Public/string/ConvertFrom-MisencodedString.ps1
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#Requires -Version 5.1 function ConvertFrom-MisencodedString { <# .SYNOPSIS Converts a misencoded string by reinterpreting bytes from a source encoding .DESCRIPTION Fixes encoding issues where text was incorrectly interpreted using the wrong character encoding. The function takes the string, converts it to bytes using the source encoding (default: Cyrillic), then reinterprets those bytes as ASCII or another target encoding. This is commonly needed when text was stored or transmitted using one encoding but displayed or processed as another, resulting in garbled characters. Note: PowerShell converts null input to an empty string before parameter validation runs, so passing -String $null is equivalent to -String ''. .PARAMETER String The misencoded string to convert. Accepts input from the pipeline. Empty strings are allowed and will be returned unchanged. Note: null values are automatically converted to empty strings by PowerShell. .PARAMETER SourceEncoding The encoding that was incorrectly applied to the original text. Default is 'Cyrillic' (windows-1251). Common values include 'Cyrillic', 'windows-1252', 'iso-8859-1', 'utf-8'. .PARAMETER TargetEncoding The encoding to use when reinterpreting the bytes. Default is 'ASCII'. Use 'utf-8' for broader character support. .EXAMPLE ConvertFrom-MisencodedString -String 'portal' Converts a Cyrillic-misencoded string back to readable ASCII text. Returns the corrected string. .EXAMPLE 'portal', 'server' | ConvertFrom-MisencodedString Pipeline example: processes multiple misencoded strings and returns the corrected versions. .EXAMPLE ConvertFrom-MisencodedString -String 'cafe' -SourceEncoding 'windows-1252' -TargetEncoding 'utf-8' Fixes a string where UTF-8 characters were misinterpreted as Windows-1252. Returns 'cafe' in proper UTF-8 encoding. .EXAMPLE Get-Content -Path 'C:\Logs\misencoded.txt' | ConvertFrom-MisencodedString Reads misencoded lines from a file and converts each line to the correct encoding. .OUTPUTS System.String The re-encoded string with correct character rendering. .NOTES Author: Franck SALLET Version: 1.0.2 Last Modified: 2026-03-11 Requires: PowerShell 5.1+ Permissions: None required Module: PSWinOps .LINK https://github.com/k9fr4n/PSWinOps .LINK https://learn.microsoft.com/en-us/dotnet/api/system.text.encoding #> [CmdletBinding()] [OutputType([string])] param( [Parameter(Mandatory = $true, ValueFromPipeline = $true, ValueFromPipelineByPropertyName = $true)] [AllowEmptyString()] [string]$String, [Parameter(Mandatory = $false)] [ValidateNotNullOrEmpty()] [string]$SourceEncoding = 'Cyrillic', [Parameter(Mandatory = $false)] [ValidateNotNullOrEmpty()] [string]$TargetEncoding = 'ASCII' ) begin { Write-Verbose "[$($MyInvocation.MyCommand)] Starting conversion - PowerShell $($PSVersionTable.PSVersion)" try { $sourceEncoder = [System.Text.Encoding]::GetEncoding($SourceEncoding) Write-Verbose "[$($MyInvocation.MyCommand)] Source encoding: $($sourceEncoder.EncodingName)" } catch { Write-Error "[$($MyInvocation.MyCommand)] Invalid source encoding '$SourceEncoding': $_" throw } try { $targetEncoder = [System.Text.Encoding]::GetEncoding($TargetEncoding) Write-Verbose "[$($MyInvocation.MyCommand)] Target encoding: $($targetEncoder.EncodingName)" } catch { Write-Error "[$($MyInvocation.MyCommand)] Invalid target encoding '$TargetEncoding': $_" throw } } process { # Handle empty strings without attempting conversion if ($String.Length -eq 0) { Write-Verbose "[$($MyInvocation.MyCommand)] Empty string - returning unchanged" return '' } try { Write-Verbose "[$($MyInvocation.MyCommand)] Processing: '$String'" $bytes = $sourceEncoder.GetBytes($String) $result = $targetEncoder.GetString($bytes) Write-Verbose "[$($MyInvocation.MyCommand)] Converted successfully (Length: $($String.Length) --> $($result.Length))" $result } catch [System.Text.EncoderFallbackException] { Write-Error "[$($MyInvocation.MyCommand)] Encoding fallback error for '$String': $_" return } catch [System.ArgumentException] { Write-Error "[$($MyInvocation.MyCommand)] Invalid characters in string for encoding '$SourceEncoding': $_" return } catch { Write-Error "[$($MyInvocation.MyCommand)] Conversion failed for string '$String': $_" return } } end { Write-Verbose "[$($MyInvocation.MyCommand)] Completed" } } |