JavaScript/URI.js

/*!
 * URI.js - Mutating URLs
 *
 * Version: 1.19.5
 *
 * Author: Rodney Rehm
 * Web: http://medialize.github.io/URI.js/
 *
 * Licensed under
 *   MIT License http://www.opensource.org/licenses/mit-license
 *
 */
(function (root, factory) {
  'use strict';
  // https://github.com/umdjs/umd/blob/master/returnExports.js
  if (typeof module === 'object' && module.exports) {
    // Node
    module.exports = factory(require('./punycode'), require('./IPv6'), require('./SecondLevelDomains'));
  } else if (typeof define === 'function' && define.amd) {
    // AMD. Register as an anonymous module.
    define(['./punycode', './IPv6', './SecondLevelDomains'], factory);
  } else {
    // Browser globals (root is window)
    root.URI = factory(root.punycode, root.IPv6, root.SecondLevelDomains, root);
  }
}(this, function (punycode, IPv6, SLD, root) {
  'use strict';
  /*global location, escape, unescape */
  // FIXME: v2.0.0 renamce non-camelCase properties to uppercase
  /*jshint camelcase: false */

  // save current URI variable, if any
  var _URI = root && root.URI;

  function URI(url, base) {
    var _urlSupplied = arguments.length >= 1;
    var _baseSupplied = arguments.length >= 2;

    // Allow instantiation without the 'new' keyword
    if (!(this instanceof URI)) {
      if (_urlSupplied) {
        if (_baseSupplied) {
          return new URI(url, base);
        }

        return new URI(url);
      }

      return new URI();
    }

    if (url === undefined) {
      if (_urlSupplied) {
        throw new TypeError('undefined is not a valid argument for URI');
      }

      if (typeof location !== 'undefined') {
        url = location.href + '';
      } else {
        url = '';
      }
    }

    if (url === null) {
      if (_urlSupplied) {
        throw new TypeError('null is not a valid argument for URI');
      }
    }

    this.href(url);

    // resolve to base according to http://dvcs.w3.org/hg/url/raw-file/tip/Overview.html#constructor
    if (base !== undefined) {
      return this.absoluteTo(base);
    }

    return this;
  }

  function isInteger(value) {
    return /^[0-9]+$/.test(value);
  }

  URI.version = '1.19.5';

  var p = URI.prototype;
  var hasOwn = Object.prototype.hasOwnProperty;

  function escapeRegEx(string) {
    // https://github.com/medialize/URI.js/commit/85ac21783c11f8ccab06106dba9735a31a86924d#commitcomment-821963
    return string.replace(/([.*+?^=!:${}()|[\]\/\\])/g, '\\$1');
  }

  function getType(value) {
    // IE8 doesn't return [Object Undefined] but [Object Object] for undefined value
    if (value === undefined) {
      return 'Undefined';
    }

    return String(Object.prototype.toString.call(value)).slice(8, -1);
  }

  function isArray(obj) {
    return getType(obj) === 'Array';
  }

  function filterArrayValues(data, value) {
    var lookup = {};
    var i, length;

    if (getType(value) === 'RegExp') {
      lookup = null;
    } else if (isArray(value)) {
      for (i = 0, length = value.length; i < length; i++) {
        lookup[value[i]] = true;
      }
    } else {
      lookup[value] = true;
    }

    for (i = 0, length = data.length; i < length; i++) {
      /*jshint laxbreak: true */
      var _match = lookup && lookup[data[i]] !== undefined
        || !lookup && value.test(data[i]);
      /*jshint laxbreak: false */
      if (_match) {
        data.splice(i, 1);
        length--;
        i--;
      }
    }

    return data;
  }

  function arrayContains(list, value) {
    var i, length;

    // value may be string, number, array, regexp
    if (isArray(value)) {
      // Note: this can be optimized to O(n) (instead of current O(m * n))
      for (i = 0, length = value.length; i < length; i++) {
        if (!arrayContains(list, value[i])) {
          return false;
        }
      }

      return true;
    }

    var _type = getType(value);
    for (i = 0, length = list.length; i < length; i++) {
      if (_type === 'RegExp') {
        if (typeof list[i] === 'string' && list[i].match(value)) {
          return true;
        }
      } else if (list[i] === value) {
        return true;
      }
    }

    return false;
  }

  function arraysEqual(one, two) {
    if (!isArray(one) || !isArray(two)) {
      return false;
    }

    // arrays can't be equal if they have different amount of content
    if (one.length !== two.length) {
      return false;
    }

    one.sort();
    two.sort();

    for (var i = 0, l = one.length; i < l; i++) {
      if (one[i] !== two[i]) {
        return false;
      }
    }

    return true;
  }

  function trimSlashes(text) {
    var trim_expression = /^\/+|\/+$/g;
    return text.replace(trim_expression, '');
  }

  URI._parts = function() {
    return {
      protocol: null,
      username: null,
      password: null,
      hostname: null,
      urn: null,
      port: null,
      path: null,
      query: null,
      fragment: null,
      // state
      preventInvalidHostname: URI.preventInvalidHostname,
      duplicateQueryParameters: URI.duplicateQueryParameters,
      escapeQuerySpace: URI.escapeQuerySpace
    };
  };
  // state: throw on invalid hostname
  // see https://github.com/medialize/URI.js/pull/345
  // and https://github.com/medialize/URI.js/issues/354
  URI.preventInvalidHostname = false;
  // state: allow duplicate query parameters (a=1&a=1)
  URI.duplicateQueryParameters = false;
  // state: replaces + with %20 (space in query strings)
  URI.escapeQuerySpace = true;
  // static properties
  URI.protocol_expression = /^[a-z][a-z0-9.+-]*$/i;
  URI.idn_expression = /[^a-z0-9\._-]/i;
  URI.punycode_expression = /(xn--)/i;
  // well, 333.444.555.666 matches, but it sure ain't no IPv4 - do we care?
  URI.ip4_expression = /^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$/;
  // credits to Rich Brown
  // source: http://forums.intermapper.com/viewtopic.php?p=1096#1096
  // specification: http://www.ietf.org/rfc/rfc4291.txt
  URI.ip6_expression = /^\s*((([0-9A-Fa-f]{1,4}:){7}([0-9A-Fa-f]{1,4}|:))|(([0-9A-Fa-f]{1,4}:){6}(:[0-9A-Fa-f]{1,4}|((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3})|:))|(([0-9A-Fa-f]{1,4}:){5}(((:[0-9A-Fa-f]{1,4}){1,2})|:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3})|:))|(([0-9A-Fa-f]{1,4}:){4}(((:[0-9A-Fa-f]{1,4}){1,3})|((:[0-9A-Fa-f]{1,4})?:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){3}(((:[0-9A-Fa-f]{1,4}){1,4})|((:[0-9A-Fa-f]{1,4}){0,2}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){2}(((:[0-9A-Fa-f]{1,4}){1,5})|((:[0-9A-Fa-f]{1,4}){0,3}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(([0-9A-Fa-f]{1,4}:){1}(((:[0-9A-Fa-f]{1,4}){1,6})|((:[0-9A-Fa-f]{1,4}){0,4}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:))|(:(((:[0-9A-Fa-f]{1,4}){1,7})|((:[0-9A-Fa-f]{1,4}){0,5}:((25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)(\.(25[0-5]|2[0-4]\d|1\d\d|[1-9]?\d)){3}))|:)))(%.+)?\s*$/;
  // expression used is "gruber revised" (@gruber v2) determined to be the
  // best solution in a regex-golf we did a couple of ages ago at
  // * http://mathiasbynens.be/demo/url-regex
  // * http://rodneyrehm.de/t/url-regex.html
  URI.find_uri_expression = /\b((?:[a-z][\w-]+:(?:\/{1,3}|[a-z0-9%])|www\d{0,3}[.]|[a-z0-9.\-]+[.][a-z]{2,4}\/)(?:[^\s()<>]+|\(([^\s()<>]+|(\([^\s()<>]+\)))*\))+(?:\(([^\s()<>]+|(\([^\s()<>]+\)))*\)|[^\s`!()\[\]{};:'".,<>?«»“”‘’]))/ig;
  URI.findUri = {
    // valid "scheme://" or "www."
    start: /\b(?:([a-z][a-z0-9.+-]*:\/\/)|www\.)/gi,
    // everything up to the next whitespace
    end: /[\s\r\n]|$/,
    // trim trailing punctuation captured by end RegExp
    trim: /[`!()\[\]{};:'".,<>?«»“”„‘’]+$/,
    // balanced parens inclusion (), [], {}, <>
    parens: /(\([^\)]*\)|\[[^\]]*\]|\{[^}]*\}|<[^>]*>)/g,
  };
  // http://www.iana.org/assignments/uri-schemes.html
  // http://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers#Well-known_ports
  URI.defaultPorts = {
    http: '80',
    https: '443',
    ftp: '21',
    gopher: '70',
    ws: '80',
    wss: '443'
  };
  // list of protocols which always require a hostname
  URI.hostProtocols = [
    'http',
    'https'
  ];

  // allowed hostname characters according to RFC 3986
  // ALPHA DIGIT "-" "." "_" "~" "!" "$" "&" "'" "(" ")" "*" "+" "," ";" "=" %encoded
  // I've never seen a (non-IDN) hostname other than: ALPHA DIGIT . - _
  URI.invalid_hostname_characters = /[^a-zA-Z0-9\.\-:_]/;
  // map DOM Elements to their URI attribute
  URI.domAttributes = {
    'a': 'href',
    'blockquote': 'cite',
    'link': 'href',
    'base': 'href',
    'script': 'src',
    'form': 'action',
    'img': 'src',
    'area': 'href',
    'iframe': 'src',
    'embed': 'src',
    'source': 'src',
    'track': 'src',
    'input': 'src', // but only if type="image"
    'audio': 'src',
    'video': 'src'
  };
  URI.getDomAttribute = function(node) {
    if (!node || !node.nodeName) {
      return undefined;
    }

    var nodeName = node.nodeName.toLowerCase();
    // <input> should only expose src for type="image"
    if (nodeName === 'input' && node.type !== 'image') {
      return undefined;
    }

    return URI.domAttributes[nodeName];
  };

  function escapeForDumbFirefox36(value) {
    // https://github.com/medialize/URI.js/issues/91
    return escape(value);
  }

  // encoding / decoding according to RFC3986
  function strictEncodeURIComponent(string) {
    // see https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/encodeURIComponent
    return encodeURIComponent(string)
      .replace(/[!'()*]/g, escapeForDumbFirefox36)
      .replace(/\*/g, '%2A');
  }
  URI.encode = strictEncodeURIComponent;
  URI.decode = decodeURIComponent;
  URI.iso8859 = function() {
    URI.encode = escape;
    URI.decode = unescape;
  };
  URI.unicode = function() {
    URI.encode = strictEncodeURIComponent;
    URI.decode = decodeURIComponent;
  };
  URI.characters = {
    pathname: {
      encode: {
        // RFC3986 2.1: For consistency, URI producers and normalizers should
        // use uppercase hexadecimal digits for all percent-encodings.
        expression: /%(24|26|2B|2C|3B|3D|3A|40)/ig,
        map: {
          // -._~!'()*
          '%24': '$',
          '%26': '&',
          '%2B': '+',
          '%2C': ',',
          '%3B': ';',
          '%3D': '=',
          '%3A': ':',
          '%40': '@'
        }
      },
      decode: {
        expression: /[\/\?#]/g,
        map: {
          '/': '%2F',
          '?': '%3F',
          '#': '%23'
        }
      }
    },
    reserved: {
      encode: {
        // RFC3986 2.1: For consistency, URI producers and normalizers should
        // use uppercase hexadecimal digits for all percent-encodings.
        expression: /%(21|23|24|26|27|28|29|2A|2B|2C|2F|3A|3B|3D|3F|40|5B|5D)/ig,
        map: {
          // gen-delims
          '%3A': ':',
          '%2F': '/',
          '%3F': '?',
          '%23': '#',
          '%5B': '[',
          '%5D': ']',
          '%40': '@',
          // sub-delims
          '%21': '!',
          '%24': '$',
          '%26': '&',
          '%27': '\'',
          '%28': '(',
          '%29': ')',
          '%2A': '*',
          '%2B': '+',
          '%2C': ',',
          '%3B': ';',
          '%3D': '='
        }
      }
    },
    urnpath: {
      // The characters under `encode` are the characters called out by RFC 2141 as being acceptable
      // for usage in a URN. RFC2141 also calls out "-", ".", and "_" as acceptable characters, but
      // these aren't encoded by encodeURIComponent, so we don't have to call them out here. Also
      // note that the colon character is not featured in the encoding map; this is because URI.js
      // gives the colons in URNs semantic meaning as the delimiters of path segements, and so it
      // should not appear unencoded in a segment itself.
      // See also the note above about RFC3986 and capitalalized hex digits.
      encode: {
        expression: /%(21|24|27|28|29|2A|2B|2C|3B|3D|40)/ig,
        map: {
          '%21': '!',
          '%24': '$',
          '%27': '\'',
          '%28': '(',
          '%29': ')',
          '%2A': '*',
          '%2B': '+',
          '%2C': ',',
          '%3B': ';',
          '%3D': '=',
          '%40': '@'
        }
      },
      // These characters are the characters called out by RFC2141 as "reserved" characters that
      // should never appear in a URN, plus the colon character (see note above).
      decode: {
        expression: /[\/\?#:]/g,
        map: {
          '/': '%2F',
          '?': '%3F',
          '#': '%23',
          ':': '%3A'
        }
      }
    }
  };
  URI.encodeQuery = function(string, escapeQuerySpace) {
    var escaped = URI.encode(string + '');
    if (escapeQuerySpace === undefined) {
      escapeQuerySpace = URI.escapeQuerySpace;
    }

    return escapeQuerySpace ? escaped.replace(/%20/g, '+') : escaped;
  };
  URI.decodeQuery = function(string, escapeQuerySpace) {
    string += '';
    if (escapeQuerySpace === undefined) {
      escapeQuerySpace = URI.escapeQuerySpace;
    }

    try {
      return URI.decode(escapeQuerySpace ? string.replace(/\+/g, '%20') : string);
    } catch(e) {
      // we're not going to mess with weird encodings,
      // give up and return the undecoded original string
      // see https://github.com/medialize/URI.js/issues/87
      // see https://github.com/medialize/URI.js/issues/92
      return string;
    }
  };
  // generate encode/decode path functions
  var _parts = {'encode':'encode', 'decode':'decode'};
  var _part;
  var generateAccessor = function(_group, _part) {
    return function(string) {
      try {
        return URI[_part](string + '').replace(URI.characters[_group][_part].expression, function(c) {
          return URI.characters[_group][_part].map[c];
        });
      } catch (e) {
        // we're not going to mess with weird encodings,
        // give up and return the undecoded original string
        // see https://github.com/medialize/URI.js/issues/87
        // see https://github.com/medialize/URI.js/issues/92
        return string;
      }
    };
  };

  for (_part in _parts) {
    URI[_part + 'PathSegment'] = generateAccessor('pathname', _parts[_part]);
    URI[_part + 'UrnPathSegment'] = generateAccessor('urnpath', _parts[_part]);
  }

  var generateSegmentedPathFunction = function(_sep, _codingFuncName, _innerCodingFuncName) {
    return function(string) {
      // Why pass in names of functions, rather than the function objects themselves? The
      // definitions of some functions (but in particular, URI.decode) will occasionally change due
      // to URI.js having ISO8859 and Unicode modes. Passing in the name and getting it will ensure
      // that the functions we use here are "fresh".
      var actualCodingFunc;
      if (!_innerCodingFuncName) {
        actualCodingFunc = URI[_codingFuncName];
      } else {
        actualCodingFunc = function(string) {
          return URI[_codingFuncName](URI[_innerCodingFuncName](string));
        };
      }

      var segments = (string + '').split(_sep);

      for (var i = 0, length = segments.length; i < length; i++) {
        segments[i] = actualCodingFunc(segments[i]);
      }

      return segments.join(_sep);
    };
  };

  // This takes place outside the above loop because we don't want, e.g., encodeUrnPath functions.
  URI.decodePath = generateSegmentedPathFunction('/', 'decodePathSegment');
  URI.decodeUrnPath = generateSegmentedPathFunction(':', 'decodeUrnPathSegment');
  URI.recodePath = generateSegmentedPathFunction('/', 'encodePathSegment', 'decode');
  URI.recodeUrnPath = generateSegmentedPathFunction(':', 'encodeUrnPathSegment', 'decode');

  URI.encodeReserved = generateAccessor('reserved', 'encode');

  URI.parse = function(string, parts) {
    var pos;
    if (!parts) {
      parts = {
        preventInvalidHostname: URI.preventInvalidHostname
      };
    }
    // [protocol"://"[username[":"password]"@"]hostname[":"port]"/"?][path]["?"querystring]["#"fragment]

    // extract fragment
    pos = string.indexOf('#');
    if (pos > -1) {
      // escaping?
      parts.fragment = string.substring(pos + 1) || null;
      string = string.substring(0, pos);
    }

    // extract query
    pos = string.indexOf('?');
    if (pos > -1) {
      // escaping?
      parts.query = string.substring(pos + 1) || null;
      string = string.substring(0, pos);
    }

    // extract protocol
    if (string.substring(0, 2) === '//') {
      // relative-scheme
      parts.protocol = null;
      string = string.substring(2);
      // extract "user:pass@host:port"
      string = URI.parseAuthority(string, parts);
    } else {
      pos = string.indexOf(':');
      if (pos > -1) {
        parts.protocol = string.substring(0, pos) || null;
        if (parts.protocol && !parts.protocol.match(URI.protocol_expression)) {
          // : may be within the path
          parts.protocol = undefined;
        // BUG: NVD-CWE-noinfo Insufficient Information
        // } else if (string.substring(pos + 1, pos + 3) === '//') {
        // FIXED: 
        } else if (string.substring(pos + 1, pos + 3).replace(/\\/g, '/') === '//') {
          string = string.substring(pos + 3);

          // extract "user:pass@host:port"
          string = URI.parseAuthority(string, parts);
        } else {
          string = string.substring(pos + 1);
          parts.urn = true;
        }
      }
    }

    // what's left must be the path
    parts.path = string;

    // and we're done
    return parts;
  };
  URI.parseHost = function(string, parts) {
    if (!string) {
      string = '';
    }

    // Copy chrome, IE, opera backslash-handling behavior.
    // Back slashes before the query string get converted to forward slashes
    // See: https://github.com/joyent/node/blob/386fd24f49b0e9d1a8a076592a404168faeecc34/lib/url.js#L115-L124
    // See: https://code.google.com/p/chromium/issues/detail?id=25916
    // https://github.com/medialize/URI.js/pull/233
    string = string.replace(/\\/g, '/');

    // extract host:port
    var pos = string.indexOf('/');
    var bracketPos;
    var t;

    if (pos === -1) {
      pos = string.length;
    }

    if (string.charAt(0) === '[') {
      // IPv6 host - http://tools.ietf.org/html/draft-ietf-6man-text-addr-representation-04#section-6
      // I claim most client software breaks on IPv6 anyways. To simplify things, URI only accepts
      // IPv6+port in the format [2001:db8::1]:80 (for the time being)
      bracketPos = string.indexOf(']');
      parts.hostname = string.substring(1, bracketPos) || null;
      parts.port = string.substring(bracketPos + 2, pos) || null;
      if (parts.port === '/') {
        parts.port = null;
      }
    } else {
      var firstColon = string.indexOf(':');
      var firstSlash = string.indexOf('/');
      var nextColon = string.indexOf(':', firstColon + 1);
      if (nextColon !== -1 && (firstSlash === -1 || nextColon < firstSlash)) {
        // IPv6 host contains multiple colons - but no port
        // this notation is actually not allowed by RFC 3986, but we're a liberal parser
        parts.hostname = string.substring(0, pos) || null;
        parts.port = null;
      } else {
        t = string.substring(0, pos).split(':');
        parts.hostname = t[0] || null;
        parts.port = t[1] || null;
      }
    }

    if (parts.hostname && string.substring(pos).charAt(0) !== '/') {
      pos++;
      string = '/' + string;
    }

    if (parts.preventInvalidHostname) {
      URI.ensureValidHostname(parts.hostname, parts.protocol);
    }

    if (parts.port) {
      URI.ensureValidPort(parts.port);
    }

    return string.substring(pos) || '/';
  };
  URI.parseAuthority = function(string, parts) {
    string = URI.parseUserinfo(string, parts);
    return URI.parseHost(string, parts);
  };
  URI.parseUserinfo = function(string, parts) {
    // extract username:password
    var _string = string
    var firstBackSlash = string.indexOf('\\');
    if (firstBackSlash !== -1) {
      string = string.replace(/\\/g, '/')
    }
    var firstSlash = string.indexOf('/');
    var pos = string.lastIndexOf('@', firstSlash > -1 ? firstSlash : string.length - 1);
    var t;

    // authority@ must come before /path or \path
    if (pos > -1 && (firstSlash === -1 || pos < firstSlash)) {
      t = string.substring(0, pos).split(':');
      parts.username = t[0] ? URI.decode(t[0]) : null;
      t.shift();
      parts.password = t[0] ? URI.decode(t.join(':')) : null;
      string = _string.substring(pos + 1);
    } else {
      parts.username = null;
      parts.password = null;
    }

    return string;
  };
  URI.parseQuery = function(string, escapeQuerySpace) {
    if (!string) {
      return {};
    }

    // throw out the funky business - "?"[name"="value"&"]+
    string = string.replace(/&+/g, '&').replace(/^\?*&*|&+$/g, '');

    if (!string) {
      return {};
    }

    var items = {};
    var splits = string.split('&');
    var length = splits.length;
    var v, name, value;

    for (var i = 0; i < length; i++) {
      v = splits[i].split('=');
      name = URI.decodeQuery(v.shift(), escapeQuerySpace);
      // no "=" is null according to http://dvcs.w3.org/hg/url/raw-file/tip/Overview.html#collect-url-parameters
      value = v.length ? URI.decodeQuery(v.join('='), escapeQuerySpace) : null;

      if (hasOwn.call(items, name)) {
        if (typeof items[name] === 'string' || items[name] === null) {
          items[name] = [items[name]];
        }

        items[name].push(value);
      } else {
        items[name] = value;
      }
    }

    return items;
  };

  URI.build = function(parts) {
    var t = '';
    var requireAbsolutePath = false

    if (parts.protocol) {
      t += parts.protocol + ':';
    }

    if (!parts.urn && (t || parts.hostname)) {
      t += '//';
      requireAbsolutePath = true
    }

    t += (URI.buildAuthority(parts) || '');

    if (typeof parts.path === 'string') {
      if (parts.path.charAt(0) !== '/' && requireAbsolutePath) {
        t += '/';
      }

      t += parts.path;
    }

    if (typeof parts.query === 'string' && parts.query) {
      t += '?' + parts.query;
    }

    if (typeof parts.fragment === 'string' && parts.fragment) {
      t += '#' + parts.fragment;
    }
    return t;
  };
  URI.buildHost = function(parts) {
    var t = '';

    if (!parts.hostname) {
      return '';
    } else if (URI.ip6_expression.test(parts.hostname)) {
      t += '[' + parts.hostname + ']';
    } else {
      t += parts.hostname;
    }

    if (parts.port) {
      t += ':' + parts.port;
    }

    return t;
  };
  URI.buildAuthority = function(parts) {
    return URI.buildUserinfo(parts) + URI.buildHost(parts);
  };
  URI.buildUserinfo = function(parts) {
    var t = '';

    if (parts.username) {
      t += URI.encode(parts.username);
    }

    if (parts.password) {
      t += ':' + URI.encode(parts.password);
    }

    if (t) {
      t += '@';
    }

    return t;
  };
  URI.buildQuery = function(data, duplicateQueryParameters, escapeQuerySpace) {
    // according to http://tools.ietf.org/html/rfc3986 or http://labs.apache.org/webarch/uri/rfc/rfc3986.html
    // being »-._~!$&'()*+,;=:@/?« %HEX and alnum are allowed
    // the RFC explicitly states ?/foo being a valid use case, no mention of parameter syntax!
    // URI.js treats the query string as being application/x-www-form-urlencoded
    // see http://www.w3.org/TR/REC-html40/interact/forms.html#form-content-type

    var t = '';
    var unique, key, i, length;
    for (key in data) {
      if (hasOwn.call(data, key)) {
        if (isArray(data[key])) {
          unique = {};
          for (i = 0, length = data[key].length; i < length; i++) {
            if (data[key][i] !== undefined && unique[data[key][i] + ''] === undefined) {
              t += '&' + URI.buildQueryParameter(key, data[key][i], escapeQuerySpace);
              if (duplicateQueryParameters !== true) {
                unique[data[key][i] + ''] = true;
              }
            }
          }
        } else if (data[key] !== undefined) {
          t += '&' + URI.buildQueryParameter(key, data[key], escapeQuerySpace);
        }
      }
    }

    return t.substring(1);
  };
  URI.buildQueryParameter = function(name, value, escapeQuerySpace) {
    // http://www.w3.org/TR/REC-html40/interact/forms.html#form-content-type -- application/x-www-form-urlencoded
    // don't append "=" for null values, according to http://dvcs.w3.org/hg/url/raw-file/tip/Overview.html#url-parameter-serialization
    return URI.encodeQuery(name, escapeQuerySpace) + (value !== null ? '=' + URI.encodeQuery(value, escapeQuerySpace) : '');
  };

  URI.addQuery = function(data, name, value) {
    if (typeof name === 'object') {
      for (var key in name) {
        if (hasOwn.call(name, key)) {
          URI.addQuery(data, key, name[key]);
        }
      }
    } else if (typeof name === 'string') {
      if (data[name] === undefined) {
        data[name] = value;
        return;
      } else if (typeof data[name] === 'string') {
        data[name] = [data[name]];
      }

      if (!isArray(value)) {
        value = [value];
      }

      data[name] = (data[name] || []).concat(value);
    } else {
      throw new TypeError('URI.addQuery() accepts an object, string as the name parameter');
    }
  };

  URI.setQuery = function(data, name, value) {
    if (typeof name === 'object') {
      for (var key in name) {
        if (hasOwn.call(name, key)) {
          URI.setQuery(data, key, name[key]);
        }
      }
    } else if (typeof name === 'string') {
      data[name] = value === undefined ? null : value;
    } else {
      throw new TypeError('URI.setQuery() accepts an object, string as the name parameter');
    }
  };

  URI.removeQuery = function(data, name, value) {
    var i, length, key;

    if (isArray(name)) {
      for (i = 0, length = name.length; i < length; i++) {
        data[name[i]] = undefined;
      }
    } else if (getType(name) === 'RegExp') {
      for (key in data) {
        if (name.test(key)) {
          data[key] = undefined;
        }
      }
    } else if (typeof name === 'object') {
      for (key in name) {
        if (hasOwn.call(name, key)) {
          URI.removeQuery(data, key, name[key]);
        }
      }
    } else if (typeof name === 'string') {
      if (value !== undefined) {
        if (getType(value) === 'RegExp') {
          if (!isArray(data[name]) && value.test(data[name])) {
            data[name] = undefined;
          } else {
            data[name] = filterArrayValues(data[name], value);
          }
        } else if (data[name] === String(value) && (!isArray(value) || value.length === 1)) {
          data[name] = undefined;
        } else if (isArray(data[name])) {
          data[name] = filterArrayValues(data[name], value);
        }
      } else {
        data[name] = undefined;
      }
    } else {
      throw new TypeError('URI.removeQuery() accepts an object, string, RegExp as the first parameter');
    }
  };
  URI.hasQuery = function(data, name, value, withinArray) {
    switch (getType(name)) {
      case 'String':
        // Nothing to do here
        break;

      case 'RegExp':
        for (var key in data) {
          if (hasOwn.call(data, key)) {
            if (name.test(key) && (value === undefined || URI.hasQuery(data, key, value))) {
              return true;
            }
          }
        }

        return false;

      case 'Object':
        for (var _key in name) {
          if (hasOwn.call(name, _key)) {
            if (!URI.hasQuery(data, _key, name[_key])) {
              return false;
            }
          }
        }

        return true;

      default:
        throw new TypeError('URI.hasQuery() accepts a string, regular expression or object as the name parameter');
    }

    switch (getType(value)) {
      case 'Undefined':
        // true if exists (but may be empty)
        return name in data; // data[name] !== undefined;

      case 'Boolean':
        // true if exists and non-empty
        var _booly = Boolean(isArray(data[name]) ? data[name].length : data[name]);
        return value === _booly;

      case 'Function':
        // allow complex comparison
        return !!value(data[name], name, data);

      case 'Array':
        if (!isArray(data[name])) {
          return false;
        }

        var op = withinArray ? arrayContains : arraysEqual;
        return op(data[name], value);

      case 'RegExp':
        if (!isArray(data[name])) {
          return Boolean(data[name] && data[name].match(value));
        }

        if (!withinArray) {
          return false;
        }

        return arrayContains(data[name], value);

      case 'Number':
        value = String(value);
        /* falls through */
      case 'String':
        if (!isArray(data[name])) {
          return data[name] === value;
        }

        if (!withinArray) {
          return false;
        }

        return arrayContains(data[name], value);

      default:
        throw new TypeError('URI.hasQuery() accepts undefined, boolean, string, number, RegExp, Function as the value parameter');
    }
  };


  URI.joinPaths = function() {
    var input = [];
    var segments = [];
    var nonEmptySegments = 0;

    for (var i = 0; i < arguments.length; i++) {
      var url = new URI(arguments[i]);
      input.push(url);
      var _segments = url.segment();
      for (var s = 0; s < _segments.length; s++) {
        if (typeof _segments[s] === 'string') {
          segments.push(_segments[s]);
        }

        if (_segments[s]) {
          nonEmptySegments++;
        }
      }
    }

    if (!segments.length || !nonEmptySegments) {
      return new URI('');
    }

    var uri = new URI('').segment(segments);

    if (input[0].path() === '' || input[0].path().slice(0, 1) === '/') {
      uri.path('/' + uri.path());
    }

    return uri.normalize();
  };

  URI.commonPath = function(one, two) {
    var length = Math.min(one.length, two.length);
    var pos;

    // find first non-matching character
    for (pos = 0; pos < length; pos++) {
      if (one.charAt(pos) !== two.charAt(pos)) {
        pos--;
        break;
      }
    }

    if (pos < 1) {
      return one.charAt(0) === two.charAt(0) && one.charAt(0) === '/' ? '/' : '';
    }

    // revert to last /
    if (one.charAt(pos) !== '/' || two.charAt(pos) !== '/') {
      pos = one.substring(0, pos).lastIndexOf('/');
    }

    return one.substring(0, pos + 1);
  };

  URI.withinString = function(string, callback, options) {
    options || (options = {});
    var _start = options.start || URI.findUri.start;
    var _end = options.end || URI.findUri.end;
    var _trim = options.trim || URI.findUri.trim;
    var _parens = options.parens || URI.findUri.parens;
    var _attributeOpen = /[a-z0-9-]=["']?$/i;

    _start.lastIndex = 0;
    while (true) {
      var match = _start.exec(string);
      if (!match) {
        break;
      }

      var start = match.index;
      if (options.ignoreHtml) {
        // attribut(e=["']?$)
        var attributeOpen = string.slice(Math.max(start - 3, 0), start);
        if (attributeOpen && _attributeOpen.test(attributeOpen)) {
          continue;
        }
      }

      var end = start + string.slice(start).search(_end);
      var slice = string.slice(start, end);
      // make sure we include well balanced parens
      var parensEnd = -1;
      while (true) {
        var parensMatch = _parens.exec(slice);
        if (!parensMatch) {
          break;
        }

        var parensMatchEnd = parensMatch.index + parensMatch[0].length;
        parensEnd = Math.max(parensEnd, parensMatchEnd);
      }

      if (parensEnd > -1) {
        slice = slice.slice(0, parensEnd) + slice.slice(parensEnd).replace(_trim, '');
      } else {
        slice = slice.replace(_trim, '');
      }

      if (slice.length <= match[0].length) {
        // the extract only contains the starting marker of a URI,
        // e.g. "www" or "http://"
        continue;
      }

      if (options.ignore && options.ignore.test(slice)) {
        continue;
      }

      end = start + slice.length;
      var result = callback(slice, start, end, string);
      if (result === undefined) {
        _start.lastIndex = end;
        continue;
      }

      result = String(result);
      string = string.slice(0, start) + result + string.slice(end);
      _start.lastIndex = start + result.length;
    }

    _start.lastIndex = 0;
    return string;
  };

  URI.ensureValidHostname = function(v, protocol) {
    // Theoretically URIs allow percent-encoding in Hostnames (according to RFC 3986)
    // they are not part of DNS and therefore ignored by URI.js

    var hasHostname = !!v; // not null and not an empty string
    var hasProtocol = !!protocol;
    var rejectEmptyHostname = false;

    if (hasProtocol) {
      rejectEmptyHostname = arrayContains(URI.hostProtocols, protocol);
    }

    if (rejectEmptyHostname && !hasHostname) {
      throw new TypeError('Hostname cannot be empty, if protocol is ' + protocol);
    } else if (v && v.match(URI.invalid_hostname_characters)) {
      // test punycode
      if (!punycode) {
        throw new TypeError('Hostname "' + v + '" contains characters other than [A-Z0-9.-:_] and Punycode.js is not available');
      }
      if (punycode.toASCII(v).match(URI.invalid_hostname_characters)) {
        throw new TypeError('Hostname "' + v + '" contains characters other than [A-Z0-9.-:_]');
      }
    }
  };

  URI.ensureValidPort = function (v) {
    if (!v) {
      return;
    }

    var port = Number(v);
    if (isInteger(port) && (port > 0) && (port < 65536)) {
      return;
    }

    throw new TypeError('Port "' + v + '" is not a valid port');
  };

  // noConflict
  URI.noConflict = function(removeAll) {
    if (removeAll) {
      var unconflicted = {
        URI: this.noConflict()
      };

      if (root.URITemplate && typeof root.URITemplate.noConflict === 'function') {
        unconflicted.URITemplate = root.URITemplate.noConflict();
      }

      if (root.IPv6 && typeof root.IPv6.noConflict === 'function') {
        unconflicted.IPv6 = root.IPv6.noConflict();
      }

      if (root.SecondLevelDomains && typeof root.SecondLevelDomains.noConflict === 'function') {
        unconflicted.SecondLevelDomains = root.SecondLevelDomains.noConflict();
      }

      return unconflicted;
    } else if (root.URI === this) {
      root.URI = _URI;
    }

    return this;
  };

  p.build = function(deferBuild) {
    if (deferBuild === true) {
      this._deferred_build = true;
    } else if (deferBuild === undefined || this._deferred_build) {
      this._string = URI.build(this._parts);
      this._deferred_build = false;
    }

    return this;
  };

  p.clone = function() {
    return new URI(this);
  };

  p.valueOf = p.toString = function() {
    return this.build(false)._string;
  };


  function generateSimpleAccessor(_part){
    return function(v, build) {
      if (v === undefined) {
        return this._parts[_part] || '';
      } else {
        this._parts[_part] = v || null;
        this.build(!build);
        return this;
      }
    };
  }

  function generatePrefixAccessor(_part, _key){
    return function(v, build) {
      if (v === undefined) {
        return this._parts[_part] || '';
      } else {
        if (v !== null) {
          v = v + '';
          if (v.charAt(0) === _key) {
            v = v.substring(1);
          }
        }

        this._parts[_part] = v;
        this.build(!build);
        return this;
      }
    };
  }

  p.protocol = generateSimpleAccessor('protocol');
  p.username = generateSimpleAccessor('username');
  p.password = generateSimpleAccessor('password');
  p.hostname = generateSimpleAccessor('hostname');
  p.port = generateSimpleAccessor('port');
  p.query = generatePrefixAccessor('query', '?');
  p.fragment = generatePrefixAccessor('fragment', '#');

  p.search = function(v, build) {
    var t = this.query(v, build);
    return typeof t === 'string' && t.length ? ('?' + t) : t;
  };
  p.hash = function(v, build) {
    var t = this.fragment(v, build);
    return typeof t === 'string' && t.length ? ('#' + t) : t;
  };

  p.pathname = function(v, build) {
    if (v === undefined || v === true) {
      var res = this._parts.path || (this._parts.hostname ? '/' : '');
      return v ? (this._parts.urn ? URI.decodeUrnPath : URI.decodePath)(res) : res;
    } else {
      if (this._parts.urn) {
        this._parts.path = v ? URI.recodeUrnPath(v) : '';
      } else {
        this._parts.path = v ? URI.recodePath(v) : '/';
      }
      this.build(!build);
      return this;
    }
  };
  p.path = p.pathname;
  p.href = function(href, build) {
    var key;

    if (href === undefined) {
      return this.toString();
    }

    this._string = '';
    this._parts = URI._parts();

    var _URI = href instanceof URI;
    var _object = typeof href === 'object' && (href.hostname || href.path || href.pathname);
    if (href.nodeName) {
      var attribute = URI.getDomAttribute(href);
      href = href[attribute] || '';
      _object = false;
    }

    // window.location is reported to be an object, but it's not the sort
    // of object we're looking for:
    // * location.protocol ends with a colon
    // * location.query != object.search
    // * location.hash != object.fragment
    // simply serializing the unknown object should do the trick
    // (for location, not for everything...)
    if (!_URI && _object && href.pathname !== undefined) {
      href = href.toString();
    }

    if (typeof href === 'string' || href instanceof String) {
      this._parts = URI.parse(String(href), this._parts);
    } else if (_URI || _object) {
      var src = _URI ? href._parts : href;
      for (key in src) {
        if (key === 'query') { continue; }
        if (hasOwn.call(this._parts, key)) {
          this._parts[key] = src[key];
        }
      }
      if (src.query) {
        this.query(src.query, false);
      }
    } else {
      throw new TypeError('invalid input');
    }

    this.build(!build);
    return this;
  };

  // identification accessors
  p.is = function(what) {
    var ip = false;
    var ip4 = false;
    var ip6 = false;
    var name = false;
    var sld = false;
    var idn = false;
    var punycode = false;
    var relative = !this._parts.urn;

    if (this._parts.hostname) {
      relative = false;
      ip4 = URI.ip4_expression.test(this._parts.hostname);
      ip6 = URI.ip6_expression.test(this._parts.hostname);
      ip = ip4 || ip6;
      name = !ip;
      sld = name && SLD && SLD.has(this._parts.hostname);
      idn = name && URI.idn_expression.test(this._parts.hostname);
      punycode = name && URI.punycode_expression.test(this._parts.hostname);
    }

    switch (what.toLowerCase()) {
      case 'relative':
        return relative;

      case 'absolute':
        return !relative;

      // hostname identification
      case 'domain':
      case 'name':
        return name;

      case 'sld':
        return sld;

      case 'ip':
        return ip;

      case 'ip4':
      case 'ipv4':
      case 'inet4':
        return ip4;

      case 'ip6':
      case 'ipv6':
      case 'inet6':
        return ip6;

      case 'idn':
        return idn;

      case 'url':
        return !this._parts.urn;

      case 'urn':
        return !!this._parts.urn;

      case 'punycode':
        return punycode;
    }

    return null;
  };

  // component specific input validation
  var _protocol = p.protocol;
  var _port = p.port;
  var _hostname = p.hostname;

  p.protocol = function(v, build) {
    if (v) {
      // accept trailing ://
      v = v.replace(/:(\/\/)?$/, '');

      if (!v.match(URI.protocol_expression)) {
        throw new TypeError('Protocol "' + v + '" contains characters other than [A-Z0-9.+-] or doesn\'t start with [A-Z]');
      }
    }

    return _protocol.call(this, v, build);
  };
  p.scheme = p.protocol;
  p.port = function(v, build) {
    if (this._parts.urn) {
      return v === undefined ? '' : this;
    }

    if (v !== undefined) {
      if (v === 0) {
        v = null;
      }

      if (v) {
        v += '';
        if (v.charAt(0) === ':') {
          v = v.substring(1);
        }

        URI.ensureValidPort(v);
      }
    }
    return _port.call(this, v, build);
  };
  p.hostname = function(v, build) {
    if (this._parts.urn) {
      return v === undefined ? '' : this;
    }

    if (v !== undefined) {
      var x = { preventInvalidHostname: this._parts.preventInvalidHostname };
      var res = URI.parseHost(v, x);
      if (res !== '/') {
        throw new TypeError('Hostname "' + v + '" contains characters other than [A-Z0-9.-]');
      }

      v = x.hostname;
      if (this._parts.preventInvalidHostname) {
        URI.ensureValidHostname(v, this._parts.protocol);
      }
    }

    return _hostname.call(this, v, build);
  };

  // compound accessors
  p.origin = function(v, build) {
    if (this._parts.urn) {
      return v === undefined ? '' : this;
    }

    if (v === undefined) {
      var protocol = this.protocol();
      var authority = this.authority();
      if (!authority) {
        return '';
      }

      return (protocol ? protocol + '://' : '') + this.authority();
    } else {
      var origin = URI(v);
      this
        .protocol(origin.protocol())
        .authority(origin.authority())
        .build(!build);
      return this;
    }
  };
  p.host = function(v, build) {
    if (this._parts.urn) {
      return v === undefined ? '' : this;
    }

    if (v === undefined) {
      return this._parts.hostname ? URI.buildHost(this._parts) : '';
    } else {
      var res = URI.parseHost(v, this._parts);
      if (res !== '/') {
        throw new TypeError('Hostname "' + v + '" contains characters other than [A-Z0-9.-]');
      }

      this.build(!build);
      return this;
    }
  };
  p.authority = function(v, build) {
    if (this._parts.urn) {
      return v === undefined ? '' : this;
    }

    if (v === undefined) {
      return this._parts.hostname ? URI.buildAuthority(this._parts) : '';
    } else {
      var res = URI.parseAuthority(v, this._parts);
      if (res !== '/') {
        throw new TypeError('Hostname "' + v + '" contains characters other than [A-Z0-9.-]');
      }

      this.build(!build);
      return this;
    }
  };
  p.userinfo = function(v, build) {
    if (this._parts.urn) {
      return v === undefined ? '' : this;
    }

    if (v === undefined) {
      var t = URI.buildUserinfo(this._parts);
      return t ? t.substring(0, t.length -1) : t;
    } else {
      if (v[v.length-1] !== '@') {
        v += '@';
      }

      URI.parseUserinfo(v, this._parts);
      this.build(!build);
      return this;
    }
  };
  p.resource = function(v, build) {
    var parts;

    if (v === undefined) {
      return this.path() + this.search() + this.hash();
    }

    parts = URI.parse(v);
    this._parts.path = parts.path;
    this._parts.query = parts.query;
    this._parts.fragment = parts.fragment;
    this.build(!build);
    return this;
  };

  // fraction accessors
  p.subdomain = function(v, build) {
    if (this._parts.urn) {
      return v === undefined ? '' : this;
    }

    // convenience, return "www" from "www.example.org"
    if (v === undefined) {
      if (!this._parts.hostname || this.is('IP')) {
        return '';
      }

      // grab domain and add another segment
      var end = this._parts.hostname.length - this.domain().length - 1;
      return this._parts.hostname.substring(0, end) || '';
    } else {
      var e = this._parts.hostname.length - this.domain().length;
      var sub = this._parts.hostname.substring(0, e);
      var replace = new RegExp('^' + escapeRegEx(sub));

      if (v && v.charAt(v.length - 1) !== '.') {
        v += '.';
      }

      if (v.indexOf(':') !== -1) {
        throw new TypeError('Domains cannot contain colons');
      }

      if (v) {
        URI.ensureValidHostname(v, this._parts.protocol);
      }

      this._parts.hostname = this._parts.hostname.replace(replace, v);
      this.build(!build);
      return this;
    }
  };
  p.domain = function(v, build) {
    if (this._parts.urn) {
      return v === undefined ? '' : this;
    }

    if (typeof v === 'boolean') {
      build = v;
      v = undefined;
    }

    // convenience, return "example.org" from "www.example.org"
    if (v === undefined) {
      if (!this._parts.hostname || this.is('IP')) {
        return '';
      }

      // if hostname consists of 1 or 2 segments, it must be the domain
      var t = this._parts.hostname.match(/\./g);
      if (t && t.length < 2) {
        return this._parts.hostname;
      }

      // grab tld and add another segment
      var end = this._parts.hostname.length - this.tld(build).length - 1;
      end = this._parts.hostname.lastIndexOf('.', end -1) + 1;
      return this._parts.hostname.substring(end) || '';
    } else {
      if (!v) {
        throw new TypeError('cannot set domain empty');
      }

      if (v.indexOf(':') !== -1) {
        throw new TypeError('Domains cannot contain colons');
      }

      URI.ensureValidHostname(v, this._parts.protocol);

      if (!this._parts.hostname || this.is('IP')) {
        this._parts.hostname = v;
      } else {
        var replace = new RegExp(escapeRegEx(this.domain()) + '$');
        this._parts.hostname = this._parts.hostname.replace(replace, v);
      }

      this.build(!build);
      return this;
    }
  };
  p.tld = function(v, build) {
    if (this._parts.urn) {
      return v === undefined ? '' : this;
    }

    if (typeof v === 'boolean') {
      build = v;
      v = undefined;
    }

    // return "org" from "www.example.org"
    if (v === undefined) {
      if (!this._parts.hostname || this.is('IP')) {
        return '';
      }

      var pos = this._parts.hostname.lastIndexOf('.');
      var tld = this._parts.hostname.substring(pos + 1);

      if (build !== true && SLD && SLD.list[tld.toLowerCase()]) {
        return SLD.get(this._parts.hostname) || tld;
      }

      return tld;
    } else {
      var replace;

      if (!v) {
        throw new TypeError('cannot set TLD empty');
      } else if (v.match(/[^a-zA-Z0-9-]/)) {
        if (SLD && SLD.is(v)) {
          replace = new RegExp(escapeRegEx(this.tld()) + '$');
          this._parts.hostname = this._parts.hostname.replace(replace, v);
        } else {
          throw new TypeError('TLD "' + v + '" contains characters other than [A-Z0-9]');
        }
      } else if (!this._parts.hostname || this.is('IP')) {
        throw new ReferenceError('cannot set TLD on non-domain host');
      } else {
        replace = new RegExp(escapeRegEx(this.tld()) + '$');
        this._parts.hostname = this._parts.hostname.replace(replace, v);
      }

      this.build(!build);
      return this;
    }
  };
  p.directory = function(v, build) {
    if (this._parts.urn) {
      return v === undefined ? '' : this;
    }

    if (v === undefined || v === true) {
      if (!this._parts.path && !this._parts.hostname) {
        return '';
      }

      if (this._parts.path === '/') {
        return '/';
      }

      var end = this._parts.path.length - this.filename().length - 1;
      var res = this._parts.path.substring(0, end) || (this._parts.hostname ? '/' : '');

      return v ? URI.decodePath(res) : res;

    } else {
      var e = this._parts.path.length - this.filename().length;
      var directory = this._parts.path.substring(0, e);
      var replace = new RegExp('^' + escapeRegEx(directory));

      // fully qualifier directories begin with a slash
      if (!this.is('relative')) {
        if (!v) {
          v = '/';
        }

        if (v.charAt(0) !== '/') {
          v = '/' + v;
        }
      }

      // directories always end with a slash
      if (v && v.charAt(v.length - 1) !== '/') {
        v += '/';
      }

      v = URI.recodePath(v);
      this._parts.path = this._parts.path.replace(replace, v);
      this.build(!build);
      return this;
    }
  };
  p.filename = function(v, build) {
    if (this._parts.urn) {
      return v === undefined ? '' : this;
    }

    if (typeof v !== 'string') {
      if (!this._parts.path || this._parts.path === '/') {
        return '';
      }

      var pos = this._parts.path.lastIndexOf('/');
      var res = this._parts.path.substring(pos+1);

      return v ? URI.decodePathSegment(res) : res;
    } else {
      var mutatedDirectory = false;

      if (v.charAt(0) === '/') {
        v = v.substring(1);
      }

      if (v.match(/\.?\//)) {
        mutatedDirectory = true;
      }

      var replace = new RegExp(escapeRegEx(this.filename()) + '$');
      v = URI.recodePath(v);
      this._parts.path = this._parts.path.replace(replace, v);

      if (mutatedDirectory) {
        this.normalizePath(build);
      } else {
        this.build(!build);
      }

      return this;
    }
  };
  p.suffix = function(v, build) {
    if (this._parts.urn) {
      return v === undefined ? '' : this;
    }

    if (v === undefined || v === true) {
      if (!this._parts.path || this._parts.path === '/') {
        return '';
      }

      var filename = this.filename();
      var pos = filename.lastIndexOf('.');
      var s, res;

      if (pos === -1) {
        return '';
      }

      // suffix may only contain alnum characters (yup, I made this up.)
      s = filename.substring(pos+1);
      res = (/^[a-z0-9%]+$/i).test(s) ? s : '';
      return v ? URI.decodePathSegment(res) : res;
    } else {
      if (v.charAt(0) === '.') {
        v = v.substring(1);
      }

      var suffix = this.suffix();
      var replace;

      if (!suffix) {
        if (!v) {
          return this;
        }

        this._parts.path += '.' + URI.recodePath(v);
      } else if (!v) {
        replace = new RegExp(escapeRegEx('.' + suffix) + '$');
      } else {
        replace = new RegExp(escapeRegEx(suffix) + '$');
      }

      if (replace) {
        v = URI.recodePath(v);
        this._parts.path = this._parts.path.replace(replace, v);
      }

      this.build(!build);
      return this;
    }
  };
  p.segment = function(segment, v, build) {
    var separator = this._parts.urn ? ':' : '/';
    var path = this.path();
    var absolute = path.substring(0, 1) === '/';
    var segments = path.split(separator);

    if (segment !== undefined && typeof segment !== 'number') {
      build = v;
      v = segment;
      segment = undefined;
    }

    if (segment !== undefined && typeof segment !== 'number') {
      throw new Error('Bad segment "' + segment + '", must be 0-based integer');
    }

    if (absolute) {
      segments.shift();
    }

    if (segment < 0) {
      // allow negative indexes to address from the end
      segment = Math.max(segments.length + segment, 0);
    }

    if (v === undefined) {
      /*jshint laxbreak: true */
      return segment === undefined
        ? segments
        : segments[segment];
      /*jshint laxbreak: false */
    } else if (segment === null || segments[segment] === undefined) {
      if (isArray(v)) {
        segments = [];
        // collapse empty elements within array
        for (var i=0, l=v.length; i < l; i++) {
          if (!v[i].length && (!segments.length || !segments[segments.length -1].length)) {
            continue;
          }

          if (segments.length && !segments[segments.length -1].length) {
            segments.pop();
          }

          segments.push(trimSlashes(v[i]));
        }
      } else if (v || typeof v === 'string') {
        v = trimSlashes(v);
        if (segments[segments.length -1] === '') {
          // empty trailing elements have to be overwritten
          // to prevent results such as /foo//bar
          segments[segments.length -1] = v;
        } else {
          segments.push(v);
        }
      }
    } else {
      if (v) {
        segments[segment] = trimSlashes(v);
      } else {
        segments.splice(segment, 1);
      }
    }

    if (absolute) {
      segments.unshift('');
    }

    return this.path(segments.join(separator), build);
  };
  p.segmentCoded = function(segment, v, build) {
    var segments, i, l;

    if (typeof segment !== 'number') {
      build = v;
      v = segment;
      segment = undefined;
    }

    if (v === undefined) {
      segments = this.segment(segment, v, build);
      if (!isArray(segments)) {
        segments = segments !== undefined ? URI.decode(segments) : undefined;
      } else {
        for (i = 0, l = segments.length; i < l; i++) {
          segments[i] = URI.decode(segments[i]);
        }
      }

      return segments;
    }

    if (!isArray(v)) {
      v = (typeof v === 'string' || v instanceof String) ? URI.encode(v) : v;
    } else {
      for (i = 0, l = v.length; i < l; i++) {
        v[i] = URI.encode(v[i]);
      }
    }

    return this.segment(segment, v, build);
  };

  // mutating query string
  var q = p.query;
  p.query = function(v, build) {
    if (v === true) {
      return URI.parseQuery(this._parts.query, this._parts.escapeQuerySpace);
    } else if (typeof v === 'function') {
      var data = URI.parseQuery(this._parts.query, this._parts.escapeQuerySpace);
      var result = v.call(this, data);
      this._parts.query = URI.buildQuery(result || data, this._parts.duplicateQueryParameters, this._parts.escapeQuerySpace);
      this.build(!build);
      return this;
    } else if (v !== undefined && typeof v !== 'string') {
      this._parts.query = URI.buildQuery(v, this._parts.duplicateQueryParameters, this._parts.escapeQuerySpace);
      this.build(!build);
      return this;
    } else {
      return q.call(this, v, build);
    }
  };
  p.setQuery = function(name, value, build) {
    var data = URI.parseQuery(this._parts.query, this._parts.escapeQuerySpace);

    if (typeof name === 'string' || name instanceof String) {
      data[name] = value !== undefined ? value : null;
    } else if (typeof name === 'object') {
      for (var key in name) {
        if (hasOwn.call(name, key)) {
          data[key] = name[key];
        }
      }
    } else {
      throw new TypeError('URI.addQuery() accepts an object, string as the name parameter');
    }

    this._parts.query = URI.buildQuery(data, this._parts.duplicateQueryParameters, this._parts.escapeQuerySpace);
    if (typeof name !== 'string') {
      build = value;
    }

    this.build(!build);
    return this;
  };
  p.addQuery = function(name, value, build) {
    var data = URI.parseQuery(this._parts.query, this._parts.escapeQuerySpace);
    URI.addQuery(data, name, value === undefined ? null : value);
    this._parts.query = URI.buildQuery(data, this._parts.duplicateQueryParameters, this._parts.escapeQuerySpace);
    if (typeof name !== 'string') {
      build = value;
    }

    this.build(!build);
    return this;
  };
  p.removeQuery = function(name, value, build) {
    var data = URI.parseQuery(this._parts.query, this._parts.escapeQuerySpace);
    URI.removeQuery(data, name, value);
    this._parts.query = URI.buildQuery(data, this._parts.duplicateQueryParameters, this._parts.escapeQuerySpace);
    if (typeof name !== 'string') {
      build = value;
    }

    this.build(!build);
    return this;
  };
  p.hasQuery = function(name, value, withinArray) {
    var data = URI.parseQuery(this._parts.query, this._parts.escapeQuerySpace);
    return URI.hasQuery(data, name, value, withinArray);
  };
  p.setSearch = p.setQuery;
  p.addSearch = p.addQuery;
  p.removeSearch = p.removeQuery;
  p.hasSearch = p.hasQuery;

  // sanitizing URLs
  p.normalize = function() {
    if (this._parts.urn) {
      return this
        .normalizeProtocol(false)
        .normalizePath(false)
        .normalizeQuery(false)
        .normalizeFragment(false)
        .build();
    }

    return this
      .normalizeProtocol(false)
      .normalizeHostname(false)
      .normalizePort(false)
      .normalizePath(false)
      .normalizeQuery(false)
      .normalizeFragment(false)
      .build();
  };
  p.normalizeProtocol = function(build) {
    if (typeof this._parts.protocol === 'string') {
      this._parts.protocol = this._parts.protocol.toLowerCase();
      this.build(!build);
    }

    return this;
  };
  p.normalizeHostname = function(build) {
    if (this._parts.hostname) {
      if (this.is('IDN') && punycode) {
        this._parts.hostname = punycode.toASCII(this._parts.hostname);
      } else if (this.is('IPv6') && IPv6) {
        this._parts.hostname = IPv6.best(this._parts.hostname);
      }

      this._parts.hostname = this._parts.hostname.toLowerCase();
      this.build(!build);
    }

    return this;
  };
  p.normalizePort = function(build) {
    // remove port of it's the protocol's default
    if (typeof this._parts.protocol === 'string' && this._parts.port === URI.defaultPorts[this._parts.protocol]) {
      this._parts.port = null;
      this.build(!build);
    }

    return this;
  };
  p.normalizePath = function(build) {
    var _path = this._parts.path;
    if (!_path) {
      return this;
    }

    if (this._parts.urn) {
      this._parts.path = URI.recodeUrnPath(this._parts.path);
      this.build(!build);
      return this;
    }

    if (this._parts.path === '/') {
      return this;
    }

    _path = URI.recodePath(_path);

    var _was_relative;
    var _leadingParents = '';
    var _parent, _pos;

    // handle relative paths
    if (_path.charAt(0) !== '/') {
      _was_relative = true;
      _path = '/' + _path;
    }

    // handle relative files (as opposed to directories)
    if (_path.slice(-3) === '/..' || _path.slice(-2) === '/.') {
      _path += '/';
    }

    // resolve simples
    _path = _path
      .replace(/(\/(\.\/)+)|(\/\.$)/g, '/')
      .replace(/\/{2,}/g, '/');

    // remember leading parents
    if (_was_relative) {
      _leadingParents = _path.substring(1).match(/^(\.\.\/)+/) || '';
      if (_leadingParents) {
        _leadingParents = _leadingParents[0];
      }
    }

    // resolve parents
    while (true) {
      _parent = _path.search(/\/\.\.(\/|$)/);
      if (_parent === -1) {
        // no more ../ to resolve
        break;
      } else if (_parent === 0) {
        // top level cannot be relative, skip it
        _path = _path.substring(3);
        continue;
      }

      _pos = _path.substring(0, _parent).lastIndexOf('/');
      if (_pos === -1) {
        _pos = _parent;
      }
      _path = _path.substring(0, _pos) + _path.substring(_parent + 3);
    }

    // revert to relative
    if (_was_relative && this.is('relative')) {
      _path = _leadingParents + _path.substring(1);
    }

    this._parts.path = _path;
    this.build(!build);
    return this;
  };
  p.normalizePathname = p.normalizePath;
  p.normalizeQuery = function(build) {
    if (typeof this._parts.query === 'string') {
      if (!this._parts.query.length) {
        this._parts.query = null;
      } else {
        this.query(URI.parseQuery(this._parts.query, this._parts.escapeQuerySpace));
      }

      this.build(!build);
    }

    return this;
  };
  p.normalizeFragment = function(build) {
    if (!this._parts.fragment) {
      this._parts.fragment = null;
      this.build(!build);
    }

    return this;
  };
  p.normalizeSearch = p.normalizeQuery;
  p.normalizeHash = p.normalizeFragment;

  p.iso8859 = function() {
    // expect unicode input, iso8859 output
    var e = URI.encode;
    var d = URI.decode;

    URI.encode = escape;
    URI.decode = decodeURIComponent;
    try {
      this.normalize();
    } finally {
      URI.encode = e;
      URI.decode = d;
    }
    return this;
  };

  p.unicode = function() {
    // expect iso8859 input, unicode output
    var e = URI.encode;
    var d = URI.decode;

    URI.encode = strictEncodeURIComponent;
    URI.decode = unescape;
    try {
      this.normalize();
    } finally {
      URI.encode = e;
      URI.decode = d;
    }
    return this;
  };

  p.readable = function() {
    var uri = this.clone();
    // removing username, password, because they shouldn't be displayed according to RFC 3986
    uri.username('').password('').normalize();
    var t = '';
    if (uri._parts.protocol) {
      t += uri._parts.protocol + '://';
    }

    if (uri._parts.hostname) {
      if (uri.is('punycode') && punycode) {
        t += punycode.toUnicode(uri._parts.hostname);
        if (uri._parts.port) {
          t += ':' + uri._parts.port;
        }
      } else {
        t += uri.host();
      }
    }

    if (uri._parts.hostname && uri._parts.path && uri._parts.path.charAt(0) !== '/') {
      t += '/';
    }

    t += uri.path(true);
    if (uri._parts.query) {
      var q = '';
      for (var i = 0, qp = uri._parts.query.split('&'), l = qp.length; i < l; i++) {
        var kv = (qp[i] || '').split('=');
        q += '&' + URI.decodeQuery(kv[0], this._parts.escapeQuerySpace)
          .replace(/&/g, '%26');

        if (kv[1] !== undefined) {
          q += '=' + URI.decodeQuery(kv[1], this._parts.escapeQuerySpace)
            .replace(/&/g, '%26');
        }
      }
      t += '?' + q.substring(1);
    }

    t += URI.decodeQuery(uri.hash(), true);
    return t;
  };

  // resolving relative and absolute URLs
  p.absoluteTo = function(base) {
    var resolved = this.clone();
    var properties = ['protocol', 'username', 'password', 'hostname', 'port'];
    var basedir, i, p;

    if (this._parts.urn) {
      throw new Error('URNs do not have any generally defined hierarchical components');
    }

    if (!(base instanceof URI)) {
      base = new URI(base);
    }

    if (resolved._parts.protocol) {
      // Directly returns even if this._parts.hostname is empty.
      return resolved;
    } else {
      resolved._parts.protocol = base._parts.protocol;
    }

    if (this._parts.hostname) {
      return resolved;
    }

    for (i = 0; (p = properties[i]); i++) {
      resolved._parts[p] = base._parts[p];
    }

    if (!resolved._parts.path) {
      resolved._parts.path = base._parts.path;
      if (!resolved._parts.query) {
        resolved._parts.query = base._parts.query;
      }
    } else {
      if (resolved._parts.path.substring(-2) === '..') {
        resolved._parts.path += '/';
      }

      if (resolved.path().charAt(0) !== '/') {
        basedir = base.directory();
        basedir = basedir ? basedir : base.path().indexOf('/') === 0 ? '/' : '';
        resolved._parts.path = (basedir ? (basedir + '/') : '') + resolved._parts.path;
        resolved.normalizePath();
      }
    }

    resolved.build();
    return resolved;
  };
  p.relativeTo = function(base) {
    var relative = this.clone().normalize();
    var relativeParts, baseParts, common, relativePath, basePath;

    if (relative._parts.urn) {
      throw new Error('URNs do not have any generally defined hierarchical components');
    }

    base = new URI(base).normalize();
    relativeParts = relative._parts;
    baseParts = base._parts;
    relativePath = relative.path();
    basePath = base.path();

    if (relativePath.charAt(0) !== '/') {
      throw new Error('URI is already relative');
    }

    if (basePath.charAt(0) !== '/') {
      throw new Error('Cannot calculate a URI relative to another relative URI');
    }

    if (relativeParts.protocol === baseParts.protocol) {
      relativeParts.protocol = null;
    }

    if (relativeParts.username !== baseParts.username || relativeParts.password !== baseParts.password) {
      return relative.build();
    }

    if (relativeParts.protocol !== null || relativeParts.username !== null || relativeParts.password !== null) {
      return relative.build();
    }

    if (relativeParts.hostname === baseParts.hostname && relativeParts.port === baseParts.port) {
      relativeParts.hostname = null;
      relativeParts.port = null;
    } else {
      return relative.build();
    }

    if (relativePath === basePath) {
      relativeParts.path = '';
      return relative.build();
    }

    // determine common sub path
    common = URI.commonPath(relativePath, basePath);

    // If the paths have nothing in common, return a relative URL with the absolute path.
    if (!common) {
      return relative.build();
    }

    var parents = baseParts.path
      .substring(common.length)
      .replace(/[^\/]*$/, '')
      .replace(/.*?\//g, '../');

    relativeParts.path = (parents + relativeParts.path.substring(common.length)) || './';

    return relative.build();
  };

  // comparing URIs
  p.equals = function(uri) {
    var one = this.clone();
    var two = new URI(uri);
    var one_map = {};
    var two_map = {};
    var checked = {};
    var one_query, two_query, key;

    one.normalize();
    two.normalize();

    // exact match
    if (one.toString() === two.toString()) {
      return true;
    }

    // extract query string
    one_query = one.query();
    two_query = two.query();
    one.query('');
    two.query('');

    // definitely not equal if not even non-query parts match
    if (one.toString() !== two.toString()) {
      return false;
    }

    // query parameters have the same length, even if they're permuted
    if (one_query.length !== two_query.length) {
      return false;
    }

    one_map = URI.parseQuery(one_query, this._parts.escapeQuerySpace);
    two_map = URI.parseQuery(two_query, this._parts.escapeQuerySpace);

    for (key in one_map) {
      if (hasOwn.call(one_map, key)) {
        if (!isArray(one_map[key])) {
          if (one_map[key] !== two_map[key]) {
            return false;
          }
        } else if (!arraysEqual(one_map[key], two_map[key])) {
          return false;
        }

        checked[key] = true;
      }
    }

    for (key in two_map) {
      if (hasOwn.call(two_map, key)) {
        if (!checked[key]) {
          // two contains a parameter not present in one
          return false;
        }
      }
    }

    return true;
  };

  // state
  p.preventInvalidHostname = function(v) {
    this._parts.preventInvalidHostname = !!v;
    return this;
  };

  p.duplicateQueryParameters = function(v) {
    this._parts.duplicateQueryParameters = !!v;
    return this;
  };

  p.escapeQuerySpace = function(v) {
    this._parts.escapeQuerySpace = !!v;
    return this;
  };

  return URI;
}));