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

This file is part of Quake III Arena source code.

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

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

You should have received a copy of the GNU General Public License
along with Quake III Arena source code; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
===========================================================================
*/

#include "../../qcommon/q_shared.h"
#include "cmdlib.h"

#include <sys/types.h>
#include <sys/stat.h>


#define PATHSEPERATOR   '/'

char		com_token[1024];
qboolean	com_eof;


char *copystring(const char *s)
{
	char	*b;
	b = malloc(strlen(s)+1);
	strcpy (b, s);
	return b;
}


float Q_FloatTime()
{
	clock_t t = clock();
	return ((float)t / CLOCKS_PER_SEC);
}


void Q_mkdir( const char* path )
{
#ifdef WIN32
	if (_mkdir (path) != -1)
		return;
#else
	if (mkdir (path, 0777) != -1)
		return;
#endif
	if (errno != EEXIST)
		Com_Error( ERR_FATAL, "mkdir %s: %s",path, strerror(errno) );
}


/*
============
FileTime

returns -1 if not present
============
*/
int	FileTime (const char *path)
{
	struct	stat	buf;
	
	if (stat (path,&buf) == -1)
		return -1;
	
	return buf.st_mtime;
}



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

Parse a token out of a string
==============
*/
char *ASM_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)
		{
			com_eof = qtrue;
			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++;
		do
		{
			c = *data++;
			if (c=='\"')
			{
				com_token[len] = 0;
				return data;
			}
			com_token[len] = c;
			len++;
		} while (1);
	}

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

// 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;
	return data;
}


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

						MISC FUNCTIONS

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


/*
================
Q_filelength
================
*/
int Q_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;
}

static FILE* myfopen(const char* filename, const char* mode)
{
	char* p;
	char fn[MAX_OSPATH];

	fn[0] = '\0';
	strncat(fn, filename, sizeof(fn)-1);

	for(p=fn;*p;++p) if(*p == '\\') *p = '/';

	return fopen(fn, mode);
}


FILE* SafeOpenRead( const char* filename )
{
	FILE* f = myfopen( filename, "rb" );

	if (!f)
		Com_Error( ERR_FATAL, "Error opening %s: %s", filename, strerror(errno) );

	return f;
}

FILE* SafeOpenWrite( const char* filename )
{
	FILE* f = myfopen( filename, "wb" );

	if (!f)
		Com_Error( ERR_FATAL, "Error opening %s: %s", filename, strerror(errno) );

	return f;
}


void SafeRead( FILE* f, void* buffer, int count )
{
	if ( fread(buffer, 1, count, f) != (size_t)count )
		Com_Error( ERR_FATAL, "File read failure" );
}


void SafeWrite( FILE* f, const void* buffer, int count )
{
	if ( fwrite(buffer, 1, count, f) != (size_t)count )
		Com_Error( ERR_FATAL, "File write failure" );
}


/*
==============
FileExists
==============
*/
qboolean	FileExists (const char *filename)
{
	FILE	*f;

	f = myfopen (filename, "r");
	if (!f)
		return qfalse;
	fclose (f);
	return qtrue;
}

/*
==============
LoadFile
==============
*/
int    LoadFile( const char *filename, void **bufferptr )
{
	FILE	*f;
	int    length;
	void    *buffer;

	f = SafeOpenRead (filename);
	length = Q_filelength (f);
	buffer = malloc (length+1);
	((char *)buffer)[length] = 0;
	SafeRead (f, buffer, length);
	fclose (f);

	*bufferptr = buffer;
	return length;
}


/*
==============
TryLoadFile

Allows failure
==============
*/
int    TryLoadFile (const char *filename, void **bufferptr)
{
	FILE	*f;
	int    length;
	void    *buffer;

	*bufferptr = NULL;

	f = myfopen (filename, "rb");
	if (!f)
		return -1;
	length = Q_filelength (f);
	buffer = malloc (length+1);
	((char *)buffer)[length] = 0;
	SafeRead (f, buffer, length);
	fclose (f);

	*bufferptr = buffer;
	return length;
}


/*
==============
SaveFile
==============
*/
void    SaveFile (const char *filename, const void *buffer, int count)
{
	FILE	*f;

	f = SafeOpenWrite (filename);
	SafeWrite (f, buffer, count);
	fclose (f);
}


void DefaultPath (char *path, const char *basepath)
{
	char    temp[128];

	if (path[0] == PATHSEPERATOR)
		return;                   // absolute path location
	strcpy (temp,path);
	strcpy (path,basepath);
	strcat (path,temp);
}


void    StripFilename (char *path)
{
	int             length;

	length = strlen(path)-1;
	while (length > 0 && path[length] != PATHSEPERATOR)
		length--;
	path[length] = 0;
}


static int ParseHex( const char* hex )
{
	int num = 0;
	const char* s = hex;

	while (*s)
	{
		num <<= 4;
		if (*s >= '0' && *s <= '9')
			num += *s-'0';
		else if (*s >= 'a' && *s <= 'f')
			num += 10 + *s-'a';
		else if (*s >= 'A' && *s <= 'F')
			num += 10 + *s-'A';
		else
			Com_Error( ERR_FATAL, "Bad hex number: %s", hex );
		s++;
	}

	return num;
}


int ParseNum( const char* s )
{
	if (s[0] == '$')
		return ParseHex( s+1 );
	if (s[0] == '0' && s[1] == 'x')
		return ParseHex( s+2 );
	return atoi( s );
}


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


// FIXME: byte swap?

// this is a 16 bit, non-reflected CRC using the polynomial 0x1021
// and the initial and final xor values shown below...
// in other words, the CCITT standard CRC used by XMODEM

#define CRC_INIT_VALUE	0xffff
#define CRC_XOR_VALUE	0x0000

static const unsigned short crctable[256] =
{
	0x0000,	0x1021,	0x2042,	0x3063,	0x4084,	0x50a5,	0x60c6,	0x70e7,
	0x8108,	0x9129,	0xa14a,	0xb16b,	0xc18c,	0xd1ad,	0xe1ce,	0xf1ef,
	0x1231,	0x0210,	0x3273,	0x2252,	0x52b5,	0x4294,	0x72f7,	0x62d6,
	0x9339,	0x8318,	0xb37b,	0xa35a,	0xd3bd,	0xc39c,	0xf3ff,	0xe3de,
	0x2462,	0x3443,	0x0420,	0x1401,	0x64e6,	0x74c7,	0x44a4,	0x5485,
	0xa56a,	0xb54b,	0x8528,	0x9509,	0xe5ee,	0xf5cf,	0xc5ac,	0xd58d,
	0x3653,	0x2672,	0x1611,	0x0630,	0x76d7,	0x66f6,	0x5695,	0x46b4,
	0xb75b,	0xa77a,	0x9719,	0x8738,	0xf7df,	0xe7fe,	0xd79d,	0xc7bc,
	0x48c4,	0x58e5,	0x6886,	0x78a7,	0x0840,	0x1861,	0x2802,	0x3823,
	0xc9cc,	0xd9ed,	0xe98e,	0xf9af,	0x8948,	0x9969,	0xa90a,	0xb92b,
	0x5af5,	0x4ad4,	0x7ab7,	0x6a96,	0x1a71,	0x0a50,	0x3a33,	0x2a12,
	0xdbfd,	0xcbdc,	0xfbbf,	0xeb9e,	0x9b79,	0x8b58,	0xbb3b,	0xab1a,
	0x6ca6,	0x7c87,	0x4ce4,	0x5cc5,	0x2c22,	0x3c03,	0x0c60,	0x1c41,
	0xedae,	0xfd8f,	0xcdec,	0xddcd,	0xad2a,	0xbd0b,	0x8d68,	0x9d49,
	0x7e97,	0x6eb6,	0x5ed5,	0x4ef4,	0x3e13,	0x2e32,	0x1e51,	0x0e70,
	0xff9f,	0xefbe,	0xdfdd,	0xcffc,	0xbf1b,	0xaf3a,	0x9f59,	0x8f78,
	0x9188,	0x81a9,	0xb1ca,	0xa1eb,	0xd10c,	0xc12d,	0xf14e,	0xe16f,
	0x1080,	0x00a1,	0x30c2,	0x20e3,	0x5004,	0x4025,	0x7046,	0x6067,
	0x83b9,	0x9398,	0xa3fb,	0xb3da,	0xc33d,	0xd31c,	0xe37f,	0xf35e,
	0x02b1,	0x1290,	0x22f3,	0x32d2,	0x4235,	0x5214,	0x6277,	0x7256,
	0xb5ea,	0xa5cb,	0x95a8,	0x8589,	0xf56e,	0xe54f,	0xd52c,	0xc50d,
	0x34e2,	0x24c3,	0x14a0,	0x0481,	0x7466,	0x6447,	0x5424,	0x4405,
	0xa7db,	0xb7fa,	0x8799,	0x97b8,	0xe75f,	0xf77e,	0xc71d,	0xd73c,
	0x26d3,	0x36f2,	0x0691,	0x16b0,	0x6657,	0x7676,	0x4615,	0x5634,
	0xd94c,	0xc96d,	0xf90e,	0xe92f,	0x99c8,	0x89e9,	0xb98a,	0xa9ab,
	0x5844,	0x4865,	0x7806,	0x6827,	0x18c0,	0x08e1,	0x3882,	0x28a3,
	0xcb7d,	0xdb5c,	0xeb3f,	0xfb1e,	0x8bf9,	0x9bd8,	0xabbb,	0xbb9a,
	0x4a75,	0x5a54,	0x6a37,	0x7a16,	0x0af1,	0x1ad0,	0x2ab3,	0x3a92,
	0xfd2e,	0xed0f,	0xdd6c,	0xcd4d,	0xbdaa,	0xad8b,	0x9de8,	0x8dc9,
	0x7c26,	0x6c07,	0x5c64,	0x4c45,	0x3ca2,	0x2c83,	0x1ce0,	0x0cc1,
	0xef1f,	0xff3e,	0xcf5d,	0xdf7c,	0xaf9b,	0xbfba,	0x8fd9,	0x9ff8,
	0x6e17,	0x7e36,	0x4e55,	0x5e74,	0x2e93,	0x3eb2,	0x0ed1,	0x1ef0
};

void CRC_Init(unsigned short *crcvalue)
{
	*crcvalue = CRC_INIT_VALUE;
}

void CRC_ProcessByte(unsigned short *crcvalue, byte data)
{
	*crcvalue = (*crcvalue << 8) ^ crctable[(*crcvalue >> 8) ^ data];
}

unsigned short CRC_Value(unsigned short crcvalue)
{
	return crcvalue ^ CRC_XOR_VALUE;
}

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

/*
============
CreatePath
============
*/
void	CreatePath (const char *path)
{
	const char	*ofs;
	char		c;
	char		dir[1024];

#ifdef _WIN32
	int		olddrive = -1;

	if ( path[1] == ':' )
	{
		olddrive = _getdrive();
		_chdrive( toupper( path[0] ) - 'A' + 1 );
	}
#endif

	if (path[1] == ':')
		path += 2;

	for (ofs = path+1 ; *ofs ; ofs++)
	{
		c = *ofs;
		if (c == '/' || c == '\\')
		{	// create the directory
			memcpy( dir, path, ofs - path );
			dir[ ofs - path ] = 0;
			Q_mkdir( dir );
		}
	}

#ifdef _WIN32
	if ( olddrive != -1 )
	{
		_chdrive( olddrive );
	}
#endif
}


/*
============
QCopyFile

  Used to archive source files
============
*/
void QCopyFile (const char *from, const char *to)
{
	void	*buffer;
	int		length;

	length = LoadFile (from, &buffer);
	CreatePath (to);
	SaveFile (to, buffer, length);
	free (buffer);
}