quakeforge/libs/util/quakefs.c

/*
	quakefs.c

	virtual filesystem functions

	Copyright (C) 1996-1997  Id Software, Inc.

	This program 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.

	This program 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 this program; if not, write to:

		Free Software Foundation, Inc.
		59 Temple Place - Suite 330
		Boston, MA  02111-1307, USA

*/
static const char rcsid[] = 
	"$Id$";

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#ifdef HAVE_STRING_H
# include <string.h>
#endif
#ifdef HAVE_STRINGS_H
# include <strings.h>
#endif
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif

#include <ctype.h>
#include <dirent.h>
#include <fcntl.h>
#include <stdlib.h>
#include <stdarg.h>

#ifdef HAVE_FNMATCH_H
# define model_t sunmodel_t
# include <fnmatch.h>
# undef model_t
#else
# ifdef WIN32
# include "fnmatch.h"
# endif
#endif

#ifdef HAVE_IO_H
# include <io.h>
#endif

#ifdef _MSC_VER
# define _POSIX_
#endif

#include <limits.h>

#include "QF/cmd.h"
#include "QF/cvar.h"
#include "QF/hash.h"
#include "QF/qargs.h"
#include "QF/qendian.h"
#include "QF/qtypes.h"
#include "QF/sys.h"
#include "QF/va.h"
#include "QF/vfs.h"
#include "QF/zone.h"

#include "compat.h"

#ifndef HAVE_FNMATCH_PROTO
int         fnmatch (const char *__pattern, const char *__string, int __flags);
#endif

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

	The "user directory" is the path to the directory holding the quake.exe
	and all game directories.  This can be overridden with the "fs_sharepath"
	and "fs_userpath" cvars to allow code debugging in a different directory.
	The base directory is only used during filesystem initialization.

	The "game directory" is the first tree on the search path and directory
	that all generated files (savegames, screenshots, demos, config files)
	will be saved to.  This can be overridden with the "-game" command line
	parameter.  The game directory can never be changed while quake is
	executing.  This is a precacution against having a malicious server
	instruct clients to write files over areas they shouldn't.

	The "cache directory" is only used during development to save network
	bandwidth, especially over ISDN / T1 lines.  If there is a cache directory
	specified, when a file is found by the normal search path, it will be
	mirrored into the cache directory, then opened there.
*/

/*
	QUAKE FILESYSTEM
*/

char        gamedirfile[MAX_OSPATH];

cvar_t     *fs_userpath;
cvar_t     *fs_sharepath;
cvar_t     *fs_basegame;
cvar_t     *fs_skinbase;

int         com_filesize;

/*
	Structs for pack files on disk
*/
typedef struct {
	char        name[56];
	int         filepos, filelen;
} dpackfile_t;

typedef struct {
	char        id[4];
	int         dirofs;
	int         dirlen;
} dpackheader_t;

#define	MAX_FILES_IN_PACK	2048

char        com_gamedir[MAX_OSPATH];

searchpath_t *com_searchpaths;
searchpath_t *com_base_searchpaths;		// without gamedirs


void
COM_FileBase (const char *in, char *out)
{
	const char *slash, *dot;
	const char *s;

	slash = in;
	dot = NULL;
	s = in;
	while (*s) {
		if (*s == '/')
			slash = s + 1;
		if (*s == '.')
			dot = s;
		s++;
	}
	if (dot == NULL)
		dot = s;
	if (dot - slash < 2)
		strcpy (out, "?model?");
	else {
		while (slash < dot)
			*out++ = *slash++;
		*out++ = 0;
	}
}


int
COM_filelength (VFile *f)
{
	int         pos;
	int         end;

	pos = Qtell (f);
	Qseek (f, 0, SEEK_END);
	end = Qtell (f);
	Qseek (f, pos, SEEK_SET);

	return end;
}


int
COM_FileOpenRead (char *path, VFile **hndl)
{
	VFile      *f;

	f = Qopen (path, "rbz");
	if (!f) {
		*hndl = NULL;
		return -1;
	}
	*hndl = f;

	return COM_filelength (f);
}


void
COM_Path_f (void)
{
	searchpath_t *s;

	Sys_Printf ("Current search path:\n");
	for (s = com_searchpaths; s; s = s->next) {
		if (s == com_base_searchpaths)
			Sys_Printf ("----------\n");
		if (s->pack)
			Sys_Printf ("%s (%i files)\n", s->pack->filename,
						s->pack->numfiles);
		else
			Sys_Printf ("%s\n", s->filename);
	}
}

/*
	COM_WriteFile

	The filename will be prefixed by the current game directory
*/
void
COM_WriteFile (const char *filename, void *data, int len)
{
	VFile      *f;
	char        name[MAX_OSPATH];

	snprintf (name, sizeof (name), "%s/%s", com_gamedir, filename);

	f = Qopen (name, "wb");
	if (!f) {
		Sys_mkdir (com_gamedir);
		f = Qopen (name, "wb");
		if (!f)
			Sys_Error ("Error opening %s", filename);
	}

	Sys_Printf ("COM_WriteFile: %s\n", name);
	Qwrite (f, data, len);
	Qclose (f);
}

/*
	COM_WriteBuffers

	The filename will be prefixed by the current game directory
*/
void
COM_WriteBuffers (const char *filename, int count, ...)
{
	VFile      *f;
	char        name[MAX_OSPATH];
	va_list     args;

	va_start (args, count);

	snprintf (name, sizeof (name), "%s/%s", com_gamedir, filename);

	f = Qopen (name, "wb");
	if (!f) {
		Sys_mkdir (com_gamedir);
		f = Qopen (name, "wb");
		if (!f)
			Sys_Error ("Error opening %s", filename);
	}

	Sys_Printf ("COM_WriteBuffers: %s\n", name);
	while (count--) {
		void       *data = va_arg (args, void *);
		int         len = va_arg (args, int);

		Qwrite (f, data, len);
	}
	Qclose (f);
	va_end (args);
}

/*
	COM_CreatePath

	Only used for CopyFile and download
*/
void
COM_CreatePath (const char *path)
{
	char       *ofs;
	char        e_path[MAX_OSPATH];

	Qexpand_squiggle (path, e_path);

	for (ofs = e_path + 1; *ofs; ofs++) {
		if (*ofs == '/') {				// create the directory
			*ofs = 0;
			Sys_mkdir (e_path);
			*ofs = '/';
		}
	}
}

/*
	COM_CopyFile

	Copies a file over from the net to the local cache, creating any
	directories needed.  This is for the convenience of developers using
	ISDN from home.
*/
void
COM_CopyFile (char *netpath, char *cachepath)
{
	VFile      *in, *out;
	int         remaining, count;
	char        buf[4096];

	remaining = COM_FileOpenRead (netpath, &in);
	COM_CreatePath (cachepath);			// create directories up to the cache 
	// file
	out = Qopen (cachepath, "wb");
	if (!out)
		Sys_Error ("Error opening %s", cachepath);

	while (remaining) {
		if (remaining < sizeof (buf))
			count = remaining;
		else
			count = sizeof (buf);
		Qread (in, buf, count);
		Qwrite (out, buf, count);
		remaining -= count;
	}

	Qclose (in);
	Qclose (out);
}

VFile      *
COM_OpenRead (const char *path, int offs, int len, int zip)
{
	int         fd = open (path, O_RDONLY);
	unsigned char id[2];
	unsigned char len_bytes[4];

	if (fd == -1) {
		Sys_Error ("Couldn't open %s", path);
		return 0;
	}
	if (offs < 0 || len < 0) {
		// normal file
		offs = 0;
		len = lseek (fd, 0, SEEK_END);
		lseek (fd, 0, SEEK_SET);
	}
	lseek (fd, offs, SEEK_SET);
	if (zip) {
		read (fd, id, 2);
		if (id[0] == 0x1f && id[1] == 0x8b) {
			lseek (fd, offs + len - 4, SEEK_SET);
			read (fd, len_bytes, 4);
			len = ((len_bytes[3] << 24)
				   | (len_bytes[2] << 16)
				   | (len_bytes[1] << 8)
				   | (len_bytes[0]));
		}
	}
	lseek (fd, offs, SEEK_SET);
	com_filesize = len;

#ifdef WIN32
	setmode (fd, O_BINARY);
#endif
	if (zip)
		return Qdopen (fd, "rbz");
	else
		return Qdopen (fd, "rb");
}

/*
	contains_updir

	Checks if a string contains an updir ('..'), either at the ends or
	surrounded by slashes ('/').  Doesn't check for leading slash.
*/
int
contains_updir (const char *filename)
{
	int i;

	if (filename[0] == 0 || filename [1] == 0)
                return 0;

	// FIXME: maybe I should handle alternate seperators?
	for (i = 0; filename[i+1]; i++) {
		if (!(i == 0 || filename[i-1] == '/')           // beginning of string
														// or first slash
		    || filename[i] != '.'                       // first dot
		    || filename[i+1] != '.')                    // second dot
			continue;

		if (filename[i+2] == 0 || filename[i+2] == '/')
			// end of string or second slash
			return 1;
	}
	return 0;
}

int file_from_pak; // global indicating file came from pack file ZOID

/*
	COM_FOpenFile

	Finds the file in the search path.
	Sets com_filesize and one of handle or file
*/
int
_COM_FOpenFile (const char *filename, VFile **gzfile, char *foundname, int zip)
{
	searchpath_t *search;
	char        netpath[MAX_OSPATH];
	int         findtime;

#ifdef HAVE_ZLIB
	char        gzfilename[MAX_OSPATH];
	int         filenamelen;

	filenamelen = strlen (filename);
	strncpy (gzfilename, filename, sizeof (gzfilename));
	strncat (gzfilename, ".gz", sizeof (gzfilename) - strlen (gzfilename));
#endif

	file_from_pak = 0;

	// make sure they're not trying to do wierd stuff with our private files
	if (contains_updir(filename)) {
		Sys_Printf ("FindFile: %s: attempt to escape directory tree!\n", filename);
		goto error;
	}

	// search through the path, one element at a time
	for (search = com_searchpaths; search; search = search->next) {
		// is the element a pak file?
		if (search->pack) {
			packfile_t *packfile;

			packfile = (packfile_t *) Hash_Find (search->pack->file_hash,
												 filename);
#ifdef HAVE_ZLIB
			if (!packfile)
				packfile = (packfile_t *) Hash_Find (search->pack->file_hash,
													 gzfilename);
#endif
			if (packfile) {
				Sys_DPrintf ("PackFile: %s : %s\n", search->pack->filename,
							 packfile->name);
				// open a new file on the pakfile
				strncpy (foundname, packfile->name, MAX_OSPATH);
				*gzfile =
					COM_OpenRead (search->pack->filename, packfile->filepos,
								  packfile->filelen, zip);
				file_from_pak = 1;
				return com_filesize;
			}
		} else {
			// check a file in the directory tree
			snprintf (netpath, sizeof (netpath), "%s%s%s", search->filename,
					  search->filename[0] ? "/" : "", filename);

			strncpy (foundname, filename, MAX_OSPATH);
			findtime = Sys_FileTime (netpath);
			if (findtime == -1) {
#ifdef HAVE_ZLIB
				strncpy (foundname, gzfilename, MAX_OSPATH);
				snprintf (netpath, sizeof (netpath), "%s%s%s",
						  search->filename,
						  search->filename[0] ? "/" : "", gzfilename);
				findtime = Sys_FileTime (netpath);
				if (findtime == -1)
#endif
					continue;
			}

			Sys_DPrintf ("FindFile: %s\n", netpath);

			*gzfile = COM_OpenRead (netpath, -1, -1, zip);
			return com_filesize;
		}

	}

	Sys_DPrintf ("FindFile: can't find %s\n", filename);
error:
	*gzfile = NULL;
	com_filesize = -1;
	return -1;
}

int
COM_FOpenFile (const char *filename, VFile **gzfile)
{
	char        foundname[MAX_OSPATH];

	return _COM_FOpenFile (filename, gzfile, foundname, 1);
}

cache_user_t *loadcache;
byte       *loadbuf;
int         loadsize;

/*
	COM_LoadFile

	Filename are relative to the quake directory.
	Allways appends a 0 byte to the loaded data.
*/
byte       *
COM_LoadFile (const char *path, int usehunk)
{
	VFile      *h;
	byte       *buf = NULL;
	char        base[32];
	int         len;

	// look for it in the filesystem or pack files
	len = com_filesize = COM_FOpenFile (path, &h);
	if (!h)
		return NULL;

	// extract the filename base name for hunk tag
	COM_FileBase (path, base);

	if (usehunk == 1)
		buf = Hunk_AllocName (len + 1, base);
	else if (usehunk == 2)
		buf = Hunk_TempAlloc (len + 1);
	else if (usehunk == 0)
		buf = calloc (1, len + 1);
	else if (usehunk == 3)
		buf = Cache_Alloc (loadcache, len + 1, base);
	else if (usehunk == 4) {
		if (len + 1 > loadsize)
			buf = Hunk_TempAlloc (len + 1);
		else
			buf = loadbuf;
	} else
		Sys_Error ("COM_LoadFile: bad usehunk");

	if (!buf)
		Sys_Error ("COM_LoadFile: not enough space for %s", path);

	buf[len] = 0;
	Qread (h, buf, len);
	Qclose (h);

	return buf;
}

byte       *
COM_LoadHunkFile (const char *path)
{
	return COM_LoadFile (path, 1);
}

byte       *
COM_LoadTempFile (const char *path)
{
	return COM_LoadFile (path, 2);
}

void
COM_LoadCacheFile (const char *path, struct cache_user_s *cu)
{
	loadcache = cu;
	COM_LoadFile (path, 3);
}

// uses temp hunk if larger than bufsize
byte       *
COM_LoadStackFile (const char *path, void *buffer, int bufsize)
{
	byte       *buf;

	loadbuf = (byte *) buffer;
	loadsize = bufsize;
	buf = COM_LoadFile (path, 4);

	return buf;
}

static const char *
pack_get_key (void *_p, void *unused)
{
	packfile_t *p = (packfile_t *) _p;

	return p->name;
}

/*
	COM_LoadPackFile

	Takes an explicit (not game tree related) path to a pak file.

	Loads the header and directory, adding the files at the beginning
	of the list so they override previous pack files.
*/
pack_t     *
COM_LoadPackFile (char *packfile)
{
	dpackheader_t header;
	int         i;
	packfile_t *newfiles;
	int         numpackfiles;
	pack_t     *pack;
	VFile      *packhandle;
	dpackfile_t info[MAX_FILES_IN_PACK];
	hashtab_t  *hash;

	if (COM_FileOpenRead (packfile, &packhandle) == -1)
		return NULL;

	Qread (packhandle, &header, sizeof (header));
	if (header.id[0] != 'P' || header.id[1] != 'A'
		|| header.id[2] != 'C' || header.id[3] != 'K')
		Sys_Error ("%s is not a packfile", packfile);
	header.dirofs = LittleLong (header.dirofs);
	header.dirlen = LittleLong (header.dirlen);

	numpackfiles = header.dirlen / sizeof (dpackfile_t);

	if (numpackfiles > MAX_FILES_IN_PACK)
		Sys_Error ("%s has %i files", packfile, numpackfiles);

	newfiles = calloc (1, numpackfiles * sizeof (packfile_t));
	hash = Hash_NewTable (1021, pack_get_key, 0, 0);

	Qseek (packhandle, header.dirofs, SEEK_SET);
	Qread (packhandle, info, header.dirlen);

	// parse the directory
	for (i = 0; i < numpackfiles; i++) {
		strcpy (newfiles[i].name, info[i].name);
		newfiles[i].filepos = LittleLong (info[i].filepos);
		newfiles[i].filelen = LittleLong (info[i].filelen);
		Hash_Add (hash, &newfiles[i]);
	}

	pack = calloc (1, sizeof (pack_t));
	strcpy (pack->filename, packfile);
	pack->handle = packhandle;
	pack->numfiles = numpackfiles;
	pack->files = newfiles;
	pack->file_hash = hash;

	Sys_Printf ("Added packfile %s (%i files)\n", packfile, numpackfiles);
	return pack;
}

#define FBLOCK_SIZE	32
#define FNAME_SIZE	MAX_OSPATH

// Note, this is /NOT/ a work-alike strcmp, this groups numbers sanely.
int
qstrcmp (char **os1, char **os2)
{
	int         in1, in2, n1, n2;
	char       *s1, *s2;

	s1 = *os1;
	s2 = *os2;

	while (1) {
		in1 = in2 = n1 = n2 = 0;

		if ((in1 = isdigit ((int) *s1)))
			n1 = strtol (s1, &s1, 10);

		if ((in2 = isdigit ((int) *s2)))
			n2 = strtol (s2, &s2, 10);

		if (in1 && in2) {
			if (n1 != n2)
				return n1 - n2;
		} else {
			if (*s1 != *s2)
				return *s1 - *s2;
			else if (*s1 == '\0')
				return *s1 - *s2;
			s1++;
			s2++;
		}
	}
}

void
COM_LoadGameDirectory (const char *dir)
{
	searchpath_t *search;
	pack_t     *pak;
	DIR        *dir_ptr;
	struct dirent *dirent;
	char      **pakfiles = NULL;
	int         i = 0, bufsize = 0, count = 0;

	Sys_DPrintf ("COM_LoadGameDirectory (\"%s\")\n", dir);

	pakfiles = calloc (1, FBLOCK_SIZE * sizeof (char *));

	bufsize += FBLOCK_SIZE;
	if (!pakfiles)
		goto COM_LoadGameDirectory_free;

	for (i = 0; i < bufsize; i++) {
		pakfiles[i] = NULL;
	}

	dir_ptr = opendir (dir);
	if (!dir_ptr)
		return;

	while ((dirent = readdir (dir_ptr))) {
		if (!fnmatch ("*.pak", dirent->d_name, 0)) {
			if (count >= bufsize) {
				bufsize += FBLOCK_SIZE;
				pakfiles = realloc (pakfiles, bufsize * sizeof (char *));

				if (!pakfiles)
					goto COM_LoadGameDirectory_free;
				for (i = count; i < bufsize; i++)
					pakfiles[i] = NULL;
			}

			pakfiles[count] = malloc (FNAME_SIZE);
			if (!pakfiles[count])
				Sys_Error ("COM_LoadGameDirectory: MemoryAllocationFailure\n");
			snprintf (pakfiles[count], FNAME_SIZE - 1, "%s/%s", dir,
					  dirent->d_name);
			pakfiles[count][FNAME_SIZE - 1] = '\0';
			count++;
		}
	}
	closedir (dir_ptr);

	// XXX WARNING!!! This is /NOT/ subtable for strcmp!!!!!
	// This passes 'void **' instead of 'char *' to the cmp function!
	qsort (pakfiles, count, sizeof (char *),
		   (int (*)(const void *, const void *)) qstrcmp);

	for (i = 0; i < count; i++) {
		pak = COM_LoadPackFile (pakfiles[i]);

		if (!pak) {
			Sys_Error (va ("Bad pakfile %s!!", pakfiles[i]));
		} else {
			search = calloc (1, sizeof (searchpath_t));
			search->pack = pak;
			search->next = com_searchpaths;
			com_searchpaths = search;
		}
	}

  COM_LoadGameDirectory_free:
	for (i = 0; i < count; i++)
		free (pakfiles[i]);
	free (pakfiles);
}

/*
	COM_AddDirectory

	Sets com_gamedir, adds the directory to the head of the path,
	then loads and adds pak1.pak pak2.pak ...
*/
void
COM_AddDirectory (const char *dir)
{
	searchpath_t *search;
	char       *p;
	char        e_dir[MAX_OSPATH];

	Qexpand_squiggle (dir, e_dir);
	dir = e_dir;

	if ((p = strrchr (dir, '/')) != NULL) {
		strcpy (gamedirfile, ++p);
		strcpy (com_gamedir, dir);
	} else {
		strcpy (gamedirfile, dir);
		strcpy (com_gamedir, va ("%s/%s", fs_userpath->string, dir));
	}

	// add the directory to the search path
	search = calloc (1, sizeof (searchpath_t));
	strcpy (search->filename, dir);
	search->next = com_searchpaths;
	com_searchpaths = search;

	// add any pak files in the format pak0.pak pak1.pak, ...
	COM_LoadGameDirectory (dir);
}

void
COM_AddGameDirectory (const char *dir)
{
	Sys_DPrintf ("COM_AddGameDirectory (\"%s/%s\")\n",
				 fs_sharepath->string, dir);

	if (strcmp (fs_sharepath->string, fs_userpath->string) != 0)
		COM_AddDirectory (va ("%s/%s", fs_sharepath->string, dir));
	COM_AddDirectory (va ("%s/%s", fs_userpath->string, dir));
}

/*
	COM_Gamedir

	Sets the gamedir and path to a different directory.
*/
void
COM_Gamedir (const char *dir)
{
	searchpath_t *next;

	if (strstr (dir, "..") || strstr (dir, "/")
		|| strstr (dir, "\\") || strstr (dir, ":")) {
		Sys_Printf ("Gamedir should be a single filename, not a path\n");
		return;
	}

	if (strcmp (gamedirfile, dir) == 0)
		return;							// still the same
	strcpy (gamedirfile, dir);

	// free up any current game dir info
	while (com_searchpaths != com_base_searchpaths) {
		if (com_searchpaths->pack) {
			Qclose (com_searchpaths->pack->handle);
			free (com_searchpaths->pack->files);
			free (com_searchpaths->pack);
		}
		next = com_searchpaths->next;
		free (com_searchpaths);
		com_searchpaths = next;
	}

	// flush all data, so it will be forced to reload
	Cache_Flush ();

	if (fs_skinbase && strcmp (dir, fs_skinbase->string) == 0)
		return;

	COM_AddGameDirectory (dir);
}

void
COM_CreateGameDirectory (const char *gamename)
{
	if (strcmp (fs_userpath->string, "."))
		COM_CreatePath (va ("%s/%s/dummy", fs_userpath->string, gamename));
	COM_AddGameDirectory (gamename);
}

void
COM_Filesystem_Init (void)
{
	int         i;

	if (!fs_sharepath->string[0]
		&& !fs_userpath->string[0]
		&& !fs_basegame->string[0]) {
		// a util (or a silly user:) are subverting the fs code
		// add the directory to the search path
		searchpath_t *search = calloc (1, sizeof (searchpath_t));
		strcpy (search->filename, "");
		search->next = com_searchpaths;
		com_searchpaths = search;
		com_base_searchpaths = com_searchpaths;
		return;
	}

	// start up with basegame->string by default
	COM_CreateGameDirectory (fs_basegame->string);

	// If we're dealing with id1, use qw too
	if (fs_skinbase && !strequal (fs_basegame->string, fs_skinbase->string)) {
		COM_CreateGameDirectory (fs_skinbase->string);
	}

	if ((i = COM_CheckParm ("-game")) && i < com_argc - 1) {
		char       *gamedirs = NULL;
		char       *where;

		gamedirs = strdup (com_argv[i + 1]);
		where = strtok (gamedirs, ",");
		while (where) {
			COM_CreateGameDirectory (where);
			where = strtok (NULL, ",");
		}
		free (gamedirs);
	}
	// any set gamedirs will be freed up to here
	com_base_searchpaths = com_searchpaths;
}

void
COM_Filesystem_Init_Cvars (void)
{
	fs_sharepath = Cvar_Get ("fs_sharepath", FS_SHAREPATH, CVAR_ROM, NULL,
							 "location of shared (read only) game "
							 "directories");
	fs_userpath = Cvar_Get ("fs_userpath", FS_USERPATH, CVAR_ROM, NULL,
							"location of your game directories");
	fs_basegame = Cvar_Get ("fs_basegame", "id1", CVAR_ROM, NULL,
							"game to use by default");
}

const char *
COM_SkipPath (const char *pathname)
{
	const char *last;

	// char after last / on the line
	if ((last = strrchr (pathname, '/')))
		last++;
	else
		last = pathname;

	return last;
}

void
COM_StripExtension (const char *in, char *out)
{
	while (*in && *in != '.')
		*out++ = *in++;
	*out = 0;
}

char *
COM_FileExtension (char *in)
{
	static char exten[8];
	int         i;

	while (*in && *in != '.')
		in++;
	if (!*in)
		return "";
	in++;
	for (i = 0; i < 7 && *in; i++, in++)
		exten[i] = *in;
	exten[i] = 0;
	return exten;
}

void
COM_DefaultExtension (char *path, char *extension)
{
	char       *src;

	// if path doesn't have a .EXT, append extension
	// (extension should include the .)
	src = path + strlen (path) - 1;

	while (*src != '/' && src != path) {
		if (*src == '.')
			return;						// it has an extension
		src--;
	}

	strncat (path, extension, MAX_OSPATH - strlen (path));
}

int
COM_NextFilename (char *filename, const char *prefix, const char *ext)
{
	char       *digits;
	char        checkname[MAX_OSPATH];
	int         i;

	strncpy (filename, prefix, MAX_OSPATH - 4);
	filename[MAX_OSPATH - 4] = 0;
	digits = filename + strlen (filename);
	strcat (filename, "000");
	strncat (filename, ext, MAX_OSPATH - strlen (filename));

	for (i = 0; i <= 999; i++) {
		digits[0] = i / 100 + '0';
		digits[1] = i / 10 % 10 + '0';
		digits[2] = i % 10 + '0';
		snprintf (checkname, sizeof (checkname), "%s/%s", com_gamedir,
				  filename);
		if (Sys_FileTime (checkname) == -1)
			return 1;					// file doesn't exist
	}
	return 0;
}