1: /*
   2:  * File: zmr.c 07-30-1989
   3:  * Copyright 1988, 1989 Omen Technology Inc All Rights Reserved
   4:  *
   5:  *
   6:  *
   7:  * This module implements ZMODEM Run Length Encoding, an
   8:  * extension that was not funded by the original Telenet
   9:  * development contract.
  10:  *
  11:  * This software may be freely used for non commercial and
  12:  * educational (didactic only) purposes.  This software may also
  13:  * be freely used to support file transfer operations to or from
  14:  * licensed Omen Technology products.  Any programs which use
  15:  * part or all of this software must be provided in source form
  16:  * with this notice intact except by written permission from Omen
  17:  * Technology Incorporated.
  18:  *
  19:  * Use of this software for commercial or administrative purposes
  20:  * except when exclusively limited to interfacing Omen Technology
  21:  * products requires a per port license payment of $20.00 US per
  22:  * port (less in quantity).  Use of this code by inclusion,
  23:  * decompilation, reverse engineering or any other means
  24:  * constitutes agreement to these conditions and acceptance of
  25:  * liability to license the materials and payment of reasonable
  26:  * legal costs necessary to enforce this license agreement.
  27:  *
  28:  *
  29:  *		Omen Technology Inc		FAX: 503-621-3745
  30:  *		Post Office Box 4681
  31:  *		Portland OR 97208
  32:  *
  33:  *	This code is made available in the hope it will be useful,
  34:  *	BUT WITHOUT ANY WARRANTY OF ANY KIND OR LIABILITY FOR ANY
  35:  *	DAMAGES OF ANY KIND.
  36:  *
  37:  *	ZMODEM RLE compression and decompression functions
  38:  */
  39: 
  40: /* Send data subpacket RLE encoded with 32 bit FCS */
  41: zsdar32(buf, length, frameend)
  42: char *buf;
  43: {
  44:     register int c, l, n;
  45:     register UNSL long crc;
  46: 
  47:     crc = 0xFFFFFFFFL;  l = *buf++ & 0377;
  48:     if (length == 1) {
  49:         zsendline(l); crc = UPDC32(l, crc);
  50:         if (l == ZRESC) {
  51:             zsendline(1); crc = UPDC32(1, crc);
  52:         }
  53:     } else {
  54:         for (n = 0; --length >= 0; ++buf) {
  55:             if ((c = *buf & 0377) == l && n < 126 && length>0) {
  56:                 ++n;  continue;
  57:             }
  58:             switch (n) {
  59:             case 0:
  60:                 zsendline(l);
  61:                 crc = UPDC32(l, crc);
  62:                 if (l == ZRESC) {
  63:                     zsendline(0100); crc = UPDC32(0100, crc);
  64:                 }
  65:                 l = c; break;
  66:             case 1:
  67:                 if (l != ZRESC) {
  68:                     zsendline(l); zsendline(l);
  69:                     crc = UPDC32(l, crc);
  70:                     crc = UPDC32(l, crc);
  71:                     n = 0; l = c; break;
  72:                 }
  73:                 /* **** FALL THRU TO **** */
  74:             default:
  75:                 zsendline(ZRESC); crc = UPDC32(ZRESC, crc);
  76:                 if (l == 040 && n < 34) {
  77:                     n += 036;
  78:                     zsendline(n); crc = UPDC32(n, crc);
  79:                 }
  80:                 else {
  81:                     n += 0101;
  82:                     zsendline(n); crc = UPDC32(n, crc);
  83:                     zsendline(l); crc = UPDC32(l, crc);
  84:                 }
  85:                 n = 0; l = c; break;
  86:             }
  87:         }
  88:     }
  89:     xsendline(ZDLE); xsendline(frameend);
  90:     crc = UPDC32(frameend, crc);
  91: 
  92:     crc = ~crc;
  93:     for (length=4; --length >= 0;) {
  94:         zsendline((int)crc);  crc >>= 8;
  95:     }
  96: }
  97: 
  98: 
  99: /* Receive data subpacket RLE encoded with 32 bit FCS */
 100: zrdatr32(buf, length)
 101: register char *buf;
 102: {
 103:     register int c;
 104:     register UNSL long crc;
 105:     register char *end;
 106:     register int d;
 107: 
 108:     crc = 0xFFFFFFFFL;  Rxcount = 0;  end = buf + length;
 109:     d = 0;  /* Use for RLE decoder state */
 110:     while (buf <= end) {
 111:         if ((c = zdlread()) & ~0377) {
 112: crcfoo:
 113:             switch (c) {
 114:             case GOTCRCE:
 115:             case GOTCRCG:
 116:             case GOTCRCQ:
 117:             case GOTCRCW:
 118:                 d = c;  c &= 0377;
 119:                 crc = UPDC32(c, crc);
 120:                 if ((c = zdlread()) & ~0377)
 121:                     goto crcfoo;
 122:                 crc = UPDC32(c, crc);
 123:                 if ((c = zdlread()) & ~0377)
 124:                     goto crcfoo;
 125:                 crc = UPDC32(c, crc);
 126:                 if ((c = zdlread()) & ~0377)
 127:                     goto crcfoo;
 128:                 crc = UPDC32(c, crc);
 129:                 if ((c = zdlread()) & ~0377)
 130:                     goto crcfoo;
 131:                 crc = UPDC32(c, crc);
 132:                 if (crc != 0xDEBB20E3) {
 133:                     zperr(badcrc);
 134:                     return ERROR;
 135:                 }
 136:                 Rxcount = length - (end - buf);
 137: #ifndef DSZ
 138:                 vfile("zrdatr32: %d %s", Rxcount,
 139:                   Zendnames[d-GOTCRCE&3]);
 140: #endif
 141:                 return d;
 142:             case GOTCAN:
 143:                 zperr("Sender Canceled");
 144:                 return ZCAN;
 145:             case TIMEOUT:
 146:                 zperr("TIMEOUT");
 147:                 return c;
 148:             default:
 149:                 zperr("Bad data subpacket");
 150:                 return c;
 151:             }
 152:         }
 153:         crc = UPDC32(c, crc);
 154:         switch (d) {
 155:         case 0:
 156:             if (c == ZRESC) {
 157:                 d = -1;  continue;
 158:             }
 159:             *buf++ = c;  continue;
 160:         case -1:
 161:             if (c >= 040 && c < 0100) {
 162:                 d = c - 035; c = 040;  goto spaces;
 163:             }
 164:             if (c == 0100) {
 165:                 d = 0;
 166:                 *buf++ = ZRESC;  continue;
 167:             }
 168:             d = c;  continue;
 169:         default:
 170:             d -= 0100;
 171:             if (d < 1)
 172:                 goto badpkt;
 173: spaces:
 174:             if ((buf + d) > end)
 175:                 goto badpkt;
 176:             while ( --d >= 0)
 177:                 *buf++ = c;
 178:             d = 0;  continue;
 179:         }
 180:     }
 181: badpkt:
 182:     zperr("Data subpacket too long");
 183:     return ERROR;
 184: }

Defined functions

zrdatr32 defined in line 100; used 1 times
zsdar32 defined in line 41; used 1 times

Usage of this include

Last modified: 1992-06-14
Generated: 2016-12-26
Generated by src2html V0.67
page hit count: 1443
Valid CSS Valid XHTML 1.0 Strict