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- // uuid.js
- //
- // Copyright (c) 2010-2012 Robert Kieffer
- // MIT License - http://opensource.org/licenses/mit-license.php
- // Unique ID creation requires a high quality random # generator. We feature
- // detect to determine the best RNG source, normalizing to a function that
- // returns 128-bits of randomness, since that's what's usually required
- var _rng = require('./rng');
- // Buffer class to use,
- // we can't use `Buffer || Array` otherwise Buffer would be
- // shimmed by browserify and added to the browser build
- var BufferClass = require('./buffer');
- // 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(oct) {
- if (ii < 16) { // Don't overflow!
- buf[i + ii++] = _hexToByte[oct];
- }
- });
- // 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 !== undefined ? 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 !== 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`
- 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;
- module.exports = uuid;
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