usr/Get-Entropy.ps1
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Set-Alias -Name ent -Value Get-Entropy function Get-Entropy { <# .SYNOPSIS Computes entropy of a file or bytes sequence. .DESCRIPTION The function is primarily focused on calculating the entropy of huge files, but can be used for same purpose for bytes. .PARAMETER Path Specifies an item path. .PARAMETER Bytes Specifies a set of bytes. .EXAMPLE Get-Entropy C:\samples\target.bin .EXAMPLE Get-Entropy -Bytes ([IO.File]::ReadAllBytes('C:\samples\target.bin')) .INPUTS System.String System.Array .OUTPUTS System.Double #> [CmdletBinding(DefaultParameterSetName='Path')] param( [Parameter(Mandatory, Position=0, ParameterSetName='Path')] [ValidateScript({!!($script:file = Convert-Path -Path $_ -ErrorAction 0)})] [ValidateNotNullOrEmpty()] [String]$Path, [Parameter(Mandatory, Position=0, ParameterSetName='Bytes')] [ValidateNotNullOrEmpty()] [Byte[]]$Bytes ) end { $x = New-ILMethod -Noun $MyInvocation.MyCommand.Noun -Variables { Int32 $i Int32* $rng Int32* $pi Double $ent Double $src } -ReturnType ([Double]) -Parameters ([Byte[]]) -Code @' ldc_i4, 0x100 conv_u ldc_i4_4 mul_ovf_un localloc stloc_1 ldloc_1 ldc_i4, 0x400 conv_i add stloc_2 ldc_r8, 0.0 stloc_3 ldarg_0 ldlen conv_i4 dup stloc_0 conv_r8 stloc_s, $src br_s, :L_0 :L_1 # 0x28 ldloc_1 ldarg_0 ldloc_0 ldelem_u1 conv_i ldc_i4_4 mul add dup ldind_i4 ldc_i4_1 add stind_i4 :L_0 # 0x35 ldloc_0 ldc_i4_1 sub dup stloc_0 ldc_i4_0 bge_s, :L_1 br_s, :L_2 :L_3 # 0x3f ldloc_2 ldind_i4 ldc_i4_0 ble_s, :L_2 ldloc_3 ldloc_2 ldind_i4 conv_r8 ldloc_2 ldind_i4 conv_r8 ldloc_s, $src div ldc_r8, 2. call, [Math].GetMethod('Log', [Type[]]([Double], [Double])) mul add stloc_3 :L_2 # 0x5f ldloc_2 ldc_i4_4 conv_i sub dup stloc_2 ldloc_1 bge_un_s, :L_3 ldloc_3 neg ldloc_s, $src div ret '@ try { $x.Invoke($PSCmdlet.ParameterSetName -eq 'Path' ? [IO.File]::ReadAllBytes(($Path = $file)) : $Bytes ) } catch { Write-Verbose $_ } } } Export-ModuleMember -Alias ent -Function Get-Entropy |