RobotDaily/node_modules/sax/lib/sax.js

;(function (sax) {
  // wrapper for non-node envs
  sax.parser = function (strict, opt) {
    return new SAXParser(strict, opt)
  }
  sax.SAXParser = SAXParser
  sax.SAXStream = SAXStream
  sax.createStream = createStream

  // When we pass the MAX_BUFFER_LENGTH position, start checking for buffer overruns.
  // When we check, schedule the next check for MAX_BUFFER_LENGTH - (max(buffer lengths)),
  // since that's the earliest that a buffer overrun could occur.  This way, checks are
  // as rare as required, but as often as necessary to ensure never crossing this bound.
  // Furthermore, buffers are only tested at most once per write(), so passing a very
  // large string into write() might have undesirable effects, but this is manageable by
  // the caller, so it is assumed to be safe.  Thus, a call to write() may, in the extreme
  // edge case, result in creating at most one complete copy of the string passed in.
  // Set to Infinity to have unlimited buffers.
  sax.MAX_BUFFER_LENGTH = 64 * 1024

  var buffers = [
    'comment',
    'sgmlDecl',
    'textNode',
    'tagName',
    'doctype',
    'procInstName',
    'procInstBody',
    'entity',
    'attribName',
    'attribValue',
    'cdata',
    'script',
  ]

  sax.EVENTS = [
    'text',
    'processinginstruction',
    'sgmldeclaration',
    'doctype',
    'comment',
    'opentagstart',
    'attribute',
    'opentag',
    'closetag',
    'opencdata',
    'cdata',
    'closecdata',
    'error',
    'end',
    'ready',
    'script',
    'opennamespace',
    'closenamespace',
  ]

  function SAXParser(strict, opt) {
    if (!(this instanceof SAXParser)) {
      return new SAXParser(strict, opt)
    }

    var parser = this
    clearBuffers(parser)
    parser.q = parser.c = ''
    parser.bufferCheckPosition = sax.MAX_BUFFER_LENGTH
    parser.opt = opt || {}
    parser.opt.lowercase = parser.opt.lowercase || parser.opt.lowercasetags
    parser.looseCase = parser.opt.lowercase ? 'toLowerCase' : 'toUpperCase'
    parser.tags = []
    parser.closed = parser.closedRoot = parser.sawRoot = false
    parser.tag = parser.error = null
    parser.strict = !!strict
    parser.noscript = !!(strict || parser.opt.noscript)
    parser.state = S.BEGIN
    parser.strictEntities = parser.opt.strictEntities
    parser.ENTITIES =
      parser.strictEntities ?
        Object.create(sax.XML_ENTITIES)
      : Object.create(sax.ENTITIES)
    parser.attribList = []

    // namespaces form a prototype chain.
    // it always points at the current tag,
    // which protos to its parent tag.
    if (parser.opt.xmlns) {
      parser.ns = Object.create(rootNS)
    }

    // disallow unquoted attribute values if not otherwise configured
    // and strict mode is true
    if (parser.opt.unquotedAttributeValues === undefined) {
      parser.opt.unquotedAttributeValues = !strict
    }

    // mostly just for error reporting
    parser.trackPosition = parser.opt.position !== false
    if (parser.trackPosition) {
      parser.position = parser.line = parser.column = 0
    }
    emit(parser, 'onready')
  }

  if (!Object.create) {
    Object.create = function (o) {
      function F() {}
      F.prototype = o
      var newf = new F()
      return newf
    }
  }

  if (!Object.keys) {
    Object.keys = function (o) {
      var a = []
      for (var i in o) if (o.hasOwnProperty(i)) a.push(i)
      return a
    }
  }

  function checkBufferLength(parser) {
    var maxAllowed = Math.max(sax.MAX_BUFFER_LENGTH, 10)
    var maxActual = 0
    for (var i = 0, l = buffers.length; i < l; i++) {
      var len = parser[buffers[i]].length
      if (len > maxAllowed) {
        // Text/cdata nodes can get big, and since they're buffered,
        // we can get here under normal conditions.
        // Avoid issues by emitting the text node now,
        // so at least it won't get any bigger.
        switch (buffers[i]) {
          case 'textNode':
            closeText(parser)
            break

          case 'cdata':
            emitNode(parser, 'oncdata', parser.cdata)
            parser.cdata = ''
            break

          case 'script':
            emitNode(parser, 'onscript', parser.script)
            parser.script = ''
            break

          default:
            error(parser, 'Max buffer length exceeded: ' + buffers[i])
        }
      }
      maxActual = Math.max(maxActual, len)
    }
    // schedule the next check for the earliest possible buffer overrun.
    var m = sax.MAX_BUFFER_LENGTH - maxActual
    parser.bufferCheckPosition = m + parser.position
  }

  function clearBuffers(parser) {
    for (var i = 0, l = buffers.length; i < l; i++) {
      parser[buffers[i]] = ''
    }
  }

  function flushBuffers(parser) {
    closeText(parser)
    if (parser.cdata !== '') {
      emitNode(parser, 'oncdata', parser.cdata)
      parser.cdata = ''
    }
    if (parser.script !== '') {
      emitNode(parser, 'onscript', parser.script)
      parser.script = ''
    }
  }

  SAXParser.prototype = {
    end: function () {
      end(this)
    },
    write: write,
    resume: function () {
      this.error = null
      return this
    },
    close: function () {
      return this.write(null)
    },
    flush: function () {
      flushBuffers(this)
    },
  }

  var Stream
  try {
    Stream = require('stream').Stream
  } catch (ex) {
    Stream = function () {}
  }
  if (!Stream) Stream = function () {}

  var streamWraps = sax.EVENTS.filter(function (ev) {
    return ev !== 'error' && ev !== 'end'
  })

  function createStream(strict, opt) {
    return new SAXStream(strict, opt)
  }

  function SAXStream(strict, opt) {
    if (!(this instanceof SAXStream)) {
      return new SAXStream(strict, opt)
    }

    Stream.apply(this)

    this._parser = new SAXParser(strict, opt)
    this.writable = true
    this.readable = true

    var me = this

    this._parser.onend = function () {
      me.emit('end')
    }

    this._parser.onerror = function (er) {
      me.emit('error', er)

      // if didn't throw, then means error was handled.
      // go ahead and clear error, so we can write again.
      me._parser.error = null
    }

    this._decoder = null

    streamWraps.forEach(function (ev) {
      Object.defineProperty(me, 'on' + ev, {
        get: function () {
          return me._parser['on' + ev]
        },
        set: function (h) {
          if (!h) {
            me.removeAllListeners(ev)
            me._parser['on' + ev] = h
            return h
          }
          me.on(ev, h)
        },
        enumerable: true,
        configurable: false,
      })
    })
  }

  SAXStream.prototype = Object.create(Stream.prototype, {
    constructor: {
      value: SAXStream,
    },
  })

  SAXStream.prototype.write = function (data) {
    if (
      typeof Buffer === 'function' &&
      typeof Buffer.isBuffer === 'function' &&
      Buffer.isBuffer(data)
    ) {
      if (!this._decoder) {
        this._decoder = new TextDecoder('utf8')
      }
      data = this._decoder.decode(data, { stream: true })
    }

    this._parser.write(data.toString())
    this.emit('data', data)
    return true
  }

  SAXStream.prototype.end = function (chunk) {
    if (chunk && chunk.length) {
      this.write(chunk)
    }
    // Flush any remaining decoded data from the TextDecoder
    if (this._decoder) {
      var remaining = this._decoder.decode()
      if (remaining) {
        this._parser.write(remaining)
        this.emit('data', remaining)
      }
    }
    this._parser.end()
    return true
  }

  SAXStream.prototype.on = function (ev, handler) {
    var me = this
    if (!me._parser['on' + ev] && streamWraps.indexOf(ev) !== -1) {
      me._parser['on' + ev] = function () {
        var args =
          arguments.length === 1 ?
            [arguments[0]]
          : Array.apply(null, arguments)
        args.splice(0, 0, ev)
        me.emit.apply(me, args)
      }
    }

    return Stream.prototype.on.call(me, ev, handler)
  }

  // this really needs to be replaced with character classes.
  // XML allows all manner of ridiculous numbers and digits.
  var CDATA = '[CDATA['
  var DOCTYPE = 'DOCTYPE'
  var XML_NAMESPACE = 'http://www.w3.org/XML/1998/namespace'
  var XMLNS_NAMESPACE = 'http://www.w3.org/2000/xmlns/'
  var rootNS = { xml: XML_NAMESPACE, xmlns: XMLNS_NAMESPACE }

  // http://www.w3.org/TR/REC-xml/#NT-NameStartChar
  // This implementation works on strings, a single character at a time
  // as such, it cannot ever support astral-plane characters (10000-EFFFF)
  // without a significant breaking change to either this  parser, or the
  // JavaScript language.  Implementation of an emoji-capable xml parser
  // is left as an exercise for the reader.
  var nameStart =
    /[:_A-Za-z\u00C0-\u00D6\u00D8-\u00F6\u00F8-\u02FF\u0370-\u037D\u037F-\u1FFF\u200C-\u200D\u2070-\u218F\u2C00-\u2FEF\u3001-\uD7FF\uF900-\uFDCF\uFDF0-\uFFFD]/

  var nameBody =
    /[:_A-Za-z\u00C0-\u00D6\u00D8-\u00F6\u00F8-\u02FF\u0370-\u037D\u037F-\u1FFF\u200C-\u200D\u2070-\u218F\u2C00-\u2FEF\u3001-\uD7FF\uF900-\uFDCF\uFDF0-\uFFFD\u00B7\u0300-\u036F\u203F-\u2040.\d-]/

  var entityStart =
    /[#:_A-Za-z\u00C0-\u00D6\u00D8-\u00F6\u00F8-\u02FF\u0370-\u037D\u037F-\u1FFF\u200C-\u200D\u2070-\u218F\u2C00-\u2FEF\u3001-\uD7FF\uF900-\uFDCF\uFDF0-\uFFFD]/
  var entityBody =
    /[#:_A-Za-z\u00C0-\u00D6\u00D8-\u00F6\u00F8-\u02FF\u0370-\u037D\u037F-\u1FFF\u200C-\u200D\u2070-\u218F\u2C00-\u2FEF\u3001-\uD7FF\uF900-\uFDCF\uFDF0-\uFFFD\u00B7\u0300-\u036F\u203F-\u2040.\d-]/

  function isWhitespace(c) {
    return c === ' ' || c === '\n' || c === '\r' || c === '\t'
  }

  function isQuote(c) {
    return c === '"' || c === "'"
  }

  function isAttribEnd(c) {
    return c === '>' || isWhitespace(c)
  }

  function isMatch(regex, c) {
    return regex.test(c)
  }

  function notMatch(regex, c) {
    return !isMatch(regex, c)
  }

  var S = 0
  sax.STATE = {
    BEGIN: S++, // leading byte order mark or whitespace
    BEGIN_WHITESPACE: S++, // leading whitespace
    TEXT: S++, // general stuff
    TEXT_ENTITY: S++, // &amp and such.
    OPEN_WAKA: S++, // <
    SGML_DECL: S++, // <!BLARG
    SGML_DECL_QUOTED: S++, // <!BLARG foo "bar
    DOCTYPE: S++, // <!DOCTYPE
    DOCTYPE_QUOTED: S++, // <!DOCTYPE "//blah
    DOCTYPE_DTD: S++, // <!DOCTYPE "//blah" [ ...
    DOCTYPE_DTD_QUOTED: S++, // <!DOCTYPE "//blah" [ "foo
    COMMENT_STARTING: S++, // <!-
    COMMENT: S++, // <!--
    COMMENT_ENDING: S++, // <!-- blah -
    COMMENT_ENDED: S++, // <!-- blah --
    CDATA: S++, // <![CDATA[ something
    CDATA_ENDING: S++, // ]
    CDATA_ENDING_2: S++, // ]]
    PROC_INST: S++, // <?hi
    PROC_INST_BODY: S++, // <?hi there
    PROC_INST_ENDING: S++, // <?hi "there" ?
    OPEN_TAG: S++, // <strong
    OPEN_TAG_SLASH: S++, // <strong /
    ATTRIB: S++, // <a
    ATTRIB_NAME: S++, // <a foo
    ATTRIB_NAME_SAW_WHITE: S++, // <a foo _
    ATTRIB_VALUE: S++, // <a foo=
    ATTRIB_VALUE_QUOTED: S++, // <a foo="bar
    ATTRIB_VALUE_CLOSED: S++, // <a foo="bar"
    ATTRIB_VALUE_UNQUOTED: S++, // <a foo=bar
    ATTRIB_VALUE_ENTITY_Q: S++, // <foo bar="&quot;"
    ATTRIB_VALUE_ENTITY_U: S++, // <foo bar=&quot
    CLOSE_TAG: S++, // </a
    CLOSE_TAG_SAW_WHITE: S++, // </a   >
    SCRIPT: S++, // <script> ...
    SCRIPT_ENDING: S++, // <script> ... <
  }

  sax.XML_ENTITIES = {
    amp: '&',
    gt: '>',
    lt: '<',
    quot: '"',
    apos: "'",
  }

  sax.ENTITIES = {
    amp: '&',
    gt: '>',
    lt: '<',
    quot: '"',
    apos: "'",
    AElig: 198,
    Aacute: 193,
    Acirc: 194,
    Agrave: 192,
    Aring: 197,
    Atilde: 195,
    Auml: 196,
    Ccedil: 199,
    ETH: 208,
    Eacute: 201,
    Ecirc: 202,
    Egrave: 200,
    Euml: 203,
    Iacute: 205,
    Icirc: 206,
    Igrave: 204,
    Iuml: 207,
    Ntilde: 209,
    Oacute: 211,
    Ocirc: 212,
    Ograve: 210,
    Oslash: 216,
    Otilde: 213,
    Ouml: 214,
    THORN: 222,
    Uacute: 218,
    Ucirc: 219,
    Ugrave: 217,
    Uuml: 220,
    Yacute: 221,
    aacute: 225,
    acirc: 226,
    aelig: 230,
    agrave: 224,
    aring: 229,
    atilde: 227,
    auml: 228,
    ccedil: 231,
    eacute: 233,
    ecirc: 234,
    egrave: 232,
    eth: 240,
    euml: 235,
    iacute: 237,
    icirc: 238,
    igrave: 236,
    iuml: 239,
    ntilde: 241,
    oacute: 243,
    ocirc: 244,
    ograve: 242,
    oslash: 248,
    otilde: 245,
    ouml: 246,
    szlig: 223,
    thorn: 254,
    uacute: 250,
    ucirc: 251,
    ugrave: 249,
    uuml: 252,
    yacute: 253,
    yuml: 255,
    copy: 169,
    reg: 174,
    nbsp: 160,
    iexcl: 161,
    cent: 162,
    pound: 163,
    curren: 164,
    yen: 165,
    brvbar: 166,
    sect: 167,
    uml: 168,
    ordf: 170,
    laquo: 171,
    not: 172,
    shy: 173,
    macr: 175,
    deg: 176,
    plusmn: 177,
    sup1: 185,
    sup2: 178,
    sup3: 179,
    acute: 180,
    micro: 181,
    para: 182,
    middot: 183,
    cedil: 184,
    ordm: 186,
    raquo: 187,
    frac14: 188,
    frac12: 189,
    frac34: 190,
    iquest: 191,
    times: 215,
    divide: 247,
    OElig: 338,
    oelig: 339,
    Scaron: 352,
    scaron: 353,
    Yuml: 376,
    fnof: 402,
    circ: 710,
    tilde: 732,
    Alpha: 913,
    Beta: 914,
    Gamma: 915,
    Delta: 916,
    Epsilon: 917,
    Zeta: 918,
    Eta: 919,
    Theta: 920,
    Iota: 921,
    Kappa: 922,
    Lambda: 923,
    Mu: 924,
    Nu: 925,
    Xi: 926,
    Omicron: 927,
    Pi: 928,
    Rho: 929,
    Sigma: 931,
    Tau: 932,
    Upsilon: 933,
    Phi: 934,
    Chi: 935,
    Psi: 936,
    Omega: 937,
    alpha: 945,
    beta: 946,
    gamma: 947,
    delta: 948,
    epsilon: 949,
    zeta: 950,
    eta: 951,
    theta: 952,
    iota: 953,
    kappa: 954,
    lambda: 955,
    mu: 956,
    nu: 957,
    xi: 958,
    omicron: 959,
    pi: 960,
    rho: 961,
    sigmaf: 962,
    sigma: 963,
    tau: 964,
    upsilon: 965,
    phi: 966,
    chi: 967,
    psi: 968,
    omega: 969,
    thetasym: 977,
    upsih: 978,
    piv: 982,
    ensp: 8194,
    emsp: 8195,
    thinsp: 8201,
    zwnj: 8204,
    zwj: 8205,
    lrm: 8206,
    rlm: 8207,
    ndash: 8211,
    mdash: 8212,
    lsquo: 8216,
    rsquo: 8217,
    sbquo: 8218,
    ldquo: 8220,
    rdquo: 8221,
    bdquo: 8222,
    dagger: 8224,
    Dagger: 8225,
    bull: 8226,
    hellip: 8230,
    permil: 8240,
    prime: 8242,
    Prime: 8243,
    lsaquo: 8249,
    rsaquo: 8250,
    oline: 8254,
    frasl: 8260,
    euro: 8364,
    image: 8465,
    weierp: 8472,
    real: 8476,
    trade: 8482,
    alefsym: 8501,
    larr: 8592,
    uarr: 8593,
    rarr: 8594,
    darr: 8595,
    harr: 8596,
    crarr: 8629,
    lArr: 8656,
    uArr: 8657,
    rArr: 8658,
    dArr: 8659,
    hArr: 8660,
    forall: 8704,
    part: 8706,
    exist: 8707,
    empty: 8709,
    nabla: 8711,
    isin: 8712,
    notin: 8713,
    ni: 8715,
    prod: 8719,
    sum: 8721,
    minus: 8722,
    lowast: 8727,
    radic: 8730,
    prop: 8733,
    infin: 8734,
    ang: 8736,
    and: 8743,
    or: 8744,
    cap: 8745,
    cup: 8746,
    int: 8747,
    there4: 8756,
    sim: 8764,
    cong: 8773,
    asymp: 8776,
    ne: 8800,
    equiv: 8801,
    le: 8804,
    ge: 8805,
    sub: 8834,
    sup: 8835,
    nsub: 8836,
    sube: 8838,
    supe: 8839,
    oplus: 8853,
    otimes: 8855,
    perp: 8869,
    sdot: 8901,
    lceil: 8968,
    rceil: 8969,
    lfloor: 8970,
    rfloor: 8971,
    lang: 9001,
    rang: 9002,
    loz: 9674,
    spades: 9824,
    clubs: 9827,
    hearts: 9829,
    diams: 9830,
  }

  Object.keys(sax.ENTITIES).forEach(function (key) {
    var e = sax.ENTITIES[key]
    var s = typeof e === 'number' ? String.fromCharCode(e) : e
    sax.ENTITIES[key] = s
  })

  for (var s in sax.STATE) {
    sax.STATE[sax.STATE[s]] = s
  }

  // shorthand
  S = sax.STATE

  function emit(parser, event, data) {
    parser[event] && parser[event](data)
  }

  function emitNode(parser, nodeType, data) {
    if (parser.textNode) closeText(parser)
    emit(parser, nodeType, data)
  }

  function closeText(parser) {
    parser.textNode = textopts(parser.opt, parser.textNode)
    if (parser.textNode) emit(parser, 'ontext', parser.textNode)
    parser.textNode = ''
  }

  function textopts(opt, text) {
    if (opt.trim) text = text.trim()
    if (opt.normalize) text = text.replace(/\s+/g, ' ')
    return text
  }

  function error(parser, er) {
    closeText(parser)
    if (parser.trackPosition) {
      er +=
        '\nLine: ' +
        parser.line +
        '\nColumn: ' +
        parser.column +
        '\nChar: ' +
        parser.c
    }
    er = new Error(er)
    parser.error = er
    emit(parser, 'onerror', er)
    return parser
  }

  function end(parser) {
    if (parser.sawRoot && !parser.closedRoot)
      strictFail(parser, 'Unclosed root tag')
    if (
      parser.state !== S.BEGIN &&
      parser.state !== S.BEGIN_WHITESPACE &&
      parser.state !== S.TEXT
    ) {
      error(parser, 'Unexpected end')
    }
    closeText(parser)
    parser.c = ''
    parser.closed = true
    emit(parser, 'onend')
    SAXParser.call(parser, parser.strict, parser.opt)
    return parser
  }

  function strictFail(parser, message) {
    if (typeof parser !== 'object' || !(parser instanceof SAXParser)) {
      throw new Error('bad call to strictFail')
    }
    if (parser.strict) {
      error(parser, message)
    }
  }

  function newTag(parser) {
    if (!parser.strict) parser.tagName = parser.tagName[parser.looseCase]()
    var parent = parser.tags[parser.tags.length - 1] || parser
    var tag = (parser.tag = { name: parser.tagName, attributes: {} })

    // will be overridden if tag contails an xmlns="foo" or xmlns:foo="bar"
    if (parser.opt.xmlns) {
      tag.ns = parent.ns
    }
    parser.attribList.length = 0
    emitNode(parser, 'onopentagstart', tag)
  }

  function qname(name, attribute) {
    var i = name.indexOf(':')
    var qualName = i < 0 ? ['', name] : name.split(':')
    var prefix = qualName[0]
    var local = qualName[1]

    // <x "xmlns"="http://foo">
    if (attribute && name === 'xmlns') {
      prefix = 'xmlns'
      local = ''
    }

    return { prefix: prefix, local: local }
  }

  function attrib(parser) {
    if (!parser.strict) {
      parser.attribName = parser.attribName[parser.looseCase]()
    }

    if (
      parser.attribList.indexOf(parser.attribName) !== -1 ||
      parser.tag.attributes.hasOwnProperty(parser.attribName)
    ) {
      parser.attribName = parser.attribValue = ''
      return
    }

    if (parser.opt.xmlns) {
      var qn = qname(parser.attribName, true)
      var prefix = qn.prefix
      var local = qn.local

      if (prefix === 'xmlns') {
        // namespace binding attribute. push the binding into scope
        if (local === 'xml' && parser.attribValue !== XML_NAMESPACE) {
          strictFail(
            parser,
            'xml: prefix must be bound to ' +
              XML_NAMESPACE +
              '\n' +
              'Actual: ' +
              parser.attribValue
          )
        } else if (
          local === 'xmlns' &&
          parser.attribValue !== XMLNS_NAMESPACE
        ) {
          strictFail(
            parser,
            'xmlns: prefix must be bound to ' +
              XMLNS_NAMESPACE +
              '\n' +
              'Actual: ' +
              parser.attribValue
          )
        } else {
          var tag = parser.tag
          var parent = parser.tags[parser.tags.length - 1] || parser
          if (tag.ns === parent.ns) {
            tag.ns = Object.create(parent.ns)
          }
          tag.ns[local] = parser.attribValue
        }
      }

      // defer onattribute events until all attributes have been seen
      // so any new bindings can take effect. preserve attribute order
      // so deferred events can be emitted in document order
      parser.attribList.push([parser.attribName, parser.attribValue])
    } else {
      // in non-xmlns mode, we can emit the event right away
      parser.tag.attributes[parser.attribName] = parser.attribValue
      emitNode(parser, 'onattribute', {
        name: parser.attribName,
        value: parser.attribValue,
      })
    }

    parser.attribName = parser.attribValue = ''
  }

  function openTag(parser, selfClosing) {
    if (parser.opt.xmlns) {
      // emit namespace binding events
      var tag = parser.tag

      // add namespace info to tag
      var qn = qname(parser.tagName)
      tag.prefix = qn.prefix
      tag.local = qn.local
      tag.uri = tag.ns[qn.prefix] || ''

      if (tag.prefix && !tag.uri) {
        strictFail(
          parser,
          'Unbound namespace prefix: ' + JSON.stringify(parser.tagName)
        )
        tag.uri = qn.prefix
      }

      var parent = parser.tags[parser.tags.length - 1] || parser
      if (tag.ns && parent.ns !== tag.ns) {
        Object.keys(tag.ns).forEach(function (p) {
          emitNode(parser, 'onopennamespace', {
            prefix: p,
            uri: tag.ns[p],
          })
        })
      }

      // handle deferred onattribute events
      // Note: do not apply default ns to attributes:
      //   http://www.w3.org/TR/REC-xml-names/#defaulting
      for (var i = 0, l = parser.attribList.length; i < l; i++) {
        var nv = parser.attribList[i]
        var name = nv[0]
        var value = nv[1]
        var qualName = qname(name, true)
        var prefix = qualName.prefix
        var local = qualName.local
        var uri = prefix === '' ? '' : tag.ns[prefix] || ''
        var a = {
          name: name,
          value: value,
          prefix: prefix,
          local: local,
          uri: uri,
        }

        // if there's any attributes with an undefined namespace,
        // then fail on them now.
        if (prefix && prefix !== 'xmlns' && !uri) {
          strictFail(
            parser,
            'Unbound namespace prefix: ' + JSON.stringify(prefix)
          )
          a.uri = prefix
        }
        parser.tag.attributes[name] = a
        emitNode(parser, 'onattribute', a)
      }
      parser.attribList.length = 0
    }

    parser.tag.isSelfClosing = !!selfClosing

    // process the tag
    parser.sawRoot = true
    parser.tags.push(parser.tag)
    emitNode(parser, 'onopentag', parser.tag)
    if (!selfClosing) {
      // special case for <script> in non-strict mode.
      if (!parser.noscript && parser.tagName.toLowerCase() === 'script') {
        parser.state = S.SCRIPT
      } else {
        parser.state = S.TEXT
      }
      parser.tag = null
      parser.tagName = ''
    }
    parser.attribName = parser.attribValue = ''
    parser.attribList.length = 0
  }

  function closeTag(parser) {
    if (!parser.tagName) {
      strictFail(parser, 'Weird empty close tag.')
      parser.textNode += '</>'
      parser.state = S.TEXT
      return
    }

    if (parser.script) {
      if (parser.tagName !== 'script') {
        parser.script += '</' + parser.tagName + '>'
        parser.tagName = ''
        parser.state = S.SCRIPT
        return
      }
      emitNode(parser, 'onscript', parser.script)
      parser.script = ''
    }

    // first make sure that the closing tag actually exists.
    // <a><b></c></b></a> will close everything, otherwise.
    var t = parser.tags.length
    var tagName = parser.tagName
    if (!parser.strict) {
      tagName = tagName[parser.looseCase]()
    }
    var closeTo = tagName
    while (t--) {
      var close = parser.tags[t]
      if (close.name !== closeTo) {
        // fail the first time in strict mode
        strictFail(parser, 'Unexpected close tag')
      } else {
        break
      }
    }

    // didn't find it.  we already failed for strict, so just abort.
    if (t < 0) {
      strictFail(parser, 'Unmatched closing tag: ' + parser.tagName)
      parser.textNode += '</' + parser.tagName + '>'
      parser.state = S.TEXT
      return
    }
    parser.tagName = tagName
    var s = parser.tags.length
    while (s-- > t) {
      var tag = (parser.tag = parser.tags.pop())
      parser.tagName = parser.tag.name
      emitNode(parser, 'onclosetag', parser.tagName)

      var x = {}
      for (var i in tag.ns) {
        x[i] = tag.ns[i]
      }

      var parent = parser.tags[parser.tags.length - 1] || parser
      if (parser.opt.xmlns && tag.ns !== parent.ns) {
        // remove namespace bindings introduced by tag
        Object.keys(tag.ns).forEach(function (p) {
          var n = tag.ns[p]
          emitNode(parser, 'onclosenamespace', { prefix: p, uri: n })
        })
      }
    }
    if (t === 0) parser.closedRoot = true
    parser.tagName = parser.attribValue = parser.attribName = ''
    parser.attribList.length = 0
    parser.state = S.TEXT
  }

  function parseEntity(parser) {
    var entity = parser.entity
    var entityLC = entity.toLowerCase()
    var num
    var numStr = ''

    if (parser.ENTITIES[entity]) {
      return parser.ENTITIES[entity]
    }
    if (parser.ENTITIES[entityLC]) {
      return parser.ENTITIES[entityLC]
    }
    entity = entityLC
    if (entity.charAt(0) === '#') {
      if (entity.charAt(1) === 'x') {
        entity = entity.slice(2)
        num = parseInt(entity, 16)
        numStr = num.toString(16)
      } else {
        entity = entity.slice(1)
        num = parseInt(entity, 10)
        numStr = num.toString(10)
      }
    }
    entity = entity.replace(/^0+/, '')
    if (
      isNaN(num) ||
      numStr.toLowerCase() !== entity ||
      num < 0 ||
      num > 0x10ffff
    ) {
      strictFail(parser, 'Invalid character entity')
      return '&' + parser.entity + ';'
    }

    return String.fromCodePoint(num)
  }

  function beginWhiteSpace(parser, c) {
    if (c === '<') {
      parser.state = S.OPEN_WAKA
      parser.startTagPosition = parser.position
    } else if (!isWhitespace(c)) {
      // have to process this as a text node.
      // weird, but happens.
      strictFail(parser, 'Non-whitespace before first tag.')
      parser.textNode = c
      parser.state = S.TEXT
    }
  }

  function charAt(chunk, i) {
    var result = ''
    if (i < chunk.length) {
      result = chunk.charAt(i)
    }
    return result
  }

  function write(chunk) {
    var parser = this
    if (this.error) {
      throw this.error
    }
    if (parser.closed) {
      return error(
        parser,
        'Cannot write after close. Assign an onready handler.'
      )
    }
    if (chunk === null) {
      return end(parser)
    }
    if (typeof chunk === 'object') {
      chunk = chunk.toString()
    }
    var i = 0
    var c = ''
    while (true) {
      c = charAt(chunk, i++)
      parser.c = c

      if (!c) {
        break
      }

      if (parser.trackPosition) {
        parser.position++
        if (c === '\n') {
          parser.line++
          parser.column = 0
        } else {
          parser.column++
        }
      }

      switch (parser.state) {
        case S.BEGIN:
          parser.state = S.BEGIN_WHITESPACE
          if (c === '\uFEFF') {
            continue
          }
          beginWhiteSpace(parser, c)
          continue

        case S.BEGIN_WHITESPACE:
          beginWhiteSpace(parser, c)
          continue

        case S.TEXT:
          if (parser.sawRoot && !parser.closedRoot) {
            var starti = i - 1
            while (c && c !== '<' && c !== '&') {
              c = charAt(chunk, i++)
              if (c && parser.trackPosition) {
                parser.position++
                if (c === '\n') {
                  parser.line++
                  parser.column = 0
                } else {
                  parser.column++
                }
              }
            }
            parser.textNode += chunk.substring(starti, i - 1)
          }
          if (
            c === '<' &&
            !(parser.sawRoot && parser.closedRoot && !parser.strict)
          ) {
            parser.state = S.OPEN_WAKA
            parser.startTagPosition = parser.position
          } else {
            if (
              !isWhitespace(c) &&
              (!parser.sawRoot || parser.closedRoot)
            ) {
              strictFail(parser, 'Text data outside of root node.')
            }
            if (c === '&') {
              parser.state = S.TEXT_ENTITY
            } else {
              parser.textNode += c
            }
          }
          continue

        case S.SCRIPT:
          // only non-strict
          if (c === '<') {
            parser.state = S.SCRIPT_ENDING
          } else {
            parser.script += c
          }
          continue

        case S.SCRIPT_ENDING:
          if (c === '/') {
            parser.state = S.CLOSE_TAG
          } else {
            parser.script += '<' + c
            parser.state = S.SCRIPT
          }
          continue

        case S.OPEN_WAKA:
          // either a /, ?, !, or text is coming next.
          if (c === '!') {
            parser.state = S.SGML_DECL
            parser.sgmlDecl = ''
          } else if (isWhitespace(c)) {
            // wait for it...
          } else if (isMatch(nameStart, c)) {
            parser.state = S.OPEN_TAG
            parser.tagName = c
          } else if (c === '/') {
            parser.state = S.CLOSE_TAG
            parser.tagName = ''
          } else if (c === '?') {
            parser.state = S.PROC_INST
            parser.procInstName = parser.procInstBody = ''
          } else {
            strictFail(parser, 'Unencoded <')
            // if there was some whitespace, then add that in.
            if (parser.startTagPosition + 1 < parser.position) {
              var pad = parser.position - parser.startTagPosition
              c = new Array(pad).join(' ') + c
            }
            parser.textNode += '<' + c
            parser.state = S.TEXT
          }
          continue

        case S.SGML_DECL:
          if (parser.sgmlDecl + c === '--') {
            parser.state = S.COMMENT
            parser.comment = ''
            parser.sgmlDecl = ''
            continue
          }

          if (
            parser.doctype &&
            parser.doctype !== true &&
            parser.sgmlDecl
          ) {
            parser.state = S.DOCTYPE_DTD
            parser.doctype += '<!' + parser.sgmlDecl + c
            parser.sgmlDecl = ''
          } else if ((parser.sgmlDecl + c).toUpperCase() === CDATA) {
            emitNode(parser, 'onopencdata')
            parser.state = S.CDATA
            parser.sgmlDecl = ''
            parser.cdata = ''
          } else if ((parser.sgmlDecl + c).toUpperCase() === DOCTYPE) {
            parser.state = S.DOCTYPE
            if (parser.doctype || parser.sawRoot) {
              strictFail(
                parser,
                'Inappropriately located doctype declaration'
              )
            }
            parser.doctype = ''
            parser.sgmlDecl = ''
          } else if (c === '>') {
            emitNode(parser, 'onsgmldeclaration', parser.sgmlDecl)
            parser.sgmlDecl = ''
            parser.state = S.TEXT
          } else if (isQuote(c)) {
            parser.state = S.SGML_DECL_QUOTED
            parser.sgmlDecl += c
          } else {
            parser.sgmlDecl += c
          }
          continue

        case S.SGML_DECL_QUOTED:
          if (c === parser.q) {
            parser.state = S.SGML_DECL
            parser.q = ''
          }
          parser.sgmlDecl += c
          continue

        case S.DOCTYPE:
          if (c === '>') {
            parser.state = S.TEXT
            emitNode(parser, 'ondoctype', parser.doctype)
            parser.doctype = true // just remember that we saw it.
          } else {
            parser.doctype += c
            if (c === '[') {
              parser.state = S.DOCTYPE_DTD
            } else if (isQuote(c)) {
              parser.state = S.DOCTYPE_QUOTED
              parser.q = c
            }
          }
          continue

        case S.DOCTYPE_QUOTED:
          parser.doctype += c
          if (c === parser.q) {
            parser.q = ''
            parser.state = S.DOCTYPE
          }
          continue

        case S.DOCTYPE_DTD:
          if (c === ']') {
            parser.doctype += c
            parser.state = S.DOCTYPE
          } else if (c === '<') {
            parser.state = S.OPEN_WAKA
            parser.startTagPosition = parser.position
          } else if (isQuote(c)) {
            parser.doctype += c
            parser.state = S.DOCTYPE_DTD_QUOTED
            parser.q = c
          } else {
            parser.doctype += c
          }
          continue

        case S.DOCTYPE_DTD_QUOTED:
          parser.doctype += c
          if (c === parser.q) {
            parser.state = S.DOCTYPE_DTD
            parser.q = ''
          }
          continue

        case S.COMMENT:
          if (c === '-') {
            parser.state = S.COMMENT_ENDING
          } else {
            parser.comment += c
          }
          continue

        case S.COMMENT_ENDING:
          if (c === '-') {
            parser.state = S.COMMENT_ENDED
            parser.comment = textopts(parser.opt, parser.comment)
            if (parser.comment) {
              emitNode(parser, 'oncomment', parser.comment)
            }
            parser.comment = ''
          } else {
            parser.comment += '-' + c
            parser.state = S.COMMENT
          }
          continue

        case S.COMMENT_ENDED:
          if (c !== '>') {
            strictFail(parser, 'Malformed comment')
            // allow <!-- blah -- bloo --> in non-strict mode,
            // which is a comment of " blah -- bloo "
            parser.comment += '--' + c
            parser.state = S.COMMENT
          } else if (parser.doctype && parser.doctype !== true) {
            parser.state = S.DOCTYPE_DTD
          } else {
            parser.state = S.TEXT
          }
          continue

        case S.CDATA:
          var starti = i - 1
          while (c && c !== ']') {
            c = charAt(chunk, i++)
            if (c && parser.trackPosition) {
              parser.position++
              if (c === '\n') {
                parser.line++
                parser.column = 0
              } else {
                parser.column++
              }
            }
          }
          parser.cdata += chunk.substring(starti, i - 1)
          if (c === ']') {
            parser.state = S.CDATA_ENDING
          }
          continue

        case S.CDATA_ENDING:
          if (c === ']') {
            parser.state = S.CDATA_ENDING_2
          } else {
            parser.cdata += ']' + c
            parser.state = S.CDATA
          }
          continue

        case S.CDATA_ENDING_2:
          if (c === '>') {
            if (parser.cdata) {
              emitNode(parser, 'oncdata', parser.cdata)
            }
            emitNode(parser, 'onclosecdata')
            parser.cdata = ''
            parser.state = S.TEXT
          } else if (c === ']') {
            parser.cdata += ']'
          } else {
            parser.cdata += ']]' + c
            parser.state = S.CDATA
          }
          continue

        case S.PROC_INST:
          if (c === '?') {
            parser.state = S.PROC_INST_ENDING
          } else if (isWhitespace(c)) {
            parser.state = S.PROC_INST_BODY
          } else {
            parser.procInstName += c
          }
          continue

        case S.PROC_INST_BODY:
          if (!parser.procInstBody && isWhitespace(c)) {
            continue
          } else if (c === '?') {
            parser.state = S.PROC_INST_ENDING
          } else {
            parser.procInstBody += c
          }
          continue

        case S.PROC_INST_ENDING:
          if (c === '>') {
            emitNode(parser, 'onprocessinginstruction', {
              name: parser.procInstName,
              body: parser.procInstBody,
            })
            parser.procInstName = parser.procInstBody = ''
            parser.state = S.TEXT
          } else {
            parser.procInstBody += '?' + c
            parser.state = S.PROC_INST_BODY
          }
          continue

        case S.OPEN_TAG:
          if (isMatch(nameBody, c)) {
            parser.tagName += c
          } else {
            newTag(parser)
            if (c === '>') {
              openTag(parser)
            } else if (c === '/') {
              parser.state = S.OPEN_TAG_SLASH
            } else {
              if (!isWhitespace(c)) {
                strictFail(parser, 'Invalid character in tag name')
              }
              parser.state = S.ATTRIB
            }
          }
          continue

        case S.OPEN_TAG_SLASH:
          if (c === '>') {
            openTag(parser, true)
            closeTag(parser)
          } else {
            strictFail(
              parser,
              'Forward-slash in opening tag not followed by >'
            )
            parser.state = S.ATTRIB
          }
          continue

        case S.ATTRIB:
          // haven't read the attribute name yet.
          if (isWhitespace(c)) {
            continue
          } else if (c === '>') {
            openTag(parser)
          } else if (c === '/') {
            parser.state = S.OPEN_TAG_SLASH
          } else if (isMatch(nameStart, c)) {
            parser.attribName = c
            parser.attribValue = ''
            parser.state = S.ATTRIB_NAME
          } else {
            strictFail(parser, 'Invalid attribute name')
          }
          continue

        case S.ATTRIB_NAME:
          if (c === '=') {
            parser.state = S.ATTRIB_VALUE
          } else if (c === '>') {
            strictFail(parser, 'Attribute without value')
            parser.attribValue = parser.attribName
            attrib(parser)
            openTag(parser)
          } else if (isWhitespace(c)) {
            parser.state = S.ATTRIB_NAME_SAW_WHITE
          } else if (isMatch(nameBody, c)) {
            parser.attribName += c
          } else {
            strictFail(parser, 'Invalid attribute name')
          }
          continue

        case S.ATTRIB_NAME_SAW_WHITE:
          if (c === '=') {
            parser.state = S.ATTRIB_VALUE
          } else if (isWhitespace(c)) {
            continue
          } else {
            strictFail(parser, 'Attribute without value')
            parser.tag.attributes[parser.attribName] = ''
            parser.attribValue = ''
            emitNode(parser, 'onattribute', {
              name: parser.attribName,
              value: '',
            })
            parser.attribName = ''
            if (c === '>') {
              openTag(parser)
            } else if (isMatch(nameStart, c)) {
              parser.attribName = c
              parser.state = S.ATTRIB_NAME
            } else {
              strictFail(parser, 'Invalid attribute name')
              parser.state = S.ATTRIB
            }
          }
          continue

        case S.ATTRIB_VALUE:
          if (isWhitespace(c)) {
            continue
          } else if (isQuote(c)) {
            parser.q = c
            parser.state = S.ATTRIB_VALUE_QUOTED
          } else {
            if (!parser.opt.unquotedAttributeValues) {
              error(parser, 'Unquoted attribute value')
            }
            parser.state = S.ATTRIB_VALUE_UNQUOTED
            parser.attribValue = c
          }
          continue

        case S.ATTRIB_VALUE_QUOTED:
          if (c !== parser.q) {
            if (c === '&') {
              parser.state = S.ATTRIB_VALUE_ENTITY_Q
            } else {
              parser.attribValue += c
            }
            continue
          }
          attrib(parser)
          parser.q = ''
          parser.state = S.ATTRIB_VALUE_CLOSED
          continue

        case S.ATTRIB_VALUE_CLOSED:
          if (isWhitespace(c)) {
            parser.state = S.ATTRIB
          } else if (c === '>') {
            openTag(parser)
          } else if (c === '/') {
            parser.state = S.OPEN_TAG_SLASH
          } else if (isMatch(nameStart, c)) {
            strictFail(parser, 'No whitespace between attributes')
            parser.attribName = c
            parser.attribValue = ''
            parser.state = S.ATTRIB_NAME
          } else {
            strictFail(parser, 'Invalid attribute name')
          }
          continue

        case S.ATTRIB_VALUE_UNQUOTED:
          if (!isAttribEnd(c)) {
            if (c === '&') {
              parser.state = S.ATTRIB_VALUE_ENTITY_U
            } else {
              parser.attribValue += c
            }
            continue
          }
          attrib(parser)
          if (c === '>') {
            openTag(parser)
          } else {
            parser.state = S.ATTRIB
          }
          continue

        case S.CLOSE_TAG:
          if (!parser.tagName) {
            if (isWhitespace(c)) {
              continue
            } else if (notMatch(nameStart, c)) {
              if (parser.script) {
                parser.script += '</' + c
                parser.state = S.SCRIPT
              } else {
                strictFail(parser, 'Invalid tagname in closing tag.')
              }
            } else {
              parser.tagName = c
            }
          } else if (c === '>') {
            closeTag(parser)
          } else if (isMatch(nameBody, c)) {
            parser.tagName += c
          } else if (parser.script) {
            parser.script += '</' + parser.tagName + c
            parser.tagName = ''
            parser.state = S.SCRIPT
          } else {
            if (!isWhitespace(c)) {
              strictFail(parser, 'Invalid tagname in closing tag')
            }
            parser.state = S.CLOSE_TAG_SAW_WHITE
          }
          continue

        case S.CLOSE_TAG_SAW_WHITE:
          if (isWhitespace(c)) {
            continue
          }
          if (c === '>') {
            closeTag(parser)
          } else {
            strictFail(parser, 'Invalid characters in closing tag')
          }
          continue

        case S.TEXT_ENTITY:
        case S.ATTRIB_VALUE_ENTITY_Q:
        case S.ATTRIB_VALUE_ENTITY_U:
          var returnState
          var buffer
          switch (parser.state) {
            case S.TEXT_ENTITY:
              returnState = S.TEXT
              buffer = 'textNode'
              break

            case S.ATTRIB_VALUE_ENTITY_Q:
              returnState = S.ATTRIB_VALUE_QUOTED
              buffer = 'attribValue'
              break

            case S.ATTRIB_VALUE_ENTITY_U:
              returnState = S.ATTRIB_VALUE_UNQUOTED
              buffer = 'attribValue'
              break
          }

          if (c === ';') {
            var parsedEntity = parseEntity(parser)
            if (
              parser.opt.unparsedEntities &&
              !Object.values(sax.XML_ENTITIES).includes(parsedEntity)
            ) {
              parser.entity = ''
              parser.state = returnState
              parser.write(parsedEntity)
            } else {
              parser[buffer] += parsedEntity
              parser.entity = ''
              parser.state = returnState
            }
          } else if (
            isMatch(parser.entity.length ? entityBody : entityStart, c)
          ) {
            parser.entity += c
          } else {
            strictFail(parser, 'Invalid character in entity name')
            parser[buffer] += '&' + parser.entity + c
            parser.entity = ''
            parser.state = returnState
          }

          continue

        default: /* istanbul ignore next */ {
          throw new Error(parser, 'Unknown state: ' + parser.state)
        }
      }
    } // while

    if (parser.position >= parser.bufferCheckPosition) {
      checkBufferLength(parser)
    }
    return parser
  }

  /*! http://mths.be/fromcodepoint v0.1.0 by @mathias */
  /* istanbul ignore next */
  if (!String.fromCodePoint) {
    ;(function () {
      var stringFromCharCode = String.fromCharCode
      var floor = Math.floor
      var fromCodePoint = function () {
        var MAX_SIZE = 0x4000
        var codeUnits = []
        var highSurrogate
        var lowSurrogate
        var index = -1
        var length = arguments.length
        if (!length) {
          return ''
        }
        var result = ''
        while (++index < length) {
          var codePoint = Number(arguments[index])
          if (
            !isFinite(codePoint) || // `NaN`, `+Infinity`, or `-Infinity`
            codePoint < 0 || // not a valid Unicode code point
            codePoint > 0x10ffff || // not a valid Unicode code point
            floor(codePoint) !== codePoint // not an integer
          ) {
            throw RangeError('Invalid code point: ' + codePoint)
          }
          if (codePoint <= 0xffff) {
            // BMP code point
            codeUnits.push(codePoint)
          } else {
            // Astral code point; split in surrogate halves
            // http://mathiasbynens.be/notes/javascript-encoding#surrogate-formulae
            codePoint -= 0x10000
            highSurrogate = (codePoint >> 10) + 0xd800
            lowSurrogate = (codePoint % 0x400) + 0xdc00
            codeUnits.push(highSurrogate, lowSurrogate)
          }
          if (index + 1 === length || codeUnits.length > MAX_SIZE) {
            result += stringFromCharCode.apply(null, codeUnits)
            codeUnits.length = 0
          }
        }
        return result
      }
      /* istanbul ignore next */
      if (Object.defineProperty) {
        Object.defineProperty(String, 'fromCodePoint', {
          value: fromCodePoint,
          configurable: true,
          writable: true,
        })
      } else {
        String.fromCodePoint = fromCodePoint
      }
    })()
  }
})(typeof exports === 'undefined' ? (this.sax = {}) : exports)