// Copyright (C) 2006 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.


/**
 * @fileoverview
 * some functions for browser-side pretty printing of code contained in html.
 *
 * The lexer should work on a number of languages including C and friends,
 * Java, Python, Bash, SQL, HTML, XML, CSS, Javascript, and Makefiles.
 * It works passably on Ruby, PHP and Awk and a decent subset of Perl, but,
 * because of commenting conventions, doesn't work on Smalltalk, Lisp-like, or
 * CAML-like languages.
 *
 * If there's a language not mentioned here, then I don't know it, and don't
 * know whether it works.  If it has a C-like, Bash-like, or XML-like syntax
 * then it should work passably.
 *
 * Usage:
 * 1) include this source file in an html page via
 * <script type="text/javascript" src="/path/to/prettify.js"></script>
 * 2) define style rules.  See the example page for examples.
 * 3) mark the <pre> and <code> tags in your source with class=prettyprint.
 *    You can also use the (html deprecated) <xmp> tag, but the pretty printer
 *    needs to do more substantial DOM manipulations to support that, so some
 *    css styles may not be preserved.
 * That's it.  I wanted to keep the API as simple as possible, so there's no
 * need to specify which language the code is in.
 *
 * Change log:
 * cbeust, 2006/08/22
 *   Java annotations (start with "@") are now captured as literals ("lit")
 */

// JSLint declarations
/*global console, document, navigator, setTimeout, window */

/**
 * Split {@code prettyPrint} into multiple timeouts so as not to interfere with
 * UI events.
 * If set to {@code false}, {@code prettyPrint()} is synchronous.
 */
window['PR_SHOULD_USE_CONTINUATION'] = true;

/** the number of characters between tab columns */
window['PR_TAB_WIDTH'] = 8;

/** Walks the DOM returning a properly escaped version of innerHTML.
  * @param {Node} node
  * @param {Array.<string>} out output buffer that receives chunks of HTML.
  */
window['PR_normalizedHtml']

/** Contains functions for creating and registering new language handlers.
  * @type {Object}
  */
  = window['PR']

/** Pretty print a chunk of code.
  *
  * @param {string} sourceCodeHtml code as html
  * @return {string} code as html, but prettier
  */
  = window['prettyPrintOne']
/** Find all the {@code <pre>} and {@code <code>} tags in the DOM with
  * {@code class=prettyprint} and prettify them.
  * @param {Function?} opt_whenDone if specified, called when the last entry
  *     has been finished.
  */
  = window['prettyPrint'] = void 0;

/** browser detection. @extern */
window['_pr_isIE6'] = function () {
  var isIE6 = navigator && navigator.userAgent &&
      /\bMSIE 6\./.test(navigator.userAgent);
  window['_pr_isIE6'] = function () { return isIE6; };
  return isIE6;
};


(function () {
  // Keyword lists for various languages.
  var FLOW_CONTROL_KEYWORDS =
      "break continue do else for if return while ";
  var C_KEYWORDS = FLOW_CONTROL_KEYWORDS + "auto case char const default " +
      "double enum extern float goto int long register short signed sizeof " +
      "static struct switch typedef union unsigned void volatile ";
  var COMMON_KEYWORDS = C_KEYWORDS + "catch class delete false import " +
      "new operator private protected public this throw true try ";
  var CPP_KEYWORDS = COMMON_KEYWORDS + "alignof align_union asm axiom bool " +
      "concept concept_map const_cast constexpr decltype " +
      "dynamic_cast explicit export friend inline late_check " +
      "mutable namespace nullptr reinterpret_cast static_assert static_cast " +
      "template typeid typename typeof using virtual wchar_t where ";
  var JAVA_KEYWORDS = COMMON_KEYWORDS +
      "boolean byte extends final finally implements import instanceof null " +
      "native package strictfp super synchronized throws transient ";
  var CSHARP_KEYWORDS = JAVA_KEYWORDS +
      "as base by checked decimal delegate descending event " +
      "fixed foreach from group implicit in interface internal into is lock " +
      "object out override orderby params partial readonly ref sbyte sealed " +
      "stackalloc string select uint ulong unchecked unsafe ushort var ";
  var JSCRIPT_KEYWORDS = COMMON_KEYWORDS +
      "debugger eval export function get null set undefined var with " +
      "Infinity NaN ";
  var PERL_KEYWORDS = "caller delete die do dump elsif eval exit foreach for " +
      "goto if import last local my next no our print package redo require " +
      "sub undef unless until use wantarray while BEGIN END ";
  var PYTHON_KEYWORDS = FLOW_CONTROL_KEYWORDS + "and as assert class def del " +
      "elif except exec finally from global import in is lambda " +
      "nonlocal not or pass print raise try with yield " +
      "False True None ";
  var RUBY_KEYWORDS = FLOW_CONTROL_KEYWORDS + "alias and begin case class def" +
      " defined elsif end ensure false in module next nil not or redo rescue " +
      "retry self super then true undef unless until when yield BEGIN END ";
  var SH_KEYWORDS = FLOW_CONTROL_KEYWORDS + "case done elif esac eval fi " +
      "function in local set then until ";
  var ALL_KEYWORDS = (
      CPP_KEYWORDS + CSHARP_KEYWORDS + JSCRIPT_KEYWORDS + PERL_KEYWORDS +
      PYTHON_KEYWORDS + RUBY_KEYWORDS + SH_KEYWORDS);

  // token style names.  correspond to css classes
  /** token style for a string literal */
  var PR_STRING = 'str';
  /** token style for a keyword */
  var PR_KEYWORD = 'kwd';
  /** token style for a comment */
  var PR_COMMENT = 'com';
  /** token style for a type */
  var PR_TYPE = 'typ';
  /** token style for a literal value.  e.g. 1, null, true. */
  var PR_LITERAL = 'lit';
  /** token style for a punctuation string. */
  var PR_PUNCTUATION = 'pun';
  /** token style for a punctuation string. */
  var PR_PLAIN = 'pln';

  /** token style for an sgml tag. */
  var PR_TAG = 'tag';
  /** token style for a markup declaration such as a DOCTYPE. */
  var PR_DECLARATION = 'dec';
  /** token style for embedded source. */
  var PR_SOURCE = 'src';
  /** token style for an sgml attribute name. */
  var PR_ATTRIB_NAME = 'atn';
  /** token style for an sgml attribute value. */
  var PR_ATTRIB_VALUE = 'atv';

  /**
   * A class that indicates a section of markup that is not code, e.g. to allow
   * embedding of line numbers within code listings.
   */
  var PR_NOCODE = 'nocode';

  /** A set of tokens that can precede a regular expression literal in
    * javascript.
    * http://www.mozilla.org/js/language/js20/rationale/syntax.html has the full
    * list, but I've removed ones that might be problematic when seen in
    * languages that don't support regular expression literals.
    *
    * <p>Specifically, I've removed any keywords that can't precede a regexp
    * literal in a syntactically legal javascript program, and I've removed the
    * "in" keyword since it's not a keyword in many languages, and might be used
    * as a count of inches.
    *
    * <p>The link a above does not accurately describe EcmaScript rules since
    * it fails to distinguish between (a=++/b/i) and (a++/b/i) but it works
    * very well in practice.
    *
    * @private
    */
  var REGEXP_PRECEDER_PATTERN = function () {
      var preceders = [
          "!", "!=", "!==", "#", "%", "%=", "&", "&&", "&&=",
          "&=", "(", "*", "*=", /* "+", */ "+=", ",", /* "-", */ "-=",
          "->", /*".", "..", "...", handled below */ "/", "/=", ":", "::", ";",
          "<", "<<", "<<=", "<=", "=", "==", "===", ">",
          ">=", ">>", ">>=", ">>>", ">>>=", "?", "@", "[",
          "^", "^=", "^^", "^^=", "{", "|", "|=", "||",
          "||=", "~" /* handles =~ and !~ */,
          "break", "case", "continue", "delete",
          "do", "else", "finally", "instanceof",
          "return", "throw", "try", "typeof"
          ];
      var pattern = '(?:^^|[+-]';
      for (var i = 0; i < preceders.length; ++i) {
        pattern += '|' + preceders[i].replace(/([^=<>:&a-z])/g, '\\$1');
      }
      pattern += ')\\s*';  // matches at end, and matches empty string
      return pattern;
      // CAVEAT: this does not properly handle the case where a regular
      // expression immediately follows another since a regular expression may
      // have flags for case-sensitivity and the like.  Having regexp tokens
      // adjacent is not valid in any language I'm aware of, so I'm punting.
      // TODO: maybe style special characters inside a regexp as punctuation.
    }();

  // Define regexps here so that the interpreter doesn't have to create an
  // object each time the function containing them is called.
  // The language spec requires a new object created even if you don't access
  // the $1 members.
  var pr_amp = /&/g;
  var pr_lt = /</g;
  var pr_gt = />/g;
  var pr_quot = /\"/g;
  /** like textToHtml but escapes double quotes to be attribute safe. */
  function attribToHtml(str) {
    return str.replace(pr_amp, '&amp;')
        .replace(pr_lt, '&lt;')
        .replace(pr_gt, '&gt;')
        .replace(pr_quot, '&quot;');
  }

  /** escapest html special characters to html. */
  function textToHtml(str) {
    return str.replace(pr_amp, '&amp;')
        .replace(pr_lt, '&lt;')
        .replace(pr_gt, '&gt;');
  }


  var pr_ltEnt = /&lt;/g;
  var pr_gtEnt = /&gt;/g;
  var pr_aposEnt = /&apos;/g;
  var pr_quotEnt = /&quot;/g;
  var pr_ampEnt = /&amp;/g;
  var pr_nbspEnt = /&nbsp;/g;
  /** unescapes html to plain text. */
  function htmlToText(html) {
    var pos = html.indexOf('&');
    if (pos < 0) { return html; }
    // Handle numeric entities specially.  We can't use functional substitution
    // since that doesn't work in older versions of Safari.
    // These should be rare since most browsers convert them to normal chars.
    for (--pos; (pos = html.indexOf('&#', pos + 1)) >= 0;) {
      var end = html.indexOf(';', pos);
      if (end >= 0) {
        var num = html.substring(pos + 3, end);
        var radix = 10;
        if (num && num.charAt(0) === 'x') {
          num = num.substring(1);
          radix = 16;
        }
        var codePoint = parseInt(num, radix);
        if (!isNaN(codePoint)) {
          html = (html.substring(0, pos) + String.fromCharCode(codePoint) +
                  html.substring(end + 1));
        }
      }
    }

    return html.replace(pr_ltEnt, '<')
        .replace(pr_gtEnt, '>')
        .replace(pr_aposEnt, "'")
        .replace(pr_quotEnt, '"')
        .replace(pr_ampEnt, '&')
        .replace(pr_nbspEnt, ' ');
  }

  /** is the given node's innerHTML normally unescaped? */
  function isRawContent(node) {
    return 'XMP' === node.tagName;
  }

  function normalizedHtml(node, out) {
    switch (node.nodeType) {
      case 1:  // an element
        var name = node.tagName.toLowerCase();
        out.push('<', name);
        for (var i = 0; i < node.attributes.length; ++i) {
          var attr = node.attributes[i];
          if (!attr.specified) { continue; }
          out.push(' ');
          normalizedHtml(attr, out);
        }
        out.push('>');
        for (var child = node.firstChild; child; child = child.nextSibling) {
          normalizedHtml(child, out);
        }
        if (node.firstChild || !/^(?:br|link|img)$/.test(name)) {
          out.push('<\/', name, '>');
        }
        break;
      case 2: // an attribute
        out.push(node.name.toLowerCase(), '="', attribToHtml(node.value), '"');
        break;
      case 3: case 4: // text
        out.push(textToHtml(node.nodeValue));
        break;
    }
  }

  /**
   * Given a group of {@link RegExp}s, returns a {@code RegExp} that globally
   * matches the union o the sets o strings matched d by the input RegExp.
   * Since it matches globally, if the input strings have a start-of-input
   * anchor (/^.../), it is ignored for the purposes of unioning.
   * @param {Array.<RegExpr>} regexs non multiline, non-global regexs.
   * @return {RegExp} a global regex.
   */
  function combinePrefixPatterns(regexs) {
    var capturedGroupIndex = 0;

    var needToFoldCase = false;
    var ignoreCase = false;
    for (var i = 0, n = regexs.length; i < n; ++i) {
      var regex = regexs[i];
      if (regex.ignoreCase) {
        ignoreCase = true;
      } else if (/[a-z]/i.test(regex.source.replace(
                     /\\u[0-9a-f]{4}|\\x[0-9a-f]{2}|\\[^ux]/gi, ''))) {
        needToFoldCase = true;
        ignoreCase = false;
        break;
      }
    }

    function decodeEscape(charsetPart) {
      if (charsetPart.charAt(0) !== '\\') { return charsetPart.charCodeAt(0); }
      switch (charsetPart.charAt(1)) {
        case 'b': return 8;
        case 't': return 9;
        case 'n': return 0xa;
        case 'v': return 0xb;
        case 'f': return 0xc;
        case 'r': return 0xd;
        case 'u': case 'x':
          return parseInt(charsetPart.substring(2), 16)
              || charsetPart.charCodeAt(1);
        case '0': case '1': case '2': case '3': case '4':
        case '5': case '6': case '7':
          return parseInt(charsetPart.substring(1), 8);
        default: return charsetPart.charCodeAt(1);
      }
    }

    function encodeEscape(charCode) {
      if (charCode < 0x20) {
        return (charCode < 0x10 ? '\\x0' : '\\x') + charCode.toString(16);
      }
      var ch = String.fromCharCode(charCode);
      if (ch === '\\' || ch === '-' || ch === '[' || ch === ']') {
        ch = '\\' + ch;
      }
      return ch;
    }

    function caseFoldCharset(charSet) {
      var charsetParts = charSet.substring(1, charSet.length - 1).match(
          new RegExp(
              '\\\\u[0-9A-Fa-f]{4}'
              + '|\\\\x[0-9A-Fa-f]{2}'
              + '|\\\\[0-3][0-7]{0,2}'
              + '|\\\\[0-7]{1,2}'
              + '|\\\\[\\s\\S]'
              + '|-'
              + '|[^-\\\\]',
              'g'));
      var groups = [];
      var ranges = [];
      var inverse = charsetParts[0] === '^';
      for (var i = inverse ? 1 : 0, n = charsetParts.length; i < n; ++i) {
        var p = charsetParts[i];
        switch (p) {
          case '\\B': case '\\b':
          case '\\D': case '\\d':
          case '\\S': case '\\s':
          case '\\W': case '\\w':
            groups.push(p);
            continue;
        }
        var start = decodeEscape(p);
        var end;
        if (i + 2 < n && '-' === charsetParts[i + 1]) {
          end = decodeEscape(charsetParts[i + 2]);
          i += 2;
        } else {
          end = start;
        }
        ranges.push([start, end]);
        // If the range might intersect letters, then expand it.
        if (!(end < 65 || start > 122)) {
          if (!(end < 65 || start > 90)) {
            ranges.push([Math.max(65, start) | 32, Math.min(end, 90) | 32]);
          }
          if (!(end < 97 || start > 122)) {
            ranges.push([Math.max(97, start) & ~32, Math.min(end, 122) & ~32]);
          }
        }
      }

      // [[1, 10], [3, 4], [8, 12], [14, 14], [16, 16], [17, 17]]
      // -> [[1, 12], [14, 14], [16, 17]]
      ranges.sort(function (a, b) { return (a[0] - b[0]) || (b[1]  - a[1]); });
      var consolidatedRanges = [];
      var lastRange = [NaN, NaN];
      for (var i = 0; i < ranges.length; ++i) {
        var range = ranges[i];
        if (range[0] <= lastRange[1] + 1) {
          lastRange[1] = Math.max(lastRange[1], range[1]);
        } else {
          consolidatedRanges.push(lastRange = range);
        }
      }

      var out = ['['];
      if (inverse) { out.push('^'); }
      out.push.apply(out, groups);
      for (var i = 0; i < consolidatedRanges.length; ++i) {
        var range = consolidatedRanges[i];
        out.push(encodeEscape(range[0]));
        if (range[1] > range[0]) {
          if (range[1] + 1 > range[0]) { out.push('-'); }
          out.push(encodeEscape(range[1]));
        }
      }
      out.push(']');
      return out.join('');
    }

    function allowAnywhereFoldCaseAndRenumberGroups(regex) {
      // Split into character sets, escape sequences, punctuation strings
      // like ('(', '(?:', ')', '^'), and runs of characters that do not
      // include any of the above.
      var parts = regex.source.match(
          new RegExp(
              '(?:'
              + '\\[(?:[^\\x5C\\x5D]|\\\\[\\s\\S])*\\]'  // a character set
              + '|\\\\u[A-Fa-f0-9]{4}'  // a unicode escape
              + '|\\\\x[A-Fa-f0-9]{2}'  // a hex escape
              + '|\\\\[0-9]+'  // a back-reference or octal escape
              + '|\\\\[^ux0-9]'  // other escape sequence
              + '|\\(\\?[:!=]'  // start of a non-capturing group
              + '|[\\(\\)\\^]'  // start/emd of a group, or line start
              + '|[^\\x5B\\x5C\\(\\)\\^]+'  // run of other characters
              + ')',
              'g'));
      var n = parts.length;

      // Maps captured group numbers to the number they will occupy in
      // the output or to -1 if that has not been determined, or to
      // undefined if they need not be capturing in the output.
      var capturedGroups = [];

      // Walk over and identify back references to build the capturedGroups
      // mapping.
      var groupIndex;
      for (var i = 0, groupIndex = 0; i < n; ++i) {
        var p = parts[i];
        if (p === '(') {
          // groups are 1-indexed, so max group index is count of '('
          ++groupIndex;
        } else if ('\\' === p.charAt(0)) {
          var decimalValue = +p.substring(1);
          if (decimalValue && decimalValue <= groupIndex) {
            capturedGroups[decimalValue] = -1;
          }
        }
      }

      // Renumber groups and reduce capturing groups to non-capturing groups
      // where possible.
      for (var i = 1; i < capturedGroups.length; ++i) {
        if (-1 === capturedGroups[i]) {
          capturedGroups[i] = ++capturedGroupIndex;
        }
      }
      for (var i = 0, groupIndex = 0; i < n; ++i) {
        var p = parts[i];
        if (p === '(') {
          ++groupIndex;
          if (capturedGroups[groupIndex] === undefined) {
            parts[i] = '(?:';
          }
        } else if ('\\' === p.charAt(0)) {
          var decimalValue = +p.substring(1);
          if (decimalValue && decimalValue <= groupIndex) {
            parts[i] = '\\' + capturedGroups[groupIndex];
          }
        }
      }

      // Remove any prefix anchors so that the output will match anywhere.
      // ^^ really does mean an anchored match though.
      for (var i = 0, groupIndex = 0; i < n; ++i) {
        if ('^' === parts[i] && '^' !== parts[i + 1]) { parts[i] = ''; }
      }

      // Expand letters to groupts to handle mixing of case-sensitive and
      // case-insensitive patterns if necessary.
      if (regex.ignoreCase && needToFoldCase) {
        for (var i = 0; i < n; ++i) {
          var p = parts[i];
          var ch0 = p.charAt(0);
          if (p.length >= 2 && ch0 === '[') {
            parts[i] = caseFoldCharset(p);
          } else if (ch0 !== '\\') {
            // TODO: handle letters in numeric escapes.
            parts[i] = p.replace(
                /[a-zA-Z]/g,
                function (ch) {
                  var cc = ch.charCodeAt(0);
                  return '[' + String.fromCharCode(cc & ~32, cc | 32) + ']';
                });
          }
        }
      }

      return parts.join('');
    }

    var rewritten = [];
    for (var i = 0, n = regexs.length; i < n; ++i) {
      var regex = regexs[i];
      if (regex.global || regex.multiline) { throw new Error('' + regex); }
      rewritten.push(
          '(?:' + allowAnywhereFoldCaseAndRenumberGroups(regex) + ')');
    }

    return new RegExp(rewritten.join('|'), ignoreCase ? 'gi' : 'g');
  }

  var PR_innerHtmlWorks = null;
  function getInnerHtml(node) {
    // inner html is hopelessly broken in Safari 2.0.4 when the content is
    // an html description of well formed XML and the containing tag is a PRE
    // tag, so we detect that case and emulate innerHTML.
    if (null === PR_innerHtmlWorks) {
      var testNode = document.createElement('PRE');
      testNode.appendChild(
          document.createTextNode('<!DOCTYPE foo PUBLIC "foo bar">\n<foo />'));
      PR_innerHtmlWorks = !/</.test(testNode.innerHTML);
    }

    if (PR_innerHtmlWorks) {
      var content = node.innerHTML;
      // XMP tags contain unescaped entities so require special handling.
      if (isRawContent(node)) {
        content = textToHtml(content);
      }
      return content;
    }

    var out = [];
    for (var child = node.firstChild; child; child = child.nextSibling) {
      normalizedHtml(child, out);
    }
    return out.join('');
  }

  /** returns a function that expand tabs to spaces.  This function can be fed
    * successive chunks of text, and will maintain its own internal state to
    * keep track of how tabs are expanded.
    * @return {function (string) : string} a function that takes
    *   plain text and return the text with tabs expanded.
    * @private
    */
  function makeTabExpander(tabWidth) {
    var SPACES = '                ';
    var charInLine = 0;

    return function (plainText) {
      // walk over each character looking for tabs and newlines.
      // On tabs, expand them.  On newlines, reset charInLine.
      // Otherwise increment charInLine
      var out = null;
      var pos = 0;
      for (var i = 0, n = plainText.length; i < n; ++i) {
        var ch = plainText.charAt(i);

        switch (ch) {
          case '\t':
            if (!out) { out = []; }
            out.push(plainText.substring(pos, i));
            // calculate how much space we need in front of this part
            // nSpaces is the amount of padding -- the number of spaces needed
            // to move us to the next column, where columns occur at factors of
            // tabWidth.
            var nSpaces = tabWidth - (charInLine % tabWidth);
            charInLine += nSpaces;
            for (; nSpaces >= 0; nSpaces -= SPACES.length) {
              out.push(SPACES.substring(0, nSpaces));
            }
            pos = i + 1;
            break;
          case '\n':
            charInLine = 0;
            break;
          default:
            ++charInLine;
        }
      }
      if (!out) { return plainText; }
      out.push(plainText.substring(pos));
      return out.join('');
    };
  }

  var pr_chunkPattern = new RegExp(
      '[^<]+'  // A run of characters other than '<'
      + '|<\!--[\\s\\S]*?--\>'  // an HTML comment
      + '|<!\\[CDATA\\[[\\s\\S]*?\\]\\]>'  // a CDATA section
      + '|</?[a-zA-Z][^>]*>'  // a probable tag that should not be highlighted
      + '|<',  // A '<' that does not begin a larger chunk
      'g');
  var pr_commentPrefix = /^<\!--/;
  var pr_cdataPrefix = /^<\[CDATA\[/;
  var pr_brPrefix = /^<br\b/i;
  var pr_tagNameRe = /^<(\/?)([a-zA-Z]+)/;

  /** split markup into chunks of html tags (style null) and
    * plain text (style {@link #PR_PLAIN}), converting tags which are
    * significant for tokenization (<br>) into their textual equivalent.
    *
    * @param {string} s html where whitespace is considered significant.
    * @return {Object} source code and extracted tags.
    * @private
    */
  function extractTags(s) {
    // since the pattern has the 'g' modifier and defines no capturing groups,
    // this will return a list of all chunks which we then classify and wrap as
    // PR_Tokens
    var matches = s.match(pr_chunkPattern);
    var sourceBuf = [];
    var sourceBufLen = 0;
    var extractedTags = [];
    if (matches) {
      for (var i = 0, n = matches.length; i < n; ++i) {
        var match = matches[i];
        if (match.length > 1 && match.charAt(0) === '<') {
          if (pr_commentPrefix.test(match)) { continue; }
          if (pr_cdataPrefix.test(match)) {
            // strip CDATA prefix and suffix.  Don't unescape since it's CDATA
            sourceBuf.push(match.substring(9, match.length - 3));
            sourceBufLen += match.length - 12;
          } else if (pr_brPrefix.test(match)) {
            // <br> tags are lexically significant so convert them to text.
            // This is undone later.
            sourceBuf.push('\n');
            ++sourceBufLen;
          } else {
            if (match.indexOf(PR_NOCODE) >= 0 && isNoCodeTag(match)) {
              // A <span class="nocode"> will start a section that should be
              // ignored.  Continue walking the list until we see a matching end
              // tag.
              var name = match.match(pr_tagNameRe)[2];
              var depth = 1;
              var j;
              end_tag_loop:
              for (j = i + 1; j < n; ++j) {
                var name2 = matches[j].match(pr_tagNameRe);
                if (name2 && name2[2] === name) {
                  if (name2[1] === '/') {
                    if (--depth === 0) { break end_tag_loop; }
                  } else {
                    ++depth;
                  }
                }
              }
              if (j < n) {
                extractedTags.push(
                    sourceBufLen, matches.slice(i, j + 1).join(''));
                i = j;
              } else {  // Ignore unclosed sections.
                extractedTags.push(sourceBufLen, match);
              }
            } else {
              extractedTags.push(sourceBufLen, match);
            }
          }
        } else {
          var literalText = htmlToText(match);
          sourceBuf.push(literalText);
          sourceBufLen += literalText.length;
        }
      }
    }
    return { source: sourceBuf.join(''), tags: extractedTags };
  }

  /** True if the given tag contains a class attribute with the nocode class. */
  function isNoCodeTag(tag) {
    return !!tag
        // First canonicalize the representation of attributes
        .replace(/\s(\w+)\s*=\s*(?:\"([^\"]*)\"|'([^\']*)'|(\S+))/g,
                 ' $1="$2$3$4"')
        // Then look for the attribute we want.
        .match(/[cC][lL][aA][sS][sS]=\"[^\"]*\bnocode\b/);
  }

  /**
   * Apply the given language handler to sourceCode and add the resulting
   * decorations to out.
   * @param {number} basePos the index of sourceCode within the chunk of source
   *    whose decorations are already present on out.
   */
  function appendDecorations(basePos, sourceCode, langHandler, out) {
    if (!sourceCode) { return; }
    var job = {
      source: sourceCode,
      basePos: basePos
    };
    langHandler(job);
    out.push.apply(out, job.decorations);
  }

  /** Given triples of [style, pattern, context] returns a lexing function,
    * The lexing function interprets the patterns to find token boundaries and
    * returns a decoration list of the form
    * [index_0, style_0, index_1, style_1, ..., index_n, style_n]
    * where index_n is an index into the sourceCode, and style_n is a style
    * constant like PR_PLAIN.  index_n-1 <= index_n, and style_n-1 applies to
    * all characters in sourceCode[index_n-1:index_n].
    *
    * The stylePatterns is a list whose elements have the form
    * [style : string, pattern : RegExp, DEPRECATED, shortcut : string].
    *
    * Style is a style constant like PR_PLAIN, or can be a string of the
    * form 'lang-FOO', where FOO is a language extension describing the
    * language of the portion of the token in $1 after pattern executes.
    * E.g., if style is 'lang-lisp', and group 1 contains the text
    * '(hello (world))', then that portion of the token will be passed to the
    * registered lisp handler for formatting.
    * The text before and after group 1 will be restyled using this decorator
    * so decorators should take care that this doesn't result in infinite
    * recursion.  For example, the HTML lexer rule for SCRIPT elements looks
    * something like ['lang-js', /<[s]cript>(.+?)<\/script>/].  This may match
    * '<script>foo()<\/script>', which would cause the current decorator to
    * be called with '<script>' which would not match the same rule since
    * group 1 must not be empty, so it would be instead styled as PR_TAG by
    * the generic tag rule.  The handler registered for the 'js' extension would
    * then be called with 'foo()', and finally, the current decorator would
    * be called with '<\/script>' which would not match the original rule and
    * so the generic tag rule would identify it as a tag.
    *
    * Pattern must only match prefixes, and if it matches a prefix, then that
    * match is considered a token with the same style.
    *
    * Context is applied to the last non-whitespace, non-comment token
    * recognized.
    *
    * Shortcut is an optional string of characters, any of which, if the first
    * character, gurantee that this pattern and only this pattern matches.
    *
    * @param {Array} shortcutStylePatterns patterns that always start with
    *   a known character.  Must have a shortcut string.
    * @param {Array} fallthroughStylePatterns patterns that will be tried in
    *   order if the shortcut ones fail.  May have shortcuts.
    *
    * @return {function (Object)} a
    *   function that takes source code and returns a list of decorations.
    */
  function createSimpleLexer(shortcutStylePatterns, fallthroughStylePatterns) {
    var shortcuts = {};
    var tokenizer;
    (function () {
      var allPatterns = shortcutStylePatterns.concat(fallthroughStylePatterns);
      var allRegexs = [];
      var regexKeys = {};
      for (var i = 0, n = allPatterns.length; i < n; ++i) {
        var patternParts = allPatterns[i];
        var shortcutChars = patternParts[3];
        if (shortcutChars) {
          for (var c = shortcutChars.length; --c >= 0;) {
            shortcuts[shortcutChars.charAt(c)] = patternParts;
          }
        }
        var regex = patternParts[1];
        var k = '' + regex;
        if (!regexKeys.hasOwnProperty(k)) {
          allRegexs.push(regex);
          regexKeys[k] = null;
        }
      }
      allRegexs.push(/[\0-\uffff]/);
      tokenizer = combinePrefixPatterns(allRegexs);
    })();

    var nPatterns = fallthroughStylePatterns.length;
    var notWs = /\S/;

    /**
     * Lexes job.source and produces an output array job.decorations of style
     * classes preceded by the position at which they start in job.source in
     * order.
     *
     * @param {Object} job an object like {@code
     *    source: {string} sourceText plain text,
     *    basePos: {int} position of job.source in the larger chunk of
     *        sourceCode.
     * }
     */
    var decorate = function (job) {
      var sourceCode = job.source, basePos = job.basePos;
      /** Even entries are positions in source in ascending order.  Odd enties
        * are style markers (e.g., PR_COMMENT) that run from that position until
        * the end.
        * @type {Array.<number|string>}
        */
      var decorations = [basePos, PR_PLAIN];
      var pos = 0;  // index into sourceCode
      var tokens = sourceCode.match(tokenizer) || [];
      var styleCache = {};

      for (var ti = 0, nTokens = tokens.length; ti < nTokens; ++ti) {
        var token = tokens[ti];
        var style = styleCache[token];
        var match;

        var isEmbedded;
        if (typeof style === 'string') {
          isEmbedded = false;
        } else {
          var patternParts = shortcuts[token.charAt(0)];
          if (patternParts) {
            match = token.match(patternParts[1]);
            style = patternParts[0];
          } else {
            for (var i = 0; i < nPatterns; ++i) {
              patternParts = fallthroughStylePatterns[i];
              match = token.match(patternParts[1]);
              if (match) {
                style = patternParts[0];
                break;
              }
            }

            if (!match) {  // make sure that we make progress
              style = PR_PLAIN;
            }
          }

          isEmbedded = style.length >= 5 && 'lang-' === style.substring(0, 5);
          if (isEmbedded && !(match && match[1])) {
            isEmbedded = false;
            style = PR_SOURCE;
          }

          if (!isEmbedded) { styleCache[token] = style; }
        }

        var tokenStart = pos;
        pos += token.length;

        if (!isEmbedded) {
          decorations.push(basePos + tokenStart, style);
        } else {  // Treat group 1 as an embedded block of source code.
          var embeddedSource = match[1];
          var embeddedSourceStart = token.indexOf(embeddedSource);
          var embeddedSourceEnd = embeddedSourceStart + embeddedSource.length;
          var lang = style.substring(5);
          var size = decorations.length - 10;
          // Decorate the left of the embedded source
          appendDecorations(
              basePos + tokenStart,
              token.substring(0, embeddedSourceStart),
              decorate, decorations);
          // Decorate the embedded source
          appendDecorations(
              basePos + tokenStart + embeddedSourceStart,
              embeddedSource,
              langHandlerForExtension(lang, embeddedSource),
              decorations);
          // Decorate the right of the embedded section
          appendDecorations(
              basePos + tokenStart + embeddedSourceEnd,
              token.substring(embeddedSourceEnd),
              decorate, decorations);
        }
      }
      job.decorations = decorations;
    };
    return decorate;
  }

  /** returns a function that produces a list of decorations from source text.
    *
    * This code treats ", ', and ` as string delimiters, and \ as a string
    * escape.  It does not recognize perl's qq() style strings.
    * It has no special handling for double delimiter escapes as in basic, or
    * the tripled delimiters used in python, but should work on those regardless
    * although in those cases a single string literal may be broken up into
    * multiple adjacent string literals.
    *
    * It recognizes C, C++, and shell style comments.
    *
    * @param {Object} options a set of optional parameters.
    * @return {function (Object)} a function that examines the source code
    *     in the input job and builds the decoration list.
    */
  function sourceDecorator(options) {
    var shortcutStylePatterns = [], fallthroughStylePatterns = [];
    if (options['tripleQuotedStrings']) {
      // '''multi-line-string''', 'single-line-string', and double-quoted
      shortcutStylePatterns.push(
          [PR_STRING,  /^(?:\'\'\'(?:[^\'\\]|\\[\s\S]|\'{1,2}(?=[^\']))*(?:\'\'\'|$)|\"\"\"(?:[^\"\\]|\\[\s\S]|\"{1,2}(?=[^\"]))*(?:\"\"\"|$)|\'(?:[^\\\']|\\[\s\S])*(?:\'|$)|\"(?:[^\\\"]|\\[\s\S])*(?:\"|$))/,
           null, '\'"']);
    } else if (options['multiLineStrings']) {
      // 'multi-line-string', "multi-line-string"
      shortcutStylePatterns.push(
          [PR_STRING,  /^(?:\'(?:[^\\\']|\\[\s\S])*(?:\'|$)|\"(?:[^\\\"]|\\[\s\S])*(?:\"|$)|\`(?:[^\\\`]|\\[\s\S])*(?:\`|$))/,
           null, '\'"`']);
    } else {
      // 'single-line-string', "single-line-string"
      shortcutStylePatterns.push(
          [PR_STRING,
           /^(?:\'(?:[^\\\'\r\n]|\\.)*(?:\'|$)|\"(?:[^\\\"\r\n]|\\.)*(?:\"|$))/,
           null, '"\'']);
    }
    if (options['hashComments']) {
      if (options['cStyleComments']) {
        // Stop C preprocessor declarations at an unclosed open comment
        shortcutStylePatterns.push(
            [PR_COMMENT, /^#(?:[^\r\n\/]|\/(?!\*)|\/\*[^\r\n]*?\*\/)*/,
             null, '#']);
      } else {
        shortcutStylePatterns.push([PR_COMMENT, /^#[^\r\n]*/, null, '#']);
      }
    }
    if (options['cStyleComments']) {
      fallthroughStylePatterns.push([PR_COMMENT, /^\/\/[^\r\n]*/, null]);
      fallthroughStylePatterns.push(
          [PR_COMMENT, /^\/\*[\s\S]*?(?:\*\/|$)/, null]);
    }
    if (options['regexLiterals']) {
      var REGEX_LITERAL = (
          // A regular expression literal starts with a slash that is
          // not followed by * or / so that it is not confused with
          // comments.
          '/(?=[^/*])'
          // and then contains any number of raw characters,
          + '(?:[^/\\x5B\\x5C]'
          // escape sequences (\x5C),
          +    '|\\x5C[\\s\\S]'
          // or non-nesting character sets (\x5B\x5D);
          +    '|\\x5B(?:[^\\x5C\\x5D]|\\x5C[\\s\\S])*(?:\\x5D|$))+'
          // finally closed by a /.
          + '/');
      fallthroughStylePatterns.push(
          ['lang-regex',
           new RegExp('^' + REGEXP_PRECEDER_PATTERN + '(' + REGEX_LITERAL + ')')
           ]);
    }

    var keywords = options['keywords'].replace(/^\s+|\s+$/g, '');
    if (keywords.length) {
      fallthroughStylePatterns.push(
          [PR_KEYWORD,
           new RegExp('^(?:' + keywords.replace(/\s+/g, '|') + ')\\b'), null]);
    }

    shortcutStylePatterns.push([PR_PLAIN,       /^\s+/, null, ' \r\n\t\xA0']);
    fallthroughStylePatterns.push(
        // TODO(mikesamuel): recognize non-latin letters and numerals in idents
        [PR_LITERAL,     /^@[a-z_$][a-z_$@0-9]*/i, null, '@'],
        [PR_TYPE,        /^@?[A-Z]+[a-z][A-Za-z_$@0-9]*/, null],
        [PR_PLAIN,       /^[a-z_$][a-z_$@0-9]*/i, null],
        [PR_LITERAL,
         new RegExp(
             '^(?:'
             // A hex number
             + '0x[a-f0-9]+'
             // or an octal or decimal number,
             + '|(?:\\d(?:_\\d+)*\\d*(?:\\.\\d*)?|\\.\\d\\+)'
             // possibly in scientific notation
             + '(?:e[+\\-]?\\d+)?'
             + ')'
             // with an optional modifier like UL for unsigned long
             + '[a-z]*', 'i'),
         null, '0123456789'],
        [PR_PUNCTUATION, /^.[^\s\w\.$@\'\"\`\/\#]*/, null]);

    return createSimpleLexer(shortcutStylePatterns, fallthroughStylePatterns);
  }

  var decorateSource = sourceDecorator({
        'keywords': ALL_KEYWORDS,
        'hashComments': true,
        'cStyleComments': true,
        'multiLineStrings': true,
        'regexLiterals': true
      });

  /** Breaks {@code job.source} around style boundaries in
    * {@code job.decorations} while re-interleaving {@code job.extractedTags},
    * and leaves the result in {@code job.prettyPrintedHtml}.
    * @param {Object} job like {
    *    source: {string} source as plain text,
    *    extractedTags: {Array.<number|string>} extractedTags chunks of raw
    *                   html preceded by their position in {@code job.source}
    *                   in order
    *    decorations: {Array.<number|string} an array of style classes preceded
    *                 by the position at which they start in job.source in order
    * }
    * @private
    */
  function recombineTagsAndDecorations(job) {
    var sourceText = job.source;
    var extractedTags = job.extractedTags;
    var decorations = job.decorations;

    var html = [];
    // index past the last char in sourceText written to html
    var outputIdx = 0;

    var openDecoration = null;
    var currentDecoration = null;
    var tagPos = 0;  // index into extractedTags
    var decPos = 0;  // index into decorations
    var tabExpander = makeTabExpander(window['PR_TAB_WIDTH']);

    var adjacentSpaceRe = /([\r\n ]) /g;
    var startOrSpaceRe = /(^| ) /gm;
    var newlineRe = /\r\n?|\n/g;
    var trailingSpaceRe = /[ \r\n]$/;
    var lastWasSpace = true;  // the last text chunk emitted ended with a space.

    // A helper function that is responsible for opening sections of decoration
    // and outputing properly escaped chunks of source
    function emitTextUpTo(sourceIdx) {
      if (sourceIdx > outputIdx) {
        if (openDecoration && openDecoration !== currentDecoration) {
          // Close the current decoration
          html.push('</span>');
          openDecoration = null;
        }
        if (!openDecoration && currentDecoration) {
          openDecoration = currentDecoration;
          html.push('<span class="', openDecoration, '">');
        }
        // This interacts badly with some wikis which introduces paragraph tags
        // into pre blocks for some strange reason.
        // It's necessary for IE though which seems to lose the preformattedness
        // of <pre> tags when their innerHTML is assigned.
        // http://stud3.tuwien.ac.at/~e0226430/innerHtmlQuirk.html
        // and it serves to undo the conversion of <br>s to newlines done in
        // chunkify.
        var htmlChunk = textToHtml(
            tabExpander(sourceText.substring(outputIdx, sourceIdx)))
            .replace(lastWasSpace
                     ? startOrSpaceRe
                     : adjacentSpaceRe, '$1&nbsp;');
        // Keep track of whether we need to escape space at the beginning of the
        // next chunk.
        lastWasSpace = trailingSpaceRe.test(htmlChunk);
        // IE collapses multiple adjacient <br>s into 1 line break.
        // Prefix every <br> with '&nbsp;' can prevent such IE's behavior.
        var lineBreakHtml = window['_pr_isIE6']() ? '&nbsp;<br />' : '<br />';
        html.push(htmlChunk.replace(newlineRe, lineBreakHtml));
        outputIdx = sourceIdx;
      }
    }

    while (true) {
      // Determine if we're going to consume a tag this time around.  Otherwise
      // we consume a decoration or exit.
      var outputTag;
      if (tagPos < extractedTags.length) {
        if (decPos < decorations.length) {
          // Pick one giving preference to extractedTags since we shouldn't open
          // a new style that we're going to have to immediately close in order
          // to output a tag.
          outputTag = extractedTags[tagPos] <= decorations[decPos];
        } else {
          outputTag = true;
        }
      } else {
        outputTag = false;
      }
      // Consume either a decoration or a tag or exit.
      if (outputTag) {
        emitTextUpTo(extractedTags[tagPos]);
        if (openDecoration) {
          // Close the current decoration
          html.push('</span>');
          openDecoration = null;
        }
        html.push(extractedTags[tagPos + 1]);
        tagPos += 2;
      } else if (decPos < decorations.length) {
        emitTextUpTo(decorations[decPos]);
        currentDecoration = decorations[decPos + 1];
        decPos += 2;
      } else {
        break;
      }
    }
    emitTextUpTo(sourceText.length);
    if (openDecoration) {
      html.push('</span>');
    }
    job.prettyPrintedHtml = html.join('');
  }

  /** Maps language-specific file extensions to handlers. */
  var langHandlerRegistry = {};
  /** Register a language handler for the given file extensions.
    * @param {function (Object)} handler a function from source code to a list
    *      of decorations.  Takes a single argument job which describes the
    *      state of the computation.   The single parameter has the form
    *      {@code {
    *        source: {string} as plain text.
    *        decorations: {Array.<number|string>} an array of style classes
    *                     preceded by the position at which they start in
    *                     job.source in order.
    *                     The language handler should assigned this field.
    *        basePos: {int} the position of source in the larger source chunk.
    *                 All positions in the output decorations array are relative
    *                 to the larger source chunk.
    *      } }
    * @param {Array.<string>} fileExtensions
    */
  function registerLangHandler(handler, fileExtensions) {
    for (var i = fileExtensions.length; --i >= 0;) {
      var ext = fileExtensions[i];
      if (!langHandlerRegistry.hasOwnProperty(ext)) {
        langHandlerRegistry[ext] = handler;
      } else if ('console' in window) {
        console.warn('cannot override language handler %s', ext);
      }
    }
  }
  function langHandlerForExtension(extension, source) {
    if (!(extension && langHandlerRegistry.hasOwnProperty(extension))) {
      // Treat it as markup if the first non whitespace character is a < and
      // the last non-whitespace character is a >.
      extension = /^\s*</.test(source)
          ? 'default-markup'
          : 'default-code';
    }
    return langHandlerRegistry[extension];
  }
  registerLangHandler(decorateSource, ['default-code']);
  registerLangHandler(
      createSimpleLexer(
          [],
          [
           [PR_PLAIN,       /^[^<?]+/],
           [PR_DECLARATION, /^<!\w[^>]*(?:>|$)/],
           [PR_COMMENT,     /^<\!--[\s\S]*?(?:-\->|$)/],
           // Unescaped content in an unknown language
           ['lang-',        /^<\?([\s\S]+?)(?:\?>|$)/],
           ['lang-',        /^<%([\s\S]+?)(?:%>|$)/],
           [PR_PUNCTUATION, /^(?:<[%?]|[%?]>)/],
           ['lang-',        /^<xmp\b[^>]*>([\s\S]+?)<\/xmp\b[^>]*>/i],
           // Unescaped content in javascript.  (Or possibly vbscript).
           ['lang-js',      /^<script\b[^>]*>([\s\S]+?)<\/script\b[^>]*>/i],
           // Contains unescaped stylesheet content
           ['lang-css',     /^<style\b[^>]*>([\s\S]+?)<\/style\b[^>]*>/i],
           ['lang-in.tag',  /^(<\/?[a-z][^<>]*>)/i]
          ]),
      ['default-markup', 'htm', 'html', 'mxml', 'xhtml', 'xml', 'xsl']);
  registerLangHandler(
      createSimpleLexer(
          [
           [PR_PLAIN,        /^[\s]+/, null, ' \t\r\n'],
           [PR_ATTRIB_VALUE, /^(?:\"[^\"]*\"?|\'[^\']*\'?)/, null, '\"\'']
           ],
          [
           [PR_TAG,          /^^<\/?[a-z](?:[\w:-]*\w)?|\/?>$/],
           [PR_ATTRIB_NAME,  /^(?!style\b|on)[a-z](?:[\w:-]*\w)?/],
           ['lang-uq.val',   /^=\s*([^>\'\"\s]*(?:[^>\'\"\s\/]|\/(?=\s)))/],
           [PR_PUNCTUATION,  /^[=<>\/]+/],
           ['lang-js',       /^on\w+\s*=\s*\"([^\"]+)\"/i],
           ['lang-js',       /^on\w+\s*=\s*\'([^\']+)\'/i],
           ['lang-js',       /^on\w+\s*=\s*([^\"\'>\s]+)/i],
           ['lang-css',      /^sty\w+\s*=\s*\"([^\"]+)\"/i],
           ['lang-css',      /^sty\w+\s*=\s*\'([^\']+)\'/i],
           ['lang-css',      /^sty\w+\s*=\s*([^\"\'>\s]+)/i]
           ]),
      ['in.tag']);
  registerLangHandler(
      createSimpleLexer([], [[PR_ATTRIB_VALUE, /^[\s\S]+/]]), ['uq.val']);
  registerLangHandler(sourceDecorator({
          'keywords': CPP_KEYWORDS,
          'hashComments': true,
          'cStyleComments': true
        }), ['c', 'cc', 'cpp', 'cxx', 'cyc', 'm']);
  registerLangHandler(sourceDecorator({
          'keywords': 'null true false'
        }), ['json']);
  registerLangHandler(sourceDecorator({
          'keywords': CSHARP_KEYWORDS,
          'hashComments': true,
          'cStyleComments': true
        }), ['cs']);
  registerLangHandler(sourceDecorator({
          'keywords': JAVA_KEYWORDS,
          'cStyleComments': true
        }), ['java']);
  registerLangHandler(sourceDecorator({
          'keywords': SH_KEYWORDS,
          'hashComments': true,
          'multiLineStrings': true
        }), ['bsh', 'csh', 'sh']);
  registerLangHandler(sourceDecorator({
          'keywords': PYTHON_KEYWORDS,
          'hashComments': true,
          'multiLineStrings': true,
          'tripleQuotedStrings': true
        }), ['cv', 'py']);
  registerLangHandler(sourceDecorator({
          'keywords': PERL_KEYWORDS,
          'hashComments': true,
          'multiLineStrings': true,
          'regexLiterals': true
        }), ['perl', 'pl', 'pm']);
  registerLangHandler(sourceDecorator({
          'keywords': RUBY_KEYWORDS,
          'hashComments': true,
          'multiLineStrings': true,
          'regexLiterals': true
        }), ['rb']);
  registerLangHandler(sourceDecorator({
          'keywords': JSCRIPT_KEYWORDS,
          'cStyleComments': true,
          'regexLiterals': true
        }), ['js']);
  registerLangHandler(
      createSimpleLexer([], [[PR_STRING, /^[\s\S]+/]]), ['regex']);

  function applyDecorator(job) {
    var sourceCodeHtml = job.sourceCodeHtml;
    var opt_langExtension = job.langExtension;

    // Prepopulate output in case processing fails with an exception.
    job.prettyPrintedHtml = sourceCodeHtml;

    try {
      // Extract tags, and convert the source code to plain text.
      var sourceAndExtractedTags = extractTags(sourceCodeHtml);
      /** Plain text. @type {string} */
      var source = sourceAndExtractedTags.source;
      job.source = source;
      job.basePos = 0;

      /** Even entries are positions in source in ascending order.  Odd entries
        * are tags that were extracted at that position.
        * @type {Array.<number|string>}
        */
      job.extractedTags = sourceAndExtractedTags.tags;

      // Apply the appropriate language handler
      langHandlerForExtension(opt_langExtension, source)(job);
      // Integrate the decorations and tags back into the source code to produce
      // a decorated html string which is left in job.prettyPrintedHtml.
      recombineTagsAndDecorations(job);
    } catch (e) {
      if ('console' in window) {
        console.log(e);
        console.trace();
      }
    }
  }

  function prettyPrintOne(sourceCodeHtml, opt_langExtension) {
    var job = {
      sourceCodeHtml: sourceCodeHtml,
      langExtension: opt_langExtension
    };
    applyDecorator(job);
    return job.prettyPrintedHtml;
  }

  function prettyPrint(opt_whenDone) {
    var isIE6 = window['_pr_isIE6']();

    // fetch a list of nodes to rewrite
    var codeSegments = [
        document.getElementsByTagName('pre'),
        document.getElementsByTagName('code'),
        document.getElementsByTagName('xmp') ];
    var elements = [];
    for (var i = 0; i < codeSegments.length; ++i) {
      for (var j = 0, n = codeSegments[i].length; j < n; ++j) {
        elements.push(codeSegments[i][j]);
      }
    }
    codeSegments = null;

    var clock = Date;
    if (!clock['now']) {
      clock = { 'now': function () { return (new Date).getTime(); } };
    }

    // The loop is broken into a series of continuations to make sure that we
    // don't make the browser unresponsive when rewriting a large page.
    var k = 0;
    var prettyPrintingJob;

    function doWork() {
      var endTime = (window['PR_SHOULD_USE_CONTINUATION'] ?
                     clock.now() + 250 /* ms */ :
                     Infinity);
      for (; k < elements.length && clock.now() < endTime; k++) {
        var cs = elements[k];
        if (cs.className && cs.className.indexOf('prettyprint') >= 0) {
          // If the classes includes a language extensions, use it.
          // Language extensions can be specified like
          //     <pre class="prettyprint lang-cpp">
          // the language extension "cpp" is used to find a language handler as
          // passed to PR_registerLangHandler.
          var langExtension = cs.className.match(/\blang-(\w+)\b/);
          if (langExtension) { langExtension = langExtension[1]; }

          // make sure this is not nested in an already prettified element
          var nested = false;
          for (var p = cs.parentNode; p; p = p.parentNode) {
            if ((p.tagName === 'pre' || p.tagName === 'code' ||
                 p.tagName === 'xmp') &&
                p.className && p.className.indexOf('prettyprint') >= 0) {
              nested = true;
              break;
            }
          }
          if (!nested) {
            // fetch the content as a snippet of properly escaped HTML.
            // Firefox adds newlines at the end.
            var content = getInnerHtml(cs);
            content = content.replace(/(?:\r\n?|\n)$/, '');

            // do the pretty printing
            prettyPrintingJob = {
              sourceCodeHtml: content,
              langExtension: langExtension,
              sourceNode: cs
            };
            applyDecorator(prettyPrintingJob);
            replaceWithPrettyPrintedHtml();
          }
        }
      }
      if (k < elements.length) {
        // finish up in a continuation
        setTimeout(doWork, 250);
      } else if (opt_whenDone) {
        opt_whenDone();
      }
    }

    function replaceWithPrettyPrintedHtml() {
      var newContent = prettyPrintingJob.prettyPrintedHtml;
      if (!newContent) { return; }
      var cs = prettyPrintingJob.sourceNode;

      // push the prettified html back into the tag.
      if (!isRawContent(cs)) {
        // just replace the old html with the new
        cs.innerHTML = newContent;
      } else {
        // we need to change the tag to a <pre> since <xmp>s do not allow
        // embedded tags such as the span tags used to attach styles to
        // sections of source code.
        var pre = document.createElement('PRE');
        for (var i = 0; i < cs.attributes.length; ++i) {
          var a = cs.attributes[i];
          if (a.specified) {
            var aname = a.name.toLowerCase();
            if (aname === 'class') {
              pre.className = a.value;  // For IE 6
            } else {
              pre.setAttribute(a.name, a.value);
            }
          }
        }
        pre.innerHTML = newContent;

        // remove the old
        cs.parentNode.replaceChild(pre, cs);
        cs = pre;
      }

      // Replace <br>s with line-feeds so that copying and pasting works
      // on IE 6.
      // Doing this on other browsers breaks lots of stuff since \r\n is
      // treated as two newlines on Firefox, and doing this also slows
      // down rendering.
      if (isIE6 && cs.tagName === 'PRE') {
        var lineBreaks = cs.getElementsByTagName('br');
        for (var j = lineBreaks.length; --j >= 0;) {
          var lineBreak = lineBreaks[j];
          lineBreak.parentNode.replaceChild(
              document.createTextNode('\r'), lineBreak);
        }
      }
    }

    doWork();
  }

  window['PR_normalizedHtml'] = normalizedHtml;
  window['prettyPrintOne'] = prettyPrintOne;
  window['prettyPrint'] = prettyPrint;
  window['PR'] = {
        'combinePrefixPatterns': combinePrefixPatterns,
        'createSimpleLexer': createSimpleLexer,
        'registerLangHandler': registerLangHandler,
        'sourceDecorator': sourceDecorator,
        'PR_ATTRIB_NAME': PR_ATTRIB_NAME,
        'PR_ATTRIB_VALUE': PR_ATTRIB_VALUE,
        'PR_COMMENT': PR_COMMENT,
        'PR_DECLARATION': PR_DECLARATION,
        'PR_KEYWORD': PR_KEYWORD,
        'PR_LITERAL': PR_LITERAL,
        'PR_NOCODE': PR_NOCODE,
        'PR_PLAIN': PR_PLAIN,
        'PR_PUNCTUATION': PR_PUNCTUATION,
        'PR_SOURCE': PR_SOURCE,
        'PR_STRING': PR_STRING,
        'PR_TAG': PR_TAG,
        'PR_TYPE': PR_TYPE
      };
})();
