freepascal.compiler/packages/unzip/src/unzip51g.pp

{
}
UNIT Unzip51g;
{
Unzips deflated, imploded, shrunk and stored files
  ** COMPATIBLE WITH
        * Turbo Pascal v7.x     (DOS)
        * Borland Pascal v7.x   (Dos, DPMI, and Windows)
        * Delphi v1.x
        * Delphi v2.x
        * Delphi v3.x
        * Virtual Pascal v2.0   (OS/2, Win32)
        * Free Pascal Compiler  (DOS, OS/2, Win32, Linux, FreeBSD, NetBSD)
}

{
  Original version (1.x): Christian Ghisler
   C code by info-zip group, translated to pascal by Christian Ghisler
   based on unz51g.zip;
   Special thanks go to Mark Adler,who wrote the main inflate and
   explode code, and did NOT copyright it!!!

 v2.00: March 1998: Dr Abimbola Olowofoyeku (The African Chief)
        Homepage: http://ourworld.compuserve.com/homepages/African_Chief
   * modified to compile for Delphi v2.x and Delphi v3.x

 v2.01: April 1998: Dr Abimbola Olowofoyeku (The African Chief)
   * source files merged into a single source (this) file
   * several high level functions added - i.e.,
              FileUnzip()
              FileUnzipEx()
              ViewZip()
              UnzipSize()
              SetUnzipReportProc()
              SetUnzipQuestionProc()
              ChfUnzip_Init()
   * callbacks added
   * modified to support Virtual Pascal v2.0 (Win32)
   * Delphi component added (chfunzip.pas)
 v2.01a: December 1998: Tomas Hajny, [email protected]
   * extended to support other 32-bit compilers/platforms (OS/2, GO32, ...);
     search for (* TH ... *)
 v2.01b: December 1998: Peter Vreman
   * modifications needed for Linux
}

INTERFACE

{$IFDEF FPC}
 {$DEFINE BIT32}
{$ENDIF}

{$IFDEF OS2}
 {$DEFINE BIT32}
{$ENDIF}

{$IFDEF WIN32}
 {$DEFINE BIT32}
{$ENDIF}

{$IFNDEF FPC}
  {$F+}
{$ENDIF}

{$R-}         {No range checking}

USES
  strings,
  dos,
  ziptypes;

{**********************************************************************}
{**********************************************************************}
{****** HIGH LEVEL FUNCTIONS: BY THE AFRICAN CHIEF ********************}
{**********************************************************************}
{**********************************************************************}
FUNCTION FileUnzip
( SourceZipFile, TargetDirectory, FileSpecs : pChar;
 Report : UnzipReportProc;Question : UnzipQuestionProc ) : integer;

{
high level unzip
usage:
SourceZipFile: source zip file;
TargetDirectory: target directory
FileSpecs: "*.*", etc.
Report: Report callback or Nil;
Question: Question callback (for confirmation of whether to replace existing
          files) or Nil;

* REFER to ZIPTYPES.PAS for information on callback functions

e.g.,
   Count := FileUnzip('test.zip', 'c:\temp', '*.*', MyReportProc, Nil);

}

FUNCTION FileUnzipEx ( SourceZipFile, TargetDirectory, FileSpecs : pChar ) : integer;
{
high level unzip with no callback parameters;
passes ZipReport & ZipQuestion internally, so you
can use SetZipReportProc and SetZipQuestionProc before calling this;

e.g.,
   Count := FileUnzipEx('test.zip', 'c:\temp', '*.*');
}

FUNCTION ViewZip ( SourceZipFile, FileSpecs : pChar; Report : UnzipReportProc ) : integer;
{
view contents of zip file
usage:
SourceZipFile: source zip file;
FileSpecs: "*.*", etc.
Report: callback procedure to process the reported contents of ZIP file;

* REFER to ZIPTYPES.PAS for information on callback functions

e.g.,
  ViewZip('test.zip', '*.*', MyReportProc);
}

FUNCTION  SetUnZipReportProc ( aProc : UnzipReportProc ) : Pointer;
{
sets the internal unzip report procedure to aproc
Returns: pointer to the original report procedure
(return value should normally be ignored)

e.g.,
   SetUnZipReportProc(MyReportProc);
}

FUNCTION  SetUnZipQuestionProc ( aProc : UnzipQuestionProc ) : Pointer;
{
sets the internal unzip question procedure to aproc
Returns: pointer to the original "question" procedure
(return value should normally be ignored)

e.g.,
SetUnZipQuestionProc(QueryFileExistProc);
}

FUNCTION UnzipSize ( SourceZipFile : pChar;VAR Compressed : Longint ) : longint;
{ uncompressed and compressed zip size
 usage:
 SourceZipFile  = the zip file
 Compressed     = the compressed size of the files in the archive
 Returns:         the uncompressed size of the ZIP archive

e.g.,
  Var
  Size,CSize:longint;
  begin
     Size := UnzipSize('test.zip', CSize);
  end;
}

PROCEDURE ChfUnzip_Init;
{
initialise or reinitialise the shared data: !!! use with care !!!
}

FUNCTION SetNoRecurseDirs ( DontRecurse : Boolean ) : Boolean;
{
determine whether the UNZIP function should recreate
the subdirectory structure;
 DontRecurse = TRUE :  don't recurse
 DontRecurse = FALSE : recurse (default)
}

{**********************************************************************}
{**********************************************************************}
{************ LOW LEVEL FUNCTIONS: BY CHRISTIAN GHISLER ***************}
{**********************************************************************}
{**********************************************************************}
FUNCTION GetSupportedMethods : longint;
{Checks which pack methods are supported by the dll}
{bit 8=1 -> Format 8 supported, etc.}

FUNCTION UnzipFile ( in_name : pchar;out_name : pchar;offset : longint;hFileAction : word;cm_index : integer ) : integer;
{usage:
 in_name:      name of zip file with full path
 out_name:     desired name for out file
 offset:       header position of desired file in zipfile
 hFileAction:  handle to dialog box showing advance of decompression (optional)
 cm_index:     notification code sent in a wm_command message to the dialog
               to update percent-bar
 Return value: one of the above unzip_xxx codes

 Example for handling the cm_index message in a progress dialog:

 unzipfile(......,cm_showpercent);

 ...

 procedure TFileActionDialog.wmcommand(var msg:tmessage);
 var ppercent:^word;
 begin
   TDialog.WMCommand(msg);
   if msg.wparam=cm_showpercent then begin
     ppercent:=pointer(lparam);
     if ppercent<>nil then begin
       if (ppercent^>=0) and (ppercent^<=100) then
         SetProgressBar(ppercent^);
       if UserPressedAbort then
         ppercent^:=$ffff
       else
         ppercent^:=0;
       end;
     end;
   end;
 end;
}

FUNCTION  GetFirstInZip ( zipfilename : pchar;VAR zprec : tZipRec ) : integer;
{
 Get first entry from ZIP file
 e.g.,
   rc:=GetFirstInZip('test.zip', myZipRec);
}

FUNCTION  GetNextInZip ( VAR Zprec : tZiprec ) : integer;
{
  Get next entry from ZIP file

 e.g.,
   rc:=GetNextInZip(myZipRec);
}

FUNCTION  IsZip ( filename : pchar ) : boolean;
{
  VERY simple test for zip file

  e.g.,
   ItsaZipFile := IsZip('test.zip');
}

PROCEDURE CloseZipFile ( VAR Zprec : tZiprec );  {Only free buffer, file only open in Getfirstinzip}
{
  free ZIP buffers

  e.g.,
  CloseZipFile(myZipRec);
}

IMPLEMENTATION

VAR
ZipReport : UnzipReportProc;        {Global Status Report Callback}
ZipQuestion : UnzipQuestionProc;    {Global "Question" Callback}
ZipRec : TReportRec;                {Global ZIP record for callbacks}
NoRecurseDirs : Boolean;              {Global Recurse variable}

{*************************************************************************}
{$ifdef Delphi}
PROCEDURE SetCurDir ( p : pChar );
BEGIN
   Chdir ( strpas ( p ) );
END;

FUNCTION DosError : integer;  {Delphi DosError kludge}
BEGIN
   Result := Ioresult;
END;

FUNCTION SetFTime ( VAR f : File; CONST l : longint ) : integer;
BEGIN
   {$ifdef Win32}Result := {$endif}FileSetDate ( TFileRec ( f ) .Handle, l );
END;

PROCEDURE CreateDir ( p : pchar );
BEGIN
  mkdir ( strpas ( p ) );
END;

{/////////////////////////////////////////////////////////}
{$endif Delphi}

{.$I z_global.pas}  {global constants, types and variables}
{Include file for unzip.pas: global constants, types and variables}

{C code by info-zip group, translated to pascal by Christian Ghisler}
{based on unz51g.zip}

CONST   {Error codes returned by huft_build}
  huft_complete  = 0;   {Complete tree}
  huft_incomplete = 1;   {Incomplete tree <- sufficient in some cases!}
  huft_error     = 2;   {bad tree constructed}
  huft_outofmem  = 3;   {not enough memory}
(* TH - use of the new BIT32 conditional (was WIN32 only previously) *)
  MaxMax = {$ifdef BIT32}256 * 1024    {BIT32 =  256kb buffer}
           {$else}Maxint -1{$endif}; {16-bit = 32kb buffer}

CONST wsize = $8000;          {Size of sliding dictionary}
      INBUFSIZ = 1024 * 4;      {Size of input buffer}

CONST lbits : integer = 9;
      dbits : integer = 6;

CONST b_max = 16;
      n_max = 288;
      BMAX = 16;

TYPE push = ^ush;
     ush = word;
     pbyte = ^byte;
     pushlist = ^ushlist;
     ushlist = ARRAY [ 0..maxmax ] of ush;  {only pseudo-size!!}
     pword = ^word;
     pwordarr = ^twordarr;
     twordarr = ARRAY [ 0..maxmax ] of word;
     iobuf = ARRAY [ 0..inbufsiz -1 ] of byte;

TYPE pphuft = ^phuft;
     phuft = ^huft;
     phuftlist = ^huftlist;
     huft = PACKED RECORD
       e,             {# of extra bits}
       b : byte;        {# of bits in code}
       v_n : ush;
       v_t : phuftlist; {Linked List}
     END;
     huftlist = ARRAY [ 0..8190 ] of huft;

TYPE li = PACKED RECORD
       lo, hi : word;
     END;

{pkzip header in front of every file in archive}
TYPE
  plocalheader = ^tlocalheader;
  tlocalheader = PACKED RECORD
    signature : ARRAY [ 0..3 ] of char;  {'PK'#1#2}
    extract_ver,
    bit_flag,
    zip_type : word;
    file_timedate : longint;
    crc_32,
    compress_size,
    uncompress_size : longint;
    filename_len,
    extra_field_len : word;
  END;

VAR slide : pchar;            {Sliding dictionary for unzipping}
    inbuf : iobuf;            {input buffer}
    inpos, readpos : integer;  {position in input buffer, position read from file}

VAR w : longint;                 {Current Position in slide}
    b : longint;              {Bit Buffer}
    k : byte;                 {Bits in bit buffer}
    infile,                 {handle to zipfile}
    outfile : file;           {handle to extracted file}
    compsize,               {comressed size of file}
    reachedsize,            {number of bytes read from zipfile}
    uncompsize : longint;     {uncompressed size of file}
    crc32val : cardinal;       {crc calculated from data}
    hufttype : word;          {coding type=bit_flag from header}
    totalabort,             {User pressed abort button, set in showpercent!}
    zipeof : boolean;         {read over end of zip section for this file}
    inuse : boolean;          {is unit already in use -> don't call it again!!!}

(***************************************************************************)
{.$I z_tables.pas}  {Tables for bit masking, huffman codes and CRC checking}

{include file for unzip.pas: Tables for bit masking, huffman codes and CRC checking}

{C code by info-zip group, translated to Pascal by Christian Ghisler}
{based on unz51g.zip}

{b and mask_bits[i] gets lower i bits out of i}
CONST mask_bits : ARRAY [ 0..16 ] of word =
   ( $0000,
    $0001, $0003, $0007, $000f, $001f, $003f, $007f, $00ff,
    $01ff, $03ff, $07ff, $0fff, $1fff, $3fff, $7fff, $ffff );

{ Tables for deflate from PKZIP's appnote.txt. }

CONST border : ARRAY [ 0..18 ] of byte =   { Order of the bit length code lengths }
        ( 16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15 );
CONST cplens : ARRAY [ 0..30 ] of word =    { Copy lengths for literal codes 257..285 }
        ( 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31,
        35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258, 0, 0 );
        { note: see note #13 above about the 258 in this list.}
CONST cplext : ARRAY [ 0..30 ] of word =    { Extra bits for literal codes 257..285 }
        ( 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2,
        3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0, 99, 99 ); { 99==invalid }
CONST cpdist : ARRAY [ 0..29 ] of word =     { Copy offsets for distance codes 0..29 }
        ( 1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193,
        257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145,
        8193, 12289, 16385, 24577 );
CONST cpdext : ARRAY [ 0..29 ] of word =    { Extra bits for distance codes }
        ( 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6,
        7, 7, 8, 8, 9, 9, 10, 10, 11, 11,
        12, 12, 13, 13 );

{ Tables for explode }

CONST cplen2 : ARRAY [ 0..63 ] of word = ( 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,
        18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34,
        35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,
        52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65 );
CONST cplen3 : ARRAY [ 0..63 ] of word = ( 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
        19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35,
        36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52,
        53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66 );
CONST extra : ARRAY [ 0..63 ] of word = ( 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,
        8 );
CONST cpdist4 : ARRAY [ 0..63 ] of word = ( 1, 65, 129, 193, 257, 321, 385, 449, 513, 577, 641, 705,
        769, 833, 897, 961, 1025, 1089, 1153, 1217, 1281, 1345, 1409, 1473,
        1537, 1601, 1665, 1729, 1793, 1857, 1921, 1985, 2049, 2113, 2177,
        2241, 2305, 2369, 2433, 2497, 2561, 2625, 2689, 2753, 2817, 2881,
        2945, 3009, 3073, 3137, 3201, 3265, 3329, 3393, 3457, 3521, 3585,
        3649, 3713, 3777, 3841, 3905, 3969, 4033 );
CONST cpdist8 : ARRAY [ 0..63 ] of word = ( 1, 129, 257, 385, 513, 641, 769, 897, 1025, 1153, 1281,
        1409, 1537, 1665, 1793, 1921, 2049, 2177, 2305, 2433, 2561, 2689,
        2817, 2945, 3073, 3201, 3329, 3457, 3585, 3713, 3841, 3969, 4097,
        4225, 4353, 4481, 4609, 4737, 4865, 4993, 5121, 5249, 5377, 5505,
        5633, 5761, 5889, 6017, 6145, 6273, 6401, 6529, 6657, 6785, 6913,
        7041, 7169, 7297, 7425, 7553, 7681, 7809, 7937, 8065 );

{************************************ CRC-Calculation ************************************}

CONST crc_32_tab : ARRAY [ 0..255 ] of cardinal =
(
   $00000000, $77073096, $ee0e612c, $990951ba, $076dc419,
   $706af48f, $e963a535, $9e6495a3, $0edb8832, $79dcb8a4,
   $e0d5e91e, $97d2d988, $09b64c2b, $7eb17cbd, $e7b82d07,
   $90bf1d91, $1db71064, $6ab020f2, $f3b97148, $84be41de,
   $1adad47d, $6ddde4eb, $f4d4b551, $83d385c7, $136c9856,
   $646ba8c0, $fd62f97a, $8a65c9ec, $14015c4f, $63066cd9,
   $fa0f3d63, $8d080df5, $3b6e20c8, $4c69105e, $d56041e4,
   $a2677172, $3c03e4d1, $4b04d447, $d20d85fd, $a50ab56b,
   $35b5a8fa, $42b2986c, $dbbbc9d6, $acbcf940, $32d86ce3,
   $45df5c75, $dcd60dcf, $abd13d59, $26d930ac, $51de003a,
   $c8d75180, $bfd06116, $21b4f4b5, $56b3c423, $cfba9599,
   $b8bda50f, $2802b89e, $5f058808, $c60cd9b2, $b10be924,
   $2f6f7c87, $58684c11, $c1611dab, $b6662d3d, $76dc4190,
   $01db7106, $98d220bc, $efd5102a, $71b18589, $06b6b51f,
   $9fbfe4a5, $e8b8d433, $7807c9a2, $0f00f934, $9609a88e,
   $e10e9818, $7f6a0dbb, $086d3d2d, $91646c97, $e6635c01,
   $6b6b51f4, $1c6c6162, $856530d8, $f262004e, $6c0695ed,
   $1b01a57b, $8208f4c1, $f50fc457, $65b0d9c6, $12b7e950,
   $8bbeb8ea, $fcb9887c, $62dd1ddf, $15da2d49, $8cd37cf3,
   $fbd44c65, $4db26158, $3ab551ce, $a3bc0074, $d4bb30e2,
   $4adfa541, $3dd895d7, $a4d1c46d, $d3d6f4fb, $4369e96a,
   $346ed9fc, $ad678846, $da60b8d0, $44042d73, $33031de5,
   $aa0a4c5f, $dd0d7cc9, $5005713c, $270241aa, $be0b1010,
   $c90c2086, $5768b525, $206f85b3, $b966d409, $ce61e49f,
   $5edef90e, $29d9c998, $b0d09822, $c7d7a8b4, $59b33d17,
   $2eb40d81, $b7bd5c3b, $c0ba6cad, $edb88320, $9abfb3b6,
   $03b6e20c, $74b1d29a, $ead54739, $9dd277af, $04db2615,
   $73dc1683, $e3630b12, $94643b84, $0d6d6a3e, $7a6a5aa8,
   $e40ecf0b, $9309ff9d, $0a00ae27, $7d079eb1, $f00f9344,
   $8708a3d2, $1e01f268, $6906c2fe, $f762575d, $806567cb,
   $196c3671, $6e6b06e7, $fed41b76, $89d32be0, $10da7a5a,
   $67dd4acc, $f9b9df6f, $8ebeeff9, $17b7be43, $60b08ed5,
   $d6d6a3e8, $a1d1937e, $38d8c2c4, $4fdff252, $d1bb67f1,
   $a6bc5767, $3fb506dd, $48b2364b, $d80d2bda, $af0a1b4c,
   $36034af6, $41047a60, $df60efc3, $a867df55, $316e8eef,
   $4669be79, $cb61b38c, $bc66831a, $256fd2a0, $5268e236,
   $cc0c7795, $bb0b4703, $220216b9, $5505262f, $c5ba3bbe,
   $b2bd0b28, $2bb45a92, $5cb36a04, $c2d7ffa7, $b5d0cf31,
   $2cd99e8b, $5bdeae1d, $9b64c2b0, $ec63f226, $756aa39c,
   $026d930a, $9c0906a9, $eb0e363f, $72076785, $05005713,
   $95bf4a82, $e2b87a14, $7bb12bae, $0cb61b38, $92d28e9b,
   $e5d5be0d, $7cdcefb7, $0bdbdf21, $86d3d2d4, $f1d4e242,
   $68ddb3f8, $1fda836e, $81be16cd, $f6b9265b, $6fb077e1,
   $18b74777, $88085ae6, $ff0f6a70, $66063bca, $11010b5c,
   $8f659eff, $f862ae69, $616bffd3, $166ccf45, $a00ae278,
   $d70dd2ee, $4e048354, $3903b3c2, $a7672661, $d06016f7,
   $4969474d, $3e6e77db, $aed16a4a, $d9d65adc, $40df0b66,
   $37d83bf0, $a9bcae53, $debb9ec5, $47b2cf7f, $30b5ffe9,
   $bdbdf21c, $cabac28a, $53b39330, $24b4a3a6, $bad03605,
   $cdd70693, $54de5729, $23d967bf, $b3667a2e, $c4614ab8,
   $5d681b02, $2a6f2b94, $b40bbe37, $c30c8ea1, $5a05df1b,
   $2d02ef8d ); { end crc_32_tab[] }
(***************************************************************************)
{.$I z_generl.pas}  {General functions used by both inflate and explode}
{include for unzip.pas: General functions used by both inflate and explode}

{C code by info-zip group, translated to Pascal by Christian Ghisler}
{based on unz51g.zip}

{*********************************** CRC Checking ********************************}

PROCEDURE UpdateCRC ( VAR s : iobuf;len : word );
VAR i : word;
BEGIN
{$ifndef assembler}
 If len = 0 then exit;
 FOR i := 0 TO Pred ( len ) DO BEGIN
    { update running CRC calculation with contents of a buffer }
    crc32val := crc_32_tab [  ( byte ( crc32val ) XOR s [ i ] ) AND $ff ] XOR ( crc32val SHR 8 );
  END;
{$else}
  ASM
    les di, s
    mov ax, li.lo ( crc32val )
    mov dx, li.hi ( crc32val )
    mov si, offset crc_32_tab      {Segment remains DS!!!}
    mov cx, len
    OR cx, cx
    jz @finished
@again :
    mov bl, al           {byte(crcval)}
    mov al, ah           {shift DX:AX by 8 bits to the right}
    mov ah, dl
    mov dl, dh
    XOR dh, dh

    XOR bh, bh
    XOR bl, es : [ di ]  {xor s^}
    inc di
    SHL bx, 1            {Offset: Index*4}
    SHL bx, 1
    XOR ax, [ si + bx ]
    XOR dx, [ si + bx + 2 ]
    dec cx
    jnz @again
@finished :
    mov li.lo ( crc32val ), ax
    mov li.hi ( crc32val ), dx
  END;
{$endif}
END;

{************************** fill inbuf from infile *********************}

PROCEDURE readbuf;
BEGIN
  IF reachedsize > compsize + 2 THEN BEGIN {+2: last code is smaller than requested!}
    readpos := sizeof ( inbuf ); {Simulates reading -> no blocking}
    zipeof := TRUE
  END ELSE BEGIN
    {$I-}
    blockread ( infile, inbuf, sizeof ( inbuf ), readpos );
    {$I+}
    IF ( ioresult <> 0 ) OR ( readpos = 0 ) THEN BEGIN  {readpos=0: kein Fehler gemeldet!!!}
      readpos := sizeof ( inbuf ); {Simulates reading -> CRC error}
      zipeof := TRUE;
    END;
    inc ( reachedsize, readpos );
    dec ( readpos );    {Reason: index of inbuf starts at 0}
  END;
  inpos := 0;
END;

{**** read byte, only used by explode ****}

PROCEDURE READBYTE ( VAR bt : byte );
BEGIN
  IF inpos > readpos THEN readbuf;
  bt := inbuf [ inpos ];
  inc ( inpos );
END;

{*********** read at least n bits into the global variable b *************}

PROCEDURE NEEDBITS ( n : byte );
VAR nb : longint;
BEGIN
{$ifndef assembler}
  WHILE k < n DO BEGIN
    IF inpos > readpos THEN readbuf;
    nb := inbuf [ inpos ];
    inc ( inpos );
    b := b OR nb SHL k;
    inc ( k, 8 );
  END;
{$else}
  ASM
    mov si, offset inbuf
    mov ch, n
    mov cl, k
    mov bx, inpos    {bx=inpos}
@again :
    cmp cl, ch
    JAE @finished   {k>=n -> finished}
    cmp bx, readpos
    jg @readbuf
@fullbuf :
    mov al, [ si + bx ]  {dx:ax=nb}
    XOR ah, ah
    XOR dx, dx
    cmp cl, 8      {cl>=8 -> shift into DX or directly by 1 byte}
    JAE @bigger8
    SHL ax, cl     {Normal shifting!}
    jmp @continue
@bigger8 :
    mov di, cx     {save cx}
    mov ah, al     {shift by 8}
    XOR al, al
    sub cl, 8      {8 bits shifted}
@rotate :
    OR cl, cl
    jz @continue1 {all shifted -> finished}
    SHL ah, 1      {al ist empty!}
    rcl dx, 1
    dec cl
    jmp @rotate
@continue1 :
    mov cx, di
@continue :
    OR li.hi ( b ), dx {b=b or nb shl k}
    OR li.lo ( b ), ax
    inc bx         {inpos}
    add cl, 8       {inc k by 8 Bits}
    jmp @again

@readbuf :
    push si
    push cx
    call readbuf   {readbuf not critical, called only every 2000 bytes}
    pop cx
    pop si
    mov bx, inpos   {New inpos}
    jmp @fullbuf

@finished :
    mov k, cl
    mov inpos, bx
  END;
{$endif}
END;

{***************** dump n bits no longer needed from global variable b *************}

PROCEDURE DUMPBITS ( n : byte );
BEGIN
{$ifndef assembler}
  b := b SHR n;
  k := k -n;
{$else}
  ASM
    mov cl, n
    mov ax, li.lo ( b )
    mov dx, li.hi ( b )

    mov ch, cl
    OR ch, ch
    jz @finished
@rotate :
    SHR dx, 1           {Lower Bit in Carry}
    rcr ax, 1
    dec ch
    jnz @rotate
@finished :
    mov li.lo ( b ), ax
    mov li.hi ( b ), dx
    sub k, cl
  END;
{$endif}
END;

{********************* Flush w bytes directly from slide to file ******************}
FUNCTION flush ( w : word ) : boolean;
VAR n : nword;          {True wenn OK}
b : boolean;
BEGIN
  {$I-}
  blockwrite ( outfile, slide [ 0 ], w, n );
  {$I+}
  b := ( n = w ) AND ( ioresult = 0 );  {True-> alles ok}
  UpdateCRC ( iobuf ( pointer ( @slide [ 0 ] ) ^ ), w );
  {--}
{$IFDEF FPC}
  IF ( b = TRUE ) AND Assigned(ZipReport)  {callback report for high level functions}
{$ELSE}
  IF ( b = TRUE ) AND ( @ZipReport <> NIL )  {callback report for high level functions}
{$ENDIF}
  THEN BEGIN
      WITH ZipRec DO BEGIN
           Status := file_unzipping;
           ZipReport ( n, @ZipRec );  {report the actual bytes written}
      END;
  END; {report}
  flush := b;
END;

{******************************* Break string into tokens ****************************}

VAR
  _Token : PChar;

FUNCTION StrTok ( Source : PChar; Token : CHAR ) : PChar;
  VAR P : PChar;
BEGIN
  IF Source <> NIL THEN _Token := Source;
  IF _Token = NIL THEN BEGIN
    strTok := NIL;
    exit
  END;
  P := StrScan ( _Token, Token );
  StrTok := _Token;
  IF P <> NIL THEN BEGIN
    P^ := #0;
    Inc ( P );
  END;
  _Token := P;
END;

(***************************************************************************)
{.$I z_huft.pas}    {Huffman tree generating and destroying}
{include for unzip.pas: Huffman tree generating and destroying}

{C code by info-zip group, translated to Pascal by Christian Ghisler}
{based on unz51g.zip}

{*************** free huffman tables starting with table where t points to ************}

PROCEDURE huft_free ( t : phuftlist );

VAR p, q : phuftlist;
    z : integer;

BEGIN
  p := pointer ( t );
  WHILE p <> NIL DO BEGIN
    dec ( ptrint ( p ), sizeof ( huft ) );
    q := p^ [ 0 ].v_t;
    z := p^ [ 0 ].v_n;   {Size in Bytes, required by TP ***}
    freemem ( p, ( z + 1 ) * sizeof ( huft ) );
    p := q
  END;
END;

{*********** build huffman table from code lengths given by array b^ *******************}

FUNCTION huft_build ( b : pword;n : word;s : word;d, e : pushlist;t : pphuft;VAR m : integer ) : integer;
VAR a : word;                        {counter for codes of length k}
    c : ARRAY [ 0..b_max + 1 ] of word;   {bit length count table}
    f : word;                        {i repeats in table every f entries}
    g,                             {max. code length}
    h : integer;                     {table level}
    i,                             {counter, current code}
    j : word;                        {counter}
    k : integer;                     {number of bits in current code}
    p : pword;                       {pointer into c, b and v}
    q : phuftlist;                   {points to current table}
    r : huft;                        {table entry for structure assignment}
    u : ARRAY [ 0..b_max ] of phuftlist;{table stack}
    v : ARRAY [ 0..n_max ] of word;     {values in order of bit length}
    w : integer;                     {bits before this table}
    x : ARRAY [ 0..b_max + 1 ] of word;   {bit offsets, then code stack}
    l : ARRAY [  -1..b_max + 1 ] of word;  {l[h] bits in table of level h}
    xp : ^word;                      {pointer into x}
    y : integer;                     {number of dummy codes added}
    z : word;                        {number of entries in current table}
    tryagain : boolean;              {bool for loop}
    pt : phuft;                      {for test against bad input}
    el : word;                       {length of eob code=code 256}

BEGIN
  IF n > 256 THEN el := pword ( longint ( b ) + 256 * sizeof ( word ) ) ^
           ELSE el := BMAX;
  {generate counts for each bit length}
  fillchar ( c, sizeof ( c ), #0 );
  p := b; i := n;                      {p points to array of word}
  REPEAT
    IF p^ > b_max THEN BEGIN
      t^ := NIL;
      m := 0;
      huft_build := huft_error;
      exit
    END;
    inc ( c [ p^ ] );
    inc ( ptrint ( p ), sizeof ( word ) );   {point to next item}
    dec ( i );
  UNTIL i = 0;
  IF c [ 0 ] = n THEN BEGIN
    t^ := NIL;
    m := 0;
    huft_build := huft_complete;
    exit
  END;

  {find minimum and maximum length, bound m by those}
  j := 1;
  WHILE ( j <= b_max ) AND ( c [ j ] = 0 ) DO inc ( j );
  k := j;
  IF m < j THEN m := j;
  i := b_max;
  WHILE ( i > 0 ) AND ( c [ i ] = 0 ) DO dec ( i );
  g := i;
  IF m > i THEN m := i;

  {adjust last length count to fill out codes, if needed}
  y := 1 SHL j;
  WHILE j < i DO BEGIN
    y := y -c [ j ];
    IF y < 0 THEN BEGIN
      huft_build := huft_error;
      exit
    END;
    y := y SHL 1;
    inc ( j );
  END;
  dec ( y, c [ i ] );
  IF y < 0 THEN BEGIN
    huft_build := huft_error;
    exit
  END;
  inc ( c [ i ], y );

  {generate starting offsets into the value table for each length}
  x [ 1 ] := 0;
  j := 0;
  p := @c; inc ( ptrint ( p ), sizeof ( word ) );
  xp := @x;inc ( ptrint ( xp ), 2 * sizeof ( word ) );
  dec ( i );
  WHILE i <> 0 DO BEGIN
    inc ( j, p^ );
    xp^ := j;
    inc ( ptrint ( p ), 2 );
    inc ( ptrint ( xp ), 2 );
    dec ( i );
  END;

  {make table of values in order of bit length}
  p := b; i := 0;
  REPEAT
    j := p^;
    inc ( ptrint ( p ), sizeof ( word ) );
    IF j <> 0 THEN BEGIN
      v [ x [ j ] ] := i;
      inc ( x [ j ] );
    END;
    inc ( i );
  UNTIL i >= n;

  {generate huffman codes and for each, make the table entries}
  x [ 0 ] := 0; i := 0;
  p := @v;
  h := -1;
  l [  -1 ] := 0;
  w := 0;
  u [ 0 ] := NIL;
  q := NIL;
  z := 0;

  {go through the bit lengths (k already is bits in shortest code)}
  FOR k := k TO g DO BEGIN
    FOR a := c [ k ] DOWNTO 1 DO BEGIN
      {here i is the huffman code of length k bits for value p^}
      WHILE k > w + l [ h ] DO BEGIN
        inc ( w, l [ h ] ); {Length of tables to this position}
        inc ( h );
        z := g -w;
        IF z > m THEN z := m;
        j := k -w;
        f := 1 SHL j;
        IF f > a + 1 THEN BEGIN
          dec ( f, a + 1 );
          xp := @c [ k ];
          inc ( j );
          tryagain := TRUE;
          WHILE ( j < z ) AND tryagain DO BEGIN
            f := f SHL 1;
            inc ( ptrint ( xp ), sizeof ( word ) );
            IF f <= xp^ THEN tryagain := FALSE
                      ELSE BEGIN
                        dec ( f, xp^ );
                        inc ( j );
                      END;
          END;
        END;
        IF ( w + j > el ) AND ( w < el ) THEN
          j := el -w;       {Make eob code end at table}
        IF w = 0 THEN BEGIN
          j := m;  {*** Fix: main table always m bits!}
        END;
        z := 1 SHL j;
        l [ h ] := j;

        {allocate and link new table}
        getmem ( q, ( z + 1 ) * sizeof ( huft ) );
        IF q = NIL THEN BEGIN
          IF h <> 0 THEN huft_free ( pointer ( u [ 0 ] ) );
          huft_build := huft_outofmem;
          exit
        END;
        fillchar ( q^, ( z + 1 ) * sizeof ( huft ), #0 );
        q^ [ 0 ].v_n := z;  {Size of table, needed in freemem ***}
        t^ := @q^ [ 1 ];     {first item starts at 1}
        t := @q^ [ 0 ].v_t;
        t^ := NIL;
        q := @q^ [ 1 ];   {pointer(longint(q)+sizeof(huft));} {???}
        u [ h ] := q;
        {connect to last table, if there is one}
        IF h <> 0 THEN BEGIN
          x [ h ] := i;
          r.b := l [ h -1 ];
          r.e := 16 + j;
          r.v_t := q;
          j := ( i AND ( ( 1 SHL w ) -1 ) ) SHR ( w -l [ h -1 ] );

          {test against bad input!}
          pt := phuft ( longint ( u [ h -1 ] ) -sizeof ( huft ) );
          IF j > pt^.v_n THEN BEGIN
            huft_free ( pointer ( u [ 0 ] ) );
            huft_build := huft_error;
            exit
          END;

          pt := @u [ h -1 ]^ [ j ];
          pt^ := r;
        END;
      END;

      {set up table entry in r}
      r.b := word ( k -w );
      r.v_t := NIL;   {Unused}   {***********}
      IF longint ( p ) >= longint ( @v [ n ] ) THEN r.e := 99
      ELSE IF p^ < s THEN BEGIN
        IF p^ < 256 THEN r.e := 16 ELSE r.e := 15;
        r.v_n := p^;
        inc ( ptrint ( p ), sizeof ( word ) );
      END ELSE BEGIN
        IF ( d = NIL ) OR ( e = NIL ) THEN BEGIN
          huft_free ( pointer ( u [ 0 ] ) );
          huft_build := huft_error;
          exit
        END;
        r.e := word ( e^ [ p^ -s ] );
        r.v_n := d^ [ p^ -s ];
        inc ( ptrint ( p ), sizeof ( word ) );
      END;

      {fill code like entries with r}
      f := 1 SHL ( k -w );
      j := i SHR w;
      WHILE j < z DO BEGIN
        q^ [ j ] := r;
        inc ( j, f );
      END;

      {backwards increment the k-bit code i}
      j := 1 SHL ( k -1 );
      WHILE ( i AND j ) <> 0 DO BEGIN
        {i:=i^j;}
        i := i XOR j;
        j := j SHR 1;
      END;
      i := i XOR j;

      {backup over finished tables}
      WHILE ( ( i AND ( ( 1 SHL w ) -1 ) ) <> x [ h ] ) DO BEGIN
        dec ( h );
        dec ( w, l [ h ] ); {Size of previous table!}
      END;
    END;
  END;
  IF ( y <> 0 ) AND ( g <> 1 ) THEN huft_build := huft_incomplete
                       ELSE huft_build := huft_complete;
END;

(***************************************************************************)
{.$I z_inflat.pas}  {Inflate deflated file}
{include for unzip.pas: Inflate deflated file}

{C code by info-zip group, translated to Pascal by Christian Ghisler}
{based on unz51g.zip}

FUNCTION inflate_codes ( tl, td : phuftlist;bl, bd : integer ) : integer;
VAR
    n, d, e1,          {length and index for copy}
    ml, md : longint;      {masks for bl and bd bits}
    t : phuft;         {pointer to table entry}
    e : byte;          {table entry flag/number of extra bits}

BEGIN
  { inflate the coded data }
  ml := mask_bits [ bl ];          {precompute masks for speed}
  md := mask_bits [ bd ];
  WHILE NOT ( totalabort OR zipeof ) DO BEGIN
    NEEDBITS ( bl );
    t := @tl^ [ b AND ml ];
    e := t^.e;
    IF e > 16 THEN REPEAT       {then it's a literal}
      IF e = 99 THEN BEGIN
        inflate_codes := unzip_ZipFileErr;
        exit
      END;
      DUMPBITS ( t^.b );
      dec ( e, 16 );
      NEEDBITS ( e );
      t := @t^.v_t^ [ b AND mask_bits [ e ] ];
      e := t^.e;
    UNTIL e <= 16;
    DUMPBITS ( t^.b );
    IF e = 16 THEN BEGIN
      slide [ w ] := char ( t^.v_n );
      inc ( w );
      IF w = WSIZE THEN BEGIN
        IF NOT flush ( w ) THEN BEGIN
          inflate_codes := unzip_WriteErr;
          exit;
        END;
        w := 0
      END;
    END ELSE BEGIN                {it's an EOB or a length}
      IF e = 15 THEN BEGIN {Ende}   {exit if end of block}
        inflate_codes := unzip_Ok;
        exit;
      END;
      NEEDBITS ( e );                 {get length of block to copy}
      n := t^.v_n + ( b AND mask_bits [ e ] );
      DUMPBITS ( e );

      NEEDBITS ( bd );                {decode distance of block to copy}
      t := @td^ [ b AND md ];
      e := t^.e;
      IF e > 16 THEN REPEAT
        IF e = 99 THEN BEGIN
          inflate_codes := unzip_ZipFileErr;
          exit
        END;
        DUMPBITS ( t^.b );
        dec ( e, 16 );
        NEEDBITS ( e );
        t := @t^.v_t^ [ b AND mask_bits [ e ] ];
        e := t^.e;
      UNTIL e <= 16;
      DUMPBITS ( t^.b );
      NEEDBITS ( e );
      d := w -t^.v_n -b AND mask_bits [ e ];
      DUMPBITS ( e );
      {do the copy}
      REPEAT
        d := d AND ( WSIZE -1 );
        IF d > w THEN e1 := WSIZE -d
               ELSE e1 := WSIZE -w;
        IF e1 > n THEN e1 := n;
        dec ( n, e1 );
        IF ( longint(w) -d >= e1 ) THEN BEGIN
          move ( slide [ d ], slide [ w ], e1 );
          inc ( w, e1 );
          inc ( d, e1 );
        END ELSE REPEAT
          slide [ w ] := slide [ d ];
          inc ( w );
          inc ( d );
          dec ( e1 );
        UNTIL ( e1 = 0 );
        IF w = WSIZE THEN BEGIN
          IF NOT flush ( w ) THEN BEGIN
            inflate_codes := unzip_WriteErr;
            exit;
          END;
          w := 0;
        END;
      UNTIL n = 0;
    END;
  END;
  IF totalabort THEN
    inflate_codes := unzip_userabort
  ELSE
    inflate_codes := unzip_readErr;
END;

{**************************** "decompress" stored block **************************}

FUNCTION inflate_stored : integer;
VAR n : word;            {number of bytes in block}

BEGIN
  {go to byte boundary}
  n := k AND 7;
  dumpbits ( n );
  {get the length and its complement}
  NEEDBITS ( 16 );
  n := b AND $ffff;
  DUMPBITS ( 16 );
  NEEDBITS ( 16 );
  IF ( n <> ( NOT b ) AND $ffff ) THEN BEGIN
    inflate_stored := unzip_zipFileErr;
    exit
  END;
  DUMPBITS ( 16 );
  WHILE ( n > 0 ) AND NOT ( totalabort OR zipeof ) DO BEGIN {read and output the compressed data}
    dec ( n );
    NEEDBITS ( 8 );
    slide [ w ] := char ( b );
    inc ( w );
    IF w = WSIZE THEN BEGIN
      IF NOT flush ( w ) THEN BEGIN
        inflate_stored := unzip_WriteErr;
        exit
      END;
      w := 0;
    END;
    DUMPBITS ( 8 );
  END;
  IF totalabort THEN inflate_stored := unzip_UserAbort
    ELSE IF zipeof THEN inflate_stored := unzip_readErr
      ELSE inflate_stored := unzip_Ok;
END;

{**************************** decompress fixed block **************************}

FUNCTION inflate_fixed : integer;
VAR i : integer;               {temporary variable}
    tl,                      {literal/length code table}
    td : phuftlist;                {distance code table}
    bl, bd : integer;           {lookup bits for tl/bd}
    l : ARRAY [ 0..287 ] of word; {length list for huft_build}

BEGIN
  {set up literal table}
  FOR i := 0 TO 143 DO l [ i ] := 8;
  FOR i := 144 TO 255 DO l [ i ] := 9;
  FOR i := 256 TO 279 DO l [ i ] := 7;
  FOR i := 280 TO 287 DO l [ i ] := 8; {make a complete, but wrong code set}
  bl := 7;
  i := huft_build ( pword ( @l ), 288, 257, pushlist ( @cplens ), pushlist ( @cplext ), @tl, bl );
  IF i <> huft_complete THEN BEGIN
    inflate_fixed := i;
    exit
  END;
  FOR i := 0 TO 29 DO l [ i ] := 5;    {make an incomplete code set}
  bd := 5;
  i := huft_build ( pword ( @l ), 30, 0, pushlist ( @cpdist ), pushlist ( @cpdext ), @td, bd );
  IF i > huft_incomplete THEN BEGIN
    huft_free ( tl );
    inflate_fixed := unzip_ZipFileErr;
    exit
  END;
  inflate_fixed := inflate_codes ( tl, td, bl, bd );
  huft_free ( tl );
  huft_free ( td );
END;

{**************************** decompress dynamic block **************************}

FUNCTION inflate_dynamic : integer;
VAR i : integer;                      {temporary variables}
    j,
    l,                              {last length}
    m,                              {mask for bit length table}
    n : word;                         {number of lengths to get}
    tl,                             {literal/length code table}
    td : phuftlist;                   {distance code table}
    bl, bd : integer;                  {lookup bits for tl/bd}
    nb, nl, nd : word;                  {number of bit length/literal length/distance codes}
    ll : ARRAY [ 0..288 + 32 -1 ] of word;  {literal/length and distance code lengths}

BEGIN
  {read in table lengths}
  NEEDBITS ( 5 );
  nl := 257 + word ( b ) AND $1f;
  DUMPBITS ( 5 );
  NEEDBITS ( 5 );
  nd := 1 + word ( b ) AND $1f;
  DUMPBITS ( 5 );
  NEEDBITS ( 4 );
  nb := 4 + word ( b ) AND $f;
  DUMPBITS ( 4 );
  IF ( nl > 288 ) OR ( nd > 32 ) THEN BEGIN
    inflate_dynamic := 1;
    exit
  END;
  fillchar ( ll, sizeof ( ll ), #0 );

  {read in bit-length-code lengths}
  FOR j := 0 TO nb -1 DO BEGIN
    NEEDBITS ( 3 );
    ll [ border [ j ] ] := b AND 7;
    DUMPBITS ( 3 );
  END;
  FOR j := nb TO 18 DO ll [ border [ j ] ] := 0;

  {build decoding table for trees--single level, 7 bit lookup}
  bl := 7;
  i := huft_build ( pword ( @ll ), 19, 19, NIL, NIL, @tl, bl );
  IF i <> huft_complete THEN BEGIN
    IF i = huft_incomplete THEN huft_free ( tl ); {other errors: already freed}
    inflate_dynamic := unzip_ZipFileErr;
    exit
  END;

  {read in literal and distance code lengths}
  n := nl + nd;
  m := mask_bits [ bl ];
  i := 0; l := 0;
  WHILE word ( i ) < n DO BEGIN
    NEEDBITS ( bl );
    td := @tl^ [ b AND m ];
    j := phuft ( td ) ^.b;
    DUMPBITS ( j );
    j := phuft ( td ) ^.v_n;
    IF j < 16 THEN BEGIN            {length of code in bits (0..15)}
      l := j;                       {ave last length in l}
      ll [ i ] := l;
      inc ( i )
    END ELSE IF j = 16 THEN BEGIN   {repeat last length 3 to 6 times}
      NEEDBITS ( 2 );
      j := 3 + b AND 3;
      DUMPBITS ( 2 );
      IF i + j > n THEN BEGIN
        inflate_dynamic := 1;
        exit
      END;
      WHILE j > 0 DO BEGIN
        ll [ i ] := l;
        dec ( j );
        inc ( i );
      END;
    END ELSE IF j = 17 THEN BEGIN   {3 to 10 zero length codes}
      NEEDBITS ( 3 );
      j := 3 + b AND 7;
      DUMPBITS ( 3 );
      IF i + j > n THEN BEGIN
        inflate_dynamic := 1;
        exit
      END;
      WHILE j > 0 DO BEGIN
        ll [ i ] := 0;
        inc ( i );
        dec ( j );
      END;
      l := 0;
    END ELSE BEGIN                {j == 18: 11 to 138 zero length codes}
      NEEDBITS ( 7 );
      j := 11 + b AND $7f;
      DUMPBITS ( 7 );
      IF i + j > n THEN BEGIN
        inflate_dynamic := unzip_zipfileErr;
        exit
      END;
      WHILE j > 0 DO BEGIN
        ll [ i ] := 0;
        dec ( j );
        inc ( i );
      END;
      l := 0;
    END;
  END;
  huft_free ( tl );        {free decoding table for trees}

  {build the decoding tables for literal/length and distance codes}
  bl := lbits;
  i := huft_build ( pword ( @ll ), nl, 257, pushlist ( @cplens ), pushlist ( @cplext ), @tl, bl );
  IF i <> huft_complete THEN BEGIN
    IF i = huft_incomplete THEN huft_free ( tl );
    inflate_dynamic := unzip_ZipFileErr;
    exit
  END;
  bd := dbits;
  i := huft_build ( pword ( @ll [ nl ] ), nd, 0, pushlist ( @cpdist ), pushlist ( @cpdext ), @td, bd );
  IF i > huft_incomplete THEN BEGIN {pkzip bug workaround}
    IF i = huft_incomplete THEN huft_free ( td );
    huft_free ( tl );
    inflate_dynamic := unzip_ZipFileErr;
    exit
  END;
  {decompress until an end-of-block code}
  inflate_dynamic := inflate_codes ( tl, td, bl, bd );
  huft_free ( tl );
  huft_free ( td );
END;

{**************************** decompress a block ******************************}

FUNCTION inflate_block ( VAR e : integer ) : integer;
VAR t : word;           {block type}

BEGIN
  NEEDBITS ( 1 );
  e := b AND 1;
  DUMPBITS ( 1 );

  NEEDBITS ( 2 );
  t := b AND 3;
  DUMPBITS ( 2 );

  CASE t of
    2 : inflate_block := inflate_dynamic;
    0 : inflate_block := inflate_stored;
    1 : inflate_block := inflate_fixed;
  ELSE
    inflate_block := unzip_ZipFileErr;  {bad block type}
  END;
END;

{**************************** decompress an inflated entry **************************}

FUNCTION inflate : integer;
VAR e,                 {last block flag}
    r : integer;         {result code}

BEGIN
  inpos := 0;            {Input buffer position}
  readpos := -1;         {Nothing read}

  {initialize window, bit buffer}
  w := 0;
  k := 0;
  b := 0;

  {decompress until the last block}
  REPEAT
    r := inflate_block ( e );
    IF r <> 0 THEN BEGIN
      inflate := r;
      exit
    END;
  UNTIL e <> 0;
  {flush out slide}
  IF NOT flush ( w ) THEN inflate := unzip_WriteErr
  ELSE inflate := unzip_Ok;
END;
(***************************************************************************)
{.$I z_copyst.pas}  {Copy stored file}
{include for unzip.pas: Copy stored file}

{C code by info-zip group, translated to Pascal by Christian Ghisler}
{based on unz51g.zip}

{************************* copy stored file ************************************}
FUNCTION copystored : integer;
VAR readin : longint;
    outcnt : nword;
BEGIN
  WHILE ( reachedsize < compsize ) AND NOT totalabort DO BEGIN
    readin := compsize -reachedsize;
    IF readin > wsize THEN readin := wsize;
    {$I-}
    blockread ( infile, slide [ 0 ], readin, outcnt );  {Use slide as buffer}
    {$I+}
    IF ( outcnt <> readin ) OR ( ioresult <> 0 ) THEN BEGIN
      copystored := unzip_ReadErr;
      exit
    END;
    IF NOT flush ( outcnt ) THEN BEGIN  {Flushoutput takes care of CRC too}
      copystored := unzip_WriteErr;
      exit
    END;
    inc ( reachedsize, outcnt );
  END;
  IF NOT totalabort THEN
    copystored := unzip_Ok
  ELSE
    copystored := unzip_Userabort;
END;
(***************************************************************************)
{.$I z_explod.pas}  {Explode imploded file}
{include for unzip.pas: Explode imploded file}

{C code by info-zip group, translated to Pascal by Christian Ghisler}
{based on unz51g.zip}

{************************************* explode ********************************}

{*********************************** read in tree *****************************}
FUNCTION get_tree ( l : pword;n : word ) : integer;
VAR i, k, j, b : word;
    bytebuf : byte;

BEGIN
  READBYTE ( bytebuf );
  i := bytebuf;
  inc ( i );
  k := 0;
  REPEAT
    READBYTE ( bytebuf );
    j := bytebuf;
    b := ( j AND $F ) + 1;
    j := ( ( j AND $F0 ) SHR 4 ) + 1;
    IF ( k + j ) > n THEN BEGIN
      get_tree := 4;
      exit
    END;
    REPEAT
      l^ := b;
      inc ( ptrint ( l ), sizeof ( word ) );
      inc ( k );
      dec ( j );
    UNTIL j = 0;
    dec ( i );
  UNTIL i = 0;
  IF k <> n THEN get_tree := 4 ELSE get_tree := 0;
END;

{******************exploding, method: 8k slide, 3 trees ***********************}

FUNCTION explode_lit8 ( tb, tl, td : phuftlist;bb, bl, bd : integer ) : integer;
VAR s : longint;
    e : word;
    n, d : word;
    w : word;
    t : phuft;
    mb, ml, md : word;
    u : word;

BEGIN
  b := 0; k := 0; w := 0;
  u := 1;
  mb := mask_bits [ bb ];
  ml := mask_bits [ bl ];
  md := mask_bits [ bd ];
  s := uncompsize;
  WHILE ( s > 0 ) AND NOT ( totalabort OR zipeof ) DO BEGIN
    NEEDBITS ( 1 );
    IF ( b AND 1 ) <> 0 THEN BEGIN  {Litteral}
      DUMPBITS ( 1 );
      dec ( s );
      NEEDBITS ( bb );
      t := @tb^ [  ( NOT b ) AND mb ];
      e := t^.e;
      IF e > 16 THEN REPEAT
        IF e = 99 THEN BEGIN
          explode_lit8 := unzip_ZipFileErr;
          exit
        END;
        DUMPBITS ( t^.b );
        dec ( e, 16 );
        NEEDBITS ( e );
        t := @t^.v_t^ [  ( NOT b ) AND mask_bits [ e ] ];
        e := t^.e;
      UNTIL e <= 16;
      DUMPBITS ( t^.b );
      slide [ w ] := char ( t^.v_n );
      inc ( w );
      IF w = WSIZE THEN BEGIN
        IF NOT flush ( w ) THEN BEGIN
          explode_lit8 := unzip_WriteErr;
          exit
        END;
        w := 0; u := 0;
      END;
    END ELSE BEGIN
      DUMPBITS ( 1 );
      NEEDBITS ( 7 );
      d := b AND $7F;
      DUMPBITS ( 7 );
      NEEDBITS ( bd );
      t := @td^ [  ( NOT b ) AND md ];
      e := t^.e;
      IF e > 16 THEN REPEAT
        IF e = 99 THEN BEGIN
          explode_lit8 := unzip_ZipFileErr;
          exit
        END;
        DUMPBITS ( t^.b );
        dec ( e, 16 );
        NEEDBITS ( e );
        t := @t^.v_t^ [  ( NOT b ) AND mask_bits [ e ] ];
        e := t^.e;
      UNTIL e <= 16;
      DUMPBITS ( t^.b );

      d := w -d -t^.v_n;
      NEEDBITS ( bl );
      t := @tl^ [  ( NOT b ) AND ml ];
      e := t^.e;
      IF e > 16 THEN REPEAT
        IF e = 99 THEN BEGIN
          explode_lit8 := unzip_ZipFileErr;
          exit
        END;
        DUMPBITS ( t^.b );
        dec ( e, 16 );
        NEEDBITS ( e );
        t := @t^.v_t^ [  ( NOT b ) AND mask_bits [ e ] ];
        e := t^.e;
      UNTIL e <= 16;

      DUMPBITS ( t^.b );

      n := t^.v_n;
      IF e <> 0 THEN BEGIN
        NEEDBITS ( 8 );
        inc ( n, byte ( b ) AND $ff );
        DUMPBITS ( 8 );
      END;
      dec ( s, n );
      REPEAT
        d := d AND pred ( WSIZE );
        IF d > w THEN e := WSIZE -d ELSE e := WSIZE -w;
        IF e > n THEN e := n;
        dec ( n, e );
        IF ( u <> 0 ) AND ( w <= d ) THEN BEGIN
          fillchar ( slide [ w ], e, #0 );
          inc ( w, e );
          inc ( d, e );
        END ELSE IF ( w -d >= e ) THEN BEGIN
          move ( slide [ d ], slide [ w ], e );
          inc ( w, e );
          inc ( d, e );
        END ELSE REPEAT
          slide [ w ] := slide [ d ];
          inc ( w );
          inc ( d );
          dec ( e );
        UNTIL e = 0;
        IF w = WSIZE THEN BEGIN
          IF NOT flush ( w ) THEN BEGIN
            explode_lit8 := unzip_WriteErr;
            exit
          END;
          w := 0; u := 0;
        END;
      UNTIL n = 0;
    END;
  END;
  IF totalabort THEN explode_lit8 := unzip_userabort
  ELSE
    IF NOT flush ( w ) THEN explode_lit8 := unzip_WriteErr
  ELSE
    IF zipeof THEN explode_lit8 := unzip_readErr
  ELSE
    explode_lit8 := unzip_Ok;
END;

{******************exploding, method: 4k slide, 3 trees ***********************}

FUNCTION explode_lit4 ( tb, tl, td : phuftlist;bb, bl, bd : integer ) : integer;
VAR s : longint;
    e : word;
    n, d : word;
    w : word;
    t : phuft;
    mb, ml, md : word;
    u : word;

BEGIN
  b := 0; k := 0; w := 0;
  u := 1;
  mb := mask_bits [ bb ];
  ml := mask_bits [ bl ];
  md := mask_bits [ bd ];
  s := uncompsize;
  WHILE ( s > 0 ) AND NOT ( totalabort OR zipeof ) DO BEGIN
    NEEDBITS ( 1 );
    IF ( b AND 1 ) <> 0 THEN BEGIN  {Litteral}
      DUMPBITS ( 1 );
      dec ( s );
      NEEDBITS ( bb );
      t := @tb^ [  ( NOT b ) AND mb ];
      e := t^.e;
      IF e > 16 THEN REPEAT
        IF e = 99 THEN BEGIN
          explode_lit4 := unzip_ZipFileErr;
          exit
        END;
        DUMPBITS ( t^.b );
        dec ( e, 16 );
        NEEDBITS ( e );
        t := @t^.v_t^ [  ( NOT b ) AND mask_bits [ e ] ];
        e := t^.e;
      UNTIL e <= 16;
      DUMPBITS ( t^.b );
      slide [ w ] := char ( t^.v_n );
      inc ( w );
      IF w = WSIZE THEN BEGIN
        IF NOT flush ( w ) THEN BEGIN
          explode_lit4 := unzip_WriteErr;
          exit
        END;
        w := 0; u := 0;
      END;
    END ELSE BEGIN
      DUMPBITS ( 1 );
      NEEDBITS ( 6 );
      d := b AND $3F;
      DUMPBITS ( 6 );
      NEEDBITS ( bd );
      t := @td^ [  ( NOT b ) AND md ];
      e := t^.e;
      IF e > 16 THEN REPEAT
        IF e = 99 THEN BEGIN
          explode_lit4 := unzip_ZipFileErr;
          exit
        END;
        DUMPBITS ( t^.b );
        dec ( e, 16 );
        NEEDBITS ( e );
        t := @t^.v_t^ [  ( NOT b ) AND mask_bits [ e ] ];
        e := t^.e;
      UNTIL e <= 16;
      DUMPBITS ( t^.b );
      d := w -d -t^.v_n;
      NEEDBITS ( bl );
      t := @tl^ [  ( NOT b ) AND ml ];
      e := t^.e;
      IF e > 16 THEN REPEAT
        IF e = 99 THEN BEGIN
          explode_lit4 := unzip_ZipFileErr;
          exit
        END;
        DUMPBITS ( t^.b );
        dec ( e, 16 );
        NEEDBITS ( e );
        t := @t^.v_t^ [  ( NOT b ) AND mask_bits [ e ] ];
        e := t^.e;
      UNTIL e <= 16;

      DUMPBITS ( t^.b );
      n := t^.v_n;
      IF e <> 0 THEN BEGIN
        NEEDBITS ( 8 );
        inc ( n, b AND $ff );
        DUMPBITS ( 8 );
      END;
      dec ( s, n );
      REPEAT
        d := d AND pred ( WSIZE );
        IF d > w THEN e := WSIZE -d ELSE e := WSIZE -w;
        IF e > n THEN e := n;
        dec ( n, e );
        IF ( u <> 0 ) AND ( w <= d ) THEN BEGIN
          fillchar ( slide [ w ], e, #0 );
          inc ( w, e );
          inc ( d, e );
        END ELSE IF ( w -d >= e ) THEN BEGIN
          move ( slide [ d ], slide [ w ], e );
          inc ( w, e );
          inc ( d, e );
        END ELSE REPEAT
          slide [ w ] := slide [ d ];
          inc ( w );
          inc ( d );
          dec ( e );
        UNTIL e = 0;
        IF w = WSIZE THEN BEGIN
          IF NOT flush ( w ) THEN BEGIN
            explode_lit4 := unzip_WriteErr;
            exit
          END;
          w := 0; u := 0;
        END;
      UNTIL n = 0;
    END;
  END;
  IF totalabort THEN explode_lit4 := unzip_userabort
  ELSE
  IF NOT flush ( w ) THEN explode_lit4 := unzip_WriteErr
  ELSE
    IF zipeof THEN explode_lit4 := unzip_readErr
  ELSE explode_lit4 := unzip_Ok;
END;

{******************exploding, method: 8k slide, 2 trees ***********************}

FUNCTION explode_nolit8 ( tl, td : phuftlist;bl, bd : integer ) : integer;
VAR s : longint;
    e : word;
    n, d : word;
    w : word;
    t : phuft;
    ml, md : word;
    u : word;

BEGIN
  b := 0; k := 0; w := 0;
  u := 1;
  ml := mask_bits [ bl ];
  md := mask_bits [ bd ];
  s := uncompsize;
  WHILE ( s > 0 ) AND NOT ( totalabort OR zipeof ) DO BEGIN
    NEEDBITS ( 1 );
    IF ( b AND 1 ) <> 0 THEN BEGIN  {Litteral}
      DUMPBITS ( 1 );
      dec ( s );
      NEEDBITS ( 8 );
      slide [ w ] := char ( b );
      inc ( w );
      IF w = WSIZE THEN BEGIN
        IF NOT flush ( w ) THEN BEGIN
          explode_nolit8 := unzip_WriteErr;
          exit
        END;
        w := 0; u := 0;
      END;
      DUMPBITS ( 8 );
    END ELSE BEGIN
      DUMPBITS ( 1 );
      NEEDBITS ( 7 );
      d := b AND $7F;
      DUMPBITS ( 7 );
      NEEDBITS ( bd );
      t := @td^ [  ( NOT b ) AND md ];
      e := t^.e;
      IF e > 16 THEN REPEAT
        IF e = 99 THEN BEGIN
          explode_nolit8 := unzip_ZipFileErr;
          exit
        END;
        DUMPBITS ( t^.b );
        dec ( e, 16 );
        NEEDBITS ( e );
        t := @t^.v_t^ [  ( NOT b ) AND mask_bits [ e ] ];
        e := t^.e;
      UNTIL e <= 16;
      DUMPBITS ( t^.b );

      d := w -d -t^.v_n;
      NEEDBITS ( bl );
      t := @tl^ [  ( NOT b ) AND ml ];
      e := t^.e;
      IF e > 16 THEN REPEAT
        IF e = 99 THEN BEGIN
          explode_nolit8 := unzip_ZipFileErr;
          exit
        END;
        DUMPBITS ( t^.b );
        dec ( e, 16 );
        NEEDBITS ( e );
        t := @t^.v_t^ [  ( NOT b ) AND mask_bits [ e ] ];
        e := t^.e;
      UNTIL e <= 16;

      DUMPBITS ( t^.b );

      n := t^.v_n;
      IF e <> 0 THEN BEGIN
        NEEDBITS ( 8 );
        inc ( n, b AND $ff );
        DUMPBITS ( 8 );
      END;
      dec ( s, n );
      REPEAT
        d := d AND pred ( WSIZE );
        IF d > w THEN e := WSIZE -d ELSE e := WSIZE -w;
        IF e > n THEN e := n;
        dec ( n, e );
        IF ( u <> 0 ) AND ( w <= d ) THEN BEGIN
          fillchar ( slide [ w ], e, #0 );
          inc ( w, e );
          inc ( d, e );
        END ELSE IF ( w -d >= e ) THEN BEGIN
          move ( slide [ d ], slide [ w ], e );
          inc ( w, e );
          inc ( d, e );
        END ELSE REPEAT
          slide [ w ] := slide [ d ];
          inc ( w );
          inc ( d );
          dec ( e );
        UNTIL e = 0;
        IF w = WSIZE THEN BEGIN
          IF NOT flush ( w ) THEN BEGIN
            explode_nolit8 := unzip_WriteErr;
            exit
          END;
          w := 0; u := 0;
        END;
      UNTIL n = 0;
    END;
  END;
  IF totalabort THEN explode_nolit8 := unzip_userabort
  ELSE
  IF NOT flush ( w ) THEN explode_nolit8 := unzip_WriteErr
  ELSE
    IF zipeof THEN explode_nolit8 := unzip_readErr
  ELSE explode_nolit8 := unzip_Ok;
END;

{******************exploding, method: 4k slide, 2 trees ***********************}

FUNCTION explode_nolit4 ( tl, td : phuftlist;bl, bd : integer ) : integer;
VAR s : longint;
    e : word;
    n, d : word;
    w : word;
    t : phuft;
    ml, md : word;
    u : word;

BEGIN
  b := 0; k := 0; w := 0;
  u := 1;
  ml := mask_bits [ bl ];
  md := mask_bits [ bd ];
  s := uncompsize;
  WHILE ( s > 0 ) AND NOT ( totalabort OR zipeof ) DO BEGIN
    NEEDBITS ( 1 );
    IF ( b AND 1 ) <> 0 THEN BEGIN  {Litteral}
      DUMPBITS ( 1 );
      dec ( s );
      NEEDBITS ( 8 );
      slide [ w ] := char ( b );
      inc ( w );
      IF w = WSIZE THEN BEGIN
        IF NOT flush ( w ) THEN BEGIN
          explode_nolit4 := unzip_WriteErr;
          exit
        END;
        w := 0; u := 0;
      END;
      DUMPBITS ( 8 );
    END ELSE BEGIN
      DUMPBITS ( 1 );
      NEEDBITS ( 6 );
      d := b AND $3F;
      DUMPBITS ( 6 );
      NEEDBITS ( bd );
      t := @td^ [  ( NOT b ) AND md ];
      e := t^.e;
      IF e > 16 THEN REPEAT
        IF e = 99 THEN BEGIN
          explode_nolit4 := unzip_ZipFileErr;
          exit
        END;
        DUMPBITS ( t^.b );
        dec ( e, 16 );
        NEEDBITS ( e );
        t := @t^.v_t^ [  ( NOT b ) AND mask_bits [ e ] ];
        e := t^.e;
      UNTIL e <= 16;
      DUMPBITS ( t^.b );
      d := w -d -t^.v_n;
      NEEDBITS ( bl );
      t := @tl^ [  ( NOT b ) AND ml ];
      e := t^.e;
      IF e > 16 THEN REPEAT
        IF e = 99 THEN BEGIN
          explode_nolit4 := unzip_ZipFileErr;
          exit
        END;
        DUMPBITS ( t^.b );
        dec ( e, 16 );
        NEEDBITS ( e );
        t := @t^.v_t^ [  ( NOT b ) AND mask_bits [ e ] ];
        e := t^.e;
      UNTIL e <= 16;

      DUMPBITS ( t^.b );
      n := t^.v_n;
      IF e <> 0 THEN BEGIN
        NEEDBITS ( 8 );
        inc ( n, b AND $ff );
        DUMPBITS ( 8 );
      END;
      dec ( s, n );
      REPEAT
        d := d AND pred ( WSIZE );
        IF d > w THEN e := WSIZE -d ELSE e := WSIZE -w;
        IF e > n THEN e := n;
        dec ( n, e );
        IF ( u <> 0 ) AND ( w <= d ) THEN BEGIN
          fillchar ( slide [ w ], e, #0 );
          inc ( w, e );
          inc ( d, e );
        END ELSE IF ( w -d >= e ) THEN BEGIN
          move ( slide [ d ], slide [ w ], e );
          inc ( w, e );
          inc ( d, e );
        END ELSE REPEAT
          slide [ w ] := slide [ d ];
          inc ( w );
          inc ( d );
          dec ( e );
        UNTIL e = 0;
        IF w = WSIZE THEN BEGIN
          IF NOT flush ( w ) THEN BEGIN
            explode_nolit4 := unzip_WriteErr;
            exit
          END;
          w := 0; u := 0;
        END;
      UNTIL n = 0;
    END;
  END;
  IF totalabort THEN explode_nolit4 := unzip_userabort
  ELSE
  IF NOT flush ( w ) THEN explode_nolit4 := unzip_WriteErr
  ELSE
    IF zipeof THEN explode_nolit4 := unzip_readErr
  ELSE explode_nolit4 := unzip_Ok;
END;

{****************************** explode *********************************}

FUNCTION explode : integer;
VAR r : integer;
    tb, tl, td : phuftlist;
    bb, bl, bd : integer;
    l : ARRAY [ 0..255 ] of word;

BEGIN
  inpos := 0;
  readpos := -1;  {Nothing read in}
  bl := 7;
  IF compsize > 200000 THEN bd := 8 ELSE bd := 7;
  IF hufttype AND 4 <> 0 THEN BEGIN
    bb := 9;
    r := get_tree ( @l [ 0 ], 256 );
    IF r <> 0 THEN BEGIN
      explode := unzip_ZipFileErr;
      exit
    END;
    r := huft_build ( @l, 256, 256, NIL, NIL, @tb, bb );
    IF r <> 0 THEN BEGIN
      IF r = huft_incomplete THEN huft_free ( tb );
      explode := unzip_ZipFileErr;
      exit
    END;
    r := get_tree ( @l [ 0 ], 64 );
    IF r <> 0 THEN BEGIN
      huft_free ( tb );
      explode := unzip_ZipFileErr;
      exit
    END;
    r := huft_build ( @l, 64, 0, pushlist ( @cplen3 ), pushlist ( @extra ), @tl, bl );
    IF r <> 0 THEN BEGIN
      IF r = huft_incomplete THEN huft_free ( tl );
      huft_free ( tb );
      explode := unzip_ZipFileErr;
      exit
    END;
    r := get_tree ( @l [ 0 ], 64 );
    IF r <> 0 THEN BEGIN
      huft_free ( tb );
      huft_free ( tl );
      explode := unzip_ZipFileErr;
      exit
    END;
    IF hufttype AND 2 <> 0 THEN BEGIN {8k}
      r := huft_build ( @l, 64, 0, pushlist ( @cpdist8 ), pushlist ( @extra ), @td, bd );
      IF r <> 0 THEN BEGIN
        IF r = huft_incomplete THEN huft_free ( td );
        huft_free ( tb );
        huft_free ( tl );
        explode := unzip_ZipFileErr;
        exit
      END;
      r := explode_lit8 ( tb, tl, td, bb, bl, bd );
    END ELSE BEGIN
      r := huft_build ( @l, 64, 0, pushlist ( @cpdist4 ), pushlist ( @extra ), @td, bd );
      IF r <> 0 THEN BEGIN
        IF r = huft_incomplete THEN huft_free ( td );
        huft_free ( tb );
        huft_free ( tl );
        explode := unzip_ZipFileErr;
        exit
      END;
      r := explode_lit4 ( tb, tl, td, bb, bl, bd );
    END;
    huft_free ( td );
    huft_free ( tl );
    huft_free ( tb );
  END ELSE BEGIN       {No literal tree}
    r := get_tree ( @l [ 0 ], 64 );
    IF r <> 0 THEN BEGIN
      explode := unzip_ZipFileErr;
      exit
    END;
    r := huft_build ( @l, 64, 0, pushlist ( @cplen2 ), pushlist ( @extra ), @tl, bl );
    IF r <> 0 THEN BEGIN
      IF r = huft_incomplete THEN huft_free ( tl );
      explode := unzip_ZipFileErr;
      exit
    END;

    r := get_tree ( @l [ 0 ], 64 );
    IF r <> 0 THEN BEGIN
      huft_free ( tl );
      explode := unzip_ZipFileErr;
      exit
    END;
    IF hufttype AND 2 <> 0 THEN BEGIN {8k}
      r := huft_build ( @l, 64, 0, pushlist ( @cpdist8 ), pushlist ( @extra ), @td, bd );
      IF r <> 0 THEN BEGIN
        IF r = huft_incomplete THEN huft_free ( td );
        huft_free ( tl );
        explode := unzip_ZipFileErr;
        exit
      END;
      r := explode_nolit8 ( tl, td, bl, bd );
    END ELSE BEGIN
      r := huft_build ( @l, 64, 0, pushlist ( @cpdist4 ), pushlist ( @extra ), @td, bd );
      IF r <> 0 THEN BEGIN
        IF r = huft_incomplete THEN huft_free ( td );
        huft_free ( tl );
        explode := unzip_ZipFileErr;
        exit
      END;
      r := explode_nolit4 ( tl, td, bl, bd );
    END;
    huft_free ( td );
    huft_free ( tl );
  END;
  explode := r;
END;
(***************************************************************************)
{.$I z_shrunk.pas}  {Unshrink function}
{*************************** unshrink **********************************}
{Written and NOT copyrighted by Christian Ghisler.
 I have rewritten unshrink because the original
 function was copyrighted by Mr. Smith of Info-zip
 This funtion here is now completely FREE!!!!
 The only right I claim on this code is that
 noone else claims a copyright on it!}


CONST max_code = 8192;
      max_stack = 8192;
      initial_code_size = 9;
      final_code_size = 13;
      write_max = wsize -3 * ( max_code -256 ) -max_stack -2;  {Rest of slide=write buffer}
                                                     {=766 bytes}

TYPE prev = ARRAY [ 257..max_code ] of integer;
     pprev = ^prev;
     cds = ARRAY [ 257..max_code ] of char;
     pcds = ^cds;
     stacktype = ARRAY [ 0..max_stack ] of char;
     pstacktype = ^stacktype;
     writebuftype = ARRAY [ 0..write_max ] of char;   {write buffer}
     pwritebuftype = ^writebuftype;

VAR previous_code : pprev;       {previous code trie}
    actual_code : pcds;          {actual code trie}
    stack : pstacktype;          {Stack for output}
    writebuf : pwritebuftype;    {Write buffer}
    next_free,                 {Next free code in trie}
    write_ptr : integer;         {Pointer to output buffer}

FUNCTION unshrink_flush : boolean;
VAR
n : nword;
b : boolean;
BEGIN
  {$I-}
  blockwrite ( outfile, writebuf^ [ 0 ], write_ptr, n );
  {$I+}
  b := ( n = write_ptr ) AND ( ioresult = 0 );  {True-> alles ok}
  UpdateCRC ( iobuf ( pointer ( @writebuf^ [ 0 ] ) ^ ), write_ptr );
  {--}
{$IFDEF FPC}
  IF ( b = TRUE ) AND Assigned(ZipReport)  {callback report for high level functions}
{$ELSE}
  IF ( b = TRUE ) AND ( @ZipReport <> NIL )  {callback report for high level functions}
{$ENDIF}
  THEN BEGIN
      WITH ZipRec DO BEGIN
           Status := file_unzipping;
           ZipReport ( n, @ZipRec );    {report the actual bytes written}
      END;
  END; {report}
  unshrink_flush := b;
END;

FUNCTION write_char ( c : char ) : boolean;
BEGIN
  writebuf^ [ write_ptr ] := c;
  inc ( write_ptr );
  IF write_ptr > write_max THEN BEGIN
    write_char := unshrink_flush;
    write_ptr := 0;
  END ELSE write_char := TRUE;
END;

PROCEDURE ClearLeafNodes;
VAR pc,                    {previous code}
    i,                     {index}
    act_max_code : integer;  {max code to be searched for leaf nodes}
    previous : pprev;   {previous code trie}

BEGIN
  previous := previous_code;
  act_max_code := next_free -1;
  FOR i := 257 TO act_max_code DO
    previous^ [ i ] := previous^ [ i ] OR $8000;
  FOR i := 257 TO act_max_code DO BEGIN
    pc := previous^ [ i ] AND NOT $8000;
    IF pc > 256 THEN
      previous^ [ pc ] := previous^ [ pc ] AND ( NOT $8000 );
  END;
  {Build new free list}
  pc := -1;
  next_free := -1;
  FOR i := 257 TO act_max_code DO
    IF previous^ [ i ] AND $C000 <> 0 THEN BEGIN {Either free before or marked now}
      IF pc <> -1 THEN previous^ [ pc ] := -i     {Link last item to this item}
                ELSE next_free := i;
      pc := i;
    END;
  IF pc <> -1 THEN
    previous^ [ pc ] := -act_max_code -1;
END;


FUNCTION unshrink : integer;

VAR incode : integer;            {code read in}
    lastincode : integer;        {last code read in}
    lastoutcode : char;          {last code emitted}
    code_size : byte;            {Actual code size}
    stack_ptr,                 {Stackpointer}
    new_code,                  {Save new code read}
    code_mask,                 {mask for coding}
    i : integer;                 {Index}
    bits_to_read : longint;

BEGIN
  IF compsize = maxlongint THEN BEGIN   {Compressed Size was not in header!}
    unshrink := unzip_NotSupported;
    exit
  END;
  inpos := 0;            {Input buffer position}
  readpos := -1;         {Nothing read}

  {initialize window, bit buffer}
  w := 0;
  k := 0;
  b := 0;

  {Initialize pointers for various buffers}
  previous_code := @slide [ 0 ];
  actual_code := @slide [ sizeof ( prev ) ];
  stack := @slide [ sizeof ( prev ) + sizeof ( cds ) ];
  writebuf := @slide [ sizeof ( prev ) + sizeof ( cds ) + sizeof ( stacktype ) ];
  fillchar ( slide^, wsize, #0 );

  {initialize free codes list}
  FOR i := 257 TO max_code DO
    previous_code^ [ i ] := - ( i + 1 );
  next_free := 257;
  stack_ptr := max_stack;
  write_ptr := 0;
  code_size := initial_code_size;
  code_mask := mask_bits [ code_size ];

  NEEDBITS ( code_size );
  incode := b AND code_mask;
  DUMPBITS ( code_size );

  lastincode := incode;
  lastoutcode := char ( incode );
  IF NOT write_char ( lastoutcode ) THEN BEGIN
    unshrink := unzip_writeErr;
    exit
  END;

  bits_to_read := 8 * compsize -code_size;   {Bits to be read}

  WHILE NOT totalabort AND ( bits_to_read >= code_size ) DO BEGIN
    NEEDBITS ( code_size );
    incode := b AND code_mask;
    DUMPBITS ( code_size );
    dec ( bits_to_read, code_size );
    IF incode = 256 THEN BEGIN            {Special code}
      NEEDBITS ( code_size );
      incode := b AND code_mask;
      DUMPBITS ( code_size );
      dec ( bits_to_read, code_size );
      CASE incode of
        1 : BEGIN
          inc ( code_size );
          IF code_size > final_code_size THEN BEGIN
            unshrink := unzip_ZipFileErr;
            exit
          END;
          code_mask := mask_bits [ code_size ];
        END;
        2 : BEGIN
          ClearLeafNodes;
        END;
      ELSE
        unshrink := unzip_ZipFileErr;
        exit
      END;
    END ELSE BEGIN
      new_code := incode;
      IF incode < 256 THEN BEGIN          {Simple char}
        lastoutcode := char ( incode );
        IF NOT write_char ( lastoutcode ) THEN BEGIN
          unshrink := unzip_writeErr;
          exit
        END;
      END ELSE BEGIN
        IF previous_code^ [ incode ] < 0 THEN BEGIN
          stack^ [ stack_ptr ] := lastoutcode;
          dec ( stack_ptr );
          incode := lastincode;
        END;
        WHILE incode > 256 DO BEGIN
          stack^ [ stack_ptr ] := actual_code^ [ incode ];
          dec ( stack_ptr );
          incode := previous_code^ [ incode ];
        END;
        lastoutcode := char ( incode );
        IF NOT write_char ( lastoutcode ) THEN BEGIN
          unshrink := unzip_writeErr;
          exit
        END;
        FOR i := stack_ptr + 1 TO max_stack DO
          IF NOT write_char ( stack^ [ i ] ) THEN BEGIN
            unshrink := unzip_writeErr;
            exit
          END;
        stack_ptr := max_stack;
      END;
      incode := next_free;
      IF incode <= max_code THEN BEGIN
        next_free := -previous_code^ [ incode ];   {Next node in free list}
        previous_code^ [ incode ] := lastincode;
        actual_code^ [ incode ] := lastoutcode;
      END;
      lastincode := new_code;
    END;
  END;
  IF totalabort THEN
    unshrink := unzip_UserAbort
  ELSE IF unshrink_flush THEN
    unshrink := unzip_ok
  ELSE
    unshrink := unzip_WriteErr;
END;
(***************************************************************************)
{***************************************************************************}
FUNCTION GetSupportedMethods : longint;
BEGIN
  GetSupportedMethods := 1 + ( 1 SHL 1 ) + ( 1 SHL 6 ) + ( 1 SHL 8 );
  {stored, shrunk, imploded and deflated}
END;

{******************** main low level function: unzipfile ********************}
{written and not copyrighted by Christian Ghisler}
FUNCTION unzipfile ( in_name : pchar;out_name : pchar;offset : longint;
  hFileAction : word;cm_index : integer ) : integer;
VAR err : integer;
    header : plocalheader;
    buf : ARRAY [ 0..tfSize+1 ] of char;
{$ifndef unix}
    buf0 : ARRAY [ 0..3 ] of char;
{$endif}
    storefilemode,
    timedate : longint;
    originalcrc : cardinal;    {crc from zip-header}
    ziptype, aResult : integer;
    p, p1 : pchar;
    isadir : boolean;
    oldcurdir : string [ 80 ];

BEGIN
  getmem ( slide, wsize );
  fillchar ( slide [ 0 ], wsize, #0 );
  assign ( infile, in_name );
  storefilemode := filemode;
  filemode := 0;
  {$I-}
  reset ( infile, 1 );
  {$I+}
  filemode := storefilemode;
  IF ioresult <> 0 THEN BEGIN
    freemem ( slide, wsize );
    unzipfile := unzip_ReadErr;
    inuse := FALSE;
    exit
  END;
  {$I-}
  seek ( infile, offset );       {seek to header position}
  {$I+}
  IF ioresult <> 0 THEN BEGIN
    freemem ( slide, wsize );
    close ( infile );
    unzipfile := unzip_ZipFileErr;
    inuse := FALSE;
    exit
  END;
  header := @inbuf;
  {$I-}
  blockread ( infile, header^, sizeof ( header^ ) );  {read in local header}
  {$I+}
  IF ioresult <> 0 THEN BEGIN
    freemem ( slide, wsize );
    close ( infile );
    unzipfile := unzip_ZipFileErr;
    inuse := FALSE;
    exit
  END;

  IF strlcomp ( header^.signature, 'PK'#3#4, 4 ) <> 0 THEN BEGIN
    freemem ( slide, wsize );
    close ( infile );
    unzipfile := unzip_ZipFileErr;
    inuse := FALSE;
    exit
  END;

  {calculate offset of data}
  offset := offset + header^.filename_len + header^.extra_field_len + sizeof ( tlocalheader );
  timedate := header^.file_timedate;
  IF ( hufttype AND 8 ) = 0 THEN BEGIN  {Size and crc at the beginning}
    compsize := header^.compress_size;
    uncompsize := header^.uncompress_size;
    originalcrc := header^.crc_32;
  END ELSE BEGIN
    compsize := maxlongint;           {Don't get a sudden zipeof!}
    uncompsize := maxlongint;
    originalcrc := 0
  END;
  ziptype := header^.zip_type;     {0=stored, 6=imploded, 8=deflated}
  IF ( 1 SHL ziptype ) AND GetSupportedMethods = 0 THEN BEGIN  {Not Supported!!!}
    freemem ( slide, wsize );
    close ( infile );
    unzipfile := unzip_NotSupported;
    inuse := FALSE;
    exit;
  END;
  hufttype := header^.bit_flag;
  IF ( hufttype AND 1 ) <> 0 THEN BEGIN {encrypted}
    freemem ( slide, wsize );
    close ( infile );
    unzipfile := unzip_Encrypted;
    inuse := FALSE;
    exit;
  END;

  reachedsize := 0;
  seek ( infile, offset );

  assign ( outfile, out_name );
  {$I-}
  rewrite ( outfile, 1 );
  {$I+}
  err := ioresult;
  {create directories not yet in path}
  isadir := ( out_name [ strlen ( out_name ) -1 ] in ['/','\'] );
  IF ( err = 3 ) OR isadir THEN BEGIN  {path not found}
    {$I-}
    getdir ( 0, oldcurdir );
    {$I+}
    err := ioresult;
    strcopy ( buf, out_name );
    p1 := strrscan ( buf, DirSep );
    IF p1 <> NIL THEN inc ( p1 );  {pointer to filename}
    p := strtok ( buf, DirSep );
{$ifndef unix}
    IF ( p <> NIL ) AND ( p [ 1 ] = ':' ) THEN BEGIN
      strcopy ( buf0, 'c:\' );    {set drive}
      buf0 [ 0 ] := p [ 0 ];
      {$I-}
      chdir ( buf0 );
      {$I+}
      err := ioresult;
      p := strtok ( NIL, '\' );
    END;
{$endif}
    WHILE ( p <> NIL ) AND ( p <> p1 ) DO BEGIN
      {$I-}
      chdir ( strpas ( p ) );
      {$I+}
      err := ioresult;
      IF err <> 0 THEN BEGIN
        {$I-}
        mkdir ( strpas ( p ) );
        {$I+}
        err := ioresult;
        IF err = 0 THEN
          {$I-}
          chdir ( strpas ( p ) );
          {$I+}
          err := ioresult;
      END;
      IF err = 0 THEN
        p := strtok ( NIL, DirSep )
      ELSE
        p := NIL;
    END;
    {$I-}
    chdir ( oldcurdir );
    {$I+}
    err := ioresult;
    IF isadir THEN BEGIN
      freemem ( slide, wsize );
      unzipfile := unzip_Ok;    {A directory -> ok}
      close ( infile );
      inuse := FALSE;
      exit;
    END;
    {$I-}
    rewrite ( outfile, 1 );
    {$I+}
    err := ioresult;
  END;

  IF err <> 0 THEN BEGIN
    freemem ( slide, wsize );
    unzipfile := unzip_WriteErr;
    close ( infile );
    inuse := FALSE;
    exit
  END;

  totalabort := FALSE;
  zipeof := FALSE;

  crc32val := $FFFFFFFF;

  {Unzip correct type}
  CASE ziptype of
    0 : aResult := copystored;
    1 : aResult := unshrink;
    6 : aResult := explode;
    8 : aResult := inflate;
  ELSE
    aResult := unzip_NotSupported;
  END;
  unzipfile := aResult;

  IF ( aResult = unzip_ok ) AND ( ( hufttype AND 8 ) <> 0 ) THEN BEGIN {CRC at the end}
    dumpbits ( k AND 7 );
    needbits ( 16 );
    originalcrc := b AND $FFFF;
    dumpbits ( 16 );
    needbits ( 16 );
    originalcrc := originalcrc OR LongWord(( b AND $FFFF ) SHL 16);
    dumpbits ( 16 );

    IF originalcrc = $08074b50 THEN BEGIN
      { skiping possible $08074b50 data descriptor signature. see PKWARE APPNOTE.txt }
      needbits ( 16 );
      originalcrc := b AND $FFFF;
      dumpbits ( 16 );
      needbits ( 16 );
      originalcrc := originalcrc OR LongWord(( b AND $FFFF ) SHL 16);
      dumpbits ( 16 );
    END;
  END;

  close ( infile );
  close ( outfile );
  crc32val := NOT ( crc32val );  {one's complement}
  IF aResult <> 0 THEN BEGIN
    erase ( outfile );
  END ELSE IF ( originalcrc <> crc32val ) THEN BEGIN
    unzipfile := unzip_CRCErr;
    erase ( outfile );
  END ELSE BEGIN
    filemode := 2;
    reset ( outfile );
    filemode := storefilemode;
    setftime ( outfile, timedate ); {set zipped time and date of oufile}
    close ( outfile );
  END;
  freemem ( slide, wsize );
  inuse := FALSE;
END;
{***************************************************************************}
{***************************************************************************}
{***************************************************************************}
{ other functions; zipread.pas }
CONST mainheader : pchar = 'PK'#5#6;
      maxbufsize = 64000;  {Can be as low as 500 Bytes; however, }
                         {this would lead to extensive disk reading!}
                         {If one entry (including Extra field) is bigger}
                         {than maxbufsize, you cannot read it :-( }

TYPE
  pheader = ^theader;
  pmainheader = ^tmainheader;
  tmainheader = PACKED RECORD
    signature : ARRAY [ 0..3 ] of char;  {'PK'#5#6}
    thisdisk,
    centralstartdisk,
    entries_this_disk,
    entries_central_dir : word;
    headsize,
    headstart : longint;
    comment_len : longint;
    unknown : word;
  END;
  theader = PACKED RECORD
    signature : ARRAY [ 0..3 ] of char;  {'PK'#1#2}
    OSversion,      {Operating system version}
    OSmadeby : byte;  {MSDOS (FAT): 0}
    extract_ver,
    bit_flag,
    zip_type : word;
    file_timedate : longint;
    crc_32,
    compress_size,
    uncompress_size : longint;
    filename_len,
    extra_field_len,
    file_comment_len,
    disk_number_start,
    internal_attr : word;
    external_attr : ARRAY [ 0..3 ] of byte;
    offset_local_header : longint;
  END;

{*********** Fill out tZipRec structure with next entry *************}

FUNCTION filloutRec ( VAR zprec : tZipRec ) : integer;
VAR p : pchar;
    incr : longint;
    header : pheader;
    offs : word;
    old : char;
    f : file;
    extra, err : nword;

BEGIN
 WITH zprec DO BEGIN
  header := pheader ( @buf^ [ localstart ] );
  IF ( bufsize = maxbufsize ) THEN BEGIN       {Caution: header bigger than 64k!}
    extra := sizeof ( file );
    IF ( ( localstart + sizeof ( theader ) ) > bufsize ) OR
      ( localstart + header^.filename_len + header^.extra_field_len +
      header^.file_comment_len + sizeof ( theader ) > bufsize )
      THEN BEGIN     {Read over end of header}
        move ( buf^ [ bufsize + 1 ], f, extra );   {Restore file}
        move ( buf^ [ localstart ], buf^ [ 0 ], bufsize -localstart );  {Move end to beginning in buffer}
        {$I-}
        blockread ( f, buf^ [ bufsize -localstart ], localstart, err );  {Read in full central dir, up to maxbufsize Bytes}
        {$I+}
        IF ( ioresult <> 0 ) OR ( err + localstart < sizeof ( theader ) ) THEN BEGIN
          filloutrec := unzip_nomoreitems;
          exit
        END;
        move ( f, buf^ [ bufsize + 1 ], extra );  {Save changed file info!}
        localstart := 0;
        header := pheader ( @buf^ [ localstart ] );
      END;
  END;
  IF ( localstart + 4 <= bufsize ) AND   {Here is the ONLY correct finish!}
    ( strlcomp ( header^.signature, mainheader, 4 ) = 0 ) THEN BEGIN  {Main header}
    filloutrec := unzip_nomoreitems;
    exit
  END;
  IF ( localstart + sizeof ( header ) > bufsize ) OR
    ( localstart + header^.filename_len + header^.extra_field_len +
    header^.file_comment_len + sizeof ( theader ) > bufsize ) OR
    ( strlcomp ( header^.signature, 'PK'#1#2, 4 ) <> 0 ) THEN BEGIN
    filloutrec := unzip_nomoreitems;
    exit
  END;
  size := header^.uncompress_size;
  compressSize := header^.compress_size;
  IF header^.osmadeby = 0 THEN
    attr := header^.external_attr [ 0 ]
  ELSE
    attr := 0;
  time := header^.file_timedate;
  headeroffset := header^.offset_local_header; {Other header size}
  Packmethod := header^.zip_type;
  offs := localstart + header^.filename_len + sizeof ( header^ );
  old := buf^ [ offs ];
  buf^ [ offs ] := #0;  {Repair signature of next block!}
  strlcopy ( filename, pchar ( @buf^ [ localstart + sizeof ( header^ ) ] ), sizeof ( filename ) -1 );
  buf^ [ offs ] := old;
{$ifndef unix}
  REPEAT           {Convert slash to backslash!}
    p := strscan ( filename, '/' );
    IF p <> NIL THEN p [ 0 ] := '\';
  UNTIL p = NIL;
{$else}
  REPEAT           {Convert backslash to slash!}
    p := strscan ( filename, '\' );
    IF p <> NIL THEN p [ 0 ] := '/';
  UNTIL p = NIL;
{$endif}
  incr := header^.filename_len + header^.extra_field_len +
        header^.file_comment_len + sizeof ( header^ );
  IF incr <= 0 THEN BEGIN
    filloutrec := unzip_InternalError;
    exit
  END;
  localstart := localstart + incr;
  filloutrec := unzip_ok;
 END;
END;

{**************** Get first entry from ZIP file ********************}
FUNCTION GetFirstInZip ( zipfilename : pchar;VAR zprec : tZipRec ) : integer;
VAR bufstart, headerstart, start : longint;
    err, i : integer;
    mainh : pmainheader;
    f : file;
    extra : word;   {Extra bytes for saving File!}

BEGIN
 WITH zprec DO BEGIN
  assign ( f, zipfilename );
  filemode := 0;  {Others may read or write};
  {$I-}
  reset ( f, 1 );
  {$I+}
  IF ioresult <> 0 THEN BEGIN
    GetFirstInZip := unzip_FileError;
    exit
  END;
  size := filesize ( f );
  IF size = 0 THEN BEGIN
    GetFirstInZip := unzip_FileError;
    {$I-}
    close ( f );
    {$I+}
    exit
  END;
  bufsize := 4096;     {in 4k-blocks}
  IF size > bufsize THEN BEGIN
    bufstart := size -bufsize;
  END ELSE BEGIN
    bufstart := 0;
    bufsize := size;
  END;
  getmem ( buf, bufsize + 1 );     {#0 at the end of filemname}

  {Search from back of file to central directory start}
  start := -1;    {Nothing found}
  REPEAT
    {$I-}
    seek ( f, bufstart );
    {$I+}
    IF ioresult <> 0 THEN BEGIN
      GetFirstInZip := unzip_FileError;
      freeMem ( buf, bufsize + 1 );
      buf := NIL;
      {$I-}
      close ( f );
      {$I+}
      exit
    END;
    {$I-}
    blockread ( f, buf^, bufsize, err );
    {$I+}
    IF ( ioresult <> 0 ) OR ( err <> bufsize ) THEN BEGIN
      GetFirstInZip := unzip_FileError;
      freeMem ( buf, bufsize + 1 );
      buf := NIL;
      {$I-}
      close ( f );
      {$I+}
      exit
    END;

    IF bufstart = 0 THEN start := maxlongint;{Break}

    FOR i := bufsize -22 DOWNTO 0 DO BEGIN  {Search buffer backwards}
      IF ( buf^ [ i ] = 'P' ) AND ( buf^ [ i + 1 ] = 'K' ) AND ( buf^ [ i + 2 ] = #5 ) AND ( buf^ [ i + 3 ] = #6 )
      THEN BEGIN                         {Header found!!!}
        start := bufstart + i;
        break;
      END;
    END;

    IF start = -1 THEN BEGIN               {Nothing found yet}
      dec ( bufstart, bufsize -22 );          {Full header in buffer!}
      IF bufstart < 0 THEN bufstart := 0;
    END;
  UNTIL start >= 0;
  IF ( start = maxlongint ) THEN BEGIN       {Nothing found}
    GetFirstInZip := unzip_FileError;
    freeMem ( buf, bufsize + 1 );
    buf := NIL;
    {$I-}
    close ( f );
    {$I+}
    exit
  END;
  mainh := pmainheader ( @buf^ [ start -bufstart ] );
  headerstart := mainh^.headstart;
  localstart := 0;
  freeMem ( buf, bufsize + 1 );
  IF ( localstart + sizeof ( theader ) > start ) THEN BEGIN
    buf := NIL;
    GetFirstInZip := unzip_InternalError;
    {$I-}
    close ( f );
    {$I+}
    exit
  END;
  bufstart := headerstart;
  start := start -headerstart + 4; {size for central dir,Including main header signature}
  IF start >= maxbufsize THEN BEGIN
    bufsize := maxbufsize; {Max buffer size, limit of around 1000 items!}
    extra := sizeof ( file ) {Save file information for later reading!}
  END ELSE BEGIN
    bufsize := start;
    extra := 0
  END;
  getmem ( buf, bufsize + 1 + extra );
  {$I-}
  seek ( f, bufstart );
  {$I+}
  IF ioresult <> 0 THEN BEGIN
    GetFirstInZip := unzip_FileError;
    freeMem ( buf, bufsize + 1 + extra );
    buf := NIL;
    {$I-}
    close ( f );
    {$I+}
    exit
  END;
  {$I-}
  blockread ( f, buf^, bufsize, err );  {Read in full central dir, up to maxbufsize Bytes}
  {$I+}
  IF ioresult <> 0 THEN BEGIN
    GetFirstInZip := unzip_FileError;
    freeMem ( buf, bufsize + 1 + extra );
    buf := NIL;
    {$I-}
    close ( f );
    {$I+}
    exit
  END;
  IF extra = 0 THEN
  {$I-} close ( f ) {$I+}
    ELSE move ( f, buf^ [ bufsize + 1 ], extra );  {Save file info!}
  err := filloutRec ( zprec );
  IF err <> unzip_ok THEN BEGIN
    CloseZipFile ( zprec );
    GetFirstInZip := err;
    exit
  END;
  GetFirstInZip := err;
 END;
END;

{**************** Get next entry from ZIP file ********************}
FUNCTION GetNextInZip ( VAR Zprec : tZiprec ) : integer;
VAR err : integer;
BEGIN
 WITH zprec DO BEGIN
  IF ( buf <> NIL ) THEN BEGIN  {Main Header at the end}
    err := filloutRec ( zprec );
    IF err <> unzip_ok THEN BEGIN
      CloseZipFile ( ZPRec );
    END;
    GetNextInZip := err;
  END ELSE GetNextInZip := unzip_NoMoreItems;
 END
END;

{**************** VERY simple test for zip file ********************}
FUNCTION isZip ( filename : pchar ) : boolean;
VAR
    myname : tdirtype;
    l, err : integer;
    f : file;
    buf : ARRAY [ 0..4 ] of char;
    oldcurdir : string{$ifndef BIT32} [ 80 ]{$endif};

BEGIN
  filemode := 0;
  {$I-}
  getdir ( 0, oldcurdir );
  {$I+}
  err := ioresult;
  isZip := FALSE;
  IF ( strscan ( filename, '.' ) <> NIL )
    AND ( strpos ( filename, '.exe' ) = NIL ) THEN BEGIN
    strcopy ( myname, filename );
    l := strlen ( myname );
    IF myname [ l -1 ] = DirSep THEN myname [ l -1 ] := #0;
    {$I-}
    chdir ( Strpas ( myname ) );
    {$I+}
    IF ioresult <> 0 THEN BEGIN
      assign ( f, Strpas ( myname ) );
      filemode := 0;  {Others may read or write};
      {$I-}
      reset ( f, 1 );
      {$I+}
      IF ioresult = 0 THEN BEGIN
        {$I-}
        blockread ( f, buf, 4, err );
        {$I+}
        IF ( ioresult = 0 ) THEN BEGIN
          IF ( err = 4 ) AND ( buf [ 0 ] = 'P' ) AND ( buf [ 1 ] = 'K' )
            AND ( buf [ 2 ] = #3 ) AND ( buf [ 3 ] = #4 ) THEN isZip := TRUE
        END;
        {$I-}
        close ( f );
        {$I+}
        err := ioresult;  {only clears ioresult variable}
      END;
    END;
  END;
  {$I-}
  chdir ( oldcurdir );
  {$I+}
  err := ioresult;
END;

{**************** free ZIP buffers ********************}
PROCEDURE CloseZipFile ( VAR Zprec : tZiprec );  {Only free buffer, file only open in Getfirstinzip}
VAR
    f : file;
    extra : word;
BEGIN
 WITH zprec DO BEGIN
  IF buf <> NIL THEN BEGIN
    IF ( bufsize = maxbufsize ) THEN BEGIN       {Caution: header bigger than 64k!}
      extra := sizeof ( file );
      move ( buf^ [ bufsize + 1 ], f, extra );   {Restore file}
      {$I-}
      close ( f );
      {$I+}
      IF ioresult <> 0 THEN ;
    END ELSE extra := 0;
    freemem ( buf, bufsize + 1 + extra );
    buf := NIL
  END;
 END
END;
{***************************************************************************}
{***************************************************************************}
{********** routines by the African Chief **********************************}
{***************************************************************************}
{***************************************************************************}
{$ifndef Delphi}
FUNCTION FileExists ( CONST fname : string ) : boolean; {simple fileexist function}
VAR
f : file;
i : byte;
BEGIN
    i := filemode;
    filemode := 0;
    assign ( f, fname );
    {$i-}
    Reset ( f, 1 );
    filemode := i;
    FileExists := ioresult = 0;
    Close ( f ); IF ioresult <> 0 THEN;
    {$i+}
END;
{$endif Delphi}

PROCEDURE DummyReport ( Retcode : longint;Rec : pReportRec );
{dummy report procedure}
BEGIN
END;

FUNCTION DummyQuestion( Rec : pReportRec ) : Boolean;
{dummy question procedure}
begin
  DummyQuestion:=true;
end;

FUNCTION Matches ( s : String;CONST main : string ) : Boolean;
{rudimentary matching function;
 accepts only '', '*.*', 'XXX.*' or '*.XXX'
}
FUNCTION extensiononly ( CONST s : string ) : string;{return just the extension}
VAR i : integer;
BEGIN
   extensiononly := '';
   i := pos ( '.', s );
   IF i = 0 THEN exit;
   extensiononly := copy ( s, succ ( i ), length ( s ) );
END;

FUNCTION nameonly ( CONST s : string ) : string;{return just the name}
VAR i : integer;
BEGIN
   nameonly := s;
   i := pos ( '.', s );
   IF i = 0 THEN exit;
   nameonly := copy ( s, 1, pred ( i ) );
END;
{!!!!!}
VAR
b : boolean;
i : integer;
BEGIN
   Matches := TRUE;
   IF ( s = '' ) OR ( s = AllFiles ) THEN exit; {'' or '*.*' = all files match}
   s := upper ( s );
   b := copy ( s, 1, 2 ) = '*.';  {e.g., *.PAS}
   IF b THEN BEGIN
      delete ( s, 1, 2 );
      Matches := s = extensiononly ( upper ( main ) );
   END ELSE BEGIN
      i := length ( s );
      b := s [ i ] = '*'; {e.g. TEST.*}
      IF b THEN BEGIN
         IF s [ pred ( i ) ] = '.' THEN delete ( s, pred ( i ), 2 );
         i := length ( s );
         IF s [ i ] in [ '*', '?' ] THEN dec ( i );{e.g. TEST*.*}
         Matches := Copy ( s, 1, i ) = Copy ( nameonly ( upper ( main ) ), 1, i );
      END ELSE Matches := s = upper ( main );
   END;
END;  { Matches }
{****************************************************}
FUNCTION FileUnzip ( SourceZipFile, TargetDirectory, FileSpecs : pChar;
 Report : UnzipReportProc;Question : UnzipQuestionProc ) : integer;
VAR
    rc : integer;
    r : tziprec;
    buf,
    thename,
    target : ARRAY [ 0..tFSize ] of char;
    Count : integer;
    rSize, cSize : longint;
    s : string [ 255 ];

BEGIN
{$IFDEF FPC}
  IF not assigned(Report) THEN
   Report := @DummyReport;
  IF not assigned(Question) THEN
   Question := @DummyQuestion;
{$ELSE}
  IF @Report = nil THEN
   Report := DummyReport;
  IF @Question = nil THEN
   Question := DummyQuestion;
{$ENDIF}

  Count := 0;
  rSize := 0;
  cSize := 0;
  FileUnzip := unzip_MissingParameter;
  IF ( StrPas ( SourceZipFile ) = '' ) OR ( StrPas ( TargetDirectory ) = '' ) THEN Exit;

  Strcopy ( thename, SourceZipFile );
  Strcopy ( target, TargetDirectory );
  IF ( target [ 0 ] <> #0 ) AND ( target [ strlen ( target ) -1 ] <> DirSep )
  THEN strcat ( target, DirSep );
  FileUnzip := unzip_NotZipFile;
  IF NOT iszip ( thename ) THEN exit;

  FillChar ( ZipRec, Sizeof ( ZipRec ), #0 );

  WITH ZipRec DO BEGIN
       IsaDir := FALSE;
       strcopy ( FileName, thename );
       Size := UnZipSize ( SourceZipFile, CompressSize );
       IF Size = 0 THEN ratio := 0 ELSE
       Ratio := 100 -Round ( ( CompressSize / Size ) * 100 );
       Status := unzip_starting;
       Report ( Status, @ZipRec );
  END; {start of ZIP file}

  ZipReport := Report;

  rc := getfirstinzip ( thename, r );
  WHILE ( rc = unzip_ok )
  DO BEGIN
   IF ( Matches ( StrPas ( FileSpecs ), Strpas ( R.FileName ) ) )
   THEN BEGIN
      Inc ( rSize, r.Size );
      Inc ( cSize, r.CompressSize );

      strcopy ( buf, target );
      IF NoRecurseDirs  { no recursion }
      THEN BEGIN
          s := StripPath ( Strpas ( r.filename ) ) + #0;
          Strcat ( buf, @s [ 1 ] );
      END ELSE strcat ( buf, r.filename );


      WITH ZipRec DO BEGIN { report start of file }
           s := StrPas ( Buf );
           IsaDir := s [ length ( s ) ] = DirSep;
           Time := r.Time;
           Size := r.Size;
           CompressSize := r.CompressSize;
           strcopy ( FileName, buf );
           PackMethod := r.PackMethod;
           Attr := r.Attr;
           IF Size = 0 THEN ratio := 0 ELSE
           Ratio := 100 -Round ( ( CompressSize /Size ) * 100 );
           Status := file_starting;
           IF ( IsaDir ) AND ( NoRecurseDirs )
           THEN {} ELSE
           ZipReport ( Status, @ZipRec );
      END;  { start of file }

      IF ( FileExists ( StrPas ( buf ) ) )
      AND ( Question ( @ZipRec ) = FALSE )
      THEN BEGIN
         rc := unzip_ok;              { we are okay }
         WITH ZipRec DO BEGIN
           Status := file_unzipping;
           PackMethod := 9;           { skipped }
           ZipReport ( Size, @ZipRec );  { report uncompressed size }
         END;
      END ELSE BEGIN
          rc := unzipfile ( thename, buf, r.headeroffset, 0,
          27 ); {Escape interrupts}
      END;

      IF rc = unzip_ok
      THEN BEGIN
         Inc ( Count );
         WITH ZipRec DO BEGIN   { report end of file }
            Status := file_completed;
            IF ( IsaDir ) AND ( NoRecurseDirs )
            THEN {} ELSE
            ZipReport ( Status, @ZipRec );
         END; { end of file }
      END ELSE BEGIN
           ZipRec.Status := file_failure; {error}
           CASE rc of
                unzip_CRCErr,
                unzip_WriteErr,
                unzip_Encrypted,
                unzip_NotSupported : ZipReport ( rc, @ZipRec );

                unzip_ReadErr, unzip_Userabort,
                unzip_FileError, unzip_InternalError,
                unzip_InUse, unzip_ZipFileErr :
                BEGIN
                    ZipRec.Status := unzip_SeriousError;
                    FileUnzip := unzip_SeriousError;   {Serious error, force abort}
                    ZipReport ( unzip_SeriousError, @ZipRec );
                    closezipfile ( r );
                    ZipReport := NIL;
                    ZipQuestion := NIL;
                    exit;
                END;
           END; {case rc}
           Continue;
           {rc:=getnextinzip(r);}
        END; {else}
    END; { if Matches }
      rc := getnextinzip ( r );
  END; {while }

  closezipfile ( r );               {Free memory used for central directory info}

  WITH ZipRec DO BEGIN { report end of ZIP file }
       Time := -1;
       Attr := -1;
       PackMethod := 0;
       Size := rSize;
       CompressSize := cSize;
       strcopy ( FileName, thename );
       IF Size = 0 THEN ratio := 0 ELSE
       Ratio := 100 -Round ( ( CompressSize /Size ) * 100 );
       Status := unzip_completed;
       ZipReport ( Status, @ZipRec );
  END; { end of ZIP file }

  ZipReport := NIL;
  ZipQuestion := NIL;
  FileUnzip := Count;
END; { FileUnzip }
{***************************************************************************}
FUNCTION FileUnzipEx ( SourceZipFile, TargetDirectory, FileSpecs : pChar ) : integer;
BEGIN
  FileUnzipEx :=
  FileUnzip ( SourceZipFile, TargetDirectory, FileSpecs, ZipReport, ZipQuestion );
END; { FileUnzipEx }
{***************************************************************************}
FUNCTION Viewzip ( SourceZipFile, FileSpecs : pChar; Report : UnzipReportProc ) : integer;
VAR
    rc : integer;
    r : tziprec;
    thename : ARRAY [ 0..tFSize ] of char;
    Count : integer;
    rSize, cSize : longint;

BEGIN
  Count := 0;
  rSize := 0;
  cSize := 0;
  Viewzip := unzip_MissingParameter;
{$IFDEF FPC}
  IF ( StrPas ( SourceZipFile ) = '' ) or
     not assigned(Report) THEN
   exit;
{$ELSE}
  IF ( StrPas ( SourceZipFile ) = '' ) OR ( @Report = NIL ) THEN Exit;
{$ENDIF}

  Strcopy ( thename, SourceZipFile );
  ViewZip := unzip_NotZipFile;
  IF NOT iszip ( thename ) THEN exit;
  FillChar ( ZipRec, Sizeof ( ZipRec ), #0 );

  rc := getfirstinzip ( thename, r );
  WHILE ( rc = unzip_ok )
  DO BEGIN
   IF ( Matches ( StrPas ( FileSpecs ), Strpas ( R.FileName ) ) ) THEN BEGIN
      Inc ( rSize, r.Size );
      Inc ( cSize, r.CompressSize );
      WITH ZipRec DO BEGIN
           Time := r.Time;
           Size := r.Size;
           CompressSize := r.CompressSize;
           strcopy ( FileName, r.Filename );
           PackMethod := r.PackMethod;
           Attr := r.Attr;
           IF Size = 0 THEN ratio := 0 ELSE
           Ratio := 100 -Round ( ( CompressSize /Size ) * 100 );
      END;
      Inc ( Count );
      Report ( rc, @ZipRec );
   END; {matches}
      rc := getnextinzip ( r );
  END; {while }
  closezipfile ( r );

  WITH ZipRec DO BEGIN
       Time := -1;
       Attr := -1;
       PackMethod := 0;
       Size := rSize;
       CompressSize := cSize;
       strcopy ( FileName, thename );
       IF Size = 0 THEN ratio := 0 ELSE
       Ratio := 100 -Round ( ( CompressSize /Size ) * 100 );
  END;
  Report ( Count, @ZipRec );
  ViewZip := Count;
END; { ViewZip }
{***************************************************************************}
FUNCTION UnZipSize ( SourceZipFile : pChar;VAR Compressed : Longint ) : longint;
VAR
    rc : integer;
    r : tziprec;
    thename : ARRAY [ 0..tFSize ] of char;
    Count : longint;
    f : file;

BEGIN
  Compressed := 0;
  UnZipSize := 0;
  IF ( StrPas ( SourceZipFile ) = '' ) THEN Exit;
  System.Assign ( f, StrPas ( SourceZipFile ) );
  count := filemode;
  filemode := 0;
  {$i-}
  Reset ( f, 1 );
  filemode := count;
  IF ioresult <> 0 THEN exit;
  Count := filesize ( f );
  close ( f );
  UnZipSize := count;
  Compressed := count;
  Strcopy ( thename, SourceZipFile );
  IF NOT iszip ( thename ) THEN exit;
  Count := 0;
  Compressed := 0;
  rc := getfirstinzip ( thename, r );
  WHILE ( rc = unzip_ok )
  DO BEGIN
      Inc ( Count, r.Size );
      Inc ( Compressed, r.CompressSize );
      rc := getnextinzip ( r );
  END; {while }
  closezipfile ( r );
  UnZipSize := Count;
END; { UnZipSize }
{***************************************************************************}
FUNCTION  SetUnZipReportProc ( aProc : UnzipReportProc ) : Pointer;
BEGIN
{$IFDEF FPC}
   SetUnZipReportProc := ZipReport; {save and return original}
{$ELSE}
   SetUnZipReportProc := @ZipReport; {save and return original}
{$ENDIF}
   ZipReport  := aProc;
END; { SetUnZipReportProc }
{***************************************************************************}
FUNCTION  SetUnZipQuestionProc ( aProc : UnzipQuestionProc ) : Pointer;
BEGIN
{$IFDEF FPC}
  SetUnZipQuestionProc := ZipQuestion;  {save and return original}
{$ELSE}
  SetUnZipQuestionProc := @ZipQuestion;  {save and return original}
{$ENDIF}
  ZipQuestion := aProc;
END; { SetUnZipQuestionProc }
{***************************************************************************}
FUNCTION SetNoRecurseDirs ( DontRecurse : Boolean ) : Boolean;
BEGIN
   SetNoRecurseDirs := NoRecurseDirs;
   NoRecurseDirs := DontRecurse;
END; { SetNoRecurseDirs }
{***************************************************************************}
{***************************************************************************}
PROCEDURE ChfUnzip_Init;
BEGIN
   slide := NIL;       {unused}
  if inuse then; { to remove warning }
  SetUnZipReportProc ( NIL );
  SetUnZipQuestionProc ( NIL );
  SetNoRecurseDirs ( FALSE );
END;
{***************************************************************************}
{***************************************************************************}
{***************************************************************************}
BEGIN
   ChfUnzip_Init;
END.