md5.pas

unit md5;
{$IFDEF FPC}{$MODE DELPHI}{$ENDIF}
 
interface
 
uses Windows, SysUtils, Classes;
 
type
  PMD5Digest = ^TMD5Digest;
  TMD5Digest = record
     case Integer of
        0: (A, B, C, D: LongInt);
        1: (v: array[0..15] of Byte);
      end;
function MD5String(const S: string): TMD5Digest;
function MD5File(const FileName: string): TMD5Digest;
function MD5Stream(const Stream: TStream): TMD5Digest;
function MD5Buffer(const Buffer;
Size: Integer): TMD5Digest;
function MD5DigestToStr(const Digest:
TMD5Digest): string;
function MD5DigestCompare(const Digest1,
Digest2: TMD5Digest): Boolean;
 
implementation
 
type
  UINT4 = LongWord;
 
    PArray4UINT4 = ^TArray4UINT4;
  TArray4UINT4 = array[0..3] of UINT4;
  PArray2UINT4 = ^TArray2UINT4;
  TArray2UINT4 = array[0..1] of UINT4;
  PArray16Byte = ^TArray16Byte;
  TArray16Byte = array[0..15] of Byte;
  PArray64Byte = ^TArray64Byte;
  TArray64Byte = array[0..63] of Byte;
 
    PByteArray = ^TByteArray;
  TByteArray = array[0..0] of Byte;
 
    PUINT4Array = ^TUINT4Array;
  TUINT4Array = array[0..0] of UINT4;
 
    PMD5Context = ^TMD5Context;
  TMD5Context = record
      state: TArray4UINT4;
      count: TArray2UINT4;
      buffer: TArray64Byte;
    end;
 
     const
       S11 = 7;
     S12 = 12;
     S13 = 17;
     S14 = 22;
     S21 = 5;
     S22 = 9;
     S23 = 14;
     S24 = 20;
     S31 = 4;
     S32 = 11;
     S33 = 16;
     S34 = 23;
     S41 = 6;
     S42 = 10;
     S43 = 15;
     S44 = 21;
 
     var
      Padding: TArray64Byte =
    ($80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
 
 
 
function _F(x, y, z:
UINT4): UINT4;
begin
  Result := (((x) and (y)) or ((not x) and (z)));
end;
 
 
function _G(x, y, z:
UINT4): UINT4;
begin
  Result := (((x) and (z)) or ((y)
   and (not z)));
end;
 
 
function _H(x, y, z:
UINT4): UINT4;
begin
  Result := ((x)xor (y)
   xor (z));
end;
 
 
function _I(x, y, z:
UINT4): UINT4;
begin
  Result := ((y)xor ((x)
   or (not z)));
end;
 
 
function ROTATE_LEFT(x, n: UINT4): UINT4;
begin
  Result := (((x)shl (n))
   or ((x)shr (32 - (n))));
end;
 
 
procedure FF(var a: UINT4; b,
c, d, x, s, ac: UINT4);
begin
   a := a + _F(b, c, d)
   + x + ac;
   a := ROTATE_LEFT(a, s);
   a := a + b;
end;
 
 
procedure GG(var a: UINT4; b,
c, d, x, s, ac: UINT4);
begin
  a := a + _G(b, c, d)
   + x + ac;
  a := ROTATE_LEFT(a, s);
  a := a + b;
end;
 
 
 
procedure HH(var a: UINT4; b,
c, d, x, s, ac: UINT4);
begin
  a := a + _H(b, c, d)
   + x + ac;
  a := ROTATE_LEFT(a, s);
  a := a + b;
end;
 
 
procedure II(var a: UINT4; b,
c, d, x, s, ac: UINT4);
begin
  a := a + _I(b, c, d)
   + x + ac;
  a := ROTATE_LEFT(a, s);
  a := a + b;
end;
 
 
procedure MD5Encode(Output: PByteArray; Input: PUINT4Array; Len: LongWord);
var
  i, j: LongWord;
begin
  j := 0;
  i := 0;
  while j  < Len do begin
     output[j] := Byte(input[i] and $FF);
   output[j + 1] := Byte((input[i]shr 8)
   and $FF);
   output[j + 2] := Byte((input[i]shr 16)
   and $FF);
   output[j + 3] := Byte((input[i]shr 24)
   and $FF);
   Inc(j, 4);
   Inc(i);
  end;
end;
 
 
procedure MD5Decode(Output: PUINT4Array; Input: PByteArray; Len: LongWord);
var
  i, j: LongWord;
begin
  j := 0;
  i := 0;
  while j  < Len do
    begin
     Output[i] := UINT4(input[j])
     or (UINT4(input[j + 1])shl 8)
     or
        (UINT4(input[j + 2])shl 16)
     or (UINT4(input[j + 3])shl 24);
     Inc(j, 4);
     Inc(i);
    end;
end;
 
 
procedure MD5_memcpy(Output:
PByteArray; Input: PByteArray; Len: LongWord);
begin
  Move(Input^, Output^, Len);
end;
 
 
procedure MD5_memset(Output:
PByteArray; Value: Integer; Len: LongWord);
begin
  FillChar(Output^, Len, Byte(Value));
end;
 
 
procedure MD5Transform(State: PArray4UINT4; Buffer: PArray64Byte);
var
  a, b, c, d: UINT4;
x: array[0..15] of UINT4;
begin
  a := State[0];
b := State[1];
c := State[2];
d := State[3];
  MD5Decode(PUINT4Array(@x), PByteArray(Buffer), 64);
 
    FF(a, b, c, d,
   x[0], S11, $D76AA478);
  FF(d, a, b,
   c, x[1], S12, $E8C7B756);
  FF(c, d, a, b,
   x[2], S13, $242070DB);
  FF(b, c, d,
   a, x[3], S14, $C1BDCEEE);
  FF(a, b, c, d,
   x[4], S11, $F57C0FAF);
  FF(d, a, b,
   c, x[5], S12, $4787C62A);
  FF(c, d, a, b,
   x[6], S13, $A8304613);
  FF(b, c, d,
   a, x[7], S14, $FD469501);
  FF(a, b, c, d,
   x[8], S11, $698098D8);
  FF(d, a, b,
   c, x[9], S12, $8B44F7AF);
  FF(c, d, a, b,
   x[10], S13, $FFFF5BB1);
  FF(b, c, d,
   a, x[11], S14, $895CD7BE);
  FF(a, b, c, d,
   x[12], S11, $6B901122);
  FF(d, a, b,
   c, x[13], S12, $FD987193);
  FF(c, d, a, b,
   x[14], S13, $A679438E);
  FF(b, c, d,
   a, x[15], S14, $49B40821);
 
    GG(a, b, c, d,
   x[1], S21, $F61E2562);
  GG(d, a, b,
   c, x[6], S22, $C040B340);
  GG(c, d, a, b,
   x[11], S23, $265E5A51);
  GG(b, c, d,
   a, x[0], S24, $E9B6C7AA);
  GG(a, b, c, d,
   x[5], S21, $D62F105D);
  GG(d, a, b,
   c, x[10], S22,  $2441453);
  GG(c, d, a, b,
   x[15], S23, $D8A1E681);
  GG(b, c, d,
   a, x[4], S24, $E7D3FBC8);
  GG(a, b, c, d,
   x[9], S21, $21E1CDE6);
  GG(d, a, b,
   c, x[14], S22, $C33707D6);
  GG(c, d, a, b,
   x[3], S23, $F4D50D87);
 
    GG(b, c, d,
   a, x[8], S24, $455A14ED);
  GG(a, b, c, d,
   x[13], S21, $A9E3E905);
  GG(d, a, b,
   c, x[2], S22, $FCEFA3F8);
  GG(c, d, a, b,
   x[7], S23, $676F02D9);
  GG(b, c, d,
   a, x[12], S24, $8D2A4C8A);
 
    HH(a, b, c, d,
   x[5], S31, $FFFA3942);
  HH(d, a, b,
   c, x[8], S32, $8771F681);
  HH(c, d, a, b,
   x[11], S33, $6D9D6122);
  HH(b, c, d,
   a, x[14], S34, $FDE5380C);
  HH(a, b, c, d,
   x[1], S31, $A4BEEA44);
  HH(d, a, b,
   c, x[4], S32, $4BDECFA9);
  HH(c, d, a, b,
   x[7], S33, $F6BB4B60);
  HH(b, c, d,
   a, x[10], S34, $BEBFBC70);
  HH(a, b, c, d,
   x[13], S31, $289B7EC6);
  HH(d, a, b,
   c, x[0], S32, $EAA127FA);
  HH(c, d, a, b,
   x[3], S33, $D4EF3085);
  HH(b, c, d,
   a, x[6], S34,  $4881d05);
  HH(a, b, c, d,
   x[9], S31, $D9D4D039);
  HH(d, a, b,
   c, x[12], S32, $E6DB99E5);
  HH(c, d, a, b,
   x[15], S33, $1FA27CF8);
  HH(b, c, d,
   a, x[2], S34, $C4AC5665);
 
    II(a, b, c, d,
   x[0], S41, $F4292244);
  II(d, a, b,
   c, x[7], S42, $432AFF97);
  II(c, d, a, b,
   x[14], S43, $AB9423A7);
  II(b, c, d,
   a, x[5], S44, $FC93A039);
  II(a, b, c, d,
   x[12], S41, $655B59C3);
  II(d, a, b,
   c, x[3], S42, $8F0CCC92);
  II(c, d, a, b,
   x[10], S43, $FFEFF47D);
  II(b, c, d,
   a, x[1], S44, $85845DD1);
  II(a, b, c, d,
   x[8], S41, $6FA87E4F);
  II(d, a, b,
   c, x[15], S42, $FE2CE6E0);
  II(c, d, a, b,
   x[6], S43, $A3014314);
  II(b, c, d,
   a, x[13], S44, $4E0811A1);
  II(a, b, c, d,
   x[4], S41, $F7537E82);
  II(d, a, b,
   c, x[11], S42, $BD3AF235);
  II(c, d, a, b,
   x[2], S43, $2AD7D2BB);
  II(b, c, d,
   a, x[9], S44, $EB86D391);
 
    Inc(State[0], a);
  Inc(State[1], b);
  Inc(State[2], c);
  Inc(State[3], d);
 
    MD5_memset (PByteArray(@x), 0, SizeOf(x));
end;
 
 
 
procedure MD5Init(var Context: TMD5Context);
begin
  FillChar(Context, SizeOf(Context), 0);
  Context.state[0] := $67452301;
  Context.state[1] := $EFCDAB89;
  Context.state[2] := $98BADCFE;
  Context.state[3] := $10325476;
end;
 
 
procedure MD5Update(var Context:
TMD5Context; Input: PByteArray; InputLen: LongWord);
var
  i, index, partLen: LongWord;
 
begin
  index := LongWord((context.count[0]shr 3)
   and $3F);
  Inc(Context.count[0], UINT4(InputLen)shl 3);
  if Context.count[0] < UINT4(InputLen)shl 3
   then Inc(Context.count[1]);
  Inc(Context.count[1], UINT4(InputLen)shr 29);
  partLen := 64 - index;
  if inputLen >= partLen then
begin
     MD5_memcpy(PByteArray(@Context.buffer[index]),
     Input, PartLen);
     MD5Transform(@Context.state, @Context.buffer);
     i := partLen;
     while i + 63 < inputLen do
   begin
        MD5Transform(@Context.state,
       PArray64Byte(@Input[i]));
        Inc(i, 64);
 
   end;
     index := 0;
    end
else
   i := 0;
    MD5_memcpy(PByteArray(@Context.buffer[index]),
     PByteArray(@Input[i]), inputLen - i);
end;
 
 
 
procedure MD5Final(var Digest: TMD5Digest; var Context:
TMD5Context);
var
  bits: array[0..7] of Byte;
index, padLen: LongWord;
begin
  MD5Encode(PByteArray(@bits), PUINT4Array(@Context.count),
   8);
  index := LongWord((Context.count[0]shr 3)
   and $3F);
  if index < 56 then padLen := 56 - index
else
padLen := 120 - index;
  MD5Update(Context, PByteArray(@PADDING), padLen);
  MD5Update(Context, PByteArray(@Bits), 8);
  MD5Encode(PByteArray(@Digest), PUINT4Array(@Context.state),
   16);
  MD5_memset(PByteArray(@Context), 0, SizeOf(Context));
end;
 
 
function MD5DigestToStr(const Digest:
TMD5Digest): string;
var
  i: Integer;
begin
  Result := '';
  for i := 0 to 15 do Result := Result + IntToHex(Digest.v[i],
   2);
end;
 
 
function MD5String(const S: string): TMD5Digest;
begin
  Result := MD5Buffer(PChar(S)^, Length(S));
end;
 
 
function MD5File(const FileName: string): TMD5Digest;
var
  F: TFileStream;
begin
  F := TFileStream.Create(FileName, fmOpenRead);
  try
     Result := MD5Stream(F);
  finally
     F.Free;
  end;
end;
 
 
function MD5Stream(const Stream: TStream): TMD5Digest;
var
  Context: TMD5Context;
Buffer: array[0..4095] of Byte;
Size: Integer;
ReadBytes: Integer;
TotalBytes: Integer;
SavePos: Integer;
begin
  MD5Init(Context);
  Size := Stream.Size;
  SavePos := Stream.Position;
  TotalBytes := 0;
  try
     Stream.Seek(0, soFromBeginning);
   repeat
      ReadBytes := Stream.Read(Buffer, SizeOf(Buffer));
      Inc(TotalBytes, ReadBytes);
      MD5Update(Context, @Buffer, ReadBytes);
   until (ReadBytes = 0) or (TotalBytes = Size);
  finally
     Stream.Seek(SavePos, soFromBeginning);
  end;
  MD5Final(Result, Context);
end;
 
 
function MD5Buffer(const Buffer;
Size: Integer): TMD5Digest;
var
  Context: TMD5Context;
begin
  MD5Init(Context);
  MD5Update(Context, PByteArray(@Buffer), Size);
  MD5Final(Result, Context);
end;
 
 
function MD5DigestCompare(const Digest1,
Digest2: TMD5Digest): Boolean;
begin
  Result := False;
  if Digest1.A <> Digest2.A then Exit;
  if Digest1.B <> Digest2.B then Exit;
  if Digest1.C <> Digest2.C then Exit;
  if Digest1.D <> Digest2.D then Exit;
  Result := True;
end;
 
end.