cnq3/code/qcommon/msg.cpp

/*
===========================================================================
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 "q_shared.h"
#include "qcommon.h"


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

			MESSAGE IO FUNCTIONS

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


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

void MSG_InitOOB( msg_t *buf, byte *data, int length ) {
	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, const 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

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

//static int overflows;

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

	// 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 );
	}

	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 += 32;
		} else {
			Com_Error(ERR_DROP, "can't write %d bits\n", bits);
		}
	} else {
		value &= (0xffffffff>>(32-bits));
		if (bits&7) {
			int nbits;
			nbits = bits&7;
			bitIndex = msg->bit;
			for(i=0;i<nbits;i++) {
				StatHuff_WriteBit((value & 1), msg->data, bitIndex);
				value = (value>>1);
				bitIndex++;
			}
			msg->bit = bitIndex;
			bits = bits - nbits;
		}
		if (bits) {
			bitIndex = msg->bit;
			for(i=0;i<bits;i+=8) {
				bitIndex += StatHuff_WriteSymbol((value & 0xff), msg->data, bitIndex);
				value = (value>>8);
			}
			msg->bit = bitIndex;
		}
		msg->cursize = (msg->bit>>3)+1;
	}
}

int MSG_ReadBits( msg_t *msg, int bits ) {
	int			value;
	int			get;
	qbool		sgn;
	int			i, nbits, bitIndex;

	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_NDP, "can't read %d bits\n", bits);
		}
	} else {
		nbits = 0;
		if (bits&7) {
			nbits = bits&7;
			bitIndex = msg->bit;
			for(i=0;i<nbits;i++) {
				value |= StatHuff_ReadBit(msg->data, bitIndex) << i;
				bitIndex++;
			}
			msg->bit = bitIndex;
			bits = bits - nbits;
		}
		if (bits) {
			bitIndex = msg->bit;
			for(i=0;i<bits;i+=8) {
				bitIndex += StatHuff_ReadSymbol(&get, msg->data, bitIndex);
				value |= (get<<(i+nbits));
			}
			msg->bit = bitIndex;
		}
		msg->readcount = (msg->bit>>3)+1;
	}
	if ( sgn ) {
		if ( value & ( 1 << ( bits - 1 ) ) ) {
			value |= -1 ^ ( ( 1 << bits ) - 1 );
		}
	}

	return value;
}


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


//
// writing functions
//

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_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);
	}
}


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

//
// reading functions: return -1 if no more characters are available
//

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

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

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

//
// Notes about the MSG_Read*String* functions
//
// If N is the string buffer size, then:
// - the max. string length is N-1 because
//   the NULL-terminator is part of the buffer
// - the loop can call MSG_ReadByte at most N times
// - the loop can write at most N-1 chars
//   to leave space for the NULL terminator
//
// The "q3msgboom" bug was happening because a string
// of length >= N-1 was invoking MSG_ReadByte N-1 times
// instead of N times, leaving the bit stream in an
// invalid state and later leading to the
// "Illegible server message" drop error.
//

char *MSG_ReadString( msg_t *msg ) {
	static char	string[MAX_STRING_CHARS];

	int l = 0;
	for (;;) {
		const int c = MSG_ReadByte(msg);
		if (c <= 0 || l >= sizeof(string) - 1)
			break;

		string[l++] = c == '%' || c > 127 ? '.' : c;
	}
	string[l] = '\0';

	return string;
}

char *MSG_ReadBigString( msg_t *msg ) {
	static char	string[BIG_INFO_STRING];

	int l = 0;
	for (;;) {
		const int c = MSG_ReadByte(msg);
		if (c <= 0 || l >= sizeof(string) - 1)
			break;

		string[l++] = c == '%' || c > 127 ? '.' : c;
	}
	string[l] = '\0';

	return string;
}

char *MSG_ReadStringLine( msg_t *msg ) {
	static char	string[MAX_STRING_CHARS];

	int l = 0;
	for (;;) {
		const int c = MSG_ReadByte(msg);
		if (c <= 0 || c == '\n' || l >= sizeof(string) - 1)
			break;

		string[l++] = c == '%' || c > 127 ? '.' : c;
	}
	string[l] = '\0';
	
	return string;
}

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 with keys

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

#ifndef DEDICATED
extern cvar_t* cl_shownet;
#define NETLOG(x) if ( cl_shownet->integer == 4 ) { Com_Printf("%s ", x ); };
#else
#define NETLOG(x) 
#endif

static const 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,	int(0xFFFFFFFF),
};

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

static int MSG_ReadDeltaKey( msg_t *msg, int key, int oldV, int bits )
{
	if ( MSG_ReadBits( msg, 1 ) ) {
		return MSG_ReadBits( msg, bits ) ^ (key & kbitmask[bits]);
	}
	return oldV;
}


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

usercmd_t communication
ucmds always have time, then either all fields or none

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


void MSG_WriteDeltaUsercmdKey( msg_t* msg, int key, const usercmd_t* from, usercmd_t* to )
{
	if ( to->serverTime - from->serverTime < 256 ) {
		MSG_WriteBits( msg, 1, 1 );
		MSG_WriteBits( msg, to->serverTime - from->serverTime, 8 );
	} else {
		MSG_WriteBits( msg, 0, 1 );
		MSG_WriteBits( msg, to->serverTime, 32 );
	}
	if (from->angles[0] == to->angles[0] &&
		from->angles[1] == to->angles[1] &&
		from->angles[2] == to->angles[2] &&
		from->forwardmove == to->forwardmove &&
		from->rightmove == to->rightmove &&
		from->upmove == to->upmove &&
		from->buttons == to->buttons &&
		from->weapon == to->weapon) {
			MSG_WriteBits( msg, 0, 1 );				// no change
			return;
	}
    
	key ^= to->serverTime;
	MSG_WriteBits( msg, 1, 1 );
	MSG_WriteDeltaKey( msg, key, from->angles[0], to->angles[0], 16 );
	MSG_WriteDeltaKey( msg, key, from->angles[1], to->angles[1], 16 );
	MSG_WriteDeltaKey( msg, key, from->angles[2], to->angles[2], 16 );
	MSG_WriteDeltaKey( msg, key, from->forwardmove, to->forwardmove, 8 );
	MSG_WriteDeltaKey( msg, key, from->rightmove, to->rightmove, 8 );
	MSG_WriteDeltaKey( msg, key, from->upmove, to->upmove, 8 );
	MSG_WriteDeltaKey( msg, key, from->buttons, to->buttons, 16 );
	MSG_WriteDeltaKey( msg, key, from->weapon, to->weapon, 8 );
}


void MSG_ReadDeltaUsercmdKey( msg_t* msg, int key, const usercmd_t* from, usercmd_t* to )
{
	if ( MSG_ReadBits( msg, 1 ) ) {
		to->serverTime = from->serverTime + MSG_ReadBits( msg, 8 );
	} else {
		to->serverTime = MSG_ReadBits( msg, 32 );
	}
	if ( MSG_ReadBits( msg, 1 ) ) {
		key ^= to->serverTime;
		to->angles[0] = MSG_ReadDeltaKey( msg, key, from->angles[0], 16);
		to->angles[1] = MSG_ReadDeltaKey( msg, key, from->angles[1], 16);
		to->angles[2] = MSG_ReadDeltaKey( msg, key, from->angles[2], 16);
		to->forwardmove = MSG_ReadDeltaKey( msg, key, from->forwardmove, 8);
		to->rightmove = MSG_ReadDeltaKey( msg, key, from->rightmove, 8);
		to->upmove = MSG_ReadDeltaKey( msg, key, from->upmove, 8);
		to->buttons = MSG_ReadDeltaKey( msg, key, from->buttons, 16);
		to->weapon = MSG_ReadDeltaKey( msg, key, from->weapon, 8);
	} else {
		to->angles[0] = from->angles[0];
		to->angles[1] = from->angles[1];
		to->angles[2] = from->angles[2];
		to->forwardmove = from->forwardmove;
		to->rightmove = from->rightmove;
		to->upmove = from->upmove;
		to->buttons = from->buttons;
		to->weapon = from->weapon;
	}
}


///////////////////////////////////////////////////////////////


// if (int)f == f and (int)f + ( 1<<(FLOAT_INT_BITS-1) ) < ( 1 << FLOAT_INT_BITS )
// the float will be sent with FLOAT_INT_BITS, otherwise all 32 bits will be sent
#define	FLOAT_INT_BITS	13
#define	FLOAT_INT_BIAS	(1<<(FLOAT_INT_BITS-1))

typedef struct {
	const char* name;
	size_t		offset;
	int			bits;		// 0 = float
} netField_t;


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

entityState_t communication

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

// using the stringizing operator to save typing...
#define ESF(x) #x,(size_t)&((entityState_t*)0)->x

static const netField_t entityStateFields[] =
{
{ ESF(pos.trTime), 32 },
{ ESF(pos.trBase[0]), 0 },
{ ESF(pos.trBase[1]), 0 },
{ ESF(pos.trDelta[0]), 0 },
{ ESF(pos.trDelta[1]), 0 },
{ ESF(pos.trBase[2]), 0 },
{ ESF(apos.trBase[1]), 0 },
{ ESF(pos.trDelta[2]), 0 },
{ ESF(apos.trBase[0]), 0 },
{ ESF(event), 10 },
{ ESF(angles2[1]), 0 },
{ ESF(eType), 8 },
{ ESF(torsoAnim), 8 },
{ ESF(eventParm), 8 },
{ ESF(legsAnim), 8 },
{ ESF(groundEntityNum), GENTITYNUM_BITS },
{ ESF(pos.trType), 8 },
{ ESF(eFlags), 19 },
{ ESF(otherEntityNum), GENTITYNUM_BITS },
{ ESF(weapon), 8 },
{ ESF(clientNum), 8 },
{ ESF(angles[1]), 0 },
{ ESF(pos.trDuration), 32 },
{ ESF(apos.trType), 8 },
{ ESF(origin[0]), 0 },
{ ESF(origin[1]), 0 },
{ ESF(origin[2]), 0 },
{ ESF(solid), 24 },
{ ESF(powerups), MAX_POWERUPS },
{ ESF(modelindex), 8 },
{ ESF(otherEntityNum2), GENTITYNUM_BITS },
{ ESF(loopSound), 8 },
{ ESF(generic1), 8 },
{ ESF(origin2[2]), 0 },
{ ESF(origin2[0]), 0 },
{ ESF(origin2[1]), 0 },
{ ESF(modelindex2), 8 },
{ ESF(angles[0]), 0 },
{ ESF(time), 32 },
{ ESF(apos.trTime), 32 },
{ ESF(apos.trDuration), 32 },
{ ESF(apos.trBase[2]), 0 },
{ ESF(apos.trDelta[0]), 0 },
{ ESF(apos.trDelta[1]), 0 },
{ ESF(apos.trDelta[2]), 0 },
{ ESF(time2), 32 },
{ ESF(angles[2]), 0 },
{ ESF(angles2[0]), 0 },
{ ESF(angles2[2]), 0 },
{ ESF(constantLight), 32 },
{ ESF(frame), 16 }
};

static const int numESF = sizeof(entityStateFields) / sizeof(entityStateFields[0]);


/*
==================
MSG_WriteDeltaEntity

Writes part of a packetentities message, including the entity number.
Can delta from either a baseline or a previous packet_entity
If to is NULL, a remove entity update will be sent
If force is not set, then nothing at all will be generated if the entity is
identical, under the assumption that the in-order delta code will catch it.
==================
*/
void MSG_WriteDeltaEntity( msg_t* msg, const entityState_t* from, const entityState_t* to, qbool force )
{
	int			i, lc;
	int			*fromF, *toF;

	// all fields should be 32 bits to avoid any compiler packing issues
	// the "number" field is not part of the field list
	// if this assert fails, someone added a field to the entityState_t
	// struct without updating the message fields
	COMPILE_TIME_ASSERT( numESF + 1 == sizeof(*from) / 4 );

	// a NULL to is a delta remove message
	if ( to == NULL ) {
		if ( from == NULL ) {
			return;
		}
		MSG_WriteBits( msg, from->number, GENTITYNUM_BITS );
		MSG_WriteBits( msg, 1, 1 );
		return;
	}

	if ( to->number < 0 || to->number >= MAX_GENTITIES ) {
		Com_Error( ERR_FATAL, "MSG_WriteDeltaEntity: Bad entity number: %i", to->number );
	}

	lc = 0;
	const netField_t* field;
	// build the change vector as bytes so it is endien independent
	for ( i = 0, field = entityStateFields ; i < numESF ; i++, field++ ) {
		fromF = (int *)( (byte *)from + field->offset );
		toF = (int *)( (byte *)to + field->offset );
		if ( *fromF != *toF ) {
			lc = i+1;
		}
	}

	if ( lc == 0 ) {
		// nothing at all changed
		if ( !force ) {
			return;		// nothing at all
		}
		// write two bits for no change
		MSG_WriteBits( msg, to->number, GENTITYNUM_BITS );
		MSG_WriteBits( msg, 0, 1 );		// not removed
		MSG_WriteBits( msg, 0, 1 );		// no delta
		return;
	}

	MSG_WriteBits( msg, to->number, GENTITYNUM_BITS );
	MSG_WriteBits( msg, 0, 1 );			// not removed
	MSG_WriteBits( msg, 1, 1 );			// we have a delta

	MSG_WriteByte( msg, lc );	// # of changes

	for ( i = 0, field = entityStateFields ; i < lc ; i++, field++ ) {
		fromF = (int *)( (byte *)from + field->offset );
		toF = (int *)( (byte *)to + field->offset );

		if ( *fromF == *toF ) {
			MSG_WriteBits( msg, 0, 1 );	// no change
			continue;
		}

		MSG_WriteBits( msg, 1, 1 );	// changed

		if ( field->bits == 0 ) {
			float fullFloat = *(float *)toF;

			if (fullFloat == 0.0f) {
				MSG_WriteBits( msg, 0, 1 );
			} else {
				MSG_WriteBits( msg, 1, 1 );
				int trunc = (int)fullFloat;
				if ( trunc == fullFloat && trunc + FLOAT_INT_BIAS >= 0 && 
					trunc + FLOAT_INT_BIAS < ( 1 << FLOAT_INT_BITS ) ) {
					// send as small integer
					MSG_WriteBits( msg, 0, 1 );
					MSG_WriteBits( msg, trunc + FLOAT_INT_BIAS, FLOAT_INT_BITS );
				} else {
					// send as full floating point value
					MSG_WriteBits( msg, 1, 1 );
					MSG_WriteBits( msg, *toF, 32 );
				}
			}
		} else {
			if (*toF == 0) {
				MSG_WriteBits( msg, 0, 1 );
			} else {
				MSG_WriteBits( msg, 1, 1 );
				// integer
				MSG_WriteBits( msg, *toF, field->bits );
			}
		}
	}
}

/*
==================
MSG_ReadDeltaEntity

The entity number has already been read from the message, which
is how the from state is identified.

If the delta removes the entity, entityState_t->number will be set to MAX_GENTITIES-1

Can go from either a baseline or a previous packet_entity
==================
*/

void MSG_ReadDeltaEntity( msg_t* msg, const entityState_t* from, entityState_t* to, int number )
{
	int			i, lc;
	int			*fromF, *toF;
	int			print;
	int			startBit, endBit;

	if ( number < 0 || number >= MAX_GENTITIES ) {
		Com_Error( ERR_DROP_NDP, "Bad delta entity number: %i", number );
	}

	if ( msg->bit == 0 ) {
		startBit = msg->readcount * 8 - GENTITYNUM_BITS;
	} else {
		startBit = ( msg->readcount - 1 ) * 8 + msg->bit - GENTITYNUM_BITS;
	}

	// check for a remove
	if ( MSG_ReadBits( msg, 1 ) == 1 ) {
		Com_Memset( to, 0, sizeof( *to ) );
		to->number = MAX_GENTITIES - 1;
#ifndef DEDICATED
		if ( cl_shownet->integer >= 2 || cl_shownet->integer == -1 ) {
			Com_Printf( "%3i: #%-3i remove\n", msg->readcount, number );
		}
#endif
		return;
	}

	// check for no delta
	if ( MSG_ReadBits( msg, 1 ) == 0 ) {
		*to = *from;
		to->number = number;
		return;
	}

	lc = MSG_ReadByte(msg);
	if ( lc < 0 || lc > ARRAY_LEN(entityStateFields) ) {
		Com_Error( ERR_DROP_NDP, "invalid entityState_t field count %d (max: %d)\n", lc, ARRAY_LEN(entityStateFields) );
	}

	// shownet 2/3 will interleave with other printed info, -1 will
	// just print the delta records
#ifndef DEDICATED
	if ( cl_shownet->integer >= 2 || cl_shownet->integer == -1 ) {
		print = 1;
		Com_Printf( "%3i: #%-3i ", msg->readcount, to->number );
	} else {
		print = 0;
	}
#else
	print = 0;
#endif

	to->number = number;

	const netField_t* field;
	for ( i = 0, field = entityStateFields ; i < lc ; i++, field++ ) {
		fromF = (int *)( (byte *)from + field->offset );
		toF = (int *)( (byte *)to + field->offset );

		if ( ! MSG_ReadBits( msg, 1 ) ) {
			// no change
			*toF = *fromF;
		} else {
			if ( field->bits == 0 ) {
				// float
				if ( MSG_ReadBits( msg, 1 ) == 0 ) {
					*(float *)toF = 0.0f;
				} else {
					if ( MSG_ReadBits( msg, 1 ) == 0 ) {
						// integral float
						int trunc = MSG_ReadBits( msg, FLOAT_INT_BITS );
						// bias to allow equal parts positive and negative
						trunc -= FLOAT_INT_BIAS;
						*(float *)toF = trunc; 
						if ( print ) {
							Com_Printf( "%s:%i ", field->name, trunc );
						}
					} else {
						// full floating point value
						*toF = MSG_ReadBits( msg, 32 );
						if ( print ) {
							Com_Printf( "%s:%f ", field->name, *(float *)toF );
						}
					}
				}
			} else {
				if ( MSG_ReadBits( msg, 1 ) == 0 ) {
					*toF = 0;
				} else {
					// integer
					*toF = MSG_ReadBits( msg, field->bits );
					if ( print ) {
						Com_Printf( "%s:%i ", field->name, *toF );
					}
				}
			}
//			pcount[i]++;
		}
	}
	for ( i = lc, field = &entityStateFields[lc] ; i < numESF ; i++, field++ ) {
		fromF = (int *)( (byte *)from + field->offset );
		toF = (int *)( (byte *)to + field->offset );
		// no change
		*toF = *fromF;
	}

	if ( print ) {
		if ( msg->bit == 0 ) {
			endBit = msg->readcount * 8 - GENTITYNUM_BITS;
		} else {
			endBit = ( msg->readcount - 1 ) * 8 + msg->bit - GENTITYNUM_BITS;
		}
		Com_Printf( " (%i bits)\n", endBit - startBit  );
	}
}


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

plyer_state_t communication

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

// using the stringizing operator to save typing...
#define PSF(x) #x,(size_t)&((playerState_t*)0)->x

static const netField_t playerStateFields[] =
{
{ PSF(commandTime), 32 },
{ PSF(origin[0]), 0 },
{ PSF(origin[1]), 0 },
{ PSF(bobCycle), 8 },
{ PSF(velocity[0]), 0 },
{ PSF(velocity[1]), 0 },
{ PSF(viewangles[1]), 0 },
{ PSF(viewangles[0]), 0 },
{ PSF(weaponTime), -16 },
{ PSF(origin[2]), 0 },
{ PSF(velocity[2]), 0 },
{ PSF(legsTimer), 8 },
{ PSF(pm_time), -16 },
{ PSF(eventSequence), 16 },
{ PSF(torsoAnim), 8 },
{ PSF(movementDir), 4 },
{ PSF(events[0]), 8 },
{ PSF(legsAnim), 8 },
{ PSF(events[1]), 8 },
{ PSF(pm_flags), 16 },
{ PSF(groundEntityNum), GENTITYNUM_BITS },
{ PSF(weaponstate), 4 },
{ PSF(eFlags), 16 },
{ PSF(externalEvent), 10 },
{ PSF(gravity), 16 },
{ PSF(speed), 16 },
{ PSF(delta_angles[1]), 16 },
{ PSF(externalEventParm), 8 },
{ PSF(viewheight), -8 },
{ PSF(damageEvent), 8 },
{ PSF(damageYaw), 8 },
{ PSF(damagePitch), 8 },
{ PSF(damageCount), 8 },
{ PSF(generic1), 8 },
{ PSF(pm_type), 8 },
{ PSF(delta_angles[0]), 16 },
{ PSF(delta_angles[2]), 16 },
{ PSF(torsoTimer), 12 },
{ PSF(eventParms[0]), 8 },
{ PSF(eventParms[1]), 8 },
{ PSF(clientNum), 8 },
{ PSF(weapon), 5 },
{ PSF(viewangles[2]), 0 },
{ PSF(grapplePoint[0]), 0 },
{ PSF(grapplePoint[1]), 0 },
{ PSF(grapplePoint[2]), 0 },
{ PSF(jumppad_ent), 10 },
{ PSF(loopSound), 16 }
};

static const int numPSF = sizeof(playerStateFields) / sizeof(playerStateFields[0]);


void MSG_WriteDeltaPlayerstate( msg_t* msg, const playerState_t* from, playerState_t* to )
{
	int				i;
	playerState_t	dummy;
	int				c;
	int				*fromF, *toF;
	int				lc;

	if (!from) {
		from = &dummy;
		Com_Memset (&dummy, 0, sizeof(dummy));
	}

	c = msg->cursize;

	lc = 0;
	const netField_t* field;
	for ( i = 0, field = playerStateFields ; i < numPSF ; i++, field++ ) {
		fromF = (int *)( (byte *)from + field->offset );
		toF = (int *)( (byte *)to + field->offset );
		if ( *fromF != *toF ) {
			lc = i+1;
		}
	}

	MSG_WriteByte( msg, lc );	// # of changes

	for ( i = 0, field = playerStateFields ; i < lc ; i++, field++ ) {
		fromF = (int *)( (byte *)from + field->offset );
		toF = (int *)( (byte *)to + field->offset );

		if ( *fromF == *toF ) {
			MSG_WriteBits( msg, 0, 1 );	// no change
			continue;
		}

		MSG_WriteBits( msg, 1, 1 );	// changed
//		pcount[i]++;

		if ( field->bits == 0 ) {
			float fullFloat = *(float *)toF;
			int trunc = (int)fullFloat;

			if ( trunc == fullFloat && trunc + FLOAT_INT_BIAS >= 0 && 
				trunc + FLOAT_INT_BIAS < ( 1 << FLOAT_INT_BITS ) ) {
				// send as small integer
				MSG_WriteBits( msg, 0, 1 );
				MSG_WriteBits( msg, trunc + FLOAT_INT_BIAS, FLOAT_INT_BITS );
			} else {
				// send as full floating point value
				MSG_WriteBits( msg, 1, 1 );
				MSG_WriteBits( msg, *toF, 32 );
			}
		} else {
			// integer
			MSG_WriteBits( msg, *toF, field->bits );
		}
	}
	c = msg->cursize - c;


	//
	// send the arrays
	//
	int statsbits = 0;
	for (i=0 ; i<MAX_STATS ; i++) {
		if (to->stats[i] != from->stats[i]) {
			statsbits |= 1<<i;
		}
	}
	int persistantbits = 0;
	for (i=0 ; i<MAX_PERSISTANT ; i++) {
		if (to->persistant[i] != from->persistant[i]) {
			persistantbits |= 1<<i;
		}
	}
	int ammobits = 0;
	for (i=0 ; i<MAX_WEAPONS ; i++) {
		if (to->ammo[i] != from->ammo[i]) {
			ammobits |= 1<<i;
		}
	}
	int powerupbits = 0;
	for (i=0 ; i<MAX_POWERUPS ; i++) {
		if (to->powerups[i] != from->powerups[i]) {
			powerupbits |= 1<<i;
		}
	}

	if (!statsbits && !persistantbits && !ammobits && !powerupbits) {
		MSG_WriteBits( msg, 0, 1 );	// no change
		return;
	}
	MSG_WriteBits( msg, 1, 1 );	// changed

	if ( statsbits ) {
		MSG_WriteBits( msg, 1, 1 );	// changed
		MSG_WriteBits( msg, statsbits, MAX_STATS );
		for (i=0 ; i<MAX_STATS ; i++)
			if (statsbits & (1<<i) )
				MSG_WriteShort (msg, to->stats[i]);
	} else {
		MSG_WriteBits( msg, 0, 1 );	// no change
	}


	if ( persistantbits ) {
		MSG_WriteBits( msg, 1, 1 );	// changed
		MSG_WriteBits( msg, persistantbits, MAX_PERSISTANT );
		for (i=0 ; i<MAX_PERSISTANT ; i++)
			if (persistantbits & (1<<i) )
				MSG_WriteShort (msg, to->persistant[i]);
	} else {
		MSG_WriteBits( msg, 0, 1 );	// no change
	}


	if ( ammobits ) {
		MSG_WriteBits( msg, 1, 1 );	// changed
		MSG_WriteBits( msg, ammobits, MAX_WEAPONS );
		for (i=0 ; i<MAX_WEAPONS ; i++)
			if (ammobits & (1<<i) )
				MSG_WriteShort (msg, to->ammo[i]);
	} else {
		MSG_WriteBits( msg, 0, 1 );	// no change
	}


	if ( powerupbits ) {
		MSG_WriteBits( msg, 1, 1 );	// changed
		MSG_WriteBits( msg, powerupbits, MAX_POWERUPS );
		for (i=0 ; i<MAX_POWERUPS ; i++)
			if (powerupbits & (1<<i) )
				MSG_WriteLong( msg, to->powerups[i] );
	} else {
		MSG_WriteBits( msg, 0, 1 );	// no change
	}
}


void MSG_ReadDeltaPlayerstate( msg_t* msg, const playerState_t* from, playerState_t* to )
{
	int			i, lc;
	int			bits;
	int			startBit, endBit;
	int			print;
	int			*fromF, *toF;
	int			trunc;
	playerState_t	dummy;

	if ( !from ) {
		from = &dummy;
		Com_Memset( &dummy, 0, sizeof( dummy ) );
	}
	*to = *from;

	if ( msg->bit == 0 ) {
		startBit = msg->readcount * 8 - GENTITYNUM_BITS;
	} else {
		startBit = ( msg->readcount - 1 ) * 8 + msg->bit - GENTITYNUM_BITS;
	}

	// shownet 2/3 will interleave with other printed info, -2 will
	// just print the delta records
#ifndef DEDICATED
	if ( cl_shownet->integer >= 2 || cl_shownet->integer == -2 ) {
		print = 1;
		Com_Printf( "%3i: playerstate ", msg->readcount );
	} else {
		print = 0;
	}
#else
	print = 0;
#endif

	lc = MSG_ReadByte(msg);
	if ( lc < 0 || lc > ARRAY_LEN(playerStateFields) ) {
		Com_Error( ERR_DROP_NDP, "invalid playerState_t field count %d (max: %d)\n", lc, ARRAY_LEN(playerStateFields) );
	}

	const netField_t* field;
	for ( i = 0, field = playerStateFields ; i < lc ; i++, field++ ) {
		fromF = (int *)( (byte *)from + field->offset );
		toF = (int *)( (byte *)to + field->offset );

		if ( ! MSG_ReadBits( msg, 1 ) ) {
			// no change
			*toF = *fromF;
		} else {
			if ( field->bits == 0 ) {
				// float
				if ( MSG_ReadBits( msg, 1 ) == 0 ) {
					// integral float
					trunc = MSG_ReadBits( msg, FLOAT_INT_BITS );
					// bias to allow equal parts positive and negative
					trunc -= FLOAT_INT_BIAS;
					*(float *)toF = trunc; 
					if ( print ) {
						Com_Printf( "%s:%i ", field->name, trunc );
					}
				} else {
					// full floating point value
					*toF = MSG_ReadBits( msg, 32 );
					if ( print ) {
						Com_Printf( "%s:%f ", field->name, *(float *)toF );
					}
				}
			} else {
				// integer
				*toF = MSG_ReadBits( msg, field->bits );
				if ( print ) {
					Com_Printf( "%s:%i ", field->name, *toF );
				}
			}
		}
	}
	for ( i = lc, field = &playerStateFields[lc] ; i < numPSF ; i++, field++ ) {
		fromF = (int *)( (byte *)from + field->offset );
		toF = (int *)( (byte *)to + field->offset );
		// no change
		*toF = *fromF;
	}


	// read the arrays
	if (MSG_ReadBits( msg, 1 ) ) {
		// parse stats
		if ( MSG_ReadBits( msg, 1 ) ) {
			NETLOG("PS_STATS");
			bits = MSG_ReadBits (msg, MAX_STATS);
			for (i=0 ; i<MAX_STATS ; i++) {
				if (bits & (1<<i) ) {
					to->stats[i] = MSG_ReadShort(msg);
				}
			}
		}

		// parse persistant stats
		if ( MSG_ReadBits( msg, 1 ) ) {
			NETLOG("PS_PERSISTANT");
			bits = MSG_ReadBits (msg, MAX_PERSISTANT);
			for (i=0 ; i<MAX_PERSISTANT ; i++) {
				if (bits & (1<<i) ) {
					to->persistant[i] = MSG_ReadShort(msg);
				}
			}
		}

		// parse ammo
		if ( MSG_ReadBits( msg, 1 ) ) {
			NETLOG("PS_AMMO");
			bits = MSG_ReadBits (msg, MAX_WEAPONS);
			for (i=0 ; i<MAX_WEAPONS ; i++) {
				if (bits & (1<<i) ) {
					to->ammo[i] = MSG_ReadShort(msg);
				}
			}
		}

		// parse powerups
		if ( MSG_ReadBits( msg, 1 ) ) {
			NETLOG("PS_POWERUPS");
			bits = MSG_ReadBits (msg, MAX_POWERUPS);
			for (i=0 ; i<MAX_POWERUPS ; i++) {
				if (bits & (1<<i) ) {
					to->powerups[i] = MSG_ReadLong(msg);
				}
			}
		}
	}

	if ( print ) {
		if ( msg->bit == 0 ) {
			endBit = msg->readcount * 8 - GENTITYNUM_BITS;
		} else {
			endBit = ( msg->readcount - 1 ) * 8 + msg->bit - GENTITYNUM_BITS;
		}
		Com_Printf( " (%i bits)\n", endBit - startBit  );
	}
}