A simple class for handling URL strings for links.

class.urlstring.php

<?php
class urlstring {
  private $params = array();

	function __construct() {
		// Pulling parameters from the URL string.
		$str = explode("&",$_SERVER['QUERY_STRING']);
		foreach ($str as $item) {
			$split = explode("=",$item);
			$this->params[$split[0]] = $split[1];
		}
	}

	/* ~~~~~~~~~~~~~~~
	   ~~~ Setters ~~~
	   ~~~~~~~~~~~~~~~ */
	// Set a single parameter & value.
	public function set_parameter($name, $value) {
		$this->params[$name] = $value;
	}

	// Set multiple parameters / values at a time.
		// $data should be an associative array.
	public function set_parameters($data = array()) {
		if (is_array($data)) {
			foreach ($data as $name=>$value) {
				$this->params[$name] = $value;
			}
		}
	}

	/* ~~~~~~~~~~~~~~~
	   ~~~ Getters ~~~
	   ~~~~~~~~~~~~~~~ */
	// Returns a URL string with all string parameters.
	public function get_string($prefix = false) {
		$str = "";
		foreach ($this->params as $name=>$value) {
			$str .= $name."=".$value."&";
		}
		$str = rtrim($str,"&");
		if ($prefix) {
			$str = "?".$str;
		}
		return $str;
	}

	// Returns a URL string with all string parameters and a one-time modified data set.
		// $data should be an associative array.
	public function get_modded_string($data = array(), $prefix = false) {
		$params = $this->params;
		if (is_array($data)) {
			foreach ($data as $name=>$value) {
				$params[$name] = $value;
			}
		}
		$str = "";
		foreach ($params as $name=>$value) {
			$str .= $name."=".$value."&";
		}
		$str = rtrim($str,"&");
		if ($prefix) {
			$str = "?".$str;
		}
		return $str;
	}

	/* ~~~~~~~~~~~~~~~
	   ~~~ Helpers ~~~
	   ~~~~~~~~~~~~~~~ */

}
?>