Category : Pascal Source Code
Archive   : BPLUS.ZIP
Filename : CRC.PAS
{$B+} {Boolean complete evaluation on}
{$S+} {Stack checking on}
{$I+} {I/O checking on}
{$N-} {No numeric coprocessor}
Unit crc;
Interface
const
CRC_XMODEM_POLY = $1021;
crc_table : array [0..255] of word = (
$0000, $1021, $2042, $3063, $4084, $50A5, $60C6, $70E7,
$8108, $9129, $A14A, $B16B, $C18C, $D1AD, $E1CE, $F1EF,
$1231, $0210, $3273, $2252, $52B5, $4294, $72F7, $62D6,
$9339, $8318, $B37B, $A35A, $D3BD, $C39C, $F3FF, $E3DE,
$2462, $3443, $0420, $1401, $64E6, $74C7, $44A4, $5485,
$A56A, $B54B, $8528, $9509, $E5EE, $F5CF, $C5AC, $D58D,
$3653, $2672, $1611, $0630, $76D7, $66F6, $5695, $46B4,
$B75B, $A77A, $9719, $8738, $F7DF, $E7FE, $D79D, $C7BC,
$48C4, $58E5, $6886, $78A7, $0840, $1861, $2802, $3823,
$C9CC, $D9ED, $E98E, $F9AF, $8948, $9969, $A90A, $B92B,
$5AF5, $4AD4, $7AB7, $6A96, $1A71, $0A50, $3A33, $2A12,
$DBFD, $CBDC, $FBBF, $EB9E, $9B79, $8B58, $BB3B, $AB1A,
$6CA6, $7C87, $4CE4, $5CC5, $2C22, $3C03, $0C60, $1C41,
$EDAE, $FD8F, $CDEC, $DDCD, $AD2A, $BD0B, $8D68, $9D49,
$7E97, $6EB6, $5ED5, $4EF4, $3E13, $2E32, $1E51, $0E70,
$FF9F, $EFBE, $DFDD, $CFFC, $BF1B, $AF3A, $9F59, $8F78,
$9188, $81A9, $B1CA, $A1EB, $D10C, $C12D, $F14E, $E16F,
$1080, $00A1, $30C2, $20E3, $5004, $4025, $7046, $6067,
$83B9, $9398, $A3FB, $B3DA, $C33D, $D31C, $E37F, $F35E,
$02B1, $1290, $22F3, $32D2, $4235, $5214, $6277, $7256,
$B5EA, $A5CB, $95A8, $8589, $F56E, $E54F, $D52C, $C50D,
$34E2, $24C3, $14A0, $0481, $7466, $6447, $5424, $4405,
$A7DB, $B7FA, $8799, $97B8, $E75F, $F77E, $C71D, $D73C,
$26D3, $36F2, $0691, $16B0, $6657, $7676, $4615, $5634,
$D94C, $C96D, $F90E, $E92F, $99C8, $89E9, $B98A, $A9AB,
$5844, $4865, $7806, $6827, $18C0, $08E1, $3882, $28A3,
$CB7D, $DB5C, $EB3F, $FB1E, $8BF9, $9BD8, $ABBB, $BB9A,
$4A75, $5A54, $6A37, $7A16, $0AF1, $1AD0, $2AB3, $3A92,
$FD2E, $ED0F, $DD6C, $CD4D, $BDAA, $AD8B, $9DE8, $8DC9,
$7C26, $6C07, $5C64, $4C45, $3CA2, $2C83, $1CE0, $0CC1,
$EF1F, $FF3E, $CF5D, $DF7C, $AF9B, $BFBA, $8FD9, $9FF8,
$6E17, $7E36, $4E55, $5E74, $2E93, $3EB2, $0ED1, $1EF0
);
var
crc_16 : word;
{
Init_CRC initializes for XMODEM style CRC calculation by setting
crc_16 to value. Typically value is 0 for XMODEM and -1 for
B+ Protocl. It returns the initial value.
}
function Init_CRC (value : word) : word;
function Upd_CRC (value : word) : word;
{===========================================================================}
Implementation
{
* crc.inc - Turbo Pascal (TM)
*
* Calculates XMODEM-style CRC (uses the CCITT V.41 polynomial but
* completely backwards from the normal bit ordering).
*
* This was derived from CRC.C, which itself was derived from
* work done by Gary Brown, CompuServe Incorporated, and likely
* from other sources as well.
*
}
function Init_CRC (value : word) : word;
begin
crc_16 := value;
Init_CRC := value;
end;
{
Upd_CRC updates crc_16 and returns the updated value.
}
function Upd_CRC (value : word) : word;
begin
crc_16 := crc_table [((crc_16 shr 8) xor (value)) and $ff] xor
(crc_16 shl 8);
Upd_CRC := crc_16;
end;
End.
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This is so awesome! 😀 I’d be cool if you could download an entire archive of this at once, though.
But one thing that puzzles me is the “mtswslnkmcjklsdlsbdmMICROSOFT” string. There is an article about it here. It is definitely worth a read: http://www.os2museum.com/wp/mtswslnk/