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 #define CATV_OPT_e (1<<0)
  30 #define CATV_OPT_t (1<<1)
  31 #define CATV_OPT_v (1<<2)
  32         typedef char BUG_const_mismatch[
  33                 CATV_OPT_e == VISIBLE_ENDLINE && CATV_OPT_t == VISIBLE_SHOW_TABS
  34                 ? 1 : -1
  35         ];
  36
  37         opts = getopt32(argv, "etv");
  38         argv += optind;
  39 #if 0 /* These consts match, we can just pass "opts" to visible() */
  40         if (opts & CATV_OPT_e)
  41                 flags |= VISIBLE_ENDLINE;
  42         if (opts & CATV_OPT_t)
  43                 flags |= VISIBLE_SHOW_TABS;
  44 #endif
  45
  46         /* Read from stdin if there's nothing else to do. */
  47         if (!argv[0])
  48                 *--argv = (char*)"-";
  49         do {
  50                 fd = open_or_warn_stdin(*argv);
  51                 if (fd < 0) {
  52                         retval = EXIT_FAILURE;
  53                         continue;
  54                 }
  55                 for (;;) {
  56                         int i, res;
  57
  58 #define read_buf bb_common_bufsiz1
  59                         res = read(fd, read_buf, COMMON_BUFSIZE);
  60                         if (res < 0)
  61                                 retval = EXIT_FAILURE;
  62                         if (res <= 0)
  63                                 break;
  64                         for (i = 0; i < res; i++) {
  65                                 unsigned char c = read_buf[i];
  66                                 if (opts & CATV_OPT_v) {
  67                                         putchar(c);
  68                                 } else {
  69                                         char buf[sizeof("M-^c")];
  70                                         visible(c, buf, opts);
  71                                         fputs(buf, stdout);
  72                                 }
  73                         }
  74                 }
  75                 if (ENABLE_FEATURE_CLEAN_UP && fd)
  76                         close(fd);
  77         } while (*++argv);
  78
  79         fflush_stdout_and_exit(retval);
  80 }