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;
  19         int fd;
  20         unsigned flags;
  21
  22         flags = getopt32(argv, "etv");
  23 #define CATV_OPT_e (1<<0)
  24 #define CATV_OPT_t (1<<1)
  25 #define CATV_OPT_v (1<<2)
  26         flags ^= CATV_OPT_v;
  27         argv += optind;
  28
  29         /* Read from stdin if there's nothing else to do. */
  30         fd = 0;
  31         if (!argv[0]) {
  32                 argv--;
  33                 goto jump_in;
  34         }
  35         do {
  36                 fd = open_or_warn(*argv, O_RDONLY);
  37                 if (fd < 0) {
  38                         retval = EXIT_FAILURE;
  39                         continue;
  40                 }
  41  jump_in:
  42                 for (;;) {
  43                         int i, res;
  44
  45 #define read_buf bb_common_bufsiz1
  46                         res = read(fd, read_buf, COMMON_BUFSIZE);
  47                         if (res < 0)
  48                                 retval = EXIT_FAILURE;
  49                         if (res < 1)
  50                                 break;
  51                         for (i = 0; i < res; i++) {
  52                                 unsigned char c = read_buf[i];
  53
  54                                 if (c > 126 && (flags & CATV_OPT_v)) {
  55                                         if (c == 127) {
  56                                                 printf("^?");
  57                                                 continue;
  58                                         }
  59                                         printf("M-");
  60                                         c -= 128;
  61                                 }
  62                                 if (c < 32) {
  63                                         if (c == 10) {
  64                                                 if (flags & CATV_OPT_e)
  65                                                         putchar('$');
  66                                         } else if (flags & (c==9 ? CATV_OPT_t : CATV_OPT_v)) {
  67                                                 printf("^%c", c+'@');
  68                                                 continue;
  69                                         }
  70                                 }
  71                                 putchar(c);
  72                         }
  73                 }
  74                 if (ENABLE_FEATURE_CLEAN_UP && fd)
  75                         close(fd);
  76         } while (*++argv);
  77
  78         fflush_stdout_and_exit(retval);
  79 }