Specialize LocalDate.until to avoid intermediate clamping

Author: ilya-g

core/commonMain/src/LocalDate.kt

@@ -50,6 +50,8 @@ expect fun LocalDate.periodUntil(other: LocalDate): DatePeriod
 /** */
 operator fun LocalDate.minus(other: LocalDate): DatePeriod = other.periodUntil(this)
 
+public expect fun LocalDate.until(other: LocalDate, unit: DateTimeUnit.DateBased): Int
+
 public expect fun LocalDate.daysUntil(other: LocalDate): Int
 public expect fun LocalDate.monthsUntil(other: LocalDate): Int
 public expect fun LocalDate.yearsUntil(other: LocalDate): Int
@@ -68,8 +70,3 @@ public expect fun LocalDate.plus(value: Int, unit: DateTimeUnit.DateBased): Loca
  * @throws DateTimeArithmeticException if the result exceeds the boundaries of [LocalDate].
  */
 public expect fun LocalDate.plus(value: Long, unit: DateTimeUnit.DateBased): LocalDate
-
-public fun LocalDate.until(other: LocalDate, unit: DateTimeUnit.DateBased): Int = when(unit) {
-    is DateTimeUnit.DateBased.MonthBased -> monthsUntil(other) / unit.months
-    is DateTimeUnit.DateBased.DayBased -> daysUntil(other) / unit.days
-}

core/commonTest/src/LocalDateTest.kt

@@ -144,8 +144,7 @@ class LocalDateTest {
         val diffDays = LocalDate.MIN.until(LocalDate.MAX, unit1000days)
         val diffYears = LocalDate.MIN.until(LocalDate.MAX, unit4years)
         assertTrue(diffDays in 0..Int.MAX_VALUE, "difference in $unit1000days should fit in Int, was $diffDays")
-        // TODO: make pass in JVM
-        //  assertTrue(diffDays > diffYears, "difference in $unit1000days unit must be more than in $unit4years unit, was $diffDays $diffYears")
+        assertTrue(diffDays > diffYears, "difference in $unit1000days unit must be more than in $unit4years unit, was $diffDays $diffYears")
     }
 
     @Test

core/jsMain/src/LocalDate.kt

@@ -86,6 +86,11 @@ public actual fun LocalDate.periodUntil(other: LocalDate): DatePeriod {
     return DatePeriod(months / 12, months % 12, days)
 }
 
+public actual fun LocalDate.until(other: LocalDate, unit: DateTimeUnit.DateBased): Int = when(unit) {
+    is DateTimeUnit.DateBased.MonthBased -> monthsUntil(other) / unit.months
+    is DateTimeUnit.DateBased.DayBased -> daysUntil(other) / unit.days
+}
+
 public actual fun LocalDate.daysUntil(other: LocalDate): Int =
         this.value.until(other.value, ChronoUnit.DAYS).toInt()
 

core/jvmMain/src/LocalDate.kt

@@ -100,6 +100,11 @@ public actual fun LocalDate.periodUntil(other: LocalDate): DatePeriod {
     return DatePeriod((months / 12).toInt(), (months % 12).toInt(), days.toInt())
 }
 
+public actual fun LocalDate.until(other: LocalDate, unit: DateTimeUnit.DateBased): Int = when(unit) {
+    is DateTimeUnit.DateBased.MonthBased -> (this.value.until(other.value, ChronoUnit.MONTHS) / unit.months).clampToInt()
+    is DateTimeUnit.DateBased.DayBased -> (this.value.until(other.value, ChronoUnit.DAYS) / unit.days).clampToInt()
+}
+
 public actual fun LocalDate.daysUntil(other: LocalDate): Int =
         this.value.until(other.value, ChronoUnit.DAYS).clampToInt()
 

core/nativeMain/src/LocalDate.kt

@@ -276,6 +276,11 @@ actual operator fun LocalDate.plus(period: DatePeriod): LocalDate =
         }
     }
 
+public actual fun LocalDate.until(other: LocalDate, unit: DateTimeUnit.DateBased): Int = when(unit) {
+    is DateTimeUnit.DateBased.MonthBased -> monthsUntil(other) / unit.months
+    is DateTimeUnit.DateBased.DayBased -> daysUntil(other) / unit.days
+}
+
 // org.threeten.bp.LocalDate#daysUntil
 public actual fun LocalDate.daysUntil(other: LocalDate): Int =
     other.toEpochDay() - this.toEpochDay()