/* ecc Version 1.2 by Paul Flaherty (paulf@stanford.edu) Copyright (C) 1993 Free Software Foundation, Inc. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ /* ecc.c Basic Software Tool for Encoding and Decoding Files. This is a simple stream encoder which uses the rslib routines to do something practical. It reads data from stdin in 248(encode) or 256(decode) blocks, and writes the corresponding encoded/decoded block onto stdout. An encoded block contains 248 data bytes, one length byte, six redundancy bytes, and a capital G byte as a sync marker to round it out to 256 bytes. */ #include <stdio.h> #include <sys/types.h> /* Also uses rslib.c and version.c */ main (argc, argv) int argc; char *argv[]; { int ec; if (argc != 2) { fprintf (stderr, "usage: ecc [-edv] \n"); exit (1); } if (strcmp ("-e", argv[1]) == 0) encode (); if (strcmp ("-d", argv[1]) == 0) decode (); if (strcmp ("-v", argv[1]) == 0) ver (); fprintf (stderr, "usage: ecc [-edv] \n"); exit (1); } ver () { extern char version[]; fprintf (stderr, "%s\n", version); exit (0); } encode () { unsigned char msg[249], coded[255]; int i, readme; for (i = 0; i < 249; i++) msg[i] = 0; readme = 248; while (readme == 248) { readme = fread (msg, 1, 248, stdin); msg[248] = readme; rsencode (msg, coded); fprintf (stdout, "G"); for (i = 254; i > -1; i--) fprintf (stdout, "%c", coded[i]); } exit (0); } decode () { int i, j, readme, bo, len; unsigned char msgs[249], cod[255]; j = 0; while (getc (stdin) == 71) { j++; for (i = 254; i > -1; i--) cod[i] = getc (stdin); rsdecode (cod, msgs, &bo); if (bo > 0 && bo < 4) fprintf (stderr, "ecc: %d byte error in block %d.\n", bo, j); if (bo == 4) fprintf (stderr, "ecc: unrecoverable error in block %d.\n", j); len = msgs[248]; for (i = 0; i < len; i++) putc (msgs[i], stdout); } if (getc (stdin) != EOF) { fprintf (stderr, "ecc: sync error in block %d.\n", j); exit (1); } exit (0); }
file: /Techref/method/error/rs-255-248-7-pf-1993/ecc_c.htm, 15KB, , updated: 2000/5/9 18:15, local time: 2024/11/25 05:02,
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Ashley Roll has put together a really nice little unit here. Leave off the MAX232 and keep these handy for the few times you need true RS232! |
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