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JavaScript

5 years ago
// 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');
// 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 Array(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;
module.exports = uuid;