multi.c

小型游戏引擎

			for(i=0;i<messleng;i++) bufptr[i] = syncbuf[i+1];
			if ((comrateoption&15) > 0)
			{
				i = getcrc(bufptr,messleng);
				updatecrc16(i,syncbuf[0]);
				if (((unsigned short)i) != ((long)syncbuf[syncbufleng-2])+((long)syncbuf[syncbufleng-1]<<8))
					bad |= 2;   //CRC error
			}

			syncbufleng = 0;
			if (bad != 0)
			{
					//Don't send reset again if outbufplc is not before incnt!
				if ((bad == 1) && ((((syncbuf[0]&127)-(*incnt))&127) >= 124))
				{
					bad = 0;
					continue;
				}

				bad = 0;
				if (comreset != 0) comreset--;
				if (((*comerror)|comreset) == 0)
				{
					*comerror = 2; comreset = 2;
					startcom();
				}
				continue;
			}

			*incnt = (((*incnt)+1)&127);
			if ((messleng > 0) && (bufptr[0] >= 200))  //200-255 are messages for engine's use only
				processreservedmessage(messleng,bufptr);

			comescape = 0; comreset = 0; *comerror = 0;
			return(messleng);
		}
		return(0);
	}
	else
	{
		if (*netinbufplc == *netinbufend) return(0);

		messleng = (short)netinbuf[*netinbufplc] + (((short)netinbuf[((*netinbufplc)+1)&(COMBUFSIZ-1)])<<8);
		for(i=0;i<messleng;i++)
			getmess[i] = netinbuf[((*netinbufplc)+i+2)&(COMBUFSIZ-1)];

		k = 0; *otherconnectindex = getmess[k++];

		for(totbad=0;totbad<NETBACKPACKETS;totbad++)   //Number of sub-packets per packet
		{
			toindex = getmess[k++];
			if (toindex == 0xfe)
			{
				netincnt[*otherconnectindex] = 0;  // (>= 200) && ( <= 254)
				submessleng = messleng-2;          // Submessleng not necessary
			}
			else
			{
				if (toindex == 0xff)
				{
					for(i=connecthead;i>=0;i=connectpoint2[i])
						if (i != *otherconnectindex)
						{
							if (i == myconnectindex) j = getmess[k];
							k++;
						}
				}
				else
					j = getmess[k++];

				if (j != netincnt[*otherconnectindex])
				{
					submessleng = (short)getmess[k]+(((short)getmess[k+1])<<8);
					k += submessleng+2;
					continue;
				}
				netincnt[*otherconnectindex]++;

				submessleng = (short)getmess[k]+(((short)getmess[k+1])<<8); k += 2;
			}
			for(i=0;i<submessleng;i++) bufptr[i] = getmess[k++];

			if (totbad == 0)
			{
					//Increment inbufplc only if first sub-message is read
				*netinbufplc = (((*netinbufplc)+messleng+2)&(COMBUFSIZ-1));
				if ((submessleng > 0) && (bufptr[0] >= 200)) //200-255 are messages for engine's use only
				{
					if (bufptr[0] >= 253)
					{
						processreservedmessage(submessleng,bufptr);
						if ((bufptr[0] == 253) || (bufptr[0] == 254)) return(0);
					}
					return(submessleng);
				}
			}
			if (*otherconnectindex == myconnectindex) return(0);
			return(submessleng);   //Got good packet
		}

		syncstate++;   //DON'T WANT TO GET HERE!!!
			//Increment inbufplc to make it not continuously screw up!
		*netinbufplc = (((*netinbufplc)+messleng+2)&(COMBUFSIZ-1));
	}
	return(0);
}

void initcrc(void)
{
	long i, j, k, a;

	for(j=0;j<256;j++)      //Calculate CRC table
	{
		k = (j<<8); a = 0;
		for(i=7;i>=0;i--)
		{
			if (((k^a)&0x8000) > 0)
				a = ((a<<1)&65535) ^ 0x1021;   //0x1021 = genpoly
			else
				a = ((a<<1)&65535);
			k = ((k<<1)&65535);
		}
		crctable[j] = (a&65535);
	}
}

long getcrc(char *buffer, short bufleng)
{
	long i, j;

	j = 0;
	for(i=bufleng-1;i>=0;i--) updatecrc16(j,buffer[i]);
	return(j&65535);
}

void installbicomhandlers(void)
{
#ifdef PLATFORM_DOS	
	union REGS r;
	struct SREGS sr;
	long lowp;
	void far *fh;

		//Get old protected mode handler
	r.x.eax = 0x3500+comvect;   /* DOS get vector (INT 0Ch) */
	sr.ds = sr.es = 0;
	int386x(0x21,&r,&r,&sr);
	orig_pm_sel = (unsigned short)sr.es;
	orig_pm_off = r.x.ebx;

		//Get old real mode handler
	r.x.eax = 0x0200;   /* DPMI get real mode vector */
	r.h.bl = comvect;
	int386(0x31,&r,&r);
	orig_rm_seg = (unsigned short)r.x.ecx;
	orig_rm_off = (unsigned short)r.x.edx;

		//Allocate memory in low memory to store real mode handler
	if ((lowp = convalloc32(COMCODEBYTES+(COMBUFSIZ<<1))) == 0)
		{ printf("Can't allocate conventional memory.\n"); exit; }

	inbufplc = (short *)(lowp+0);
	inbufend = (short *)(lowp+2);
	outbufplc = (short *)(lowp+4);
	outbufend = (short *)(lowp+6);
	comport = (short *)(lowp+8);
	comtype = (char *)(lowp+10);
	comerror = (char *)(lowp+11);
	comresend = (char *)(lowp+12);
	incnt = (char *)(lowp+13);
	inbuf = (char *)(lowp+COMCODEBYTES);
	outbuf = (char *)(lowp+COMCODEBYTES+COMBUFSIZ);

	memcpy((void *)lowp,(void *)rmbuffer,COMCODEBYTES);

		//Set new protected mode handler
	r.x.eax = 0x2500+comvect;   /* DOS set vector (INT 0Ch) */
	fh = (void far *)comhandler;
	r.x.edx = FP_OFF(fh);
	sr.ds = FP_SEG(fh);      //DS:EDX == &handler
	sr.es = 0;
	int386x(0x21,&r,&r,&sr);

		//Set new real mode handler (must be after setting protected mode)
	r.x.eax = 0x0201;
	r.h.bl = comvect;              //CX:DX == real mode &handler
	r.x.ecx = ((lowp>>4)&0xffff);  //D32realseg
	r.x.edx = COMCODEOFFS;         //D32realoff
	int386(0x31,&r,&r);
#else
	fprintf (stderr,"%s, line %d; installbicomhandlers() called\n",
		__FILE__, __LINE__);
#endif	
}

void uninstallbicomhandlers(void)
{
#ifdef PLATFORM_DOS	
	union REGS r;
	struct SREGS sr;

		//restore old protected mode handler
	r.x.eax = 0x2500+comvect;   /* DOS set vector (INT 0Ch) */
	r.x.edx = orig_pm_off;
	sr.ds = orig_pm_sel;    /* DS:EDX == &handler */
	sr.es = 0;
	int386x(0x21,&r,&r,&sr);

		//restore old real mode handler
	r.x.eax = 0x0201;   /* DPMI set real mode vector */
	r.h.bl = comvect;
	r.x.ecx = (unsigned long)orig_rm_seg;     //CX:DX == real mode &handler
	r.x.edx = (unsigned long)orig_rm_off;
	int386(0x31,&r,&r);
#else
	fprintf (stderr, "%s line %d; uninstallbicomhandlers() called\n",
		__FILE__, __LINE__);	
#endif	
}

void processreservedmessage(short tempbufleng, char *datempbuf)
{
	long i, j, k, daotherconnectnum, templong;

	switch(datempbuf[0])
	{
		//[253] (login, if myconnectnum's lowest, then respond with packet type 254)
		case 253:
			if (multioption < 5)
			{
				otherconnectnum = ((long)datempbuf[1])+(((long)datempbuf[2])<<8)+(((long)datempbuf[3])<<16)+(((long)datempbuf[4])<<24);

				datempbuf[0] = 254;
				sendpacket(-1,datempbuf,1);

				myconnectindex = 0;
				connecthead = 0; connectpoint2[0] = 1; connectpoint2[1] = -1;
				numplayers = 2;
			}
			else if (multioption >= 5)
			{
				daotherconnectnum = ((long)datempbuf[1])+((long)(datempbuf[2]<<8))+((long)(datempbuf[3]<<16))+((long)(datempbuf[4]<<24));
				if (daotherconnectnum != myconnectnum)
				{
					netinitconnection(daotherconnectnum,&datempbuf[5]);

					if ((myconnectindex == connecthead) || ((connectnum[connecthead] == daotherconnectnum) && (myconnectindex == connectpoint2[connecthead])))
					{
						datempbuf[0] = 254;
						j = 1;
						for(i=0;i<MAXPLAYERS;i++)
							if ((connectnum[i] != 0x7fffffff) && (connectnum[i] != daotherconnectnum))
							{
								datempbuf[j++] = (connectnum[i]&255);
								datempbuf[j++] = ((connectnum[i]>>8)&255);
								datempbuf[j++] = ((connectnum[i]>>16)&255);
								datempbuf[j++] = ((connectnum[i]>>24)&255);

								for(k=0;k<10;k++)
									datempbuf[j++] = compaddr[i][k];
							}

							//While this doesn't have to be a broadcast, sending
							//this info again makes good error correction
						sendpacket(-1,datempbuf,j);

						for(i=0;i<MAXPLAYERS;i++)
							if (connectnum[i] == daotherconnectnum)
							{
								sendpacket((short)i,datempbuf,j);
								break;
							}
					}
				}
			}
			break;
		case 254:  //[254][connectnum][connectnum]...(Packet type 253 response)
			if (multioption < 5)
			{
				myconnectindex = 1;
				connecthead = 0; connectpoint2[0] = 1; connectpoint2[1] = -1;
				numplayers = 2;
			}
			else if (multioption >= 5)
			{
				j = 1;
				while (j < tempbufleng)
				{
					templong = ((long)datempbuf[j])+((long)(datempbuf[j+1]<<8))+((long)(datempbuf[j+2]<<16))+((long)(datempbuf[j+3]<<24));
					netinitconnection(templong,&datempbuf[j+4]);
					j += 14;
				}
			}
			break;
		case 255:
			if (multioption >= 5)
				netuninitconnection(datempbuf[1]);
			break;
	}
}

void sendlogon(void)
{
	long i;
	char tempbuf[16];

	if (multioption <= 0)
		return;

	tempbuf[0] = 253;
	if (multioption < 5)
	{
		tempbuf[1] = kinp(0x40);
		tempbuf[2] = kinp(0x40);
		tempbuf[3] = kinp(0x40);
		tempbuf[4] = mypriority;
		myconnectnum = ((long)tempbuf[1])+(((long)tempbuf[2])<<8)+(((long)tempbuf[3])<<16)+(((long)mypriority)<<24);
		sendpacket(-1,tempbuf,5);
	}
	else
	{
		tempbuf[1] = (myconnectnum&255);
		tempbuf[2] = ((myconnectnum>>8)&255);
		tempbuf[3] = ((myconnectnum>>16)&255);
		tempbuf[4] = ((myconnectnum>>24)&255);
		for(i=0;i<10;i++)
			tempbuf[i+5] = mycompaddr[i];

		sendpacket(-1,tempbuf,15);
	}
}

void sendlogoff(void)
{
	char tempbuf[16];
	long i;

	if ((numplayers <= 1) || (multioption <= 0)) return;

	tempbuf[0] = 255;
	if (multioption < 5)
	{
		sendpacket(-1,tempbuf,1);
	}
	else
	{
		tempbuf[1] = myconnectindex;
		for(i=connecthead;i>=0;i=connectpoint2[i])
			if (i != myconnectindex)
				sendpacket(i,tempbuf,2);
	}
}

int getoutputcirclesize(void)
{
	if ((multioption >= 1) && (multioption <= 4))
	{
		startcom();
		return(((*outbufend)-(*outbufplc)+COMBUFSIZ)&(COMBUFSIZ-1));
	}
	return(0);
}

int setsocket(short newsocket)
{
	long i;

	if (multioption < 5)
	{
		socket = newsocket;
		return(0);
	}

	simulateint(0x7a,0L,(long)0x1,0L,(long)socket,0L,0L);                             //Closesocket

	socket = newsocket;

	simulateint(0x7a,0L,(long)0x1,0L,(long)socket,0L,0L);                             //Closesocket
	if ((simulateint(0x7a,(long)0xff,0L,0L,(long)socket,0L,0L)&255) != 0) return(-2); //Opensocket
	mycompaddr[10] = (socket&255);
	mycompaddr[11] = (socket>>8);
	ecbget[10] = (socket&255);
	ecbget[11] = (socket>>8);
	for(i=0;i<MAXPLAYERS;i++)
	{
		compaddr[i][10] = (socket&255);
		compaddr[i][11] = (socket>>8);
	}
	return(0);
}