agsamantha/node_modules/uuid/dist/v7.js
2024-10-02 15:15:21 -05:00

152 lines
No EOL
4.9 KiB
JavaScript

"use strict";
Object.defineProperty(exports, "__esModule", {
value: true
});
exports.default = void 0;
var _rng = _interopRequireDefault(require("./rng.js"));
var _stringify = require("./stringify.js");
function _interopRequireDefault(e) { return e && e.__esModule ? e : { default: e }; }
/**
* UUID V7 - Unix Epoch time-based UUID
*
* The IETF has published RFC9562, introducing 3 new UUID versions (6,7,8). This
* implementation of V7 is based on the accepted, though not yet approved,
* revisions.
*
* RFC 9562:https://www.rfc-editor.org/rfc/rfc9562.html Universally Unique
* IDentifiers (UUIDs)
*
* Sample V7 value:
* https://www.rfc-editor.org/rfc/rfc9562.html#name-example-of-a-uuidv7-value
*
* Monotonic Bit Layout: RFC rfc9562.6.2 Method 1, Dedicated Counter Bits ref:
* https://www.rfc-editor.org/rfc/rfc9562.html#section-6.2-5.1
*
* 0 1 2 3 0 1 2 3 4 5 6
* 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | unix_ts_ms |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | unix_ts_ms | ver | seq_hi |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* |var| seq_low | rand |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | rand |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*
* seq is a 31 bit serialized counter; comprised of 12 bit seq_hi and 19 bit
* seq_low, and randomly initialized upon timestamp change. 31 bit counter size
* was selected as any bitwise operations in node are done as _signed_ 32 bit
* ints. we exclude the sign bit.
*/
let _seqLow = null;
let _seqHigh = null;
let _msecs = 0;
function v7(options, buf, offset) {
options = options || {};
// initialize buffer and pointer
let i = buf && offset || 0;
const b = buf || new Uint8Array(16);
// rnds is Uint8Array(16) filled with random bytes
const rnds = options.random || (options.rng || _rng.default)();
// milliseconds since unix epoch, 1970-01-01 00:00
const msecs = options.msecs !== undefined ? options.msecs : Date.now();
// seq is user provided 31 bit counter
let seq = options.seq !== undefined ? options.seq : null;
// initialize local seq high/low parts
let seqHigh = _seqHigh;
let seqLow = _seqLow;
// check if clock has advanced and user has not provided msecs
if (msecs > _msecs && options.msecs === undefined) {
_msecs = msecs;
// unless user provided seq, reset seq parts
if (seq !== null) {
seqHigh = null;
seqLow = null;
}
}
// if we have a user provided seq
if (seq !== null) {
// trim provided seq to 31 bits of value, avoiding overflow
if (seq > 0x7fffffff) {
seq = 0x7fffffff;
}
// split provided seq into high/low parts
seqHigh = seq >>> 19 & 0xfff;
seqLow = seq & 0x7ffff;
}
// randomly initialize seq
if (seqHigh === null || seqLow === null) {
seqHigh = rnds[6] & 0x7f;
seqHigh = seqHigh << 8 | rnds[7];
seqLow = rnds[8] & 0x3f; // pad for var
seqLow = seqLow << 8 | rnds[9];
seqLow = seqLow << 5 | rnds[10] >>> 3;
}
// increment seq if within msecs window
if (msecs + 10000 > _msecs && seq === null) {
if (++seqLow > 0x7ffff) {
seqLow = 0;
if (++seqHigh > 0xfff) {
seqHigh = 0;
// increment internal _msecs. this allows us to continue incrementing
// while staying monotonic. Note, once we hit 10k milliseconds beyond system
// clock, we will reset breaking monotonicity (after (2^31)*10000 generations)
_msecs++;
}
}
} else {
// resetting; we have advanced more than
// 10k milliseconds beyond system clock
_msecs = msecs;
}
_seqHigh = seqHigh;
_seqLow = seqLow;
// [bytes 0-5] 48 bits of local timestamp
b[i++] = _msecs / 0x10000000000 & 0xff;
b[i++] = _msecs / 0x100000000 & 0xff;
b[i++] = _msecs / 0x1000000 & 0xff;
b[i++] = _msecs / 0x10000 & 0xff;
b[i++] = _msecs / 0x100 & 0xff;
b[i++] = _msecs & 0xff;
// [byte 6] - set 4 bits of version (7) with first 4 bits seq_hi
b[i++] = seqHigh >>> 4 & 0x0f | 0x70;
// [byte 7] remaining 8 bits of seq_hi
b[i++] = seqHigh & 0xff;
// [byte 8] - variant (2 bits), first 6 bits seq_low
b[i++] = seqLow >>> 13 & 0x3f | 0x80;
// [byte 9] 8 bits seq_low
b[i++] = seqLow >>> 5 & 0xff;
// [byte 10] remaining 5 bits seq_low, 3 bits random
b[i++] = seqLow << 3 & 0xff | rnds[10] & 0x07;
// [bytes 11-15] always random
b[i++] = rnds[11];
b[i++] = rnds[12];
b[i++] = rnds[13];
b[i++] = rnds[14];
b[i++] = rnds[15];
return buf || (0, _stringify.unsafeStringify)(b);
}
var _default = exports.default = v7;