/* * File: zmr.c * Copyright 1988, 1994 Omen Technology Inc All Rights Reserved * * *  * This module implements ZMODEM Run Length Encoding, an * extension that was not funded by the original Telenet * development contract. *  *  This software may be freely used for educational (didactic *  only) purposes.  This software may also be freely used to *  support file transfer operations to or from licensed Omen *  Technology products.  Use with other commercial or shareware *  programs (Crosstalk, Procomm, etc.) REQUIRES REGISTRATION. * *  Any programs which use part or all of this software must be *  provided in source form with this notice intact except by *  written permission from Omen Technology Incorporated. *  * Use of this software for commercial or administrative purposes * except when exclusively limited to interfacing Omen Technology * products requires a per port license payment of $20.00 US per * port (less in quantity).  Use of this code by inclusion, * decompilation, reverse engineering or any other means * constitutes agreement to these conditions and acceptance of * liability to license the materials and payment of reasonable * legal costs necessary to enforce this license agreement. * * *		Omen Technology Inc *		Post Office Box 4681 *		Portland OR 97208 * *	This code is made available in the hope it will be useful, *	BUT WITHOUT ANY WARRANTY OF ANY KIND OR LIABILITY FOR ANY *	DAMAGES OF ANY KIND. * *	ZMODEM RLE compression and decompression functions *//* Send data subpacket RLE encoded with 32 bit FCS */zsdar32(buf, length, frameend)char *buf;{	register int c, l, n;	register unsigned long crc;	crc = 0xFFFFFFFFL;  l = *buf++ & 0377;	if (length == 1) {		zsendline(l); crc = UPDC32(l, crc);		if (l == ZRESC) {			zsendline(1); crc = UPDC32(1, crc);		}	} else {		for (n = 0; --length >= 0; ++buf) {			if ((c = *buf & 0377) == l && n < 126 && length>0) {				++n;  continue;			}			switch (n) {			case 0:				zsendline(l);				crc = UPDC32(l, crc);				if (l == ZRESC) {					zsendline(0100); crc = UPDC32(0100, crc);				}				l = c; break;			case 1:				if (l != ZRESC) {					zsendline(l); zsendline(l);					crc = UPDC32(l, crc);					crc = UPDC32(l, crc);					n = 0; l = c; break;				}				/* **** FALL THRU TO **** */			default:				zsendline(ZRESC); crc = UPDC32(ZRESC, crc);				if (l == 040 && n < 34) {					n += 036;					zsendline(n); crc = UPDC32(n, crc);				}				else {					n += 0101;					zsendline(n); crc = UPDC32(n, crc);					zsendline(l); crc = UPDC32(l, crc);				}				n = 0; l = c; break;			}		}	}	xsendline(ZDLE); xsendline(frameend);	crc = UPDC32(frameend, crc);	crc = ~crc;	for (length=4; --length >= 0;) {		zsendline((int)crc);  crc >>= 8;	}}/* Receive data subpacket RLE encoded with 32 bit FCS */zrdatr32(buf, length)register char *buf;{	register int c;	register unsigned long crc;	register char *end;	register int d;	crc = 0xFFFFFFFFL;  Rxcount = 0;  end = buf + length;	d = 0;	/* Use for RLE decoder state */	while (buf <= end) {		if ((c = zdlread()) & ~0377) {crcfoo:			switch (c) {			case GOTCRCE:			case GOTCRCG:			case GOTCRCQ:			case GOTCRCW:				d = c;  c &= 0377;				crc = UPDC32(c, crc);				if ((c = zdlread()) & ~0377)					goto crcfoo;				crc = UPDC32(c, crc);				if ((c = zdlread()) & ~0377)					goto crcfoo;				crc = UPDC32(c, crc);				if ((c = zdlread()) & ~0377)					goto crcfoo;				crc = UPDC32(c, crc);				if ((c = zdlread()) & ~0377)					goto crcfoo;				crc = UPDC32(c, crc);				if (crc != 0xDEBB20E3) {					zperr(badcrc);					return ERROR;				}				Rxcount = length - (end - buf);#ifndef DSZ				vfile("zrdatr32: %d %s", Rxcount,				  Zendnames[d-GOTCRCE&3]);#endif				return d;			case GOTCAN:				zperr("Sender Canceled");				return ZCAN;			case TIMEOUT:				zperr("TIMEOUT");				return c;			default:				zperr("Bad data subpacket");				return c;			}		}		crc = UPDC32(c, crc);		switch (d) {		case 0:			if (c == ZRESC) {				d = -1;  continue;			}			*buf++ = c;  continue;		case -1:			if (c >= 040 && c < 0100) {				d = c - 035; c = 040;  goto spaces;			}			if (c == 0100) {				d = 0;				*buf++ = ZRESC;  continue;			}			d = c;  continue;		default:			d -= 0100;			if (d < 1)				goto badpkt;spaces:			if ((buf + d) > end)				goto badpkt;			while ( --d >= 0)				*buf++ = c;			d = 0;  continue;		}	}badpkt:	zperr("Data subpacket too long");	return ERROR;}/* End of zmr.c */