Write-IStreamToFile.ps1
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function Write-IStreamToFile([__ComObject] $istream, [string] $fileName) { # NOTE: We cannot use [System.Runtime.InteropServices.ComTypes.IStream], # since PowerShell apparently cannot convert an IStream COM object to this # Powershell type. (See http://stackoverflow.com/a/9037299/223837 for # details.) # It turns out that .NET/CLR _can_ do this conversion. # # That is the reason why method FileUtil.WriteIStreamToFile(), below, # takes an object, and casts it to an IStream, instead of directly # taking an IStream inputStream argument. $cp = New-Object CodeDom.Compiler.CompilerParameters $cp.CompilerOptions = "/unsafe" $cp.WarningLevel = 4 $cp.TreatWarningsAsErrors = $true Add-Type -CompilerParameters $cp -TypeDefinition @" using System; using System.IO; using System.Runtime.InteropServices.ComTypes; namespace My { public static class FileUtil { public static void WriteIStreamToFile(object i, string fileName) { IStream inputStream = i as IStream; FileStream outputFileStream = File.OpenWrite(fileName); int bytesRead = 0; int offset = 0; byte[] data; do { data = Read(inputStream, 2048, out bytesRead); outputFileStream.Write(data, 0, bytesRead); offset += bytesRead; } while (bytesRead == 2048); outputFileStream.Flush(); outputFileStream.Close(); } unsafe static private byte[] Read(IStream stream, int toRead, out int read) { byte[] buffer = new byte[toRead]; int bytesRead = 0; int* ptr = &bytesRead; stream.Read(buffer, toRead, (IntPtr)ptr); read = bytesRead; return buffer; } } } "@ [My.FileUtil]::WriteIStreamToFile($istream, $fileName) } |