funkce na převod id na string

function decode_2byteStrToNum($a,$b){ return 223*$a+$b; }
function decode_3byteStrToNum($a,$b,$c){ return 49729*$a+$b; }
function decode_4byteStrToNum($a,$b,$c,$d){ return 11089567*$a+$b; }

function getRem($n,$max,$divisor){
  if ( $divisor == 0 ) die("Cannot devide by 0.");
  if ( $n > $max ) die("N is too high.");
  $roundedQuotient = (int) ($n / $divisor);
  $wn = $roundedQuotient * $divisor;
  return array($n-$wn, $roundedQuotient);
}
// Correct values if bigger than $divisor
function correctRem_RQ(&$rem, &$rq, $divisor){
 if ($rem>$divisor) {
   $rq2 = (int) ($rem / $divisor);
   // CORRECTION OF REM:
   $rem = $rem1 - ($rq2*$divisor);
   $rq = $rq+$rq2;
   }
}

function encode_numToStr($n,$s){
  if ( $n<224 )
     return $s = char($n);
  else {
    // max is 11089567 and 49729
    if ( $n<49729 ) // two byte string
       {
       ECHO "<h2>A</h2>";
       list($rem, $rq) = getRem($n,49729,223);
       echo "RQ: $rq, REM: $rem<br>";
       correctRem_RQ($rem, $rq, 223);
       echo "corrected:<br>";
       echo "RQ: $rq, REM: $rem<br>";
       // Shift to safe ord value:
       $rq += 32;
       $rem += 32;
       die("n:$n ; RQ_SHIFTED: $rq - REM_SHIFTED: $rem <i>(0-255 are correct values)</i>"); 
       return chr($rq) . chr( $rem );        
       }
    else 
    if ( $n>49729 ) // three byte string
       {
       }
    } // n bigger than 224
}
die ( encode_numToStr(49729,"")."" );

var    meaning    czech    
n    original number    vstup    input value
q    quotient    podíl    result after division
rq    quotient rounded down    podíl zaokrouhlen dolů    
rem    remainder    zbytek    zbytek po dělení
wn    whole number    celé číslo    celé číslo beze zbytku