Php GUID generation functions and Classes

1. Introduction to GUID
GUID: that is, Globally Unique Identifier (Globally Unique IDentifier) is also called UUID (Universally Unique Identifier ). GUID is a 128-bit digital identifier generated by a specific algorithm. It is used to indicate the uniqueness of a product. GUID is used to assign a unique identifier to a network or system with multiple nodes and computers.
On Windows, GUID is widely used in Microsoft products and is used to identify objects such as registry items, classes and interfaces, databases, and system directories.
The GUID format is "xxxxxxxx-xxxx-xxxxxxxxxxxx", where each x is a 32-bit hexadecimal number in the range of 0-9 or a-f. For example, 6F9619FF-8B86-D011-B42D-00C04FC964FF is a valid GUID value.
Ii. Advantages of GUID
1. GUID is unique in space and time to ensure that numbers are generated at different places at the same time.
2. No two computers in the world will generate duplicate GUID values.
3. When a GUID is required, it can be automatically generated by the algorithm without being managed by an authority.
4. The GUID has a fixed length and is relatively short and small. It is suitable for sorting, identification, and storage.
Iii. GUID generation function
Copy codeThe Code is as follows:
Function create_guid (){
$ Charid = strtoupper (md5 (uniqid (mt_rand (), true )));
$ Hyphen = chr (45 );//"-"
$ Uuid = chr (123 )//"{"
. Substr ($ charid, 0, 8). $ hyphen
. Substr ($ charid, 8, 4). $ hyphen
. Substr ($ charid, 12, 4). $ hyphen
. Substr ($ charid, 16, 4). $ hyphen
. Substr ($ charid, 20, 12)
. Chr (1, 125 );//"}"
Return $ uuid;
}

Iii. GUID generation class
PHP obtains the GUID class: guid_class.php
Copy codeThe Code is as follows:
<? Php
Class System
{
Function currentTimeMillis ()
{
List ($ usec, $ sec) = explode ("", microtime ());
Return $ sec. substr ($ usec, 2, 3 );
}
}
Class NetAddress
{
Var $ Name = 'localhost ';
Var $ IP = '1970. 0.0.1 ';
Function getLocalHost () // static
{
$ Address = new NetAddress ();
$ Address-> Name = $ _ ENV ["COMPUTERNAME"];
$ Address-> IP = $ _ SERVER ["SERVER_ADDR"];
Return $ address;
}
Function toString ()
{
Return strtolower ($ this-> Name. '/'. $ this-> IP );
}
}
Class Random
{
Function nextLong ()
{
$ Tmp = rand (0, 1 )? '-':'';
Return $ tmp. rand (1000,999 9). rand (1000,999 9). rand (1000,999 9). rand (100,999). rand (100,999 );
}
}
// Three paragraphs
// Segment is microsecond segment is address segment is random number
Class Guid
{
Var $ valueBeforeMD5;
Var $ valueAfterMD5;
Function Guid ()
{
$ This-> getGuid ();
}
//
Function getGuid ()
{
$ Address = NetAddress: getLocalHost ();
$ This-> valueBeforeMD5 = $ address-> toString (). ':'. System: currentTimeMillis (). ':'. Random: nextLong ();
$ This-> valueAfterMD5 = md5 ($ this-> valueBeforeMD5 );
}
Function newGuid ()
{
$ Guid = new Guid ();
Return $ Guid;
}
Function toString ()
{
$ Raw = strtoupper ($ this-> valueAfterMD5 );
Return substr ($ raw, 0, 8 ). '-'. substr ($ raw, 8, 4 ). '-'. substr ($ raw, 12, 4 ). '-'. substr ($ raw, 16, 4 ). '-'. substr ($ raw, 20 );
}
}

Usage of the GUID class:
Copy codeThe Code is as follows:
Require_once ("guid. class. php ");
$ Guid = new Guid ();
Print $ Guid-> toString ();