/*
Copyright (C) 1996-1997 Id Software, Inc.
Portions Copyright (C) 1999,2000  Nelson Rush.
Copyright (C) 1999,2000  contributors of the QuakeForge project
Please see the file "AUTHORS" for a list of contributors

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

*/
// common.c -- misc functions used in client and server

#include <ctype.h>

#ifdef SERVERONLY 
#include "qwsvdef.h"
#else
#include "quakedef.h"
#endif

#define MAX_NUM_ARGVS	50
#define NUM_SAFE_ARGVS	6

usercmd_t nullcmd; // guarenteed to be zero

static char	*largv[MAX_NUM_ARGVS + NUM_SAFE_ARGVS + 1];
static char	*argvdummy = " ";

static char	*safeargvs[NUM_SAFE_ARGVS] =
	{"-stdvid", "-nolan", "-nosound", "-nocdaudio", "-nojoy", "-nomouse"};

qboolean	com_modified;	// set true if using non-id files

qboolean		msg_suppress_1 = 0;

void COM_InitFilesystem (void);
void COM_Path_f (void);


// if a packfile directory differs from this, it is assumed to be hacked
#define	PAK0_COUNT		339
#define	PAK0_CRC		52883

qboolean		standard_quake = true, rogue, hipnotic;

char	gamedirfile[MAX_OSPATH];

extern cvar_t developer;
/*


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

The "base directory" is the path to the directory holding the quake.exe and all game directories.  The sys_* files pass this to host_init in quakeparms_t->basedir.  This can be overridden with the "-basedir" command line parm 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.
	
*/

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


// ClearLink is used for new headnodes
void ClearLink (link_t *l)
{
	l->prev = l->next = l;
}

void RemoveLink (link_t *l)
{
	l->next->prev = l->prev;
	l->prev->next = l->next;
}

void InsertLinkBefore (link_t *l, link_t *before)
{
	l->next = before;
	l->prev = before->prev;
	l->prev->next = l;
	l->next->prev = l;
}
void InsertLinkAfter (link_t *l, link_t *after)
{
	l->next = after->next;
	l->prev = after;
	l->prev->next = l;
	l->next->prev = l;
}

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

					LIBRARY REPLACEMENT FUNCTIONS

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

#if 0
void Q_memset (void *dest, int fill, int count)
{
	int		i;
	
	if ( (((long)dest | count) & 3) == 0)
	{
		count >>= 2;
		fill = fill | (fill<<8) | (fill<<16) | (fill<<24);
		for (i=0 ; i<count ; i++)
			((int *)dest)[i] = fill;
	}
	else
		for (i=0 ; i<count ; i++)
			((byte *)dest)[i] = fill;
}

void Q_memcpy (void *dest, void *src, int count)
{
	int		i;
	
	if (( ( (long)dest | (long)src | count) & 3) == 0 )
	{
		count>>=2;
		for (i=0 ; i<count ; i++)
			((int *)dest)[i] = ((int *)src)[i];
	}
	else
		for (i=0 ; i<count ; i++)
			((byte *)dest)[i] = ((byte *)src)[i];
}

int Q_memcmp (void *m1, void *m2, int count)
{
	while(count)
	{
		count--;
		if (((byte *)m1)[count] != ((byte *)m2)[count])
			return -1;
	}
	return 0;
}

void Q_strcpy (char *dest, char *src)
{
	while (*src)
	{
		*dest++ = *src++;
	}
	*dest++ = 0;
}

void Q_strncpy (char *dest, char *src, int count)
{
	while (*src && count--)
	{
		*dest++ = *src++;
	}
	if (count)
		*dest++ = 0;
}

int Q_strlen (char *str)
{
	int		count;
	
	count = 0;
	while (str[count])
		count++;

	return count;
}

char *Q_strrchr(char *s, char c)
{
    int len = Q_strlen(s);
    s += len;
    while (len--)
        if (*--s == c) return s;
    return 0;
}

void Q_strcat (char *dest, char *src)
{
	dest += Q_strlen(dest);
	Q_strcpy (dest, src);
}

int Q_strcmp (char *s1, char *s2)
{
	while (1)
	{
		if (*s1 != *s2)
			return -1;		// strings not equal	
		if (!*s1)
			return 0;		// strings are equal
		s1++;
		s2++;
	}
	
	return -1;
}

int Q_strncmp (char *s1, char *s2, int count)
{
	while (1)
	{
		if (!count--)
			return 0;
		if (*s1 != *s2)
			return -1;		// strings not equal	
		if (!*s1)
			return 0;		// strings are equal
		s1++;
		s2++;
	}
	
	return -1;
}

int Q_strncasecmp (char *s1, char *s2, int n)
{
	int		c1, c2;
	
	while (1)
	{
		c1 = *s1++;
		c2 = *s2++;

		if (!n--)
			return 0;		// strings are equal until end point
		
		if (c1 != c2)
		{
			if (c1 >= 'a' && c1 <= 'z')
				c1 -= ('a' - 'A');
			if (c2 >= 'a' && c2 <= 'z')
				c2 -= ('a' - 'A');
			if (c1 != c2)
				return -1;		// strings not equal
		}
		if (!c1)
			return 0;		// strings are equal
//		s1++;
//		s2++;
	}
	
	return -1;
}

int Q_strcasecmp (char *s1, char *s2)
{
	return Q_strncasecmp (s1, s2, 99999);
}

#endif

int Q_atoi (char *str)
{
	int		val;
	int		sign;
	int		c;
	
	if (*str == '-')
	{
		sign = -1;
		str++;
	}
	else
		sign = 1;
		
	val = 0;

//
// check for hex
//
	if (str[0] == '0' && (str[1] == 'x' || str[1] == 'X') )
	{
		str += 2;
		while (1)
		{
			c = *str++;
			if (c >= '0' && c <= '9')
				val = (val<<4) + c - '0';
			else if (c >= 'a' && c <= 'f')
				val = (val<<4) + c - 'a' + 10;
			else if (c >= 'A' && c <= 'F')
				val = (val<<4) + c - 'A' + 10;
			else
				return val*sign;
		}
	}
	
//
// check for character
//
	if (str[0] == '\'')
	{
		return sign * str[1];
	}
	
//
// assume decimal
//
	while (1)
	{
		c = *str++;
		if (c <'0' || c > '9')
			return val*sign;
		val = val*10 + c - '0';
	}
	
	return 0;
}


float Q_atof (char *str)
{
	double	val;
	int		sign;
	int		c;
	int		decimal, total;
	
	if (*str == '-')
	{
		sign = -1;
		str++;
	}
	else
		sign = 1;
		
	val = 0;

//
// check for hex
//
	if (str[0] == '0' && (str[1] == 'x' || str[1] == 'X') )
	{
		str += 2;
		while (1)
		{
			c = *str++;
			if (c >= '0' && c <= '9')
				val = (val*16) + c - '0';
			else if (c >= 'a' && c <= 'f')
				val = (val*16) + c - 'a' + 10;
			else if (c >= 'A' && c <= 'F')
				val = (val*16) + c - 'A' + 10;
			else
				return val*sign;
		}
	}
	
//
// check for character
//
	if (str[0] == '\'')
	{
		return sign * str[1];
	}
	
//
// assume decimal
//
	decimal = -1;
	total = 0;
	while (1)
	{
		c = *str++;
		if (c == '.')
		{
			decimal = total;
			continue;
		}
		if (c <'0' || c > '9')
			break;
		val = val*10 + c - '0';
		total++;
	}

	if (decimal == -1)
		return val*sign;
	while (total > decimal)
	{
		val /= 10;
		total--;
	}
	
	return val*sign;
}

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

					BYTE ORDER FUNCTIONS

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

short	(*BigShort) (short l);
short	(*LittleShort) (short l);
int	(*BigLong) (int l);
int	(*LittleLong) (int l);
float	(*BigFloat) (float l);
float	(*LittleFloat) (float l);

short   ShortSwap (short l)
{
	byte    b1,b2;

	b1 = l&255;
	b2 = (l>>8)&255;

	return (b1<<8) + b2;
}

short	ShortNoSwap (short l)
{
	return l;
}

int    LongSwap (int l)
{
	byte    b1,b2,b3,b4;

	b1 = l&255;
	b2 = (l>>8)&255;
	b3 = (l>>16)&255;
	b4 = (l>>24)&255;

	return ((int)b1<<24) + ((int)b2<<16) + ((int)b3<<8) + b4;
}

int	LongNoSwap (int l)
{
	return l;
}

float FloatSwap (float f)
{
	union
	{
		float	f;
		byte	b[4];
	} dat1, dat2;
	
	
	dat1.f = f;
	dat2.b[0] = dat1.b[3];
	dat2.b[1] = dat1.b[2];
	dat2.b[2] = dat1.b[1];
	dat2.b[3] = dat1.b[0];
	return dat2.f;
}

float FloatNoSwap (float f)
{
	return f;
}

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

			MESSAGE IO FUNCTIONS

Handles byte ordering and avoids alignment errors
==============================================================================
*/

//
// writing functions
//

void MSG_WriteChar (sizebuf_t *sb, int c)
{
	byte	*buf;
	
#ifdef PARANOID
	if (c < -128 || c > 127)
		Sys_Error ("MSG_WriteChar: range error");
#endif

	buf = SZ_GetSpace (sb, 1);
	buf[0] = c;
}

void MSG_WriteByte (sizebuf_t *sb, int c)
{
	byte	*buf;
	
#ifdef PARANOID
	if (c < 0 || c > 255)
		Sys_Error ("MSG_WriteByte: range error");
#endif

	buf = SZ_GetSpace (sb, 1);
	buf[0] = c;
}

void MSG_WriteShort (sizebuf_t *sb, int c)
{
	byte	*buf;
	
#ifdef PARANOID
	if (c < ((short)0x8000) || c > (short)0x7fff)
		Sys_Error ("MSG_WriteShort: range error");
#endif

	buf = SZ_GetSpace (sb, 2);
	buf[0] = c&0xff;
	buf[1] = c>>8;
}

void MSG_WriteLong (sizebuf_t *sb, int c)
{
	byte	*buf;
	
	buf = SZ_GetSpace (sb, 4);
	buf[0] = c&0xff;
	buf[1] = (c>>8)&0xff;
	buf[2] = (c>>16)&0xff;
	buf[3] = c>>24;
}

void MSG_WriteFloat (sizebuf_t *sb, float f)
{
	union
	{
		float	f;
		int	l;
	} dat;
	
	
	dat.f = f;
	dat.l = LittleLong (dat.l);
	
	SZ_Write (sb, &dat.l, 4);
}

void MSG_WriteString (sizebuf_t *sb, char *s)
{
	if (!s)
		SZ_Write (sb, "", 1);
	else
		SZ_Write (sb, s, Q_strlen(s)+1);
}

void MSG_WriteCoord (sizebuf_t *sb, float f)
{
	MSG_WriteShort (sb, (int)(f*8));
}

void MSG_WriteAngle (sizebuf_t *sb, float f)
{
	MSG_WriteByte (sb, (int)(f*256/360) & 255);
}

void MSG_WriteAngle16 (sizebuf_t *sb, float f)
{
	MSG_WriteShort (sb, (int)(f*65536/360) & 65535);
}

void MSG_WriteDeltaUsercmd (sizebuf_t *buf, usercmd_t *from, usercmd_t *cmd)
{
	int		bits;

//
// send the movement message
//
	bits = 0;
	if (cmd->angles[0] != from->angles[0])
		bits |= CM_ANGLE1;
	if (cmd->angles[1] != from->angles[1])
		bits |= CM_ANGLE2;
	if (cmd->angles[2] != from->angles[2])
		bits |= CM_ANGLE3;
	if (cmd->forwardmove != from->forwardmove)
		bits |= CM_FORWARD;
	if (cmd->sidemove != from->sidemove)
		bits |= CM_SIDE;
	if (cmd->upmove != from->upmove)
		bits |= CM_UP;
	if (cmd->buttons != from->buttons)
		bits |= CM_BUTTONS;
	if (cmd->impulse != from->impulse)
		bits |= CM_IMPULSE;

    MSG_WriteByte (buf, bits);

	if (bits & CM_ANGLE1)
		MSG_WriteAngle16 (buf, cmd->angles[0]);
	if (bits & CM_ANGLE2)
		MSG_WriteAngle16 (buf, cmd->angles[1]);
	if (bits & CM_ANGLE3)
		MSG_WriteAngle16 (buf, cmd->angles[2]);
	
	if (bits & CM_FORWARD)
		MSG_WriteShort (buf, cmd->forwardmove);
	if (bits & CM_SIDE)
	  	MSG_WriteShort (buf, cmd->sidemove);
	if (bits & CM_UP)
		MSG_WriteShort (buf, cmd->upmove);

 	if (bits & CM_BUTTONS)
	  	MSG_WriteByte (buf, cmd->buttons);
 	if (bits & CM_IMPULSE)
	    MSG_WriteByte (buf, cmd->impulse);
	MSG_WriteByte (buf, cmd->msec);
}


//
// reading functions
//
int			msg_readcount;
qboolean	msg_badread;

void MSG_BeginReading (void)
{
	msg_readcount = 0;
	msg_badread = false;
}

int MSG_GetReadCount(void)
{
	return msg_readcount;
}

// returns -1 and sets msg_badread if no more characters are available
int MSG_ReadChar (void)
{
	int	c;
	
	if (msg_readcount+1 > net_message.cursize)
	{
		msg_badread = true;
		return -1;
	}
		
	c = (signed char)net_message.data[msg_readcount];
	msg_readcount++;
	
	return c;
}

int MSG_ReadByte (void)
{
	int	c;
	
	if (msg_readcount+1 > net_message.cursize)
	{
		msg_badread = true;
		return -1;
	}
		
	c = (unsigned char)net_message.data[msg_readcount];
	msg_readcount++;
	
	return c;
}

int MSG_ReadShort (void)
{
	int	c;
	
	if (msg_readcount+2 > net_message.cursize)
	{
		msg_badread = true;
		return -1;
	}
		
	c = (short)(net_message.data[msg_readcount]
	+ (net_message.data[msg_readcount+1]<<8));
	
	msg_readcount += 2;
	
	return c;
}

int MSG_ReadLong (void)
{
	int	c;
	
	if (msg_readcount+4 > net_message.cursize)
	{
		msg_badread = true;
		return -1;
	}
		
	c = net_message.data[msg_readcount]
	+ (net_message.data[msg_readcount+1]<<8)
	+ (net_message.data[msg_readcount+2]<<16)
	+ (net_message.data[msg_readcount+3]<<24);
	
	msg_readcount += 4;
	
	return c;
}

float MSG_ReadFloat (void)
{
	union
	{
		byte	b[4];
		float	f;
		int	l;
	} dat;
	
	dat.b[0] =	net_message.data[msg_readcount];
	dat.b[1] =	net_message.data[msg_readcount+1];
	dat.b[2] =	net_message.data[msg_readcount+2];
	dat.b[3] =	net_message.data[msg_readcount+3];
	msg_readcount += 4;
	
	dat.l = LittleLong (dat.l);

	return dat.f;	
}

char *MSG_ReadString (void)
{
	static char	string[2048];
	int		l,c;
	
	l = 0;
	do
	{
		c = MSG_ReadChar ();
		if (c == -1 || c == 0)
			break;
		string[l] = c;
		l++;
	} while (l < sizeof(string)-1);
	
	string[l] = 0;
	
	return string;
}

char *MSG_ReadStringLine (void)
{
	static char	string[2048];
	int		l,c;
	
	l = 0;
	do
	{
		c = MSG_ReadChar ();
		if (c == -1 || c == 0 || c == '\n')
			break;
		string[l] = c;
		l++;
	} while (l < sizeof(string)-1);
	
	string[l] = 0;
	
	return string;
}

float MSG_ReadCoord (void)
{
	return MSG_ReadShort() * (1.0/8);
}

float MSG_ReadAngle (void)
{
	return MSG_ReadChar() * (360.0/256);
}

float MSG_ReadAngle16 (void)
{
	return MSG_ReadShort() * (360.0/65536);
}

void MSG_ReadDeltaUsercmd (usercmd_t *from, usercmd_t *move)
{
	int bits;

	memcpy (move, from, sizeof(*move));

	bits = MSG_ReadByte ();
		
// read current angles
	if (bits & CM_ANGLE1)
		move->angles[0] = MSG_ReadAngle16 ();
	if (bits & CM_ANGLE2)
		move->angles[1] = MSG_ReadAngle16 ();
	if (bits & CM_ANGLE3)
		move->angles[2] = MSG_ReadAngle16 ();
		
// read movement
	if (bits & CM_FORWARD)
		move->forwardmove = MSG_ReadShort ();
	if (bits & CM_SIDE)
		move->sidemove = MSG_ReadShort ();
	if (bits & CM_UP)
		move->upmove = MSG_ReadShort ();
	
// read buttons
	if (bits & CM_BUTTONS)
		move->buttons = MSG_ReadByte ();

	if (bits & CM_IMPULSE)
		move->impulse = MSG_ReadByte ();

// read time to run command
	move->msec = MSG_ReadByte ();
}


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

void SZ_Clear (sizebuf_t *buf)
{
	buf->cursize = 0;
	buf->overflowed = false;
}

void *SZ_GetSpace (sizebuf_t *buf, int length)
{
	void	*data;
	
	if (buf->cursize + length > buf->maxsize)
	{
		if (!buf->allowoverflow)
			Sys_Error ("SZ_GetSpace: overflow without allowoverflow set (%d)", buf->maxsize);
		
		if (length > buf->maxsize)
			Sys_Error ("SZ_GetSpace: %i is > full buffer size", length);
			
		Sys_Printf ("SZ_GetSpace: overflow\n");	// because Con_Printf may be redirected
		SZ_Clear (buf); 
		buf->overflowed = true;
	}

	data = buf->data + buf->cursize;
	buf->cursize += length;
	
	return data;
}

void SZ_Write (sizebuf_t *buf, void *data, int length)
{
	Q_memcpy (SZ_GetSpace(buf,length),data,length);		
}

void SZ_Print (sizebuf_t *buf, char *data)
{
	int		len;
	
	len = Q_strlen(data)+1;

	if (!buf->cursize || buf->data[buf->cursize-1])
		Q_memcpy ((byte *)SZ_GetSpace(buf, len),data,len); // no trailing 0
	else
		Q_memcpy ((byte *)SZ_GetSpace(buf, len-1)-1,data,len); // write over trailing 0
}


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


/*
============
COM_SkipPath
============
*/
char *COM_SkipPath (char *pathname)
{
	char	*last;
	
	last = pathname;
	while (*pathname)
	{
		if (*pathname=='/')
			last = pathname+1;
		pathname++;
	}
	return last;
}

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

/*
============
COM_FileExtension
============
*/
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;
}

/*
============
COM_FileBase
============
*/
void COM_FileBase (char *in, char *out)
{
	char *s, *s2;
	
	s = in + strlen(in) - 1;
	
	while (s != in && *s != '.')
		s--;
	
	for (s2 = s ; *s2 && *s2 != '/' ; s2--)
	;
	
	if (s-s2 < 2)
		strcpy (out,"?model?");
	else
	{
		s--;
		strncpy (out,s2+1, s-s2);
		out[s-s2] = 0;
	}
}


/*
==================
COM_DefaultExtension
==================
*/
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--;
	}

	strcat (path, extension);
}

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

char		com_token[1024];
int		com_argc;
char	**com_argv;


/*
==============
COM_Parse

Parse a token out of a string
==============
*/
char *COM_Parse (char *data)
{
	int		c;
	int		len;
	
	len = 0;
	com_token[0] = 0;
	
	if (!data)
		return NULL;
		
// skip whitespace
skipwhite:
	while ( (c = *data) <= ' ')
	{
		if (c == 0)
			return NULL;			// end of file;
		data++;
	}
	
// skip // comments
	if (c=='/' && data[1] == '/')
	{
		while (*data && *data != '\n')
			data++;
		goto skipwhite;
	}
	

// handle quoted strings specially
	if (c == '\"')
	{
		data++;
		while (1)
		{
			c = *data++;
			if (c=='\"' || !c)
			{
				com_token[len] = 0;
				return data;
			}
			com_token[len] = c;
			len++;
		}
	}

// parse a regular word
	do
	{
		com_token[len] = c;
		data++;
		len++;
		c = *data;
	} while (c>32);
	
	com_token[len] = 0;
	return data;
}


/*
================
COM_CheckParm

Returns the position (1 to argc-1) in the program's argument list
where the given parameter apears, or 0 if not present
================
*/
int COM_CheckParm (char *parm)
{
	int		i;
	
	for (i=1 ; i<com_argc ; i++)
	{
		if (!com_argv[i])
			continue;		// NEXTSTEP sometimes clears appkit vars.
		if (!Q_strcmp (parm,com_argv[i]))
			return i;
	}
		
	return 0;
}

/*
================
COM_InitArgv
================
*/
void COM_InitArgv (int argc, char **argv)
{
	qboolean	safe;
	int			i;

	safe = false;

	for (com_argc=0 ; (com_argc<MAX_NUM_ARGVS) && (com_argc < argc) ;
		 com_argc++)
	{
		largv[com_argc] = argv[com_argc];
		if (!Q_strcmp ("-safe", argv[com_argc]))
			safe = true;
	}

	if (safe)
	{
	// force all the safe-mode switches. Note that we reserved extra space in
	// case we need to add these, so we don't need an overflow check
		for (i=0 ; i<NUM_SAFE_ARGVS ; i++)
		{
			largv[com_argc] = safeargvs[i];
			com_argc++;
		}
	}

	largv[com_argc] = argvdummy;
	com_argv = largv;
}

/*
================
COM_AddParm

Adds the given string at the end of the current argument list
================
*/
void COM_AddParm (char *parm)
{
	largv[com_argc++] = parm;
}


/*
================
COM_Init
================
*/
void COM_Init (void)
{
#ifdef WORDS_BIGENDIAN
	BigShort = ShortNoSwap;
	LittleShort = ShortSwap;
	BigLong = LongNoSwap;
	LittleLong = LongSwap;
	BigFloat = FloatNoSwap;
	LittleFloat = FloatSwap;
#else
	BigShort = ShortSwap;
	LittleShort = ShortNoSwap;
	BigLong = LongSwap;
	LittleLong = LongNoSwap;
	BigFloat = FloatSwap;
	LittleFloat = FloatNoSwap;
#endif

	Cmd_AddCommand ("path", COM_Path_f);

	COM_InitFilesystem ();
	register_check ();
}


/*
============
va

does a varargs printf into a temp buffer, so I don't need to have
varargs versions of all text functions.
============
*/
char	*va(char *format, ...)
{
	va_list		argptr;
	static char		string[1024];
	
	va_start (argptr, format);
	vsnprintf (string, sizeof(string), format, argptr);
	va_end (argptr);

	return string;	
}


/// just for debugging
int	memsearch (byte *start, int count, int search)
{
	int		i;
	
	for (i=0 ; i<count ; i++)
		if (start[i] == search)
			return i;
	return -1;
}

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

QUAKE FILESYSTEM

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

int	com_filesize;


//
// in memory
//

typedef struct
{
	char	name[MAX_QPATH];
	int		filepos, filelen;
} packfile_t;

typedef struct pack_s
{
	char	filename[MAX_OSPATH];
	FILE	*handle;
	int		numfiles;
	packfile_t	*files;
} pack_t;

//
// 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];
char	com_basedir[MAX_OSPATH];

typedef struct searchpath_s
{
	char	filename[MAX_OSPATH];
	pack_t	*pack;		// only one of filename / pack will be used
	struct searchpath_s *next;
} searchpath_t;

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

/*
================
COM_filelength
================
*/
int COM_filelength (FILE *f)
{
	int		pos;
	int		end;

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

	return end;
}

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

	f = fopen(path, "rb");
	if (!f)
	{
		*hndl = NULL;
		return -1;
	}
	*hndl = f;
	
	return COM_filelength(f);
}

/*
============
COM_Path_f

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

/*
============
COM_WriteFile

The filename will be prefixed by the current game directory
============
*/
void COM_WriteFile (char *filename, void *data, int len)
{
	FILE	*f;
	char	name[MAX_OSPATH];
	
	snprintf(name, sizeof(name), "%s/%s", com_gamedir, filename);
	
	f = fopen (name, "wb");
	if (!f) {
		Sys_mkdir(com_gamedir);
		f = fopen (name, "wb");
		if (!f)
			Sys_Error ("Error opening %s", filename);
	}
	
	Sys_Printf ("COM_WriteFile: %s\n", name);
	fwrite (data, 1, len, f);
	fclose (f);
}


/*
============
COM_CreatePath

Only used for CopyFile and download
============
*/
void	COM_CreatePath (char *path)
{
	char	*ofs;
	
	for (ofs = path+1 ; *ofs ; ofs++)
	{
		if (*ofs == '/')
		{	// create the directory
			*ofs = 0;
			Sys_mkdir (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)
{
	FILE	*in, *out;
	int		remaining, count;
	char	buf[4096];
	
	remaining = COM_FileOpenRead (netpath, &in);		
	COM_CreatePath (cachepath);	// create directories up to the cache file
	out = fopen(cachepath, "wb");
	if (!out)
		Sys_Error ("Error opening %s", cachepath);
	
	while (remaining)
	{
		if (remaining < sizeof(buf))
			count = remaining;
		else
			count = sizeof(buf);
		fread (buf, 1, count, in);
		fwrite (buf, 1, count, out);
		remaining -= count;
	}

	fclose (in);
	fclose (out);
}

/*
===========
COM_FindFile

Finds the file in the search path.
Sets com_filesize and one of handle or file
===========
*/
int file_from_pak; // global indicating file came from pack file ZOID

int COM_FOpenFile (char *filename, FILE **file)
{
	searchpath_t	*search;
	char		netpath[MAX_OSPATH];
	pack_t		*pak;
	int			i;
	int			findtime;

	file_from_pak = 0;
		
//
// 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)
		{
		// look through all the pak file elements
			pak = search->pack;
			for (i=0 ; i<pak->numfiles ; i++)
				if (!strcmp (pak->files[i].name, filename))
				{	// found it!
					if(developer.value)
						Sys_Printf ("PackFile: %s : %s\n",pak->filename, filename);
				// open a new file on the pakfile
					*file = fopen (pak->filename, "rb");
					if (!*file)
						Sys_Error ("Couldn't reopen %s", pak->filename);	
					fseek (*file, pak->files[i].filepos, SEEK_SET);
					com_filesize = pak->files[i].filelen;
					file_from_pak = 1;
					return com_filesize;
				}
		}
		else
		{		
	// check a file in the directory tree
			snprintf(netpath, sizeof(netpath), "%s/%s",search->filename, filename);
			
			findtime = Sys_FileTime (netpath);
			if (findtime == -1)
				continue;
				
			if(developer.value)
				Sys_Printf ("FindFile: %s\n",netpath);

			*file = fopen (netpath, "rb");
			return COM_filelength (*file);
		}
		
	}
	
	Sys_Printf ("FindFile: can't find %s\n", filename);
	
	*file = NULL;
	com_filesize = -1;
	return -1;
}

/*
============
COM_LoadFile

Filename are reletive to the quake directory.
Allways appends a 0 byte to the loaded data.
============
*/
cache_user_t *loadcache;
byte	*loadbuf;
int		loadsize;
byte *COM_LoadFile (char *path, int usehunk)
{
	FILE	*h;
	byte	*buf;
	char	base[32];
	int		len;

	buf = NULL;	// quiet compiler warning

// 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 = Z_Malloc (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);
		
	((byte *)buf)[len] = 0;
#ifndef SERVERONLY
	Draw_BeginDisc ();
#endif
	fread (buf, 1, len, h);
	fclose (h);
#ifndef SERVERONLY
	Draw_EndDisc ();
#endif

	return buf;
}

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

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

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

// uses temp hunk if larger than bufsize
byte *COM_LoadStackFile (char *path, void *buffer, int bufsize)
{
	byte	*buf;
	
	loadbuf = (byte *)buffer;
	loadsize = bufsize;
	buf = COM_LoadFile (path, 4);
	
	return buf;
}

/*
=================
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;
	FILE			*packhandle;
	dpackfile_t		info[MAX_FILES_IN_PACK];
	unsigned short		crc;

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

	fread (&header, 1, sizeof(header), packhandle);
	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);

	if (numpackfiles != PAK0_COUNT)
		com_modified = true;	// not the original file

	newfiles = Z_Malloc (numpackfiles * sizeof(packfile_t));

	fseek (packhandle, header.dirofs, SEEK_SET);
	fread (info, 1, header.dirlen, packhandle);

// crc the directory to check for modifications
	crc = CRC_Block((byte *)info, header.dirlen);

//	CRC_Init (&crc);
//	for (i=0 ; i<header.dirlen ; i++)
//		CRC_ProcessByte (&crc, ((byte *)info)[i]);
	if (crc != PAK0_CRC)
		com_modified = true;

// 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);
	}

	pack = Z_Malloc (sizeof (pack_t));
	strcpy (pack->filename, packfile);
	pack->handle = packhandle;
	pack->numfiles = numpackfiles;
	pack->files = newfiles;
	
	Con_Printf ("Added packfile %s (%i files)\n", packfile, numpackfiles);
	return pack;
}


/*
================
COM_AddGameDirectory

Sets com_gamedir, adds the directory to the head of the path,
then loads and adds pak1.pak pak2.pak ... 
================
*/
void COM_AddGameDirectory (char *dir)
{
	int				i;
	searchpath_t	*search;
	pack_t			*pak;
	char			pakfile[MAX_OSPATH];
	char			*p;

	if ((p = strrchr(dir, '/')) != NULL)
		strcpy(gamedirfile, ++p);
	else
		strcpy(gamedirfile, p);
	strcpy (com_gamedir, dir);

//
// add the directory to the search path
//
	search = Hunk_Alloc (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, ...
//
	for (i=0 ; ; i++)
	{
		snprintf(pakfile, sizeof(pakfile), "%s/pak%i.pak", dir, i);
		pak = COM_LoadPackFile (pakfile);
		if (!pak)
			break;
		search = Hunk_Alloc (sizeof(searchpath_t));
		search->pack = pak;
		search->next = com_searchpaths;
		com_searchpaths = search;		
	}

}

/*
================
COM_Gamedir

Sets the gamedir and path to a different directory.
================
*/
void COM_Gamedir (char *dir)
{
	searchpath_t	*search, *next;
	int				i;
	pack_t			*pak;
	char			pakfile[MAX_OSPATH];

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

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

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

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

	if (!strcmp(dir,"id1") || !strcmp(dir, "qw"))
		return;

	snprintf(com_gamedir, sizeof(com_gamedir), "%s/%s", com_basedir, dir);

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

	//
	// add any pak files in the format pak0.pak pak1.pak, ...
	//
	for (i=0 ; ; i++)
	{
		snprintf(pakfile, sizeof(pakfile), "%s/pak%i.pak", com_gamedir, i);
		pak = COM_LoadPackFile (pakfile);
		if (!pak)
			break;
		search = Z_Malloc (sizeof(searchpath_t));
		search->pack = pak;
		search->next = com_searchpaths;
		com_searchpaths = search;		
	}
}

/*
================
COM_InitFilesystem
================
*/
void COM_InitFilesystem (void)
{
	int		i;

//
// -basedir <path>
// Overrides the system supplied base directory (under id1)
//
	i = COM_CheckParm ("-basedir");
	if (i && i < com_argc-1)
		strcpy (com_basedir, com_argv[i+1]);
	else
		strcpy (com_basedir, host_parms.basedir);

//
// start up with id1 by default
//
	COM_AddGameDirectory (va("%s/id1", com_basedir) );
	COM_AddGameDirectory (va("%s/qw", com_basedir) );

	// any set gamedirs will be freed up to here
	com_base_searchpaths = com_searchpaths;
}



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

  INFO STRINGS

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

/*
===============
Info_ValueForKey

Searches the string for the given
key and returns the associated value, or an empty string.
===============
*/
char *Info_ValueForKey (char *s, char *key)
{
	char	pkey[512];
	static	char value[4][512];	// use two buffers so compares
								// work without stomping on each other
	static	int	valueindex;
	char	*o;
	
	valueindex = (valueindex + 1) % 4;
	if (*s == '\\')
		s++;
	while (1)
	{
		o = pkey;
		while (*s != '\\')
		{
			if (!*s)
				return "";
			*o++ = *s++;
		}
		*o = 0;
		s++;

		o = value[valueindex];

		while (*s != '\\' && *s)
		{
			if (!*s)
				return "";
			*o++ = *s++;
		}
		*o = 0;

		if (!strcmp (key, pkey) )
			return value[valueindex];

		if (!*s)
			return "";
		s++;
	}
}

void Info_RemoveKey (char *s, char *key)
{
	char	*start;
	char	pkey[512];
	char	value[512];
	char	*o;

	if (strstr (key, "\\"))
	{
		Con_Printf ("Can't use a key with a \\\n");
		return;
	}

	while (1)
	{
		start = s;
		if (*s == '\\')
			s++;
		o = pkey;
		while (*s != '\\')
		{
			if (!*s)
				return;
			*o++ = *s++;
		}
		*o = 0;
		s++;

		o = value;
		while (*s != '\\' && *s)
		{
			if (!*s)
				return;
			*o++ = *s++;
		}
		*o = 0;

		if (!strcmp (key, pkey) )
		{
			strcpy (start, s);	// remove this part
			return;
		}

		if (!*s)
			return;
	}

}

void Info_RemovePrefixedKeys (char *start, char prefix)
{
	char	*s;
	char	pkey[512];
	char	value[512];
	char	*o;

	s = start;

	while (1)
	{
		if (*s == '\\')
			s++;
		o = pkey;
		while (*s != '\\')
		{
			if (!*s)
				return;
			*o++ = *s++;
		}
		*o = 0;
		s++;

		o = value;
		while (*s != '\\' && *s)
		{
			if (!*s)
				return;
			*o++ = *s++;
		}
		*o = 0;

		if (pkey[0] == prefix)
		{
			Info_RemoveKey (start, pkey);
			s = start;
		}

		if (!*s)
			return;
	}

}


void Info_SetValueForStarKey (char *s, char *key, char *value, int maxsize)
{
	char	new[1024], *v;
	int		c;
#ifdef SERVERONLY
	extern cvar_t sv_highchars;
#endif

	if (strstr (key, "\\") || strstr (value, "\\") )
	{
		Con_Printf ("Can't use keys or values with a \\\n");
		return;
	}

	if (strstr (key, "\"") || strstr (value, "\"") )
	{
		Con_Printf ("Can't use keys or values with a \"\n");
		return;
	}

	if (strlen(key) > 63 || strlen(value) > 63)
	{
		Con_Printf ("Keys and values must be < 64 characters.\n");
		return;
	}

	// this next line is kinda trippy
	if (*(v = Info_ValueForKey(s, key))) {
		// key exists, make sure we have enough room for new value,
		// if we don't, don't change it!
		if (strlen(value) - strlen(v) + strlen(s) > maxsize) {
			Con_Printf ("Info 1 string length exceeded\n");
			return;
		}
	}
	Info_RemoveKey (s, key);
	if (!value || !strlen(value))
		return;

	snprintf(new, sizeof(new), "\\%s\\%s", key, value);

	if ((int)(strlen(new) + strlen(s)) > maxsize)
	{
		Con_Printf ("Info 2 string length exceeded\n");
		return;
	}

	// only copy ascii values
	s += strlen(s);
	v = new;
	while (*v)
	{
		c = (unsigned char)*v++;
#ifndef SERVERONLY
		// client only allows highbits on name
		if (stricmp(key, "name") != 0) {
			c &= 127;
			if (c < 32 || c > 127)
				continue;
			// auto lowercase team
			if (stricmp(key, "team") == 0)
				c = tolower(c);
		}
#else
		if (!sv_highchars.value) {
			c &= 127;
			if (c < 32 || c > 127)
				continue;
		}
#endif
//		c &= 127;		// strip high bits
		if (c > 13) // && c < 127)
			*s++ = c;
	}
	*s = 0;
}

void Info_SetValueForKey (char *s, char *key, char *value, int maxsize)
{
	if (key[0] == '*')
	{
		Con_Printf ("Can't set * keys\n");
		return;
	}

	Info_SetValueForStarKey (s, key, value, maxsize);
}

void Info_Print (char *s)
{
	char	key[512];
	char	value[512];
	char	*o;
	int		l;

	if (*s == '\\')
		s++;
	while (*s)
	{
		o = key;
		while (*s && *s != '\\')
			*o++ = *s++;

		l = o - key;
		if (l < 20)
		{
			memset (o, ' ', 20-l);
			key[20] = 0;
		}
		else
			*o = 0;
		Con_Printf ("%s", key);

		if (!*s)
		{
			Con_Printf ("MISSING VALUE\n");
			return;
		}

		o = value;
		s++;
		while (*s && *s != '\\')
			*o++ = *s++;
		*o = 0;

		if (*s)
			s++;
		Con_Printf ("%s\n", value);
	}
}

static byte chktbl[1024 + 4] = {
0x78,0xd2,0x94,0xe3,0x41,0xec,0xd6,0xd5,0xcb,0xfc,0xdb,0x8a,0x4b,0xcc,0x85,0x01,
0x23,0xd2,0xe5,0xf2,0x29,0xa7,0x45,0x94,0x4a,0x62,0xe3,0xa5,0x6f,0x3f,0xe1,0x7a,
0x64,0xed,0x5c,0x99,0x29,0x87,0xa8,0x78,0x59,0x0d,0xaa,0x0f,0x25,0x0a,0x5c,0x58,
0xfb,0x00,0xa7,0xa8,0x8a,0x1d,0x86,0x80,0xc5,0x1f,0xd2,0x28,0x69,0x71,0x58,0xc3,
0x51,0x90,0xe1,0xf8,0x6a,0xf3,0x8f,0xb0,0x68,0xdf,0x95,0x40,0x5c,0xe4,0x24,0x6b,
0x29,0x19,0x71,0x3f,0x42,0x63,0x6c,0x48,0xe7,0xad,0xa8,0x4b,0x91,0x8f,0x42,0x36,
0x34,0xe7,0x32,0x55,0x59,0x2d,0x36,0x38,0x38,0x59,0x9b,0x08,0x16,0x4d,0x8d,0xf8,
0x0a,0xa4,0x52,0x01,0xbb,0x52,0xa9,0xfd,0x40,0x18,0x97,0x37,0xff,0xc9,0x82,0x27,
0xb2,0x64,0x60,0xce,0x00,0xd9,0x04,0xf0,0x9e,0x99,0xbd,0xce,0x8f,0x90,0x4a,0xdd,
0xe1,0xec,0x19,0x14,0xb1,0xfb,0xca,0x1e,0x98,0x0f,0xd4,0xcb,0x80,0xd6,0x05,0x63,
0xfd,0xa0,0x74,0xa6,0x86,0xf6,0x19,0x98,0x76,0x27,0x68,0xf7,0xe9,0x09,0x9a,0xf2,
0x2e,0x42,0xe1,0xbe,0x64,0x48,0x2a,0x74,0x30,0xbb,0x07,0xcc,0x1f,0xd4,0x91,0x9d,
0xac,0x55,0x53,0x25,0xb9,0x64,0xf7,0x58,0x4c,0x34,0x16,0xbc,0xf6,0x12,0x2b,0x65,
0x68,0x25,0x2e,0x29,0x1f,0xbb,0xb9,0xee,0x6d,0x0c,0x8e,0xbb,0xd2,0x5f,0x1d,0x8f,
0xc1,0x39,0xf9,0x8d,0xc0,0x39,0x75,0xcf,0x25,0x17,0xbe,0x96,0xaf,0x98,0x9f,0x5f,
0x65,0x15,0xc4,0x62,0xf8,0x55,0xfc,0xab,0x54,0xcf,0xdc,0x14,0x06,0xc8,0xfc,0x42,
0xd3,0xf0,0xad,0x10,0x08,0xcd,0xd4,0x11,0xbb,0xca,0x67,0xc6,0x48,0x5f,0x9d,0x59,
0xe3,0xe8,0x53,0x67,0x27,0x2d,0x34,0x9e,0x9e,0x24,0x29,0xdb,0x69,0x99,0x86,0xf9,
0x20,0xb5,0xbb,0x5b,0xb0,0xf9,0xc3,0x67,0xad,0x1c,0x9c,0xf7,0xcc,0xef,0xce,0x69,
0xe0,0x26,0x8f,0x79,0xbd,0xca,0x10,0x17,0xda,0xa9,0x88,0x57,0x9b,0x15,0x24,0xba,
0x84,0xd0,0xeb,0x4d,0x14,0xf5,0xfc,0xe6,0x51,0x6c,0x6f,0x64,0x6b,0x73,0xec,0x85,
0xf1,0x6f,0xe1,0x67,0x25,0x10,0x77,0x32,0x9e,0x85,0x6e,0x69,0xb1,0x83,0x00,0xe4,
0x13,0xa4,0x45,0x34,0x3b,0x40,0xff,0x41,0x82,0x89,0x79,0x57,0xfd,0xd2,0x8e,0xe8,
0xfc,0x1d,0x19,0x21,0x12,0x00,0xd7,0x66,0xe5,0xc7,0x10,0x1d,0xcb,0x75,0xe8,0xfa,
0xb6,0xee,0x7b,0x2f,0x1a,0x25,0x24,0xb9,0x9f,0x1d,0x78,0xfb,0x84,0xd0,0x17,0x05,
0x71,0xb3,0xc8,0x18,0xff,0x62,0xee,0xed,0x53,0xab,0x78,0xd3,0x65,0x2d,0xbb,0xc7,
0xc1,0xe7,0x70,0xa2,0x43,0x2c,0x7c,0xc7,0x16,0x04,0xd2,0x45,0xd5,0x6b,0x6c,0x7a,
0x5e,0xa1,0x50,0x2e,0x31,0x5b,0xcc,0xe8,0x65,0x8b,0x16,0x85,0xbf,0x82,0x83,0xfb,
0xde,0x9f,0x36,0x48,0x32,0x79,0xd6,0x9b,0xfb,0x52,0x45,0xbf,0x43,0xf7,0x0b,0x0b,
0x19,0x19,0x31,0xc3,0x85,0xec,0x1d,0x8c,0x20,0xf0,0x3a,0xfa,0x80,0x4d,0x2c,0x7d,
0xac,0x60,0x09,0xc0,0x40,0xee,0xb9,0xeb,0x13,0x5b,0xe8,0x2b,0xb1,0x20,0xf0,0xce,
0x4c,0xbd,0xc6,0x04,0x86,0x70,0xc6,0x33,0xc3,0x15,0x0f,0x65,0x19,0xfd,0xc2,0xd3,

// map checksum goes here
0x00,0x00,0x00,0x00
};

#if 0
static byte chkbuf[16 + 60 + 4];

static unsigned last_mapchecksum = 0;

/*
====================
COM_BlockSequenceCheckByte

For proxy protecting
====================
*/
byte	COM_BlockSequenceCheckByte (byte *base, int length, int sequence, unsigned mapchecksum)
{
	int		checksum;
	byte	*p;

	if (last_mapchecksum != mapchecksum) {
		last_mapchecksum = mapchecksum;
		chktbl[1024] = (mapchecksum & 0xff000000) >> 24;
		chktbl[1025] = (mapchecksum & 0x00ff0000) >> 16;
		chktbl[1026] = (mapchecksum & 0x0000ff00) >> 8;
		chktbl[1027] = (mapchecksum & 0x000000ff);

		Com_BlockFullChecksum (chktbl, sizeof(chktbl), chkbuf);
	}

	p = chktbl + (sequence % (sizeof(chktbl) - 8));

	if (length > 60)
		length = 60;
	memcpy (chkbuf + 16, base, length);

	length += 16;

	chkbuf[length] = (sequence & 0xff) ^ p[0];
	chkbuf[length+1] = p[1];
	chkbuf[length+2] = ((sequence>>8) & 0xff) ^ p[2];
	chkbuf[length+3] = p[3];

	length += 4;

	checksum = LittleLong(Com_BlockChecksum (chkbuf, length));

	checksum &= 0xff;

	return checksum;
}
#endif

/*
====================
COM_BlockSequenceCRCByte

For proxy protecting
====================
*/
byte	COM_BlockSequenceCRCByte (byte *base, int length, int sequence)
{
	unsigned short crc;
	byte	*p;
	byte chkb[60 + 4];

	p = chktbl + (sequence % (sizeof(chktbl) - 8));

	if (length > 60)
		length = 60;
	memcpy (chkb, base, length);

	chkb[length] = (sequence & 0xff) ^ p[0];
	chkb[length+1] = p[1];
	chkb[length+2] = ((sequence>>8) & 0xff) ^ p[2];
	chkb[length+3] = p[3];

	length += 4;

	crc = CRC_Block(chkb, length);

	crc &= 0xff;

	return crc;
}