rand: add rand.ulid() (#5979)

* removed debug println

* added newline to the end of the file

* time: add .unix_time_milli() method; rand,time: add tests

* rand: add more ulid tests; move tests to a separate file random_identifiers_test.v

* run vfmt over vlib/rand/random_identifiers_test.v

* speed up time.unix_time_milli

* simplify and speedup time.unix_time/0 and time.new_time/1

* update comment about rand.ulid()

* fix terminating 0 off by 1 issue in rand.ulid()

* optimize time.new_time()

* restore the master version of vlib/time/parse.v

* make test_unix_time more robust

Co-authored-by: Delyan Angelov <delian66@gmail.com>

vlib/time/time.v

@@ -138,27 +138,8 @@ pub fn (t Time) smonth() string {
 
 // new_time returns a time struct with calculated Unix time.
 pub fn new_time(t Time) Time {
-	return Time{
-		year: t.year
-		month: t.month
-		day: t.day
-		hour: t.hour
-		minute: t.minute
-		second: t.second
-		unix: u64(t.unix_time())
-		microsecond: t.microsecond
-	}
-	// TODO Use the syntax below when it works with reserved keywords like `unix`
-	// return {
-	// 	t |
-	// 	unix:t.unix_time()
-	// }
-}
-
-// unix_time returns Unix time.
-pub fn (t Time) unix_time() int {
 	if t.unix != 0 {
-		return int(t.unix)
+		return t
 	}
 	tt := C.tm{
 		tm_sec: t.second
@@ -168,7 +149,20 @@ pub fn (t Time) unix_time() int {
 		tm_mon: t.month - 1
 		tm_year: t.year - 1900
 	}
-	return make_unix_time(tt)
+	utime := u64(make_unix_time(tt))
+	return { t | unix: utime }
+}
+
+// unix_time returns Unix time.
+[inline]
+pub fn (t Time) unix_time() int {
+	return int(t.unix)
+}
+
+// unix_time_milli returns Unix time with millisecond resolution.
+[inline]
+pub fn (t Time) unix_time_milli() u64 {
+	return t.unix * 1000 + u64(t.microsecond/1000)
 }
 
 // add_seconds returns a new time struct with an added number of seconds.

vlib/time/time_test.v

@@ -192,3 +192,21 @@ fn test_utc() {
 	assert now.microsecond 		>= 0
 	assert now.microsecond 		< 1000000
 }
+
+fn test_unix_time() {
+	t1 := time.utc()
+	time.sleep_ms(50)
+	t2 := time.utc()
+	ut1 := t1.unix_time()
+	ut2 := t2.unix_time()
+	assert ut2 - ut1 < 2
+	//
+	utm1 := t1.unix_time_milli()
+	utm2 := t2.unix_time_milli()
+	assert (utm1 - u64(ut1)*1000) < 1000
+	assert (utm2 - u64(ut2)*1000) < 1000
+	//
+	//println('utm1: $utm1 | utm2: $utm2')
+	assert utm2 - utm1 > 2
+	assert utm2 - utm1 < 999
+}