BSD 4_3_Tahoe release

[unix-history] / usr / src / usr.bin / uucp / uudecode.c

/*
* Copyright (c) 1983 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by the University of California, Berkeley.  The name of the
* University may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/

#ifndef lint
static char sccsid[] = "@(#)uudecode.c  5.5 (Berkeley) 7/6/88";
#endif /* not lint */

/*
* uudecode [input]
*
* create the specified file, decoding as you go.
* used with uuencode.
*/
#include <stdio.h>
#include <pwd.h>
#include <sys/types.h>
#include <sys/stat.h>

/* single character decode */
#define DEC(c)  (((c) - ' ') & 077)

main(argc, argv)
char **argv;
{
       FILE *in, *out;
       int mode;
       char dest[128];
       char buf[80];

       /* optional input arg */
       if (argc > 1) {
               if ((in = fopen(argv[1], "r")) == NULL) {
                       perror(argv[1]);
                       exit(1);
               }
               argv++; argc--;
       } else
               in = stdin;

       if (argc != 1) {
               printf("Usage: uudecode [infile]\n");
               exit(2);
       }

       /* search for header line */
       for (;;) {
               if (fgets(buf, sizeof buf, in) == NULL) {
                       fprintf(stderr, "No begin line\n");
                       exit(3);
               }
               if (strncmp(buf, "begin ", 6) == 0)
                       break;
       }
       (void)sscanf(buf, "begin %o %s", &mode, dest);

       /* handle ~user/file format */
       if (dest[0] == '~') {
               char *sl;
               struct passwd *getpwnam();
               struct passwd *user;
               char dnbuf[100], *index(), *strcat(), *strcpy();

               sl = index(dest, '/');
               if (sl == NULL) {
                       fprintf(stderr, "Illegal ~user\n");
                       exit(3);
               }
               *sl++ = 0;
               user = getpwnam(dest+1);
               if (user == NULL) {
                       fprintf(stderr, "No such user as %s\n", dest);
                       exit(4);
               }
               strcpy(dnbuf, user->pw_dir);
               strcat(dnbuf, "/");
               strcat(dnbuf, sl);
               strcpy(dest, dnbuf);
       }

       /* create output file */
       out = fopen(dest, "w");
       if (out == NULL) {
               perror(dest);
               exit(4);
       }
       chmod(dest, mode);

       decode(in, out);

       if (fgets(buf, sizeof buf, in) == NULL || strcmp(buf, "end\n")) {
               fprintf(stderr, "No end line\n");
               exit(5);
       }
       exit(0);
}

/*
* copy from in to out, decoding as you go along.
*/
decode(in, out)
FILE *in;
FILE *out;
{
       char buf[80];
       char *bp;
       int n;

       for (;;) {
               /* for each input line */
               if (fgets(buf, sizeof buf, in) == NULL) {
                       printf("Short file\n");
                       exit(10);
               }
               n = DEC(buf[0]);
               if (n <= 0)
                       break;

               bp = &buf[1];
               while (n > 0) {
                       outdec(bp, out, n);
                       bp += 4;
                       n -= 3;
               }
       }
}

/*
* output a group of 3 bytes (4 input characters).
* the input chars are pointed to by p, they are to
* be output to file f.  n is used to tell us not to
* output all of them at the end of the file.
*/
outdec(p, f, n)
char *p;
FILE *f;
{
       int c1, c2, c3;

       c1 = DEC(*p) << 2 | DEC(p[1]) >> 4;
       c2 = DEC(p[1]) << 4 | DEC(p[2]) >> 2;
       c3 = DEC(p[2]) << 6 | DEC(p[3]);
       if (n >= 1)
               putc(c1, f);
       if (n >= 2)
               putc(c2, f);
       if (n >= 3)
               putc(c3, f);
}