<?php
/******************************************************************************
*	Created by Joshua Dickerson (groundup)
*	PHP < 5.2 Filters
*
*	A port of the PHP filters for those that want to have the functions of the
*		PHP filters without upgrading or installing it via PECL.
*
*	See http://www.php.net/filter for more information about PHP filters.
******************************************************************************/

/*	USAGE:
		* Include this file in your script.
		* Call define_filter_constants().
		* Call the functions the same as is documented on the PHP website.

*/

/*	FUNCTION REFERENCE
	void define_filter_constants ()
		- Defines constants used in this script.

	 filter_has_var
		-
	 filter_id
		-
	 filter_input_array
		-
	 filter_input
		-
	 filter_list
		-
	 filter_var_array
		-
	 filter_var
		-
*/

// Define a LOT of constants
function define_filter_constants()
{
	$constants = array(
		'INPUT_POST' => 0,
		'INPUT_GET' => 1,
		'INPUT_COOKIE' => 2,
		'INPUT_ENV' => 4,
		'INPUT_SERVER' => 5,
		'FILTER_FLAG_NONE' => 0,
		'FILTER_REQUIRE_SCALAR' => 33554432,
		'FILTER_REQUIRE_ARRAY' => 16777216,
		'FILTER_FORCE_ARRAY' => 67108864,
		'FILTER_NULL_ON_FAILURE' => 134217728,
		'FILTER_VALIDATE_INT' => 257,
		'FILTER_VALIDATE_BOOLEAN' => 258,
		'FILTER_VALIDATE_FLOAT' => 259,
		'FILTER_VALIDATE_REGEXP' => 272,
		'FILTER_VALIDATE_URL' => 273,
		'FILTER_VALIDATE_EMAIL' => 274,
		'FILTER_VALIDATE_IP' => 275,
		'FILTER_DEFAULT' => 516,
		'FILTER_UNSAFE_RAW' => 516,
		'FILTER_SANITIZE_STRING' => 513,
		'FILTER_SANITIZE_STRIPPED' => 513,
		'FILTER_SANITIZE_ENCODED' => 514,
		'FILTER_SANITIZE_SPECIAL_CHARS' => 515,
		'FILTER_SANITIZE_EMAIL' => 517,
		'FILTER_SANITIZE_URL' => 518,
		'FILTER_SANITIZE_NUMBER_INT' => 519,
		'FILTER_SANITIZE_NUMBER_FLOAT' => 520,
		'FILTER_SANITIZE_MAGIC_QUOTES' => 521,
		'FILTER_CALLBACK' => 1024,
		'FILTER_FLAG_ALLOW_OCTAL' => 1,
		'FILTER_FLAG_ALLOW_HEX' => 2,
		'FILTER_FLAG_STRIP_LOW' => 4,
		'FILTER_FLAG_STRIP_HIGH' => 8,
		'FILTER_FLAG_ENCODE_LOW' => 16,
		'FILTER_FLAG_ENCODE_HIGH' => 32,
		'FILTER_FLAG_ENCODE_AMP' => 64,
		'FILTER_FLAG_NO_ENCODE_QUOTES' => 128,
		'FILTER_FLAG_EMPTY_STRING_NULL' => 256,
		'FILTER_FLAG_ALLOW_FRACTION' => 4096,
		'FILTER_FLAG_ALLOW_THOUSAND' => 8192,
		'FILTER_FLAG_ALLOW_SCIENTIFIC' => 16384,
		'FILTER_FLAG_SCHEME_REQUIRED' => 65536,
		'FILTER_FLAG_HOST_REQUIRED' => 131072,
		'FILTER_FLAG_PATH_REQUIRED' => 262144,
		'FILTER_FLAG_QUERY_REQUIRED' => 524288,
		'FILTER_FLAG_IPV4' => 1048576,
		'FILTER_FLAG_IPV6' => 2097152,
		'FILTER_FLAG_NO_RES_RANGE' => 4194304,
		'FILTER_FLAG_NO_PRIV_RANGE' => 8388608,
	);

	foreach ($constants as $constant => $value)
		if (!defined($constant))
			define($constant, $value);
}

function filter_var ($variable, $filter = FILTER_SANITIZE_STRING, $user_options = false)
{
	// Setup a default filter.
	$filter = $filter === false ? FILTER_SANITIZE_STRING : $filter;

	// Maybe we have some flags/options.
	if (!empty($user_options)
	{
		$options = !empty($user_options['options']) ? &$user_options['options'] : null;
		$flags = !empty($user_options['flags']) ? &$user_options['flags'] : null;;
	}

	switch ($filter)
	{
		// Validates value as integer, optionally from the specified range.
		case FILTER_VALIDATE_INT:
			$filter_flags = array(FILTER_FLAG_ALLOW_OCTAL, FILTER_FLAG_ALLOW_HEX);
			$filter_options = array('min_range', 'max_range');

			if (isset($options['max_range']))
				$variable = min($options['max_range'], $variable);
			if (isset($options['min_range']))
				$variable = max($options['min_range'], $variable);

			break;

		// Returns TRUE for "1", "true", "on" and "yes", FALSE for "0", "false", "off", "no", and "", NULL otherwise.
		case FILTER_VALIDATE_BOOLEAN:
			if (in_array($variable, array(1, true, 'on', 'yes')))
				$variable = true;
			elseif (in_array($variable, array(0, false, 'off', 'no', '')))
				$variable = false;
			else
				$variable = null;

			break;

		// Validates value as float.
		case FILTER_VALIDATE_FLOAT:
			$variable = is_float($variable);

			break;

		// Validates value against regexp, a Perl-compatible regular expression.
		case FILTER_VALIDATE_REGEXP:
			$filter_options = array('regexp');
			// !!! Not implemented yet.

			break;

		// Validates value as URL, optionally with required components.
		case FILTER_VALIDATE_URL:
			$filter_flags = array(FILTER_FLAG_SCHEME_REQUIRED, FILTER_FLAG_HOST_REQUIRED, FILTER_FLAG_PATH_REQUIRED, FILTER_FLAG_QUERY_REQUIRED);
			
			break;

		// Validates value as IP address, optionally only IPv4 or IPv6 or not from private or reserved ranges.
		case FILTER_VALIDATE_IP:
			$filter_flags = array(FILTER_FLAG_IPV4, FILTER_FLAG_IPV6, FILTER_FLAG_NO_PRIV_RANGE, FILTER_FLAG_NO_RES_RANGE);
			
			break;

		// Strip tags, optionally strip or encode special characters.
		case FILTER_SANITIZE_STRING:
			$filter_flags = array(FILTER_FLAG_NO_ENCODE_QUOTES, FILTER_FLAG_STRIP_LOW, FILTER_FLAG_STRIP_HIGH, FILTER_FLAG_ENCODE_LOW, FILTER_FLAG_ENCODE_HIGH, FILTER_FLAG_ENCODE_AMP);
			
			break;

		// Alias of "string" filter.
		case FILTER_SANITIZE_STRIPPED:
			
			break;

		// URL-encode string, optionally strip or encode special characters.
		case FILTER_SANITIZE_ENCODED:
			$filter_flags = array(FILTER_FLAG_STRIP_LOW, FILTER_FLAG_STRIP_HIGH, FILTER_FLAG_ENCODE_LOW, FILTER_FLAG_ENCODE_HIGH);
			
			break;

		// HTML-escape '"<>& and characters with ASCII value less than 32, optionally strip or encode other special characters.
		case FILTER_SANITIZE_SPECIAL_CHARS:
			$filter_flags = array(FILTER_FLAG_STRIP_LOW, FILTER_FLAG_STRIP_HIGH, FILTER_FLAG_ENCODE_HIGH);
			
			break;

		// Do nothing, optionally strip or encode special characters.
		case FILTER_UNSAFE_RAW:
			$filter_flags = array(FILTER_FLAG_STRIP_LOW, FILTER_FLAG_STRIP_HIGH, FILTER_FLAG_ENCODE_LOW, FILTER_FLAG_ENCODE_HIGH, FILTER_FLAG_ENCODE_AMP);
			
			break;

		// Remove all characters except letters, digits and !#$%&'*+-/=?^_`{|}~@.[].
		case FILTER_SANITIZE_EMAIL:
		// Validates value as e-mail.
		case FILTER_VALIDATE_EMAIL:
			// Break this up in to a domain and a user
			$email = explode('@', $variable);

			// There has to be two parts to an email.
			if (count($email) != 2)
			{
				$variable = null;
				break;
			}

			// Remove the bad stuff from this email.
			if ($filter == FILTER_SANITIZE_EMAIL)
				$email = preg_replace('/[^a-zA-Z0-9!#$%&\\\'*+\\-\/=?^_`{|}~.\\[\\]]+/', '', $email);

			// Emails can't be larger than {64}@{255}
			if (count($email[0]) > 64 || count($email[0]) < 1 || count($email[1]) > 255 || count($email[1]) < 4)
			{
				$variable = null;
				break;
			}

			$variable = implode('@', $email);
			break;

		// Remove all characters except letters, digits and $-_.+!*'(),{}|\\^~[]`<>#%";/?:@&=.
		case FILTER_SANITIZE_URL:
			// Maybe it is supposed to be [^a-zA-Z0-9\\$-_\\.\\+\\!\\*\'\\(\\),\\{\\}\\|\\\\\\^~\\[\\]`\\<\\>#%\";/\\?\\:@&\\=]+
			$variable = preg_replace('/[^a-zA-Z0-9$\\-_.+!*\'(),{}|\\\\^~\\[\\]`<>#%";\/?:@&=]+/', '', $variable);
			
			$

			break;

		// Remove all characters except digits and +-.
		case FILTER_SANITIZE_NUMBER_INT:
			$variable = preg_replace('/[^\d+\-]+/', '', $variable);

			break;

		// Remove all characters except digits, +- and optionally .,eE.
		case FILTER_SANITIZE_NUMBER_FLOAT:
			$filter_flags = array(FILTER_FLAG_ALLOW_FRACTION, FILTER_FLAG_ALLOW_THOUSAND, FILTER_FLAG_ALLOW_SCIENTIFIC);
			
			$variable = preg_replace('/[^\d+\-\.,eE]+/', '', $variable);

			break;

		// Apply addslashes().
		case FILTER_SANITIZE_MAGIC_QUOTES:
			$variable = addslashes($variable);

			break;

		// Call user-defined function to filter data.
		case FILTER_CALLBACK:
			$variable = call_user_func($variable);

			break;
	}

	return $variable;
}
?>