支持4G以上文件的MD5单元

根据网上一个流传很久的基于Delph4的MD5单元修改的, 可以支持4G以上的文件, 可以支持UNICODE字符的Delphi

恩.......对于大文件速度稍微慢了一点点, 在我自己的电脑上测试, 5.2G文件计算速度86秒...凑合了吧

如果谁能优化一下速度, 请联系我哦~~~

(*
-----------------------------------------------------------------------------------------------

                                     MD5 Message-Digest

                                 Delphi Unit implementing the
                      RSA Data Security, Inc. MD5 Message-Digest Algorithm

                          Implementation of Ronald L. Rivest's RFC 1321

                      Copyright ?1997-1999 Medienagentur Fichtner & Meyer
                                  Written by Matthias Fichtner

-----------------------------------------------------------------------------------------------
2013-11-11 堕落恶魔
  增加对超过4G大小文件支持
  增加对Delphi2009以及更高版本Delphi支持

如果有修改, 希望能够将代码同步邮件给我, 谢谢
hs_kill_god@hotmail.com
-----------------------------------------------------------------------------------------------

*)

Unit MD5;

// -----------------------------------------------------------------------------------------------
interface
// -----------------------------------------------------------------------------------------------

uses
  Windows, Classes, SysUtils;

const
  MD5Length: Byte = ;

type
  MD5Count = array[..] of Int64;
  MD5State = array[..] of DWORD;
  MD5Block = array[..] of DWORD;
  MD5CBits = array[..] of byte;
  MD5Digest = array[..] of byte;
  MD5Buffer = array[..] of byte;

function MD5String(M: AnsiString): MD5Digest;
function MD5File(N: AnsiString): MD5Digest;
function MD5Print(D: MD5Digest): AnsiString;

function MD5Match(D1, D2: MD5Digest): boolean;

// -----------------------------------------------------------------------------------------------
IMPLEMENTATION
// -----------------------------------------------------------------------------------------------

var
  PADDING: MD5Buffer = (
    $, $, $, $, $, $, $, $,
    $, $, $, $, $, $, $, $,
    $, $, $, $, $, $, $, $,
    $, $, $, $, $, $, $, $,
    $, $, $, $, $, $, $, $,
    $, $, $, $, $, $, $, $,
    $, $, $, $, $, $, $, $,
    $, $, $, $, $, $, $, $
  );

type
  MD5Context = record
    State: MD5State;
    Count: MD5Count;
    Buffer: MD5Buffer;
  end;

function F(x, y, z: DWORD): DWORD; inline;
begin
  Result := (x and y) or ((not x) and z);
end;

function G(x, y, z: DWORD): DWORD; inline;
begin
  Result := (x and z) or (y and (not z));
end;

function H(x, y, z: DWORD): DWORD; inline;
begin
  Result := x xor y xor z;
end;

function I(x, y, z: DWORD): DWORD; inline;
begin
  Result := y xor (x or (not z));
end;

procedure rot(var x: DWORD; n: BYTE); inline;
begin
  x := (x shl n) or (x shr ( - n));
end;

procedure FF(var a: DWORD; b, c, d, x: DWORD; s: BYTE; ac: DWORD); inline;
begin
  inc(a, F(b, c, d) + x + ac);
  rot(a, s);
  inc(a, b);
end;

procedure GG(var a: DWORD; b, c, d, x: DWORD; s: BYTE; ac: DWORD); inline;
begin
  inc(a, G(b, c, d) + x + ac);
  rot(a, s);
  inc(a, b);
end;

procedure HH(var a: DWORD; b, c, d, x: DWORD; s: BYTE; ac: DWORD); inline;
begin
  inc(a, H(b, c, d) + x + ac);
  rot(a, s);
  inc(a, b);
end;

procedure II(var a: DWORD; b, c, d, x: DWORD; s: BYTE; ac: DWORD); inline;
begin
  inc(a, I(b, c, d) + x + ac);
  rot(a, s);
  inc(a, b);
end;

// -----------------------------------------------------------------------------------------------

// Encode Count bytes at Source into (Count / ) DWORDs at Target
procedure Encode(Source, Target: pointer; Count: longword);
var
  S: PByte;
  T: PDWORD;
  I: longword;
begin
  S := Source;
  T := Target;
  for I :=  to Count div  do
  begin
    T^ := S^;
    inc(S);
    T^ := T^ or (S^ shl );
    inc(S);
    T^ := T^ or (S^ shl );
    inc(S);
    T^ := T^ or (S^ shl );
    inc(S);
    inc(T);
  end;
end;

// Decode Count DWORDs at Source into (Count * ) Bytes at Target
procedure Decode(Source, Target: pointer; Count: longword);
var
  S: PDWORD;
  T: PByte;
  I: longword;
begin
  S := Source;
  T := Target;
  for I :=  to Count do
  begin
    T^ := S^ and $FF;
    inc(T);
    T^ := (S^ shr ) and $FF;
    inc(T);
    T^ := (S^ shr ) and $FF;
    inc(T);
    T^ := (S^ shr ) and $FF;
    inc(T);
    inc(S);
  end;
end;

function MP(P: Pointer; M: Integer): Pointer;
begin
  Result := Pointer(Integer(P) + M);
end;

// Transform State according to first  bytes at Buffer
procedure Transform(Buffer: pointer; var State: MD5State);
var
  a, b, c, d: DWORD;
  Block: MD5Block;
begin
  Encode(Buffer, @Block, );
  a := State[];
  b := State[];
  c := State[];
  d := State[];
  FF (a, b, c, d, Block[ ],  , $d76aa478);
  FF (d, a, b, c, Block[ ], , $e8c7b756);
  FF (c, d, a, b, Block[ ], , $242070db);
  FF (b, c, d, a, Block[ ], , $c1bdceee);
  FF (a, b, c, d, Block[ ],  , $f57c0faf);
  FF (d, a, b, c, Block[ ], , $4787c62a);
  FF (c, d, a, b, Block[ ], , $a8304613);
  FF (b, c, d, a, Block[ ], , $fd469501);
  FF (a, b, c, d, Block[ ],  , $698098d8);
  FF (d, a, b, c, Block[ ], , $8b44f7af);
  FF (c, d, a, b, Block[], , $ffff5bb1);
  FF (b, c, d, a, Block[], , $895cd7be);
  FF (a, b, c, d, Block[],  , $6b901122);
  FF (d, a, b, c, Block[], , $fd987193);
  FF (c, d, a, b, Block[], , $a679438e);
  FF (b, c, d, a, Block[], , $49b40821);
  GG (a, b, c, d, Block[ ],  , $f61e2562);
  GG (d, a, b, c, Block[ ],  , $c040b340);
  GG (c, d, a, b, Block[], , $265e5a51);
  GG (b, c, d, a, Block[ ], , $e9b6c7aa);
  GG (a, b, c, d, Block[ ],  , $d62f105d);
  GG (d, a, b, c, Block[],  ,  $);
  GG (c, d, a, b, Block[], , $d8a1e681);
  GG (b, c, d, a, Block[ ], , $e7d3fbc8);
  GG (a, b, c, d, Block[ ],  , $21e1cde6);
  GG (d, a, b, c, Block[],  , $c33707d6);
  GG (c, d, a, b, Block[ ], , $f4d50d87);
  GG (b, c, d, a, Block[ ], , $455a14ed);
  GG (a, b, c, d, Block[],  , $a9e3e905);
  GG (d, a, b, c, Block[ ],  , $fcefa3f8);
  GG (c, d, a, b, Block[ ], , $676f02d9);
  GG (b, c, d, a, Block[], , $8d2a4c8a);
  HH (a, b, c, d, Block[ ],  , $fffa3942);
  HH (d, a, b, c, Block[ ], , $8771f681);
  HH (c, d, a, b, Block[], , $6d9d6122);
  HH (b, c, d, a, Block[], , $fde5380c);
  HH (a, b, c, d, Block[ ],  , $a4beea44);
  HH (d, a, b, c, Block[ ], , $4bdecfa9);
  HH (c, d, a, b, Block[ ], , $f6bb4b60);
  HH (b, c, d, a, Block[], , $bebfbc70);
  HH (a, b, c, d, Block[],  , $289b7ec6);
  HH (d, a, b, c, Block[ ], , $eaa127fa);
  HH (c, d, a, b, Block[ ], , $d4ef3085);
  HH (b, c, d, a, Block[ ], ,  $4881d05);
  HH (a, b, c, d, Block[ ],  , $d9d4d039);
  HH (d, a, b, c, Block[], , $e6db99e5);
  HH (c, d, a, b, Block[], , $1fa27cf8);
  HH (b, c, d, a, Block[ ], , $c4ac5665);
  II (a, b, c, d, Block[ ],  , $f4292244);
  II (d, a, b, c, Block[ ], , $432aff97);
  II (c, d, a, b, Block[], , $ab9423a7);
  II (b, c, d, a, Block[ ], , $fc93a039);
  II (a, b, c, d, Block[],  , $655b59c3);
  II (d, a, b, c, Block[ ], , $8f0ccc92);
  II (c, d, a, b, Block[], , $ffeff47d);
  II (b, c, d, a, Block[ ], , $85845dd1);
  II (a, b, c, d, Block[ ],  , $6fa87e4f);
  II (d, a, b, c, Block[], , $fe2ce6e0);
  II (c, d, a, b, Block[ ], , $a3014314);
  II (b, c, d, a, Block[], , $4e0811a1);
  II (a, b, c, d, Block[ ],  , $f7537e82);
  II (d, a, b, c, Block[], , $bd3af235);
  II (c, d, a, b, Block[ ], , $2ad7d2bb);
  II (b, c, d, a, Block[ ], , $eb86d391);
  inc(State[], a);
  inc(State[], b);
  inc(State[], c);
  inc(State[], d);
end;

// -----------------------------------------------------------------------------------------------

// Initialize given Context
procedure MD5Init(var AContext: MD5Context);
begin
  with AContext do
  begin
    State[] := $;
    State[] := $EFCDAB89;
    State[] := $98BADCFE;
    State[] := $;
    Count[] := ;
    Count[] := ;
    FillChar(Buffer, SizeOf(MD5Buffer), );
  end;
end;

// Update given Context to include Length bytes of Input
procedure MD5Update(var AContext: MD5Context; AInput: Pointer; ALength: Int64); overload;
var
  nIndex: Int64;
  nPartLen: Int64;
  I: Int64;
begin
  with AContext do
  begin
    nIndex := (Count[] shr ) and $3F;
    inc(Count[], ALength shl );
    if Count[] < (ALength shl ) then
      inc(Count[]);
    inc(Count[], ALength shr );
  end;
  nPartLen :=  - nIndex;
  if ALength >= nPartLen then
  begin
    Move(AInput^, AContext.Buffer[nIndex], nPartLen);
    Transform(@AContext.Buffer, AContext.State);
    I := nPartLen;
    while I +  < ALength do
    begin
      Transform(MP(AInput,  I), AContext.State);
      inc(I, );
    end;
    nIndex := ;
  end
  else
    I := ;
  Move(MP(AInput,  I)^, AContext.Buffer[nIndex], ALength - i);
end;

procedure MD5Update(var AContext: MD5Context; AInput: TStream; ALength: Int64); overload;
var
  nIndex: Int64;
  nPartLen: Int64;
  i: Int64;
  x, m: Integer;
  nBuff: array[..] of Byte;
begin
  with AContext do
  begin
    nIndex := (Count[] shr ) and $3F;
    inc(Count[], ALength shl );
    if Count[] < (ALength shl ) then
      inc(Count[]);
    inc(Count[], ALength shr );
  end;
  nPartLen :=  - nIndex;
  if ALength >= nPartLen then
  begin
    AInput.Read(AContext.Buffer[nIndex], nPartLen);
    Transform(@AContext.Buffer, AContext.State);
    i := nPartLen;
    while i < ALength -  do
    begin
      AInput.Read(nBuff, );
      for x :=  to  do
        Transform(@(nBuff[x * ]), AContext.State);
      Inc(i, );
    end;
    m := (ALength - i) div ;
    x := m * ;
    AInput.Read(nBuff, x);
    Inc(I, x);
    for x :=  to m -  do
      Transform(@(nBuff[x * ]), AContext.State);
    nIndex := ;
  end
  else
    i := ;
  AInput.Read(AContext.Buffer[nIndex], ALength - i);
end;

// Finalize given Context, create Digest and zeroize Context
procedure MD5Final(var AContext: MD5Context; var Digest: MD5Digest);
var
  nBits: MD5CBits;
  nIndex: longword;
  nPadLen: longword;
begin
  Decode(@AContext.Count, @nBits, );
  nIndex := (AContext.Count[] shr ) and $3f;
  if nIndex <  then
    nPadLen :=  - nIndex
  else
    nPadLen :=  - nIndex;
  MD5Update(AContext, @PADDING, nPadLen);
  MD5Update(AContext, @nBits, );
  Decode(@AContext.State, @Digest, );
  FillChar(AContext, SizeOf(MD5Context), );
end;

// -----------------------------------------------------------------------------------------------

// Create digest of given Message
function MD5String(M: AnsiString): MD5Digest;
var
  nContext: MD5Context;
begin
  MD5Init(nContext);
  MD5Update(nContext, pAnsiChar(M), length(M));
  MD5Final(nContext, Result);
end;

// Create digest of file with given Name
function MD5File(N: AnsiString): MD5Digest;
var
  nContext: MD5Context;
  nFS: TFileStream;
begin
  MD5Init(nContext);
  if FileExists(N) then
  begin
    nFS := TFileStream.Create(N, fmOpenRead or fmShareDenyWrite);
    try
      nFS.Position := ;
      MD5Update(nContext, nFS, nFS.Size);
    finally
      nFS.Free;
    end;
  end;
  MD5Final(nContext, Result);
end;

// Create hex representation of given Digest
function MD5Print(D: MD5Digest): AnsiString;
var
  I, x: byte;
const
  Digits: array[..] of AnsiChar =
    ('', '', '', '', '', '', '', '', '', '', 'a', 'b', 'c', 'd', 'e', 'f');
begin
  SetLength(Result, );
  for I :=  to  do
  begin
    x := i *  + ;
    Result[x] := Digits[(D[I] shr ) and $0f];
    Result[x + ] := Digits[D[I] and $0f];
  end;
end;

// -----------------------------------------------------------------------------------------------

// Compare two Digests
function MD5Match(D1, D2: MD5Digest): boolean;
var
  I: byte;
begin
  I := ;
  Result := TRUE;
  while Result and (I < ) do
  begin
    Result := D1[I] = D2[I];
    inc(I);
  end;
end;

end.