tracker/bencoder.php

83 lines
No EOL
1.6 KiB
PHP

<?php
function bencode($var)
{
if (is_string($var)) {
return strlen($var) .':'. $var;
} else if (is_int($var)) {
return 'i'. $var .'e';
} else if (is_float($var)) {
return 'i'. sprintf('%.0f', $var) .'e';
} else if (is_array($var)) {
if (count($var) == 0) {
return 'de';
} else {
$assoc = false;
foreach ($var as $key => $val) {
if (!is_int($key)) {
$assoc = true;
break;
}
}
if ($assoc) {
ksort($var, SORT_REGULAR);
$ret = 'd';
foreach ($var as $key => $val) {
$ret .= bencode($key) . bencode($val);
}
return $ret .'e';
} else {
$ret = 'l';
foreach ($var as $val) {
$ret .= bencode($val);
}
return $ret .'e';
}
}
} else {
do_error('bencode wrong data type');
}
}
function bdecode($enc, &$off = null)
{
$result = null;
if ($off == null) {
$_off = 0;
$off = $_off;
}
$type = substr($enc, $off, 1);
if ($type == 'i') {
$end = strpos($enc, 'e', $off + 1);
$result = intval(substr($enc, $off + 1, $end - $off - 1));
$off = $end + 1;
} else if ($type == 'l') {
$off++;
$result = array();
while (substr($enc, $off, 1) != 'e') {
array_push($result, bdecode($enc, $off));
}
} else if ($type == 'd') {
$off++;
$result = array();
while (substr($enc, $off, 1) != 'e') {
$key = bdecode($enc, $off);
$value = bdecode($enc, $off);
$result[$key] = $value;
}
} else {
$sep = strpos($enc, ':', $off);
$len = intval(substr($enc, $off, $sep - $off));
$result = substr($enc, $sep + 1, $len);
$off = $sep + 1 + $len;
}
return $result;
}
?>