Determine if .NET assembly is Mixed Mode without calling external EXE in Powershell v3

Question

So I have written a Powershell script to get the Platform of any given exe\dll. I'm not familiar enough with the assembly headers to determine if a file has native code or not. I'm trying not to call corflags, peverify, ildasm, or any other external executable.

Is there an easy way to accomplish this? Here is the Powershell code I have so far for determining if an assembly is native or .NET and what platform it is built for. I want to add the ability if it's .NET to also determine if it's mixed mode.

# Gets the Platform of a any Assembly native or managed.
# Examples:
#   Get-Platform "C:\vs\projects\bestprojectever\bin\debug\mysweetproj.dll"
#   Get-Platform (dir *.dll | select -first 1) 

param([Parameter(Mandatory=$true, ValueFromPipeline=$true)] $assemblyPath)

$platform = "Unknown"
$resolvedPath = Resolve-Path -literalPath $assemblyPath

try {
    $architecture = [System.Reflection.AssemblyName]::GetAssemblyName($resolvedPath) | Select-Object -ExpandProperty ProcessorArchitecture
    switch ($architecture) {
        MSIL { $platform = "AnyCPU Managed" }
        X86 { $platform = "x86 Managed" }
        Amd64 { $platform = "x64 Managed" }
        IA64 { $platform = "Itanium Managed" }
        default { $platform = "Unknown Managed" }
    }
}
catch [System.BadImageFormatException] {
    try {
        $assemblyStream = [System.IO.File]::OpenRead($resolvedPath)
        try {
            $binaryReader = New-Object System.IO.BinaryReader($assemblyStream)
            if ($binaryReader.ReadUInt16() -eq 0x5A4D)
            {
                $ignore = $assemblyStream.Seek(0x3c, [System.IO.SeekOrigin]::Begin)
                $pos = $binaryReader.ReadInt32()
                $ignore = $assemblyStream.Seek($pos, [System.IO.SeekOrigin]::Begin)
                $format = $binaryReader.ReadUInt32()
                if ($format -eq 0x4550)
                {
                    $machineType = $binaryReader.ReadUInt16()
                }
            }
        }
        finally {
            if ($binaryReader -ne $null) {
                $binaryReader.Close();
                if ($binaryReader.psbase -eq $null) {
                    $binaryReader.Dispose()
                } else {
                    $binaryReader.psbase.Dispose()
                }
            }
        }
    }
    finally
    {
        if ($assemblyStream -ne $null) {
            $assemblyStream.Close();
            if ($assemblyStream.psbase -eq $null) {
                $assemblyStream.Dispose()
            } else {
                $assemblyStream.psbase.Dispose()
            }
        }
    }
    switch ($format)
    {
        0x454C { $platform = "Virtual Device Driver Native" }
        0x454E { $platform = "16bit Native" }
        0x4550
        {
            switch ($machineType)
            {
                0x14c { $platform = "x86 Native" }
                0x166 { $platform = "R4000 Native" }
                0x169 { $platform = "MIPS WCE v2 Native" }
                0x1a2 { $platform = "Hitachi SH3 Native" }
                0x1a3 { $platform = "Hitachi SH3 DSP Native" }
                0x1a6 { $platform = "Hitachi SH4 Native" }
                0x1a8 { $platform = "Hitachi SH5 Native" }
                0x1c0 { $platform = "ARM Native" }
                0x1c2 { $platform = "Thumb Native" }
                0x1d3 { $platform = "Matsushita AM33 Native" }
                0x1f0 { $platform = "Power PC Native" }
                0x1f1 { $platform = "Power PC with floating point support Native" }
                0x200 { $platform = "IA64 Native" }
                0x266 { $platform = "MIPS16 Native" }
                0x366 { $platform = "MIPS with FPU Native" }
                0x466 { $platform = "MIPS16 with FPU Native" }
                0xebc { $platform = "EFI Byte Code Native" }
                0x8664 { $platform = "x64 Native" }
                0x9041 { $platform = "Mitsubishi M32R Native" }
                0xc0ee { $platform = "Pure MSIL" }
                default { $platform = "Unknown Native" }
            }
        }
        default { $platform = "Unknown Format" }
    }
}

return $platform

Also I'm familiar with the following question and all the answers involve calling some external EXE which I am trying to avoid.

Answer 1

You might start from the code available here and adapt it to see if the IMAGE_COR20_HEADER contains the COMIMAGE_FLAGS_ILONLY (in that case, this is a non-mixed mode assembly).