diff -r 8d0783d2a0ff -r a1d2180fef42 hedgewars/adler32.pas
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hedgewars/adler32.pas	Sun Jun 20 22:35:10 2010 -0400
@@ -0,0 +1,152 @@
+unit Adler32;
+
+{ZLib - Adler32 checksum function}
+
+
+interface
+
+(*************************************************************************
+
+ DESCRIPTION     :  ZLib - Adler32 checksum function
+
+ REQUIREMENTS    :  TP5-7, D1-D7/D9-D10/D12, FPC, VP
+
+ EXTERNAL DATA   :  ---
+
+ MEMORY USAGE    :  ---
+
+ DISPLAY MODE    :  ---
+
+ REFERENCES      :  RFC 1950 (http://tools.ietf.org/html/rfc1950)
+
+
+ Version  Date      Author      Modification
+ -------  --------  -------     ------------------------------------------
+ 0.10     30.08.03  W.Ehrhardt  Initial version based on MD5 layout
+ 2.10     30.08.03  we          Common vers., XL versions for Win32
+ 2.20     27.09.03  we          FPC/go32v2
+ 2.30     05.10.03  we          STD.INC, TP5.0
+ 2.40     10.10.03  we          common version, english comments
+ 3.00     01.12.03  we          Common version 3.0
+ 3.01     22.05.05  we          Adler32UpdateXL (i,n: integer)
+ 3.02     17.12.05  we          Force $I- in Adler32File
+ 3.03     07.08.06  we          $ifdef BIT32: (const fname: shortstring...)
+ 3.04     10.02.07  we          Adler32File: no eof, XL and filemode via $ifdef
+ 3.05     04.07.07  we          BASM16: speed-up factor 15
+ 3.06     12.11.08  we          uses BTypes, Ptr2Inc and/or Str255
+ 3.07     25.04.09  we          updated RFC URL(s)
+ 3.08     19.07.09  we          D12 fix: assign with typecast string(fname)
+**************************************************************************)
+
+(*-------------------------------------------------------------------------
+ (C) Copyright 2002-2009 Wolfgang Ehrhardt
+
+ This software is provided 'as-is', without any express or implied warranty.
+ In no event will the authors be held liable for any damages arising from
+ the use of this software.
+
+ Permission is granted to anyone to use this software for any purpose,
+ including commercial applications, and to alter it and redistribute it
+ freely, subject to the following restrictions:
+
+ 1. The origin of this software must not be misrepresented; you must not
+    claim that you wrote the original software. If you use this software in
+    a product, an acknowledgment in the product documentation would be
+    appreciated but is not required.
+
+ 2. Altered source versions must be plainly marked as such, and must not be
+    misrepresented as being the original software.
+
+ 3. This notice may not be removed or altered from any source distribution.
+----------------------------------------------------------------------------*)
+
+(*
+As per the license above, noting that this implementation of adler32 was stripped of everything we didn't need.
+That means no btypes, file loading, and the assembly version disabled.
+*)
+
+procedure Adler32Update(var adler: longint; Msg: pointer; Len: longint);
+
+implementation
+
+(*
+$ifdef BASM16
+
+procedure Adler32Update(var adler: longint; Msg: pointer; Len: longint);
+  //-update Adler32 with Msg data
+const
+  BASE = 65521; // max. prime < 65536 
+  NMAX =  5552; // max. n with 255n(n+1)/2 + (n+1)(BASE-1) < 2^32
+type
+  LH    = packed record
+            L,H: word;
+          end;
+var
+  s1,s2: longint;
+  n: integer;
+begin
+  s1 := LH(adler).L;
+  s2 := LH(adler).H;
+  while Len > 0 do begin
+    if Len<NMAX then n := Len else n := NMAX;
+    //BASM increases speed from about 52 cyc/byte to about 3.7 cyc/byte
+    asm
+                    mov  cx,[n]
+            db $66; mov  ax,word ptr [s1]
+            db $66; mov  di,word ptr [s2]
+                    les  si,[msg]
+      @@1:  db $66, $26, $0f, $b6, $1c      // movzx ebx,es:[si]
+                    inc  si
+            db $66; add  ax,bx              // inc(s1, pByte(Msg)^)
+            db $66; add  di,ax              // inc(s2, s1
+                    dec  cx
+                    jnz  @@1
+            db $66; sub  cx,cx
+                    mov  cx,BASE
+            db $66; sub  dx,dx
+            db $66; div  cx
+            db $66; mov  word ptr [s1],dx   // s1 := s1 mod BASE
+            db $66; sub  dx,dx
+            db $66; mov  ax,di
+            db $66; div  cx
+            db $66; mov  word ptr [s2],dx   // s2 := s2 mod BASE
+                    mov  word ptr [msg],si  // save offset for next chunk
+    end;
+    dec(len, n);
+  end;
+  LH(adler).L := word(s1);
+  LH(adler).H := word(s2);
+end;
+*)
+
+procedure Adler32Update(var adler: longint; Msg: pointer; Len: longint);
+  {-update Adler32 with Msg data}
+const
+  BASE = 65521; {max. prime < 65536 }
+  NMAX =  3854; {max. n with 255n(n+1)/2 + (n+1)(BASE-1) < 2^31}
+type
+  LH    = packed record
+            L,H: word;
+          end;
+var
+  s1,s2: longint;
+  i,n: integer;
+begin
+  s1 := LH(adler).L;
+  s2 := LH(adler).H;
+  while Len > 0 do begin
+    if Len<NMAX then n := Len else n := NMAX;
+    for i:=1 to n do begin
+      inc(s1, pByte(Msg)^);
+      inc(Msg);
+      inc(s2, s1);
+    end;
+    s1 := s1 mod BASE;
+    s2 := s2 mod BASE;
+    dec(len, n);
+  end;
+  LH(adler).L := word(s1);
+  LH(adler).H := word(s2);
+end;
+
+end.