msg.c

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

This file is part of Quake III Arena source code.

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

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

You should have received a copy of the GNU General Public License
along with Foobar; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
===========================================================================
*/
#include "../game/q_shared.h"
#include "qcommon.h"

static huffman_t		msgHuff;

static qboolean			msgInit = qfalse;

int pcount[256];

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

			MESSAGE IO FUNCTIONS

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

int oldsize = 0;

void MSG_initHuffman();

void MSG_Init( msg_t *buf, byte *data, int length ) {
	if (!msgInit) {
		MSG_initHuffman();
	}
	Com_Memset (buf, 0, sizeof(*buf));
	buf->data = data;
	buf->maxsize = length;
}

void MSG_InitOOB( msg_t *buf, byte *data, int length ) {
	if (!msgInit) {
		MSG_initHuffman();
	}
	Com_Memset (buf, 0, sizeof(*buf));
	buf->data = data;
	buf->maxsize = length;
	buf->oob = qtrue;
}

void MSG_Clear( msg_t *buf ) {
	buf->cursize = 0;
	buf->overflowed = qfalse;
	buf->bit = 0;					//<- in bits
}


void MSG_Bitstream( msg_t *buf ) {
	buf->oob = qfalse;
}

void MSG_BeginReading( msg_t *msg ) {
	msg->readcount = 0;
	msg->bit = 0;
	msg->oob = qfalse;
}

void MSG_BeginReadingOOB( msg_t *msg ) {
	msg->readcount = 0;
	msg->bit = 0;
	msg->oob = qtrue;
}

void MSG_Copy(msg_t *buf, byte *data, int length, msg_t *src)
{
	if (length<src->cursize) {
		Com_Error( ERR_DROP, "MSG_Copy: can't copy into a smaller msg_t buffer");
	}
	Com_Memcpy(buf, src, sizeof(msg_t));
	buf->data = data;
	Com_Memcpy(buf->data, src->data, src->cursize);
}

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

bit functions
  
=============================================================================
*/

int	overflows;

// negative bit values include signs
void MSG_WriteBits( msg_t *msg, int value, int bits ) {
	int	i;
//	FILE*	fp;

	oldsize += bits;

	// this isn't an exact overflow check, but close enough
	if ( msg->maxsize - msg->cursize < 4 ) {
		msg->overflowed = qtrue;
		return;
	}

	if ( bits == 0 || bits < -31 || bits > 32 ) {
		Com_Error( ERR_DROP, "MSG_WriteBits: bad bits %i", bits );
	}

	// check for overflows
	if ( bits != 32 ) {
		if ( bits > 0 ) {
			if ( value > ( ( 1 << bits ) - 1 ) || value < 0 ) {
				overflows++;
			}
		} else {
			int	r;

			r = 1 << (bits-1);

			if ( value >  r - 1 || value < -r ) {
				overflows++;
			}
		}
	}
	if ( bits < 0 ) {
		bits = -bits;
	}
	if (msg->oob) {
		if (bits==8) {
			msg->data[msg->cursize] = value;
			msg->cursize += 1;
			msg->bit += 8;
		} else if (bits==16) {
			unsigned short *sp = (unsigned short *)&msg->data[msg->cursize];
			*sp = LittleShort(value);
			msg->cursize += 2;
			msg->bit += 16;
		} else if (bits==32) {
			unsigned int *ip = (unsigned int *)&msg->data[msg->cursize];
			*ip = LittleLong(value);
			msg->cursize += 4;
			msg->bit += 8;
		} else {
			Com_Error(ERR_DROP, "can't read %d bits\n", bits);
		}
	} else {
//		fp = fopen("c:\\netchan.bin", "a");
		value &= (0xffffffff>>(32-bits));
		if (bits&7) {
			int nbits;
			nbits = bits&7;
			for(i=0;i<nbits;i++) {
				Huff_putBit((value&1), msg->data, &msg->bit);
				value = (value>>1);
			}
			bits = bits - nbits;
		}
		if (bits) {
			for(i=0;i<bits;i+=8) {
//				fwrite(bp, 1, 1, fp);
				Huff_offsetTransmit (&msgHuff.compressor, (value&0xff), msg->data, &msg->bit);
				value = (value>>8);
			}
		}
		msg->cursize = (msg->bit>>3)+1;
//		fclose(fp);
	}
}

int MSG_ReadBits( msg_t *msg, int bits ) {
	int			value;
	int			get;
	qboolean	sgn;
	int			i, nbits;
//	FILE*	fp;

	value = 0;

	if ( bits < 0 ) {
		bits = -bits;
		sgn = qtrue;
	} else {
		sgn = qfalse;
	}

	if (msg->oob) {
		if (bits==8) {
			value = msg->data[msg->readcount];
			msg->readcount += 1;
			msg->bit += 8;
		} else if (bits==16) {
			unsigned short *sp = (unsigned short *)&msg->data[msg->readcount];
			value = LittleShort(*sp);
			msg->readcount += 2;
			msg->bit += 16;
		} else if (bits==32) {
			unsigned int *ip = (unsigned int *)&msg->data[msg->readcount];
			value = LittleLong(*ip);
			msg->readcount += 4;
			msg->bit += 32;
		} else {
			Com_Error(ERR_DROP, "can't read %d bits\n", bits);
		}
	} else {
		nbits = 0;
		if (bits&7) {
			nbits = bits&7;
			for(i=0;i<nbits;i++) {
				value |= (Huff_getBit(msg->data, &msg->bit)<<i);
			}
			bits = bits - nbits;
		}
		if (bits) {
//			fp = fopen("c:\\netchan.bin", "a");
			for(i=0;i<bits;i+=8) {
				Huff_offsetReceive (msgHuff.decompressor.tree, &get, msg->data, &msg->bit);
//				fwrite(&get, 1, 1, fp);
				value |= (get<<(i+nbits));
			}
//			fclose(fp);
		}
		msg->readcount = (msg->bit>>3)+1;
	}
	if ( sgn ) {
		if ( value & ( 1 << ( bits - 1 ) ) ) {
			value |= -1 ^ ( ( 1 << bits ) - 1 );
		}
	}

	return value;
}



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

//
// writing functions
//

void MSG_WriteChar( msg_t *sb, int c ) {
#ifdef PARANOID
	if (c < -128 || c > 127)
		Com_Error (ERR_FATAL, "MSG_WriteChar: range error");
#endif

	MSG_WriteBits( sb, c, 8 );
}

void MSG_WriteByte( msg_t *sb, int c ) {
#ifdef PARANOID
	if (c < 0 || c > 255)
		Com_Error (ERR_FATAL, "MSG_WriteByte: range error");
#endif

	MSG_WriteBits( sb, c, 8 );
}

void MSG_WriteData( msg_t *buf, const void *data, int length ) {
	int i;
	for(i=0;i<length;i++) {
		MSG_WriteByte(buf, ((byte *)data)[i]);
	}
}

void MSG_WriteShort( msg_t *sb, int c ) {
#ifdef PARANOID
	if (c < ((short)0x8000) || c > (short)0x7fff)
		Com_Error (ERR_FATAL, "MSG_WriteShort: range error");
#endif

	MSG_WriteBits( sb, c, 16 );
}

void MSG_WriteLong( msg_t *sb, int c ) {
	MSG_WriteBits( sb, c, 32 );
}

void MSG_WriteFloat( msg_t *sb, float f ) {
	union {
		float	f;
		int	l;
	} dat;
	
	dat.f = f;
	MSG_WriteBits( sb, dat.l, 32 );
}

void MSG_WriteString( msg_t *sb, const char *s ) {
	if ( !s ) {
		MSG_WriteData (sb, "", 1);
	} else {
		int		l,i;
		char	string[MAX_STRING_CHARS];

		l = strlen( s );
		if ( l >= MAX_STRING_CHARS ) {
			Com_Printf( "MSG_WriteString: MAX_STRING_CHARS" );
			MSG_WriteData (sb, "", 1);
			return;
		}
		Q_strncpyz( string, s, sizeof( string ) );

		// get rid of 0xff chars, because old clients don't like them
		for ( i = 0 ; i < l ; i++ ) {
			if ( ((byte *)string)[i] > 127 ) {
				string[i] = '.';
			}
		}

		MSG_WriteData (sb, string, l+1);
	}
}

void MSG_WriteBigString( msg_t *sb, const char *s ) {
	if ( !s ) {
		MSG_WriteData (sb, "", 1);
	} else {
		int		l,i;
		char	string[BIG_INFO_STRING];

		l = strlen( s );
		if ( l >= BIG_INFO_STRING ) {
			Com_Printf( "MSG_WriteString: BIG_INFO_STRING" );
			MSG_WriteData (sb, "", 1);
			return;
		}
		Q_strncpyz( string, s, sizeof( string ) );

		// get rid of 0xff chars, because old clients don't like them
		for ( i = 0 ; i < l ; i++ ) {
			if ( ((byte *)string)[i] > 127 ) {
				string[i] = '.';
			}
		}

		MSG_WriteData (sb, string, l+1);
	}
}

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

void MSG_WriteAngle16( msg_t *sb, float f ) {
	MSG_WriteShort (sb, ANGLE2SHORT(f));
}


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

//
// reading functions
//

// returns -1 if no more characters are available
int MSG_ReadChar (msg_t *msg ) {
	int	c;
	
	c = (signed char)MSG_ReadBits( msg, 8 );
	if ( msg->readcount > msg->cursize ) {
		c = -1;
	}	
	
	return c;
}

int MSG_ReadByte( msg_t *msg ) {
	int	c;
	
	c = (unsigned char)MSG_ReadBits( msg, 8 );
	if ( msg->readcount > msg->cursize ) {
		c = -1;
	}	
	return c;
}

int MSG_ReadShort( msg_t *msg ) {
	int	c;
	
	c = (short)MSG_ReadBits( msg, 16 );
	if ( msg->readcount > msg->cursize ) {
		c = -1;
	}	

	return c;
}

int MSG_ReadLong( msg_t *msg ) {
	int	c;
	
	c = MSG_ReadBits( msg, 32 );
	if ( msg->readcount > msg->cursize ) {
		c = -1;
	}	
	
	return c;
}

float MSG_ReadFloat( msg_t *msg ) {
	union {
		byte	b[4];
		float	f;
		int	l;
	} dat;
	
	dat.l = MSG_ReadBits( msg, 32 );
	if ( msg->readcount > msg->cursize ) {
		dat.f = -1;
	}	
	
	return dat.f;	
}

char *MSG_ReadString( msg_t *msg ) {
	static char	string[MAX_STRING_CHARS];
	int		l,c;
	
	l = 0;
	do {
		c = MSG_ReadByte(msg);		// use ReadByte so -1 is out of bounds
		if ( c == -1 || c == 0 ) {
			break;
		}
		// translate all fmt spec to avoid crash bugs
		if ( c == '%' ) {
			c = '.';
		}
		// don't allow higher ascii values
		if ( c > 127 ) {
			c = '.';
		}

		string[l] = c;
		l++;
	} while (l < sizeof(string)-1);
	
	string[l] = 0;
	
	return string;
}

char *MSG_ReadBigString( msg_t *msg ) {
	static char	string[BIG_INFO_STRING];
	int		l,c;
	
	l = 0;
	do {
		c = MSG_ReadByte(msg);		// use ReadByte so -1 is out of bounds
		if ( c == -1 || c == 0 ) {
			break;
		}
		// translate all fmt spec to avoid crash bugs
		if ( c == '%' ) {
			c = '.';
		}

		string[l] = c;
		l++;
	} while (l < sizeof(string)-1);
	
	string[l] = 0;
	
	return string;
}

char *MSG_ReadStringLine( msg_t *msg ) {
	static char	string[MAX_STRING_CHARS];
	int		l,c;

	l = 0;
	do {
		c = MSG_ReadByte(msg);		// use ReadByte so -1 is out of bounds
		if (c == -1 || c == 0 || c == '\n') {
			break;
		}
		// translate all fmt spec to avoid crash bugs
		if ( c == '%' ) {
			c = '.';
		}
		string[l] = c;
		l++;
	} while (l < sizeof(string)-1);
	
	string[l] = 0;
	
	return string;
}

float MSG_ReadAngle16( msg_t *msg ) {
	return SHORT2ANGLE(MSG_ReadShort(msg));
}

void MSG_ReadData( msg_t *msg, void *data, int len ) {
	int		i;

	for (i=0 ; i<len ; i++) {
		((byte *)data)[i] = MSG_ReadByte (msg);
	}
}


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

delta functions
  
=============================================================================
*/

extern cvar_t *cl_shownet;

#define	LOG(x) if( cl_shownet->integer == 4 ) { Com_Printf("%s ", x ); };

void MSG_WriteDelta( msg_t *msg, int oldV, int newV, int bits ) {
	if ( oldV == newV ) {
		MSG_WriteBits( msg, 0, 1 );
		return;
	}
	MSG_WriteBits( msg, 1, 1 );
	MSG_WriteBits( msg, newV, bits );
}

int	MSG_ReadDelta( msg_t *msg, int oldV, int bits ) {
	if ( MSG_ReadBits( msg, 1 ) ) {
		return MSG_ReadBits( msg, bits );
	}
	return oldV;
}

void MSG_WriteDeltaFloat( msg_t *msg, float oldV, float newV ) {
	if ( oldV == newV ) {
		MSG_WriteBits( msg, 0, 1 );
		return;
	}
	MSG_WriteBits( msg, 1, 1 );
	MSG_WriteBits( msg, *(int *)&newV, 32 );
}

float MSG_ReadDeltaFloat( msg_t *msg, float oldV ) {
	if ( MSG_ReadBits( msg, 1 ) ) {
		float	newV;

		*(int *)&newV = MSG_ReadBits( msg, 32 );
		return newV;
	}
	return oldV;
}

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

delta functions with keys
  
=============================================================================
*/

int kbitmask[32] = {
	0x00000001, 0x00000003, 0x00000007, 0x0000000F,
	0x0000001F,	0x0000003F,	0x0000007F,	0x000000FF,
	0x000001FF,	0x000003FF,	0x000007FF,	0x00000FFF,
	0x00001FFF,	0x00003FFF,	0x00007FFF,	0x0000FFFF,
	0x0001FFFF,	0x0003FFFF,	0x0007FFFF,	0x000FFFFF,
	0x001FFFFf,	0x003FFFFF,	0x007FFFFF,	0x00FFFFFF,
	0x01FFFFFF,	0x03FFFFFF,	0x07FFFFFF,	0x0FFFFFFF,
	0x1FFFFFFF,	0x3FFFFFFF,	0x7FFFFFFF,	0xFFFFFFFF,
};

void MSG_WriteDeltaKey( msg_t *msg, int key, int oldV, int newV, int bits ) {
	if ( oldV == newV ) {
		MSG_WriteBits( msg, 0, 1 );
		return;