190 lines
5.4 KiB
JavaScript
190 lines
5.4 KiB
JavaScript
// uuid.js
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//
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// Copyright (c) 2010-2012 Robert Kieffer
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// MIT License - http://opensource.org/licenses/mit-license.php
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// Unique ID creation requires a high quality random # generator. We feature
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// detect to determine the best RNG source, normalizing to a function that
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// returns 128-bits of randomness, since that's what's usually required
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var _rng = require('./rng');
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// Buffer class to use,
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// we can't use `Buffer || Array` otherwise Buffer would be
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// shimmed by browserify and added to the browser build
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var BufferClass = require('./buffer');
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// Maps for number <-> hex string conversion
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var _byteToHex = [];
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var _hexToByte = {};
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for (var i = 0; i < 256; i++) {
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_byteToHex[i] = (i + 0x100).toString(16).substr(1);
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_hexToByte[_byteToHex[i]] = i;
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}
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// **`parse()` - Parse a UUID into it's component bytes**
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function parse(s, buf, offset) {
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var i = (buf && offset) || 0, ii = 0;
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buf = buf || [];
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s.toLowerCase().replace(/[0-9a-f]{2}/g, function(oct) {
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if (ii < 16) { // Don't overflow!
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buf[i + ii++] = _hexToByte[oct];
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}
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});
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// Zero out remaining bytes if string was short
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while (ii < 16) {
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buf[i + ii++] = 0;
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}
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return buf;
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}
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// **`unparse()` - Convert UUID byte array (ala parse()) into a string**
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function unparse(buf, offset) {
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var i = offset || 0, bth = _byteToHex;
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return bth[buf[i++]] + bth[buf[i++]] +
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bth[buf[i++]] + bth[buf[i++]] + '-' +
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bth[buf[i++]] + bth[buf[i++]] + '-' +
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bth[buf[i++]] + bth[buf[i++]] + '-' +
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bth[buf[i++]] + bth[buf[i++]] + '-' +
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bth[buf[i++]] + bth[buf[i++]] +
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bth[buf[i++]] + bth[buf[i++]] +
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bth[buf[i++]] + bth[buf[i++]];
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}
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// **`v1()` - Generate time-based UUID**
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//
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// Inspired by https://github.com/LiosK/UUID.js
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// and http://docs.python.org/library/uuid.html
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// random #'s we need to init node and clockseq
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var _seedBytes = _rng();
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// Per 4.5, create and 48-bit node id, (47 random bits + multicast bit = 1)
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var _nodeId = [
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_seedBytes[0] | 0x01,
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_seedBytes[1], _seedBytes[2], _seedBytes[3], _seedBytes[4], _seedBytes[5]
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];
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// Per 4.2.2, randomize (14 bit) clockseq
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var _clockseq = (_seedBytes[6] << 8 | _seedBytes[7]) & 0x3fff;
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// Previous uuid creation time
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var _lastMSecs = 0, _lastNSecs = 0;
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// See https://github.com/broofa/node-uuid for API details
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function v1(options, buf, offset) {
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var i = buf && offset || 0;
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var b = buf || [];
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options = options || {};
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var clockseq = options.clockseq !== undefined ? options.clockseq : _clockseq;
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// UUID timestamps are 100 nano-second units since the Gregorian epoch,
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// (1582-10-15 00:00). JSNumbers aren't precise enough for this, so
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// time is handled internally as 'msecs' (integer milliseconds) and 'nsecs'
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// (100-nanoseconds offset from msecs) since unix epoch, 1970-01-01 00:00.
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var msecs = options.msecs !== undefined ? options.msecs : new Date().getTime();
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// Per 4.2.1.2, use count of uuid's generated during the current clock
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// cycle to simulate higher resolution clock
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var nsecs = options.nsecs !== undefined ? options.nsecs : _lastNSecs + 1;
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// Time since last uuid creation (in msecs)
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var dt = (msecs - _lastMSecs) + (nsecs - _lastNSecs)/10000;
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// Per 4.2.1.2, Bump clockseq on clock regression
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if (dt < 0 && options.clockseq === undefined) {
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clockseq = clockseq + 1 & 0x3fff;
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}
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// Reset nsecs if clock regresses (new clockseq) or we've moved onto a new
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// time interval
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if ((dt < 0 || msecs > _lastMSecs) && options.nsecs === undefined) {
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nsecs = 0;
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}
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// Per 4.2.1.2 Throw error if too many uuids are requested
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if (nsecs >= 10000) {
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throw new Error('uuid.v1(): Can\'t create more than 10M uuids/sec');
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}
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_lastMSecs = msecs;
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_lastNSecs = nsecs;
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_clockseq = clockseq;
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// Per 4.1.4 - Convert from unix epoch to Gregorian epoch
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msecs += 12219292800000;
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// `time_low`
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var tl = ((msecs & 0xfffffff) * 10000 + nsecs) % 0x100000000;
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b[i++] = tl >>> 24 & 0xff;
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b[i++] = tl >>> 16 & 0xff;
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b[i++] = tl >>> 8 & 0xff;
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b[i++] = tl & 0xff;
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// `time_mid`
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var tmh = (msecs / 0x100000000 * 10000) & 0xfffffff;
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b[i++] = tmh >>> 8 & 0xff;
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b[i++] = tmh & 0xff;
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// `time_high_and_version`
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b[i++] = tmh >>> 24 & 0xf | 0x10; // include version
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b[i++] = tmh >>> 16 & 0xff;
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// `clock_seq_hi_and_reserved` (Per 4.2.2 - include variant)
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b[i++] = clockseq >>> 8 | 0x80;
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// `clock_seq_low`
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b[i++] = clockseq & 0xff;
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// `node`
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var node = options.node || _nodeId;
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for (var n = 0; n < 6; n++) {
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b[i + n] = node[n];
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}
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return buf ? buf : unparse(b);
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}
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// **`v4()` - Generate random UUID**
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// See https://github.com/broofa/node-uuid for API details
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function v4(options, buf, offset) {
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// Deprecated - 'format' argument, as supported in v1.2
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var i = buf && offset || 0;
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if (typeof(options) == 'string') {
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buf = options == 'binary' ? new BufferClass(16) : null;
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options = null;
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}
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options = options || {};
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var rnds = options.random || (options.rng || _rng)();
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// Per 4.4, set bits for version and `clock_seq_hi_and_reserved`
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rnds[6] = (rnds[6] & 0x0f) | 0x40;
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rnds[8] = (rnds[8] & 0x3f) | 0x80;
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// Copy bytes to buffer, if provided
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if (buf) {
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for (var ii = 0; ii < 16; ii++) {
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buf[i + ii] = rnds[ii];
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}
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}
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return buf || unparse(rnds);
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}
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// Export public API
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var uuid = v4;
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uuid.v1 = v1;
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uuid.v4 = v4;
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uuid.parse = parse;
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uuid.unparse = unparse;
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uuid.BufferClass = BufferClass;
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module.exports = uuid;
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