<?php

/*

Brainfuck interpreter

by Lucas Oman
2006-02-14

*/

$c = file($argv[1]);
$c = implode('',$c);
$l = strlen($c);
$b = array();
$p = 0;
$si = fopen('php://stdin','r');
$sk = false;
$lc = 0;
$ls = array();
$i = 0;
while ($i<$l) {
  $tc = $c{$i};
  if ($tc == ']') {
    if ($lc > 0) {
      $lc--;
    } elseif ($sk) {
      $sk = false;
    } else {
      $i = array_pop($ls);
      $tc = $c{$i};
    }
  } elseif ($sk) {
    $i++;
    continue;
  } elseif ($tc == '>') {
    $p++;
  } elseif ($tc == '<') {
    $p--;
  } elseif ($tc == '+') {
    if (!isset($b[$p])) {
      $b[$p] = 0;
    }
    $b[$p]++;
  } elseif ($tc == '-') {
    $b[$p]--;
  } elseif ($tc == '.') {
    print(chr($b[$p]));
  } elseif ($tc == ',') {
    $b[$p] = ord(fgetc($si));
  } elseif ($tc == '[') {
    if ($b[$p] <= 0) {
      $sk = true;
    } else {
      $ls[] = $i - 1;
    }
  }
  $i++;
}
fclose($si);

?>