program CrcTest;
function ReflectLoByte(aValue: Cardinal): Cardinal;
begin
aValue := (aValue and $f0) shr 4 or (aValue and $0f) shl 4;
aValue := (aValue and $cc) shr 2 or (aValue and $33) shl 2;
Result := (aValue and $aa) shr 1 or (aValue and $55) shl 1;
end;
function Crc8Maxim(const aData: string): Cardinal;
var
I, J: LongInt;
begin
Result := 0;
for I := 1 to Length(aData) do
begin
Result := Result xor ReflectLoByte(Ord(aData[I]));
for J := 1 to 8 do
if Result and $80 <> 0 then
Result := Result shl 1 xor $31
else
Result := Result shl 1;
end;
Result := ReflectLoByte(Result) and $ff;
end;
function Crc8Maxim_2(const aBuffer: string): Cardinal;
var
CrcTable: array of Cardinal;
I: LongInt;
begin
CrcTable := [
$00, $5e, $bc, $e2, $61, $3f, $dd, $83, $c2, $9c, $7e, $20, $a3, $fd, $1f, $41,
$9d, $c3, $21, $7f, $fc, $a2, $40, $1e, $5f, $01, $e3, $bd, $3e, $60, $82, $dc,
$23, $7d, $9f, $c1, $42, $1c, $fe, $a0, $e1, $bf, $5d, $03, $80, $de, $3c, $62,
$be, $e0, $02, $5c, $df, $81, $63, $3d, $7c, $22, $c0, $9e, $1d, $43, $a1, $ff,
$46, $18, $fa, $a4, $27, $79, $9b, $c5, $84, $da, $38, $66, $e5, $bb, $59, $07,
$db, $85, $67, $39, $ba, $e4, $06, $58, $19, $47, $a5, $fb, $78, $26, $c4, $9a,
$65, $3b, $d9, $87, $04, $5a, $b8, $e6, $a7, $f9, $1b, $45, $c6, $98, $7a, $24,
$f8, $a6, $44, $1a, $99, $c7, $25, $7b, $3a, $64, $86, $d8, $5b, $05, $e7, $b9,
$8c, $d2, $30, $6e, $ed, $b3, $51, $0f, $4e, $10, $f2, $ac, $2f, $71, $93, $cd,
$11, $4f, $ad, $f3, $70, $2e, $cc, $92, $d3, $8d, $6f, $31, $b2, $ec, $0e, $50,
$af, $f1, $13, $4d, $ce, $90, $72, $2c, $6d, $33, $d1, $8f, $0c, $52, $b0, $ee,
$32, $6c, $8e, $d0, $53, $0d, $ef, $b1, $f0, $ae, $4c, $12, $91, $cf, $2d, $73,
$ca, $94, $76, $28, $ab, $f5, $17, $49, $08, $56, $b4, $ea, $69, $37, $d5, $8b,
$57, $09, $eb, $b5, $36, $68, $8a, $d4, $95, $cb, $29, $77, $f4, $aa, $48, $16,
$e9, $b7, $55, $0b, $88, $d6, $34, $6a, $2b, $75, $97, $c9, $4a, $14, $f6, $a8,
$74, $2a, $c8, $96, $15, $4b, $a9, $f7, $b6, $e8, $0a, $54, $d7, $89, $6b, $35];
Result := 0;
for I := 1 to Length(aBuffer) do
Result := CrcTable[Result xor Ord(aBuffer[I])];
end;
function HexDecode(const aOrigin: string): string;
var
I, CurPos: LongInt;
begin
CurPos := 1;
SetLength(Result, Length(aOrigin) div 2 + Length(aOrigin) and 1);
for I := 1 to Length(Result) do
begin
Result[I] := Chr(StrToInt('$' + Copy(aOrigin, CurPos, 2)));
CurPos := CurPos + 2;
end;
end;
function GetByteHexEdit(aIndex: LongInt): Byte;
begin
if aIndex = 3 then
Result := 5
else
Result := 0;
end;
function GetByteSequence: string;
var
I: LongInt;
begin
SetLength(Result, 14);
for I := 1 to Length(Result) do
Result[I] := Chr(GetByteHexEdit(I - 1));
end;
var
s: string;
c: Cardinal;
begin
WriteStr('Crc8Maxim results:');
WriteStr('self test:');
s := '123456789';
c := Crc8Maxim(s);
WriteCardAsHex(c);
WriteStr('hexadecimal string:');
s := '0000000500000000000000000000';
c := Crc8Maxim(HexDecode(s));
WriteCardAsHex(c);
WriteStr('byte sequence:');
s := GetByteSequence;
c := Crc8Maxim(s);
WriteCardAsHex(c);
WriteStr('');
WriteStr('Crc8Maxim_2 results:');
WriteStr('self test:');
s := '123456789';
c := Crc8Maxim_2(s);
WriteCardAsHex(c);
WriteStr('hexadecimal string:');
s := '0000000500000000000000000000';
c := Crc8Maxim_2(HexDecode(s));
WriteCardAsHex(c);
WriteStr('byte sequence:');
s := GetByteSequence;
c := Crc8Maxim_2(s);
WriteCardAsHex(c);
end.
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