xswitch/clients/flex/com/adobe/net/URI.as

/*
  Copyright (c) 2008, Adobe Systems Incorporated
  All rights reserved.

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  modification, are permitted provided that the following conditions are
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  IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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*/

package com.adobe.net
{
	import flash.utils.ByteArray;
	
	/**
	 * This class implements functions and utilities for working with URI's
	 * (Universal Resource Identifiers).  For technical description of the
	 * URI syntax, please see RFC 3986 at http://www.ietf.org/rfc/rfc3986.txt
	 * or do a web search for "rfc 3986".
	 * 
	 * <p>The most important aspect of URI's to understand is that URI's
	 * and URL's are not strings.  URI's are complex data structures that
	 * encapsulate many pieces of information.  The string version of a
	 * URI is the serialized representation of that data structure.  This
	 * string serialization is used to provide a human readable
	 * representation and a means to transport the data over the network
	 * where it can then be parsed back into its' component parts.</p>
	 * 
	 * <p>URI's fall into one of three categories:
	 * <ul>
	 *  <li>&lt;scheme&gt;:&lt;scheme-specific-part&gt;#&lt;fragment&gt;		(non-hierarchical)</li>
	 *  <li>&lt;scheme&gt;:<authority&gt;&lt;path&gt;?&lt;query&gt;#&lt;fragment&gt;	(hierarchical)</li>
	 *  <li>&lt;path&gt;?&lt;query&gt;#&lt;fragment&gt;						(relative hierarchical)</li>
	 * </ul></p>
	 * 
	 * <p>The query and fragment parts are optional.</p>
	 * 
	 * <p>This class supports both non-hierarchical and hierarchical URI's</p>
	 * 
	 * <p>This class is intended to be used "as-is" for the vast majority
	 * of common URI's.  However, if your application requires a custom
	 * URI syntax (e.g. custom query syntax or special handling of
	 * non-hierarchical URI's), this class can be fully subclassed.  If you
	 * intended to subclass URI, please see the source code for complete
	 * documentation on protected members and protected functions.</p>
	 * 
	 * @langversion ActionScript 3.0
	 * @playerversion Flash 9.0 
	 */
	public class URI
	{	
		// Here we define which characters must be escaped for each
		// URI part.  The characters that must be escaped for each
		// part differ depending on what would cause ambiguous parsing.
		// RFC 3986 sec. 2.4 states that characters should only be
		// encoded when they would conflict with subcomponent delimiters.
		// We don't want to over-do the escaping.  We only want to escape
		// the minimum needed to prevent parsing problems.
		
		// space and % must be escaped in all cases.  '%' is the delimiter
		// for escaped characters.
		public static const URImustEscape:String =	" %";
		
		// Baseline of what characters must be escaped
		public static const URIbaselineEscape:String = URImustEscape + ":?#/@";
		
		// Characters that must be escaped in the part part.
		public static const URIpathEscape:String = URImustEscape + "?#";
		
		// Characters that must be escaped in the query part, if setting
		// the query as a whole string.  If the query is set by
		// name/value, URIqueryPartEscape is used instead.
		public static const URIqueryEscape:String = URImustEscape + "#";
		
		// This is what each name/value pair must escape "&=" as well
		// so they don't conflict with the "param=value&param2=value2"
		// syntax.
		public static const URIqueryPartEscape:String = URImustEscape + "#&=";
		
		// Non-hierarchical URI's can have query and fragment parts, but
		// we also want to prevent '/' otherwise it might end up looking
		// like a hierarchical URI to the parser.
		public static const URInonHierEscape:String = 	URImustEscape + "?#/";
		
		// Baseline uninitialized setting for the URI scheme.
		public static const UNKNOWN_SCHEME:String = "unknown";
		
		// The following bitmaps are used for performance enhanced
		// character escaping.
		
		// Baseline characters that need to be escaped.  Many parts use
		// this.
		protected static const URIbaselineExcludedBitmap:URIEncodingBitmap =
			new URIEncodingBitmap(URIbaselineEscape);
		
		// Scheme escaping bitmap
		protected static const URIschemeExcludedBitmap:URIEncodingBitmap = 
			URIbaselineExcludedBitmap;
		
		// User/pass escaping bitmap
		protected static const URIuserpassExcludedBitmap:URIEncodingBitmap =
			URIbaselineExcludedBitmap;
		
		// Authority escaping bitmap
		protected static const URIauthorityExcludedBitmap:URIEncodingBitmap =
			URIbaselineExcludedBitmap;
			
		// Port escaping bitmap
		protected static const URIportExludedBitmap:URIEncodingBitmap = 
			URIbaselineExcludedBitmap;
		
		// Path escaping bitmap
		protected static const URIpathExcludedBitmap:URIEncodingBitmap =
		 	new URIEncodingBitmap(URIpathEscape);
			
		// Query (whole) escaping bitmap
		protected static const URIqueryExcludedBitmap:URIEncodingBitmap =
			new URIEncodingBitmap(URIqueryEscape);
			
		// Query (individual parts) escaping bitmap
		protected static const URIqueryPartExcludedBitmap:URIEncodingBitmap =
			new URIEncodingBitmap(URIqueryPartEscape);
			
		// Fragments are the last part in the URI.  They only need to
		// escape space, '#', and '%'.  Turns out that is what query
		// uses too.
		protected static const URIfragmentExcludedBitmap:URIEncodingBitmap =
			URIqueryExcludedBitmap;
			
		// Characters that need to be escaped in the non-hierarchical part
		protected static const URInonHierexcludedBitmap:URIEncodingBitmap =
			new URIEncodingBitmap(URInonHierEscape);
			
		// Values used by getRelation()
		public static const NOT_RELATED:int = 0;
		public static const CHILD:int = 1;
		public static const EQUAL:int = 2;
		public static const PARENT:int = 3;

		//-------------------------------------------------------------------
		// protected class members
		//-------------------------------------------------------------------
		protected var _valid:Boolean = false;
		protected var _relative:Boolean = false;
		protected var _scheme:String = "";
		protected var _authority:String = "";
		protected var _username:String = "";
		protected var _password:String = "";
		protected var _port:String = "";
		protected var _path:String = "";
		protected var _query:String = "";
		protected var _fragment:String = "";
		protected var _nonHierarchical:String = "";
		protected static var _resolver:IURIResolver = null;


		/**
		 *  URI Constructor.  If no string is given, this will initialize
		 *  this URI object to a blank URI.
		 */
		public function URI(uri:String = null) : void	
		{
			if (uri == null)
				initialize();
			else
				constructURI(uri);
		}

		
		/**
		 * @private
		 * Method that loads the URI from the given string.
		 */
		protected function constructURI(uri:String) : Boolean
		{
			if (!parseURI(uri))
				_valid = false;
				
			return isValid();
		}
		
		
		/**
		 * @private Private initialization.
		 */
		protected function initialize() : void
		{
			_valid = false;
			_relative = false;
		
			_scheme = UNKNOWN_SCHEME;
			_authority = "";
			_username = "";
			_password = "";
			_port = "";
			_path = "";
			_query = "";
			_fragment = "";
		
			_nonHierarchical = "";
		}	
		
		/**
		 * @private Accessor to explicitly set/get the hierarchical
		 * state of the URI.
		 */
		protected function set hierState(state:Boolean) : void
		{
			if (state)
			{
				// Clear the non-hierarchical data
				_nonHierarchical = "";
		
				// Also set the state vars while we are at it
				if (_scheme == "" || _scheme == UNKNOWN_SCHEME)
					_relative = true;
				else
					_relative = false;
		
				if (_authority.length == 0 && _path.length == 0)
					_valid = false;
				else
					_valid = true;
			}
			else
			{
				// Clear the hierarchical data
				_authority = "";
				_username = "";
				_password = "";
				_port = "";
				_path = "";
		
				_relative = false;
		
				if (_scheme == "" || _scheme == UNKNOWN_SCHEME)
					_valid = false;
				else
					_valid = true;
			}
		}
		protected function get hierState() : Boolean
		{
			return (_nonHierarchical.length == 0);
		}
		
		
		/**
		 * @private Functions that performs some basic consistency validation.
		 */
		protected function validateURI() : Boolean
		{
			// Check the scheme
			if (isAbsolute())
			{
				if (_scheme.length <= 1 || _scheme == UNKNOWN_SCHEME)
				{
					// we probably parsed a C:\ type path or no scheme
					return false;
				}
				else if (verifyAlpha(_scheme) == false)
					return false;  // Scheme contains bad characters
			}
			
			if (hierState)
			{
				if (_path.search('\\') != -1)
					return false;  // local path
				else if (isRelative() == false && _scheme == UNKNOWN_SCHEME)
					return false;  // It's an absolute URI, but it has a bad scheme
			}
			else
			{
				if (_nonHierarchical.search('\\') != -1)
					return false;  // some kind of local path
			}
		
			// Looks like it's ok.
			return true;
		}
		
		
		/**
		 * @private
		 *
		 * Given a URI in string format, parse that sucker into its basic
		 * components and assign them to this object.  A URI is of the form:
		 *    <scheme>:<authority><path>?<query>#<fragment>
		 *
		 * For simplicity, we parse the URI in the following order:
		 * 		
		 *		1. Fragment (anchors)
		 * 		2. Query	(CGI stuff)
		 * 		3. Scheme	("http")
		 * 		4. Authority (host name)
		 * 		5. Username/Password (if any)
		 * 		6. Port		(server port if any)
		 *		7. Path		(/homepages/mypage.html)
		 *
		 * The reason for this order is to minimize any parsing ambiguities.
		 * Fragments and queries can contain almost anything (they are parts
		 * that can contain custom data with their own syntax).  Parsing
		 * them out first removes a large chance of parsing errors.  This
		 * method expects well formed URI's, but performing the parse in
		 * this order makes us a little more tolerant of user error.
		 * 
		 * REGEXP
		 * Why doesn't this use regular expressions to parse the URI?  We
		 * have found that in a real world scenario, URI's are not always
		 * well formed.  Sometimes characters that should have been escaped
		 * are not, and those situations would break a regexp pattern.  This
		 * function attempts to be smart about what it is parsing based on
		 * location of characters relative to each other.  This function has
		 * been proven through real-world use to parse the vast majority
		 * of URI's correctly.
		 *
		 * NOTE
		 * It is assumed that the string in URI form is escaped.  This function
		 * does not escape anything.  If you constructed the URI string by
		 * hand, and used this to parse in the URI and still need it escaped,
		 * call forceEscape() on your URI object.
		 *
		 * Parsing Assumptions
		 * This routine assumes that the URI being passed is well formed.
		 * Passing things like local paths, malformed URI's, and the such
		 * will result in parsing errors.  This function can handle
		 * 	 - absolute hierarchical (e.g. "http://something.com/index.html),
		 *   - relative hierarchical (e.g. "../images/flower.gif"), or
		 *   - non-hierarchical URIs (e.g. "mailto:jsmith@fungoo.com").
		 * 
		 * Anything else will probably result in a parsing error, or a bogus
		 * URI object.
		 * 
		 * Note that non-hierarchical URIs *MUST* have a scheme, otherwise
		 * they will be mistaken for relative URI's.
		 * 
		 * If you are not sure what is being passed to you (like manually
		 * entered text from UI), you can construct a blank URI object and
		 * call unknownToURI() passing in the unknown string.
		 * 
		 * @return	true if successful, false if there was some kind of
		 * parsing error
		 */
		protected function parseURI(uri:String) : Boolean
		{
			var baseURI:String = uri;
			var index:int, index2:int;
		
			// Make sure this object is clean before we start.  If it was used
			// before and we are now parsing a new URI, we don't want any stale
			// info lying around.
			initialize();
		
			// Remove any fragments (anchors) from the URI
			index = baseURI.indexOf("#");
			if (index != -1)
			{
				// Store the fragment piece if any
				if (baseURI.length > (index + 1)) // +1 is to skip the '#'
					_fragment = baseURI.substr(index + 1, baseURI.length - (index + 1)); 
		
				// Trim off the fragment
				baseURI = baseURI.substr(0, index);
			}
		
			// We need to strip off any CGI parameters (eg '?param=bob')
			index = baseURI.indexOf("?");
			if (index != -1)
			{
				if (baseURI.length > (index + 1))
					_query = baseURI.substr(index + 1, baseURI.length - (index + 1)); // +1 is to skip the '?'
		
				// Trim off the query
				baseURI = baseURI.substr(0, index);
			}
		
			// Now try to find the scheme part
			index = baseURI.search(':');
			index2 = baseURI.search('/');
		
			var containsColon:Boolean = (index != -1);
			var containsSlash:Boolean = (index2 != -1);
		
			// This value is indeterminate if "containsColon" is false.
			// (if there is no colon, does the slash come before or
			// after said non-existing colon?)
			var colonBeforeSlash:Boolean = (!containsSlash || index < index2);
		
			// If it has a colon and it's before the first slash, we will treat
			// it as a scheme.  If a slash is before a colon, there must be a
			// stray colon in a path or something.  In which case, the colon is
			// not the separator for the scheme.  Technically, we could consider
			// this an error, but since this is not an ambiguous state (we know
			// 100% that this has no scheme), we will keep going.
			if (containsColon && colonBeforeSlash)
			{
				// We found a scheme
				_scheme = baseURI.substr(0, index);
				
				// Normalize the scheme
				_scheme = _scheme.toLowerCase();
		
				baseURI = baseURI.substr(index + 1);
		
				if (baseURI.substr(0, 2) == "//")
				{
					// This is a hierarchical URI
					_nonHierarchical = "";
		
					// Trim off the "//"
					baseURI = baseURI.substr(2, baseURI.length - 2);
				}
				else
				{
					// This is a non-hierarchical URI like "mailto:bob@mail.com"
					_nonHierarchical = baseURI;
		
					if ((_valid = validateURI()) == false)
						initialize();  // Bad URI.  Clear it.
		
					// No more parsing to do for this case
					return isValid();
				}
			}
			else
			{
				// No scheme.  We will consider this a relative URI
				_scheme = "";
				_relative = true;
				_nonHierarchical = "";
			}
		
			// Ok, what we have left is everything after the <scheme>://
		
			// Now that we have stripped off any query and fragment parts, we
			// need to split the authority from the path
		
			if (isRelative())
			{
				// Don't bother looking for the authority.  It's a relative URI
				_authority = "";
				_port = "";
				_path = baseURI;
			}
			else
			{
				// Check for malformed UNC style file://///server/type/path/
				// By the time we get here, we have already trimmed the "file://"
				// so baseURI will be ///server/type/path.  If baseURI only
				// has one slash, we leave it alone because that is valid (that
				// is the case of "file:///path/to/file.txt" where there is no
				// server - implicit "localhost").
				if (baseURI.substr(0, 2) == "//")
				{
					// Trim all leading slashes
					while(baseURI.charAt(0) == "/")
						baseURI = baseURI.substr(1, baseURI.length - 1);
				}
		
				index = baseURI.search('/');
				if (index == -1)
				{
					// No path.  We must have passed something like "http://something.com"
					_authority = baseURI;
					_path = "";
				}
				else
				{
					_authority = baseURI.substr(0, index);
					_path = baseURI.substr(index, baseURI.length - index);
				}
		
				// Check to see if the URI has any username or password information.
				// For example:  ftp://username:password@server.com
				index = _authority.search('@');
				if (index != -1)
				{
					// We have a username and possibly a password
					_username = _authority.substr(0, index);
		
					// Remove the username/password from the authority
					_authority = _authority.substr(index + 1);  // Skip the '@'
		
					// Now check to see if the username also has a password
					index = _username.search(':');
					if (index != -1)
					{
						_password = _username.substring(index + 1, _username.length);
						_username = _username.substr(0, index);
					}
					else
						_password = "";
				}
				else
				{
					_username = "";
					_password = "";
				}
		
				// Lastly, check to see if the authorty has a port number.
				// This is parsed after the username/password to avoid conflicting
				// with the ':' in the 'username:password' if one exists.
				index = _authority.search(':');
				if (index != -1)
				{
					_port = _authority.substring(index + 1, _authority.length);  // skip the ':'
					_authority = _authority.substr(0, index);
				}
				else
				{
					_port = "";
				}
				
				// Lastly, normalize the authority.  Domain names
				// are case insensitive.
				_authority = _authority.toLowerCase();
			}
		
			if ((_valid = validateURI()) == false)
				initialize();  // Bad URI.  Clear it
		
			return isValid();
		}
		
		
		/********************************************************************
		 * Copy function.
		 */
		public function copyURI(uri:URI) : void
		{
			this._scheme = uri._scheme;
			this._authority = uri._authority;
			this._username = uri._username;
			this._password = uri._password;
			this._port = uri._port;
			this._path = uri._path;
			this._query = uri._query;
			this._fragment = uri._fragment;
			this._nonHierarchical = uri._nonHierarchical;
		
			this._valid = uri._valid;
			this._relative = uri._relative;
		}
		
		
		/**
		 * @private
		 * Checks if the given string only contains a-z or A-Z.
		 */
		protected function verifyAlpha(str:String) : Boolean
		{
			var pattern:RegExp = /[^a-z]/;
			var index:int;
			
			str = str.toLowerCase();
			index = str.search(pattern);
			
			if (index == -1)
				return true;
			else
				return false;
		}
		
		/**
		 * Is this a valid URI?
		 * 
		 * @return true if this object represents a valid URI, false
		 * otherwise.
		 */
		public function isValid() : Boolean
		{ 
			return this._valid;
		}
		
		
		/**
		 * Is this URI an absolute URI?  An absolute URI is a complete, fully
		 * qualified reference to a resource.  e.g. http://site.com/index.htm
		 * Non-hierarchical URI's are always absolute.
		 */
		public function isAbsolute() : Boolean
		{ 
			return !this._relative;
		}
		
		
		/**
		 * Is this URI a relative URI?  Relative URI's do not have a scheme
		 * and only contain a relative path with optional anchor and query
		 * parts.  e.g. "../reports/index.htm".  Non-hierarchical URI's
		 * will never be relative.
		 */
		public function isRelative() : Boolean
		{ 
			return this._relative;
		}
		
		
		/**
		 * Does this URI point to a resource that is a directory/folder?
		 * The URI specification dictates that any path that ends in a slash
		 * is a directory.  This is needed to be able to perform correct path
		 * logic when combining relative URI's with absolute URI's to
		 * obtain the correct absolute URI to a resource.
		 * 
		 * @see URI.chdir
		 * 
		 * @return true if this URI represents a directory resource, false
		 * if this URI represents a file resource.
		 */
		public function isDirectory() : Boolean
		{
			if (_path.length == 0)
				return false;
		
			return (_path.charAt(path.length - 1) == '/');
		}
		
		
		/**
		 * Is this URI a hierarchical URI? URI's can be  
		 */
		public function isHierarchical() : Boolean
		{ 
			return hierState;
		}
				
		
		/**
		 * The scheme of the URI.
		 */
		public function get scheme() : String
		{ 
			return URI.unescapeChars(_scheme);
		}
		public function set scheme(schemeStr:String) : void
		{
			// Normalize the scheme
			var normalized:String = schemeStr.toLowerCase();
			_scheme = URI.fastEscapeChars(normalized, URI.URIschemeExcludedBitmap);
		}
		
		
		/**
		 * The authority (host) of the URI.  Only valid for
		 * hierarchical URI's.  If the URI is relative, this will
		 * be an empty string. When setting this value, the string
		 * given is assumed to be unescaped.  When retrieving this
		 * value, the resulting string is unescaped.
		 */
		public function get authority() : String
		{ 
			return URI.unescapeChars(_authority);
		}
		public function set authority(authorityStr:String) : void
		{
			// Normalize the authority
			authorityStr = authorityStr.toLowerCase();
			
			_authority = URI.fastEscapeChars(authorityStr,
				URI.URIauthorityExcludedBitmap);
			
			// Only hierarchical URI's can have an authority, make
			// sure this URI is of the proper format.
			this.hierState = true;
		}
		
		
		/**
		 * The username of the URI.  Only valid for hierarchical
		 * URI's.  If the URI is relative, this will be an empty
		 * string.
		 * 
		 * <p>The URI specification allows for authentication
		 * credentials to be embedded in the URI as such:</p>
		 * 
		 * <p>http://user:passwd&#64;host/path/to/file.htm</p>
		 * 
		 * <p>When setting this value, the string
		 * given is assumed to be unescaped.  When retrieving this
		 * value, the resulting string is unescaped.</p>
		 */
		public function get username() : String
		{
			return URI.unescapeChars(_username);
		}
		public function set username(usernameStr:String) : void
		{
			_username = URI.fastEscapeChars(usernameStr, URI.URIuserpassExcludedBitmap);
			
			// Only hierarchical URI's can have a username.
			this.hierState = true;
		}
		
		
		/**
		 * The password of the URI.  Similar to username.
		 * @see URI.username
		 */
		public function get password() : String
		{
			return URI.unescapeChars(_password);
		}
		public function set password(passwordStr:String) : void
		{
			_password = URI.fastEscapeChars(passwordStr,
				URI.URIuserpassExcludedBitmap);
			
			// Only hierarchical URI's can have a password.
			this.hierState = true;
		}
		
		
		/**
		 * The host port number.  Only valid for hierarchical URI's.  If
		 * the URI is relative, this will be an empty string. URI's can
		 * contain the port number of the remote host:
		 * 
		 * <p>http://site.com:8080/index.htm</p>
		 */
		public function get port() : String
		{ 
			return URI.unescapeChars(_port);
		}
		public function set port(portStr:String) : void
		{
			_port = URI.escapeChars(portStr);
			
			// Only hierarchical URI's can have a port.
			this.hierState = true;
		}
		
		
		/**
		 * The path portion of the URI.  Only valid for hierarchical
		 * URI's.  When setting this value, the string
		 * given is assumed to be unescaped.  When retrieving this
		 * value, the resulting string is unescaped.
		 * 
		 * <p>The path portion can be in one of two formats. 1) an absolute
		 * path, or 2) a relative path.  An absolute path starts with a
		 * slash ('/'), a relative path does not.</p>
		 * 
		 * <p>An absolute path may look like:</p>
		 * <listing>/full/path/to/my/file.htm</listing>
		 * 
		 * <p>A relative path may look like:</p>
		 * <listing>
		 * path/to/my/file.htm
		 * ../images/logo.gif
		 * ../../reports/index.htm
		 * </listing>
		 * 
		 * <p>Paths can be absolute or relative.  Note that this not the same as
		 * an absolute or relative URI.  An absolute URI can only have absolute
		 * paths.  For example:</p>
		 * 
		 * <listing>http:/site.com/path/to/file.htm</listing>
		 * 
		 * <p>This absolute URI has an absolute path of "/path/to/file.htm".</p>
		 * 
		 * <p>Relative URI's can have either absolute paths or relative paths.
		 * All of the following relative URI's are valid:</p>
		 * 
		 * <listing>
		 * /absolute/path/to/file.htm
		 * path/to/file.htm
		 * ../path/to/file.htm
		 * </listing>
		 */
		public function get path() : String
		{ 
			return URI.unescapeChars(_path);
		}
		public function set path(pathStr:String) : void
		{	
			this._path = URI.fastEscapeChars(pathStr, URI.URIpathExcludedBitmap);
		
			if (this._scheme == UNKNOWN_SCHEME)
			{
				// We set the path.  This is a valid URI now.
				this._scheme = "";
			}
		
			// Only hierarchical URI's can have a path.
			hierState = true;
		}
		
		
		/**
		 * The query (CGI) portion of the URI.  This part is valid for
		 * both hierarchical and non-hierarchical URI's.
		 * 
		 * <p>This accessor should only be used if a custom query syntax
		 * is used.  This URI class supports the common "param=value"
		 * style query syntax via the get/setQueryValue() and
		 * get/setQueryByMap() functions.  Those functions should be used
		 * instead if the common syntax is being used.
		 * 
		 * <p>The URI RFC does not specify any particular
		 * syntax for the query part of a URI.  It is intended to allow
		 * any format that can be agreed upon by the two communicating hosts.
		 * However, most systems have standardized on the typical CGI
		 * format:</p>
		 * 
		 * <listing>http://site.com/script.php?param1=value1&param2=value2</listing>
		 * 
		 * <p>This class has specific support for this query syntax</p>
		 * 
		 * <p>This common query format is an array of name/value
		 * pairs with its own syntax that is different from the overall URI
		 * syntax.  The query has its own escaping logic.  For a query part
		 * to be properly escaped and unescaped, it must be split into its
		 * component parts.  This accessor escapes/unescapes the entire query
		 * part without regard for it's component parts.  This has the
		 * possibliity of leaving the query string in an ambiguous state in
		 * regards to its syntax.  If the contents of the query part are
		 * important, it is recommended that get/setQueryValue() or
		 * get/setQueryByMap() are used instead.</p>
		 * 
		 * If a different query syntax is being used, a subclass of URI
		 * can be created to handle that specific syntax.
		 *  
		 * @see URI.getQueryValue, URI.getQueryByMap
		 */
		public function get query() : String
		{ 
			return URI.unescapeChars(_query);
		}
		public function set query(queryStr:String) : void
		{
			_query = URI.fastEscapeChars(queryStr, URI.URIqueryExcludedBitmap);
			
			// both hierarchical and non-hierarchical URI's can
			// have a query.  Do not set the hierState.
		}
		
		/**
		 * Accessor to the raw query data.  If you are using a custom query
		 * syntax, this accessor can be used to get and set the query part
		 * directly with no escaping/unescaping.  This should ONLY be used
		 * if your application logic is handling custom query logic and
		 * handling the proper escaping of the query part.
		 */
		public function get queryRaw() : String
		{
			return _query;
		}
		public function set queryRaw(queryStr:String) : void
		{
			_query = queryStr;
		}


		/**
		 * The fragment (anchor) portion of the URI.  This is valid for
		 * both hierarchical and non-hierarchical URI's.
		 */
		public function get fragment() : String
		{ 
			return URI.unescapeChars(_fragment);
		}
		public function set fragment(fragmentStr:String) : void
		{
			_fragment = URI.fastEscapeChars(fragmentStr, URIfragmentExcludedBitmap);

			// both hierarchical and non-hierarchical URI's can
			// have a fragment.  Do not set the hierState.
		}
		
		
		/**
		 * The non-hierarchical part of the URI.  For example, if
		 * this URI object represents "mailto:somebody@company.com",
		 * this will contain "somebody@company.com".  This is valid only
		 * for non-hierarchical URI's.  
		 */
		public function get nonHierarchical() : String
		{ 
			return URI.unescapeChars(_nonHierarchical);
		}
		public function set nonHierarchical(nonHier:String) : void
		{
			_nonHierarchical = URI.fastEscapeChars(nonHier, URInonHierexcludedBitmap);
			
			// This is a non-hierarchical URI.
			this.hierState = false;
		}
		
		
		/**
		 * Quick shorthand accessor to set the parts of this URI.
		 * The given parts are assumed to be in unescaped form.  If
		 * the URI is non-hierarchical (e.g. mailto:) you will need
		 * to call SetScheme() and SetNonHierarchical().
		 */
		public function setParts(schemeStr:String, authorityStr:String,
				portStr:String, pathStr:String, queryStr:String,
				fragmentStr:String) : void
		{
			this.scheme = schemeStr;
			this.authority = authorityStr;
			this.port = portStr;
			this.path = pathStr;
			this.query = queryStr;
			this.fragment = fragmentStr;

			hierState = true;
		}
		
		
		/**
		 * URI escapes the given character string.  This is similar in function
		 * to the global encodeURIComponent() function in ActionScript, but is
		 * slightly different in regards to which characters get escaped.  This
		 * escapes the characters specified in the URIbaselineExluded set (see class
		 * static members).  This is needed for this class to work properly.
		 * 
		 * <p>If a different set of characters need to be used for the escaping,
		 * you may use fastEscapeChars() and specify a custom URIEncodingBitmap
		 * that contains the characters your application needs escaped.</p>
		 * 
		 * <p>Never pass a full URI to this function.  A URI can only be properly
		 * escaped/unescaped when split into its component parts (see RFC 3986
		 * section 2.4).  This is due to the fact that the URI component separators
		 * could be characters that would normally need to be escaped.</p>
		 * 
		 * @param unescaped character string to be escaped.
		 * 
		 * @return	escaped character string
		 * 
		 * @see encodeURIComponent
		 * @see fastEscapeChars
		 */
		static public function escapeChars(unescaped:String) : String
		{
			// This uses the excluded set by default.
			return fastEscapeChars(unescaped, URI.URIbaselineExcludedBitmap);
		}
		

		/**
		 * Unescape any URI escaped characters in the given character
		 * string.
		 * 
		 * <p>Never pass a full URI to this function.  A URI can only be properly
		 * escaped/unescaped when split into its component parts (see RFC 3986
		 * section 2.4).  This is due to the fact that the URI component separators
		 * could be characters that would normally need to be escaped.</p>
		 * 
		 * @param escaped the escaped string to be unescaped.
		 * 
		 * @return	unescaped string.
		 */
		static public function unescapeChars(escaped:String /*, onlyHighASCII:Boolean = false*/) : String
		{
			// We can just use the default AS function.  It seems to
			// decode everything correctly
			var unescaped:String;
			unescaped = decodeURIComponent(escaped);
			return unescaped;
		}
		
		/**
		 * Performance focused function that escapes the given character
		 * string using the given URIEncodingBitmap as the rule for what
		 * characters need to be escaped.  This function is used by this
		 * class and can be used externally to this class to perform
		 * escaping on custom character sets.
		 * 
		 * <p>Never pass a full URI to this function.  A URI can only be properly
		 * escaped/unescaped when split into its component parts (see RFC 3986
		 * section 2.4).  This is due to the fact that the URI component separators
		 * could be characters that would normally need to be escaped.</p>
		 * 
		 * @param unescaped		the unescaped string to be escaped
		 * @param bitmap		the set of characters that need to be escaped
		 * 
		 * @return	the escaped string.
		 */
		static public function fastEscapeChars(unescaped:String, bitmap:URIEncodingBitmap) : String
		{
			var escaped:String = "";
			var c:String;
			var x:int, i:int;
			
			for (i = 0; i < unescaped.length; i++)
			{
				c = unescaped.charAt(i);
				
				x = bitmap.ShouldEscape(c);
				if (x)
				{
					c = x.toString(16);
					if (c.length == 1)
						c = "0" + c;
						
					c = "%" + c;
					c = c.toUpperCase();
				}
				
				escaped += c;
			}
			
			return escaped;
		}

		
		/**
		 * Is this URI of a particular scheme type?  For example,
		 * passing "http" to a URI object that represents the URI
		 * "http://site.com/" would return true.
		 * 
		 * @param scheme	scheme to check for
		 * 
		 * @return true if this URI object is of the given type, false
		 * otherwise.
		 */
		public function isOfType(scheme:String) : Boolean
		{
			// Schemes are never case sensitive.  Ignore case.
			scheme = scheme.toLowerCase();
			return (this._scheme == scheme);
		}


		/**
		 * Get the value for the specified named in the query part.  This
		 * assumes the query part of the URI is in the common
		 * "name1=value1&name2=value2" syntax.  Do not call this function
		 * if you are using a custom query syntax.
		 * 
		 * @param name	name of the query value to get.
		 * 
		 * @return the value of the query name, empty string if the
		 * query name does not exist.
		 */
		public function getQueryValue(name:String) : String
		{
			var map:Object;
			var item:String;
			var value:String;
		
			map = getQueryByMap();
		
			for (item in map)
			{
				if (item == name)
				{
					value = map[item];
					return value;
				}
			}
		
			// Didn't find the specified key
			return new String("");
		}
		

		/**
		 * Set the given value on the given query name.  If the given name
		 * does not exist, it will automatically add this name/value pair
		 * to the query.  If null is passed as the value, it will remove
		 * the given item from the query.
		 * 
		 * <p>This automatically escapes any characters that may conflict with
		 * the query syntax so that they are "safe" within the query.  The
		 * strings passed are assumed to be literal unescaped name and value.</p>
		 * 
		 * @param name	name of the query value to set
		 * @param value	value of the query item to set.  If null, this will
		 * force the removal of this item from the query.
		 */
		public function setQueryValue(name:String, value:String) : void
		{
			var map:Object;

			map = getQueryByMap();
		
			// If the key doesn't exist yet, this will create a new pair in
			// the map.  If it does exist, this will overwrite the previous
			// value, which is what we want.
			map[name] = value;
		
			setQueryByMap(map);
		}

		
		/**
		 * Get the query of the URI in an Object class that allows for easy
		 * access to the query data via Object accessors.  For example:
		 * 
		 * <listing>
		 * var query:Object = uri.getQueryByMap();
		 * var value:String = query["param"];    // get a value
		 * query["param2"] = "foo";   // set a new value
		 * </listing>
		 * 
		 * @return Object that contains the name/value pairs of the query.
		 * 
		 * @see #setQueryByMap
		 * @see #getQueryValue
		 * @see #setQueryValue
		 */
		public function getQueryByMap() : Object
		{
			var queryStr:String;
			var pair:String;
			var pairs:Array;
			var item:Array;
			var name:String, value:String;
			var index:int;
			var map:Object = new Object();
		
		
			// We need the raw query string, no unescaping.
			queryStr = this._query;
			
			pairs = queryStr.split('&');
			for each (pair in pairs)
			{
				if (pair.length == 0)
				  continue;
				  
				item = pair.split('=');
				
				if (item.length > 0)
					name = item[0];
				else
					continue;  // empty array
				
				if (item.length > 1)
					value = item[1];
				else
					value = "";
					
				name = queryPartUnescape(name);
				value = queryPartUnescape(value);
				
				map[name] = value;
			}
	
			return map;
		}
		

		/**
		 * Set the query part of this URI using the given object as the
		 * content source.  Any member of the object that has a value of
		 * null will not be in the resulting query.
		 * 
		 * @param map	object that contains the name/value pairs as
		 *    members of that object.
		 * 
		 * @see #getQueryByMap
		 * @see #getQueryValue
		 * @see #setQueryValue
		 */
		public function setQueryByMap(map:Object) : void
		{
			var item:String;
			var name:String, value:String;
			var queryStr:String = "";
			var tmpPair:String;
			var foo:String;
		
			for (item in map)
			{
				name = item;
				value = map[item];
		
				if (value == null)
					value = "";
				
				// Need to escape the name/value pair so that they
				// don't conflict with the query syntax (specifically
				// '=', '&', and <whitespace>).
				name = queryPartEscape(name);
				value = queryPartEscape(value);
				
				tmpPair = name;
				
				if (value.length > 0)
				{
					tmpPair += "=";
					tmpPair += value;
				}

				if (queryStr.length != 0)
					queryStr += '&';  // Add the separator
		
				queryStr += tmpPair;
			}
		
			// We don't want to escape.  We already escaped the
			// individual name/value pairs.  If we escaped the
			// query string again by assigning it to "query",
			// we would have double escaping.
			_query = queryStr;
		}
		
		
		/**
		 * Similar to Escape(), except this also escapes characters that
		 * would conflict with the name/value pair query syntax.  This is
		 * intended to be called on each individual "name" and "value"
		 * in the query making sure that nothing in the name or value
		 * strings contain characters that would conflict with the query
		 * syntax (e.g. '=' and '&').
		 * 
		 * @param unescaped		unescaped string that is to be escaped.
		 * 
		 * @return escaped string.
		 * 
		 * @see #queryUnescape
		 */
		static public function queryPartEscape(unescaped:String) : String
		{
			var escaped:String = unescaped;
			escaped = URI.fastEscapeChars(unescaped, URI.URIqueryPartExcludedBitmap);
			return escaped;
		}
		

		/**
		 * Unescape the individual name/value string pairs.
		 * 
		 * @param escaped	escaped string to be unescaped
		 * 
		 * @return unescaped string
		 * 
		 * @see #queryEscape
		 */
		static public function queryPartUnescape(escaped:String) : String
		{
			var unescaped:String = escaped;
			unescaped = unescapeChars(unescaped);
			return unescaped;
		}
		
		/**
		 * Output this URI as a string.  The resulting string is properly
		 * escaped and well formed for machine processing.
		 */
		public function toString() : String
		{
			if (this == null)
				return "";
			else
				return toStringInternal(false);
		}
		
		/**
		 * Output the URI as a string that is easily readable by a human.
		 * This outputs the URI with all escape sequences unescaped to
		 * their character representation.  This makes the URI easier for
		 * a human to read, but the URI could be completely invalid
		 * because some unescaped characters may now cause ambiguous parsing.
		 * This function should only be used if you want to display a URI to
		 * a user.  This function should never be used outside that specific
		 * case.
		 * 
		 * @return the URI in string format with all escape sequences
		 * unescaped.
		 * 
		 * @see #toString
		 */
		public function toDisplayString() : String
		{
			return toStringInternal(true);
		}
		
		
		/**
		 * @private
		 * 
		 * The guts of toString()
		 */
		protected function toStringInternal(forDisplay:Boolean) : String
		{
			var uri:String = "";
			var part:String = "";
		
			if (isHierarchical() == false)
			{
				// non-hierarchical URI
		
				uri += (forDisplay ? this.scheme : _scheme);
				uri += ":";
				uri += (forDisplay ? this.nonHierarchical : _nonHierarchical);
			}
			else
			{
				// Hierarchical URI
		
				if (isRelative() == false)
				{
					// If it is not a relative URI, then we want the scheme and
					// authority parts in the string.  If it is relative, we
					// do NOT want this stuff.
		
					if (_scheme.length != 0)
					{
						part = (forDisplay ? this.scheme : _scheme);
						uri += part + ":";
					}
		
					if (_authority.length != 0 || isOfType("file"))
					{
						uri += "//";
		
						// Add on any username/password associated with this
						// authority
						if (_username.length != 0)
						{
							part = (forDisplay ? this.username : _username);
							uri += part;
		
							if (_password.length != 0)
							{
								part = (forDisplay ? this.password : _password);
								uri += ":" + part;
							}
		
							uri += "@";
						}
		
						// add the authority
						part = (forDisplay ? this.authority : _authority);
						uri += part;
		
						// Tack on the port number, if any
						if (port.length != 0)
							uri += ":" + port;
					}
				}
		
				// Tack on the path
				part = (forDisplay ? this.path : _path);
				uri += part;
		
			} // end hierarchical part
		
			// Both non-hier and hierarchical have query and fragment parts
		
			// Add on the query and fragment parts
			if (_query.length != 0)
			{
				part = (forDisplay ? this.query : _query);
				uri += "?" + part;
			}
		
			if (fragment.length != 0)
			{
				part = (forDisplay ? this.fragment : _fragment);
				uri += "#" + part;
			}
		
			return uri;
		}
	
		/**
		 * Forcefully ensure that this URI is properly escaped.
		 * 
		 * <p>Sometimes URI's are constructed by hand using strings outside
		 * this class.  In those cases, it is unlikely the URI has been
		 * properly escaped.  This function forcefully escapes this URI
		 * by unescaping each part and then re-escaping it.  If the URI
		 * did not have any escaping, the first unescape will do nothing
		 * and then the re-escape will properly escape everything.  If
		 * the URI was already escaped, the unescape and re-escape will
		 * essentally be a no-op.  This provides a safe way to make sure
		 * a URI is in the proper escaped form.</p>
		 */
		public function forceEscape() : void
		{
			// The accessors for each of the members will unescape
			// and then re-escape as we get and assign them.
			
			// Handle the parts that are common for both hierarchical
			// and non-hierarchical URI's
			this.scheme = this.scheme;
			this.setQueryByMap(this.getQueryByMap());
			this.fragment = this.fragment;
			
			if (isHierarchical())
			{
				this.authority = this.authority;
				this.path = this.path;
				this.port = this.port;
				this.username = this.username;
				this.password = this.password;
			}
			else
			{
				this.nonHierarchical = this.nonHierarchical;
			}
		}
		
		
		/**
		 * Does this URI point to a resource of the given file type?
		 * Given a file extension (or just a file name, this will strip the
		 * extension), check to see if this URI points to a file of that
		 * type.
		 * 
		 * @param extension 	string that contains a file extension with or
		 * without a dot ("html" and ".html" are both valid), or a file
		 * name with an extension (e.g. "index.html").
		 * 
		 * @return true if this URI points to a resource with the same file
		 * file extension as the extension provided, false otherwise.
		 */
		public function isOfFileType(extension:String) : Boolean
		{
			var thisExtension:String;
			var index:int;
		
			index = extension.lastIndexOf(".");
			if (index != -1)
			{
				// Strip the extension
				extension = extension.substr(index + 1);
			}
			else
			{
				// The caller passed something without a dot in it.  We
				// will assume that it is just a plain extension (e.g. "html").
				// What they passed is exactly what we want
			}
		
			thisExtension = getExtension(true);
		
			if (thisExtension == "")
				return false;
		
			// Compare the extensions ignoring case
			if (compareStr(thisExtension, extension, false) == 0)
				return true;
			else
				return false;
		}
		
		
		/**
		 * Get the ".xyz" file extension from the filename in the URI.
		 * For example, if we have the following URI:
		 * 
		 * <listing>http://something.com/path/to/my/page.html?form=yes&name=bob#anchor</listing>
		 * 
		 * <p>This will return ".html".</p>
		 * 
		 * @param minusDot   If true, this will strip the dot from the extension.
		 * If true, the above example would have returned "html".
		 * 
		 * @return  the file extension
		 */
		public function getExtension(minusDot:Boolean = false) : String
		{
			var filename:String = getFilename();
			var extension:String;
			var index:int;
		
			if (filename == "")
				return String("");
		
			index = filename.lastIndexOf(".");
		
			// If it doesn't have an extension, or if it is a "hidden" file,
			// it doesn't have an extension.  Hidden files on unix start with
			// a dot (e.g. ".login").
			if (index == -1 || index == 0)
				return String("");
		
			extension = filename.substr(index);
		
			// If the caller does not want the dot, remove it.
			if (minusDot && extension.charAt(0) == ".")
				extension = extension.substr(1);
		
			return extension;
		}
		
		/**
		 * Quick function to retrieve the file name off the end of a URI.
		 * 
		 * <p>For example, if the URI is:</p>
		 * <listing>http://something.com/some/path/to/my/file.html</listing>
		 * <p>this function will return "file.html".</p>
		 * 
		 * @param minusExtension true if the file extension should be stripped
		 * 
		 * @return the file name.  If this URI is a directory, the return
		 * value will be empty string.
		 */
		public function getFilename(minusExtension:Boolean = false) : String
		{
			if (isDirectory())
				return String("");
		
			var pathStr:String = this.path;
			var filename:String;
			var index:int;
		
			// Find the last path separator.
			index = pathStr.lastIndexOf("/");
		
			if (index != -1)
				filename = pathStr.substr(index + 1);
			else
				filename = pathStr;
		
			if (minusExtension)
			{
				// The caller has requested that the extension be removed
				index = filename.lastIndexOf(".");
		
				if (index != -1)
					filename = filename.substr(0, index);
			}
		
			return filename;
		}
		
		
		/**
		 * @private
		 * Helper function to compare strings.
		 * 
		 * @return true if the two strings are identical, false otherwise.
		 */
		static protected function compareStr(str1:String, str2:String,
			sensitive:Boolean = true) : Boolean
		{
			if (sensitive == false)
			{
				str1 = str1.toLowerCase();
				str2 = str2.toLowerCase();
			}
			
			return (str1 == str2)
		}
		
		/**
		 * Based on the type of this URI (http, ftp, etc.) get
		 * the default port used for that protocol.  This is
		 * just intended to be a helper function for the most
		 * common cases.
		 */
		public function getDefaultPort() : String
		{
			if (_scheme == "http")
				return String("80");
			else if (_scheme == "ftp")
				return String("21");
			else if (_scheme == "file")
				return String("");
			else if (_scheme == "sftp")
				return String("22"); // ssh standard port
			else
			{
				// Don't know the port for this URI type
				return String("");
			}
		}
		
		/**
		 * @private
		 * 
		 * This resolves the given URI if the application has a
		 * resolver interface defined.  This function does not
		 * modify the passed in URI and returns a new URI.
		 */
		static protected function resolve(uri:URI) : URI
		{
			var copy:URI = new URI();
			copy.copyURI(uri);
			
			if (_resolver != null)
			{
				// A resolver class has been registered.  Call it.
				return _resolver.resolve(copy);
			}
			else
			{
				// No resolver.  Nothing to do, but we don't
				// want to reuse the one passed in.
				return copy;
			}
		}
		
		/**
		 * Accessor to set and get the resolver object used by all URI
		 * objects to dynamically resolve URI's before comparison.
		 */
		static public function set resolver(resolver:IURIResolver) : void
		{
			_resolver = resolver;
		}
		static public function get resolver() : IURIResolver
		{
			return _resolver;
		}
		
		/**
		 * Given another URI, return this URI object's relation to the one given.
		 * URI's can have 1 of 4 possible relationships.  They can be unrelated,
		 * equal, parent, or a child of the given URI.
		 * 
		 * @param uri	URI to compare this URI object to.
		 * @param caseSensitive  true if the URI comparison should be done
		 * taking case into account, false if the comparison should be
		 * performed case insensitive.
		 * 
		 * @return URI.NOT_RELATED, URI.CHILD, URI.PARENT, or URI.EQUAL
		 */
		public function getRelation(uri:URI, caseSensitive:Boolean = true) : int
		{
			// Give the app a chance to resolve these URI's before we compare them.
			var thisURI:URI = URI.resolve(this);
			var thatURI:URI = URI.resolve(uri);
			
			if (thisURI.isRelative() || thatURI.isRelative())
			{
				// You cannot compare relative URI's due to their lack of context.
				// You could have two relative URI's that look like:
				//		../../images/
				//		../../images/marketing/logo.gif
				// These may appear related, but you have no overall context
				// from which to make the comparison.  The first URI could be
				// from one site and the other URI could be from another site.
				return URI.NOT_RELATED;
			}
			else if (thisURI.isHierarchical() == false || thatURI.isHierarchical() == false)
			{
				// One or both of the URI's are non-hierarchical.
				if (((thisURI.isHierarchical() == false) && (thatURI.isHierarchical() == true)) ||
					((thisURI.isHierarchical() == true) && (thatURI.isHierarchical() == false)))
				{
					// XOR.  One is hierarchical and the other is
					// non-hierarchical.  They cannot be compared.
					return URI.NOT_RELATED;
				}
				else
				{
					// They are both non-hierarchical
					if (thisURI.scheme != thatURI.scheme)
						return URI.NOT_RELATED;
		
					if (thisURI.nonHierarchical != thatURI.nonHierarchical)
						return URI.NOT_RELATED;
						
					// The two non-hierarcical URI's are equal.
					return URI.EQUAL;
				}
			}
			
			// Ok, this URI and the one we are being compared to are both
			// absolute hierarchical URI's.
		
			if (thisURI.scheme != thatURI.scheme)
				return URI.NOT_RELATED;
		
			if (thisURI.authority != thatURI.authority)
				return URI.NOT_RELATED;
		
			var thisPort:String = thisURI.port;
			var thatPort:String = thatURI.port;
			
			// Different ports are considered completely different servers.
			if (thisPort == "")
				thisPort = thisURI.getDefaultPort();
			if (thatPort == "")
				thatPort = thatURI.getDefaultPort();
		
			// Check to see if the port is the default port.
			if (thisPort != thatPort)
				return URI.NOT_RELATED;
		
			if (compareStr(thisURI.path, thatURI.path, caseSensitive))
				return URI.EQUAL;
		
			// Special case check.  If we are here, the scheme, authority,
			// and port match, and it is not a relative path, but the
			// paths did not match.  There is a special case where we
			// could have:
			//		http://something.com/
			//		http://something.com
			// Technically, these are equal.  So lets, check for this case.
			var thisPath:String = thisURI.path;
			var thatPath:String = thatURI.path;
		
			if ( (thisPath == "/" || thatPath == "/") &&
				 (thisPath == "" || thatPath == "") )
			{
				// We hit the special case.  These two are equal.
				return URI.EQUAL;
			}
		
			// Ok, the paths do not match, but one path may be a parent/child
			// of the other.  For example, we may have:
			//		http://something.com/path/to/homepage/
			//		http://something.com/path/to/homepage/images/logo.gif
			// In this case, the first is a parent of the second (or the second
			// is a child of the first, depending on which you compare to the
			// other).  To make this comparison, we must split the path into
			// its component parts (split the string on the '/' path delimiter).
			// We then compare the 
			var thisParts:Array, thatParts:Array;
			var thisPart:String, thatPart:String;
			var i:int;
		
			thisParts = thisPath.split("/");
			thatParts = thatPath.split("/");
		
			if (thisParts.length > thatParts.length)
			{
				thatPart = thatParts[thatParts.length - 1];
				if (thatPart.length > 0)
				{
					// if the last part is not empty, the passed URI is
					// not a directory.  There is no way the passed URI
					// can be a parent.
					return URI.NOT_RELATED;
				}
				else
				{
					// Remove the empty trailing part
					thatParts.pop();
				}
				
				// This may be a child of the one passed in
				for (i = 0; i < thatParts.length; i++)
				{
					thisPart = thisParts[i];
					thatPart = thatParts[i];
						
					if (compareStr(thisPart, thatPart, caseSensitive) == false)
						return URI.NOT_RELATED;
				}
		
				return URI.CHILD;
			}
			else if (thisParts.length < thatParts.length)
			{
				thisPart = thisParts[thisParts.length - 1];
				if (thisPart.length > 0)
				{
					// if the last part is not empty, this URI is not a
					// directory.  There is no way this object can be
					// a parent.
					return URI.NOT_RELATED;
				}
				else
				{
					// Remove the empty trailing part
					thisParts.pop();
				}
				
				// This may be the parent of the one passed in
				for (i = 0; i < thisParts.length; i++)
				{
					thisPart = thisParts[i];
					thatPart = thatParts[i];
		
					if (compareStr(thisPart, thatPart, caseSensitive) == false)
						return URI.NOT_RELATED;
				}
				
				return URI.PARENT;
			}
			else
			{
				// Both URI's have the same number of path components, but
				// it failed the equivelence check above.  This means that
				// the two URI's are not related.
				return URI.NOT_RELATED;
			}
			
			// If we got here, the scheme and authority are the same,
			// but the paths pointed to two different locations that
			// were in different parts of the file system tree
			return URI.NOT_RELATED;
		}
		
		/**
		 * Given another URI, return the common parent between this one
		 * and the provided URI.
		 * 
		 * @param uri the other URI from which to find a common parent
		 * @para caseSensitive true if this operation should be done
		 * with case sensitive comparisons.
		 * 
		 * @return the parent URI if successful, null otherwise.
		 */
		public function getCommonParent(uri:URI, caseSensitive:Boolean = true) : URI
		{
			var thisURI:URI = URI.resolve(this);
			var thatURI:URI = URI.resolve(uri);
		
			if(!thisURI.isAbsolute() || !thatURI.isAbsolute() ||
				thisURI.isHierarchical() == false ||
				thatURI.isHierarchical() == false)
			{
				// Both URI's must be absolute hierarchical for this to
				// make sense.
				return null;
			}
			
			var relation:int = thisURI.getRelation(thatURI);
			if (relation == URI.NOT_RELATED)
			{
				// The given URI is not related to this one.  No
				// common parent.
				return null;
			}
		
			thisURI.chdir(".");
			thatURI.chdir(".");
			
			var strBefore:String, strAfter:String;
			do
			{
				relation = thisURI.getRelation(thatURI, caseSensitive);
				if(relation == URI.EQUAL || relation == URI.PARENT)
					break;
		
				// If strBefore and strAfter end up being the same,
				// we know we are at the root of the path because
				// chdir("..") is doing nothing.
				strBefore = thisURI.toString();
				thisURI.chdir("..");
				strAfter = thisURI.toString();
			}
			while(strBefore != strAfter);
		
			return thisURI;
		}
		
		
		/**
		 * This function is used to move around in a URI in a way similar
		 * to the 'cd' or 'chdir' commands on Unix.  These operations are
		 * completely string based, using the context of the URI to
		 * determine the position within the path.  The heuristics used
		 * to determine the action are based off Appendix C in RFC 2396.
		 * 
		 * <p>URI paths that end in '/' are considered paths that point to
		 * directories, while paths that do not end in '/' are files.  For
		 * example, if you execute chdir("d") on the following URI's:<br/>
		 *    1.  http://something.com/a/b/c/  (directory)<br/>
		 *    2.  http://something.com/a/b/c  (not directory)<br/>
		 * you will get:<br/>
		 *    1.  http://something.com/a/b/c/d<br/>
		 *    2.  http://something.com/a/b/d<br/></p>
		 * 
		 * <p>See RFC 2396, Appendix C for more info.</p>
		 * 
		 * @param reference	the URI or path to "cd" to.
		 * @param escape true if the passed reference string should be URI
		 * escaped before using it.
		 * 
		 * @return true if the chdir was successful, false otherwise.
		 */
		public function chdir(reference:String, escape:Boolean = false) : Boolean
		{
			var uriReference:URI;
			var ref:String = reference;
		
			if (escape)
				ref = URI.escapeChars(reference);
		
			if (ref == "")
			{
				// NOOP
				return true;
			}
			else if (ref.substr(0, 2) == "//")
			{
				// Special case.  This is an absolute URI but without the scheme.
				// Take the scheme from this URI and tack it on.  This is
				// intended to make working with chdir() a little more
				// tolerant.
				var f:String = this.scheme + ":" + ref;
				
				return constructURI(f);
			}
			else if (ref.charAt(0) == "?")
			{
				// A relative URI that is just a query part is essentially
				// a "./?query".  We tack on the "./" here to make the rest
				// of our logic work.
				ref = "./" + ref;
			}
		
			// Parse the reference passed in as a URI.  This way we
			// get any query and fragments parsed out as well.
			uriReference = new URI(ref);
		
			if (uriReference.isAbsolute() ||
				uriReference.isHierarchical() == false)
			{
				// If the URI given is a full URI, it replaces this one.
				copyURI(uriReference);
				return true;
			}
		
		
			var thisPath:String, thatPath:String;
			var thisParts:Array, thatParts:Array;
			var thisIsDir:Boolean = false, thatIsDir:Boolean = false;
			var thisIsAbs:Boolean = false, thatIsAbs:Boolean = false;
			var lastIsDotOperation:Boolean = false;
			var curDir:String;
			var i:int;
		
			thisPath = this.path;
			thatPath = uriReference.path;
		
			if (thisPath.length > 0)
				thisParts = thisPath.split("/");
			else
				thisParts = new Array();
				
			if (thatPath.length > 0)
				thatParts = thatPath.split("/");
			else
				thatParts = new Array();
			
			if (thisParts.length > 0 && thisParts[0] == "")
			{
				thisIsAbs = true;
				thisParts.shift(); // pop the first one off the array
			}
			if (thisParts.length > 0 && thisParts[thisParts.length - 1] == "")
			{
				thisIsDir = true;
				thisParts.pop();  // pop the last one off the array
			}
				
			if (thatParts.length > 0 && thatParts[0] == "")
			{
				thatIsAbs = true;
				thatParts.shift(); // pop the first one off the array
			}
			if (thatParts.length > 0 && thatParts[thatParts.length - 1] == "")
			{
				thatIsDir = true;
				thatParts.pop();  // pop the last one off the array
			}
				
			if (thatIsAbs)
			{
				// The reference is an absolute path (starts with a slash).
				// It replaces this path wholesale.
				this.path = uriReference.path;
		
				// And it inherits the query and fragment
				this.queryRaw = uriReference.queryRaw;
				this.fragment = uriReference.fragment;
		
				return true;
			}
			else if (thatParts.length == 0 && uriReference.query == "")
			{
				// The reference must have only been a fragment.  Fragments just
				// get appended to whatever the current path is.  We don't want
				// to overwrite any query that may already exist, so this case
				// only takes on the new fragment.
				this.fragment = uriReference.fragment;
				return true;
			}
			else if (thisIsDir == false && thisParts.length > 0)
			{
				// This path ends in a file.  It goes away no matter what.
				thisParts.pop();
			}
		
			// By default, this assumes the query and fragment of the reference
			this.queryRaw = uriReference.queryRaw;
			this.fragment = uriReference.fragment;
		
			// Append the parts of the path from the passed in reference
			// to this object's path.
			thisParts = thisParts.concat(thatParts);
					
			for(i = 0; i < thisParts.length; i++)
			{
				curDir = thisParts[i];
				lastIsDotOperation = false;
		
				if (curDir == ".")
				{
					thisParts.splice(i, 1);
					i = i - 1;  // account for removing this item
					lastIsDotOperation = true;
				}
				else if (curDir == "..")
				{
					if (i >= 1)
					{
						if (thisParts[i - 1] == "..")
						{
							// If the previous is a "..", we must have skipped
							// it due to this URI being relative.  We can't
							// collapse leading ".."s in a relative URI, so
							// do nothing.
						}
						else
						{
							thisParts.splice(i - 1, 2);
							i = i - 2;  // move back to account for the 2 we removed
						}
					}
					else
					{
						// This is the first thing in the path.
		
						if (isRelative())
						{
							// We can't collapse leading ".."s in a relative
							// path.  Do noting.
						}
						else
						{
							// This is an abnormal case.  We have dot-dotted up
							// past the base of our "file system".  This is a
							// case where we had a /path/like/this.htm and were
							// given a path to chdir to like this:
							// ../../../../../../mydir
							// Obviously, it has too many ".." and will take us
							// up beyond the top of the URI.  However, according
							// RFC 2396 Appendix C.2, we should try to handle
							// these abnormal cases appropriately.  In this case,
							// we will do what UNIX command lines do if you are
							// at the root (/) of the filesystem and execute:
							// # cd ../../../../../bin
							// Which will put you in /bin.  Essentially, the extra
							// ".."'s will just get eaten.
		
							thisParts.splice(i, 1);
							i = i - 1;  // account for the ".." we just removed
						}
					}
		
					lastIsDotOperation = true;
				}
			}
			
			var finalPath:String = "";
		
			// If the last thing in the path was a "." or "..", then this thing is a
			// directory.  If the last thing isn't a dot-op, then we don't want to 
			// blow away any information about the directory (hence the "|=" binary
			// assignment).
			thatIsDir = thatIsDir || lastIsDotOperation;
		
			// Reconstruct the path with the abs/dir info we have
			finalPath = joinPath(thisParts, thisIsAbs, thatIsDir);
		
			// Set the path (automatically escaping it)
			this.path = finalPath;
		
			return true;
		}
		
		/**
		 * @private
		 * Join an array of path parts back into a URI style path string.
		 * This is used by the various path logic functions to recombine
		 * a path.  This is different than the standard Array.join()
		 * function because we need to take into account the starting and
		 * ending path delimiters if this is an absolute path or a
		 * directory.
		 * 
		 * @param parts	the Array that contains strings of each path part.
		 * @param isAbs		true if the given path is absolute
		 * @param isDir		true if the given path is a directory
		 * 
		 * @return the combined path string.
		 */
		protected function joinPath(parts:Array, isAbs:Boolean, isDir:Boolean) : String
		{
			var pathStr:String = "";
			var i:int;
		
			for (i = 0; i < parts.length; i++)
			{
				if (pathStr.length > 0)
					pathStr += "/";
		
				pathStr += parts[i];
			}
		
			// If this path is a directory, tack on the directory delimiter,
			// but only if the path contains something.  Adding this to an
			// empty path would make it "/", which is an absolute path that
			// starts at the root.
			if (isDir && pathStr.length > 0)
				pathStr += "/";
		
			if (isAbs)
				pathStr = "/" + pathStr;
		
			return pathStr;
		}
		
		/**
		 * Given an absolute URI, make this relative URI absolute using
		 * the given URI as a base.  This URI instance must be relative
		 * and the base_uri must be absolute.
		 * 
		 * @param base_uri	URI to use as the base from which to make
		 * this relative URI into an absolute URI.
		 * 
		 * @return true if successful, false otherwise.
		 */
		public function makeAbsoluteURI(base_uri:URI) : Boolean
		{
			if (isAbsolute() || base_uri.isRelative())
			{
				// This URI needs to be relative, and the base needs to be
				// absolute otherwise we won't know what to do!
				return false;
			}
		
			// Make a copy of the base URI.  We don't want to modify
			// the passed URI.
			var base:URI = new URI();
			base.copyURI(base_uri);
		
			// ChDir on the base URI.  This will preserve any query
			// and fragment we have.
			if (base.chdir(toString()) == false)
				return false;
		
			// It worked, so copy the base into this one
			copyURI(base);
		
			return true;
		}
		
		
		/**
		 * Given a URI to use as a base from which this object should be
		 * relative to, convert this object into a relative URI.  For example,
		 * if you have:
		 * 
		 * <listing>
		 * var uri1:URI = new URI("http://something.com/path/to/some/file.html");
		 * var uri2:URI = new URI("http://something.com/path/to/another/file.html");
		 * 
		 * uri1.MakeRelativePath(uri2);</listing>
		 * 
		 * <p>uri1 will have a final value of "../some/file.html"</p>
		 * 
		 * <p>Note! This function is brute force.  If you have two URI's
		 * that are completely unrelated, this will still attempt to make
		 * the relative URI.  In that case, you will most likely get a
		 * relative path that looks something like:</p>
		 * 
		 * <p>../../../../../../some/path/to/my/file.html</p>
		 * 
		 * @param base_uri the URI from which to make this URI relative
		 * 
		 * @return true if successful, false if the base_uri and this URI
		 * are not related, of if error.
		 */
		public function makeRelativeURI(base_uri:URI, caseSensitive:Boolean = true) : Boolean
		{
			var base:URI = new URI();
			base.copyURI(base_uri);
			
			var thisParts:Array, thatParts:Array;
			var finalParts:Array = new Array();
			var thisPart:String, thatPart:String, finalPath:String;
			var pathStr:String = this.path;
			var queryStr:String = this.queryRaw;
			var fragmentStr:String = this.fragment;
			var i:int;
			var diff:Boolean = false;
			var isDir:Boolean = false;
		
			if (isRelative())
			{
				// We're already relative.
				return true;
			}
		
			if (base.isRelative())
			{
				// The base is relative.  A relative base doesn't make sense.
				return false;
			}
		
		
			if ( (isOfType(base_uri.scheme) == false) ||
				(this.authority != base_uri.authority) )
			{
				// The schemes and/or authorities are different.  We can't
				// make a relative path to something that is completely
				// unrelated.
				return false;
			}
		
			// Record the state of this URI
			isDir = isDirectory();
		
			// We are based of the directory of the given URI.  We need to
			// make sure the URI is pointing to a directory.  Changing
			// directory to "." will remove any file name if the base is
			// not a directory.
			base.chdir(".");
		
			thisParts = pathStr.split("/");
			thatParts = base.path.split("/");
			
			if (thisParts.length > 0 && thisParts[0] == "")
				thisParts.shift();
			
			if (thisParts.length > 0 && thisParts[thisParts.length - 1] == "")
			{
				isDir = true;
				thisParts.pop();
			}
			
			if (thatParts.length > 0 && thatParts[0] == "")
				thatParts.shift();
			if (thatParts.length > 0 && thatParts[thatParts.length - 1] == "")
				thatParts.pop();
		
		
			// Now that we have the paths split into an array of directories,
			// we can compare the two paths.  We start from the left of side
			// of the path and start comparing.  When we either run out of
			// directories (one path is longer than the other), or we find
			// a directory that is different, we stop.  The remaining parts
			// of each path is then used to determine the relative path.  For
			// example, lets say we have:
			//    path we want to make relative: /a/b/c/d/e.txt
			//    path to use as base for relative: /a/b/f/
			//
			// This loop will start at the left, and remove directories
			// until we get a mismatch or run off the end of one of them.
			// In this example, the result will be:
			//    c/d/e.txt
			//    f
			//
			// For every part left over in the base path, we prepend a ".."
			// to the relative to get the final path:
			//   ../c/d/e.txt
			while(thatParts.length > 0)
			{
				if (thisParts.length == 0)
				{
					// we matched all there is to match, we are done.
					// This is the case where "this" object is a parent
					// path of the given URI.  eg:
					//   this.path = /a/b/				(thisParts)
					//   base.path = /a/b/c/d/e/		(thatParts)
					break;
				}
		
				thisPart = thisParts[0];
				thatPart = thatParts[0];
		
				if (compareStr(thisPart, thatPart, caseSensitive))
				{
					thisParts.shift();
					thatParts.shift();
				}
				else
					break;
			}
		
			// If there are any path info left from the base URI, that means
			// **this** object is above the given URI in the file tree.  For
			// each part left over in the given URI, we need to move up one
			// directory to get where we are.
			var dotdot:String = "..";
			for (i = 0; i < thatParts.length; i++)
			{
				finalParts.push(dotdot);
			}
		
			// Append the parts of this URI to any dot-dot's we have
			finalParts = finalParts.concat(thisParts);
		
			// Join the parts back into a path
			finalPath = joinPath(finalParts, false /* not absolute */, isDir);
		
			if (finalPath.length == 0)
			{
				// The two URI's are exactly the same.  The proper relative
				// path is:
				finalPath = "./";
			}
		
			// Set the parts of the URI, preserving the original query and
			// fragment parts.
			setParts("", "", "", finalPath, queryStr, fragmentStr);
		
			return true;
		}
		
		/**
		 * Given a string, convert it to a URI.  The string could be a
		 * full URI that is improperly escaped, a malformed URI (e.g.
		 * missing a protocol like "www.something.com"), a relative URI,
		 * or any variation there of.
		 * 
		 * <p>The intention of this function is to take anything that a
		 * user might manually enter as a URI/URL and try to determine what
		 * they mean.  This function differs from the URI constructor in
		 * that it makes some assumptions to make it easy to import user
		 * entered URI data.</p>
		 * 
		 * <p>This function is intended to be a helper function.
		 * It is not all-knowning and will probably make mistakes
		 * when attempting to parse a string of unknown origin.  If
		 * your application is receiving input from the user, your
		 * application should already have a good idea what the user
		 * should  be entering, and your application should be
		 * pre-processing the user's input to make sure it is well formed
		 * before passing it to this function.</p>
		 * 
		 * <p>It is assumed that the string given to this function is
		 * something the user may have manually entered.  Given this,
		 * the URI string is probably unescaped or improperly escaped.
		 * This function will attempt to properly escape the URI by
		 * using forceEscape().  The result is that a toString() call
		 * on a URI that was created from unknownToURI() may not match
		 * the input string due to the difference in escaping.</p>
		 *
		 * @param unknown	a potential URI string that should be parsed
		 * and loaded into this object.
		 * @param defaultScheme	if it is determined that the passed string
		 * looks like a URI, but it is missing the scheme part, this
		 * string will be used as the missing scheme.
		 * 
		 * @return	true if the given string was successfully parsed into
		 * a valid URI object, false otherwise.
		 */
		public function unknownToURI(unknown:String, defaultScheme:String = "http") : Boolean
		{
			var temp:String;
			
			if (unknown.length == 0)
			{
				this.initialize();
				return false;
			}
			
			// Some users love the backslash key.  Fix it.
			unknown = unknown.replace(/\\/g, "/");
			
			// Check for any obviously missing scheme.
			if (unknown.length >= 2)
			{
				temp = unknown.substr(0, 2);
				if (temp == "//")
					unknown = defaultScheme + ":" + unknown;
			}
			
			if (unknown.length >= 3)
			{
				temp = unknown.substr(0, 3);
				if (temp == "://")
					unknown = defaultScheme + unknown;
			}

			// Try parsing it as a normal URI
			var uri:URI = new URI(unknown);
		
			if (uri.isHierarchical() == false)
			{
				if (uri.scheme == UNKNOWN_SCHEME)
				{
					this.initialize();
					return false;
				}
		
				// It's a non-hierarchical URI
				copyURI(uri);
				forceEscape();
				return true;
			}
			else if ((uri.scheme != UNKNOWN_SCHEME) &&
				(uri.scheme.length > 0))
			{
				if ( (uri.authority.length > 0) ||
					(uri.scheme == "file") )
				{
					// file://... URI
					copyURI(uri);
					forceEscape();  // ensure proper escaping
					return true;
				}
				else if (uri.authority.length == 0 && uri.path.length == 0)
				{
					// It's is an incomplete URI (eg "http://")
					
					setParts(uri.scheme, "", "", "", "", "");
					return false;
				}
			}
			else
			{
				// Possible relative URI.  We can only detect relative URI's
				// that start with "." or "..".  If it starts with something
				// else, the parsing is ambiguous.
				var path:String = uri.path;
		
				if (path == ".." || path == "." || 
					(path.length >= 3 && path.substr(0, 3) == "../") ||
					(path.length >= 2 && path.substr(0, 2) == "./") )
				{
					// This is a relative URI.
					copyURI(uri);
					forceEscape();
					return true;
				}
			}
		
			// Ok, it looks like we are just a normal URI missing the scheme.  Tack
			// on the scheme.
			uri = new URI(defaultScheme + "://" + unknown);
		
			// Check to see if we are good now
			if (uri.scheme.length > 0 && uri.authority.length > 0)
			{
				// It was just missing the scheme.
				copyURI(uri);
				forceEscape();  // Make sure we are properly encoded.
				return true;
			}
		
			// don't know what this is
			this.initialize();
			return false;
		}
		
	} // end URI class
} // end package