Thank you Rick - this is exactly what I was looking for.

Richard


>Richard,
>How about some "old" code I found awhile ago? To test it, I used:
>

>lcStr = "Most anything you want to put in here!"
>?transform(bobcrc(-1, lcStr, "16"), "@0x ")
>?transform(val(sys(2007, lcStr)), "@0x ")
>

>
>And now for the "generic" CRC routine (still with the credits!):
>

>* Program....: BOBCRC.PRG
>* Version....: 1.0
>* Author.....: Bob Herguth, Based upon PowerBASIC Code by Coridon Henshaw
>* Date.......: June 9, 1997
>* Compiler...: FoxPro 2.6a
>* Abstract...: 16 and 32 bit CRC calaculator routine for data blocks.
>*    lcBlockTxt: The text block to calculate a CRC for.
>*    lcBitLen: A text value ("16" or "32")indicating whether
>*       to return a 16 or 32 bit CRC.
>* Changes....:
>
>PARAMETERS lnStartVal, lcBlockTxt, lcBitLen
>DO CASE
> CASE PCOUNT() < 2
>  WAIT WINDOW "Not enough paramters passed to CRC(lnStartVal, lcBlockTxt, lcBitLen) function."
>  RETURN
> CASE PCOUNT() < 3
>  lcBitLen = "16"
>ENDCASE
>DIMENSION laPower[8]     && For the 8 laPowers of 2
>PRIVATE lnCRC, lnPower, TestBit
>lnBitLen = IIF(lcBitLen="32",32773,4129) && 1021 hex (16bit), 8005 hex (32bit)
>
>* Precalculated values will improve performance in FOR J Code
>FOR lnPower = 1 TO 8
> laPower[lnPower] = 2^(lnPower-1)
>NEXT lnPower
>
>lnCRC = lnStartVal       && Reset for Each Text Block
>FOR OutLoop = 1 TO LEN(lcBlockTxt)  && Calculate for Length of Block
> ByteVal = ASC(SUBSTR(lcBlockTxt, OutLoop, 1))
> FOR InLoop = 8 TO 1 STEP - 1
>  TestBit = ((BITAND(lnCRC,32768) = 32768) AND NOT (BITAND(ByteVal, laPower(InLoop)) = laPower(InLoop))) OR;
>   (!(BITAND(lnCRC,32768) = 32768) AND (BITAND(ByteVal, laPower(InLoop)) = laPower(InLoop)))
>  lnCRC = BITAND(lnCRC,32767)*2
>  IF TestBit
>   lnCRC = BITXOR(lnCRC,lnBitLen)
>  ENDIF
> NEXT InLoop
>NEXT OutLoop
>RETURN lnCRC      && Return the Word Value
>
>FUNCTION  Xd0bit
>PARAMETER Bitno, A
>PRIVATE Remainder, I, Highord
>Highord = INT(IIF(A>1,LOG(A)*1.442695041,0))
>IF Bitno>Highord
> RETURN .F.
>ENDIF
>FOR I = 0 TO Highord
> IF I=Bitno
>  RETURN IIF(IIF(A=1,1,MOD(A,2))=1,.T.,.F.)
> ENDIF
> IF A=0
>  RETURN .F.
> ENDIF
> A = INT(A/2)
>NEXT
>

>Rick