DELPHI如何实现CRC校验?
DELPHI如何实现CRC校验?想写个小程序?用CRC校验防破解?那为能给个例子看看? 刚来的 不清楚/:012 CRC8算法DELPHI源码unit Crc8;
inte**ce
Uses
Classes, Windows;
Function Crc_8n(p : array of BYTE; len : BYTE) : Byte;
implementation
Function Crc_8n(p : array of BYTE; len : BYTE) : Byte;
Var
j, cbit, aout, crc, crc_a, crc_b : Byte;
i : integer;
begin
crc := 0;
i := 0;
// 取移位的位
repeat
crc_a := p;
inc(i);
j := 8;
cbit := 1;
repeat
crc_b := crc_a;
crc_b := crc_b xor crc; // ?????
aout := crc_b and cbit;
if aout<>0 then begin
crc := crc xor $18; // ?????
crc := crc shr 1;
crc := crc or $80;
end else begin
crc := crc shr 1;
end;
crc_a := crc_a shr 1;
dec(j);
until j = 0;
dec(len);
until len = 0;
result := crc;
end;
end.
=================================
unit main;
inte**ce
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls,
Crc8;
type
TForm1 = class(TForm)
Edit1: TEdit;
Memo1: TMemo;
Button1: TButton;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
const MinBase = 2;
MaxBase = 36;
function StrToNum (const s: string; base: Integer;
neg: Boolean; max: Integer): Integer;
// s = 要转换的字符串
// base = 进制数
// neg = 是否为负数
// max = 要转换的最大数//
// 用法:
// i:= StrToNum (''''''''00101101'''''''', 2, false, MaxInt);
// i:= StrToNum (''''''''002D'''''''', 16, false, MaxInt);
// i:= StrToNum (''''''''-45'''''''', 10, true, MaxInt);
// i:= StrToNum (''''''''ZZ'''''''', 36, true, MaxInt);
//
var negate, done: Boolean;
i, len, digit, mmb: Integer;
c: Char;
mdb, res: Integer;
begin
res:= 0;i:= 1;digit:= 0;
if (base >= MinBase) and (base <= MaxBase) then begin
mmb:= max mod base;
mdb:= max div base;
len:= Length (s);
negate:= False;
while (i <= len) and (s = '''' '''') do Inc (i);
if neg then begin
case s of
''''+'''': Inc (i);
''''-'''': beginInc (i);negate:= TRUE; end;
end; (* CASE *)
end; (* IF neg *)
done:= len > i;
while (i <= len) and done do begin
c:= Upcase (s);
case c of
''''0''''..''''9'''': digit:= ORD(c) - 48;
''''A''''..''''Z'''': digit:= ORD(c) - 55;
else done:= FALSE
end; (* CASE *)
done:= done and (digit < base);
if done then begin
done:= (res < mdb) or ((res = mdb) and (digit <= mmb));
IF done then begin
res:= res * base + digit;
Inc (i);
end; (* IF done *)
end; (* IF done *)
end; (* WHILE *)
if negate then res:= - res;
end; (* IF done *)
Result:= res;
end;
procedure TForm1.Button1Click(Sender: TObject);
Var
S : String;
P : Array of Byte;
Len : Byte;
R : Byte;
I : Integer;
begin
S := Edit1.Text;
if length(s) mod 2 = 1 then s := s + ''''0'''';
Memo1.Lines.Add(S + '''' :'''');
for i:=1 to length(s) div 2 do begin
p := BYTE(StrToNum(copy(s, (i-1)*2+1, 2), 16, false, 500));
Memo1.Lines.Add(IntToStr(I) + '''' --> '''' + IntToHex(p, 2));
end;
Len := length(s) div 2;
R := Crc_8n(P, Len);
Memo1.Lines.Add(''''Crc8 Result: '''' + IntToHex(R, 2));
end;
end.
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