C++ MSG_Bitstream函数代码示例

/*
===================
SV_ExecuteClientMessage

Parse a client packet
===================
*/
void SV_ExecuteClientMessage( client_t *cl, msg_t *msg ) {
	int			c;
	int			serverId;

	MSG_Bitstream(msg);

	serverId = MSG_ReadLong( msg );
	cl->messageAcknowledge = MSG_ReadLong( msg );

	if (cl->messageAcknowledge < 0) {
		// usually only hackers create messages like this
		// it is more annoying for them to let them hanging
		//SV_DropClient( cl, "illegible client message" );
		return;
	}

	cl->reliableAcknowledge = MSG_ReadLong( msg );

	// NOTE: when the client message is fux0red the acknowledgement numbers
	// can be out of range, this could cause the server to send thousands of server
	// commands which the server thinks are not yet acknowledged in SV_UpdateServerCommandsToClient
	if (cl->reliableAcknowledge < cl->reliableSequence - MAX_RELIABLE_COMMANDS) {
		// usually only hackers create messages like this
		// it is more annoying for them to let them hanging
		//SV_DropClient( cl, "illegible client message" );
		cl->reliableAcknowledge = cl->reliableSequence;
		return;
	}
	// if this is a usercmd from a previous gamestate,
	// ignore it or retransmit the current gamestate
	// 
	// if the client was downloading, let it stay at whatever serverId and
	// gamestate it was at.  This allows it to keep downloading even when
	// the gamestate changes.  After the download is finished, we'll
	// notice and send it a new game state
	if ( serverId != sv.serverId && !*cl->downloadName ) {
		if ( serverId == sv.restartedServerId ) {
			// they just haven't caught the map_restart yet
			return;
		}
		// if we can tell that the client has dropped the last
		// gamestate we sent them, resend it
		if ( cl->messageAcknowledge > cl->gamestateMessageNum ) {
			Com_DPrintf( "%s : dropped gamestate, resending\n", cl->name );
			SV_SendClientGameState( cl );
		}
		return;
	}

	// read optional clientCommand strings
	do {
		c = MSG_ReadByte( msg );
		if ( c == clc_EOF ) {
			break;
		}
		if ( c != clc_clientCommand ) {
			break;
		}
		if ( !SV_ClientCommand( cl, msg ) ) {
			return;	// we couldn't execute it because of the flood protection
		}
		if (cl->state == CS_ZOMBIE) {
			return;	// disconnect command
		}
	} while ( 1 );

	// read the usercmd_t
	if ( c == clc_move ) {
		SV_UserMove( cl, msg, qtrue );
	} else if ( c == clc_moveNoDelta ) {
		SV_UserMove( cl, msg, qfalse );
	} else if ( c != clc_EOF ) {
		Com_Printf( "WARNING: bad command byte for client %i\n", cl - svs.clients );
	}
//	if ( msg->readcount != msg->cursize ) {
//		Com_Printf( "WARNING: Junk at end of packet for client %i\n", cl - svs.clients );
//	}
}

/*
===================
SV_ExecuteClientMessage

Parse a client packet
===================
*/
void SV_ExecuteClientMessage( client_t *cl, msg_t *msg )
{
	int c;
	int serverId;

	MSG_Bitstream( msg );

	serverId = MSG_ReadLong( msg );
	cl->messageAcknowledge = MSG_ReadLong( msg );

	if ( cl->messageAcknowledge < 0 )
	{
		// usually only hackers create messages like this
		// it is more annoying for them to let them hanging
#ifndef NDEBUG
		SV_DropClient( cl, "DEBUG: illegible client message" );
#endif
		return;
	}

	cl->reliableAcknowledge = MSG_ReadLong( msg );

	// NOTE: when the client message is fux0red the acknowledgement numbers
	// can be out of range, this could cause the server to send thousands of server
	// commands which the server thinks are not yet acknowledged in SV_UpdateServerCommandsToClient
	if ( cl->reliableAcknowledge < cl->reliableSequence - MAX_RELIABLE_COMMANDS )
	{
		// usually only hackers create messages like this
		// it is more annoying for them to let them hanging
#ifndef NDEBUG
		SV_DropClient( cl, "DEBUG: illegible client message" );
#endif
		cl->reliableAcknowledge = cl->reliableSequence;
		return;
	}

	// if this is a usercmd from a previous gamestate,
	// ignore it or retransmit the current gamestate
	//
	// if the client was downloading, let it stay at whatever serverId and
	// gamestate it was at.  This allows it to keep downloading even when
	// the gamestate changes.  After the download is finished, we'll
	// notice and send it a new game state
	//
	// show_bug.cgi?id=536
	// don't drop as long as previous command was a nextdl, after a dl is done, downloadName is set back to ""
	// but we still need to read the next message to move to next download or send gamestate
	// I don't like this hack though, it must have been working fine at some point, suspecting the fix is somewhere else
	if ( serverId != sv.serverId && !*cl->downloadName && !strstr( cl->lastClientCommandString, "nextdl" ) )
	{
		if ( serverId >= sv.restartedServerId && serverId < sv.serverId )
		{
			// TTimo - use a comparison here to catch multiple map_restart
			// they just haven't caught the map_restart yet
			Log::Debug( "%s^7: ignoring pre map_restart / outdated client message", cl->name );
			return;
		}

		// if we can tell that the client has dropped the last
		// gamestate we sent them, resend it
		if ( cl->messageAcknowledge > cl->gamestateMessageNum )
		{
			Log::Debug( "%s^7: dropped gamestate, resending", cl->name );
			SV_SendClientGameState( cl );
		}

		// read optional clientCommand strings
		do
		{
			c = MSG_ReadByte( msg );

			if ( c == clc_EOF )
			{
				break;
			}

			if ( c != clc_clientCommand )
			{
				break;
			}

			if ( !SV_ClientCommand( cl, msg, true ) )
			{
				return; // we couldn't execute it because of the flood protection
			}

			if ( cl->state == clientState_t::CS_ZOMBIE )
			{
				return; // disconnect command
			}
		}
		while ( 1 );

//.........这里部分代码省略.........

/*
Start a server-side demo.

This does it all, create the file and adjust the demo-related
stuff in client_t.

This is mostly ripped from sv_client.c/SV_SendClientGameState
and cl_main.c/CL_Record_f.
*/
static void SVD_StartDemoFile(client_t *client, const char *path)
{
	int		i, len;
	entityState_t	*base, nullstate;
	msg_t		msg;
	byte		buffer[MAX_MSGLEN];
	fileHandle_t	file;
#ifdef USE_DEMO_FORMAT_42
	char		*s;
	int			v, size;
#endif

	Com_DPrintf("SVD_StartDemoFile\n");
	assert(!client->demo_recording);

	// create the demo file and write the necessary header
	file = FS_FOpenFileWrite(path);
	assert(file != 0);
	
	/* File_write_header_demo // ADD this fx */
	/* HOLBLIN  entete demo */ 
	#ifdef USE_DEMO_FORMAT_42
		//@Barbatos: get the mod version from the server
		s = Cvar_VariableString("g_modversion");
	
		size = strlen( s );
		len = LittleLong( size );
		FS_Write( &len, 4, file );
		FS_Write( s , size ,  file );
		
		v = LittleLong( PROTOCOL_VERSION );
		FS_Write ( &v, 4 , file );
		
		len = 0;
		len = LittleLong( len );
		FS_Write ( &len, 4 , file );
		FS_Write ( &len, 4 , file );
	#endif
	/* END HOLBLIN  entete demo */ 

	MSG_Init(&msg, buffer, sizeof(buffer));
	MSG_Bitstream(&msg); // XXX server code doesn't do this, client code does

	MSG_WriteLong(&msg, client->lastClientCommand); // TODO: or is it client->reliableSequence?

	MSG_WriteByte(&msg, svc_gamestate);
	MSG_WriteLong(&msg, client->reliableSequence);

	for (i = 0; i < MAX_CONFIGSTRINGS; i++) {
		if (sv.configstrings[i][0]) {
			MSG_WriteByte(&msg, svc_configstring);
			MSG_WriteShort(&msg, i);
			MSG_WriteBigString(&msg, sv.configstrings[i]);
		}
	}

	Com_Memset(&nullstate, 0, sizeof(nullstate));
	for (i = 0 ; i < MAX_GENTITIES; i++) {
		base = &sv.svEntities[i].baseline;
		if (!base->number) {
			continue;
		}
		MSG_WriteByte(&msg, svc_baseline);
		MSG_WriteDeltaEntity(&msg, &nullstate, base, qtrue);
	}

	MSG_WriteByte(&msg, svc_EOF);

	MSG_WriteLong(&msg, client - svs.clients);
	MSG_WriteLong(&msg, sv.checksumFeed);

	MSG_WriteByte(&msg, svc_EOF); // XXX server code doesn't do this, SV_Netchan_Transmit adds it!

	len = LittleLong(client->netchan.outgoingSequence-1);
	FS_Write(&len, 4, file);

	len = LittleLong (msg.cursize);
	FS_Write(&len, 4, file);
	FS_Write(msg.data, msg.cursize, file);

	#ifdef USE_DEMO_FORMAT_42
		// add size of packet in the end for backward play /* holblin */
		FS_Write(&len, 4, file);
	#endif

	FS_Flush(file);

	// adjust client_t to reflect demo started
	client->demo_recording = qtrue;
	client->demo_file = file;
	client->demo_waiting = qtrue;
//.........这里部分代码省略.........

/*
=====================
CL_ParseServerMessage
=====================
*/
void CL_ParseServerMessage( msg_t *msg ) {
	int			cmd;

	if ( cl_shownet->integer == 1 ) {
		Com_Printf ("%i ",msg->cursize);
	} else if ( cl_shownet->integer >= 2 ) {
		Com_Printf ("------------------\n");
	}

	MSG_Bitstream(msg);

	// get the reliable sequence acknowledge number
	clc.reliableAcknowledge = MSG_ReadLong( msg );
	// 
	if ( clc.reliableAcknowledge < clc.reliableSequence - MAX_RELIABLE_COMMANDS ) {
		clc.reliableAcknowledge = clc.reliableSequence;
	}

	//
	// parse the message
	//
	while ( 1 ) {
		if ( msg->readcount > msg->cursize ) {
			Com_Error (ERR_DROP,"CL_ParseServerMessage: read past end of server message");
			break;
		}

		cmd = MSG_ReadByte( msg );

		if (cmd == svc_EOF) {
			SHOWNET( msg, "END OF MESSAGE" );
			break;
		}

		if ( cl_shownet->integer >= 2 ) {
			if ( (cmd < 0) || (!svc_strings[cmd]) ) {
				Com_Printf( "%3i:BAD CMD %i\n", msg->readcount-1, cmd );
			} else {
				SHOWNET( msg, svc_strings[cmd] );
			}
		}
	
	// other commands
		switch ( cmd ) {
		default:
			Com_Error (ERR_DROP,"CL_ParseServerMessage: Illegible server message");
			break;			
		case svc_nop:
			break;
		case svc_serverCommand:
			CL_ParseCommandString( msg );
			break;
		case svc_gamestate:
			CL_ParseGamestate( msg );
			break;
		case svc_snapshot:
			CL_ParseSnapshot( msg );
			break;
		case svc_download:
			CL_ParseDownload( msg );
			break;
		case svc_voipSpeex:
#ifdef USE_VOIP
			CL_ParseVoip( msg, qtrue );
#endif
			break;
		case svc_voipOpus:
#ifdef USE_VOIP
			CL_ParseVoip( msg, !clc.voipEnabled );
#endif
			break;
		}
	}
}

/*
===================
CL_WritePacket

Create and send the command packet to the server
Including both the reliable commands and the usercmds

A client packet will contain something like:

4 sequence number
2 qport
4 serverid
4 acknowledged sequence number
4 clc.serverCommandSequence
<optional reliable commands>
1 clc_move or clc_moveNoDelta
1 command count
<count * usercmds>

===================
*/
void CL_WritePacket()
{
	msg_t     buf;
	byte      data[ MAX_MSGLEN ];
	int       i, j;
	usercmd_t *cmd, *oldcmd;
	usercmd_t nullcmd;
	int       packetNum;
	int       oldPacketNum;
	int       count;

	// don't send anything if playing back a demo
	if ( clc.demoplaying || cls.state == CA_CINEMATIC )
	{
		return;
	}

	memset( &nullcmd, 0, sizeof( nullcmd ) );
	oldcmd = &nullcmd;

	MSG_Init( &buf, data, sizeof( data ) );

	MSG_Bitstream( &buf );
	// write the current serverId so the server
	// can tell if this is from the current gameState
	MSG_WriteLong( &buf, cl.serverId );

	// write the last message we received, which can
	// be used for delta compression, and is also used
	// to tell if we dropped a gamestate
	MSG_WriteLong( &buf, clc.serverMessageSequence );

	// write the last reliable message we received
	MSG_WriteLong( &buf, clc.serverCommandSequence );

	// write any unacknowledged clientCommands
	// NOTE TTimo: if you verbose this, you will see that there are quite a few duplicates
	// typically several unacknowledged cp or userinfo commands stacked up
	for ( i = clc.reliableAcknowledge + 1; i <= clc.reliableSequence; i++ )
	{
		MSG_WriteByte( &buf, clc_clientCommand );
		MSG_WriteLong( &buf, i );
		MSG_WriteString( &buf, clc.reliableCommands[ i & ( MAX_RELIABLE_COMMANDS - 1 ) ] );
	}

	// we want to send all the usercmds that were generated in the last
	// few packet, so even if a couple packets are dropped in a row,
	// all the cmds will make it to the server
	if ( cl_packetdup->integer < 0 )
	{
		Cvar_Set( "cl_packetdup", "0" );
	}
	else if ( cl_packetdup->integer > 5 )
	{
		Cvar_Set( "cl_packetdup", "5" );
	}

	oldPacketNum = ( clc.netchan.outgoingSequence - 1 - cl_packetdup->integer ) & PACKET_MASK;
	count = cl.cmdNumber - cl.outPackets[ oldPacketNum ].p_cmdNumber;

	if ( count > MAX_PACKET_USERCMDS )
	{
		count = MAX_PACKET_USERCMDS;
		Com_Printf( "MAX_PACKET_USERCMDS" );
	}

#ifdef USE_VOIP

	if ( clc.voipOutgoingDataSize > 0 )
	{
		if ( ( clc.voipFlags & VOIP_SPATIAL ) || Com_IsVoipTarget( clc.voipTargets, sizeof( clc.voipTargets ), -1 ) )
		{
			MSG_WriteByte( &buf, clc_voip );
			MSG_WriteByte( &buf, clc.voipOutgoingGeneration );
			MSG_WriteLong( &buf, clc.voipOutgoingSequence );
			MSG_WriteByte( &buf, clc.voipOutgoingDataFrames );
			MSG_WriteData( &buf, clc.voipTargets, sizeof( clc.voipTargets ) );
			MSG_WriteByte( &buf, clc.voipFlags );
			MSG_WriteShort( &buf, clc.voipOutgoingDataSize );
//.........这里部分代码省略.........

/*
=====================
CL_ParseServerMessage
=====================
*/
void CL_ParseServerMessage(msg_t *msg)
{
	int cmd;

	if (cl_shownet->integer == 1)
	{
		Com_Printf("%i ", msg->cursize);
	}
	else if (cl_shownet->integer >= 2)
	{
		Com_Printf("------------------\n");
	}

	MSG_Bitstream(msg);

	// get the reliable sequence acknowledge number
	clc.reliableAcknowledge = MSG_ReadLong(msg);

	if (clc.reliableAcknowledge < clc.reliableSequence - MAX_RELIABLE_COMMANDS)
	{
		clc.reliableAcknowledge = clc.reliableSequence;
	}

	// parse the message
	while (1)
	{
		if (msg->readcount > msg->cursize)
		{
			Com_Error(ERR_DROP, "CL_ParseServerMessage: read past end of server message");
			break;
		}

		cmd = MSG_ReadByte(msg);

		if (cmd == svc_EOF)
		{
			SHOWNET(msg, "END OF MESSAGE");
			break;
		}

		if (cl_shownet->integer >= 2)
		{
			if (cmd < 0 || cmd > svc_EOF) // MSG_ReadByte might return -1 and we can't access our svc_strings array ...
			{
				Com_Printf("%3i:BAD BYTE %i\n", msg->readcount - 1, cmd); // -> ERR_DROP
			}
			else
			{
				if (!svc_strings[cmd])
				{
					Com_Printf("%3i:BAD CMD %i\n", msg->readcount - 1, cmd);
				}
				else
				{
					SHOWNET(msg, svc_strings[cmd]);
				}
			}
		}

		// other commands
		switch (cmd)
		{
		default:
			Com_Error(ERR_DROP, "CL_ParseServerMessage: Illegible server message %d", cmd);
			break;
		case svc_nop:
			break;
		case svc_serverCommand:
			CL_ParseCommandString(msg);
			break;
		case svc_gamestate:
			CL_ParseGamestate(msg);
			break;
		case svc_snapshot:
			CL_ParseSnapshot(msg);
			break;
		case svc_download:
			CL_ParseDownload(msg);
			break;
		}
	}

	CL_ParseBinaryMessage(msg);
}

/*
===================
CL_WritePacket

Create and send the command packet to the server
Including both the reliable commands and the usercmds

During normal gameplay, a client packet will contain something like:

4	sequence number
2	qport
4	serverid
4	acknowledged sequence number
4	clc.serverCommandSequence
<optional reliable commands>
1	clc_move or clc_moveNoDelta
1	command count
<count * usercmds>

===================
*/
void CL_WritePacket( void ) {
	msg_t		buf;
	byte		data[MAX_MSGLEN];
	int			i, j;
	usercmd_t	*cmd, *oldcmd;
	usercmd_t	nullcmd;
	int			packetNum;
	int			oldPacketNum;
	int			count, key;

	// don't send anything if playing back a demo
	if ( clc.demoplaying || cls.state == CA_CINEMATIC ) {
		return;
	}

	Com_Memset( &nullcmd, 0, sizeof(nullcmd) );
	oldcmd = &nullcmd;

	MSG_Init( &buf, data, sizeof(data) );

	MSG_Bitstream( &buf );
	// write the current serverId so the server
	// can tell if this is from the current gameState
	MSG_WriteLong( &buf, cl.serverId );

	// write the last message we received, which can
	// be used for delta compression, and is also used
	// to tell if we dropped a gamestate
	MSG_WriteLong( &buf, clc.serverMessageSequence );

	// write the last reliable message we received
	MSG_WriteLong( &buf, clc.serverCommandSequence );

	// write any unacknowledged clientCommands
	for ( i = clc.reliableAcknowledge + 1 ; i <= clc.reliableSequence ; i++ ) {
		MSG_WriteByte( &buf, clc_clientCommand );
		MSG_WriteLong( &buf, i );
		MSG_WriteString( &buf, clc.reliableCommands[ i & (MAX_RELIABLE_COMMANDS-1) ] );
	}

	// we want to send all the usercmds that were generated in the last
	// few packet, so even if a couple packets are dropped in a row,
	// all the cmds will make it to the server
	if ( cl_packetdup->integer < 0 ) {
		Cvar_Set( "cl_packetdup", "0" );
	} else if ( cl_packetdup->integer > 5 ) {
		Cvar_Set( "cl_packetdup", "5" );
	}
	oldPacketNum = (clc.netchan.outgoingSequence - 1 - cl_packetdup->integer) & PACKET_MASK;
	count = cl.cmdNumber - cl.outPackets[ oldPacketNum ].p_cmdNumber;
	if ( count > MAX_PACKET_USERCMDS ) {
		count = MAX_PACKET_USERCMDS;
		Com_Printf("MAX_PACKET_USERCMDS\n");
	}
	if ( count >= 1 ) {
		if ( cl_showSend->integer ) {
			Com_Printf( "(%i)", count );
		}

		// begin a client move command
		if ( cl_nodelta->integer || !cl.snap.valid
			|| clc.demowaiting
			|| clc.serverMessageSequence != cl.snap.messageNum ) {
			MSG_WriteByte (&buf, clc_moveNoDelta);
		} else {
			MSG_WriteByte (&buf, clc_move);
		}

		// write the command count
		MSG_WriteByte( &buf, count );

		// use the checksum feed in the key
		key = clc.checksumFeed;
		// also use the message acknowledge
		key ^= clc.serverMessageSequence;
		// also use the last acknowledged server command in the key
		key ^= Com_HashKey(clc.serverCommands[ clc.serverCommandSequence & (MAX_RELIABLE_COMMANDS-1) ], 32);

		// write all the commands, including the predicted command
//.........这里部分代码省略.........

//.........这里部分代码省略.........
			cl.parseEntitiesNum = parseEntitiesNumOrig;
			return qfalse;
		}

		buf.cursize = LittleLong(buf.cursize);
		if (buf.cursize == -1)
		{
			Com_FuncPrinf("buf.cursize == -1\n");
			FS_Seek(clc.demofile, origPosition, FS_SEEK_SET);
			clc.lastPacketTime  = lastPacketTimeOrig;
			cl.parseEntitiesNum = parseEntitiesNumOrig;
			return qfalse;
		}

		if (buf.cursize > buf.maxsize)
		{
			Com_FuncDrop("demoMsglen > MAX_MSGLEN");
			return qfalse;
		}

		r = FS_Read(buf.data, buf.cursize, clc.demofile);
		if (r != buf.cursize)
		{
			Com_FuncPrinf("Demo file was truncated.\n");
			FS_Seek(clc.demofile, origPosition, FS_SEEK_SET);
			clc.lastPacketTime  = lastPacketTimeOrig;
			cl.parseEntitiesNum = parseEntitiesNumOrig;
			return qfalse;
		}

		clc.lastPacketTime = cls.realtime;
		buf.readcount      = 0;

		MSG_Bitstream(&buf);
		// get the reliable sequence acknowledge number
		MSG_ReadLong(&buf);

		// parse the message
		while (qtrue)
		{
			if (buf.readcount > buf.cursize)
			{
				Com_FuncDrop("read past end of server message");
				return qfalse;
			}

			cmd = MSG_ReadByte(&buf);

			if (cmd == svc_EOF)
			{
				break;
			}
			success = qfalse;

			switch (cmd)
			{
			default:
				Com_FuncDrop("Illegible server message");
				return qfalse;
			case svc_nop:
				break;
			case svc_serverCommand:
				MSG_ReadLong(&buf);  // seq
				//s = MSG_ReadString(&buf);
				MSG_ReadString(&buf);
				break;

// Do very shallow parse of the demo (could be extended) just to get times and snapshot count
static void CL_ParseDemo(void)
{
	int tstart   = 0;
	int demofile = 0;

	// Reset our demo data
	memset(&di, 0, sizeof(di));

	// Parse start
	di.gameStartTime = -1;
	di.gameEndTime   = -1;
	FS_Seek(clc.demofile, 0, FS_SEEK_SET);
	tstart = Sys_Milliseconds();

	while (qtrue)
	{
		int   r;
		msg_t buf;
		msg_t *msg;
		byte  bufData[MAX_MSGLEN];
		int   s;
		int   cmd;

		di.demoPos = FS_FTell(clc.demofile);

		// get the sequence number
		r = FS_Read(&s, 4, clc.demofile);
		if (r != 4)
		{
			CL_DemoCompleted();
			return;
		}

		clc.serverMessageSequence = LittleLong(s);

		// init the message
		MSG_Init(&buf, bufData, sizeof(bufData));

		// get the length
		r = FS_Read(&buf.cursize, 4, clc.demofile);

		if (r != 4)
		{
			break;
		}

		buf.cursize = LittleLong(buf.cursize);
		if (buf.cursize == -1)
		{
			break;
		}

		if (buf.cursize > buf.maxsize)
		{
			Com_FuncPrinf("demoMsglen > MAX_MSGLEN");
			break;
		}

		r = FS_Read(buf.data, buf.cursize, clc.demofile);
		if (r != buf.cursize)
		{
			Com_FuncPrinf("Demo file was truncated.\n");
			break;
		}

		clc.lastPacketTime = cls.realtime;
		buf.readcount      = 0;

		// parse
		msg = &buf;
		MSG_Bitstream(msg);

		// get the reliable sequence acknowledge number
		clc.reliableAcknowledge = MSG_ReadLong(msg);

		if (clc.reliableAcknowledge < clc.reliableSequence - MAX_RELIABLE_COMMANDS)
		{
			clc.reliableAcknowledge = clc.reliableSequence;
		}

		// parse the message
		while (qtrue)
		{
			if (msg->readcount > msg->cursize)
			{
				Com_FuncDrop("read past end of server message");
				return;
			}

			cmd = MSG_ReadByte(msg);

			if (cmd == svc_EOF)
			{
				break;
			}

			// other commands
			switch (cmd)
			{
//.........这里部分代码省略.........

void CL_Record(const char *name)
{
	int           i;
	msg_t         buf;
	byte          bufData[MAX_MSGLEN];
	entityState_t *ent;
	entityState_t nullstate;
	char          *s;
	int           len;

	// open the demo file
	Com_FuncPrinf("Recording to %s.\n", name);
	clc.demofile = FS_FOpenFileWrite(name);
	if (!clc.demofile)
	{
		Com_FuncPrinf("ERROR: couldn't open.\n");
		return;
	}

	clc.demorecording = qtrue;
	Cvar_Set("cl_demorecording", "1");    // fretn
	Q_strncpyz(clc.demoName, demoName, sizeof(clc.demoName));
	Cvar_Set("cl_demofilename", clc.demoName);    // bani
	Cvar_Set("cl_demooffset", "0");    // bani

	// don't start saving messages until a non-delta compressed message is received
	clc.demowaiting = qtrue;

	// write out the gamestate message
	MSG_Init(&buf, bufData, sizeof(bufData));
	MSG_Bitstream(&buf);

	// NOTE: all server->client messages now acknowledge
	MSG_WriteLong(&buf, clc.reliableSequence);

	MSG_WriteByte(&buf, svc_gamestate);
	MSG_WriteLong(&buf, clc.serverCommandSequence);

	// configstrings
	for (i = 0; i < MAX_CONFIGSTRINGS; i++)
	{
		if (!cl.gameState.stringOffsets[i])
		{
			continue;
		}
		s = cl.gameState.stringData + cl.gameState.stringOffsets[i];
		MSG_WriteByte(&buf, svc_configstring);
		MSG_WriteShort(&buf, i);
		MSG_WriteBigString(&buf, s);
	}

	// baselines
	memset(&nullstate, 0, sizeof(nullstate));
	for (i = 0; i < MAX_GENTITIES; i++)
	{
		ent = &cl.entityBaselines[i];
		if (!ent->number)
		{
			continue;
		}
		MSG_WriteByte(&buf, svc_baseline);
		MSG_WriteDeltaEntity(&buf, &nullstate, ent, qtrue);
	}

	MSG_WriteByte(&buf, svc_EOF);

	// finished writing the gamestate stuff

	// write the client num
	MSG_WriteLong(&buf, clc.clientNum);
	// write the checksum feed
	MSG_WriteLong(&buf, clc.checksumFeed);

	// finished writing the client packet
	MSG_WriteByte(&buf, svc_EOF);

	// write it to the demo file
	len = LittleLong(clc.serverMessageSequence - 1);
	FS_Write(&len, 4, clc.demofile);

	len = LittleLong(buf.cursize);
	FS_Write(&len, 4, clc.demofile);
	FS_Write(buf.data, buf.cursize, clc.demofile);

	// the rest of the demo file will be copied from net messages
}

//.........这里部分代码省略.........
						newnum = MSG_ReadBits( &oldMsg, GENTITYNUM_BITS );
					} else if (oldnum > newnum) {
						MSG_ReadDeltaEntity( &oldMsg, &convert->entityBaselines[newnum], newstate , newnum );
						if ( newstate->number != MAX_GENTITIES-1)
							workFrame->entityData[ newstate->number ] = 1;
						newnum = MSG_ReadBits( &oldMsg, GENTITYNUM_BITS );
					}
					if (newstate->number == MAX_GENTITIES-1)
						continue;
					parseEntitiesNum++;
					parseEntitiesNum &= (MAX_PARSE_ENTITIES-1);
					newSnap->numEntities++;
				}}
				/* Stop processing this further since it's an invalid snap due to lack of delta data */
				if (!newSnap->valid)
					break;

				/* Skipped snapshots will be set invalid in the circular buffer */
				if ( newSnap->messageNum - convert->lastMessageNum >= PACKET_BACKUP ) {
					convert->lastMessageNum = newSnap->messageNum - ( PACKET_BACKUP - 1 );
				}
				for ( ; convert->lastMessageNum < newSnap->messageNum ; convert->lastMessageNum++ ) {
					convert->snapshots[convert->lastMessageNum & PACKET_MASK].valid = qfalse;
				}
				convert->lastMessageNum = newSnap->messageNum + 1;

				/* compress the frame into the new format */
				if (nextTime > oldTime) {
					demoFrame_t *cleanFrame;
					int writeIndex;
					for (temp = 0;temp<newSnap->numEntities;temp++) {
						int p = (newSnap->parseEntitiesNum+temp) & (MAX_PARSE_ENTITIES-1);
						entityState_t *newState = &convert->parseEntities[p];
						workFrame->entities[newState->number] = *newState;
					}
					workFrame->clientData[clientNum] = 1;
					workFrame->clients[clientNum] = newSnap->ps;
					workFrame->serverTime = nextTime;

					/* Which frame from the cache to save */
					writeIndex = convert->frameIndex - (DEMOCONVERTFRAMES/2);
					if (writeIndex >= 0) {
						const demoFrame_t *newFrame;
						msg_t writeMsg;
						// init the message
						MSG_Init( &writeMsg, demoBuffer, sizeof (demoBuffer));
						MSG_Clear( &writeMsg );
						MSG_Bitstream( &writeMsg );
						newFrame = &convert->frames[ writeIndex  % DEMOCONVERTFRAMES];
						if ( smoothen )
							demoFrameInterpolate( convert->frames, DEMOCONVERTFRAMES, writeIndex );
						if ( nextTime > fullTime || writeIndex <= 0 ) {
							/* Plan the next time for a full write */
							fullTime = nextTime + 2000;
							demoFramePack( &writeMsg, newFrame, 0 );
						} else {
							const demoFrame_t *oldFrame = &convert->frames[ ( writeIndex -1 ) % DEMOCONVERTFRAMES];
							demoFramePack( &writeMsg, newFrame, oldFrame );
						}
						/* Write away the new data in the msg queue */
						temp = LittleLong( writeMsg.cursize );
						FS_Write (&temp, 4, newHandle );
						FS_Write ( writeMsg.data , writeMsg.cursize, newHandle );
					}

					/* Clean up the upcoming frame for all new changes */
					convert->frameIndex++;
					cleanFrame = &convert->frames[ convert->frameIndex % DEMOCONVERTFRAMES];
					cleanFrame->serverTime = 0;
					for (temp = 0;temp<MAX_GENTITIES;temp++)
						cleanFrame->entities[temp].number = MAX_GENTITIES-1;
					Com_Memset( cleanFrame->clientData, 0, sizeof ( cleanFrame->clientData ));
					Com_Memcpy( cleanFrame->string.data, workFrame->string.data, workFrame->string.used );
					Com_Memcpy( cleanFrame->string.offsets, workFrame->string.offsets, sizeof( workFrame->string.offsets ));
					cleanFrame->string.used = workFrame->string.used;
					cleanFrame->commandUsed = 0;
					/* keep track of this last frame's time */
					oldTime = nextTime;
				}
				break;
			case svc_download:
				// read block number
				temp = MSG_ReadShort ( &oldMsg );
				if (!temp)	//0 block, read file size
					MSG_ReadLong( &oldMsg );
				// read block size
				temp = MSG_ReadShort ( &oldMsg );
				// read the data block
				for ( ;temp>0;temp--)
					MSG_ReadByte( &oldMsg );
				break;
			}
		}
	}
conversionerror:
	FS_FCloseFile( oldHandle );
	FS_FCloseFile( newHandle );
	Z_Free( convert );
	return;
}

/*
=====================
CL_ParseServerMessage
=====================
*/
void CL_ParseServerMessage( msg_t *msg ) {
	int			cmd;

	if ( cl_shownet->integer == 1 ) {
		Com_Printf ("%i ",msg->cursize);
	} else if ( cl_shownet->integer >= 2 ) {
		Com_Printf ("------------------\n");
	}

	MSG_Bitstream(msg);

	// get the reliable sequence acknowledge number
	clc.reliableAcknowledge = MSG_ReadLong( msg );
	// 
	if ( clc.reliableAcknowledge < clc.reliableSequence - MAX_RELIABLE_COMMANDS ) {
		clc.reliableAcknowledge = clc.reliableSequence;
	}

	//
	// parse the message
	//
	while ( 1 ) {
		if ( msg->readcount > msg->cursize ) {
			Com_Error (ERR_DROP,"CL_ParseServerMessage: read past end of server message");
			break;
		}

		cmd = MSG_ReadByte( msg );

		if ( cmd == svc_EOF) {
			SHOWNET( msg, "END OF MESSAGE" );
			break;
		}

		if ( cl_shownet->integer >= 2 ) {
			if ( !svc_strings[cmd] ) {
				Com_Printf( "%3i:BAD CMD %i\n", msg->readcount-1, cmd );
			} else {
				SHOWNET( msg, svc_strings[cmd] );
			}
		}
	
	// other commands
		switch ( cmd ) {
		default:
			Com_Error (ERR_DROP,"CL_ParseServerMessage: Illegible server message\n");
			break;			
		case svc_nop:
			break;
		case svc_serverCommand:
			CL_ParseCommandString( msg );
			break;
		case svc_gamestate:
			CL_ParseGamestate( msg );
			break;
		case svc_snapshot:
			CL_ParseSnapshot( msg );
			break;
		case svc_download:
			CL_ParseDownload( msg );
			break;
		case svc_lua:
			//Make Lua VMCall Here. -Hxrmn
			CL_SetLuaMessage(msg);
			VM_Call (cgvm, CG_LUA_MSG);
			break;
		}
	}
}

/*
=====================
CL_ParseServerMessage
=====================
*/
void CL_ParseServerMessage( msg_t *msg )
{
	int cmd;
//	msg_t           msgback;

//	msgback = *msg;

	if ( cl_shownet->integer == 1 )
	{
		Com_Printf("%i ", msg->cursize );
	}
	else if ( cl_shownet->integer >= 2 )
	{
		Com_Printf( "------------------\n" );
	}

	MSG_Bitstream( msg );

	// get the reliable sequence acknowledge number
	clc.reliableAcknowledge = MSG_ReadLong( msg );

	//
	if ( clc.reliableAcknowledge < clc.reliableSequence - MAX_RELIABLE_COMMANDS )
	{
		clc.reliableAcknowledge = clc.reliableSequence;
	}

	//
	// parse the message
	//
	while ( 1 )
	{
		if ( msg->readcount > msg->cursize )
		{
			Com_Error( ERR_DROP, "CL_ParseServerMessage: read past end of server message" );
		}

		cmd = MSG_ReadByte( msg );

		// See if this is an extension command after the EOF, which means we
		//  got data that a legacy client should ignore.
		if ( ( cmd == svc_EOF ) && ( MSG_LookaheadByte( msg ) == svc_extension ) )
		{
			SHOWNET( msg, "EXTENSION" );
			MSG_ReadByte( msg );  // throw the svc_extension byte away.
			cmd = MSG_ReadByte( msg );  // something legacy clients can't do!

			// sometimes you get a svc_extension at end of stream...dangling
			//  bits in the huffman decoder giving a bogus value?
			if ( cmd == -1 )
			{
				cmd = svc_EOF;
			}
		}

		if ( cmd == svc_EOF )
		{
			SHOWNET( msg, "END OF MESSAGE" );
			break;
		}

		if ( cl_shownet->integer >= 2 )
		{
			if ( !svc_strings[ cmd ] )
			{
				Com_Printf( "%3i:BAD CMD %i\n", msg->readcount - 1, cmd );
			}
			else
			{
				SHOWNET( msg, svc_strings[ cmd ] );
			}
		}

		// other commands
		switch ( cmd )
		{
			default:
				Com_Error( ERR_DROP, "CL_ParseServerMessage: Illegible server message %d", cmd );

			case svc_nop:
				break;

			case svc_serverCommand:
				CL_ParseCommandString( msg );
				break;

			case svc_gamestate:
				CL_ParseGamestate( msg );
				break;

			case svc_snapshot:
				CL_ParseSnapshot( msg );
				break;

			case svc_download:
//.........这里部分代码省略.........

void demoCutWriteDeltaSnapshot(int firstServerCommand, fileHandle_t f, qboolean forceNonDelta, clientConnection_t *clcCut, clientActive_t *clCut) {
	msg_t			msgImpl, *msg = &msgImpl;
	byte			msgData[MAX_MSGLEN];
	clSnapshot_t	*frame, *oldframe;
	int				lastframe = 0;
	int				snapFlags;
	MSG_Init(msg, msgData, sizeof(msgData));
	MSG_Bitstream(msg);
	MSG_WriteLong(msg, clcCut->reliableSequence);
	// copy over any commands
	for (int serverCommand = firstServerCommand; serverCommand <= clcCut->serverCommandSequence; serverCommand++) {
		char *command = clcCut->serverCommands[serverCommand & (MAX_RELIABLE_COMMANDS - 1)];
		MSG_WriteByte(msg, svc_serverCommand);
		MSG_WriteLong(msg, serverCommand/* + serverCommandOffset*/);
		MSG_WriteString(msg, command);
	}
	// this is the snapshot we are creating
	frame = &clCut->snap;
	if (clCut->snap.messageNum > 0 && !forceNonDelta) {
		lastframe = 1;
		oldframe = &clCut->snapshots[(clCut->snap.messageNum - 1) & PACKET_MASK]; // 1 frame previous
		if (!oldframe->valid) {
			// not yet set
			lastframe = 0;
			oldframe = NULL;
		}
	} else {
		lastframe = 0;
		oldframe = NULL;
	}
	MSG_WriteByte(msg, svc_snapshot);
	// send over the current server time so the client can drift
	// its view of time to try to match
	MSG_WriteLong(msg, frame->serverTime);
	// what we are delta'ing from
	MSG_WriteByte(msg, lastframe);
	snapFlags = frame->snapFlags;
	MSG_WriteByte(msg, snapFlags);
	// send over the areabits
	MSG_WriteByte(msg, sizeof(frame->areamask));
	MSG_WriteData(msg, frame->areamask, sizeof(frame->areamask));
	// delta encode the playerstate
	if (oldframe) {
#ifdef _ONEBIT_COMBO
		MSG_WriteDeltaPlayerstate(msg, &oldframe->ps, &frame->ps, frame->pDeltaOneBit, frame->pDeltaNumBit);
#else
		MSG_WriteDeltaPlayerstate(msg, &oldframe->ps, &frame->ps);
#endif
		if (frame->ps.m_iVehicleNum) {
		//then write the vehicle's playerstate too
			if (!oldframe->ps.m_iVehicleNum) {
			//if last frame didn't have vehicle, then the old vps isn't gonna delta
			//properly (because our vps on the client could be anything)
#ifdef _ONEBIT_COMBO
				MSG_WriteDeltaPlayerstate(msg, NULL, &frame->vps, NULL, NULL, qtrue);
#else
				MSG_WriteDeltaPlayerstate(msg, NULL, &frame->vps, qtrue);
#endif
			} else {
#ifdef _ONEBIT_COMBO
				MSG_WriteDeltaPlayerstate(msg, &oldframe->vps, &frame->vps, frame->pDeltaOneBitVeh, frame->pDeltaNumBitVeh, qtrue);
#else
				MSG_WriteDeltaPlayerstate(msg, &oldframe->vps, &frame->vps, qtrue);
#endif
			}
		}
	} else {
#ifdef _ONEBIT_COMBO
		MSG_WriteDeltaPlayerstate(msg, NULL, &frame->ps, NULL, NULL);
#else
		MSG_WriteDeltaPlayerstate(msg, NULL, &frame->ps);
#endif
		if (frame->ps.m_iVehicleNum) {
		//then write the vehicle's playerstate too
#ifdef _ONEBIT_COMBO
			MSG_WriteDeltaPlayerstate(msg, NULL, &frame->vps, NULL, NULL, qtrue);
#else
			MSG_WriteDeltaPlayerstate(msg, NULL, &frame->vps, qtrue);
#endif
		}
	}
	// delta encode the entities
	demoCutEmitPacketEntities(oldframe, frame, msg, clCut);
	MSG_WriteByte(msg, svc_EOF);
	demoCutWriteDemoMessage(msg, f, clcCut);
}

/*
Start a server-side demo.

This does it all, create the file and adjust the demo-related
stuff in client_t.

This is mostly ripped from sv_client.c/SV_SendClientGameState
and cl_main.c/CL_Record_f.
*/
static void SVD_StartDemoFile(client_t *client, const char *path)
{
        int             i, len;
        entityState_t   *base, nullstate;
        msg_t           msg;
        byte            buffer[MAX_MSGLEN];
        fileHandle_t    file;

        Com_DPrintf("SVD_StartDemoFile\n");
        assert(!client->demo_recording);

        // create the demo file and write the necessary header
        file = FS_FOpenFileWrite(path);
        assert(file != 0);

        MSG_Init(&msg, buffer, sizeof(buffer));
        MSG_Bitstream(&msg); // XXX server code doesn't do this, client code does

        MSG_WriteLong(&msg, client->lastClientCommand); // TODO: or is it client->reliableSequence?

        MSG_WriteByte(&msg, svc_gamestate);
        MSG_WriteLong(&msg, client->reliableSequence);

        for (i = 0; i < MAX_CONFIGSTRINGS; i++) {
                if (sv.configstrings[i][0]) {
                        MSG_WriteByte(&msg, svc_configstring);
                        MSG_WriteShort(&msg, i);
                        MSG_WriteBigString(&msg, sv.configstrings[i]);
                }
        }

        Com_Memset(&nullstate, 0, sizeof(nullstate));
        for (i = 0 ; i < MAX_GENTITIES; i++) {
                base = &sv.svEntities[i].baseline;
                if (!base->number) {
                        continue;
                }
                MSG_WriteByte(&msg, svc_baseline);
                MSG_WriteDeltaEntity(&msg, &nullstate, base, qtrue);
        }

        MSG_WriteByte(&msg, svc_EOF);

        MSG_WriteLong(&msg, client - svs.clients);
        MSG_WriteLong(&msg, sv.checksumFeed);

        MSG_WriteByte(&msg, svc_EOF); // XXX server code doesn't do this, SV_Netchan_Transmit adds it!

        len = LittleLong(client->netchan.outgoingSequence-1);
        FS_Write(&len, 4, file);

        len = LittleLong (msg.cursize);
        FS_Write(&len, 4, file);
        FS_Write(msg.data, msg.cursize, file);

        FS_Flush(file);

        // adjust client_t to reflect demo started
        client->demo_recording = qtrue;
        client->demo_file = file;
        client->demo_waiting = qtrue;
        client->demo_backoff = 1;
        client->demo_deltas = 0;
}