toys/other/catv.c

/* cat -v implementation for toybox
 *
 * Copyright (C) 2006, 2007 Rob Landley <rob@landley.net>
 *
 * See "Cat -v considered harmful" at
 *   http://cm.bell-labs.com/cm/cs/doc/84/kp.ps.gz

USE_CATV(NEWTOY(catv, "vte", TOYFLAG_USR|TOYFLAG_BIN))

config CATV
  bool "catv"
  default y
  help
    usage: catv [-evt] [filename...]

    Display nonprinting characters as escape sequences. Use M-x for
    high ascii characters (>127), and ^x for other nonprinting chars.

    -e	Mark each newline with $
    -t	Show tabs as ^I
    -v	Don't use ^x or M-x escapes.
*/

#define FOR_catv
#include "toys.h"

// Callback function for loopfiles()

static void do_catv(int fd, char *name)
{
  for(;;) {
    int i, len;

    len = read(fd, toybuf, sizeof(toybuf));
    if (len < 0) toys.exitval = EXIT_FAILURE;
    if (len < 1) break;
    for (i=0; i<len; i++) {
      char c=toybuf[i];

      if (c > 126 && (toys.optflags & FLAG_v)) {
        if (c > 127) {
          printf("M-");
          c -= 128;
        }
        if (c == 127) {
          printf("^?");
          continue;
        }
      }
      if (c < 32) {
        if (c == 10) {
          if (toys.optflags & FLAG_e) xputc('$');
        } else if (toys.optflags & (c==9 ? FLAG_t : FLAG_v)) {
          printf("^%c", c+'@');
          continue;
        }
      }
      xputc(c);
    }
  }
}

void catv_main(void)
{
  toys.optflags ^= FLAG_v;
  loopfiles(toys.optargs, do_catv);
}