files.c

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/*
===========================================================================
Copyright (C) 1999-2005 Id Software, Inc.

This file is part of Quake III Arena source code.

Quake III Arena source code is free software; you can redistribute it
and/or modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the License,
or (at your option) any later version.

Quake III Arena source code is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with Foobar; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
===========================================================================
*/
/*****************************************************************************
 * name:        files.c
 *
 * desc:        handle based filesystem for Quake III Arena 
 *
 * $Archive: /MissionPack/code/qcommon/files.c $
 *
 *****************************************************************************/


#include "../game/q_shared.h"
#include "qcommon.h"
#include "unzip.h"

/*
=============================================================================

QUAKE3 FILESYSTEM

All of Quake's data access is through a hierarchical file system, but the contents of 
the file system can be transparently merged from several sources.

A "qpath" is a reference to game file data.  MAX_ZPATH is 256 characters, which must include
a terminating zero. "..", "\\", and ":" are explicitly illegal in qpaths to prevent any
references outside the quake directory system.

The "base path" is the path to the directory holding all the game directories and usually
the executable.  It defaults to ".", but can be overridden with a "+set fs_basepath c:\quake3"
command line to allow code debugging in a different directory.  Basepath cannot
be modified at all after startup.  Any files that are created (demos, screenshots,
etc) will be created reletive to the base path, so base path should usually be writable.

The "cd path" is the path to an alternate hierarchy that will be searched if a file
is not located in the base path.  A user can do a partial install that copies some
data to a base path created on their hard drive and leave the rest on the cd.  Files
are never writen to the cd path.  It defaults to a value set by the installer, like
"e:\quake3", but it can be overridden with "+set ds_cdpath g:\quake3".

If a user runs the game directly from a CD, the base path would be on the CD.  This
should still function correctly, but all file writes will fail (harmlessly).

The "home path" is the path used for all write access. On win32 systems we have "base path"
== "home path", but on *nix systems the base installation is usually readonly, and
"home path" points to ~/.q3a or similar

The user can also install custom mods and content in "home path", so it should be searched
along with "home path" and "cd path" for game content.


The "base game" is the directory under the paths where data comes from by default, and
can be either "baseq3" or "demoq3".

The "current game" may be the same as the base game, or it may be the name of another
directory under the paths that should be searched for files before looking in the base game.
This is the basis for addons.

Clients automatically set the game directory after receiving a gamestate from a server,
so only servers need to worry about +set fs_game.

No other directories outside of the base game and current game will ever be referenced by
filesystem functions.

To save disk space and speed loading, directory trees can be collapsed into zip files.
The files use a ".pk3" extension to prevent users from unzipping them accidentally, but
otherwise the are simply normal uncompressed zip files.  A game directory can have multiple
zip files of the form "pak0.pk3", "pak1.pk3", etc.  Zip files are searched in decending order
from the highest number to the lowest, and will always take precedence over the filesystem.
This allows a pk3 distributed as a patch to override all existing data.

Because we will have updated executables freely available online, there is no point to
trying to restrict demo / oem versions of the game with code changes.  Demo / oem versions
should be exactly the same executables as release versions, but with different data that
automatically restricts where game media can come from to prevent add-ons from working.

After the paths are initialized, quake will look for the product.txt file.  If not
found and verified, the game will run in restricted mode.  In restricted mode, only 
files contained in demoq3/pak0.pk3 will be available for loading, and only if the zip header is
verified to not have been modified.  A single exception is made for q3config.cfg.  Files
can still be written out in restricted mode, so screenshots and demos are allowed.
Restricted mode can be tested by setting "+set fs_restrict 1" on the command line, even
if there is a valid product.txt under the basepath or cdpath.

If not running in restricted mode, and a file is not found in any local filesystem,
an attempt will be made to download it and save it under the base path.

If the "fs_copyfiles" cvar is set to 1, then every time a file is sourced from the cd
path, it will be copied over to the base path.  This is a development aid to help build
test releases and to copy working sets over slow network links.

File search order: when FS_FOpenFileRead gets called it will go through the fs_searchpaths
structure and stop on the first successful hit. fs_searchpaths is built with successive
calls to FS_AddGameDirectory

Additionaly, we search in several subdirectories:
current game is the current mode
base game is a variable to allow mods based on other mods
(such as baseq3 + missionpack content combination in a mod for instance)
BASEGAME is the hardcoded base game ("baseq3")

e.g. the qpath "sound/newstuff/test.wav" would be searched for in the following places:

home path + current game's zip files
home path + current game's directory
base path + current game's zip files
base path + current game's directory
cd path + current game's zip files
cd path + current game's directory

home path + base game's zip file
home path + base game's directory
base path + base game's zip file
base path + base game's directory
cd path + base game's zip file
cd path + base game's directory

home path + BASEGAME's zip file
home path + BASEGAME's directory
base path + BASEGAME's zip file
base path + BASEGAME's directory
cd path + BASEGAME's zip file
cd path + BASEGAME's directory

server download, to be written to home path + current game's directory


The filesystem can be safely shutdown and reinitialized with different
basedir / cddir / game combinations, but all other subsystems that rely on it
(sound, video) must also be forced to restart.

Because the same files are loaded by both the clip model (CM_) and renderer (TR_)
subsystems, a simple single-file caching scheme is used.  The CM_ subsystems will
load the file with a request to cache.  Only one file will be kept cached at a time,
so any models that are going to be referenced by both subsystems should alternate
between the CM_ load function and the ref load function.

TODO: A qpath that starts with a leading slash will always refer to the base game, even if another
game is currently active.  This allows character models, skins, and sounds to be downloaded
to a common directory no matter which game is active.

How to prevent downloading zip files?
Pass pk3 file names in systeminfo, and download before FS_Restart()?

Aborting a download disconnects the client from the server.

How to mark files as downloadable?  Commercial add-ons won't be downloadable.

Non-commercial downloads will want to download the entire zip file.
the game would have to be reset to actually read the zip in

Auto-update information

Path separators

Casing

  separate server gamedir and client gamedir, so if the user starts
  a local game after having connected to a network game, it won't stick
  with the network game.

  allow menu options for game selection?

Read / write config to floppy option.

Different version coexistance?

When building a pak file, make sure a q3config.cfg isn't present in it,
or configs will never get loaded from disk!

  todo:

  downloading (outside fs?)
  game directory passing and restarting

=============================================================================

*/

#define DEMOGAME            "demota"

// every time a new demo pk3 file is built, this checksum must be updated.
// the easiest way to get it is to just run the game and see what it spits out
#define DEMO_PAK_CHECKSUM   437558517u

// if this is defined, the executable positively won't work with any paks other
// than the demo pak, even if productid is present.  This is only used for our
// last demo release to prevent the mac and linux users from using the demo
// executable with the production windows pak before the mac/linux products
// hit the shelves a little later
// NOW defined in build files
//#define PRE_RELEASE_TADEMO

#define MAX_ZPATH           256
#define MAX_SEARCH_PATHS    4096
#define MAX_FILEHASH_SIZE   1024

typedef struct fileInPack_s {
    char                    *name;      // name of the file
    unsigned long           pos;        // file info position in zip
    struct  fileInPack_s*   next;       // next file in the hash
} fileInPack_t;

typedef struct {
    char            pakFilename[MAX_OSPATH];    // c:\quake3\baseq3\pak0.pk3
    char            pakBasename[MAX_OSPATH];    // pak0
    char            pakGamename[MAX_OSPATH];    // baseq3
    unzFile         handle;                     // handle to zip file
    int             checksum;                   // regular checksum
    int             pure_checksum;              // checksum for pure
    int             numfiles;                   // number of files in pk3
    int             referenced;                 // referenced file flags
    int             hashSize;                   // hash table size (power of 2)
    fileInPack_t*   *hashTable;                 // hash table
    fileInPack_t*   buildBuffer;                // buffer with the filenames etc.
} pack_t;

typedef struct {
    char        path[MAX_OSPATH];       // c:\quake3
    char        gamedir[MAX_OSPATH];    // baseq3
} directory_t;

typedef struct searchpath_s {
    struct searchpath_s *next;

    pack_t      *pack;      // only one of pack / dir will be non NULL
    directory_t *dir;
} searchpath_t;

static  char        fs_gamedir[MAX_OSPATH]; // this will be a single file name with no separators
static  cvar_t      *fs_debug;
static  cvar_t      *fs_homepath;
static  cvar_t      *fs_basepath;
static  cvar_t      *fs_basegame;
static  cvar_t      *fs_cdpath;
static  cvar_t      *fs_copyfiles;
static  cvar_t      *fs_gamedirvar;
static  cvar_t      *fs_restrict;
static  searchpath_t    *fs_searchpaths;
static  int         fs_readCount;           // total bytes read
static  int         fs_loadCount;           // total files read
static  int         fs_loadStack;           // total files in memory
static  int         fs_packFiles;           // total number of files in packs

static int fs_fakeChkSum;
static int fs_checksumFeed;

typedef union qfile_gus {
    FILE*       o;
    unzFile     z;
} qfile_gut;

typedef struct qfile_us {
    qfile_gut   file;
    qboolean    unique;
} qfile_ut;

typedef struct {
    qfile_ut    handleFiles;
    qboolean    handleSync;
    int         baseOffset;
    int         fileSize;
    int         zipFilePos;
    qboolean    zipFile;
    qboolean    streamed;
    char        name[MAX_ZPATH];
} fileHandleData_t;

static fileHandleData_t fsh[MAX_FILE_HANDLES];

// TTimo - https://zerowing.idsoftware.com/bugzilla/show_bug.cgi?id=540
// wether we did a reorder on the current search path when joining the server
static qboolean fs_reordered;

// never load anything from pk3 files that are not present at the server when pure
static int      fs_numServerPaks;
static int      fs_serverPaks[MAX_SEARCH_PATHS];                // checksums
static char     *fs_serverPakNames[MAX_SEARCH_PATHS];           // pk3 names

// only used for autodownload, to make sure the client has at least
// all the pk3 files that are referenced at the server side
static int      fs_numServerReferencedPaks;
static int      fs_serverReferencedPaks[MAX_SEARCH_PATHS];          // checksums
static char     *fs_serverReferencedPakNames[MAX_SEARCH_PATHS];     // pk3 names

// last valid game folder used
char lastValidBase[MAX_OSPATH];
char lastValidGame[MAX_OSPATH];

// productId: This file is copyright 1999 Id Software, and may not be duplicated except during a licensed installation of the full commercial version of Quake 3:Arena
static byte fs_scrambledProductId[152] = {
220, 129, 255, 108, 244, 163, 171, 55, 133, 65, 199, 36, 140, 222, 53, 99, 65, 171, 175, 232, 236, 193, 210, 250, 169, 104, 231, 231, 21, 201, 170, 208, 135, 175, 130, 136, 85, 215, 71, 23, 96, 32, 96, 83, 44, 240, 219, 138, 184, 215, 73, 27, 196, 247, 55, 139, 148, 68, 78, 203, 213, 238, 139, 23, 45, 205, 118, 186, 236, 230, 231, 107, 212, 1, 10, 98, 30, 20, 116, 180, 216, 248, 166, 35, 45, 22, 215, 229, 35, 116, 250, 167, 117, 3, 57, 55, 201, 229, 218, 222, 128, 12, 141, 149, 32, 110, 168, 215, 184, 53, 31, 147, 62, 12, 138, 67, 132, 54, 125, 6, 221, 148, 140, 4, 21, 44, 198, 3, 126, 12, 100, 236, 61, 42, 44, 251, 15, 135, 14, 134, 89, 92, 177, 246, 152, 106, 124, 78, 118, 80, 28, 42
};

#ifdef FS_MISSING
FILE*       missingFiles = NULL;
#endif

/*
==============
FS_Initialized
==============
*/

qboolean FS_Initialized() {
    return (fs_searchpaths != NULL);
}

/*
=================
FS_PakIsPure
=================
*/
qboolean FS_PakIsPure( pack_t *pack ) {
    int i;

    if ( fs_numServerPaks ) {
        for ( i = 0 ; i < fs_numServerPaks ; i++ ) {
            // FIXME: also use hashed file names
            // NOTE TTimo: a pk3 with same checksum but different name would be validated too
            //   I don't see this as allowing for any exploit, it would only happen if the client does manips of it's file names 'not a bug'
            if ( pack->checksum == fs_serverPaks[i] ) {
                return qtrue;       // on the aproved list
            }
        }
        return qfalse;  // not on the pure server pak list
    }
    return qtrue;
}


/*
=================
FS_LoadStack
return load stack
=================
*/
int FS_LoadStack()
{
    return fs_loadStack;
}
                      
/*
================
return a hash value for the filename
================
*/
static long FS_HashFileName( const char *fname, int hashSize ) {
    int     i;
    long    hash;
    char    letter;

    hash = 0;
    i = 0;
    while (fname[i] != '\0') {
        letter = tolower(fname[i]);
        if (letter =='.') break;                // don't include extension
        if (letter =='\\') letter = '/';        // damn path names
        if (letter == PATH_SEP) letter = '/';       // damn path names
        hash+=(long)(letter)*(i+119);
        i++;
    }
    hash = (hash ^ (hash >> 10) ^ (hash >> 20));
    hash &= (hashSize-1);
    return hash;
}

static fileHandle_t FS_HandleForFile(void) {
    int     i;

    for ( i = 1 ; i < MAX_FILE_HANDLES ; i++ ) {
        if ( fsh[i].handleFiles.file.o == NULL ) {
            return i;
        }
    }
    Com_Error( ERR_DROP, "FS_HandleForFile: none free" );
    return 0;
}

static FILE *FS_FileForHandle( fileHandle_t f ) {
    if ( f < 0 || f > MAX_FILE_HANDLES ) {
        Com_Error( ERR_DROP, "FS_FileForHandle: out of reange" );
    }
    if (fsh[f].zipFile == qtrue) {
        Com_Error( ERR_DROP, "FS_FileForHandle: can't get FILE on zip file" );
    }
    if ( ! fsh[f].handleFiles.file.o ) {
        Com_Error( ERR_DROP, "FS_FileForHandle: NULL" );
    }
    
    return fsh[f].handleFiles.file.o;
}

void    FS_ForceFlush( fileHandle_t f ) {
    FILE *file;

    file = FS_FileForHandle(f);
    setvbuf( file, NULL, _IONBF, 0 );
}

/*
================
FS_filelength

If this is called on a non-unique FILE (from a pak file),
it will return the size of the pak file, not the expected
size of the file.
================
*/
int FS_filelength( fileHandle_t f ) {
    int     pos;
    int     end;
    FILE*   h;

    h = FS_FileForHandle(f);
    pos = ftell (h);
    fseek (h, 0, SEEK_END);
    end = ftell (h);
    fseek (h, pos, SEEK_SET);

    return end;
}

/*
====================
FS_ReplaceSeparators

Fix things up differently for win/unix/mac
====================
*/
static void FS_ReplaceSeparators( char *path ) {
    char    *s;

    for ( s = path ; *s ; s++ ) {
        if ( *s == '/' || *s == '\\' ) {
            *s = PATH_SEP;
        }
    }
}

/*
===================
FS_BuildOSPath

Qpath may have either forward or backwards slashes
===================
*/
char *FS_BuildOSPath( const char *base, const char *game, const char *qpath ) {
    char    temp[MAX_OSPATH];
    static char ospath[2][MAX_OSPATH];
    static int toggle;
    
    toggle ^= 1;        // flip-flop to allow two returns without clash

    if( !game || !game[0] ) {
        game = fs_gamedir;
    }

    Com_sprintf( temp, sizeof(temp), "/%s/%s", game, qpath );
    FS_ReplaceSeparators( temp );   
    Com_sprintf( ospath[toggle], sizeof( ospath[0] ), "%s%s", base, temp );
    
    return ospath[toggle];
}


/*
============
FS_CreatePath

Creates any directories needed to store the given filename
============
*/
static qboolean FS_CreatePath (char *OSPath) {
    char    *ofs;
    
    // make absolutely sure that it can't back up the path
    // FIXME: is c: allowed???
    if ( strstr( OSPath, ".." ) || strstr( OSPath, "::" ) ) {
        Com_Printf( "WARNING: refusing to create relative path \"%s\"\n", OSPath );
        return qtrue;
    }

    for (ofs = OSPath+1 ; *ofs ; ofs++) {
        if (*ofs == PATH_SEP) { 
            // create the directory
            *ofs = 0;
            Sys_Mkdir (OSPath);
            *ofs = PATH_SEP;
        }
    }
    return qfalse;
}

/*
=================
FS_CopyFile

Copy a fully specified file from one place to another
=================
*/
static void FS_CopyFile( char *fromOSPath, char *toOSPath ) {
    FILE    *f;
    int     len;
    byte    *buf;

    Com_Printf( "copy %s to %s\n", fromOSPath, toOSPath );

    if (strstr(fromOSPath, "journal.dat") || strstr(fromOSPath, "journaldata.dat")) {
        Com_Printf( "Ignoring journal files\n");
        return;
    }

    f = fopen( fromOSPath, "rb" );
    if ( !f ) {
        return;
    }
    fseek (f, 0, SEEK_END);
    len = ftell (f);
    fseek (f, 0, SEEK_SET);

    // we are using direct malloc instead of Z_Malloc here, so it
    // probably won't work on a mac... Its only for developers anyway...
    buf = malloc( len );
    if (fread( buf, 1, len, f ) != len)
        Com_Error( ERR_FATAL, "Short read in FS_Copyfiles()\n" );
    fclose( f );

    if( FS_CreatePath( toOSPath ) ) {
        return;
    }

    f = fopen( toOSPath, "wb" );
    if ( !f ) {
        return;
    }
    if (fwrite( buf, 1, len, f ) != len)
        Com_Error( ERR_FATAL, "Short write in FS_Copyfiles()\n" );
    fclose( f );
    free( buf );
}

/*
===========
FS_Remove

===========
*/
static void FS_Remove( const char *osPath ) {
    remove( osPath );
}

/*
================
FS_FileExists

Tests if the file exists in the current gamedir, this DOES NOT
search the paths.  This is to determine if opening a file to write
(which always goes into the current gamedir) will cause any overwrites.
NOTE TTimo: this goes with FS_FOpenFileWrite for opening the file afterwards
================
*/
qboolean FS_FileExists( const char *file )
{
    FILE *f;
    char *testpath;

    testpath = FS_BuildOSPath( fs_homepath->string, fs_gamedir, file );

    f = fopen( testpath, "rb" );
    if (f) {
        fclose( f );
        return qtrue;
    }
    return qfalse;
}

/*
================
FS_SV_FileExists

Tests if the file exists 
================
*/
qboolean FS_SV_FileExists( const char *file )
{
    FILE *f;
    char *testpath;

    testpath = FS_BuildOSPath( fs_homepath->string, file, "");
    testpath[strlen(testpath)-1] = '\0';

    f = fopen( testpath, "rb" );
    if (f) {
        fclose( f );
        return qtrue;
    }
    return qfalse;
}


/*
===========
FS_SV_FOpenFileWrite

===========
*/
fileHandle_t FS_SV_FOpenFileWrite( const char *filename ) {
    char *ospath;
    fileHandle_t    f;

    if ( !fs_searchpaths ) {
        Com_Error( ERR_FATAL, "Filesystem call made without initialization\n" );
    }

    ospath = FS_BuildOSPath( fs_homepath->string, filename, "" );
    ospath[strlen(ospath)-1] = '\0';

    f = FS_HandleForFile();
    fsh[f].zipFile = qfalse;

    if ( fs_debug->integer ) {
        Com_Printf( "FS_SV_FOpenFileWrite: %s\n", ospath );
    }

    if( FS_CreatePath( ospath ) ) {
        return 0;
    }

    Com_DPrintf( "writing to: %s\n", ospath );
    fsh[f].handleFiles.file.o = fopen( ospath, "wb" );

    Q_strncpyz( fsh[f].name, filename, sizeof( fsh[f].name ) );

    fsh[f].handleSync = qfalse;
    if (!fsh[f].handleFiles.file.o) {
        f = 0;
    }
    return f;
}

/*
===========
FS_SV_FOpenFileRead
search for a file somewhere below the home path, base path or cd path
we search in that order, matching FS_SV_FOpenFileRead order
===========
*/
int FS_SV_FOpenFileRead( const char *filename, fileHandle_t *fp ) {
    char *ospath;
    fileHandle_t    f = 0;

    if ( !fs_searchpaths ) {
        Com_Error( ERR_FATAL, "Filesystem call made without initialization\n" );
    }

    f = FS_HandleForFile();
    fsh[f].zipFile = qfalse;

    Q_strncpyz( fsh[f].name, filename, sizeof( fsh[f].name ) );

    // don't let sound stutter
    S_ClearSoundBuffer();

  // search homepath
    ospath = FS_BuildOSPath( fs_homepath->string, filename, "" );
    // remove trailing slash
    ospath[strlen(ospath)-1] = '\0';

    if ( fs_debug->integer ) {
        Com_Printf( "FS_SV_FOpenFileRead (fs_homepath): %s\n", ospath );
    }

    fsh[f].handleFiles.file.o = fopen( ospath, "rb" );
    fsh[f].handleSync = qfalse;
  if (!fsh[f].handleFiles.file.o)
  {
    // NOTE TTimo on non *nix systems, fs_homepath == fs_basepath, might want to avoid
    if (Q_stricmp(fs_homepath->string,fs_basepath->string))
    {
      // search basepath
      ospath = FS_BuildOSPath( fs_basepath->string, filename, "" );
      ospath[strlen(ospath)-1] = '\0';

      if ( fs_debug->integer )
      {
        Com_Printf( "FS_SV_FOpenFileRead (fs_basepath): %s\n", ospath );
      }

      fsh[f].handleFiles.file.o = fopen( ospath, "rb" );
      fsh[f].handleSync = qfalse;

      if ( !fsh[f].handleFiles.file.o )
      {
        f = 0;
      }
    }
  }

    if (!fsh[f].handleFiles.file.o) {
    // search cd path
    ospath = FS_BuildOSPath( fs_cdpath->string, filename, "" );
    ospath[strlen(ospath)-1] = '\0';

    if (fs_debug->integer)
    {
      Com_Printf( "FS_SV_FOpenFileRead (fs_cdpath) : %s\n", ospath );
    }

      fsh[f].handleFiles.file.o = fopen( ospath, "rb" );
      fsh[f].handleSync = qfalse;

      if( !fsh[f].handleFiles.file.o ) {
        f = 0;
      }
  }
  
    *fp = f;
    if (f) {
        return FS_filelength(f);
    }
    return 0;
}


/*
===========
FS_SV_Rename

===========
*/
void FS_SV_Rename( const char *from, const char *to ) {
    char            *from_ospath, *to_ospath;

    if ( !fs_searchpaths ) {
        Com_Error( ERR_FATAL, "Filesystem call made without initialization\n" );
    }

    // don't let sound stutter
    S_ClearSoundBuffer();

    from_ospath = FS_BuildOSPath( fs_homepath->string, from, "" );
    to_ospath = FS_BuildOSPath( fs_homepath->string, to, "" );
    from_ospath[strlen(from_ospath)-1] = '\0';
    to_ospath[strlen(to_ospath)-1] = '\0';

    if ( fs_debug->integer ) {
        Com_Printf( "FS_SV_Rename: %s --> %s\n", from_ospath, to_ospath );
    }

    if (rename( from_ospath, to_ospath )) {
        // Failed, try copying it and deleting the original
        FS_CopyFile ( from_ospath, to_ospath );
        FS_Remove ( from_ospath );
    }
}



/*
===========
FS_Rename

===========
*/
void FS_Rename( const char *from, const char *to ) {
    char            *from_ospath, *to_ospath;

    if ( !fs_searchpaths ) {
        Com_Error( ERR_FATAL, "Filesystem call made without initialization\n" );
    }

    // don't let sound stutter
    S_ClearSoundBuffer();

    from_ospath = FS_BuildOSPath( fs_homepath->string, fs_gamedir, from );
    to_ospath = FS_BuildOSPath( fs_homepath->string, fs_gamedir, to );

    if ( fs_debug->integer ) {
        Com_Printf( "FS_Rename: %s --> %s\n", from_ospath, to_ospath );
    }

    if (rename( from_ospath, to_ospath )) {
        // Failed, try copying it and deleting the original
        FS_CopyFile ( from_ospath, to_ospath );
        FS_Remove ( from_ospath );
    }
}

/*
==============
FS_FCloseFile

If the FILE pointer is an open pak file, leave it open.

For some reason, other dll's can't just cal fclose()
on files returned by FS_FOpenFile...
==============
*/
void FS_FCloseFile( fileHandle_t f ) {
    if ( !fs_searchpaths ) {
        Com_Error( ERR_FATAL, "Filesystem call made without initialization\n" );
    }

    if (fsh[f].streamed) {
        Sys_EndStreamedFile(f);
    }
    if (fsh[f].zipFile == qtrue) {
        unzCloseCurrentFile( fsh[f].handleFiles.file.z );
        if ( fsh[f].handleFiles.unique ) {
            unzClose( fsh[f].handleFiles.file.z );
        }
        Com_Memset( &fsh[f], 0, sizeof( fsh[f] ) );
        return;
    }

    // we didn't find it as a pak, so close it as a unique file
    if (fsh[f].handleFiles.file.o) {
        fclose (fsh[f].handleFiles.file.o);
    }
    Com_Memset( &fsh[f], 0, sizeof( fsh[f] ) );
}

/*
===========
FS_FOpenFileWrite

===========
*/
fileHandle_t FS_FOpenFileWrite( const char *filename ) {
    char            *ospath;
    fileHandle_t    f;

    if ( !fs_searchpaths ) {
        Com_Error( ERR_FATAL, "Filesystem call made without initialization\n" );
    }

    f = FS_HandleForFile();
    fsh[f].zipFile = qfalse;

    ospath = FS_BuildOSPath( fs_homepath->string, fs_gamedir, filename );

    if ( fs_debug->integer ) {
        Com_Printf( "FS_FOpenFileWrite: %s\n", ospath );
    }

    if( FS_CreatePath( ospath ) ) {
        return 0;
    }

    // enabling the following line causes a recursive function call loop
    // when running with +set logfile 1 +set developer 1
    //Com_DPrintf( "writing to: %s\n", ospath );
    fsh[f].handleFiles.file.o = fopen( ospath, "wb" );

    Q_strncpyz( fsh[f].name, filename, sizeof( fsh[f].name ) );

    fsh[f].handleSync = qfalse;
    if (!fsh[f].handleFiles.file.o) {
        f = 0;
    }
    return f;
}

/*
===========
FS_FOpenFileAppend

===========
*/
fileHandle_t FS_FOpenFileAppend( const char *filename ) {
    char            *ospath;
    fileHandle_t    f;

    if ( !fs_searchpaths ) {
        Com_Error( ERR_FATAL, "Filesystem call made without initialization\n" );
    }

    f = FS_HandleForFile();
    fsh[f].zipFile = qfalse;

    Q_strncpyz( fsh[f].name, filename, sizeof( fsh[f].name ) );

    // don't let sound stutter
    S_ClearSoundBuffer();

    ospath = FS_BuildOSPath( fs_homepath->string, fs_gamedir, filename );

    if ( fs_debug->integer ) {
        Com_Printf( "FS_FOpenFileAppend: %s\n", ospath );
    }

    if( FS_CreatePath( ospath ) ) {
        return 0;
    }

    fsh[f].handleFiles.file.o = fopen( ospath, "ab" );
    fsh[f].handleSync = qfalse;
    if (!fsh[f].handleFiles.file.o) {
        f = 0;
    }
    return f;
}

/*
===========
FS_FilenameCompare

Ignore case and seprator char distinctions
===========
*/
qboolean FS_FilenameCompare( const char *s1, const char *s2 ) {
    int     c1, c2;
    
    do {
        c1 = *s1++;
        c2 = *s2++;

        if (c1 >= 'a' && c1 <= 'z') {
            c1 -= ('a' - 'A');
        }
        if (c2 >= 'a' && c2 <= 'z') {
            c2 -= ('a' - 'A');
        }

        if ( c1 == '\\' || c1 == ':' ) {
            c1 = '/';
        }
        if ( c2 == '\\' || c2 == ':' ) {
            c2 = '/';
        }
        
        if (c1 != c2) {
            return -1;      // strings not equal
        }
    } while (c1);
    
    return 0;       // strings are equal
}

/*
===========
FS_ShiftedStrStr
===========
*/
char *FS_ShiftedStrStr(const char *string, const char *substring, int shift) {
    char buf[MAX_STRING_TOKENS];
    int i;

    for (i = 0; substring[i]; i++) {
        buf[i] = substring[i] + shift;
    }
    buf[i] = '\0';
    return strstr(string, buf);
}

/*
===========
FS_FOpenFileRead

Finds the file in the search path.
Returns filesize and an open FILE pointer.
Used for streaming data out of either a
separate file or a ZIP file.
===========
*/
extern qboolean     com_fullyInitialized;

int FS_FOpenFileRead( const char *filename, fileHandle_t *file, qboolean uniqueFILE ) {
    searchpath_t    *search;
    char            *netpath;
    pack_t          *pak;
    fileInPack_t    *pakFile;
    directory_t     *dir;
    long            hash;
    unz_s           *zfi;
    FILE            *temp;
    int             l;
    char demoExt[16];

    hash = 0;

    if ( !fs_searchpaths ) {
        Com_Error( ERR_FATAL, "Filesystem call made without initialization\n" );
    }

    if ( file == NULL ) {
        // just wants to see if file is there
        for ( search = fs_searchpaths ; search ; search = search->next ) {
            //
            if ( search->pack ) {
                hash = FS_HashFileName(filename, search->pack->hashSize);
            }
            // is the element a pak file?
            if ( search->pack && search->pack->hashTable[hash] ) {
                // look through all the pak file elements
                pak = search->pack;
                pakFile = pak->hashTable[hash];
                do {
                    // case and separator insensitive comparisons
                    if ( !FS_FilenameCompare( pakFile->name, filename ) ) {
                        // found it!
                        return qtrue;
                    }
                    pakFile = pakFile->next;
                } while(pakFile != NULL);
            } else if ( search->dir ) {
                dir = search->dir;
            
                netpath = FS_BuildOSPath( dir->path, dir->gamedir, filename );
                temp = fopen (netpath, "rb");
                if ( !temp ) {
                    continue;
                }
                fclose(temp);
                return qtrue;
            }
        }
        return qfalse;
    }

    if ( !filename ) {
        Com_Error( ERR_FATAL, "FS_FOpenFileRead: NULL 'filename' parameter passed\n" );
    }

    Com_sprintf (demoExt, sizeof(demoExt), ".dm_%d",PROTOCOL_VERSION );
    // qpaths are not supposed to have a leading slash
    if ( filename[0] == '/' || filename[0] == '\\' ) {
        filename++;
    }

    // make absolutely sure that it can't back up the path.
    // The searchpaths do guarantee that something will always
    // be prepended, so we don't need to worry about "c:" or "//limbo" 
    if ( strstr( filename, ".." ) || strstr( filename, "::" ) ) {
        *file = 0;
        return -1;
    }

    // make sure the q3key file is only readable by the quake3.exe at initialization
    // any other time the key should only be accessed in memory using the provided functions
    if( com_fullyInitialized && strstr( filename, "q3key" ) ) {
        *file = 0;
        return -1;
    }

    //
    // search through the path, one element at a time
    //

    *file = FS_HandleForFile();
    fsh[*file].handleFiles.unique = uniqueFILE;

    for ( search = fs_searchpaths ; search ; search = search->next ) {
        //
        if ( search->pack ) {
            hash = FS_HashFileName(filename, search->pack->hashSize);
        }
        // is the element a pak file?
        if ( search->pack && search->pack->hashTable[hash] ) {
            // disregard if it doesn't match one of the allowed pure pak files
            if ( !FS_PakIsPure(search->pack) ) {
                continue;
            }

            // look through all the pak file elements
            pak = search->pack;
            pakFile = pak->hashTable[hash];
            do {
                // case and separator insensitive comparisons
                if ( !FS_FilenameCompare( pakFile->name, filename ) ) {
                    // found it!

                    // mark the pak as having been referenced and mark specifics on cgame and ui
                    // shaders, txt, arena files  by themselves do not count as a reference as 
                    // these are loaded from all pk3s 
                    // from every pk3 file.. 
                    l = strlen( filename );
                    if ( !(pak->referenced & FS_GENERAL_REF)) {
                        if ( Q_stricmp(filename + l - 7, ".shader") != 0 &&
                            Q_stricmp(filename + l - 4, ".txt") != 0 &&
                            Q_stricmp(filename + l - 4, ".cfg") != 0 &&
                            Q_stricmp(filename + l - 7, ".config") != 0 &&
                            strstr(filename, "levelshots") == NULL &&
                            Q_stricmp(filename + l - 4, ".bot") != 0 &&
                            Q_stricmp(filename + l - 6, ".arena") != 0 &&
                            Q_stricmp(filename + l - 5, ".menu") != 0) {
                            pak->referenced |= FS_GENERAL_REF;
                        }
                    }

                    // qagame.qvm   - 13
                    // dTZT`X!di`
                    if (!(pak->referenced & FS_QAGAME_REF) && FS_ShiftedStrStr(filename, "dTZT`X!di`", 13)) {
                        pak->referenced |= FS_QAGAME_REF;
                    }
                    // cgame.qvm    - 7
                    // \`Zf^'jof
                    if (!(pak->referenced & FS_CGAME_REF) && FS_ShiftedStrStr(filename , "\\`Zf^'jof", 7)) {
                        pak->referenced |= FS_CGAME_REF;
                    }
                    // ui.qvm       - 5
                    // pd)lqh
                    if (!(pak->referenced & FS_UI_REF) && FS_ShiftedStrStr(filename , "pd)lqh", 5)) {
                        pak->referenced |= FS_UI_REF;
                    }

                    if ( uniqueFILE ) {
                        // open a new file on the pakfile
                        fsh[*file].handleFiles.file.z = unzReOpen (pak->pakFilename, pak->handle);
                        if (fsh[*file].handleFiles.file.z == NULL) {
                            Com_Error (ERR_FATAL, "Couldn't reopen %s", pak->pakFilename);
                        }
                    } else {
                        fsh[*file].handleFiles.file.z = pak->handle;
                    }
                    Q_strncpyz( fsh[*file].name, filename, sizeof( fsh[*file].name ) );
                    fsh[*file].zipFile = qtrue;
                    zfi = (unz_s *)fsh[*file].handleFiles.file.z;
                    // in case the file was new
                    temp = zfi->file;
                    // set the file position in the zip file (also sets the current file info)
                    unzSetCurrentFileInfoPosition(pak->handle, pakFile->pos);
                    // copy the file info into the unzip structure
                    Com_Memcpy( zfi, pak->handle, sizeof(unz_s) );
                    // we copy this back into the structure
                    zfi->file = temp;
                    // open the file in the zip
                    unzOpenCurrentFile( fsh[*file].handleFiles.file.z );
                    fsh[*file].zipFilePos = pakFile->pos;

                    if ( fs_debug->integer ) {
                        Com_Printf( "FS_FOpenFileRead: %s (found in '%s')\n", 
                            filename, pak->pakFilename );
                    }
                    return zfi->cur_file_info.uncompressed_size;
                }
                pakFile = pakFile->next;
            } while(pakFile != NULL);
        } else if ( search->dir ) {
            // check a file in the directory tree

            // if we are running restricted, the only files we
            // will allow to come from the directory are .cfg files
            l = strlen( filename );
      // FIXME TTimo I'm not sure about the fs_numServerPaks test
      // if you are using FS_ReadFile to find out if a file exists,
      //   this test can make the search fail although the file is in the directory
      // I had the problem on https://zerowing.idsoftware.com/bugzilla/show_bug.cgi?id=8
      // turned out I used FS_FileExists instead
            if ( fs_restrict->integer || fs_numServerPaks ) {

                if ( Q_stricmp( filename + l - 4, ".cfg" )      // for config files
                    && Q_stricmp( filename + l - 5, ".menu" )   // menu files
                    && Q_stricmp( filename + l - 5, ".game" )   // menu files
                    && Q_stricmp( filename + l - strlen(demoExt), demoExt ) // menu files
                    && Q_stricmp( filename + l - 4, ".dat" ) ) {    // for journal files
                    continue;
                }
            }

            dir = search->dir;
            
            netpath = FS_BuildOSPath( dir->path, dir->gamedir, filename );
            fsh[*file].handleFiles.file.o = fopen (netpath, "rb");
            if ( !fsh[*file].handleFiles.file.o ) {
                continue;
            }

            if ( Q_stricmp( filename + l - 4, ".cfg" )      // for config files
                && Q_stricmp( filename + l - 5, ".menu" )   // menu files
                && Q_stricmp( filename + l - 5, ".game" )   // menu files
                && Q_stricmp( filename + l - strlen(demoExt), demoExt ) // menu files
                && Q_stricmp( filename + l - 4, ".dat" ) ) {    // for journal files
                fs_fakeChkSum = random();
            }
      
            Q_strncpyz( fsh[*file].name, filename, sizeof( fsh[*file].name ) );
            fsh[*file].zipFile = qfalse;
            if ( fs_debug->integer ) {
                Com_Printf( "FS_FOpenFileRead: %s (found in '%s/%s')\n", filename,
                    dir->path, dir->gamedir );
            }

            // if we are getting it from the cdpath, optionally copy it
            //  to the basepath
            if ( fs_copyfiles->integer && !Q_stricmp( dir->path, fs_cdpath->string ) ) {
                char    *copypath;

                copypath = FS_BuildOSPath( fs_basepath->string, dir->gamedir, filename );
                FS_CopyFile( netpath, copypath );
            }

            return FS_filelength (*file);
        }       
    }
    
    Com_DPrintf ("Can't find %s\n", filename);
#ifdef FS_MISSING
    if (missingFiles) {
        fprintf(missingFiles, "%s\n", filename);
    }
#endif
    *file = 0;
    return -1;
}


/*
=================
FS_Read

Properly handles partial reads
=================
*/
int FS_Read2( void *buffer, int len, fileHandle_t f ) {
    if ( !fs_searchpaths ) {
        Com_Error( ERR_FATAL, "Filesystem call made without initialization\n" );
    }

    if ( !f ) {
        return 0;
    }
    if (fsh[f].streamed) {
        int r;
        fsh[f].streamed = qfalse;
        r = Sys_StreamedRead( buffer, len, 1, f);
        fsh[f].streamed = qtrue;
        return r;
    } else {
        return FS_Read( buffer, len, f);
    }
}

int FS_Read( void *buffer, int len, fileHandle_t f ) {
    int     block, remaining;
    int     read;
    byte    *buf;
    int     tries;

    if ( !fs_searchpaths ) {
        Com_Error( ERR_FATAL, "Filesystem call made without initialization\n" );
    }

    if ( !f ) {
        return 0;
    }

    buf = (byte *)buffer;
    fs_readCount += len;

    if (fsh[f].zipFile == qfalse) {
        remaining = len;
        tries = 0;
        while (remaining) {
            block = remaining;
            read = fread (buf, 1, block, fsh[f].handleFiles.file.o);
            if (read == 0) {
                // we might have been trying to read from a CD, which
                // sometimes returns a 0 read on windows
                if (!tries) {
                    tries = 1;
                } else {
                    return len-remaining;   //Com_Error (ERR_FATAL, "FS_Read: 0 bytes read");
                }
            }

            if (read == -1) {
                Com_Error (ERR_FATAL, "FS_Read: -1 bytes read");
            }

            remaining -= read;
            buf += read;
        }
        return len;
    } else {
        return unzReadCurrentFile(fsh[f].handleFiles.file.z, buffer, len);
    }
}

/*
=================
FS_Write

Properly handles partial writes
=================
*/
int FS_Write( const void *buffer, int len, fileHandle_t h ) {
    int     block, remaining;
    int     written;
    byte    *buf;
    int     tries;
    FILE    *f;

    if ( !fs_searchpaths ) {
        Com_Error( ERR_FATAL, "Filesystem call made without initialization\n" );
    }

    if ( !h ) {
        return 0;
    }

    f = FS_FileForHandle(h);
    buf = (byte *)buffer;

    remaining = len;
    tries = 0;
    while (remaining) {
        block = remaining;
        written = fwrite (buf, 1, block, f);
        if (written == 0) {
            if (!tries) {
                tries = 1;
            } else {
                Com_Printf( "FS_Write: 0 bytes written\n" );
                return 0;
            }
        }

        if (written == -1) {
            Com_Printf( "FS_Write: -1 bytes written\n" );
            return 0;
        }

        remaining -= written;
        buf += written;
    }
    if ( fsh[h].handleSync ) {
        fflush( f );
    }
    return len;
}

void QDECL FS_Printf( fileHandle_t h, const char *fmt, ... ) {
    va_list     argptr;
    char        msg[MAXPRINTMSG];

    va_start (argptr,fmt);
    Q_vsnprintf (msg, sizeof(msg), fmt, argptr);
    va_end (argptr);

    FS_Write(msg, strlen(msg), h);
}

/*
=================
FS_Seek

=================
*/
int FS_Seek( fileHandle_t f, long offset, int origin ) {
    int     _origin;
    char    foo[65536];

    if ( !fs_searchpaths ) {
        Com_Error( ERR_FATAL, "Filesystem call made without initialization\n" );
        return -1;
    }

    if (fsh[f].streamed) {
        fsh[f].streamed = qfalse;
        Sys_StreamSeek( f, offset, origin );
        fsh[f].streamed = qtrue;
    }

    if (fsh[f].zipFile == qtrue) {
        if (offset == 0 && origin == FS_SEEK_SET) {
            // set the file position in the zip file (also sets the current file info)
            unzSetCurrentFileInfoPosition(fsh[f].handleFiles.file.z, fsh[f].zipFilePos);
            return unzOpenCurrentFile(fsh[f].handleFiles.file.z);
        } else if (offset<65536) {
            // set the file position in the zip file (also sets the current file info)
            unzSetCurrentFileInfoPosition(fsh[f].handleFiles.file.z, fsh[f].zipFilePos);
            unzOpenCurrentFile(fsh[f].handleFiles.file.z);
            return FS_Read(foo, offset, f);
        } else {
            Com_Error( ERR_FATAL, "ZIP FILE FSEEK NOT YET IMPLEMENTED\n" );
            return -1;
        }
    } else {
        FILE *file;
        file = FS_FileForHandle(f);
        switch( origin ) {
        case FS_SEEK_CUR:
            _origin = SEEK_CUR;
            break;
        case FS_SEEK_END:
            _origin = SEEK_END;
            break;
        case FS_SEEK_SET:
            _origin = SEEK_SET;
            break;
        default:
            _origin = SEEK_CUR;
            Com_Error( ERR_FATAL, "Bad origin in FS_Seek\n" );
            break;
        }

        return fseek( file, offset, _origin );
    }
}


/*
======================================================================================

CONVENIENCE FUNCTIONS FOR ENTIRE FILES

======================================================================================
*/

int FS_FileIsInPAK(const char *filename, int *pChecksum ) {
    searchpath_t    *search;
    pack_t          *pak;
    fileInPack_t    *pakFile;
    long            hash = 0;

    if ( !fs_searchpaths ) {
        Com_Error( ERR_FATAL, "Filesystem call made without initialization\n" );
    }

    if ( !filename ) {
        Com_Error( ERR_FATAL, "FS_FOpenFileRead: NULL 'filename' parameter passed\n" );
    }

    // qpaths are not supposed to have a leading slash
    if ( filename[0] == '/' || filename[0] == '\\' ) {
        filename++;
    }

    // make absolutely sure that it can't back up the path.
    // The searchpaths do guarantee that something will always
    // be prepended, so we don't need to worry about "c:" or "//limbo" 
    if ( strstr( filename, ".." ) || strstr( filename, "::" ) ) {
        return -1;
    }

    //
    // search through the path, one element at a time
    //

    for ( search = fs_searchpaths ; search ; search = search->next ) {
        //
        if (search->pack) {
            hash = FS_HashFileName(filename, search->pack->hashSize);
        }
        // is the element a pak file?
        if ( search->pack && search->pack->hashTable[hash] ) {
            // disregard if it doesn't match one of the allowed pure pak files
            if ( !FS_PakIsPure(search->pack) ) {
                continue;
            }

            // look through all the pak file elements
            pak = search->pack;
            pakFile = pak->hashTable[hash];
            do {
                // case and separator insensitive comparisons
                if ( !FS_FilenameCompare( pakFile->name, filename ) ) {
                    if (pChecksum) {
                        *pChecksum = pak->pure_checksum;
                    }
                    return 1;
                }
                pakFile = pakFile->next;
            } while(pakFile != NULL);
        }
    }
    return -1;
}

/*
============
FS_ReadFile

Filename are relative to the quake search path
a null buffer will just return the file length without loading
============
*/
int FS_ReadFile( const char *qpath, void **buffer ) {
    fileHandle_t    h;
    byte*           buf;
    qboolean        isConfig;
    int             len;

    if ( !fs_searchpaths ) {
        Com_Error( ERR_FATAL, "Filesystem call made without initialization\n" );
    }

    if ( !qpath || !qpath[0] ) {
        Com_Error( ERR_FATAL, "FS_ReadFile with empty name\n" );
    }

    buf = NULL; // quiet compiler warning

    // if this is a .cfg file and we are playing back a journal, read
    // it from the journal file
    if ( strstr( qpath, ".cfg" ) ) {
        isConfig = qtrue;
        if ( com_journal && com_journal->integer == 2 ) {
            int     r;

            Com_DPrintf( "Loading %s from journal file.\n", qpath );
            r = FS_Read( &len, sizeof( len ), com_journalDataFile );
            if ( r != sizeof( len ) ) {
                if (buffer != NULL) *buffer = NULL;
                return -1;
            }
            // if the file didn't exist when the journal was created
            if (!len) {
                if (buffer == NULL) {
                    return 1;           // hack for old journal files
                }
                *buffer = NULL;
                return -1;
            }
            if (buffer == NULL) {
                return len;
            }

            buf = Hunk_AllocateTempMemory(len+1);
            *buffer = buf;

            r = FS_Read( buf, len, com_journalDataFile );
            if ( r != len ) {
                Com_Error( ERR_FATAL, "Read from journalDataFile failed" );
            }

            fs_loadCount++;
            fs_loadStack++;

            // guarantee that it will have a trailing 0 for string operations
            buf[len] = 0;

            return len;
        }
    } else {
        isConfig = qfalse;
    }

    // look for it in the filesystem or pack files
    len = FS_FOpenFileRead( qpath, &h, qfalse );
    if ( h == 0 ) {
        if ( buffer ) {
            *buffer = NULL;
        }
        // if we are journalling and it is a config file, write a zero to the journal file
        if ( isConfig && com_journal && com_journal->integer == 1 ) {
            Com_DPrintf( "Writing zero for %s to journal file.\n", qpath );
            len = 0;
            FS_Write( &len, sizeof( len ), com_journalDataFile );
            FS_Flush( com_journalDataFile );
        }
        return -1;
    }
    
    if ( !buffer ) {
        if ( isConfig && com_journal && com_journal->integer == 1 ) {
            Com_DPrintf( "Writing len for %s to journal file.\n", qpath );
            FS_Write( &len, sizeof( len ), com_journalDataFile );
            FS_Flush( com_journalDataFile );
        }
        FS_FCloseFile( h);
        return len;
    }

    fs_loadCount++;
    fs_loadStack++;

    buf = Hunk_AllocateTempMemory(len+1);
    *buffer = buf;

    FS_Read (buf, len, h);

    // guarantee that it will have a trailing 0 for string operations
    buf[len] = 0;
    FS_FCloseFile( h );

    // if we are journalling and it is a config file, write it to the journal file
    if ( isConfig && com_journal && com_journal->integer == 1 ) {
        Com_DPrintf( "Writing %s to journal file.\n", qpath );
        FS_Write( &len, sizeof( len ), com_journalDataFile );
        FS_Write( buf, len, com_journalDataFile );
        FS_Flush( com_journalDataFile );
    }
    return len;
}

/*
=============
FS_FreeFile
=============
*/
void FS_FreeFile( void *buffer ) {
    if ( !fs_searchpaths ) {
        Com_Error( ERR_FATAL, "Filesystem call made without initialization\n" );
    }
    if ( !buffer ) {
        Com_Error( ERR_FATAL, "FS_FreeFile( NULL )" );
    }
    fs_loadStack--;

    Hunk_FreeTempMemory( buffer );

    // if all of our temp files are free, clear all of our space
    if ( fs_loadStack == 0 ) {
        Hunk_ClearTempMemory();
    }
}

/*
============
FS_WriteFile

Filename are reletive to the quake search path
============
*/
void FS_WriteFile( const char *qpath, const void *buffer, int size ) {
    fileHandle_t f;

    if ( !fs_searchpaths ) {
        Com_Error( ERR_FATAL, "Filesystem call made without initialization\n" );
    }

    if ( !qpath || !buffer ) {
        Com_Error( ERR_FATAL, "FS_WriteFile: NULL parameter" );
    }

    f = FS_FOpenFileWrite( qpath );
    if ( !f ) {
        Com_Printf( "Failed to open %s\n", qpath );
        return;
    }

    FS_Write( buffer, size, f );

    FS_FCloseFile( f );
}



/*
==========================================================================

ZIP FILE LOADING

==========================================================================
*/

/*
=================
FS_LoadZipFile

Creates a new pak_t in the search chain for the contents
of a zip file.
=================
*/
static pack_t *FS_LoadZipFile( char *zipfile, const char *basename )
{
    fileInPack_t    *buildBuffer;
    pack_t          *pack;
    unzFile         uf;
    int             err;
    unz_global_info gi;
    char            filename_inzip[MAX_ZPATH];
    unz_file_info   file_info;
    int             i, len;
    long            hash;
    int             fs_numHeaderLongs;
    int             *fs_headerLongs;
    char            *namePtr;

    fs_numHeaderLongs = 0;

    uf = unzOpen(zipfile);
    err = unzGetGlobalInfo (uf,&gi);

    if (err != UNZ_OK)
        return NULL;

    fs_packFiles += gi.number_entry;

    len = 0;
    unzGoToFirstFile(uf);
    for (i = 0; i < gi.number_entry; i++)
    {
        err = unzGetCurrentFileInfo(uf, &file_info, filename_inzip, sizeof(filename_inzip), NULL, 0, NULL, 0);
        if (err != UNZ_OK) {
            break;
        }
        len += strlen(filename_inzip) + 1;
        unzGoToNextFile(uf);
    }

    buildBuffer = Z_Malloc( (gi.number_entry * sizeof( fileInPack_t )) + len );
    namePtr = ((char *) buildBuffer) + gi.number_entry * sizeof( fileInPack_t );
    fs_headerLongs = Z_Malloc( gi.number_entry * sizeof(int) );

    // get the hash table size from the number of files in the zip
    // because lots of custom pk3 files have less than 32 or 64 files
    for (i = 1; i <= MAX_FILEHASH_SIZE; i <<= 1) {
        if (i > gi.number_entry) {
            break;
        }
    }

    pack = Z_Malloc( sizeof( pack_t ) + i * sizeof(fileInPack_t *) );
    pack->hashSize = i;
    pack->hashTable = (fileInPack_t **) (((char *) pack) + sizeof( pack_t ));
    for(i = 0; i < pack->hashSize; i++) {
        pack->hashTable[i] = NULL;
    }

    Q_strncpyz( pack->pakFilename, zipfile, sizeof( pack->pakFilename ) );
    Q_strncpyz( pack->pakBasename, basename, sizeof( pack->pakBasename ) );

    // strip .pk3 if needed
    if ( strlen( pack->pakBasename ) > 4 && !Q_stricmp( pack->pakBasename + strlen( pack->pakBasename ) - 4, ".pk3" ) ) {
        pack->pakBasename[strlen( pack->pakBasename ) - 4] = 0;
    }

    pack->handle = uf;
    pack->numfiles = gi.number_entry;
    unzGoToFirstFile(uf);

    for (i = 0; i < gi.number_entry; i++)
    {
        err = unzGetCurrentFileInfo(uf, &file_info, filename_inzip, sizeof(filename_inzip), NULL, 0, NULL, 0);
        if (err != UNZ_OK) {
            break;
        }
        if (file_info.uncompressed_size > 0) {
            fs_headerLongs[fs_numHeaderLongs++] = LittleLong(file_info.crc);
        }
        Q_strlwr( filename_inzip );
        hash = FS_HashFileName(filename_inzip, pack->hashSize);
        buildBuffer[i].name = namePtr;
        strcpy( buildBuffer[i].name, filename_inzip );
        namePtr += strlen(filename_inzip) + 1;
        // store the file position in the zip
        unzGetCurrentFileInfoPosition(uf, &buildBuffer[i].pos);
        //
        buildBuffer[i].next = pack->hashTable[hash];
        pack->hashTable[hash] = &buildBuffer[i];
        unzGoToNextFile(uf);
    }

    pack->checksum = Com_BlockChecksum( fs_headerLongs, 4 * fs_numHeaderLongs );
    pack->pure_checksum = Com_BlockChecksumKey( fs_headerLongs, 4 * fs_numHeaderLongs, LittleLong(fs_checksumFeed) );
    pack->checksum = LittleLong( pack->checksum );
    pack->pure_checksum = LittleLong( pack->pure_checksum );

    Z_Free(fs_headerLongs);

    pack->buildBuffer = buildBuffer;
    return pack;
}

/*
=================================================================================

DIRECTORY SCANNING FUNCTIONS

=================================================================================
*/

#define MAX_FOUND_FILES 0x1000

static int FS_ReturnPath( const char *zname, char *zpath, int *depth ) {
    int len, at, newdep;

    newdep = 0;
    zpath[0] = 0;
    len = 0;
    at = 0;

    while(zname[at] != 0)
    {
        if (zname[at]=='/' || zname[at]=='\\') {
            len = at;
            newdep++;
        }
        at++;
    }
    strcpy(zpath, zname);
    zpath[len] = 0;
    *depth = newdep;

    return len;
}

/*
==================
FS_AddFileToList
==================
*/
static int FS_AddFileToList( char *name, char *list[MAX_FOUND_FILES], int nfiles ) {
    int     i;

    if ( nfiles == MAX_FOUND_FILES - 1 ) {
        return nfiles;
    }
    for ( i = 0 ; i < nfiles ; i++ ) {
        if ( !Q_stricmp( name, list[i] ) ) {
            return nfiles;      // allready in list
        }
    }
    list[nfiles] = CopyString( name );
    nfiles++;

    return nfiles;
}

/*
===============
FS_ListFilteredFiles

Returns a uniqued list of files that match the given criteria
from all search paths
===============
*/
char **FS_ListFilteredFiles( const char *path, const char *extension, char *filter, int *numfiles ) {
    int             nfiles;
    char            **listCopy;
    char            *list[MAX_FOUND_FILES];
    searchpath_t    *search;
    int             i;
    int             pathLength;
    int             extensionLength;
    int             length, pathDepth, temp;
    pack_t          *pak;
    fileInPack_t    *buildBuffer;
    char            zpath[MAX_ZPATH];

    if ( !fs_searchpaths ) {
        Com_Error( ERR_FATAL, "Filesystem call made without initialization\n" );
    }

    if ( !path ) {
        *numfiles = 0;
        return NULL;
    }
    if ( !extension ) {
        extension = "";
    }

    pathLength = strlen( path );
    if ( path[pathLength-1] == '\\' || path[pathLength-1] == '/' ) {
        pathLength--;
    }
    extensionLength = strlen( extension );
    nfiles = 0;
    FS_ReturnPath(path, zpath, &pathDepth);

    //
    // search through the path, one element at a time, adding to list
    //
    for (search = fs_searchpaths ; search ; search = search->next) {
        // is the element a pak file?
        if (search->pack) {

            //ZOID:  If we are pure, don't search for files on paks that
            // aren't on the pure list
            if ( !FS_PakIsPure(search->pack) ) {
                continue;
            }

            // look through all the pak file elements
            pak = search->pack;
            buildBuffer = pak->buildBuffer;
            for (i = 0; i < pak->numfiles; i++) {
                char    *name;
                int     zpathLen, depth;

                // check for directory match
                name = buildBuffer[i].name;
                //
                if (filter) {
                    // case insensitive
                    if (!Com_FilterPath( filter, name, qfalse ))
                        continue;
                    // unique the match
                    nfiles = FS_AddFileToList( name, list, nfiles );
                }
                else {

                    zpathLen = FS_ReturnPath(name, zpath, &depth);

                    if ( (depth-pathDepth)>2 || pathLength > zpathLen || Q_stricmpn( name, path, pathLength ) ) {
                        continue;
                    }

                    // check for extension match
                    length = strlen( name );
                    if ( length < extensionLength ) {
                        continue;
                    }

                    if ( Q_stricmp( name + length - extensionLength, extension ) ) {
                        continue;
                    }
                    // unique the match

                    temp = pathLength;
                    if (pathLength) {
                        temp++;     // include the '/'
                    }
                    nfiles = FS_AddFileToList( name + temp, list, nfiles );
                }
            }
        } else if (search->dir) { // scan for files in the filesystem
            char    *netpath;
            int     numSysFiles;
            char    **sysFiles;
            char    *name;

            // don't scan directories for files if we are pure or restricted
            if ( fs_restrict->integer || fs_numServerPaks ) {
                continue;
            } else {
                netpath = FS_BuildOSPath( search->dir->path, search->dir->gamedir, path );
                sysFiles = Sys_ListFiles( netpath, extension, filter, &numSysFiles, qfalse );
                for ( i = 0 ; i < numSysFiles ; i++ ) {
                    // unique the match
                    name = sysFiles[i];
                    nfiles = FS_AddFileToList( name, list, nfiles );
                }
                Sys_FreeFileList( sysFiles );
            }
        }       
    }

    // return a copy of the list
    *numfiles = nfiles;

    if ( !nfiles ) {
        return NULL;
    }

    listCopy = Z_Malloc( ( nfiles + 1 ) * sizeof( *listCopy ) );
    for ( i = 0 ; i < nfiles ; i++ ) {
        listCopy[i] = list[i];
    }
    listCopy[i] = NULL;

    return listCopy;
}

/*
=================
FS_ListFiles
=================
*/
char **FS_ListFiles( const char *path, const char *extension, int *numfiles ) {
    return FS_ListFilteredFiles( path, extension, NULL, numfiles );
}

/*
=================
FS_FreeFileList
=================
*/
void FS_FreeFileList( char **list ) {
    int     i;

    if ( !fs_searchpaths ) {
        Com_Error( ERR_FATAL, "Filesystem call made without initialization\n" );
    }

    if ( !list ) {
        return;
    }

    for ( i = 0 ; list[i] ; i++ ) {
        Z_Free( list[i] );
    }

    Z_Free( list );
}


/*
================
FS_GetFileList
================
*/
int FS_GetFileList(  const char *path, const char *extension, char *listbuf, int bufsize ) {
    int     nFiles, i, nTotal, nLen;
    char **pFiles = NULL;

    *listbuf = 0;
    nFiles = 0;
    nTotal = 0;

    if (Q_stricmp(path, "$modlist") == 0) {
        return FS_GetModList(listbuf, bufsize);
    }

    pFiles = FS_ListFiles(path, extension, &nFiles);

    for (i =0; i < nFiles; i++) {
        nLen = strlen(pFiles[i]) + 1;
        if (nTotal + nLen + 1 < bufsize) {
            strcpy(listbuf, pFiles[i]);
            listbuf += nLen;
            nTotal += nLen;
        }
        else {
            nFiles = i;
            break;
        }
    }

    FS_FreeFileList(pFiles);

    return nFiles;
}

/*
=======================
Sys_ConcatenateFileLists

mkv: Naive implementation. Concatenates three lists into a
     new list, and frees the old lists from the heap.
bk001129 - from cvs1.17 (mkv)

FIXME TTimo those two should move to common.c next to Sys_ListFiles
=======================
 */
static unsigned int Sys_CountFileList(char **list)
{
  int i = 0;

  if (list)
  {
    while (*list)
    {
      list++;
      i++;
    }
  }
  return i;
}

static char** Sys_ConcatenateFileLists( char **list0, char **list1, char **list2 )
{
  int totalLength = 0;
  char** cat = NULL, **dst, **src;

  totalLength += Sys_CountFileList(list0);
  totalLength += Sys_CountFileList(list1);
  totalLength += Sys_CountFileList(list2);

  /* Create new list. */
  dst = cat = Z_Malloc( ( totalLength + 1 ) * sizeof( char* ) );

  /* Copy over lists. */
  if (list0)
  {
    for (src = list0; *src; src++, dst++)
      *dst = *src;
  }
  if (list1)
  {
    for (src = list1; *src; src++, dst++)
      *dst = *src;
  }
  if (list2)
  {
    for (src = list2; *src; src++, dst++)
      *dst = *src;
  }

  // Terminate the list
  *dst = NULL;

  // Free our old lists.
  // NOTE: not freeing their content, it's been merged in dst and still being used
  if (list0) Z_Free( list0 );
  if (list1) Z_Free( list1 );
  if (list2) Z_Free( list2 );

  return cat;
}

/*
================
FS_GetModList

Returns a list of mod directory names
A mod directory is a peer to baseq3 with a pk3 in it
The directories are searched in base path, cd path and home path
================
*/
int FS_GetModList( char *listbuf, int bufsize ) {
  int       nMods, i, j, nTotal, nLen, nPaks, nPotential, nDescLen;
  char **pFiles = NULL;
  char **pPaks = NULL;
  char *name, *path;
  char descPath[MAX_OSPATH];
  fileHandle_t descHandle;

  int dummy;
  char **pFiles0 = NULL;
  char **pFiles1 = NULL;
  char **pFiles2 = NULL;
  qboolean bDrop = qfalse;

  *listbuf = 0;
  nMods = nPotential = nTotal = 0;

  pFiles0 = Sys_ListFiles( fs_homepath->string, NULL, NULL, &dummy, qtrue );
  pFiles1 = Sys_ListFiles( fs_basepath->string, NULL, NULL, &dummy, qtrue );
  pFiles2 = Sys_ListFiles( fs_cdpath->string, NULL, NULL, &dummy, qtrue );
  // we searched for mods in the three paths
  // it is likely that we have duplicate names now, which we will cleanup below
  pFiles = Sys_ConcatenateFileLists( pFiles0, pFiles1, pFiles2 );
  nPotential = Sys_CountFileList(pFiles);

  for ( i = 0 ; i < nPotential ; i++ ) {
    name = pFiles[i];
    // NOTE: cleaner would involve more changes
    // ignore duplicate mod directories
    if (i!=0) {
      bDrop = qfalse;
      for(j=0; j<i; j++)
      {
        if (Q_stricmp(pFiles[j],name)==0) {
          // this one can be dropped
          bDrop = qtrue;
          break;
        }
      }
    }
    if (bDrop) {
      continue;
    }
    // we drop "baseq3" "." and ".."
    if (Q_stricmp(name, "baseq3") && Q_stricmpn(name, ".", 1)) {
      // now we need to find some .pk3 files to validate the mod
      // NOTE TTimo: (actually I'm not sure why .. what if it's a mod under developement with no .pk3?)
      // we didn't keep the information when we merged the directory names, as to what OS Path it was found under
      //   so it could be in base path, cd path or home path
      //   we will try each three of them here (yes, it's a bit messy)
      path = FS_BuildOSPath( fs_basepath->string, name, "" );
      nPaks = 0;
      pPaks = Sys_ListFiles(path, ".pk3", NULL, &nPaks, qfalse); 
      Sys_FreeFileList( pPaks ); // we only use Sys_ListFiles to check wether .pk3 files are present

      /* Try on cd path */
      if( nPaks <= 0 ) {
        path = FS_BuildOSPath( fs_cdpath->string, name, "" );
        nPaks = 0;
        pPaks = Sys_ListFiles( path, ".pk3", NULL, &nPaks, qfalse );
        Sys_FreeFileList( pPaks );
      }

      /* try on home path */
      if ( nPaks <= 0 )
      {
        path = FS_BuildOSPath( fs_homepath->string, name, "" );
        nPaks = 0;
        pPaks = Sys_ListFiles( path, ".pk3", NULL, &nPaks, qfalse );
        Sys_FreeFileList( pPaks );
      }

      if (nPaks > 0) {
        nLen = strlen(name) + 1;
        // nLen is the length of the mod path
        // we need to see if there is a description available
        descPath[0] = '\0';
        strcpy(descPath, name);
        strcat(descPath, "/description.txt");
        nDescLen = FS_SV_FOpenFileRead( descPath, &descHandle );
        if ( nDescLen > 0 && descHandle) {
          FILE *file;
          file = FS_FileForHandle(descHandle);
          Com_Memset( descPath, 0, sizeof( descPath ) );
          nDescLen = fread(descPath, 1, 48, file);
          if (nDescLen >= 0) {
            descPath[nDescLen] = '\0';
          }
          FS_FCloseFile(descHandle);
        } else {
          strcpy(descPath, name);
        }
        nDescLen = strlen(descPath) + 1;

        if (nTotal + nLen + 1 + nDescLen + 1 < bufsize) {
          strcpy(listbuf, name);
          listbuf += nLen;
          strcpy(listbuf, descPath);
          listbuf += nDescLen;
          nTotal += nLen + nDescLen;
          nMods++;
        }
        else {
          break;
        }
      }
    }
  }
  Sys_FreeFileList( pFiles );

  return nMods;
}




//============================================================================

/*
================
FS_Dir_f
================
*/
void FS_Dir_f( void ) {
    char    *path;
    char    *extension;
    char    **dirnames;
    int     ndirs;
    int     i;

    if ( Cmd_Argc() < 2 || Cmd_Argc() > 3 ) {
        Com_Printf( "usage: dir <directory> [extension]\n" );
        return;
    }

    if ( Cmd_Argc() == 2 ) {
        path = Cmd_Argv( 1 );
        extension = "";
    } else {
        path = Cmd_Argv( 1 );
        extension = Cmd_Argv( 2 );
    }

    Com_Printf( "Directory of %s %s\n", path, extension );
    Com_Printf( "---------------\n" );

    dirnames = FS_ListFiles( path, extension, &ndirs );

    for ( i = 0; i < ndirs; i++ ) {
        Com_Printf( "%s\n", dirnames[i] );
    }
    FS_FreeFileList( dirnames );
}

/*
===========
FS_ConvertPath
===========
*/
void FS_ConvertPath( char *s ) {
    while (*s) {
        if ( *s == '\\' || *s == ':' ) {
            *s = '/';
        }
        s++;
    }
}

/*
===========
FS_PathCmp

Ignore case and seprator char distinctions
===========
*/
int FS_PathCmp( const char *s1, const char *s2 ) {
    int     c1, c2;
    
    do {
        c1 = *s1++;
        c2 = *s2++;

        if (c1 >= 'a' && c1 <= 'z') {
            c1 -= ('a' - 'A');
        }
        if (c2 >= 'a' && c2 <= 'z') {
            c2 -= ('a' - 'A');
        }

        if ( c1 == '\\' || c1 == ':' ) {
            c1 = '/';
        }
        if ( c2 == '\\' || c2 == ':' ) {
            c2 = '/';
        }
        
        if (c1 < c2) {
            return -1;      // strings not equal
        }
        if (c1 > c2) {
            return 1;
        }
    } while (c1);
    
    return 0;       // strings are equal
}

/*
================
FS_SortFileList
================
*/
void FS_SortFileList(char **filelist, int numfiles) {
    int i, j, k, numsortedfiles;
    char **sortedlist;

    sortedlist = Z_Malloc( ( numfiles + 1 ) * sizeof( *sortedlist ) );
    sortedlist[0] = NULL;
    numsortedfiles = 0;
    for (i = 0; i < numfiles; i++) {
        for (j = 0; j < numsortedfiles; j++) {
            if (FS_PathCmp(filelist[i], sortedlist[j]) < 0) {
                break;
            }
        }
        for (k = numsortedfiles; k > j; k--) {
            sortedlist[k] = sortedlist[k-1];
        }
        sortedlist[j] = filelist[i];
        numsortedfiles++;
    }
    Com_Memcpy(filelist, sortedlist, numfiles * sizeof( *filelist ) );
    Z_Free(sortedlist);
}

/*
================
FS_NewDir_f
================
*/
void FS_NewDir_f( void ) {
    char    *filter;
    char    **dirnames;
    int     ndirs;
    int     i;

    if ( Cmd_Argc() < 2 ) {
        Com_Printf( "usage: fdir <filter>\n" );
        Com_Printf( "example: fdir *q3dm*.bsp\n");
        return;
    }

    filter = Cmd_Argv( 1 );

    Com_Printf( "---------------\n" );

    dirnames = FS_ListFilteredFiles( "", "", filter, &ndirs );

    FS_SortFileList(dirnames, ndirs);

    for ( i = 0; i < ndirs; i++ ) {
        FS_ConvertPath(dirnames[i]);
        Com_Printf( "%s\n", dirnames[i] );
    }
    Com_Printf( "%d files listed\n", ndirs );
    FS_FreeFileList( dirnames );
}

/*
============
FS_Path_f

============
*/
void FS_Path_f( void ) {
    searchpath_t    *s;
    int             i;

    Com_Printf ("Current search path:\n");
    for (s = fs_searchpaths; s; s = s->next) {
        if (s->pack) {
            Com_Printf ("%s (%i files)\n", s->pack->pakFilename, s->pack->numfiles);
            if ( fs_numServerPaks ) {
                if ( !FS_PakIsPure(s->pack) ) {
                    Com_Printf( "    not on the pure list\n" );
                } else {
                    Com_Printf( "    on the pure list\n" );
                }
            }
        } else {
            Com_Printf ("%s/%s\n", s->dir->path, s->dir->gamedir );
        }
    }


    Com_Printf( "\n" );
    for ( i = 1 ; i < MAX_FILE_HANDLES ; i++ ) {
        if ( fsh[i].handleFiles.file.o ) {
            Com_Printf( "handle %i: %s\n", i, fsh[i].name );
        }
    }
}

/*
============
FS_TouchFile_f

The only purpose of this function is to allow game script files to copy
arbitrary files furing an "fs_copyfiles 1" run.
============
*/
void FS_TouchFile_f( void ) {
    fileHandle_t    f;

    if ( Cmd_Argc() != 2 ) {
        Com_Printf( "Usage: touchFile <file>\n" );
        return;
    }

    FS_FOpenFileRead( Cmd_Argv( 1 ), &f, qfalse );
    if ( f ) {
        FS_FCloseFile( f );
    }
}

//===========================================================================


static int QDECL paksort( const void *a, const void *b ) {
    char    *aa, *bb;

    aa = *(char **)a;
    bb = *(char **)b;

    return FS_PathCmp( aa, bb );
}

/*
================
FS_AddGameDirectory

Sets fs_gamedir, adds the directory to the head of the path,
then loads the zip headers
================
*/
#define MAX_PAKFILES    1024
static void FS_AddGameDirectory( const char *path, const char *dir ) {
    searchpath_t    *sp;
    int             i;
    searchpath_t    *search;
    pack_t          *pak;
    char            *pakfile;
    int             numfiles;
    char            **pakfiles;
    char            *sorted[MAX_PAKFILES];

    // this fixes the case where fs_basepath is the same as fs_cdpath
    // which happens on full installs
    for ( sp = fs_searchpaths ; sp ; sp = sp->next ) {
        if ( sp->dir && !Q_stricmp(sp->dir->path, path) && !Q_stricmp(sp->dir->gamedir, dir)) {
            return;         // we've already got this one
        }
    }
    
    Q_strncpyz( fs_gamedir, dir, sizeof( fs_gamedir ) );

    //
    // add the directory to the search path
    //
    search = Z_Malloc (sizeof(searchpath_t));
    search->dir = Z_Malloc( sizeof( *search->dir ) );

    Q_strncpyz( search->dir->path, path, sizeof( search->dir->path ) );
    Q_strncpyz( search->dir->gamedir, dir, sizeof( search->dir->gamedir ) );
    search->next = fs_searchpaths;
    fs_searchpaths = search;

    // find all pak files in this directory
    pakfile = FS_BuildOSPath( path, dir, "" );
    pakfile[ strlen(pakfile) - 1 ] = 0; // strip the trailing slash

    pakfiles = Sys_ListFiles( pakfile, ".pk3", NULL, &numfiles, qfalse );

    // sort them so that later alphabetic matches override
    // earlier ones.  This makes pak1.pk3 override pak0.pk3
    if ( numfiles > MAX_PAKFILES ) {
        numfiles = MAX_PAKFILES;
    }
    for ( i = 0 ; i < numfiles ; i++ ) {
        sorted[i] = pakfiles[i];
    }

    qsort( sorted, numfiles, 4, paksort );

    for ( i = 0 ; i < numfiles ; i++ ) {
        pakfile = FS_BuildOSPath( path, dir, sorted[i] );
        if ( ( pak = FS_LoadZipFile( pakfile, sorted[i] ) ) == 0 )
            continue;
        // store the game name for downloading
        strcpy(pak->pakGamename, dir);

        search = Z_Malloc (sizeof(searchpath_t));
        search->pack = pak;
        search->next = fs_searchpaths;
        fs_searchpaths = search;
    }

    // done
    Sys_FreeFileList( pakfiles );
}

/*
================
FS_idPak
================
*/
qboolean FS_idPak( char *pak, char *base ) {
    int i;

    for (i = 0; i < NUM_ID_PAKS; i++) {
        if ( !FS_FilenameCompare(pak, va("%s/pak%d", base, i)) ) {
            break;
        }
    }
    if (i < NUM_ID_PAKS) {
        return qtrue;
    }
    return qfalse;
}

/*
================
FS_ComparePaks

----------------
dlstring == qtrue

Returns a list of pak files that we should download from the server. They all get stored
in the current gamedir and an FS_Restart will be fired up after we download them all.

The string is the format:

@remotename@localname [repeat]

static int      fs_numServerReferencedPaks;
static int      fs_serverReferencedPaks[MAX_SEARCH_PATHS];
static char     *fs_serverReferencedPakNames[MAX_SEARCH_PATHS];

----------------
dlstring == qfalse

we are not interested in a download string format, we want something human-readable
(this is used for diagnostics while connecting to a pure server)

================
*/
qboolean FS_ComparePaks( char *neededpaks, int len, qboolean dlstring ) {
    searchpath_t    *sp;
    qboolean havepak, badchecksum;
    int i;

    if ( !fs_numServerReferencedPaks ) {
        return qfalse; // Server didn't send any pack information along
    }

    *neededpaks = 0;

    for ( i = 0 ; i < fs_numServerReferencedPaks ; i++ ) {
        // Ok, see if we have this pak file
        badchecksum = qfalse;
        havepak = qfalse;

        // never autodownload any of the id paks
        if ( FS_idPak(fs_serverReferencedPakNames[i], "baseq3") || FS_idPak(fs_serverReferencedPakNames[i], "missionpack") ) {
            continue;
        }

        for ( sp = fs_searchpaths ; sp ; sp = sp->next ) {
            if ( sp->pack && sp->pack->checksum == fs_serverReferencedPaks[i] ) {
                havepak = qtrue; // This is it!
                break;
            }
        }

        if ( !havepak && fs_serverReferencedPakNames[i] && *fs_serverReferencedPakNames[i] ) { 
            // Don't got it

      if (dlstring)
      {
        // Remote name
        Q_strcat( neededpaks, len, "@");
        Q_strcat( neededpaks, len, fs_serverReferencedPakNames[i] );
        Q_strcat( neededpaks, len, ".pk3" );

        // Local name
        Q_strcat( neededpaks, len, "@");
        // Do we have one with the same name?
        if ( FS_SV_FileExists( va( "%s.pk3", fs_serverReferencedPakNames[i] ) ) )
        {
          char st[MAX_ZPATH];
          // We already have one called this, we need to download it to another name
          // Make something up with the checksum in it
          Com_sprintf( st, sizeof( st ), "%s.%08x.pk3", fs_serverReferencedPakNames[i], fs_serverReferencedPaks[i] );
          Q_strcat( neededpaks, len, st );
        } else
        {
          Q_strcat( neededpaks, len, fs_serverReferencedPakNames[i] );
          Q_strcat( neededpaks, len, ".pk3" );
        }
      }
      else
      {
        Q_strcat( neededpaks, len, fs_serverReferencedPakNames[i] );
              Q_strcat( neededpaks, len, ".pk3" );
        // Do we have one with the same name?
        if ( FS_SV_FileExists( va( "%s.pk3", fs_serverReferencedPakNames[i] ) ) )
        {
          Q_strcat( neededpaks, len, " (local file exists with wrong checksum)");
        }
        Q_strcat( neededpaks, len, "\n");
      }
        }
    }

    if ( *neededpaks ) {
        return qtrue;
    }

    return qfalse; // We have them all
}

/*
================
FS_Shutdown

Frees all resources and closes all files
================
*/
void FS_Shutdown( qboolean closemfp ) {
    searchpath_t    *p, *next;
    int i;

    for(i = 0; i < MAX_FILE_HANDLES; i++) {
        if (fsh[i].fileSize) {
            FS_FCloseFile(i);
        }
    }

    // free everything
    for ( p = fs_searchpaths ; p ; p = next ) {
        next = p->next;

        if ( p->pack ) {
            unzClose(p->pack->handle);
            Z_Free( p->pack->buildBuffer );
            Z_Free( p->pack );
        }
        if ( p->dir ) {
            Z_Free( p->dir );
        }
        Z_Free( p );
    }

    // any FS_ calls will now be an error until reinitialized
    fs_searchpaths = NULL;

    Cmd_RemoveCommand( "path" );
    Cmd_RemoveCommand( "dir" );
    Cmd_RemoveCommand( "fdir" );
    Cmd_RemoveCommand( "touchFile" );

#ifdef FS_MISSING
    if (closemfp) {
        fclose(missingFiles);
    }
#endif
}

void Com_AppendCDKey( const char *filename );
void Com_ReadCDKey( const char *filename );
 
/*
================
FS_ReorderPurePaks
NOTE TTimo: the reordering that happens here is not reflected in the cvars (\cvarlist *pak*)
  this can lead to misleading situations, see https://zerowing.idsoftware.com/bugzilla/show_bug.cgi?id=540
================
*/
static void FS_ReorderPurePaks()
{
    searchpath_t *s;
    int i;
    searchpath_t **p_insert_index, // for linked list reordering
        **p_previous; // when doing the scan
    
    // only relevant when connected to pure server
    if ( !fs_numServerPaks )
        return;
    
    fs_reordered = qfalse;
    
    p_insert_index = &fs_searchpaths; // we insert in order at the beginning of the list 
    for ( i = 0 ; i < fs_numServerPaks ; i++ ) {
        p_previous = p_insert_index; // track the pointer-to-current-item
        for (s = *p_insert_index; s; s = s->next) {
            // the part of the list before p_insert_index has been sorted already
            if (s->pack && fs_serverPaks[i] == s->pack->checksum) {
                fs_reordered = qtrue;
                // move this element to the insert list
                *p_previous = s->next;
                s->next = *p_insert_index;
                *p_insert_index = s;
                // increment insert list
                p_insert_index = &s->next;
                break; // iterate to next server pack
            }
            p_previous = &s->next; 
        }
    }
}

/*
================
FS_Startup
================
*/
static void FS_Startup( const char *gameName ) {
        const char *homePath;
    cvar_t  *fs;

    Com_Printf( "----- FS_Startup -----\n" );

    fs_debug = Cvar_Get( "fs_debug", "0", 0 );
    fs_copyfiles = Cvar_Get( "fs_copyfiles", "0", CVAR_INIT );
    fs_cdpath = Cvar_Get ("fs_cdpath", Sys_DefaultCDPath(), CVAR_INIT );
    fs_basepath = Cvar_Get ("fs_basepath", Sys_DefaultInstallPath(), CVAR_INIT );
    fs_basegame = Cvar_Get ("fs_basegame", "", CVAR_INIT );
  homePath = Sys_DefaultHomePath();
  if (!homePath || !homePath[0]) {
        homePath = fs_basepath->string;
    }
    fs_homepath = Cvar_Get ("fs_homepath", homePath, CVAR_INIT );
    fs_gamedirvar = Cvar_Get ("fs_game", "", CVAR_INIT|CVAR_SYSTEMINFO );
    fs_restrict = Cvar_Get ("fs_restrict", "", CVAR_INIT );

    // add search path elements in reverse priority order
    if (fs_cdpath->string[0]) {
        FS_AddGameDirectory( fs_cdpath->string, gameName );
    }
    if (fs_basepath->string[0]) {
        FS_AddGameDirectory( fs_basepath->string, gameName );
    }
  // fs_homepath is somewhat particular to *nix systems, only add if relevant
  // NOTE: same filtering below for mods and basegame
    if (fs_basepath->string[0] && Q_stricmp(fs_homepath->string,fs_basepath->string)) {
        FS_AddGameDirectory ( fs_homepath->string, gameName );
    }
        
    // check for additional base game so mods can be based upon other mods
    if ( fs_basegame->string[0] && !Q_stricmp( gameName, BASEGAME ) && Q_stricmp( fs_basegame->string, gameName ) ) {
        if (fs_cdpath->string[0]) {
            FS_AddGameDirectory(fs_cdpath->string, fs_basegame->string);
        }
        if (fs_basepath->string[0]) {
            FS_AddGameDirectory(fs_basepath->string, fs_basegame->string);
        }
        if (fs_homepath->string[0] && Q_stricmp(fs_homepath->string,fs_basepath->string)) {
            FS_AddGameDirectory(fs_homepath->string, fs_basegame->string);
        }
    }

    // check for additional game folder for mods
    if ( fs_gamedirvar->string[0] && !Q_stricmp( gameName, BASEGAME ) && Q_stricmp( fs_gamedirvar->string, gameName ) ) {
        if (fs_cdpath->string[0]) {
            FS_AddGameDirectory(fs_cdpath->string, fs_gamedirvar->string);
        }
        if (fs_basepath->string[0]) {
            FS_AddGameDirectory(fs_basepath->string, fs_gamedirvar->string);
        }
        if (fs_homepath->string[0] && Q_stricmp(fs_homepath->string,fs_basepath->string)) {
            FS_AddGameDirectory(fs_homepath->string, fs_gamedirvar->string);
        }
    }

    Com_ReadCDKey( "baseq3" );
    fs = Cvar_Get ("fs_game", "", CVAR_INIT|CVAR_SYSTEMINFO );
    if (fs && fs->string[0] != 0) {
        Com_AppendCDKey( fs->string );
    }

    // add our commands
    Cmd_AddCommand ("path", FS_Path_f);
    Cmd_AddCommand ("dir", FS_Dir_f );
    Cmd_AddCommand ("fdir", FS_NewDir_f );
    Cmd_AddCommand ("touchFile", FS_TouchFile_f );

    // https://zerowing.idsoftware.com/bugzilla/show_bug.cgi?id=506
    // reorder the pure pk3 files according to server order
    FS_ReorderPurePaks();
    
    // print the current search paths
    FS_Path_f();

    fs_gamedirvar->modified = qfalse; // We just loaded, it's not modified

    Com_Printf( "----------------------\n" );

#ifdef FS_MISSING
    if (missingFiles == NULL) {
        missingFiles = fopen( "\\missing.txt", "ab" );
    }
#endif
    Com_Printf( "%d files in pk3 files\n", fs_packFiles );
}


/*
===================
FS_SetRestrictions

Looks for product keys and restricts media add on ability
if the full version is not found
===================
*/
static void FS_SetRestrictions( void ) {
    searchpath_t    *path;

#ifndef PRE_RELEASE_DEMO
    char    *productId;

    // if fs_restrict is set, don't even look for the id file,
    // which allows the demo release to be tested even if
    // the full game is present
    if ( !fs_restrict->integer ) {
        // look for the full game id
        FS_ReadFile( "productid.txt", (void **)&productId );
        if ( productId ) {
            // check against the hardcoded string
            int     seed, i;

            seed = 5000;
            for ( i = 0 ; i < sizeof( fs_scrambledProductId ) ; i++ ) {
                if ( ( fs_scrambledProductId[i] ^ (seed&255) ) != productId[i] ) {
                    break;
                }
                seed = (69069 * seed + 1);
            }

            FS_FreeFile( productId );

            if ( i == sizeof( fs_scrambledProductId ) ) {
                return; // no restrictions
            }
            Com_Error( ERR_FATAL, "Invalid product identification" );
        }
    }
#endif
    Cvar_Set( "fs_restrict", "1" );

    Com_Printf( "\nRunning in restricted demo mode.\n\n" );

    // restart the filesystem with just the demo directory
    FS_Shutdown(qfalse);
    FS_Startup( DEMOGAME );

    // make sure that the pak file has the header checksum we expect
    for ( path = fs_searchpaths ; path ; path = path->next ) {
        if ( path->pack ) {
            // a tiny attempt to keep the checksum from being scannable from the exe
            if ( (path->pack->checksum ^ 0x02261994u) != (DEMO_PAK_CHECKSUM ^ 0x02261994u) ) {
                Com_Error( ERR_FATAL, "Corrupted pak0.pk3: %u", path->pack->checksum );
            }
        }
    }
}

/*
=====================
FS_GamePureChecksum

Returns the checksum of the pk3 from which the server loaded the qagame.qvm
=====================
*/
const char *FS_GamePureChecksum( void ) {
    static char info[MAX_STRING_TOKENS];
    searchpath_t *search;

    info[0] = 0;

    for ( search = fs_searchpaths ; search ; search = search->next ) {
        // is the element a pak file?
        if ( search->pack ) {
            if (search->pack->referenced & FS_QAGAME_REF) {
                Com_sprintf(info, sizeof(info), "%d", search->pack->checksum);
            }
        }
    }

    return info;
}

/*
=====================
FS_LoadedPakChecksums

Returns a space separated string containing the checksums of all loaded pk3 files.
Servers with sv_pure set will get this string and pass it to clients.
=====================
*/
const char *FS_LoadedPakChecksums( void ) {
    static char info[BIG_INFO_STRING];
    searchpath_t    *search;

    info[0] = 0;

    for ( search = fs_searchpaths ; search ; search = search->next ) {
        // is the element a pak file? 
        if ( !search->pack ) {
            continue;
        }

        Q_strcat( info, sizeof( info ), va("%i ", search->pack->checksum ) );
    }

    return info;
}

/*
=====================
FS_LoadedPakNames

Returns a space separated string containing the names of all loaded pk3 files.
Servers with sv_pure set will get this string and pass it to clients.
=====================
*/
const char *FS_LoadedPakNames( void ) {
    static char info[BIG_INFO_STRING];
    searchpath_t    *search;

    info[0] = 0;

    for ( search = fs_searchpaths ; search ; search = search->next ) {
        // is the element a pak file?
        if ( !search->pack ) {
            continue;
        }

        if (*info) {
            Q_strcat(info, sizeof( info ), " " );
        }
        Q_strcat( info, sizeof( info ), search->pack->pakBasename );
    }

    return info;
}

/*
=====================
FS_LoadedPakPureChecksums

Returns a space separated string containing the pure checksums of all loaded pk3 files.
Servers with sv_pure use these checksums to compare with the checksums the clients send
back to the server.
=====================
*/
const char *FS_LoadedPakPureChecksums( void ) {
    static char info[BIG_INFO_STRING];
    searchpath_t    *search;

    info[0] = 0;

    for ( search = fs_searchpaths ; search ; search = search->next ) {
        // is the element a pak file? 
        if ( !search->pack ) {
            continue;
        }

        Q_strcat( info, sizeof( info ), va("%i ", search->pack->pure_checksum ) );
    }

    return info;
}

/*
=====================
FS_ReferencedPakChecksums

Returns a space separated string containing the checksums of all referenced pk3 files.
The server will send this to the clients so they can check which files should be auto-downloaded. 
=====================
*/
const char *FS_ReferencedPakChecksums( void ) {
    static char info[BIG_INFO_STRING];
    searchpath_t *search;

    info[0] = 0;


    for ( search = fs_searchpaths ; search ; search = search->next ) {
        // is the element a pak file?
        if ( search->pack ) {
            if (search->pack->referenced || Q_stricmpn(search->pack->pakGamename, BASEGAME, strlen(BASEGAME))) {
                Q_strcat( info, sizeof( info ), va("%i ", search->pack->checksum ) );
            }
        }
    }

    return info;
}

/*
=====================
FS_ReferencedPakPureChecksums

Returns a space separated string containing the pure checksums of all referenced pk3 files.
Servers with sv_pure set will get this string back from clients for pure validation 

The string has a specific order, "cgame ui @ ref1 ref2 ref3 ..."
=====================
*/
const char *FS_ReferencedPakPureChecksums( void ) {
    static char info[BIG_INFO_STRING];
    searchpath_t    *search;
    int nFlags, numPaks, checksum;

    info[0] = 0;

    checksum = fs_checksumFeed;
    numPaks = 0;
    for (nFlags = FS_CGAME_REF; nFlags; nFlags = nFlags >> 1) {
        if (nFlags & FS_GENERAL_REF) {
            // add a delimter between must haves and general refs
            //Q_strcat(info, sizeof(info), "@ ");
            info[strlen(info)+1] = '\0';
            info[strlen(info)+2] = '\0';
            info[strlen(info)] = '@';
            info[strlen(info)] = ' ';
        }
        for ( search = fs_searchpaths ; search ; search = search->next ) {
            // is the element a pak file and has it been referenced based on flag?
            if ( search->pack && (search->pack->referenced & nFlags)) {
                Q_strcat( info, sizeof( info ), va("%i ", search->pack->pure_checksum ) );
                if (nFlags & (FS_CGAME_REF | FS_UI_REF)) {
                    break;
                }
                checksum ^= search->pack->pure_checksum;
                numPaks++;
            }
        }
        if (fs_fakeChkSum != 0) {
            // only added if a non-pure file is referenced
            Q_strcat( info, sizeof( info ), va("%i ", fs_fakeChkSum ) );
        }
    }
    // last checksum is the encoded number of referenced pk3s
    checksum ^= numPaks;
    Q_strcat( info, sizeof( info ), va("%i ", checksum ) );

    return info;
}

/*
=====================
FS_ReferencedPakNames

Returns a space separated string containing the names of all referenced pk3 files.
The server will send this to the clients so they can check which files should be auto-downloaded. 
=====================
*/
const char *FS_ReferencedPakNames( void ) {
    static char info[BIG_INFO_STRING];
    searchpath_t    *search;

    info[0] = 0;

    // we want to return ALL pk3's from the fs_game path
    // and referenced one's from baseq3
    for ( search = fs_searchpaths ; search ; search = search->next ) {
        // is the element a pak file?
        if ( search->pack ) {
            if (*info) {
                Q_strcat(info, sizeof( info ), " " );
            }
            if (search->pack->referenced || Q_stricmpn(search->pack->pakGamename, BASEGAME, strlen(BASEGAME))) {
                Q_strcat( info, sizeof( info ), search->pack->pakGamename );
                Q_strcat( info, sizeof( info ), "/" );
                Q_strcat( info, sizeof( info ), search->pack->pakBasename );
            }
        }
    }

    return info;
}

/*
=====================
FS_ClearPakReferences
=====================
*/
void FS_ClearPakReferences( int flags ) {
    searchpath_t *search;

    if ( !flags ) {
        flags = -1;
    }
    for ( search = fs_searchpaths; search; search = search->next ) {
        // is the element a pak file and has it been referenced?
        if ( search->pack ) {
            search->pack->referenced &= ~flags;
        }
    }
}


/*
=====================
FS_PureServerSetLoadedPaks

If the string is empty, all data sources will be allowed.
If not empty, only pk3 files that match one of the space
separated checksums will be checked for files, with the
exception of .cfg and .dat files.
=====================
*/
void FS_PureServerSetLoadedPaks( const char *pakSums, const char *pakNames ) {
    int     i, c, d;

    Cmd_TokenizeString( pakSums );

    c = Cmd_Argc();
    if ( c > MAX_SEARCH_PATHS ) {
        c = MAX_SEARCH_PATHS;
    }

    fs_numServerPaks = c;

    for ( i = 0 ; i < c ; i++ ) {
        fs_serverPaks[i] = atoi( Cmd_Argv( i ) );
    }

    if (fs_numServerPaks) {
        Com_DPrintf( "Connected to a pure server.\n" );
    }
    else
    {
        if (fs_reordered)
        {
            // https://zerowing.idsoftware.com/bugzilla/show_bug.cgi?id=540
            // force a restart to make sure the search order will be correct
            Com_DPrintf( "FS search reorder is required\n" );
            FS_Restart(fs_checksumFeed);
            return;
        }
    }

    for ( i = 0 ; i < c ; i++ ) {
        if (fs_serverPakNames[i]) {
            Z_Free(fs_serverPakNames[i]);
        }
        fs_serverPakNames[i] = NULL;
    }
    if ( pakNames && *pakNames ) {
        Cmd_TokenizeString( pakNames );

        d = Cmd_Argc();
        if ( d > MAX_SEARCH_PATHS ) {
            d = MAX_SEARCH_PATHS;
        }

        for ( i = 0 ; i < d ; i++ ) {
            fs_serverPakNames[i] = CopyString( Cmd_Argv( i ) );
        }
    }
}

/*
=====================
FS_PureServerSetReferencedPaks

The checksums and names of the pk3 files referenced at the server
are sent to the client and stored here. The client will use these
checksums to see if any pk3 files need to be auto-downloaded. 
=====================
*/
void FS_PureServerSetReferencedPaks( const char *pakSums, const char *pakNames ) {
    int     i, c, d;

    Cmd_TokenizeString( pakSums );

    c = Cmd_Argc();
    if ( c > MAX_SEARCH_PATHS ) {
        c = MAX_SEARCH_PATHS;
    }

    fs_numServerReferencedPaks = c;

    for ( i = 0 ; i < c ; i++ ) {
        fs_serverReferencedPaks[i] = atoi( Cmd_Argv( i ) );
    }

    for ( i = 0 ; i < c ; i++ ) {
        if (fs_serverReferencedPakNames[i]) {
            Z_Free(fs_serverReferencedPakNames[i]);
        }
        fs_serverReferencedPakNames[i] = NULL;
    }
    if ( pakNames && *pakNames ) {
        Cmd_TokenizeString( pakNames );

        d = Cmd_Argc();
        if ( d > MAX_SEARCH_PATHS ) {
            d = MAX_SEARCH_PATHS;
        }

        for ( i = 0 ; i < d ; i++ ) {
            fs_serverReferencedPakNames[i] = CopyString( Cmd_Argv( i ) );
        }
    }
}

/*
================
FS_InitFilesystem

Called only at inital startup, not when the filesystem
is resetting due to a game change
================
*/
void FS_InitFilesystem( void ) {
    // allow command line parms to override our defaults
    // we have to specially handle this, because normal command
    // line variable sets don't happen until after the filesystem
    // has already been initialized
    Com_StartupVariable( "fs_cdpath" );
    Com_StartupVariable( "fs_basepath" );
    Com_StartupVariable( "fs_homepath" );
    Com_StartupVariable( "fs_game" );
    Com_StartupVariable( "fs_copyfiles" );
    Com_StartupVariable( "fs_restrict" );

    // try to start up normally
    FS_Startup( BASEGAME );

    // see if we are going to allow add-ons
    FS_SetRestrictions();

    // if we can't find default.cfg, assume that the paths are
    // busted and error out now, rather than getting an unreadable
    // graphics screen when the font fails to load
    if ( FS_ReadFile( "default.cfg", NULL ) <= 0 ) {
        Com_Error( ERR_FATAL, "Couldn't load default.cfg" );
        // bk001208 - SafeMode see below, FIXME?
    }

    Q_strncpyz(lastValidBase, fs_basepath->string, sizeof(lastValidBase));
    Q_strncpyz(lastValidGame, fs_gamedirvar->string, sizeof(lastValidGame));

  // bk001208 - SafeMode see below, FIXME?
}


/*
================
FS_Restart
================
*/
void FS_Restart( int checksumFeed ) {

    // free anything we currently have loaded
    FS_Shutdown(qfalse);

    // set the checksum feed
    fs_checksumFeed = checksumFeed;

    // clear pak references
    FS_ClearPakReferences(0);

    // try to start up normally
    FS_Startup( BASEGAME );

    // see if we are going to allow add-ons
    FS_SetRestrictions();

    // if we can't find default.cfg, assume that the paths are
    // busted and error out now, rather than getting an unreadable
    // graphics screen when the font fails to load
    if ( FS_ReadFile( "default.cfg", NULL ) <= 0 ) {
        // this might happen when connecting to a pure server not using BASEGAME/pak0.pk3
        // (for instance a TA demo server)
        if (lastValidBase[0]) {
            FS_PureServerSetLoadedPaks("", "");
            Cvar_Set("fs_basepath", lastValidBase);
            Cvar_Set("fs_gamedirvar", lastValidGame);
            lastValidBase[0] = '\0';
            lastValidGame[0] = '\0';
            Cvar_Set( "fs_restrict", "0" );
            FS_Restart(checksumFeed);
            Com_Error( ERR_DROP, "Invalid game folder\n" );
            return;
        }
        Com_Error( ERR_FATAL, "Couldn't load default.cfg" );
    }

    // bk010116 - new check before safeMode
    if ( Q_stricmp(fs_gamedirvar->string, lastValidGame) ) {
        // skip the q3config.cfg if "safe" is on the command line
        if ( !Com_SafeMode() ) {
            Cbuf_AddText ("exec q3config.cfg\n");
        }
    }

    Q_strncpyz(lastValidBase, fs_basepath->string, sizeof(lastValidBase));
    Q_strncpyz(lastValidGame, fs_gamedirvar->string, sizeof(lastValidGame));

}

/*
=================
FS_ConditionalRestart
restart if necessary
=================
*/
qboolean FS_ConditionalRestart( int checksumFeed ) {
    if( fs_gamedirvar->modified || checksumFeed != fs_checksumFeed ) {
        FS_Restart( checksumFeed );
        return qtrue;
    }
    return qfalse;
}

/*
========================================================================================

Handle based file calls for virtual machines

========================================================================================
*/

int     FS_FOpenFileByMode( const char *qpath, fileHandle_t *f, fsMode_t mode ) {
    int     r;
    qboolean    sync;

    sync = qfalse;

    switch( mode ) {
    case FS_READ:
        r = FS_FOpenFileRead( qpath, f, qtrue );
        break;
    case FS_WRITE:
        *f = FS_FOpenFileWrite( qpath );
        r = 0;
        if (*f == 0) {
            r = -1;
        }
        break;
    case FS_APPEND_SYNC:
        sync = qtrue;
    case FS_APPEND:
        *f = FS_FOpenFileAppend( qpath );
        r = 0;
        if (*f == 0) {
            r = -1;
        }
        break;
    default:
        Com_Error( ERR_FATAL, "FSH_FOpenFile: bad mode" );
        return -1;
    }

    if (!f) {
        return r;
    }

    if ( *f ) {
        if (fsh[*f].zipFile == qtrue) {
            fsh[*f].baseOffset = unztell(fsh[*f].handleFiles.file.z);
        } else {
            fsh[*f].baseOffset = ftell(fsh[*f].handleFiles.file.o);
        }
        fsh[*f].fileSize = r;
        fsh[*f].streamed = qfalse;

        if (mode == FS_READ) {
            Sys_BeginStreamedFile( *f, 0x4000 );
            fsh[*f].streamed = qtrue;
        }
    }
    fsh[*f].handleSync = sync;

    return r;
}

int     FS_FTell( fileHandle_t f ) {
    int pos;
    if (fsh[f].zipFile == qtrue) {
        pos = unztell(fsh[f].handleFiles.file.z);
    } else {
        pos = ftell(fsh[f].handleFiles.file.o);
    }
    return pos;
}

void    FS_Flush( fileHandle_t f ) {
    fflush(fsh[f].handleFiles.file.o);
}

---