text: //     node-uuid/uuid.js
  //
  //     Copyright (c) 2010 Robert Kieffer
  //     Dual licensed under the MIT and GPL licenses.
  //     Documentation and details at https://github.com/broofa/node-uuid
  (function() {
    var _global = this;
  
    // Unique ID creation requires a high quality random # generator, but
    // Math.random() does not guarantee "cryptographic quality".  So we feature
    // detect for more robust APIs, normalizing each method to return 128-bits
    // (16 bytes) of random data.
    var mathRNG, nodeRNG, whatwgRNG;
  
    // Math.random()-based RNG.  All platforms, very fast, unknown quality
    var _rndBytes = new Array(16);
    mathRNG = function() {
      var r, b = _rndBytes, i = 0;
  
      for (var i = 0, r; i < 16; i++) {
        if ((i & 0x03) == 0) r = Math.random() * 0x100000000;
        b[i] = r >>> ((i & 0x03) << 3) & 0xff;
      }
  
      return b;
    }
  
    // WHATWG crypto-based RNG - http://wiki.whatwg.org/wiki/Crypto
    // WebKit only (currently), moderately fast, high quality
    if (_global.crypto && crypto.getRandomValues) {
      var _rnds = new Uint32Array(4);
      whatwgRNG = function() {
        crypto.getRandomValues(_rnds);
  
        for (var c = 0 ; c < 16; c++) {
          _rndBytes[c] = _rnds[c >> 2] >>> ((c & 0x03) * 8) & 0xff;
        }
        return _rndBytes;
      }
    }
  
    // Node.js crypto-based RNG - http://nodejs.org/docs/v0.6.2/api/crypto.html
    // Node.js only, moderately fast, high quality
    try {
      var _rb = require('crypto').randomBytes;
      nodeRNG = _rb && function() {
        return _rb(16);
      };
    } catch (e) {}
  
    // Select RNG with best quality
    var _rng = nodeRNG || whatwgRNG || mathRNG;
  
    // Buffer class to use
    var BufferClass = typeof(Buffer) == 'function' ? Buffer : Array;
  
    // Maps for number <-> hex string conversion
    var _byteToHex = [];
    var _hexToByte = {};
    for (var i = 0; i < 256; i++) {
      _byteToHex[i] = (i + 0x100).toString(16).substr(1);
      _hexToByte[_byteToHex[i]] = i;
    }
  
    // **`parse()` - Parse a UUID into it's component bytes**
    function parse(s, buf, offset) {
      var i = (buf && offset) || 0, ii = 0;
  
      buf = buf || [];
      s.toLowerCase().replace(/[0-9a-f]{2}/g, function(byte) {
        if (ii < 16) { // Don't overflow!
          buf[i + ii++] = _hexToByte[byte];
        }
      });
  
      // Zero out remaining bytes if string was short
      while (ii < 16) {
        buf[i + ii++] = 0;
      }
  
      return buf;
    }
  
    // **`unparse()` - Convert UUID byte array (ala parse()) into a string**
    function unparse(buf, offset) {
      var i = offset || 0, bth = _byteToHex;
      return  bth[buf[i++]] + bth[buf[i++]] +
              bth[buf[i++]] + bth[buf[i++]] + '-' +
              bth[buf[i++]] + bth[buf[i++]] + '-' +
              bth[buf[i++]] + bth[buf[i++]] + '-' +
              bth[buf[i++]] + bth[buf[i++]] + '-' +
              bth[buf[i++]] + bth[buf[i++]] +
              bth[buf[i++]] + bth[buf[i++]] +
              bth[buf[i++]] + bth[buf[i++]];
    }
  
    // **`v1()` - Generate time-based UUID**
    //
    // Inspired by https://github.com/LiosK/UUID.js
    // and http://docs.python.org/library/uuid.html
  
    // random #'s we need to init node and clockseq
    var _seedBytes = _rng();
  
    // Per 4.5, create and 48-bit node id, (47 random bits + multicast bit = 1)
    var _nodeId = [
      _seedBytes[0] | 0x01,
      _seedBytes[1], _seedBytes[2], _seedBytes[3], _seedBytes[4], _seedBytes[5]
    ];
  
    // Per 4.2.2, randomize (14 bit) clockseq
    var _clockseq = (_seedBytes[6] << 8 | _seedBytes[7]) & 0x3fff;
  
    // Previous uuid creation time
    var _lastMSecs = 0, _lastNSecs = 0;
  
    // See https://github.com/broofa/node-uuid for API details
    function v1(options, buf, offset) {
      var i = buf && offset || 0;
      var b = buf || [];
  
      options = options || {};
  
      var clockseq = options.clockseq != null ? options.clockseq : _clockseq;
  
      // UUID timestamps are 100 nano-second units since the Gregorian epoch,
      // (1582-10-15 00:00).  JSNumbers aren't precise enough for this, so
      // time is handled internally as 'msecs' (integer milliseconds) and 'nsecs'
      // (100-nanoseconds offset from msecs) since unix epoch, 1970-01-01 00:00.
      var msecs = options.msecs != null ? options.msecs : new Date().getTime();
  
      // Per 4.2.1.2, use count of uuid's generated during the current clock
      // cycle to simulate higher resolution clock
      var nsecs = options.nsecs != null ? options.nsecs : _lastNSecs + 1;
  
      // Time since last uuid creation (in msecs)
      var dt = (msecs - _lastMSecs) + (nsecs - _lastNSecs)/10000;
  
      // Per 4.2.1.2, Bump clockseq on clock regression
      if (dt < 0 && options.clockseq == null) {
        clockseq = clockseq + 1 & 0x3fff;
      }
  
      // Reset nsecs if clock regresses (new clockseq) or we've moved onto a new
      // time interval
      if ((dt < 0 || msecs > _lastMSecs) && options.nsecs == null) {
        nsecs = 0;
      }
  
      // Per 4.2.1.2 Throw error if too many uuids are requested
      if (nsecs >= 10000) {
        throw new Error('uuid.v1(): Can\'t create more than 10M uuids/sec');
      }
  
      _lastMSecs = msecs;
      _lastNSecs = nsecs;
      _clockseq = clockseq;
  
      // Per 4.1.4 - Convert from unix epoch to Gregorian epoch
      msecs += 12219292800000;
  
      // `time_low`
      var tl = ((msecs & 0xfffffff) * 10000 + nsecs) % 0x100000000;
      b[i++] = tl >>> 24 & 0xff;
      b[i++] = tl >>> 16 & 0xff;
      b[i++] = tl >>> 8 & 0xff;
      b[i++] = tl & 0xff;
  
      // `time_mid`
      var tmh = (msecs / 0x100000000 * 10000) & 0xfffffff;
      b[i++] = tmh >>> 8 & 0xff;
      b[i++] = tmh & 0xff;
  
      // `time_high_and_version`
      b[i++] = tmh >>> 24 & 0xf | 0x10; // include version
      b[i++] = tmh >>> 16 & 0xff;
  
      // `clock_seq_hi_and_reserved` (Per 4.2.2 - include variant)
      b[i++] = clockseq >>> 8 | 0x80;
  
      // `clock_seq_low`
      b[i++] = clockseq & 0xff;
  
      // `node`
      var node = options.node || _nodeId;
      for (var n = 0; n < 6; n++) {
        b[i + n] = node[n];
      }
  
      return buf ? buf : unparse(b);
    }
  
    // **`v4()` - Generate random UUID**
  
    // See https://github.com/broofa/node-uuid for API details
    function v4(options, buf, offset) {
      // Deprecated - 'format' argument, as supported in v1.2
      var i = buf && offset || 0;
  
      if (typeof(options) == 'string') {
        buf = options == 'binary' ? new BufferClass(16) : null;
        options = null;
      }
      options = options || {};
  
      var rnds = options.random || (options.rng || _rng)();
  
      // Per 4.4, set bits for version and `clock_seq_hi_and_reserved`
      rnds[6] = (rnds[6] & 0x0f) | 0x40;
      rnds[8] = (rnds[8] & 0x3f) | 0x80;
  
      // Copy bytes to buffer, if provided
      if (buf) {
        for (var ii = 0; ii < 16; ii++) {
          buf[i + ii] = rnds[ii];
        }
      }
  
      return buf || unparse(rnds);
    }
  
    // Export public API
    var uuid = v4;
    uuid.v1 = v1;
    uuid.v4 = v4;
    uuid.parse = parse;
    uuid.unparse = unparse;
    uuid.BufferClass = BufferClass;
  
    // Export RNG options
    uuid.mathRNG = mathRNG;
    uuid.nodeRNG = nodeRNG;
    uuid.whatwgRNG = whatwgRNG;
  
    if (typeof(module) != 'undefined') {
      // Play nice with node.js
      module.exports = uuid;
    } else {
      // Play nice with browsers
      var _previousRoot = _global.uuid;
  
      // **`noConflict()` - (browser only) to reset global 'uuid' var**
      uuid.noConflict = function() {
        _global.uuid = _previousRoot;
        return uuid;
      }
      _global.uuid = uuid;
    }
  }());
  