zmodem.c

一个通讯程序源码

			case GOTCRCG:
			case GOTCRCQ:
			case GOTCRCW:
				crc = updcrc(((d=c)&0377),crc);
				if((c = zdlread()) & ~0377)
					goto crcfoo;
				crc = updcrc(c,crc);
				if((c = zdlread()) & ~0377)
					goto crcfoo;
				crc = updcrc(c,crc);
				if(crc & 0xFFFF)
				{
					report_str(badcrc,0);
					report_rx_ind(0);
					return(ERROR);
				}
				Rxcount = length - (end - buf);
				report_rxblklen(Rxcount);
				sprintf(s128,
#ifdef SHOW_ZHDR_TYPE
					"D16 %s %d",
#else
					"data %s %d",
#endif
					Zendnames[d-GOTCRCE&3],Rxcount);
				report_last_rxhdr(s128,0);
				report_rx_ind(0);
				return(d);
			case GOTCAN:
				report_str("Sender Cancelled",1);
				report_rx_ind(0);
				return(ZCAN);
			case TIMEOUT:
				report_str("TIMEOUT",0);
				report_rx_ind(0);
				return(c);
			default:
				report_str("Bad data subpacket",0);
				report_rx_ind(0);
				return(c);
			}
		}
		*buf++ = c;
		crc = updcrc(c,crc);
	}
	report_str("Data subpacket too long",0);
	report_rx_ind(0);
	return(ERROR);
}


/*
 * Read a ZMODEM header to hdr,either binary or hex.
 *  eflag controls local display of non zmodem characters:
 *	0:  no display
 *	1:  display printing characters only
 *	2:  display all non ZMODEM characters
 *  On success,set Zmodem to 1,set Rxpos and return type of header.
 *   Otherwise return negative on error.
 *   Return ERROR instantly if ZCRCW sequence,for fast error recovery.
 */
int
zgethdr(hdr,eflag)
char *hdr;
int eflag;
{
register int c,n,cancount;
#ifdef SHOW_ZHDR_TYPE
char *hdrtyp = "?";
#endif

	report_rx_ind(1);
	n = Zrwindow + Baudrate;	/* Max bytes before start of frame */
	Rxframeind = Rxtype = 0;

startover:
	cancount = 5;
again:
	/* Return immediate ERROR if ZCRCW sequence seen */
	switch(c = readline(Rxtimeout))
	{
	case RCDO:
	case TIMEOUT:
		goto fifi;
	case CAN:
gotcan:
		if(--cancount <= 0)
		{
			c = ZCAN; 
			goto fifi;
		}
		switch(c = readline(1))
		{
		case TIMEOUT:
			goto again;
		case ZCRCW:
			c = ERROR;
			/* **** FALL THRU TO **** */
		case RCDO:
			goto fifi;
		default:
			break;
		case CAN:
			if(--cancount <= 0)
			{
				c = ZCAN; 
				goto fifi;
			}
			goto again;
		}
		/* **** FALL THRU TO **** */
	default:
agn2:
		if( --n == 0)
		{
			report_str("Garbage count exceeded",1);
			report_last_rxhdr("Noise",0);
			report_rx_ind(0);
			return(ERROR);
		}
		goto startover;
	case ZPAD|0200:		/* This is what we want. */
	case ZPAD:		/* This is what we want. */
		evenp = c & 0200;
		break;
	}
	cancount = 5;
splat:
	switch(c = noxrd7())
	{
	case ZPAD:
		goto splat;
	case RCDO:
	case TIMEOUT:
		goto fifi;
	default:
		goto agn2;
	case ZDLE:		/* This is what we want. */
		break;
	}

	switch(c = noxrd7())
	{
	case RCDO:
	case TIMEOUT:
		goto fifi;
	case ZBIN:
		Rxframeind = ZBIN;  
		Crc32 = FALSE;
		c =  zrbhdr(hdr);
		break;
	case ZBIN32:
		Crc32 = Rxframeind = ZBIN32;
		c =  zrbhdr32(hdr);
		break;
	case ZHEX:
		Rxframeind = ZHEX;  
		Crc32 = FALSE;
		c =  zrhhdr(hdr);
		break;
	case CAN:
		goto gotcan;
	default:
		goto agn2;
	}
	Rxpos = hdr[ZP3] & 0377;
	Rxpos = (Rxpos<<8) + (hdr[ZP2] & 0377);
	Rxpos = (Rxpos<<8) + (hdr[ZP1] & 0377);
	Rxpos = (Rxpos<<8) + (hdr[ZP0] & 0377);
fifi:
	switch(c)
	{
	case GOTCAN:
		c = ZCAN;
		/* **** FALL THRU TO **** */
	case ZNAK:
	case ZCAN:
	case ERROR:
	case TIMEOUT:
	case RCDO:
		sprintf(s128,"Got %s",frametypes[c+FTOFFSET]);
		report_str(s128,0);
		/* **** FALL THRU TO **** */
	default:
#ifdef SHOW_ZHDR_TYPE
		switch(Rxframeind)
		{
		case ZBIN:		hdrtyp = "B16"; break;
		case ZBIN32:	hdrtyp = "B32"; break;
		case ZHEX:		hdrtyp = "HEX"; break;
		}
		if(c >= -3 && c <= FRTYPES)
			sprintf(s128,"%s %s %ld",hdrtyp,frametypes[c+FTOFFSET],Rxpos);
		else
			sprintf(s128,"%s 0x%02x? %ld",hdrtyp,c,Rxpos);
#else
		if(c >= -3 && c <= FRTYPES)
			sprintf(s128,"hdr %s %ld",frametypes[c+FTOFFSET],Rxpos);
		else
			sprintf(s128,"hdr 0x%02x? %ld",c,Rxpos);
#endif
		report_last_rxhdr(s128,0);
	}
	report_rx_ind(0);
	return(c);
}

/* Receive a binary style header (type and position) */
int
zrbhdr(hdr)
register char *hdr;
{
	register int c,n;
	register unsigned short crc;

	if((c = zdlread()) & ~0377)
		return(c);
	Rxtype = c;
	crc = updcrc(c,0);

	for(n=4; --n >= 0; ++hdr)
	{
		if((c = zdlread()) & ~0377)
			return(c);
		crc = updcrc(c,crc);
		*hdr = c;
	}
	if((c = zdlread()) & ~0377)
		return(c);
	crc = updcrc(c,crc);
	if((c = zdlread()) & ~0377)
		return(c);
	crc = updcrc(c,crc);
	if(crc & 0xFFFF)
	{
		if(evenp)
			report_str(masked,1);
		report_str(badcrc,0);
		return(ERROR);
	}
#if defined(ZMODEM)
	Protocol = ZMODEM;
#endif
	Zmodem = 1;
	return(Rxtype);
}

/* Receive a binary style header (type and position) with 32 bit FCS */
int
zrbhdr32(hdr)
register char *hdr;
{
	register int c,n;
	register UNSL long crc;

	if((c = zdlread()) & ~0377)
		return(c);
	Rxtype = c;
	crc = 0xFFFFFFFFL; 
	crc = UPDC32(c,crc);

	for(n=4; --n >= 0; ++hdr)
	{
		if((c = zdlread()) & ~0377)
			return(c);
		crc = UPDC32(c,crc);
		*hdr = c;
	}
	for(n=4; --n >= 0;)
	{
		if((c = zdlread()) & ~0377)
			return(c);
		crc = UPDC32(c,crc);
	}
	if(crc != 0xDEBB20E3)
	{
		if(evenp)
			report_str(masked,1);
		report_str(badcrc,0);
		return(ERROR);
	}
#if defined(ZMODEM)
	Protocol = ZMODEM;
#endif
	Zmodem = 1;
	return(Rxtype);
}


/* Receive a hex style header (type and position) */
int
zrhhdr(hdr)
char *hdr;
{
	register int c;
	register unsigned short crc;
	register int n;

	if((c = zgethex()) < 0)
		return(c);
	Rxtype = c;
	crc = updcrc(c,0);

	for(n=4; --n >= 0; ++hdr)
	{
		if((c = zgethex()) < 0)
			return(c);
		crc = updcrc(c,crc);
		*hdr = c;
	}
	if((c = zgethex()) < 0)
		return(c);
	crc = updcrc(c,crc);
	if((c = zgethex()) < 0)
		return(c);
	crc = updcrc(c,crc);
	if(crc & 0xFFFF)
	{
		report_str(badcrc,0); 
		return(ERROR);
	}
	if(readline(1) == '\r')	/* Throw away possible cr/lf */
		readline(1);
#if defined(ZMODEM)
	Protocol = ZMODEM;
#endif
	Zmodem = 1; 
	return(Rxtype);
}

/* Decode two lower case hex digits into an 8 bit byte value */
int
zgeth1()
{
	register int c,n;

	if((c = noxrd7()) < 0)
		return(c);
	n = c - '0';
	if(n > 9)
		n -= ('a' - ':');
	if(n & ~0xF)
		return(ERROR);
	if((c = noxrd7()) < 0)
		return(c);
	c -= '0';
	if(c > 9)
		c -= ('a' - ':');
	if(c & ~0xF)
		return(ERROR);
	c += (n<<4);
	return(c);
}

int
zgethex()
{
	return(zgeth1());
}


/*
 * Read a byte,checking for ZMODEM escape encoding
 *  including CAN*5 which represents a quick abort
 */
int
zdlread()
{
	register int c;

again:
	/* Quick check for non control characters */
	if((c = readline(Rxtimeout)) & 0140)
		return(c);
	switch(c)
	{
	case ZDLE:
		break;
	case 023:
	case 0223:
	case 021:
	case 0221:
		goto again;
	default:
		if(Zctlesc && !(c & 0140))
		{
			goto again;
		}
		return(c);
	}
again2:
	if((c = readline(Rxtimeout)) < 0)
		return(c);
	if(c == CAN && (c = readline(Rxtimeout)) < 0)
		return(c);
	if(c == CAN && (c = readline(Rxtimeout)) < 0)
		return(c);
	if(c == CAN && (c = readline(Rxtimeout)) < 0)
		return(c);
	switch(c)
	{
	case CAN:
		return(GOTCAN);
	case ZCRCE:
	case ZCRCG:
	case ZCRCQ:
	case ZCRCW:
		return(c | GOTOR);
	case ZRUB0:
		return(0177);
	case ZRUB1:
		return(0377);
	case 023:
	case 0223:
	case 021:
	case 0221:
		goto again2;
	default:
		if(Zctlesc && ! (c & 0140))
		{
			goto again2;
		}
		if((c & 0140) ==  0100)
			return(c ^ 0100);
		break;
	}
	sprintf(s128,"Bad escape sequence %x",c);
	report_str(s128,0);
	return(ERROR);
}

/*
 * Read a character from the modem line with timeout.
 *  Eat parity,XON and XOFF characters.
 */
int
noxrd7()
{
	register int c;

	for(;;)
	{
		if((c = readline(Rxtimeout)) < 0)
			return(c);
		switch(c &= 0177)
		{
		case XON:
		case XOFF:
			continue;
		default:
			if(Zctlesc && !(c & 0140))
				continue;
		case '\r':
		case '\n':
		case ZDLE:
			return(c);
		}
	}
}

/* Store long integer pos in Txhdr */
void
stohdr(pos)
long pos;
{
	Txhdr[ZP0] = pos;
	Txhdr[ZP1] = pos>>8;
	Txhdr[ZP2] = pos>>16;
	Txhdr[ZP3] = pos>>24;
}

/* Recover a long integer from a header */
long
rclhdr(hdr)
register char *hdr;
{
	register long l;

	l = (hdr[ZP3] & 0377);
	l = (l << 8) | (hdr[ZP2] & 0377);
	l = (l << 8) | (hdr[ZP1] & 0377);
	l = (l << 8) | (hdr[ZP0] & 0377);
	return(l);
}

/* end of zmodem.c */
/* vi: set tabstop=4 shiftwidth=4: */