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std.uuid


Category	Functions
Parsing UUIDs	parseUUID UUID(string) UUIDParsingException uuidRegex
Generating UUIDs	sha1UUID randomUUID md5UUID
Using UUIDs	UUID.uuidVersion UUID.variant UUID.toString UUID.data UUID.swap UUID.opEquals UUID.opCmp UUID.toHash
UUID namespaces	dnsNamespace urlNamespace oidNamespace x500Namespace

A UUID, or Universally unique identifier, is intended to uniquely identify information in a distributed environment without significant central coordination. It can be used to tag objects with very short lifetimes, or to reliably identify very persistent objects across a network.

UUIDs have many applications. Some examples follow: Databases may use UUIDs to identify rows or records in order to ensure that they are unique across different databases, or for publication/subscription services. Network messages may be identified with a UUID to ensure that different parts of a message are put back together again. Distributed computing may use UUIDs to identify a remote procedure call. Transactions and classes involved in serialization may be identified by UUIDs. Microsoft's component object model (COM) uses UUIDs to distinguish different software component interfaces. UUIDs are inserted into documents from Microsoft Office programs. UUIDs identify audio or video streams in the Advanced Systems Format (ASF). UUIDs are also a basis for OIDs (object identifiers), and URNs (uniform resource name).

An attractive feature of UUIDs when compared to alternatives is their relative small size, of 128 bits, or 16 bytes. Another is that the creation of UUIDs does not require a centralized authority.

When UUIDs are generated by one of the defined mechanisms, they are either guaranteed to be unique, different from all other generated UUIDs (that is, it has never been generated before and it will never be generated again), or it is extremely likely to be unique (depending on the mechanism).

For efficiency, UUID is implemented as a struct. UUIDs are therefore empty if not explicitly initialized. An UUID is empty if UUID.empty is true. Empty UUIDs are equal to UUID.init, which is a UUID with all 16 bytes set to 0. Use UUID's constructors or the UUID generator functions to get an initialized UUID.

This is a port of boost.uuid from the Boost project with some minor additions and API changes for a more D-like API.

Examples:

 UUID[] ids;
 ids ~= randomUUID();
 ids ~= md5UUID("test.name.123");
 ids ~= sha1UUID("test.name.123");

 foreach(entry; ids)
 {
     assert(entry.variant == UUID.Variant.rfc4122);
 }

 assert(ids[0].uuidVersion == UUID.Version.randomNumberBased);
 assert(ids[1].toString() == "22390768-cced-325f-8f0f-cfeaa19d0ccd");
 assert(ids[1].data == [34, 57, 7, 104, 204, 237, 50, 95, 143, 15, 207,
     234, 161, 157, 12, 205]);

 UUID id;
 assert(id.empty);

Standards:
RFC 4122

License:
Boost License 1.0

Authors:
Johannes Pfau

Source:
std/uuid.d

struct UUID;

enum Variant;

RFC 4122 defines different internal data layouts for UUIDs. These are the UUID formats supported by this module. It's possible to read, compare and use all these Variants, but UUIDs generated by this module will always be in rfc4122 format.

Note:
Do not confuse this with std.variant.Variant. This has nothing to do with std.variant.Variant.

ncs: NCS backward compatibility
rfc4122: Defined in RFC 4122 document
microsoft: Microsoft Corporation backward compatibility
future: Reserved for future use

enum Version;

RFC 4122 defines different UUID versions. The version shows how a UUID was generated, e.g. a version 4 UUID was generated from a random number, a version 3 UUID from an MD5 hash of a name.

Note:
All of these UUID versions can be read and processed by std.uuid, but only version 3, 4 and 5 UUIDs can be generated.

unknown: Unknown version
timeBased: Version 1
dceSecurity: Version 2
nameBasedMD5: Version 3 (Name based + MD5)
randomNumberBased: Version 4 (Random)
nameBasedSHA1: Version 5 (Name based + SHA-1)

ubyte[16] data;

It is sometimes useful to get or set the 16 bytes of a UUID directly.

Note:
UUID uses a 16-ubyte representation for the UUID data. RFC 4122 defines a UUID as a special structure in big-endian format. These 16-ubytes always equal the big-endian structure defined in RFC 4122.

Examples:

 auto rawData = uuid.data; //get data
 rawData[0] = 1; //modify
 uuid.data = rawData; //set data
 uuid.data[1] = 2; //modify directly

this()(ubyte[16] uuidData);

Construct a UUID struct from the 16 byte representation of a UUID.

Examples:

 ubyte[16] data = [0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15];
 auto tmp = UUID(data);
 assert(tmp.data == data);

this(T)(T[] uuid);

Parse a UUID from its canonical string form. An UUID in its canonical form looks like this: 8ab3060e-2cba-4f23-b74c-b52db3bdfb46

Throws:
UUIDParsingException if the input is invalid

CTFE:
This function is supported in CTFE code. Note that error messages caused by a malformed UUID parsed at compile time can be cryptic, but errors are detected and reported at compile time.

Note:
This is a strict parser. It only accepts the pattern above. It doesn't support any leading or trailing characters. It only accepts characters used for hex numbers and the string must have hyphens exactly like above.

For a less strict parser, see parseUUID

Examples:

 id = UUID("8AB3060E-2cba-4f23-b74c-b52db3bdfb46");
 assert(id.data == [138, 179, 6, 14, 44, 186, 79, 35, 183, 76,
    181, 45, 179, 189, 251, 70]);
 assert(id.toString() == "8ab3060e-2cba-4f23-b74c-b52db3bdfb46");

 //Can also be used in CTFE, for example as UUID literals:
 enum ctfeID = UUID("8ab3060e-2cba-4f23-b74c-b52db3bdfb46");
 //here parsing is done at compile time, no runtime overhead!

BUGS:
Could be pure, but this depends on parse!(string, 16).

const pure nothrow @property @trusted bool empty();

Returns true if and only if the UUID is equal to {00000000-0000-0000-0000-000000000000}

Examples:

 UUID id;
 assert(id.empty);
 id = UUID("00000000-0000-0000-0000-000000000001");
 assert(!id.empty);

const pure nothrow @property @safe Variant variant();

RFC 4122 defines different internal data layouts for UUIDs. Returns the format used by this UUID.

Note:
Do not confuse this with std.variant.Variant. This has nothing to do with std.variant.Variant. The type of this property is std.uuid.UUID.Variant.

See Also:
UUID.Variant

Examples:

 assert(UUID("8ab3060e-2cba-4f23-b74c-b52db3bdfb46").variant
     == UUID.Variant.rfc4122);

const pure nothrow @property @safe Version uuidVersion();

RFC 4122 defines different UUID versions. The version shows how a UUID was generated, e.g. a version 4 UUID was generated from a random number, a version 3 UUID from an MD5 hash of a name. Returns the version used by this UUID.

See Also:
UUID.Version

Examples:

  assert(UUID("8ab3060e-2cba-4f23-b74c-b52db3bdfb46").uuidVersion
      == UUID.Version.randomNumberBased);

nothrow @safe void swap(ref UUID rhs);

Swap the data of this UUID with the data of rhs.

Note:
linear complexity

Examples:

 UUID u1;
 auto u2 = UUID(cast(ubyte[16])[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15]);
 u1.swap(u2);

 assert(u1.data == cast(ubyte[16])[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15]);
 assert(u2.data == cast(ubyte[16])[0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]);

const pure nothrow @safe bool opEquals(const UUID s); const pure nothrow @safe bool opEquals(ref const UUID s); const pure nothrow @safe int opCmp(ref const UUID s); const pure nothrow @safe int opCmp(const UUID s); const pure nothrow @safe size_t toHash();

All of the standard numeric operators are defined for the UUID struct.

Examples:

 //compare UUIDs
 assert(UUID("00000000-0000-0000-0000-000000000000") == UUID.init);

 //UUIDs in associative arrays:
 int[UUID] test = [UUID("8a94f585-d180-44f7-8929-6fca0189c7d0") : 1,
     UUID("7c351fd4-b860-4ee3-bbdc-7f79f3dfb00a") : 2,
     UUID("9ac0a4e5-10ee-493a-86fc-d29eeb82ecc1") : 3];

 assert(test[UUID("9ac0a4e5-10ee-493a-86fc-d29eeb82ecc1")] == 3);

 //UUIDS can be sorted:
 import std.algorithm;
 UUID[] ids = [UUID("8a94f585-d180-44f7-8929-6fca0189c7d0"),
               UUID("7c351fd4-b860-4ee3-bbdc-7f79f3dfb00a"),
               UUID("9ac0a4e5-10ee-493a-86fc-d29eeb82ecc1")];
 sort(ids);

const void toString(scope void delegate(const(char)[]) sink); const pure nothrow @safe string toString();

Return the UUID as a string in the canonical form.

Examples:

 auto id = UUID("8ab3060e-2cba-4f23-b74c-b52db3bdfb46");
 assert(id.toString() == "8ab3060e-2cba-4f23-b74c-b52db3bdfb46");

pure @safe UUID md5UUID(const(char[]) name, const UUID namespace = (UUID).init); pure @trusted UUID md5UUID(const(ubyte[]) data, const UUID namespace = (UUID).init);

This function generates a name based (Version 3) UUID from a namespace UUID and a name. If no namespace UUID was passed, the empty UUID UUID.init is used.

Note:
The default namespaces (dnsNamespace, ...) defined by this module should be used when appropriate.

RFC 4122 recommends to use Version 5 UUIDs (SHA-1) instead of Version 3 UUIDs (MD5) for new applications.

CTFE:
CTFE is not supported.

Examples:

 //Use default UUID.init namespace
 auto simpleID = md5UUID("test.uuid.any.string");

 //use a name-based id as namespace
 auto namespace = md5UUID("my.app");
 auto id = md5UUID("some-description", namespace);

Note:
RFC 4122 isn't very clear on how UUIDs should be generated from names. It is possible that different implementations return different UUIDs for the same input, so be warned. The implementation for UTF-8 strings and byte arrays used by std.uuid is compatible with Boost's implementation. std.uuid guarantees that the same input to this function will generate the same output at any time, on any system (this especially means endianness doesn't matter).

Note:
This function does not provide overloads for wstring and dstring, as there's no clear answer on how that should be implemented. It could be argued, that string, wstring and dstring input should have the same output, but that wouldn't be compatible with Boost, which generates different output for strings and wstrings. It's always possible to pass wstrings and dstrings by using the ubyte[] function overload (but be aware of endianness issues!).

pure @trusted UUID sha1UUID(const(char[]) name, const UUID namespace = (UUID).init); pure @trusted UUID sha1UUID(const(ubyte[]) data, const UUID namespace = (UUID).init);

This function generates a name based (Version 5) UUID from a namespace UUID and a name. If no namespace UUID was passed, the empty UUID UUID.init is used.

Note:
The default namespaces (dnsNamespace, ...) defined by this module should be used when appropriate.

CTFE:
CTFE is not supported.

Examples:

 //Use default UUID.init namespace
 auto simpleID = sha1UUID("test.uuid.any.string");

 //use a name-based id as namespace
 auto namespace = sha1UUID("my.app");
 auto id = sha1UUID("some-description", namespace);

UUID randomUUID()(); UUID randomUUID(RNG)(ref RNG randomGen);

This function generates a random number based UUID from a random number generator.

CTFE:
This function is not supported at compile time.

Examples:

 //simple call
 auto uuid = randomUUID();

 //provide a custom RNG. Must be seeded manually.
 Xorshift192 gen;

 gen.seed(unpredictableSeed);
 auto uuid3 = randomUUID(gen);

UUID parseUUID(T)(T uuidString); UUID parseUUID(Range)(ref Range uuidRange);

This is a less strict parser compared to the parser used in the UUID constructor. It enforces the following rules:

hex numbers are always two hexdigits([0-9a-fA-F])
there must be exactly 16 such pairs in the input, not less, not more
there can be exactly one dash between two hex-pairs, but not more
there can be multiple characters enclosing the 16 hex pairs, as long as these characters do not contain [0-9a-fA-F]

Throws:
UUIDParsingException if the input is invalid

CTFE:
This function is supported in CTFE code. Note that error messages caused by a malformed UUID parsed at compile time can be cryptic, but errors are detected and reported at compile time.

Examples:

 auto id = parseUUID("8AB3060E-2CBA-4F23-b74c-B52Db3BDFB46");
 //no dashes
 id = parseUUID("8ab3060e2cba4f23b74cb52db3bdfb46");
 //dashes at different positions
 id = parseUUID("8a-b3-06-0e2cba4f23b74c-b52db3bdfb-46");
 //leading / trailing characters
 id = parseUUID("{8ab3060e-2cba-4f23-b74c-b52db3bdfb46}");
 //unicode
 id = parseUUID("ü8ab3060e2cba4f23b74cb52db3bdfb46ü");
 //multiple trailing/leading characters
 id = parseUUID("///8ab3060e2cba4f23b74cb52db3bdfb46||");

 //Can also be used in CTFE, for example as UUID literals:
 enum ctfeID = parseUUID("8ab3060e-2cba-4f23-b74c-b52db3bdfb46");
 //here parsing is done at compile time, no runtime overhead!

BUGS:
Could be pure, but this depends on parse!(string, 16).

UUID dnsNamespace;

Default namespace from RFC 4122

Name string is a fully-qualified domain name

UUID urlNamespace;

Default namespace from RFC 4122

Name string is a URL

UUID oidNamespace;

Default namespace from RFC 4122

Name string is an ISO OID

UUID x500Namespace;

Default namespace from RFC 4122

Name string is an X.500 DN (in DER or a text output format)

string uuidRegex;

Regex string to extract UUIDs from text.

Examples:

 import std.algorithm;
 import std.regex;

 string test = "Lorem ipsum dolor sit amet, consetetur "
     "6ba7b814-9dad-11d1-80b4-00c04fd430c8 sadipscing \n"
     "elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore \r\n"
     "magna aliquyam erat, sed diam voluptua. "
     "8ab3060e-2cba-4f23-b74c-b52db3bdfb46 At vero eos et accusam et "
     "justo duo dolores et ea rebum.";

 auto r = regex(uuidRegex, "g");

 UUID[] found;
 foreach(c; match(test, r))
 {
     found ~= UUID(c.hit);
 }

 writeln(found);

class UUIDParsingException: object.Exception;

This exception is thrown if an error occurs when parsing a UUID from a string.

enum Reason; Reason reason;

The reason why parsing the UUID string failed (if known)

unknown
tooLittle: The passed in input was correct, but more input was expected.
tooMuch: The input data is too long (There's no guarantee the first part of the data is valid)
invalidChar: Encountered an invalid character

string input;

The original input string which should have been parsed.

size_t position;

The position in the input string where the error occurred.

std

etc

core

std.uuid