unit1.~pas

Delphi下几种CRC算法的实现例程

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    Memo1: TMemo;
    Button1: TButton;
    Edit1: TEdit;
    Label1: TLabel;
    Label2: TLabel;
    Edit2: TEdit;
    Label3: TLabel;
    Edit3: TEdit;
    Label4: TLabel;
    Edit4: TEdit;
    Label5: TLabel;
    Edit5: TEdit;
    Label6: TLabel;
    Edit6: TEdit;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
const crc_ta: 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);

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
var i,j,da,db:byte;
    Dats : array[0..20] of byte;
    Len,CrcH,CrcL:byte;
    Crc,Temp,TempH,TempL:word;
begin
  Len:=Memo1.Lines.Count;
  for i:=0 to Len-1 do begin
    Dats[i] := StrToInt('0x'+Memo1.Lines[i]);
    end;
//  按位计算
  Crc:=StrToInt('0x'+EDit5.text);
  for i:= 0 to len-1 do begin
    Da:=$80;
    for  j:=1 to 8 do begin
      if ((Crc and $8000)<>0) then begin
        Crc := Crc * 2;
        Crc :=Crc xor $1021;
        end
      else
        Crc := Crc * 2;
      if ((Dats[i] and Da)<>0) then  begin
        Crc := Crc xor $1021;
        end;
      Da := Da div  2;
      end;
    end;
  Edit2.Text:=IntToHex(Crc,4);
//查表法
  Crc:=StrToInt('0x'+EDit5.text);
  for i:=0 to Len-1 do begin
    da :=Crc div 256;
    Crc := Crc * 256;
    Crc := Crc xor (Crc_ta[da xor Dats[i]]);
    end;
  Edit1.Text := IntToHex(Crc,4);
//半字节
  Crc:=StrToInt('0x'+EDit5.text);
  for i:=0 to Len-1 do begin
    da :=Crc div 4096;
    Crc := Crc * 16;
    Crc := Crc xor ($1021 * (da xor (Dats[i] div 16)));

    da :=Crc div 4096;
    Crc := Crc * 16;
    Crc := Crc xor ($1021 * (da xor (Dats[i] and $0f)));
    end;
  Edit3.Text := IntToHex(Crc,4);
//半字节加速
  Crc:=StrToInt('0x'+EDit5.text);
  CrcH:=Crc div 256;
  CrcL:=Crc mod 256;
  for i:=0 to Len-1 do begin
    da := (Crc div 256) xor Dats[i];
    db:=da;
    Temp :=( $1021 * ( da and $f0)) xor ($1021 * ((da div 16 )xor (da and $0f)));
    Crc := (Crc * 256) xor Temp;

    db := CrcH xor Dats[i];
    TempH:=(db div 16 )xor (db and $0f);
//    CrcH:= CrcL xor (TempH*16+TempH div 8) xor ((db and $f0) div 8)  ;
    CrcH:= CrcL xor (TempH*16) xor (((db and $f0) xor TempH )div 8)  ;
    CrcL:= (db and $f0) xor ($21*(TempH));
    end;
  Edit4.Text := IntToHex(Crc,4);
  Edit6.Text := IntToHex(CrcH*256+CrcL,4);
end;

end.