<A Basic PHP StringBuilder ⁄ >

<?php
 
/**
 * Class StringBuilder
 * 
 * This class tries to emulate a simple StringBuilder
 *
 * @author pedrocorreia.net
 */
class StringBuilder{
  private $_result;
 
  /**
   * Constructor
   *
   */
  public function __construct(){$this->_result=array();}
 
  /**
   * Destructor
   *
   */
  public function __destruct(){$this->_ClearElements();}
 
  /**
   * Append Line
   *
   * @param String
   */
  public function Append($value){$this->_AddElement($value);}
 
  /**
   * Append Line including "\n" at the beginning
   *
   * @param String
   */
  public function AppendLine($value){$this->_AddElement("\r\n$value");}
 
  /**
   * Insert element at a specific position
   *
   * @param Int Position
   * @param String value
   */
  public function Insert($pos, $value){$this->_AddElement($value,$pos-1);}
 
  /**
   * Switch Elements
   *
   * @param Int 1st Position
   * @param Int 2nd Position
   */
  public function Exchange($from, $to){$this->_SwitchElements($from-1,$to-1);}
 
  /**
   * Update Element
   *
   * @param String Value
   * @param Int Position
   */
  public function Update($value,$pos){$this->_UpdateElement($pos-1,$value);}
 
  /**
   * Replace Element (Alias of Update)
   *
   * @param Int Position
   * @param String
   */
  public function Replace($pos,$value){$this->Update($value,$pos);}
 
  /**
   * Get number of Elements
   *
   * @return Int
   */
  public function Count(){return sizeof($this->_result);}
 
  /**
   * Get total String Length
   *
   * @return Int
   */
  public function Length(){
    $count=$this->Count();
    $sum=0;
    for($i=0;$i<$count;$i++){
      $sum+=strlen($this->_GetElement($i));
    }
 
    return $sum;
  }
 
  /**
   * Get specific Element
   *
   * @param Int Position
   * @return String
   */
  public function Element($pos){
    try{$elem=$this->_GetElement($pos-1);}
    catch (Exception $ex){$elem="Exception: $ex";}
 
    return $elem;
  }
 
  /**
   * Remove element
   *
   * @param Int Position
   * @return Bool
   */
  public function Remove($pos){
    $res=true;
    try{$this->_RemoveElement($pos-1);}
    catch (Exception $ex){$res=false;}
    return $res;
  }
 
  /**
   * Clear all elements
   *
   */
  public function Clear(){$this->_ClearElements();}
 
  /**
   * Convert StringBuilder to String
   *
   * @return String
   */
  public function ToString(){
    $count=$this->Count();
    for($i=0;$i<$count;$i++){
      $str.=nl2br($this->_GetElement($i));
    }
 
    return $str;
  }
 
  /**
   * Add/ Insert Element
   *
   * @param String
   * @param Int [Optional] Insert element at specific index
   * 
   * note: when inserting element at specific index, if that index's 
   * bigger than Elements Count, or invalid, i.e., 
   * negative or and inexistent index; 
   * the value will be appended
   */
  private function _AddElement($value,$pos=null){
    if(!is_numeric($pos)){
      $this->_result[]=$value;
    }
    else{
      if(!$this->_IsValidIndex($pos)) $pos=$this->Count();
      array_splice($this->_result,$pos,0,$value);
    }
  }
 
  /**
   * Update Element
   *
   * @param Int Index
   * @param String Value
   */
  private function _UpdateElement($pos,$value){
    if(!$this->_IsValidIndex($pos)) throw new Exception("OUT_OF_BOUNDS");
    $this->_result[$pos]=$value;
  }
 
  /**
   * Get Element
   *
   * @param Int Index
   * @return String
   */
  private function _GetElement($pos){
    if(!$this->_IsValidIndex($pos)) throw new Exception("OUT_OF_BOUNDS");
    return $this->_result[$pos];
  }
 
  /**
   * Remove Element
   *
   * @param Int Index
   */
  private function _RemoveElement($pos){
    if(!$this->_IsValidIndex($pos)) throw new Exception("OUT_OF_BOUNDS");
    unset($this->_result[$pos]);
    $this->_result=array_values($this->_result);
  }
 
  /**
   * Switch Elements
   *
   * @param Int 1st Index
   * @param Int 2nd Index
   */
  private function _SwitchElements($pos1,$pos2){
    if(!$this->_IsValidIndex($pos1) || !$this->_IsValidIndex($pos2)){
      throw new Exception("OUT_OF_BOUNDS");
    }
    $aux=$this->_GetElement($pos2);
    $this->_result[$pos2]=$this->_GetElement($pos1);
    $this->_result[$pos1]=$aux;
  }
 
  /**
   * Clear StringBuilder
   *
   */
  private function _ClearElements(){unset($this->_result);}
 
  /**
   * Check if the index is valid
   *
   * @param Int Index to examine
   * @return Bool
   */
  private function _IsValidIndex($num){
    return ($num<$this->Count() && $num>=0);
  }
 
}
?>

<?php
include_once("class.StringBuilder.php");
 
$str=new StringBuilder();
 
$str->Append(1);
$str->Append(2);
$str->Append(3);
echo $str->ToString();
 
echo "<br/>__________<br/>";
$str->Insert(1,0);
$str->Insert(5,4);
echo $str->ToString();
 
echo "<br/>__________<br/>";
$str->Replace(1,"Hello I replaced the Value '0'. ");
echo $str->ToString();
 
echo "<br/>__________<br/>";
echo "String Length: {$str->Length()} chars";
 
echo "<br/>__________<br/>";
$str->Remove(2);
echo $str->ToString();
 
echo "<br/>__________<br/>";
$str->Exchange(2,3);
echo $str->ToString();
 
echo "<br/>__________<br/>";
$str->Update(". Change the last element to this new text",$str->Count());
echo $str->ToString();
 
echo "<br/>__________<br/>";
$str->AppendLine("... And I add a new line...");
echo $str->ToString();
 
echo "<br/>__________<br/>";
$i=4;
echo "{$i}th Element={$str->Element($i)}";
 
echo "<br/>__________<br/>";
$str->Clear();
//won't output anything, because we didn't
//add elements since last Clear()
echo $str->ToString();
?>