PHP generates GUID (Globally Unique Identifier) ​​method analysis

This article introduces how PHP generates GUID, which is a globally unique identifier. Friends in need can refer to it.
GUID: Globally Unique Identifier (Globally Unique Identifier), also known as UUID (Universally Unique IDentifier).

GUID is a 128-bit binary numeric identifier generated by a specific algorithm and used to indicate

Product uniqueness. GUID is mainly used to assign unique identifiers in a network or system with multiple nodes and computers.

On the Windows platform, GUID is widely used in Microsoft products to identify objects such as registry keys, class and interface identifiers, databases, and system directories.

The format of the GUID is "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx", where each x is a 32-bit hexadecimal number in the range 0-9 or a-f.

For example: 6F9619FF-8B86-D011-B42D-00C04FC964FF is a valid GUID value.

GUID is unique in space and time, ensuring that different numbers generated in different places at the same time are different.
No two computers in the world will generate duplicate GUID values.
When a GUID is needed, it can be completely automatically generated by the algorithm and does not require an authoritative organization to manage it.
GUIDs have a fixed length and are relatively short, making them ideal for sorting, identification, and storage.

//php generates 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(125);// "}"
return $uuid;
}