PHP downwards compatibility functions
-------------------------------------
The "upgrade.php" package implements features and functions from
newer PHP versions. It defines them as pure PHP code. Functions
get defined dynamically, at runtime. All emulated functions use
names identical to the original implementation. But won't perturb
if the native functions exist.

So this is really a drop-in replacement. It allows you to use most
PHP features regardless of the current PHP interpreter. You just
have to include() this single script to remove any backward
compatibility woes.
This allows relying on the newer, more powerful PHP functions. Use
and retyping of workarounds gets superfluous.



this is useful:

- for open source distributions
- if your own providers PHP version is immemorial
- you want to test new functions, but not install a new PHP ver

interpreter release:

  <?example
     if (PHP_VERSION < "5.4.0") { include(".../upgrade.php"); }
  ?>

Currently following functions can be emulated:
· array_column
· json_last_error_msg
· boolval
· json_encode
· json_decode
· strptime
· gzdecode
· htmlspecialchars_decode
· fputcsv
· ob_get_headers

v19
  - Adds new PHP5.5 functions: array_column(), json_last_error_msg(),
    boolval()
  - Ships with password_compat[MITL] from Anthony Ferrara, which add
    password_hash() and password_verify() from PHP5.5
  - Minor additions to json_encode and json_decode
  - Introduces ext/contrib/pdo_mysql.php, wrapper functions for PDO,
    that mimick the signature of mysql_* functions with a pdo_* prefix.

v18
  - Anthon Pang contributed mysqli_set_charset() and E_DEPRECATED const
  - Also contrib/safe_serialize and unserialize() implementations by Anthon
  - TMPDIR support for sys_get_temp_dir()
  - gzdecode is now an official PHP 5.4 function.
  - hex2bin

<?php
 /**
  * api: php
  * title: Input $_REQUEST wrappers
  * type: interface
  * description: provides sanitization by encapsulating request superglobals against raw access
  * version: 2.6
  * revision: $Id$
  * license: Public Domain
  * depends: php:filter, php >5.0, html_purifier
  * config: <const name="INPUT_DIRECT" type="multi" value="disallow" multi="disallow|raw|log" description="filter method for direct $_REQUEST[var] access" />
  *         <const name="INPUT_QUIET" type="bool" value="0" multi="0=report all|1=no notices|2=no warnings" description="suppress access and behaviour notices" />
  * throws: E_USER_NOTICE, E_USER_WARNING, OutOfBoundsException
  *

  *   ->log
  *   ->raw
  *
  * You can also pre-define a standard filter-chain for all following calls:
  *   $_GET->nocontrol->iconv->utf7->xss->always();
  *
  * Using $__rules[] a set of filter rules can be preset per variable name.
  *
  * Parameterized filters can alternatively use the ellipsis … symbol (AltGr+:)
  * instead of the terminating method access syntax.
  *   $_GET->int->range…0…59["minutes"]
  *
  * Some filters are a mixture of sanitizing and validation. Basically
  * all can also be used independently of the superglobals with their
  * underscore name, $str = input::_text($str);
  *
  * For the superglobals it's also possible to count($_GET); or check with
  * just $_POST() if there are contents. (Use this in lieu of empty() test.)

     * [b]
     * Abort with fatal error. (Used as fallback for INPUT_DIRECT access.)
     *
     */
    function _disallow($data) {
        throw OutOfBoundsException("Direct \$_REQUEST[\"$this->__varname\"] is not allowed, add ->filter method, or change INPUT_DIRECT if needed.");
    }
    
    
    
    /**
     * Validate instead of sanitize.
     *
     */
    function _is($data) {
        $this->__filter[] = array("is_still", array());
        return $data;
    }
    function _is_still($data) {
        return $data === $this->__vars[$this->__varname];
    }



   

    ######  implementation  ################################################

     */
    function __get($filtername) {
        //
        // we could do some heuristic chaining here,
        // if the last entry in the ->attrib->attrib list is not a valid method name,
        // but a valid varname, we should execute the filter chain rather than add.
        //
        
        // Unpack parameterized filter attributes, use U+2022 ellipsis … as delimiter
        if (strpos($filtername, "…")) {
            $args = explode("…", $filtername);
            $filtername = array_shift($args);
        }
        else {
            $args=array();
        }

        // Add filter to list
        $this->__filter[] = array($filtername, $args);

        // fluent interface
        return $this;
    }
    


    /**
     * @hide ArrayAccess
     *