nanoid-ps.psm1
|
using namespace System.Numerics $ErrorActionPreference = 'Stop' [string] $DefaultAlphabet = '_-0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ' [CryptoRandom] $Random = [CryptoRandom]::new() function New-NanoId { [CmdletBinding()] [OutputType([string])] param( [Random]$Random = $script:Random, [ValidateNotNullOrEmpty()] [string] $Alphabet = $script:DefaultAlphabet, [ValidateRange(1, 255)] [int] $Size = 21) if ($Alphabet.Length -le 0 -or $Alphabet.Length -ge 256) { throw [ArgumentOutOfRangeException]("Alphabet must contain between 1 and 255 symbols. Received $($Alphabet.Length) chars."); } # See https://github.com/ai/nanoid/blob/master/format.js for explanation why masking # is used (`random % alphabet` is a common mistake security-wise). $Mask = (2 -shl 31 - [BitOperations]::LeadingZeroCount(($Alphabet.Length - 1) -bor 1)) - 1 $Step = [int][Math]::Ceiling(1.6 * $Mask * $Size / $Alphabet.Length) Write-Verbose "Step: $Step" #-Verbose $IdBuilder = [char[]]::new($Size) $Buffer = [byte[]]::new($Step) $cnt = 0; for ($cnt; $cnt -lt $size ; $cnt++ ) { $Random.NextBytes($Buffer); for ($i = 0; $i -lt $Step; $i++) { $AlphabetIndex = $Buffer[$i] -band $Mask; if ($AlphabetIndex -ge $Alphabet.Length) { continue } $IdBuilder[$cnt] = $Alphabet[$AlphabetIndex] } } $RetVal = [string]::new($IdBuilder) Write-Verbose "NanoId: $RetVal" #-Verbose return $RetVal } |