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 source tree.
   8  */
   9
  10 /* See "Cat -v considered harmful" at
  11  * http://cm.bell-labs.com/cm/cs/doc/84/kp.ps.gz */
  12
  13 //usage:#define catv_trivial_usage
  14 //usage:       "[-etv] [FILE]..."
  15 //usage:#define catv_full_usage "\n\n"
  16 //usage:       "Display nonprinting characters as ^x or M-x\n"
  17 //usage:     "\n        -e      End each line with $"
  18 //usage:     "\n        -t      Show tabs as ^I"
  19 //usage:     "\n        -v      Don't use ^x or M-x escapes"
  20
  21 #include "libbb.h"
  22
  23 int catv_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  24 int catv_main(int argc UNUSED_PARAM, char **argv)
  25 {
  26         int retval = EXIT_SUCCESS;
  27         int fd;
  28         unsigned opts;
  29         int flags = 0;
  30
  31         opts = getopt32(argv, "etv");
  32 #define CATV_OPT_e (1<<0)
  33 #define CATV_OPT_t (1<<1)
  34 #define CATV_OPT_v (1<<2)
  35         argv += optind;
  36         if (opts & (CATV_OPT_e | CATV_OPT_t))
  37                 opts &= ~CATV_OPT_v;
  38         if (opts & CATV_OPT_e)
  39                 flags |= VISIBLE_ENDLINE;
  40         if (opts & CATV_OPT_t)
  41                 flags |= VISIBLE_SHOW_TABS;
  42
  43         /* Read from stdin if there's nothing else to do. */
  44         if (!argv[0])
  45                 *--argv = (char*)"-";
  46         do {
  47                 fd = open_or_warn_stdin(*argv);
  48                 if (fd < 0) {
  49                         retval = EXIT_FAILURE;
  50                         continue;
  51                 }
  52                 for (;;) {
  53                         int i, res;
  54
  55 #define read_buf bb_common_bufsiz1
  56                         res = read(fd, read_buf, COMMON_BUFSIZE);
  57                         if (res < 0)
  58                                 retval = EXIT_FAILURE;
  59                         if (res <= 0)
  60                                 break;
  61                         for (i = 0; i < res; i++) {
  62                                 unsigned char c = read_buf[i];
  63                                 if (opts & CATV_OPT_v) {
  64                                         putchar(c);
  65                                 } else {
  66                                         char buf[sizeof("M-^c")];
  67                                         visible(c, buf, flags);
  68                                         fputs(buf, stdout);
  69                                 }
  70                         }
  71                 }
  72                 if (ENABLE_FEATURE_CLEAN_UP && fd)
  73                         close(fd);
  74         } while (*++argv);
  75
  76         fflush_stdout_and_exit(retval);
  77 }