Source

uuid-v1.js

/*
 * constructed via browserfy and hand edited to declare exports
 *
 *    /usr/local/bin/browserify node-uuid/v1.js -o v1-uuid.js
 */

var byteToHex = [];
for (var i = 0; i < 256; ++i) {
  byteToHex[i] = (i + 0x100).toString(16).substr(1);
}

/**
 * Convert array of 16 byte values to UUID string format of the form:
 * XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX
 */
export function bytesToUuid(buf, offset) {
  var i = offset || 0;
  var bth = byteToHex;
  // join used to fix memory issue caused by concatenation: https://bugs.chromium.org/p/v8/issues/detail?id=3175#c4
  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++]]]).join('');
}


// Unique ID creation requires a high quality random # generator.  In the
// browser this is a little complicated due to unknown quality of Math.random()
// and inconsistent support for the `crypto` API.  We do the best we can via
// feature-detection

// getRandomValues needs to be invoked in a context where "this" is a Crypto
// implementation. Also, find the complete implementation of crypto on IE11.
var getRandomValues = (typeof(crypto) != 'undefined' && crypto.getRandomValues && crypto.getRandomValues.bind(crypto)) ||
                      (typeof(msCrypto) != 'undefined' && typeof window.msCrypto.getRandomValues == 'function' && msCrypto.getRandomValues.bind(msCrypto));
export var rng = null;
if (getRandomValues) {
  // WHATWG crypto RNG - http://wiki.whatwg.org/wiki/Crypto
  var rnds8 = new Uint8Array(16); // eslint-disable-line no-undef

   rng = function whatwgRNG() {
    getRandomValues(rnds8);
    return rnds8;
  };
} else {
  // Math.random()-based (RNG)
  //
  // If all else fails, use Math.random().  It's fast, but is of unspecified
  // quality.
  var rnds = new Array(16);

  rng = function mathRNG() {
    for (var i = 0, r; i < 16; i++) {
      if ((i & 0x03) === 0) r = Math.random() * 0x100000000;
      rnds[i] = r >>> ((i & 0x03) << 3) & 0xff;
    }

    return rnds;
  };
}

// **`v1()` - Generate time-based UUID**
//
// Inspired by https://github.com/LiosK/UUID.js
// and http://docs.python.org/library/uuid.html

var _nodeId;
var _clockseq;

// Previous uuid creation time
var _lastMSecs = 0;
var _lastNSecs = 0;

// See https://github.com/broofa/node-uuid for API details
/**
 Compute a v1 UUID
 Given a buffer use that to construct the value and return it.
 Absent a buffer, create a temporarx for construction, but translate
 the result into hex-encoded-string and return that.
 */
export function v1(options, buf, offset) {
  var i = buf && offset || 0;
  var b = buf || [];

  options = options || {};
  var node = options.node || _nodeId;
  var clockseq = options.clockseq !== undefined ? options.clockseq : _clockseq;

  // node and clockseq need to be initialized to random values if they're not
  // specified.  We do this lazily to minimize issues related to insufficient
  // system entropy.  See #189
  if (node == null || clockseq == null) {
    var seedBytes = rng();
    if (node == null) {
      // Per 4.5, create and 48-bit node id, (47 random bits + multicast bit = 1)
      node = _nodeId = [
        seedBytes[0] | 0x01,
        seedBytes[1], seedBytes[2], seedBytes[3], seedBytes[4], seedBytes[5]
      ];
    }
    if (clockseq == null) {
      // Per 4.2.2, randomize (14 bit) clockseq
      clockseq = _clockseq = (seedBytes[6] << 8 | seedBytes[7]) & 0x3fff;
    }
  }

  // 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 !== undefined ? 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 !== undefined ? 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 === undefined) {
    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 === undefined) {
    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`
  for (var n = 0; n < 6; ++n) {
    b[i + n] = node[n];
  }

  return buf ? buf : bytesToUuid(b);
}