/*
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 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 <stdlib.h>
#include <fcntl.h>
#ifdef WIN32
#include <io.h>
#else
#include <unistd.h>
#endif

#include "quakedef.h"

cvar_t registered = {0, "registered","0"};
cvar_t cmdline = {0, "cmdline","0"};

mempool_t *pak_mempool;

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

void COM_InitFilesystem (void);

char com_token[1024];
char com_basedir[MAX_OSPATH];
int com_argc;
const char **com_argv;

// LordHavoc: made commandline 1024 characters instead of 256
#define CMDLINE_LENGTH	1024
char com_cmdline[CMDLINE_LENGTH];

int gamemode;
char *gamename;
char *gamedirname;
char com_modname[MAX_OSPATH];

/*


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.



FIXME:
The file "parms.txt" will be read out of the game directory and appended to the current command line arguments to allow different games to initialize startup parms differently.  This could be used to add a "-sspeed 22050" for the high quality sound edition.  Because they are added at the end, they will not override an explicit setting on the original command line.

*/

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


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

					LIBRARY REPLACEMENT FUNCTIONS

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

int Q_strncasecmp (const char *s1, const 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
	}

	return -1;
}

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

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

					BYTE ORDER FUNCTIONS

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

#if !defined(ENDIAN_LITTLE) && !defined(ENDIAN_BIG)
short   (*BigShort) (short l);
short   (*LittleShort) (short l);
int     (*BigLong) (int l);
int     (*LittleLong) (int l);
float   (*BigFloat) (float l);
float   (*LittleFloat) (float l);
#endif

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

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

	return (b1<<8) + b2;
}

#if !defined(ENDIAN_LITTLE) && !defined(ENDIAN_BIG)
short   ShortNoSwap (short l)
{
	return l;
}
#endif

int    LongSwap (int l)
{
	qbyte    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;
}

#if !defined(ENDIAN_LITTLE) && !defined(ENDIAN_BIG)
int     LongNoSwap (int l)
{
	return l;
}
#endif

float FloatSwap (float f)
{
	union
	{
		float   f;
		qbyte    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;
}

#if !defined(ENDIAN_LITTLE) && !defined(ENDIAN_BIG)
float FloatNoSwap (float f)
{
	return f;
}
#endif

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

			MESSAGE IO FUNCTIONS

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

//
// writing functions
//

void MSG_WriteChar (sizebuf_t *sb, int c)
{
	qbyte    *buf;
	
	buf = SZ_GetSpace (sb, 1);
	buf[0] = c;
}

void MSG_WriteByte (sizebuf_t *sb, int c)
{
	qbyte    *buf;
	
	buf = SZ_GetSpace (sb, 1);
	buf[0] = c;
}

void MSG_WriteShort (sizebuf_t *sb, int c)
{
	qbyte    *buf;

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

void MSG_WriteLong (sizebuf_t *sb, int c)
{
	qbyte    *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, const char *s)
{
	if (!s)
		SZ_Write (sb, "", 1);
	else
		SZ_Write (sb, s, strlen(s)+1);
}

// used by server (always latest dpprotocol)
void MSG_WriteDPCoord (sizebuf_t *sb, float f)
{
	if (f >= 0)
		MSG_WriteShort (sb, (int)(f + 0.5f));
	else
		MSG_WriteShort (sb, (int)(f - 0.5f));
}

void MSG_WritePreciseAngle (sizebuf_t *sb, float f)
{
	if (f >= 0)
		MSG_WriteShort (sb, (int)(f*(65536.0f/360.0f) + 0.5f) & 65535);
	else
		MSG_WriteShort (sb, (int)(f*(65536.0f/360.0f) - 0.5f) & 65535);
}

// LordHavoc: round to nearest value, rather than rounding toward zero, fixes crosshair problem
void MSG_WriteAngle (sizebuf_t *sb, float f)
{
	if (f >= 0)
		MSG_WriteByte (sb, (int)(f*(256.0f/360.0f) + 0.5f) & 255);
	else
		MSG_WriteByte (sb, (int)(f*(256.0f/360.0f) - 0.5f) & 255);
}

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

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

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
	{
		qbyte 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 < (int)sizeof(string)-1);

	string[l] = 0;

	return string;
}

// used by server (always latest dpprotocol)
float MSG_ReadDPCoord (void)
{
	return (signed short) MSG_ReadShort();
}

// used by client
float MSG_ReadCoord (void)
{
	if (dpprotocol == DPPROTOCOL_VERSION2 || dpprotocol == DPPROTOCOL_VERSION3)
		return (signed short) MSG_ReadShort();
	else if (dpprotocol == DPPROTOCOL_VERSION1)
		return MSG_ReadFloat();
	else
		return MSG_ReadShort() * (1.0f/8.0f);
}


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

void SZ_Alloc (sizebuf_t *buf, int startsize, const char *name)
{
	if (startsize < 256)
		startsize = 256;
	buf->mempool = Mem_AllocPool(name);
	buf->data = Mem_Alloc(buf->mempool, startsize);
	buf->maxsize = startsize;
	buf->cursize = 0;
}


void SZ_Free (sizebuf_t *buf)
{
	Mem_FreePool(&buf->mempool);
	buf->data = NULL;
	buf->maxsize = 0;
	buf->cursize = 0;
}

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

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

	if (buf->cursize + length > buf->maxsize)
	{
		if (!buf->allowoverflow)
			Host_Error ("SZ_GetSpace: overflow without allowoverflow set\n");

		if (length > buf->maxsize)
			Host_Error ("SZ_GetSpace: %i is > full buffer size\n", length);

		buf->overflowed = true;
		Con_Printf ("SZ_GetSpace: overflow\n");
		SZ_Clear (buf);
	}

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

	return data;
}

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

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

// byte * cast to keep VC++ happy
	if (buf->data[buf->cursize-1])
		memcpy ((qbyte *)SZ_GetSpace(buf, len),data,len); // no trailing 0
	else
		memcpy ((qbyte *)SZ_GetSpace(buf, len-1)-1,data,len); // write over trailing 0
}

static char *hexchar = "0123456789ABCDEF";
void Com_HexDumpToConsole(const qbyte *data, int size)
{
	int i;
	char text[1024];
	char *cur, *flushpointer;
	cur = text;
	flushpointer = text + 512;
	for (i = 0;i < size;i++)
	{
		if ((i & 15) == 0)
		{
			*cur++ = hexchar[(i >> 12) & 15];
			*cur++ = hexchar[(i >>  8) & 15];
			*cur++ = hexchar[(i >>  4) & 15];
			*cur++ = hexchar[(i >>  0) & 15];
			*cur++ = ':';
			*cur++ = ' ';
		}
		else if ((i & 15) == 15)
			*cur++ = '\n';
		else
			*cur++ = ' ';
		if (i & 1)
		{
			*cur++ = hexchar[(data[i] >> 4) & 15] | 0x80;
			*cur++ = hexchar[(data[i] >> 0) & 15] | 0x80;
		}
		else
		{
			*cur++ = hexchar[(data[i] >> 4) & 15];
			*cur++ = hexchar[(data[i] >> 0) & 15];
		}
		if (cur >= flushpointer)
		{
			*cur++ = 0;
			Con_Printf("%s", text);
			cur = text;
		}
	}
	if ((i & 15) != 0)
		*cur++ = '\n';
	if (cur > text)
	{
		*cur++ = 0;
		Con_Printf("%s", text);
	}
}

void SZ_HexDumpToConsole(const sizebuf_t *buf)
{
	Com_HexDumpToConsole(buf->data, buf->cursize);
}


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


/*
============
COM_StripExtension
============
*/
// LordHavoc: replacement for severely broken COM_StripExtension that was used in original quake.
void COM_StripExtension (const char *in, char *out)
{
	char *last = NULL;
	while (*in)
	{
		if (*in == '.')
			last = out;
		else if (*in == '/' || *in == '\\' || *in == ':')
			last = NULL;
		*out++ = *in++;
	}
	if (last)
		*last = 0;
	else
		*out = 0;
}

/*
============
COM_FileExtension
============
*/
char *COM_FileExtension (const 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 (const char *in, char *out)
{
	const char *slash, *dot, *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;
	}
}


/*
==================
COM_DefaultExtension
==================
*/
void COM_DefaultExtension (char *path, const char *extension)
{
	const 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);
}


/*
==============
COM_ParseToken

Parse a token out of a string
==============
*/
int COM_ParseToken (const char **datapointer)
{
	int c;
	int len;
	const char *data = *datapointer;

	len = 0;
	com_token[0] = 0;

	if (!data)
	{
		*datapointer = NULL;
		return false;
	}

// skip whitespace
skipwhite:
	while ((c = *data) <= ' ')
	{
		if (c == 0)
		{
			// end of file
			*datapointer = NULL;
			return false;
		}
		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;
				*datapointer = data;
				return true;
			}
			com_token[len] = c;
			len++;
		}
	}

// parse single characters
	if (c=='{' || c=='}'|| c==')'|| c=='(' || c=='\'' || c==':')
	{
		com_token[len] = c;
		len++;
		com_token[len] = 0;
		*datapointer = data+1;
		return true;
	}

// parse a regular word
	do
	{
		com_token[len] = c;
		data++;
		len++;
		c = *data;
		if (c=='{' || c=='}'|| c==')'|| c=='(' || c=='\'' || c==':')
			break;
	} while (c>32);

	com_token[len] = 0;
	*datapointer = data;
	return true;
}


/*
================
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 (const char *parm)
{
	int i;

	for (i=1 ; i<com_argc ; i++)
	{
		if (!com_argv[i])
			continue;               // NEXTSTEP sometimes clears appkit vars.
		if (!strcmp (parm,com_argv[i]))
			return i;
	}

	return 0;
}

/*
================
COM_CheckRegistered

Looks for the pop.txt file and verifies it.
Sets the "registered" cvar.
Immediately exits out if an alternate game was attempted to be started without
being registered.
================
*/
void COM_CheckRegistered (void)
{
	Cvar_Set ("cmdline", com_cmdline);

	if (!Sys_FileTime("gfx/pop.lmp"))
	{
		if (com_modified)
			Con_Printf ("Playing shareware version, with modification.\nwarning: most mods require full quake data.\n");
		else
			Con_Printf ("Playing shareware version.\n");
		return;
	}

	Cvar_Set ("registered", "1");
	Con_Printf ("Playing registered version.\n");
}


void COM_Path_f (void);


/*
================
COM_InitArgv
================
*/
void COM_InitArgv (void)
{
	int i, j, n;
	// reconstitute the command line for the cmdline externally visible cvar
	n = 0;
	for (j = 0;(j < MAX_NUM_ARGVS) && (j < com_argc);j++)
	{
		i = 0;
		while ((n < (CMDLINE_LENGTH - 1)) && com_argv[j][i])
			com_cmdline[n++] = com_argv[j][i++];
		if (n < (CMDLINE_LENGTH - 1))
			com_cmdline[n++] = ' ';
		else
			break;
	}
	com_cmdline[n] = 0;
}

void COM_InitGameType (void)
{
	char name[MAX_OSPATH];
	COM_StripExtension(com_argv[0], name);
	COM_ToLowerString(name, name);

	if (strstr(name, "transfusion"))
		gamemode = GAME_TRANSFUSION;
	else if (strstr(name, "nexiuz"))
		gamemode = GAME_NEXIUZ;
	else if (strstr(name, "nehahra"))
		gamemode = GAME_NEHAHRA;
	else if (strstr(name, "hipnotic"))
		gamemode = GAME_HIPNOTIC;
	else if (strstr(name, "rogue"))
		gamemode = GAME_ROGUE;
	else
		gamemode = GAME_NORMAL;

	if (COM_CheckParm ("-transfusion"))
		gamemode = GAME_TRANSFUSION;
	else if (COM_CheckParm ("-nexiuz"))
		gamemode = GAME_NEXIUZ;
	else if (COM_CheckParm ("-nehahra"))
		gamemode = GAME_NEHAHRA;
	else if (COM_CheckParm ("-hipnotic"))
		gamemode = GAME_HIPNOTIC;
	else if (COM_CheckParm ("-rogue"))
		gamemode = GAME_ROGUE;
	else if (COM_CheckParm ("-quake"))
		gamemode = GAME_NORMAL;

	switch(gamemode)
	{
	case GAME_NORMAL:
		gamename = "DarkPlaces-Quake";
		gamedirname = "";
		break;
	case GAME_HIPNOTIC:
		gamename = "Darkplaces-Hipnotic";
		gamedirname = "hipnotic";
		break;
	case GAME_ROGUE:
		gamename = "Darkplaces-Rogue";
		gamedirname = "rogue";
		break;
	case GAME_NEHAHRA:
		gamename = "DarkPlaces-Nehahra";
		gamedirname = "nehahra";
		break;
	case GAME_NEXIUZ:
		gamename = "Nexiuz";
		gamedirname = "data";
		break;
	case GAME_TRANSFUSION:
		gamename = "Transfusion";
		gamedirname = "transfusion";
		break;
	default:
		Sys_Error("COM_InitGameType: unknown gamemode %i\n", gamemode);
		break;
	}
}


extern void Mathlib_Init(void);

/*
================
COM_Init
================
*/
void COM_Init (void)
{
#if !defined(ENDIAN_LITTLE) && !defined(ENDIAN_BIG)
	qbyte swaptest[2] = {1,0};

// set the byte swapping variables in a portable manner
	if ( *(short *)swaptest == 1)
	{
		BigShort = ShortSwap;
		LittleShort = ShortNoSwap;
		BigLong = LongSwap;
		LittleLong = LongNoSwap;
		BigFloat = FloatSwap;
		LittleFloat = FloatNoSwap;
	}
	else
	{
		BigShort = ShortNoSwap;
		LittleShort = ShortSwap;
		BigLong = LongNoSwap;
		LittleLong = LongSwap;
		BigFloat = FloatNoSwap;
		LittleFloat = FloatSwap;
	}
#endif

	pak_mempool = Mem_AllocPool("paks");

	Cvar_RegisterVariable (&registered);
	Cvar_RegisterVariable (&cmdline);
	Cmd_AddCommand ("path", COM_Path_f);

	Mathlib_Init();

	COM_InitFilesystem ();
	COM_CheckRegistered ();

	COM_InitGameType();
}


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

does a varargs printf into a temp buffer, so I don't need to have
varargs versions of all text functions.
FIXME: make this buffer size safe someday
============
*/
char *va(const char *format, ...)
{
	va_list argptr;
	// LordHavoc: now cycles through 8 buffers to avoid problems in most cases
	static char string[8][1024], *s;
	static int stringindex = 0;

	s = string[stringindex];
	stringindex = (stringindex + 1) & 7;
	va_start (argptr, format);
	vsprintf (s, format,argptr);
	va_end (argptr);

	return s;
}


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

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];
	int handle;
	int numfiles;
	packfile_t *files;
	mempool_t *mempool;
	struct pack_s *next;
} 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;

// LordHavoc: was 2048, increased to 65536 and changed info[MAX_PACK_FILES] to a temporary alloc
#define MAX_FILES_IN_PACK       65536

pack_t *packlist = NULL;

#if CACHEENABLE
char com_cachedir[MAX_OSPATH];
#endif
char com_gamedir[MAX_OSPATH];

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

searchpath_t *com_searchpaths;

/*
============
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->pack)
		{
			Con_Printf ("%s (%i files)\n", s->pack->filename, s->pack->numfiles);
		}
		else
			Con_Printf ("%s\n", s->filename);
	}
}

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

LordHavoc: Previously only used for CopyFile, now also used for COM_WriteFile.
============
*/
void    COM_CreatePath (char *path)
{
	char *ofs, save;

	for (ofs = path+1 ; *ofs ; ofs++)
	{
		if (*ofs == '/' || *ofs == '\\')
		{
			// create the directory
			save = *ofs;
			*ofs = 0;
			Sys_mkdir (path);
			*ofs = save;
		}
	}
}


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

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

	sprintf (name, "%s/%s", com_gamedir, filename);

	// LordHavoc: added this
	// create directories up to the file
	COM_CreatePath (name);

	handle = Sys_FileOpenWrite (name);
	if (handle == -1)
	{
		Con_Printf ("COM_WriteFile: failed on %s\n", name);
		return false;
	}

	Con_DPrintf ("COM_WriteFile: %s\n", name);
	Sys_FileWrite (handle, data, len);
	Sys_FileClose (handle);
	return true;
}


/*
===========
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)
{
	int in, out, remaining, count;
	char buf[4096];

	remaining = Sys_FileOpenRead (netpath, &in);
	COM_CreatePath (cachepath);     // create directories up to the cache file
	out = Sys_FileOpenWrite (cachepath);

	while (remaining)
	{
		if (remaining < (int)sizeof(buf))
			count = remaining;
		else
			count = sizeof(buf);
		Sys_FileRead (in, buf, count);
		Sys_FileWrite (out, buf, count);
		remaining -= count;
	}

	Sys_FileClose (in);
	Sys_FileClose (out);
}

/*
===========
COM_OpenRead
===========
*/
QFile * COM_OpenRead (const char *path, int offs, int len, qboolean zip)
{
	int fd = open (path, O_RDONLY);
	unsigned char id[2], 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");
}

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

Finds the file in the search path.
Sets com_filesize and one of handle or file
===========
*/
int COM_FindFile (const char *filename, QFile **file, qboolean quiet, qboolean zip)
{
	searchpath_t *search;
	char netpath[MAX_OSPATH];
#if CACHEENABLE
	char cachepath[MAX_OSPATH];
	int cachetime;
#endif
	pack_t *pak;
	int i, findtime, filenamelen;
	char gzfilename[MAX_OSPATH];

	filenamelen = strlen (filename);
	sprintf (gzfilename, "%s.gz", filename);

	if (!file)
		Sys_Error ("COM_FindFile: file not set");

//
// search through the path, one element at a time
//
	search = com_searchpaths;

	for ( ; 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)
				    || !strcmp (pak->files[i].name, gzfilename))
				{       // found it!
					if (!quiet)
						Sys_Printf ("PackFile: %s : %s\n",pak->filename, pak->files[i].name);
					// open a new file on the pakfile
					*file = COM_OpenRead (pak->filename, pak->files[i].filepos, pak->files[i].filelen, zip);
					return com_filesize;
				}
		}
		else
		{
			sprintf (netpath, "%s/%s",search->filename, filename);

			findtime = Sys_FileTime (netpath);
			if (findtime == -1)
				continue;

#if CACHEENABLE
			// see if the file needs to be updated in the cache
			if (com_cachedir[0])
			{
#if defined(_WIN32)
				if ((strlen(netpath) < 2) || (netpath[1] != ':'))
					sprintf (cachepath,"%s%s", com_cachedir, netpath);
				else
					sprintf (cachepath,"%s%s", com_cachedir, netpath+2);
#else
				sprintf (cachepath,"%s%s", com_cachedir, netpath);
#endif

				cachetime = Sys_FileTime (cachepath);

				if (cachetime < findtime)
					COM_CopyFile (netpath, cachepath);
				strcpy (netpath, cachepath);
			}
#endif
			if (!quiet)
				Sys_Printf ("FindFile: %s\n",netpath);
			*file = COM_OpenRead (netpath, -1, -1, zip);
			return com_filesize;
		}
	}

	if (!quiet)
		Sys_Printf ("FindFile: can't find %s\n", filename);

	*file = NULL;
	com_filesize = -1;
	return -1;
}


/*
===========
COM_FOpenFile

If the requested file is inside a packfile, a new QFile * will be opened
into the file.
===========
*/
int COM_FOpenFile (const char *filename, QFile **file, qboolean quiet, qboolean zip)
{
	return COM_FindFile (filename, file, quiet, zip);
}


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

Filename are reletive to the quake directory.
Always appends a 0 byte.
============
*/
qbyte *loadbuf;
int loadsize;
qbyte *COM_LoadFile (const char *path, qboolean quiet)
{
	QFile *h;
	qbyte *buf;
	char base[1024];
	int len;

	buf = NULL;     // quiet compiler warning
	loadsize = 0;

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

	loadsize = len;

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

	buf = Mem_Alloc(tempmempool, len+1);
	if (!buf)
		Sys_Error ("COM_LoadFile: not enough available memory for %s (size %i)", path, len);

	((qbyte *)buf)[len] = 0;

	Qread (h, buf, len);
	Qclose (h);

	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 (const char *packfile)
{
	dpackheader_t header;
	int i, numpackfiles, packhandle;
	pack_t *pack;
	// LordHavoc: changed from stack array to temporary alloc, allowing huge pack directories
	dpackfile_t *info;

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

	Sys_FileRead (packhandle, (void *)&header, sizeof(header));
	if (memcmp(header.id, "PACK", 4))
		Sys_Error ("%s is not a packfile", packfile);
	header.dirofs = LittleLong (header.dirofs);
	header.dirlen = LittleLong (header.dirlen);

	if (header.dirlen % sizeof(dpackfile_t))
		Sys_Error ("%s has an invalid directory size", packfile);

	numpackfiles = header.dirlen / sizeof(dpackfile_t);

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

	pack = Mem_Alloc(pak_mempool, sizeof (pack_t));
	strcpy (pack->filename, packfile);
	pack->handle = packhandle;
	pack->numfiles = numpackfiles;
	pack->mempool = Mem_AllocPool(packfile);
	pack->files = Mem_Alloc(pack->mempool, numpackfiles * sizeof(packfile_t));
	pack->next = packlist;
	packlist = pack;

	info = Mem_Alloc(tempmempool, sizeof(*info) * numpackfiles);
	Sys_FileSeek (packhandle, header.dirofs);
	Sys_FileRead (packhandle, (void *)info, header.dirlen);

// parse the directory
	for (i = 0;i < numpackfiles;i++)
	{
		strcpy (pack->files[i].name, info[i].name);
		pack->files[i].filepos = LittleLong(info[i].filepos);
		pack->files[i].filelen = LittleLong(info[i].filelen);
	}

	Mem_Free(info);

	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)
{
	stringlist_t *list, *current;
	searchpath_t *search;
	pack_t *pak;
	char pakfile[MAX_OSPATH];

	strcpy (com_gamedir, dir);

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

	// add any paks in the directory
	list = listdirectory(dir);
	for (current = list;current;current = current->next)
	{
		if (matchpattern(current->text, "*.pak", true))
		{
			sprintf (pakfile, "%s/%s", dir, current->text);
			pak = COM_LoadPackFile (pakfile);
			if (pak)
			{
				search = Mem_Alloc(pak_mempool, sizeof(searchpath_t));
				search->pack = pak;
				search->next = com_searchpaths;
				com_searchpaths = search;
			}
			else
				Con_Printf("unable to load pak \"%s\"\n", pakfile);
		}
	}
	freedirectory(list);
}

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

	strcpy(com_basedir, ".");

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

	i = strlen (com_basedir);
	if (i > 0 && (com_basedir[i-1] == '\\' || com_basedir[i-1] == '/'))
		com_basedir[i-1] = 0;

// start up with GAMENAME by default (id1)
	strcpy(com_modname, GAMENAME);
	COM_AddGameDirectory (va("%s/"GAMENAME, com_basedir));
	if (gamedirname[0])
	{
		com_modified = true;
		strcpy(com_modname, gamedirname);
		COM_AddGameDirectory (va("%s/%s", com_basedir, gamedirname));
	}

	// -game <gamedir>
	// Adds basedir/gamedir as an override game
	i = COM_CheckParm ("-game");
	if (i && i < com_argc-1)
	{
		com_modified = true;
		strcpy(com_modname, com_argv[i+1]);
		COM_AddGameDirectory (va("%s/%s", com_basedir, com_argv[i+1]));
	}

	// -path <dir or packfile> [<dir or packfile>] ...
	// Fully specifies the exact search path, overriding the generated one
	i = COM_CheckParm ("-path");
	if (i)
	{
		com_modified = true;
		com_searchpaths = NULL;
		while (++i < com_argc)
		{
			if (!com_argv[i] || com_argv[i][0] == '+' || com_argv[i][0] == '-')
				break;

			search = Mem_Alloc(pak_mempool, sizeof(searchpath_t));
			if ( !strcmp(COM_FileExtension(com_argv[i]), "pak") )
			{
				search->pack = COM_LoadPackFile (com_argv[i]);
				if (!search->pack)
					Sys_Error ("Couldn't load packfile: %s", com_argv[i]);
			}
			else
				strcpy (search->filename, com_argv[i]);
			search->next = com_searchpaths;
			com_searchpaths = search;
		}
	}
}

int COM_FileExists(const char *filename)
{
	searchpath_t *search;
	char netpath[MAX_OSPATH];
	pack_t *pak;
	int i, findtime;

	for (search = com_searchpaths;search;search = search->next)
	{
		if (search->pack)
		{
			pak = search->pack;
			for (i = 0;i < pak->numfiles;i++)
				if (!strcmp (pak->files[i].name, filename))
					return true;
		}
		else
		{
			sprintf (netpath, "%s/%s",search->filename, filename);
			findtime = Sys_FileTime (netpath);
			if (findtime != -1)
				return true;
		}
	}

	return false;
}


//======================================
// LordHavoc: added these because they are useful

void COM_ToLowerString(const char *in, char *out)
{
	while (*in)
	{
		if (*in >= 'A' && *in <= 'Z')
			*out++ = *in++ + 'a' - 'A';
		else
			*out++ = *in++;
	}
}

void COM_ToUpperString(const char *in, char *out)
{
	while (*in)
	{
		if (*in >= 'a' && *in <= 'z')
			*out++ = *in++ + 'A' - 'a';
		else
			*out++ = *in++;
	}
}

int COM_StringBeginsWith(const char *s, const char *match)
{
	for (;*s && *match;s++, match++)
		if (*s != *match)
			return false;
	return true;
}