toys/catv.c

   1 /* vi: set sw=4 ts=4:
   2  *
   3  * cat -v implementation for toybox
   4  *
   5  * Copyright (C) 2006, 2007 Rob Landley <rob@landley.net>
   6  *
   7  * Not in SUSv3, but see "Cat -v considered harmful" at
   8  *   http://cm.bell-labs.com/cm/cs/doc/84/kp.ps.gz
   9
  10 USE_CATV(NEWTOY(catv, "vte", TOYFLAG_USR|TOYFLAG_BIN))
  11
  12 config CATV
  13         bool "catv"
  14         default y
  15         help
  16           usage: catv [-evt] [filename...]
  17
  18           Display nonprinting characters as escape sequences.  Use M-x for
  19           high ascii characters (>127), and ^x for other nonprinting chars.
  20
  21           -e    Mark each newline with $
  22           -t    Show tabs as ^I
  23           -v    Don't use ^x or M-x escapes.
  24 */
  25
  26 #include "toys.h"
  27
  28 // Callback function for loopfiles()
  29
  30 static void do_catv(int fd, char *name)
  31 {
  32         for(;;) {
  33                 int i, len;
  34
  35                 len = read(fd, toybuf, sizeof(toybuf));
  36                 if (len < 0) toys.exitval = EXIT_FAILURE;
  37                 if (len < 1) break;
  38                 for (i=0; i<len; i++) {
  39                         char c=toybuf[i];
  40
  41                         if (c > 126 && (toys.optflags & 4)) {
  42                                 if (c == 127) {
  43                                         printf("^?");
  44                                         continue;
  45                                 } else {
  46                                         printf("M-");
  47                                         c -= 128;
  48                                 }
  49                         }
  50                         if (c < 32) {
  51                                 if (c == 10) {
  52                                         if (toys.optflags & 1) xputc('$');
  53                                 } else if (toys.optflags & (c==9 ? 2 : 4)) {
  54                                         printf("^%c", c+'@');
  55                                         continue;
  56                                 }
  57                         }
  58                         xputc(c);
  59                 }
  60         }
  61 }
  62
  63 void catv_main(void)
  64 {
  65         toys.optflags^=4;
  66         loopfiles(toys.optargs, do_catv);
  67 }