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 #include "common_bufsiz.h"
  23
  24 #define CATV_OPT_e (1<<0)
  25 #define CATV_OPT_t (1<<1)
  26 #define CATV_OPT_v (1<<2)
  27 struct BUG_const_mismatch {
  28         char BUG_const_mismatch[
  29                 CATV_OPT_e == VISIBLE_ENDLINE && CATV_OPT_t == VISIBLE_SHOW_TABS
  30                 ? 1 : -1
  31         ];
  32 };
  33
  34 int catv_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  35 int catv_main(int argc UNUSED_PARAM, char **argv)
  36 {
  37         int retval = EXIT_SUCCESS;
  38         int fd;
  39         unsigned opts;
  40         opts = getopt32(argv, "etv");
  41         argv += optind;
  42 #if 0 /* These consts match, we can just pass "opts" to visible() */
  43         if (opts & CATV_OPT_e)
  44                 flags |= VISIBLE_ENDLINE;
  45         if (opts & CATV_OPT_t)
  46                 flags |= VISIBLE_SHOW_TABS;
  47 #endif
  48
  49         /* Read from stdin if there's nothing else to do. */
  50         if (!argv[0])
  51                 *--argv = (char*)"-";
  52
  53 #define read_buf bb_common_bufsiz1
  54         setup_common_bufsiz();
  55         do {
  56                 fd = open_or_warn_stdin(*argv);
  57                 if (fd < 0) {
  58                         retval = EXIT_FAILURE;
  59                         continue;
  60                 }
  61                 for (;;) {
  62                         int i, res;
  63
  64                         res = read(fd, read_buf, COMMON_BUFSIZE);
  65                         if (res < 0)
  66                                 retval = EXIT_FAILURE;
  67                         if (res <= 0)
  68                                 break;
  69                         for (i = 0; i < res; i++) {
  70                                 unsigned char c = read_buf[i];
  71                                 if (opts & CATV_OPT_v) {
  72                                         putchar(c);
  73                                 } else {
  74                                         char buf[sizeof("M-^c")];
  75                                         visible(c, buf, opts);
  76                                         fputs(buf, stdout);
  77                                 }
  78                         }
  79                 }
  80                 if (ENABLE_FEATURE_CLEAN_UP && fd)
  81                         close(fd);
  82         } while (*++argv);
  83
  84         fflush_stdout_and_exit(retval);
  85 }