Delphi MD5

unit uMD5;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics;

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

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

procedure MD5Init(var Context: MD5Context);
procedure MD5Update(var Context: MD5Context; Input: PAnsiChar; Length: longword);
procedure MD5Final(var Context: MD5Context; var Digest: MD5Digest);
function MD5File(N: string): MD5Digest;
function MD5Print(D: MD5Digest): AnsiString;
function MD5F(FileName: AnsiString): AnsiString;
function MD5S(Str: AnsiString): AnsiString;

function MD5FileText(filename: AnsiString): AnsiString;

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

implementation

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

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

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

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

procedure rot(var x: DWORD; N: Byte);
begin
  x := (x shl N) or (x shr ( - N));
end;

procedure FF(var a: DWORD; b, c, D, x: DWORD; s: Byte; ac: DWORD);
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);
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);
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);
begin
  inc(a, I(b, c, D) + x + ac);
  rot(a, s);
  inc(a, b);
end;

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;

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;

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;

procedure MD5Init(var Context: MD5Context);
begin
  with Context do
  begin
    State[] := $;
    State[] := $EFCDAB89;
    State[] := $98BADCFE;
    State[] := $;
    Count[] := ;
    Count[] := ;
    ZeroMemory(@Buffer, SizeOf(MD5Buffer));
  end;
end;

procedure MD5Update(var Context: MD5Context; Input: PAnsiChar; Length: longword);
var
  Index: longword;
  PartLen: longword;
  I: longword;
begin
  with Context do
  begin
    Index := (Count[] shr ) and $3F;
    inc(Count[], Length shl );
    if Count[] < (Length shl ) then
      inc(Count[]);
    inc(Count[], Length shr );
  end;
  PartLen :=  - Index;
  if Length >= PartLen then
  begin
    CopyMemory(@Context.Buffer[Index], Input, PartLen);
    Transform(@Context.Buffer, Context.State);
    I := PartLen;
    while I +  < Length do
    begin
      Transform(@Input[I], Context.State);
      inc(I, );
    end;
    Index := ;
  end
  else
    I := ;
  CopyMemory(@Context.Buffer[Index], @Input[I], Length - I);
end;

procedure MD5Final(var Context: MD5Context; var Digest: MD5Digest);
var
  Bits: MD5CBits;
  Index: longword;
  PadLen: longword;
begin
  Decode(@Context.Count, @Bits, );
  Index := (Context.Count[] shr ) and $3F;
  if Index <  then
    PadLen :=  - Index
  else
    PadLen :=  - Index;
  MD5Update(Context, @PADDING, PadLen);
  MD5Update(Context, @Bits, );
  Decode(@Context.State, @Digest, );
  ZeroMemory(@Context, SizeOf(MD5Context));
end;

function MD5String(M: AnsiString): MD5Digest;
var
  Context: MD5Context;
begin
  MD5Init(Context);
  MD5Update(Context, PAnsiChar(M), Length(M));
  MD5Final(Context, Result);
end;

function MD5File(N: string): MD5Digest;
var
  FileHandle: THandle;
  MapHandle: THandle;
  ViewPointer: pointer;
  Context: MD5Context;
begin
  MD5Init(Context);
  FileHandle := CreateFile(PWideChar(WideString(N)), GENERIC_READ, FILE_SHARE_READ or FILE_SHARE_WRITE, nil, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL or FILE_FLAG_SEQUENTIAL_SCAN, );
  if FileHandle <> INVALID_HANDLE_VALUE then
  try
    MapHandle := CreateFileMapping(FileHandle, nil, PAGE_READONLY, , , nil);
    if MapHandle <>  then
    try
      ViewPointer := MapViewOfFile(MapHandle, FILE_MAP_READ, , , );
      if ViewPointer <> nil then
      try
        MD5Update(Context, ViewPointer, GetFileSize(FileHandle, nil));
      finally
        UnmapViewOfFile(ViewPointer);
      end;
    finally
      CloseHandle(MapHandle);
    end;
  finally
    CloseHandle(FileHandle);
  end;
  MD5Final(Context, Result);
end;

function MD5Print(D: MD5Digest): AnsiString;
var
  I: Byte;
const
  Digits: array[..] of Ansichar = ('', '', '', '', '', '', '', '', '', '', 'a', 'b', 'c', 'd', 'e', 'f');
begin
  Result := '';
  for I :=  to  do
    Result := Result + Digits[(D[I] shr ) and $0F] + Digits[D[I] and $0F];
end;

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;

function MD5F(FileName: AnsiString): AnsiString;
begin
  Result := MD5Print(MD5File(string(FileName)));
end;

function MD5S(Str: AnsiString): AnsiString;
begin
  Result := MD5Print(MD5String(Str));
end;

function GetRamdomText(len: Integer): string;
var
  I: Integer;
begin
  Result := '';
  Randomize;
  for I :=  to Len -  do
  begin
    Result := Result + Char( + Random());
  end;
end;

function MD5FileText(filename: AnsiString): AnsiString;
var
  buf: array[..MAX_PATH - ] of Char;
  path: AnsiString;
  stream: TFileStream;
  destStream: TMemoryStream;
  destfile: string;
  tmpText: string;

  strstream: TStringStream;
begin
  GetTempPath(Length(buf), @buf[]);
  path := AnsiString(string(buf));
  tmpText := ExtractFileName(filename);
  tmpText := Copy(tmpText, , Length(tmpText) - );

  strstream := TStringStream.Create(tmpText, TEncoding.UTF8);
  strstream.Position := ;

  stream := TFileStream.Create(filename, fmOpenRead);
  try
    destStream := TMemoryStream.Create;
    try
      stream.Position := ;
      destStream.CopyFrom(stream, stream.Size);

      destfile := path + '\' + GetRamdomText();
      if FileExists(destfile) then
        DeleteFile(destfile);

      destStream.CopyFrom(strstream, strstream.Size);
      destStream.SaveToFile(destfile);
      strstream.Free;

      Result := MD5F(destfile);
    finally
      destStream.Free;
    end;
  finally
    stream.Free;
  end;

  if FileExists(destfile) then
    DeleteFile(destfile);
end;

end.