From 404aeae4545d2426c089a5f8d5e82dae56f5212b Mon Sep 17 00:00:00 2001 From: Rutger Broekhoff Date: Fri, 29 Dec 2023 21:31:53 +0100 Subject: Make Nix builds work --- vendor/github.com/rs/xid/README.md | 119 +++++++++++++++++++++++++++++++++++++ 1 file changed, 119 insertions(+) create mode 100644 vendor/github.com/rs/xid/README.md (limited to 'vendor/github.com/rs/xid/README.md') diff --git a/vendor/github.com/rs/xid/README.md b/vendor/github.com/rs/xid/README.md new file mode 100644 index 0000000..974e67d --- /dev/null +++ b/vendor/github.com/rs/xid/README.md @@ -0,0 +1,119 @@ +# Globally Unique ID Generator + +[![godoc](http://img.shields.io/badge/godoc-reference-blue.svg?style=flat)](https://godoc.org/github.com/rs/xid) [![license](http://img.shields.io/badge/license-MIT-red.svg?style=flat)](https://raw.githubusercontent.com/rs/xid/master/LICENSE) [![Build Status](https://travis-ci.org/rs/xid.svg?branch=master)](https://travis-ci.org/rs/xid) [![Coverage](http://gocover.io/_badge/github.com/rs/xid)](http://gocover.io/github.com/rs/xid) + +Package xid is a globally unique id generator library, ready to safely be used directly in your server code. + +Xid uses the Mongo Object ID algorithm to generate globally unique ids with a different serialization (base64) to make it shorter when transported as a string: +https://docs.mongodb.org/manual/reference/object-id/ + +- 4-byte value representing the seconds since the Unix epoch, +- 3-byte machine identifier, +- 2-byte process id, and +- 3-byte counter, starting with a random value. + +The binary representation of the id is compatible with Mongo 12 bytes Object IDs. +The string representation is using base32 hex (w/o padding) for better space efficiency +when stored in that form (20 bytes). The hex variant of base32 is used to retain the +sortable property of the id. + +Xid doesn't use base64 because case sensitivity and the 2 non alphanum chars may be an +issue when transported as a string between various systems. Base36 wasn't retained either +because 1/ it's not standard 2/ the resulting size is not predictable (not bit aligned) +and 3/ it would not remain sortable. To validate a base32 `xid`, expect a 20 chars long, +all lowercase sequence of `a` to `v` letters and `0` to `9` numbers (`[0-9a-v]{20}`). + +UUIDs are 16 bytes (128 bits) and 36 chars as string representation. Twitter Snowflake +ids are 8 bytes (64 bits) but require machine/data-center configuration and/or central +generator servers. xid stands in between with 12 bytes (96 bits) and a more compact +URL-safe string representation (20 chars). No configuration or central generator server +is required so it can be used directly in server's code. + +| Name | Binary Size | String Size | Features +|-------------|-------------|----------------|---------------- +| [UUID] | 16 bytes | 36 chars | configuration free, not sortable +| [shortuuid] | 16 bytes | 22 chars | configuration free, not sortable +| [Snowflake] | 8 bytes | up to 20 chars | needs machine/DC configuration, needs central server, sortable +| [MongoID] | 12 bytes | 24 chars | configuration free, sortable +| xid | 12 bytes | 20 chars | configuration free, sortable + +[UUID]: https://en.wikipedia.org/wiki/Universally_unique_identifier +[shortuuid]: https://github.com/stochastic-technologies/shortuuid +[Snowflake]: https://blog.twitter.com/2010/announcing-snowflake +[MongoID]: https://docs.mongodb.org/manual/reference/object-id/ + +Features: + +- Size: 12 bytes (96 bits), smaller than UUID, larger than snowflake +- Base32 hex encoded by default (20 chars when transported as printable string, still sortable) +- Non configured, you don't need set a unique machine and/or data center id +- K-ordered +- Embedded time with 1 second precision +- Unicity guaranteed for 16,777,216 (24 bits) unique ids per second and per host/process +- Lock-free (i.e.: unlike UUIDv1 and v2) + +Best used with [zerolog](https://github.com/rs/zerolog)'s +[RequestIDHandler](https://godoc.org/github.com/rs/zerolog/hlog#RequestIDHandler). + +Notes: + +- Xid is dependent on the system time, a monotonic counter and so is not cryptographically secure. If unpredictability of IDs is important, you should not use Xids. It is worth noting that most other UUID-like implementations are also not cryptographically secure. You should use libraries that rely on cryptographically secure sources (like /dev/urandom on unix, crypto/rand in golang), if you want a truly random ID generator. + +References: + +- http://www.slideshare.net/davegardnerisme/unique-id-generation-in-distributed-systems +- https://en.wikipedia.org/wiki/Universally_unique_identifier +- https://blog.twitter.com/2010/announcing-snowflake +- Python port by [Graham Abbott](https://github.com/graham): https://github.com/graham/python_xid +- Scala port by [Egor Kolotaev](https://github.com/kolotaev): https://github.com/kolotaev/ride +- Rust port by [Jérôme Renard](https://github.com/jeromer/): https://github.com/jeromer/libxid +- Ruby port by [Valar](https://github.com/valarpirai/): https://github.com/valarpirai/ruby_xid +- Java port by [0xShamil](https://github.com/0xShamil/): https://github.com/0xShamil/java-xid +- Dart port by [Peter Bwire](https://github.com/pitabwire): https://pub.dev/packages/xid +- PostgreSQL port by [Rasmus Holm](https://github.com/crholm): https://github.com/modfin/pg-xid +- Swift port by [Uditha Atukorala](https://github.com/uditha-atukorala): https://github.com/uditha-atukorala/swift-xid +- C++ port by [Uditha Atukorala](https://github.com/uditha-atukorala): https://github.com/uditha-atukorala/libxid + +## Install + + go get github.com/rs/xid + +## Usage + +```go +guid := xid.New() + +println(guid.String()) +// Output: 9m4e2mr0ui3e8a215n4g +``` + +Get `xid` embedded info: + +```go +guid.Machine() +guid.Pid() +guid.Time() +guid.Counter() +``` + +## Benchmark + +Benchmark against Go [Maxim Bublis](https://github.com/satori)'s [UUID](https://github.com/satori/go.uuid). + +``` +BenchmarkXID 20000000 91.1 ns/op 32 B/op 1 allocs/op +BenchmarkXID-2 20000000 55.9 ns/op 32 B/op 1 allocs/op +BenchmarkXID-4 50000000 32.3 ns/op 32 B/op 1 allocs/op +BenchmarkUUIDv1 10000000 204 ns/op 48 B/op 1 allocs/op +BenchmarkUUIDv1-2 10000000 160 ns/op 48 B/op 1 allocs/op +BenchmarkUUIDv1-4 10000000 195 ns/op 48 B/op 1 allocs/op +BenchmarkUUIDv4 1000000 1503 ns/op 64 B/op 2 allocs/op +BenchmarkUUIDv4-2 1000000 1427 ns/op 64 B/op 2 allocs/op +BenchmarkUUIDv4-4 1000000 1452 ns/op 64 B/op 2 allocs/op +``` + +Note: UUIDv1 requires a global lock, hence the performance degradation as we add more CPUs. + +## Licenses + +All source code is licensed under the [MIT License](https://raw.github.com/rs/xid/master/LICENSE). -- cgit v1.2.3