coreutils/catv.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * cat -v implementation for busybox
   4  *
   5  * Copyright (C) 2006 Rob Landley <rob@landley.net>
   6  *
   7  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
   8  */
   9
  10 /* See "Cat -v considered harmful" at
  11  * http://cm.bell-labs.com/cm/cs/doc/84/kp.ps.gz */
  12
  13 #include "libbb.h"
  14
  15 int catv_main(int argc, char **argv);
  16 int catv_main(int argc, char **argv)
  17 {
  18         int retval = EXIT_SUCCESS, fd;
  19         unsigned flags;
  20
  21         flags = getopt32(argc, argv, "etv");
  22 #define CATV_OPT_e (1<<0)
  23 #define CATV_OPT_t (1<<1)
  24 #define CATV_OPT_v (1<<2)
  25         flags ^= CATV_OPT_v;
  26
  27         argv += optind;
  28         do {
  29                 /* Read from stdin if there's nothing else to do. */
  30                 fd = 0;
  31                 if (*argv && 0 > (fd = xopen(*argv, O_RDONLY)))
  32                         retval = EXIT_FAILURE;
  33                 else for (;;) {
  34                         int i, res;
  35
  36                         res = read(fd, bb_common_bufsiz1, sizeof(bb_common_bufsiz1));
  37                         if (res < 0)
  38                                 retval = EXIT_FAILURE;
  39                         if (res < 1)
  40                                 break;
  41                         for (i = 0; i < res; i++) {
  42                                 char c = bb_common_bufsiz1[i];
  43
  44                                 if (c > 126 && (flags & CATV_OPT_v)) {
  45                                         if (c == 127) {
  46                                                 printf("^?");
  47                                                 continue;
  48                                         } else {
  49                                                 printf("M-");
  50                                                 c -= 128;
  51                                         }
  52                                 }
  53                                 if (c < 32) {
  54                                         if (c == 10) {
  55                                                 if (flags & CATV_OPT_e)
  56                                                         putchar('$');
  57                                         } else if (flags & (c==9 ? CATV_OPT_t : CATV_OPT_v)) {
  58                                                 printf("^%c", c+'@');
  59                                                 continue;
  60                                         }
  61                                 }
  62                                 putchar(c);
  63                         }
  64                 }
  65                 if (ENABLE_FEATURE_CLEAN_UP && fd)
  66                         close(fd);
  67         } while (*++argv);
  68
  69         fflush_stdout_and_exit(retval);
  70 }