Note: 500k iterations, results will vary by browser/CPU.
UUID GENERATOR ANDROID
Not really, but it's easy if you follow along.īut first, my results, compared to broofa, guid (the accepted answer), and the non-rfc-compliant generateQuickGuid: Desktop Android Indeed, joelpt even decided to toss out an RFC for generic GUID speed with generateQuickGUID.īut, can we get speed and RFC compliance? I say, YES! Can we maintain readability? Well.
![uuid generator uuid generator](https://a.fsdn.com/con/app/proj/uuidgenerator/screenshots/192327.jpg)
Awesome!īut if you're looking at that regular expression, those many replace() callbacks, toString()'s and Math.random() function calls (where he's only using four bits of the result and wasting the rest), you may start to wonder about performance. RFC4122 compliant, somewhat readable, and compact. Thus, for variant 1 (that is, most UUIDs) a random version-4 UUID will have 6 predetermined variant and version bits, leaving 122 bits for the randomly generated part, for a total of 2^122, or 5.3×10^36 (5.3 undecillion) possible version-4 variant-1 UUIDs.Broofa's answer is pretty slick, indeed - impressively clever, really. As in other UUIDs, 4 bits are used to indicate version 4, and 2 or 3 bits to indicate the variant (102 or 1102 for variants 1 and 2 respectively). Version 4 (random) A version 4 UUID is randomly generated.RFC 4122 recommends version 5 (SHA-1) over version 3 (MD5) and counsels against use of UUIDs of either version as security credentials. The specification provides UUIDs to represent the namespaces for URLs, fully qualified domain names, object identifiers, and X.500 distinguished names but any desired UUID may be used as a namespace designator. The namespace identifier is itself a UUID. Version 3 uses MD5 as the hashing algorithm, and version 5 uses SHA-1. Versions 3 and 5 (namespace name-based) Version-3 and version-5 UUIDs are generated by hashing a namespace identifier and name.On non-POSIX systems, all local domain numbers are site-defined. On POSIX systems, local-domain numbers 0 and 1 are for user ids (UIDs) and group ids (GIDs) respectively, and other local-domain numbers are site-defined.
UUID GENERATOR MAC
UUID GENERATOR REGISTRATION
Their uniqueness does not depend on a central registration authority or coordination between the parties generating them, unlike most other numbering schemes. When generated according to the standard methods, UUIDs are for practical purposes unique. The term globally unique identifier (GUID) is also used. A universally unique identifier (UUID) is a 128-bit number used to identify information in computer systems.