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/*
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>
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);
}
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