Acknowledgements

This project makes use of and was inspired by code from:

• Hypersequent/uuid7 (MIT License)
• google/uuid (BSD License)

UUIDv7

This package implement rfc9562 Section 5.7. UUID Version 7.

The origin structure of UUID Version 7 are following the structure below:

 0                   1                   2                   3
 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                           unix_ts_ms                          |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|          unix_ts_ms           |  ver  |       rand_a          |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|var|                        rand_b                             |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|                            rand_b                             |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

• unix_ts_ms: 48-bit big-endian unsigned number of the Unix Epoch timestamp in milliseconds as per Section 6.1. Occupies bits 0 through 47 (octets 0-5).
• ver: The 4-bit version field as defined by Section 4.2, set to 0b0111 (7). Occupies bits 48 through 51 of octet 6.
• rand_a: 12 bits of pseudorandom data to provide uniqueness as per Section 6.9 and/or optional constructs to guarantee additional monotonicity as per Section 6.2. Occupies bits 52 through 63 (octets 6-7).
• var: The 2-bit variant field as defined by Section 4.1, set to 0b10. Occupies bits 64 and 65 of octet 8.
• rand_b: The final 62 bits of pseudorandom data to provide uniqueness as per Section 6.9 and/or an optional counter to guarantee additional monotonicity as per Section 6.2. Occupies bits 66 through 127 (octets 8-15).