upgrade.php

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<?php
/**
 * api:		php
 * title:	WentPHP5 / upgrade.php
 * description:	Emulates functions from new PHP versions on older interpreters.
 * version:	15
 * license:	Public Domain
 * url:		http://freshmeat.net/p/upgradephp
 * type:	functions
 * category:	library
 * priority:	auto
 * sort:	-255
 * provides:	upgrade-php, api:php5
 *
 *
 * By loading this library you get PHP version independence. It provides
 * downwards compatibility to older PHP interpreters by emulating missing
 * functions or constants using IDENTICAL NAMES. So this doesn't slow down
 * script execution on setups where the native functions already exist. It
 * is meant as quick drop-in solution. It spares you from rewriting code or
 * using cumbersome workarounds, instead of the more powerful v5 functions.
 * 
 * It cannot mirror PHP5s extended OO-semantics and functionality into PHP4
 * however. A few features are added here that weren't part of PHP yet. And
 * some other function collections are separated out into the ext/ directory.
 * It doesn't produce many custom error messages (YAGNI), and instead leaves
 * reporting to invoked functions or for execution on native PHP.
 * 
 * And further this is PUBLIC DOMAIN (no copyright, no license, no warranty)
 * so therefore compatible to ALL open source licenses. You could rip this
 * paragraph out to republish this instead only under more restrictive terms
 * or your favorite license (GNU LGPL/GPL, BSDL, MPL/CDDL, Artistic/PHPL, ..)
 *
 * Any contribution is appreciated. <milky*users#sf#net>
 *
 */


/**
 *                                   ------------------------------ 5.2 ---
 * @group 5_2
 * @since 5.2
 *
 * Additions of PHP 5.2.0
 * - some listed here might have appeared earlier or in release candidates
 *
 * @emulated
 *    json_encode
 *    json_decode
 *    error_get_last
 *    preg_last_error
 *    lchown
 *    lchgrp
 *    E_RECOVERABLE_ERROR
 *    M_SQRTPI
 *    M_LNPI
 *    M_EULER
 *    M_SQRT3
 *
 * @missing
 *    sys_getloadavg
 *    inet_ntop
 *    inet_pton
 *    array_fill_keys
 *    array_intersect_key
 *    array_intersect_ukey
 *    array_diff_key
 *    array_diff_ukey
 *    array_product
 *    pdo_drivers
 *    ftp_ssl_connect
 *    XmlReader
 *    XmlWriter
 *    PDO*
 *
 * @unimplementable
 *    stream_*
 *
 */



/**
 * @since unknown
 */
if (!defined("E_RECOVERABLE_ERROR")) { define("E_RECOVERABLE_ERROR", 4096); }



/**
 * Converts PHP variable or array into a "JSON" (JavaScript value expression
 * or "object notation") string.
 *
 * @compat
 *    Output seems identical to PECL versions. "Only" 20x slower than PECL version.
 * @bugs
 *    Doesn't take care with unicode too much - leaves UTF-8 sequences alone.
 *
 * @param  $var mixed  PHP variable/array/object
 * @return string      transformed into JSON equivalent
 */
if (!function_exists("json_encode")) {
   function json_encode($var, /*emu_args*/$obj=FALSE) {
   
      #-- prepare JSON string
      $json = "";
      
      #-- add array entries
      if (is_array($var) || ($obj=is_object($var))) {

         #-- check if array is associative
         if (!$obj) foreach ((array)$var as $i=>$v) {
            if (!is_int($i)) {
               $obj = 1;
               break;
            }
         }

         #-- concat invidual entries
         foreach ((array)$var as $i=>$v) {
            $json .= ($json ? "," : "")    // comma separators
                   . ($obj ? ("\"$i\":") : "")   // assoc prefix
                   . (json_encode($v));    // value
         }

         #-- enclose into braces or brackets
         $json = $obj ? "{".$json."}" : "[".$json."]";
      }

      #-- strings need some care
      elseif (is_string($var)) {
         if (!utf8_decode($var)) {
            $var = utf8_encode($var);
         }
         $var = str_replace(array("\"", "\\", "/", "\b", "\f", "\n", "\r", "\t"), array("\\\"", "\\\\", "\\/", "\\b", "\\f", "\\n", "\\r", "\\t"), $var);
         $json = '"' . $var . '"';
         //@COMPAT: for fully-fully-compliance   $var = preg_replace("/[\000-\037]/", "", $var);
      }

      #-- basic types
      elseif (is_bool($var)) {
         $json = $var ? "true" : "false";
      }
      elseif ($var === NULL) {
         $json = "null";
      }
      elseif (is_int($var) || is_float($var)) {
         $json = "$var";
      }

      #-- something went wrong
      else {
         trigger_error("json_encode: don't know what a '" .gettype($var). "' is.", E_USER_ERROR);
      }
      
      #-- done
      return($json);
   }
}



/**
 * Parses a JSON (JavaScript value expression) string into a PHP variable
 * (array or object).
 *
 * @compat
 *    Behaves similar to PECL version, but is less quiet on errors.
 *    Now even decodes unicode \uXXXX string escapes into UTF-8.
 *    "Only" 27 times slower than native function.
 * @bugs
 *    Might parse some misformed representations, when other implementations
 *    would scream error or explode.
 * @code
 *    This is state machine spaghetti code. Needs the extranous parameters to
 *    process subarrays, etc. When it recursively calls itself, $n is the
 *    current position, and $waitfor a string with possible end-tokens.
 *
 * @param   $json string   JSON encoded values
 * @param   $assoc bool    (optional) if outer shell should be decoded as object always
 * @return  mixed          parsed into PHP variable/array/object
 */
if (!function_exists("json_decode")) {
   function json_decode($json, $assoc=FALSE, /*emu_args*/$n=0,$state=0,$waitfor=0) {

      #-- result var
      $val = NULL;
      static $lang_eq = array("true" => TRUE, "false" => FALSE, "null" => NULL);
      static $str_eq = array("n"=>"\012", "r"=>"\015", "\\"=>"\\", '"'=>'"', "f"=>"\f", "b"=>"\b", "t"=>"\t", "/"=>"/");

      #-- flat char-wise parsing
      for (/*n*/; $n<strlen($json); /*n*/) {
         $c = $json[$n];

         #-= in-string
         if ($state==='"') {

            if ($c == '\\') {
               $c = $json[++$n];
               // simple C escapes
               if (isset($str_eq[$c])) {
                  $val .= $str_eq[$c];
               }

               // here we transform \uXXXX Unicode (always 4 nibbles) references to UTF-8
               elseif ($c == "u") {
                  // read just 16bit (therefore value can't be negative)
                  $hex = hexdec( substr($json, $n+1, 4) );
                  $n += 4;
                  // Unicode ranges
                  if ($hex < 0x80) {    // plain ASCII character
                     $val .= chr($hex);
                  }
                  elseif ($hex < 0x800) {   // 110xxxxx 10xxxxxx 
                     $val .= chr(0xC0 + $hex>>6) . chr(0x80 + $hex&63);
                  }
                  elseif ($hex <= 0xFFFF) { // 1110xxxx 10xxxxxx 10xxxxxx 
                     $val .= chr(0xE0 + $hex>>12) . chr(0x80 + ($hex>>6)&63) . chr(0x80 + $hex&63);
                  }
                  // other ranges, like 0x1FFFFF=0xF0, 0x3FFFFFF=0xF8 and 0x7FFFFFFF=0xFC do not apply
               }

               // no escape, just a redundant backslash
               //@COMPAT: we could throw an exception here
               else {
                  $val .= "\\" . $c;
               }
            }

            // end of string
            elseif ($c == '"') {
               $state = 0;
            }

            // yeeha! a single character found!!!!1!
            else/*if (ord($c) >= 32)*/ { //@COMPAT: specialchars check - but native json doesn't do it?
               $val .= $c;
            }
         }

         #-> end of sub-call (array/object)
         elseif ($waitfor && (strpos($waitfor, $c) !== false)) {
            return array($val, $n);  // return current value and state
         }
         
         #-= in-array
         elseif ($state===']') {
            list($v, $n) = json_decode($json, 0, $n, 0, ",]");
            $val[] = $v;
            if ($json[$n] == "]") { return array($val, $n); }
         }

         #-= in-object
         elseif ($state==='}') {
            list($i, $n) = json_decode($json, 0, $n, 0, ":");   // this allowed non-string indicies
            list($v, $n) = json_decode($json, 0, $n+1, 0, ",}");
            $val[$i] = $v;
            if ($json[$n] == "}") { return array($val, $n); }
         }

         #-- looking for next item (0)
         else {
         
            #-> whitespace
            if (preg_match("/\s/", $c)) {
               // skip
            }

            #-> string begin
            elseif ($c == '"') {
               $state = '"';
            }

            #-> object
            elseif ($c == "{") {
               list($val, $n) = json_decode($json, $assoc, $n+1, '}', "}");
               if ($val && $n && !$assoc) {
                  $obj = new stdClass();
                  foreach ($val as $i=>$v) {
                     $obj->{$i} = $v;
                  }
                  $val = $obj;
                  unset($obj);
               }
            }
            #-> array
            elseif ($c == "[") {
               list($val, $n) = json_decode($json, $assoc, $n+1, ']', "]");
            }

            #-> comment
            elseif (($c == "/") && ($json[$n+1]=="*")) {
               // just find end, skip over
               ($n = strpos($json, "*/", $n+1)) or ($n = strlen($json));
            }

            #-> numbers
            elseif (preg_match("#^(-?\d+(?:\.\d+)?)(?:[eE]([-+]?\d+))?#", substr($json, $n), $uu)) {
               $val = $uu[1];
               $n += strlen($uu[0]) - 1;
               if (strpos($val, ".")) {  // float
                  $val = (float)$val;
               }
               elseif ($val[0] == "0") {  // oct
                  $val = octdec($val);
               }
               else {
                  $val = (int)$val;
               }
               // exponent?
               if (isset($uu[2])) {
                  $val *= pow(10, (int)$uu[2]);
               }
            }

            #-> boolean or null
            elseif (preg_match("#^(true|false|null)\b#", substr($json, $n), $uu)) {
               $val = $lang_eq[$uu[1]];
               $n += strlen($uu[1]) - 1;
            }

            #-- parsing error
            else {
               // PHPs native json_decode() breaks here usually and QUIETLY
              trigger_error("json_decode: error parsing '$c' at position $n", E_USER_WARNING);
               return $waitfor ? array(NULL, 1<<30) : NULL;
            }

         }//state
         
         #-- next char
         if ($n === NULL) { return NULL; }
         $n++;
      }//for

      #-- final result
      return ($val);
   }
}



/**
 * Constants for future 64-bit integer support.
 *
 */
if (!defined("PHP_INT_SIZE")) { define("PHP_INT_SIZE", 4); }
if (!defined("PHP_INT_MAX")) { define("PHP_INT_MAX", 2147483647); }



/**
 * @flag bugfix
 * @see #33895
 *
 * Missing constants in 5.1, originally appeared in 4.0.
 */
if (!defined("M_SQRTPI")) { define("M_SQRTPI", 1.7724538509055); }
if (!defined("M_LNPI")) { define("M_LNPI", 1.1447298858494); }
if (!defined("M_EULER")) { define("M_EULER", 0.57721566490153); }
if (!defined("M_SQRT3")) { define("M_SQRT3", 1.7320508075689); }




/**
 * removes entities &lt; &gt; &amp; and eventually &quot; from HTML string
 *
 */
if (!function_exists("htmlspecialchars_decode")) {
   if (!defined("ENT_COMPAT")) { define("ENT_COMPAT", 2); }
   if (!defined("ENT_QUOTES")) { define("ENT_QUOTES", 3); }
   if (!defined("ENT_NOQUOTES")) { define("ENT_NOQUOTES", 0); }
   function htmlspecialchars_decode($string, $quotes=2) {
      $d = $quotes & ENT_COMPAT;
      $s = $quotes & ENT_QUOTES;
      return str_replace(
         array("&lt;", "&gt;", ($s ? "&quot;" : "&.-;"), ($d ? "&#039;" : "&.-;"), "&amp;"),
         array("<",    ">",    "'",                      "\"",                     "&"),
         $string
      );
   }
}



?>