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183 lines
5.2 KiB
183 lines
5.2 KiB
// 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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// 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 Array(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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module.exports = uuid;
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