cl_parse.c

quakeIII源码这个不用我多说吧

/*
===========================================================================
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
===========================================================================
*/
// cl_parse.c  -- parse a message received from the server

#include "client.h"

char *svc_strings[256] = {
	"svc_bad",

	"svc_nop",
	"svc_gamestate",
	"svc_configstring",
	"svc_baseline",	
	"svc_serverCommand",
	"svc_download",
	"svc_snapshot"
};

void SHOWNET( msg_t *msg, char *s) {
	if ( cl_shownet->integer >= 2) {
		Com_Printf ("%3i:%s\n", msg->readcount-1, s);
	}
}


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

MESSAGE PARSING

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

/*
==================
CL_DeltaEntity

Parses deltas from the given base and adds the resulting entity
to the current frame
==================
*/
void CL_DeltaEntity (msg_t *msg, clSnapshot_t *frame, int newnum, entityState_t *old, 
					 qboolean unchanged) {
	entityState_t	*state;

	// save the parsed entity state into the big circular buffer so
	// it can be used as the source for a later delta
	state = &cl.parseEntities[cl.parseEntitiesNum & (MAX_PARSE_ENTITIES-1)];

	if ( unchanged ) {
		*state = *old;
	} else {
		MSG_ReadDeltaEntity( msg, old, state, newnum );
	}

	if ( state->number == (MAX_GENTITIES-1) ) {
		return;		// entity was delta removed
	}
	cl.parseEntitiesNum++;
	frame->numEntities++;
}

/*
==================
CL_ParsePacketEntities

==================
*/
void CL_ParsePacketEntities( msg_t *msg, clSnapshot_t *oldframe, clSnapshot_t *newframe) {
	int			newnum;
	entityState_t	*oldstate;
	int			oldindex, oldnum;

	newframe->parseEntitiesNum = cl.parseEntitiesNum;
	newframe->numEntities = 0;

	// delta from the entities present in oldframe
	oldindex = 0;
	oldstate = NULL;
	if (!oldframe) {
		oldnum = 99999;
	} else {
		if ( oldindex >= oldframe->numEntities ) {
			oldnum = 99999;
		} else {
			oldstate = &cl.parseEntities[
				(oldframe->parseEntitiesNum + oldindex) & (MAX_PARSE_ENTITIES-1)];
			oldnum = oldstate->number;
		}
	}

	while ( 1 ) {
		// read the entity index number
		newnum = MSG_ReadBits( msg, GENTITYNUM_BITS );

		if ( newnum == (MAX_GENTITIES-1) ) {
			break;
		}

		if ( msg->readcount > msg->cursize ) {
			Com_Error (ERR_DROP,"CL_ParsePacketEntities: end of message");
		}

		while ( oldnum < newnum ) {
			// one or more entities from the old packet are unchanged
			if ( cl_shownet->integer == 3 ) {
				Com_Printf ("%3i:  unchanged: %i\n", msg->readcount, oldnum);
			}
			CL_DeltaEntity( msg, newframe, oldnum, oldstate, qtrue );
			
			oldindex++;

			if ( oldindex >= oldframe->numEntities ) {
				oldnum = 99999;
			} else {
				oldstate = &cl.parseEntities[
					(oldframe->parseEntitiesNum + oldindex) & (MAX_PARSE_ENTITIES-1)];
				oldnum = oldstate->number;
			}
		}
		if (oldnum == newnum) {
			// delta from previous state
			if ( cl_shownet->integer == 3 ) {
				Com_Printf ("%3i:  delta: %i\n", msg->readcount, newnum);
			}
			CL_DeltaEntity( msg, newframe, newnum, oldstate, qfalse );

			oldindex++;

			if ( oldindex >= oldframe->numEntities ) {
				oldnum = 99999;
			} else {
				oldstate = &cl.parseEntities[
					(oldframe->parseEntitiesNum + oldindex) & (MAX_PARSE_ENTITIES-1)];
				oldnum = oldstate->number;
			}
			continue;
		}

		if ( oldnum > newnum ) {
			// delta from baseline
			if ( cl_shownet->integer == 3 ) {
				Com_Printf ("%3i:  baseline: %i\n", msg->readcount, newnum);
			}
			CL_DeltaEntity( msg, newframe, newnum, &cl.entityBaselines[newnum], qfalse );
			continue;
		}

	}

	// any remaining entities in the old frame are copied over
	while ( oldnum != 99999 ) {
		// one or more entities from the old packet are unchanged
		if ( cl_shownet->integer == 3 ) {
			Com_Printf ("%3i:  unchanged: %i\n", msg->readcount, oldnum);
		}
		CL_DeltaEntity( msg, newframe, oldnum, oldstate, qtrue );
		
		oldindex++;

		if ( oldindex >= oldframe->numEntities ) {
			oldnum = 99999;
		} else {
			oldstate = &cl.parseEntities[
				(oldframe->parseEntitiesNum + oldindex) & (MAX_PARSE_ENTITIES-1)];
			oldnum = oldstate->number;
		}
	}
}


/*
================
CL_ParseSnapshot

If the snapshot is parsed properly, it will be copied to
cl.snap and saved in cl.snapshots[].  If the snapshot is invalid
for any reason, no changes to the state will be made at all.
================
*/
void CL_ParseSnapshot( msg_t *msg ) {
	int			len;
	clSnapshot_t	*old;
	clSnapshot_t	newSnap;
	int			deltaNum;
	int			oldMessageNum;
	int			i, packetNum;

	// get the reliable sequence acknowledge number
	// NOTE: now sent with all server to client messages
	//clc.reliableAcknowledge = MSG_ReadLong( msg );

	// read in the new snapshot to a temporary buffer
	// we will only copy to cl.snap if it is valid
	Com_Memset (&newSnap, 0, sizeof(newSnap));

	// we will have read any new server commands in this
	// message before we got to svc_snapshot
	newSnap.serverCommandNum = clc.serverCommandSequence;

	newSnap.serverTime = MSG_ReadLong( msg );

	newSnap.messageNum = clc.serverMessageSequence;

	deltaNum = MSG_ReadByte( msg );
	if ( !deltaNum ) {
		newSnap.deltaNum = -1;
	} else {
		newSnap.deltaNum = newSnap.messageNum - deltaNum;
	}
	newSnap.snapFlags = MSG_ReadByte( msg );

	// If the frame is delta compressed from data that we
	// no longer have available, we must suck up the rest of
	// the frame, but not use it, then ask for a non-compressed
	// message 
	if ( newSnap.deltaNum <= 0 ) {
		newSnap.valid = qtrue;		// uncompressed frame
		old = NULL;
		clc.demowaiting = qfalse;	// we can start recording now
	} else {
		old = &cl.snapshots[newSnap.deltaNum & PACKET_MASK];
		if ( !old->valid ) {
			// should never happen
			Com_Printf ("Delta from invalid frame (not supposed to happen!).\n");
		} else if ( old->messageNum != newSnap.deltaNum ) {
			// The frame that the server did the delta from
			// is too old, so we can't reconstruct it properly.
			Com_Printf ("Delta frame too old.\n");
		} else if ( cl.parseEntitiesNum - old->parseEntitiesNum > MAX_PARSE_ENTITIES-128 ) {
			Com_Printf ("Delta parseEntitiesNum too old.\n");
		} else {
			newSnap.valid = qtrue;	// valid delta parse
		}
	}

	// read areamask
	len = MSG_ReadByte( msg );
	MSG_ReadData( msg, &newSnap.areamask, len);

	// read playerinfo
	SHOWNET( msg, "playerstate" );
	if ( old ) {
		MSG_ReadDeltaPlayerstate( msg, &old->ps, &newSnap.ps );
	} else {
		MSG_ReadDeltaPlayerstate( msg, NULL, &newSnap.ps );
	}

	// read packet entities
	SHOWNET( msg, "packet entities" );
	CL_ParsePacketEntities( msg, old, &newSnap );

	// if not valid, dump the entire thing now that it has
	// been properly read
	if ( !newSnap.valid ) {
		return;
	}

	// clear the valid flags of any snapshots between the last
	// received and this one, so if there was a dropped packet
	// it won't look like something valid to delta from next
	// time we wrap around in the buffer
	oldMessageNum = cl.snap.messageNum + 1;

	if ( newSnap.messageNum - oldMessageNum >= PACKET_BACKUP ) {
		oldMessageNum = newSnap.messageNum - ( PACKET_BACKUP - 1 );
	}
	for ( ; oldMessageNum < newSnap.messageNum ; oldMessageNum++ ) {
		cl.snapshots[oldMessageNum & PACKET_MASK].valid = qfalse;
	}

	// copy to the current good spot
	cl.snap = newSnap;
	cl.snap.ping = 999;
	// calculate ping time
	for ( i = 0 ; i < PACKET_BACKUP ; i++ ) {
		packetNum = ( clc.netchan.outgoingSequence - 1 - i ) & PACKET_MASK;
		if ( cl.snap.ps.commandTime >= cl.outPackets[ packetNum ].p_serverTime ) {
			cl.snap.ping = cls.realtime - cl.outPackets[ packetNum ].p_realtime;
			break;
		}
	}
	// save the frame off in the backup array for later delta comparisons
	cl.snapshots[cl.snap.messageNum & PACKET_MASK] = cl.snap;

	if (cl_shownet->integer == 3) {
		Com_Printf( "   snapshot:%i  delta:%i  ping:%i\n", cl.snap.messageNum,
		cl.snap.deltaNum, cl.snap.ping );
	}

	cl.newSnapshots = qtrue;
}


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

int cl_connectedToPureServer;

/*
==================
CL_SystemInfoChanged

The systeminfo configstring has been changed, so parse
new information out of it.  This will happen at every
gamestate, and possibly during gameplay.
==================
*/
void CL_SystemInfoChanged( void ) {
	char			*systemInfo;