Private/Test-MessageCRC.ps1
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Function Test-MessageCRC { [CmdletBinding()] param($iOInstance) $CRCStream = [ordered]@{} $i=0 do { #offset length index -1 for array count, and -2 for crc and -1 for etx $CRCOffset = ($iOInstance.ByteStreamReceive.ParsedStream[$i].Length -4) #get bytes for crc calculation $CRCTask = $iOInstance.ByteStreamReceive.ParsedStream[$i][1..($CRCOffset)] #Old crc is two bytes before etx $OldCRC = ($iOInstance.ByteStreamReceive.ParsedStream[$i][($CRCOffset +1)..($CRCOffset +2)] | ForEach-Object {"{0:x2}" -f $_}) -join "" #recalculate crc $NewCRC = Get-CRC16 -ByteData $CRCTask #compare crc Write-Verbose ("[CRC]: String to Compute: [" + $CRCTask + "]") Write-Verbose ("[CRC]: Received CRC: [" + $OldCRC + "]") Write-Verbose ("[CRC]: Computed CRC: [" + $NewCRC + "]") if (!($NewCRC -eq $OldCRC)) { $CRCStream.Add($i,$false) Write-Error ("CRC DOES NOT MATCH. Expected: " + $OldCRC + "Computed: " + $NewCRC) } else { $CRCStream.Add($i,$true) } $i++ } until ($iOInstance.ByteStreamReceive.ParsedStream.Count -eq $i) $iOInstance.ByteStreamReceive.Add("CRCStream",$CRCStream) return $iOInstance #compute/add CRC #CRC-16 is calculated [in these bytes] <STX>[<DST><SND><LEN><MSG>[<QRY>]]<CRC><CRC><ETX> } |