Show-FileEncoding function written in PowerShell

Show-FileEncoding_function.ps1

########################################################################################################
# 
#  .SYNOPSIS
#   
#     PowerShell function that returns the file encoding name as a string.
#      
#        _____ _                        ______ _ _      ______                     _ _             
#       / ____| |                      |  ____(_) |    |  ____|                   | (_)            
#      | (___ | |__   _____      ______| |__   _| | ___| |__   _ __   ___ ___   __| |_ _ __   __ _ 
#       \___ \| '_ \ / _ \ \ /\ / /____|  __| | | |/ _ \  __| | '_ \ / __/ _ \ / _` | | '_ \ / _` |
#       ____) | | | | (_) \ V  V /     | |    | | |  __/ |____| | | | (_| (_) | (_| | | | | | (_| |
#      |_____/|_| |_|\___/ \_/\_/      |_|    |_|_|\___|______|_| |_|\___\___/ \__,_|_|_| |_|\__, |
#                                                                                             __/ |
#                                                                                            |___/ 
#  .DESCRIPTION
#   
#     The Show-FileEncoding function determines encoding by looking at Byte Order Mark (BOM), or
#      if no BOM then by reading the file to determine if it is ASCII or UTF-8
#  
#  .PARAMETER Path
#   
#     Path to the file to be examined
#  
#  .EXAMPLE
#   
#     Show-ChildItem  *.ps1 | select FullName, @{n='Encoding';e={Show-FileEncoding $_.FullName}} | where {$_.Encoding -ne 'ASCII'}
#     This command gets ps1 files in current directory where encoding is not ASCII
#  
#  .EXAMPLE
#   
#     Show-ChildItem  *.ps1 | select FullName, @{n='Encoding';e={Show-FileEncoding $_.FullName}} | where {$_.Encoding -ne 'ASCII'} | foreach {(get-content $_.FullName) | set-content $_.FullName -Encoding ASCII}
#     Same as previous example but fixes encoding using set-content
#  
#  .INPUTS
#   
#     None.  This command does not accept pipeline input.
#  
#  .OUTPUTS
#   
#     String
#  
#  .NOTES
#    
#     Derived by Larry Weiss (lfw@airmail.net) from
#     a version by Franck Richard at
#       http://franckrichard.blogspot.de/2010/08/powershell-get-encoding-file-type.html
#     that was based on a port of C# code by Rick Strahl from
#       http://www.west-wind.com/Weblog/posts/197245.aspx
#   
#  .LINK
#   
#     References:
#       http://unicode.org/faq/utf_bom.html
#       http://en.wikipedia.org/wiki/Byte_order_mark
#  
########################################################################################################

function Show-FileEncoding {

  [CmdletBinding()] 
  
  param (
  
    [string]
    [Parameter(Mandatory = $True, ValueFromPipelineByPropertyName = $True)] 
    $Path
    
   )

  [byte[]] $bytes = $null
   
  [byte[]] $b = get-content -Encoding byte -ReadCount 4 -TotalCount 4 -Path $Path
  if ( $b.count -eq 0 ) {
    'ASCII'
    return
   }
  if ( $b[0] -eq 0xef -and $b[1] -eq 0xbb -and $b[2] -eq 0xbf ) {
    'UTF8'
   }
  elseif ( $b[0] -eq 0xfe -and $b[1] -eq 0xff ) {
    'Unicode UTF-16 Big-Endian'
   }
  elseif ( $b[0] -eq 0xff -and $b[1] -eq 0xfe ) {
    'Unicode UTF-16 Little-Endian'
   }
  elseif ( $b[0] -eq 0 -and $b[1] -eq 0 -and $b[2] -eq 0xfe -and $b[3] -eq 0xff ) {
    'UTF32 Big-Endian'
   }
  elseif ( $b[0] -eq 0xfe -and $b[1] -eq 0xff -and $b[2] -eq 0 -and $b[3] -eq 0 ) {
    'UTF32 Little-Endian'
   }
  elseif ( $b[0] -eq 0x2b -and $b[1] -eq 0x2f -and $b[2] -eq 0x76 -and ($b[3] -eq 0x38 -or $b[3] -eq 0x39 -or $b[3] -eq 0x2b -or $b[3] -eq 0x2f) ) {
    'UTF7'
   }
  elseif ( $b[0] -eq 0xf7 -and $b[1] -eq 0x64 -and $b[2] -eq 0x4c ) {
    'UTF-1'
   }
  elseif ( $b[0] -eq 0xdd -and $b[1] -eq 0x73 -and $b[2] -eq 0x66 -and $b[3] -eq 0x73 ) {
    'UTF-EBCDIC'
   }
  elseif ( $b[0] -eq 0x0e -and $b[1] -eq 0xfe -and $b[2] -eq 0xff ) {
    'SCSU'
   }
  elseif ( $b[0] -eq 0xfb -and $b[1] -eq 0xee -and $b[2] -eq 0x28 ) {
    'BOCU-1'
   }
  elseif ( $b[0] -eq 0x84 -and $b[1] -eq 0x31 -and $b[2] -eq 0x95 -and $b[3] -eq 0x33 ) {
    'GB-18030'
   }
  else {
    $bytes = [IO.File]::ReadAllBytes((Resolve-Path $Path)) 
    foreach ( $byte in $bytes ) {
      if ( $byte -gt 0x7f) {
        "UTF8" + "!" + $byte
        return
       }
     }
    'ASCII'
   }
 }