(*

 * Hedgewars, a worms-like game

 * Copyright (c) 2004, 2005 Andrey Korotaev <unC0Rr@gmail.com>

 *

 * Distributed under the terms of the BSD-modified licence:

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * with the Software without restriction, including without limitation the

 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or

 * sell copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * 1. Redistributions of source code must retain the above copyright notice,

 *    this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright notice,

 *    this list of conditions and the following disclaimer in the documentation

 *    and/or other materials provided with the distribution.

 * 3. The name of the author may not be used to endorse or promote products

 *    derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED

 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF

 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO

 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;

 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,

 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR

 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF

 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 *)

unit uSHA;

interface

type TSHA1Context = packed record

                    H: array[0..4] of LongWord;

                    Length, CurrLength: Int64;

                    Buf: array[0..63] of byte;

                    end;

     TSHA1Digest = record

                   case byte of

                        0: (LongWords: array[0.. 4] of LongWord);

                        1: (    Words: array[0.. 9] of     Word);

                        2: (    Bytes: array[0..19] of     Byte)

                   end;

procedure SHA1Init(var Context: TSHA1Context);

procedure SHA1Update(var Context: TSHA1Context; Buf: Pointer; Length: LongWord);

function  SHA1Final(Context: TSHA1Context): TSHA1Digest;

implementation

function rol(x: LongWord; y: Byte): LongWord;

begin

  Result:= (X shl y) or (X shr (32 - y))

end;

function Ft(t, b, c, d: LongWord): LongWord;

begin

case t of

      0..19: Result := (b and c) or ((not b) and d);

     20..39: Result :=  b xor c xor d;

     40..59: Result := (b and c) or (b and d) or (c and d);

     else    Result :=  b xor c xor d;

  end;

end;

function Kt(t: Byte): LongWord;

begin

  case t of

     0..19: Result := $5A827999;

    20..39: Result := $6ED9EBA1;

    40..59: Result := $8F1BBCDC;

  else

    Result := $CA62C1D6

  end;

end;

procedure SHA1Hash(var Context: TSHA1Context);

var S: array[0..4 ] of LongWord;

    W: array[0..79] of LongWord;

    i, t: LongWord;

begin

move(Context.H, S, sizeof(S));

for i := 16 to 79 do

    W[i] := rol(W[i - 3] xor W[i - 8] xor W[i - 14] xor W[i - 16], 1);

for i := 0 to 79 do

    begin

    t:= rol(S[0], 5) + Ft(i, S[1], S[2], S[3]) + S[4] + W[i] + Kt(i);

    S[4]:= S[3];

    S[3]:= S[2];

    S[2]:= rol(S[1], 30);

    S[1]:= S[0];

    S[0]:= t

    end;

for i := 0 to 4 do

    Context.H[i]:= Context.H[i] + S[i]

end;

procedure SHA1Init(var Context: TSHA1Context);

begin

  with Context do

       begin

       Length    := 0;

       CurrLength:= 0;

       H[0]:= $67452301;

       H[1]:= $EFCDAB89;

       H[2]:= $98BADCFE;

       H[3]:= $10325476;

       H[4]:= $C3D2E1F0

  end

end;

procedure SHA1Update(var Context: TSHA1Context; Buf: Pointer; Length: LongWord);

var i: integer;

begin

    begin

    inc(Context.CurrLength);

    if Context.CurrLength=64 then

       begin

       SHA1Hash(Context);

       inc(Context.Length, 512);

       Context.CurrLength:=0

       end

    end

end;

function  SHA1Final(Context: TSHA1Context): TSHA1Digest;

var i: LongWord;

begin

Context.Length:= Context.Length + Context.CurrLength shl 3;

Context.Buf[Context.CurrLength]:= $80;

inc(Context.CurrLength);

if Context.CurrLength>56 then

   begin

   FillChar(Context.Buf[Context.CurrLength],64-Context.CurrLength,0);

   Context.CurrLength:= 64;

   SHA1Hash(Context);

   Context.CurrLength:=0

   end;

FillChar(Context.Buf[Context.CurrLength],56-Context.CurrLength,0);

for i:= 56 to 63 do

    Context.Buf[i] := (Context.Length shr ((63 - i) * 8)) and $FF;

SHA1Hash(Context);

move(Context.H, Result, sizeof(TSHA1Digest));

FillChar(Context, sizeof(Context), 0)

end;

end.