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:     "\nOptions:"
  18 //usage:     "\n        -e      End each line with $"
  19 //usage:     "\n        -t      Show tabs as ^I"
  20 //usage:     "\n        -v      Don't use ^x or M-x escapes"
  21
  22 #include "libbb.h"
  23
  24 int catv_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  25 int catv_main(int argc UNUSED_PARAM, char **argv)
  26 {
  27         int retval = EXIT_SUCCESS;
  28         int fd;
  29         unsigned flags;
  30
  31         flags = 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         flags ^= CATV_OPT_v;
  36         argv += optind;
  37
  38         /* Read from stdin if there's nothing else to do. */
  39         if (!argv[0])
  40                 *--argv = (char*)"-";
  41         do {
  42                 fd = open_or_warn_stdin(*argv);
  43                 if (fd < 0) {
  44                         retval = EXIT_FAILURE;
  45                         continue;
  46                 }
  47                 for (;;) {
  48                         int i, res;
  49
  50 #define read_buf bb_common_bufsiz1
  51                         res = read(fd, read_buf, COMMON_BUFSIZE);
  52                         if (res < 0)
  53                                 retval = EXIT_FAILURE;
  54                         if (res < 1)
  55                                 break;
  56                         for (i = 0; i < res; i++) {
  57                                 unsigned char c = read_buf[i];
  58
  59                                 if (c > 126 && (flags & CATV_OPT_v)) {
  60                                         if (c == 127) {
  61                                                 printf("^?");
  62                                                 continue;
  63                                         }
  64                                         printf("M-");
  65                                         c -= 128;
  66                                 }
  67                                 if (c < 32) {
  68                                         if (c == 10) {
  69                                                 if (flags & CATV_OPT_e)
  70                                                         bb_putchar('$');
  71                                         } else if (flags & (c==9 ? CATV_OPT_t : CATV_OPT_v)) {
  72                                                 printf("^%c", c+'@');
  73                                                 continue;
  74                                         }
  75                                 }
  76                                 bb_putchar(c);
  77                         }
  78                 }
  79                 if (ENABLE_FEATURE_CLEAN_UP && fd)
  80                         close(fd);
  81         } while (*++argv);
  82
  83         fflush_stdout_and_exit(retval);
  84 }