<?php

/**
 * Parses a URI into the components and fragment identifier as specified
 * by RFC 3986.
 */
class HTMLPurifier_URIParser {
	
	/**
	 * Instance of HTMLPurifier_PercentEncoder to do normalization with.
	 */
	protected $percentEncoder;
	public function __construct() {
		$this->percentEncoder = new HTMLPurifier_PercentEncoder ();
	}
	
	/**
	 * Parses a URI.
	 * 
	 * @param $uri string
	 *        	URI to parse
	 * @return HTMLPurifier_URI representation of URI. This representation has
	 *         not been validated yet and may not conform to RFC.
	 */
	public function parse($uri) {
		$uri = $this->percentEncoder->normalize ( $uri );
		
		// Regexp is as per Appendix B.
		// Note that ["<>] are an addition to the RFC's recommended
		// characters, because they represent external delimeters.
		$r_URI = '!' . '(([a-zA-Z0-9\.\+\-]+):)?' . // 2. Scheme
'(//([^/?#"<>]*))?' . // 4. Authority
'([^?#"<>]*)' . // 5. Path
'(\?([^#"<>]*))?' . // 7. Query
'(#([^"<>]*))?' . // 8. Fragment
'!';
		
		$matches = array ();
		$result = preg_match ( $r_URI, $uri, $matches );
		
		if (! $result)
			return false; // *really* invalid URI
				                            
		// seperate out parts
		$scheme = ! empty ( $matches [1] ) ? $matches [2] : null;
		$authority = ! empty ( $matches [3] ) ? $matches [4] : null;
		$path = $matches [5]; // always present, can be empty
		$query = ! empty ( $matches [6] ) ? $matches [7] : null;
		$fragment = ! empty ( $matches [8] ) ? $matches [9] : null;
		
		// further parse authority
		if ($authority !== null) {
			$r_authority = "/^((.+?)@)?(\[[^\]]+\]|[^:]*)(:(\d*))?/";
			$matches = array ();
			preg_match ( $r_authority, $authority, $matches );
			$userinfo = ! empty ( $matches [1] ) ? $matches [2] : null;
			$host = ! empty ( $matches [3] ) ? $matches [3] : '';
			$port = ! empty ( $matches [4] ) ? ( int ) $matches [5] : null;
		} else {
			$port = $host = $userinfo = null;
		}
		
		return new HTMLPurifier_URI ( $scheme, $userinfo, $host, $port, $path, $query, $fragment );
	}
}

// vim: et sw=4 sts=4