LXR toybox/toys/other/rev.c

   1/* rev.c - reverse lines of a set of given input files
   2 *
   3 * Copyright 2012 Elie De Brauwer <eliedebrauwer@gmail.com>
   4
   5USE_REV(NEWTOY(rev, NULL, TOYFLAG_USR|TOYFLAG_BIN))
   6
   7config REV
   8  bool "rev"
   9  default y
  10  help
  11    usage: rev [FILE...]
  12
  13    Output each line reversed, when no files are given stdin is used.
  14*/
  15
  16#include "toys.h"
  17
  18static void rev_line(char **pline, long len)
  19{
  20  char *line;
  21  long i;
  22
  23  if (!pline) return;
  24  line = *pline;
  25  if (len && line[len-1]=='\n') line[--len] = 0;
  26
  27  if (len--) for (i = 0; i <= len/2; i++) {
  28    char tmp = line[i];
  29
  30    line[i] = line[len-i];
  31    line[len-i] = tmp;
  32  }
  33  xputs(line);
  34}
  35
  36void rev_main(void)
  37{
  38  loopfiles_lines(toys.optargs, rev_line);
  39}
  40