 8-bit integer), cast directly to [sbyte[]] instead; do not try to combine the casts: ~~[sbyte[]] [byte[]] (...)~~)

If you're given a [byte[]] array that you then want to convert to [sbyte[]], use the following (there may be more efficient approaches):

[byte[]] $bytes = 0x41, 0xFF # sample input; decimal: 65, 255

# -> [sbyte] values of:  65, -1
[sbyte[]] $sBytes = ($bytes.ForEach('ToString', 'X') -replace '^', '0X')

Applied to your sample values, in decimal notation:

# Input array of [byte]s.
[byte[]] $bytes = 43, 240, 82, 109, 185, 46, 111, 8, 164, 74, 164, 172
# Convert to an [sbyte] array.
[sbyte[]] $sBytes = ($bytes.ForEach('ToString', 'X') -replace '^', '0X')
$sBytes # Output (each signed byte prints on its own line, in decimal form).

Output:

来源：https://stackoverflow.com/questions/60065244/is-it-possible-to-convert-a-byte-array-to-a-8-bit-signed-integer-array-in-powers

标签

arrays

powershell

type-conversion

signed