GetGuidsFromCppInterfaceHeader.ps1

$CppHeaderFilePath = 'path/to/something.h'
$interfaceDefinition = Get-Content $CppHeaderFilePath -Raw
$flags = [Reflection.BindingFlags]::NonPublic -bor [Reflection.BindingFlags]::Instance
$fields = @{
    _a = [guid].GetField('_a', $flags)
    _b = [guid].GetField('_b', $flags)
    _c = [guid].GetField('_c', $flags)
    _d = [guid].GetField('_d', $flags)
    _e = [guid].GetField('_e', $flags)
    _f = [guid].GetField('_f', $flags)
    _g = [guid].GetField('_g', $flags)
    _h = [guid].GetField('_h', $flags)
    _i = [guid].GetField('_i', $flags)
    _j = [guid].GetField('_j', $flags)
    _k = [guid].GetField('_k', $flags)
}

$sb = [Text.StringBuilder]::new()
$allMatches = [regex]::Matches($interfaceDefinition, 'MIDL_INTERFACE\("([a-fA-F0-9\-]+)"\)\s+(I\p{L}+)\p{Zs}') |
    Sort-Object { $PSItem.Groups[2].Value }

$null = for ($i = 0; $i -lt $allMatches.Count; $i++) {
    if ($i -ne 0) {
        $sb.AppendLine().AppendLine();
    }

    $guid = [guid]$allMatches[$i].Groups[1].Value
    $sb.Append('public static readonly Guid ').
        Append($allMatches[$i].Groups[2].Value).
        Append(' = new Guid(').
        AppendFormat('0x{0:X8}', $fields['_a'].GetValue($guid)).
        Append(', ').
        AppendFormat('0x{0:X4}', $fields['_b'].GetValue($guid)).
        Append(', ').
        AppendFormat('0x{0:X4}', $fields['_c'].GetValue($guid)).
        Append(', ').
        AppendFormat('0x{0:X2}', $fields['_d'].GetValue($guid)).
        Append(', ').
        AppendFormat('0x{0:X2}', $fields['_e'].GetValue($guid)).
        Append(', ').
        AppendFormat('0x{0:X2}', $fields['_f'].GetValue($guid)).
        Append(', ').
        AppendFormat('0x{0:X2}', $fields['_g'].GetValue($guid)).
        Append(', ').
        AppendFormat('0x{0:X2}', $fields['_h'].GetValue($guid)).
        Append(', ').
        AppendFormat('0x{0:X2}', $fields['_i'].GetValue($guid)).
        Append(', ').
        AppendFormat('0x{0:X2}', $fields['_j'].GetValue($guid)).
        Append(', ').
        AppendFormat('0x{0:X2}', $fields['_k'].GetValue($guid)).
        Append(');')
}

$sb.ToString()