Added ConvertFrom-Gzip cmdlet

Author: alan-null

filesystem/gzip.ps1

@@ -0,0 +1,33 @@
+function ConvertFrom-Gzip {
+    Param (
+        [Parameter(Mandatory = $true, ValueFromPipeline = $true)]
+        [ValidateScript( { (Get-Item $_).Name.EndsWith(".gz") })]
+        [System.IO.FileInfo]
+        $InputObject,
+
+        [Parameter(Mandatory = $false)]
+        [switch]
+        $RemoveInputFile
+    )
+    Process {
+        # Create a new file and open a filestream for it
+        $NewFilename = $InputObject.FullName.Remove($InputObject.FullName.Length - $InputObject.Extension.Length)
+        $DecompressedFileStream = [System.IO.File]::Create($NewFilename)
+
+        # Open the compressed file and copy the file to the decompressed stream
+        $CompressedFileStream = $InputObject.OpenRead()
+        $GZipStream = [System.IO.Compression.GZipStream]::new($CompressedFileStream, [System.IO.Compression.CompressionMode]::Decompress)
+        $GZipStream.CopyTo($DecompressedFileStream)
+
+        # Cleanup
+        $DecompressedFileStream.Dispose()
+        $GZipStream.Dispose()
+        $CompressedFileStream.Dispose()
+        $DecompressedFileStream, $GZipStream, $CompressedFileStream = $null
+
+        # Remove the initial file if requested.
+        if ($PSBoundParameters.ContainsKey('RemoveInputFile')) {
+            $InputObject.Delete()
+        }
+    }
+}