1/* uudecode.c - uudecode / base64 decode
2 *
3 * Copyright 2013 Erich Plondke <toybox@erich.wreck.org>
4 *
5 * See http://pubs.opengroup.org/onlinepubs/9699919799/utilities/uudecode.html
6
7USE_UUDECODE(NEWTOY(uudecode, ">1o:", TOYFLAG_USR|TOYFLAG_BIN|TOYFLAG_UMASK))
8
9config UUDECODE
10  bool "uudecode"
11  default y
12  help
13    usage: uudecode [-o OUTFILE] [INFILE]
14
15    Decode file from stdin (or INFILE).
16
17    -o	write to OUTFILE instead of filename in header
18*/
19
20#define FOR_uudecode
21#include "toys.h"
22
23GLOBALS(
24  char *o;
25)
26
27void uudecode_main(void)
28{
29  int ifd = 0, ofd, idx = 0, m = m;
30  char *line = 0, mode[16],
31       *class[] = {"begin%*[ ]%15s%*[ ]%n", "begin-base64%*[ ]%15s%*[ ]%n"};
32
33  if (toys.optc) ifd = xopenro(*toys.optargs);
34
35  while (!idx) {
36    free(line);
37    if (!(line = get_line(ifd))) error_exit("bad EOF");
38    for (m=0; m < 2; m++) {
39      sscanf(line, class[m], mode, &idx);
40      if (idx) break;
41    }
42  }
43
44  ofd = xcreate(TT.o ? TT.o : line+idx, O_WRONLY|O_CREAT|O_TRUNC,
45    string_to_mode(mode, 0777^toys.old_umask));
46
47  for(;;) {
48    char *in, *out;
49    int olen;
50
51    free(line);
52    if (m == 2 || !(line = get_line(ifd))) break;
53    if (!strcmp(line, m ? "====" : "end")) {
54      m = 2;
55      continue;
56    }
57
58    olen = 0;
59    in = out = line;
60    if (!m) olen = (*(in++) - 32) & 0x3f;
61
62    for (;;) {
63      int i = 0, x = 0, len = 4;
64      char c = 0;
65
66      if (!m) {
67        if (olen < 1) break;
68        if (olen < 3) len = olen + 1;
69      }
70
71      while (i < len) {
72        if (!(c = *(in++))) goto line_done;
73
74        if (m) {
75          if (c == '=') {
76            len--;
77            continue;
78          } else if (len != 4) break;
79
80          if (c >= 'A' && c <= 'Z') c -= 'A';
81          else if (c >= 'a' && c <= 'z') c += 26 - 'a';
82          else if (c >= '0' && c <= '9') c += 52 - '0';
83          else if (c == '+') c = 62;
84          else if (c == '/') c = 63;
85          else continue;
86        } else c = (c - 32) & 0x3f;
87
88        x |= c << (6*(3-i));
89
90        if (i && i < len) {
91          *(out++) = (x>>(8*(3-i))) & 0xff;
92          olen--;
93        }
94        i++;
95      }
96
97      if (i && i!=len) error_exit("bad %s", line);
98    }
99line_done:
100    xwrite(ofd, line, out-line);
101  }
102
103  if (CFG_TOYBOX_FREE) {
104    if (ifd) close(ifd);
105    close(ofd);
106  }
107}
108