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Ben Ramsey
32 lines
1.1 KiB
ReStructuredText
32 lines
1.1 KiB
ReStructuredText
============
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Introduction
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============
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ramsey/uuid is a PHP library for generating and working with `RFC 4122`_ version
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1, 2, 3, 4, and 5 universally unique identifiers (UUID). ramsey/uuid also
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supports optional and non-standard features, such as `version 6 UUIDs`_,
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`GUIDs`_, and other approaches for encoding/decoding UUIDs.
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What Is a UUID?
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###############
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A universally unique identifier, or UUID, is a 128-bit unsigned integer, usually
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represented as a hexadecimal string split into five groups with dashes. The most
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widely-known and used types of UUIDs are defined by `RFC 4122`_.
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A UUID, when encoded in hexadecimal string format, looks like:
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.. code-block:: text
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ebb5c735-0308-4e3c-9aea-8a270aebfe15
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The probability of duplicating a UUID is close to zero, so they are a great
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choice for generating unique identifiers in distributed systems.
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UUIDs can also be stored in binary format, as a string of 16 bytes.
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.. _RFC 4122: https://tools.ietf.org/html/rfc4122
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.. _version 6 UUIDs: http://gh.peabody.io/uuidv6/
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.. _GUIDs: https://docs.microsoft.com/en-us/dotnet/api/system.guid
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