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 #define read_buf bb_common_bufsiz1
  37                         res = read(fd, read_buf, COMMON_BUFSIZE);
  38                         if (res < 0)
  39                                 retval = EXIT_FAILURE;
  40                         if (res < 1)
  41                                 break;
  42                         for (i = 0; i < res; i++) {
  43                                 char c = read_buf[i];
  44
  45                                 if (c > 126 && (flags & CATV_OPT_v)) {
  46                                         if (c == 127) {
  47                                                 printf("^?");
  48                                                 continue;
  49                                         } else {
  50                                                 printf("M-");
  51                                                 c -= 128;
  52                                         }
  53                                 }
  54                                 if (c < 32) {
  55                                         if (c == 10) {
  56                                                 if (flags & CATV_OPT_e)
  57                                                         putchar('$');
  58                                         } else if (flags & (c==9 ? CATV_OPT_t : CATV_OPT_v)) {
  59                                                 printf("^%c", c+'@');
  60                                                 continue;
  61                                         }
  62                                 }
  63                                 putchar(c);
  64                         }
  65                 }
  66                 if (ENABLE_FEATURE_CLEAN_UP && fd)
  67                         close(fd);
  68         } while (*++argv);
  69
  70         fflush_stdout_and_exit(retval);
  71 }