www.pudn.com > Indy_9_00_14_src.zip > IdHash.pas

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{ $Log:  10177: IdHash.pas  
{ 
{   Rev 1.0    2002.11.12 10:40:00 PM  czhower 
} 
unit IdHash; 
 
interface 
 
uses 
  Classes; 
 
type 
  TIdHash = class(TObject); 
 
  TIdHash16 = class(TIdHash) 
  public 
    function HashValue(const ASrc: string): Word; overload; 
    function HashValue(AStream: TStream): Word; overload; virtual; abstract; 
  end; 
 
  TIdHash32 = class(TIdHash) 
  public 
    function HashValue(const ASrc: string): LongWord; overload; 
    function HashValue(AStream: TStream): LongWord; overload; virtual; abstract; 
  end; 
 
  T4x4LongWordRecord = array [0..3] of LongWord; 
 
  TIdHash128 = class(TIdHash) 
  public 
    class function AsHex(const AValue: T4x4LongWordRecord): string; 
    function HashValue(const ASrc: string): T4x4LongWordRecord; overload; 
    function HashValue(AStream: TStream): T4x4LongWordRecord; overload; virtual; abstract; 
  end; 
 
implementation 
 
uses 
  IdGlobal, 
  SysUtils; 
 
{ TIdHash32 } 
 
function TIdHash32.HashValue(const ASrc: string): LongWord; 
var 
  LStream: TIdReadMemoryStream; 
begin 
  LStream := TIdReadMemoryStream.Create; try 
    LStream.SetPointer(Pointer(ASrc),Length(ASrc)); 
    Result := HashValue(LStream); 
  finally FreeAndNil(LStream); end; 
end; 
 
{ TIdHash16 } 
 
function TIdHash16.HashValue(const ASrc: string): Word; 
var 
  LStream: TIdReadMemoryStream; 
begin 
  LStream := TIdReadMemoryStream.Create; try 
    LStream.SetPointer(Pointer(ASrc),Length(ASrc)); 
    Result := HashValue(LStream); 
  finally FreeAndNil(LStream); end; 
end; 
 
{ TIdHash128 } 
 
function TIdHash128.HashValue(const ASrc: string): T4x4LongWordRecord; 
var 
  LStream: TIdReadMemoryStream; 
begin 
  LStream := TIdReadMemoryStream.Create; try 
    LStream.SetPointer(Pointer(ASrc),Length(ASrc)); 
    Result := HashValue(LStream); 
  finally FreeAndNil(LStream); end; 
end; 
 
class function TIdHash128.AsHex(const AValue: T4x4LongWordRecord): string; 
var 
  P: PChar; 
  i: Integer; 
Begin 
  P:=PChar(@AValue); 
  SetString(Result,NIL,4*4*2);//32 
  for i:=0 to 15 do begin 
    Result[i*2+1]:=IdHexDigits[ord(P[i]) shr 4]; 
    Result[i*2+2]:=IdHexDigits[ord(P[i]) and $F]; 
  end;//for 
end; 
 
end.