Optionally rely on cl-trivial-clock for more accurate timestamps

README.org

@@ -119,6 +119,8 @@ function.
 The above system is provided to conveniently setup the following:
 
 - Use Ironclad PRNG to generate [[https://github.com/ak-coram/cl-frugal-uuid/blob/main/non-frugal/strong-random.lisp][strong random numbers]].
+- Use [[https://github.com/ak-coram/cl-trivial-clock][cl-trivial-clock]] to generate more accurate timestamps by relying
+  on platform-specific functionality.
 - Automatically use a new PRNG and randomize node ID & clock sequence
   for generating version 1 UUIDs for each new thread (via
   [[https://github.com/ak-coram/cl-frugal-uuid/blob/main/non-frugal/thread-safe.lisp][bordeaux-threads]]).

frugal-uuid-v1.lisp

@@ -12,17 +12,19 @@
    (timestamp-generator :initarg :v1-timestamp-generator
                         :accessor v1-timestamp-generator)))
 
-(defvar *v1-generator* nil)
-
 (defun make-v1-generator (&key node-id clock-seq timestamp-generator)
   (make-instance 'v1-generator
                  :v1-node-id (or node-id (random-node-id))
                  :v1-clock-seq (or clock-seq (random-clock-seq))
                  :v1-timestamp-generator (or timestamp-generator
                                              (make-timestamp-generator))))
 
+(defvar *v1-generator* nil)
+(defvar *v1-generator-init-function* #'make-v1-generator)
+
 (defun initialize-v1-generator (&optional v1-generator)
-  (setf *v1-generator* (or v1-generator (make-v1-generator)))
+  (setf *v1-generator* (or v1-generator
+                           (funcall *v1-generator-init-function*)))
   nil)
 
 (defmacro with-v1-generator (v1-generator &body body)
@@ -54,4 +56,3 @@
   "Generate uuid value (version 1)."
   (unless *v1-generator* (initialize-v1-generator))
   (make-v1-from-timestamp (funcall (v1-timestamp-generator *v1-generator*))))
-

frugal-uuid.asd

@@ -41,10 +41,16 @@
                #:ironclad/digest/sha1)
   :components ((:file "non-frugal/name-based")))
 
+(asdf:defsystem #:frugal-uuid/non-frugal/accurate-clock
+  :depends-on (#:frugal-uuid
+               #:trivial-clock)
+  :components ((:file "non-frugal/accurate-clock")))
+
 (asdf:defsystem #:frugal-uuid/non-frugal
   :depends-on (#:frugal-uuid/non-frugal/strong-random
                #:frugal-uuid/non-frugal/thread-safe
-               #:frugal-uuid/non-frugal/name-based))
+               #:frugal-uuid/non-frugal/name-based
+               #:frugal-uuid/non-frugal/accurate-clock))
 
 (asdf:defsystem #:frugal-uuid/benchmark
   :depends-on (#:frugal-uuid

non-frugal/accurate-clock.lisp

@@ -0,0 +1,18 @@
+;;;; non-frugal/accurate-clock.lisp
+
+(in-package #:frugal-uuid)
+
+(defconstant +unix-epoch-offset-seconds+ 12219292800)
+
+(defun get-accurate-timestamp ()
+  (multiple-value-bind (seconds nanos) (trivial-clock:now)
+    (+ (* (+ seconds +unix-epoch-offset-seconds+) 10000000)
+       (floor nanos 100))))
+
+(defun make-accurate-v1-generator (&key node-id clock-seq)
+  (make-v1-generator :node-id node-id
+                     :clock-seq clock-seq
+                     :timestamp-generator #'get-accurate-timestamp))
+
+(setf *v1-generator* nil
+      *v1-generator-init-function* #'make-accurate-v1-generator)

package.lisp

@@ -49,7 +49,9 @@
 
            ;; Version 1
            #:*v1-generator*
+           #:*v1-generator-init-function*
            #:make-v1-generator
+           #:make-accurate-v1-generator
            #:initialize-v1-generator
            #:with-v1-generator
            #:make-v1-from-timestamp