Last active
April 2, 2017 14:40
-
-
Save elieux/85ea9477256f417530cc to your computer and use it in GitHub Desktop.
PHP Unserializer
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| <?php | |
| /* | |
| * Custom PHP unserializer with better error reporting | |
| * | |
| * Does not support objects. | |
| */ | |
| class Unserializer { | |
| private $serialized; | |
| private $len; | |
| private $i; | |
| public function __construct($serialized) { | |
| $this->serialized = $serialized; | |
| $this->len = strlen($this->serialized); | |
| $this->i = 0; | |
| } | |
| private function read() { | |
| if ($this->i >= $this->len) { | |
| $this->err("Unexpected end"); | |
| } | |
| $b = substr($this->serialized, $this->i, 1); | |
| $this->i++; | |
| return $b; | |
| } | |
| private function err($msg) { | |
| $offset = $this->i - 1; | |
| throw new Exception("{$msg} at {$offset}"); | |
| } | |
| private function arr() { | |
| $len = $this->num(true); | |
| $this->byte(':'); | |
| $this->byte('{'); | |
| $result = array(); | |
| while ($len-- > 0) { | |
| $key = $this->any(); | |
| if (!is_scalar($key)) { | |
| $this->err("Non-scalar key"); | |
| } | |
| if (isset($result[$key])) { | |
| $this->err("Duplicate key '{$key}'"); | |
| } | |
| $value = $this->any(); | |
| $result[$key] = $value; | |
| } | |
| $this->byte('}'); | |
| return $result; | |
| } | |
| private function num($int_only = false) { | |
| $result = 0; | |
| $b = $this->byte('0123456789'); | |
| $result *= 10; | |
| $result += $b; | |
| while (true) { | |
| $b = $this->byte($int_only ? '0123456789' : '0123456789.', false); | |
| if ($b === null) { | |
| return $result; | |
| } | |
| if ($b === '.') { | |
| break; | |
| } | |
| $result *= 10; | |
| $result += $b; | |
| } | |
| $denom = 1; | |
| while (true) { | |
| $b = $this->byte('0123456789', false); | |
| if ($b === null) { | |
| return $result; | |
| } | |
| $denom *= 10; | |
| $result += $b / $denom; | |
| } | |
| } | |
| private function bool() { | |
| $b = $this->byte('01'); | |
| if ($b == '1') { | |
| $result = true; | |
| } else if ($b == '0') { | |
| $result = false; | |
| } | |
| $this->byte(';'); | |
| return $result; | |
| } | |
| private function str() { | |
| $len = $this->num(true); | |
| $this->byte(':'); | |
| $this->byte('"'); | |
| $result = ''; | |
| while ($len-- > 0) { | |
| $result .= $this->read(); | |
| } | |
| $this->byte('"'); | |
| $this->byte(';'); | |
| return $result; | |
| } | |
| private function byte($exp, $err = true) { | |
| $exp = str_split($exp); | |
| $b = $this->read(); | |
| if (!in_array($b, $exp, true)) { | |
| if ($err) { | |
| $exp = implode(' or ', array_map(function($c) { return "'{$c}'"; }, $exp)); | |
| $this->err("Unexpected '{$b}' (expecting {$exp})"); | |
| } else { | |
| $this->i--; | |
| return null; | |
| } | |
| } | |
| return $b; | |
| } | |
| private function any() { | |
| $b = $this->byte('bidsaN'); | |
| if (in_array($b, array('b', 'i', 'd', 's', 'a'))) { | |
| $this->byte(':'); | |
| if ($b === 'b') { | |
| $result = $this->bool(); | |
| } else if ($b === 'i' || $b === 'd') { | |
| $result = $this->num(); | |
| $this->byte(';'); | |
| } else if ($b === 's') { | |
| $result = $this->str(); | |
| } else if ($b === 'a') { | |
| $result = $this->arr(); | |
| } | |
| } else if ($b === 'N') { | |
| $result = null; | |
| $this->byte(';'); | |
| } | |
| return $result; | |
| } | |
| public function unserialize() { | |
| $result = $this->any(); | |
| if ($this->len !== $this->i) { | |
| $this->err("Unexpected more bytes"); | |
| } | |
| return $result; | |
| } | |
| } |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment