1 // Unique ID creation requires a high quality random # generator. We feature
2 // detect to determine the best RNG source, normalizing to a function that
3 // returns 128-bits of randomness, since that's what's usually required
4 var rng = require('./lib/rng');
5 var bytesToUuid = require('./lib/bytesToUuid');
7 // **`v1()` - Generate time-based UUID**
9 // Inspired by https://github.com/LiosK/UUID.js
10 // and http://docs.python.org/library/uuid.html
12 // random #'s we need to init node and clockseq
13 var _seedBytes = rng();
15 // Per 4.5, create and 48-bit node id, (47 random bits + multicast bit = 1)
18 _seedBytes[1], _seedBytes[2], _seedBytes[3], _seedBytes[4], _seedBytes[5]
21 // Per 4.2.2, randomize (14 bit) clockseq
22 var _clockseq = (_seedBytes[6] << 8 | _seedBytes[7]) & 0x3fff;
24 // Previous uuid creation time
25 var _lastMSecs = 0, _lastNSecs = 0;
27 // See https://github.com/broofa/node-uuid for API details
28 function v1(options, buf, offset) {
29 var i = buf && offset || 0;
32 options = options || {};
34 var clockseq = options.clockseq !== undefined ? options.clockseq : _clockseq;
36 // UUID timestamps are 100 nano-second units since the Gregorian epoch,
37 // (1582-10-15 00:00). JSNumbers aren't precise enough for this, so
38 // time is handled internally as 'msecs' (integer milliseconds) and 'nsecs'
39 // (100-nanoseconds offset from msecs) since unix epoch, 1970-01-01 00:00.
40 var msecs = options.msecs !== undefined ? options.msecs : new Date().getTime();
42 // Per 4.2.1.2, use count of uuid's generated during the current clock
43 // cycle to simulate higher resolution clock
44 var nsecs = options.nsecs !== undefined ? options.nsecs : _lastNSecs + 1;
46 // Time since last uuid creation (in msecs)
47 var dt = (msecs - _lastMSecs) + (nsecs - _lastNSecs)/10000;
49 // Per 4.2.1.2, Bump clockseq on clock regression
50 if (dt < 0 && options.clockseq === undefined) {
51 clockseq = clockseq + 1 & 0x3fff;
54 // Reset nsecs if clock regresses (new clockseq) or we've moved onto a new
56 if ((dt < 0 || msecs > _lastMSecs) && options.nsecs === undefined) {
60 // Per 4.2.1.2 Throw error if too many uuids are requested
62 throw new Error('uuid.v1(): Can\'t create more than 10M uuids/sec');
69 // Per 4.1.4 - Convert from unix epoch to Gregorian epoch
70 msecs += 12219292800000;
73 var tl = ((msecs & 0xfffffff) * 10000 + nsecs) % 0x100000000;
74 b[i++] = tl >>> 24 & 0xff;
75 b[i++] = tl >>> 16 & 0xff;
76 b[i++] = tl >>> 8 & 0xff;
80 var tmh = (msecs / 0x100000000 * 10000) & 0xfffffff;
81 b[i++] = tmh >>> 8 & 0xff;
84 // `time_high_and_version`
85 b[i++] = tmh >>> 24 & 0xf | 0x10; // include version
86 b[i++] = tmh >>> 16 & 0xff;
88 // `clock_seq_hi_and_reserved` (Per 4.2.2 - include variant)
89 b[i++] = clockseq >>> 8 | 0x80;
92 b[i++] = clockseq & 0xff;
95 var node = options.node || _nodeId;
96 for (var n = 0; n < 6; ++n) {
100 return buf ? buf : bytesToUuid(b);