Simplify

Author: dkhalanskyjb

core/native/src/Instant.kt

@@ -36,7 +36,7 @@ private const val MIN_SECOND = -31619119219200L // -1000000-01-01T00:00:00Z
  */
 private const val MAX_SECOND = 31494816403199L // +1000000-12-31T23:59:59
 
-private fun isValidInstantSecond(second: Long) = second >= MIN_SECOND && second <= MAX_SECOND
+private fun isValidInstantSecond(second: Long) = second in MIN_SECOND..MAX_SECOND
 
 @Serializable(with = InstantIso8601Serializer::class)
 public actual class Instant internal constructor(public actual val epochSeconds: Long, public actual val nanosecondsOfSecond: Int) : Comparable<Instant> {
@@ -54,14 +54,11 @@ public actual class Instant internal constructor(public actual val epochSeconds:
      * @throws ArithmeticException if arithmetic overflow occurs
      * @throws IllegalArgumentException if the boundaries of Instant are overflown
      */
-    internal fun plus(secondsToAdd: Long, nanosToAdd: Long): Instant {
-        if ((secondsToAdd or nanosToAdd) == 0L) {
-            return this
-        }
+    internal fun plus(secondsToAdd: Long, nanosToAdd: Long): Instant = onNonZero(secondsToAdd or nanosToAdd) {
         val newEpochSeconds: Long = safeAdd(safeAdd(epochSeconds, secondsToAdd), (nanosToAdd / NANOS_PER_ONE))
         val newNanosToAdd = nanosToAdd % NANOS_PER_ONE
         val nanoAdjustment = (nanosecondsOfSecond + newNanosToAdd) // safe int+NANOS_PER_ONE
-        return fromEpochSecondsThrowing(newEpochSeconds, nanoAdjustment)
+        fromEpochSecondsThrowing(newEpochSeconds, nanoAdjustment)
     }
 
     public actual operator fun plus(duration: Duration): Instant = duration.toComponents { secondsToAdd, nanosecondsToAdd ->
@@ -81,10 +78,7 @@ public actual class Instant internal constructor(public actual val epochSeconds:
         (this.nanosecondsOfSecond - other.nanosecondsOfSecond).nanoseconds
 
     actual override fun compareTo(other: Instant): Int {
-        val s = epochSeconds.compareTo(other.epochSeconds)
-        if (s != 0) {
-            return s
-        }
+        onNonZero(epochSeconds.compareTo(other.epochSeconds)) { return it }
         return nanosecondsOfSecond.compareTo(other.nanosecondsOfSecond)
     }
 
@@ -150,27 +144,21 @@ public actual class Instant internal constructor(public actual val epochSeconds:
 
 }
 
-private fun Instant.toLocalDateTimeFailing(offset: UtcOffset): LocalDateTime = try {
-    toLocalDateTimeImpl(offset)
-} catch (e: IllegalArgumentException) {
-    throw DateTimeArithmeticException("Can not convert instant $this to LocalDateTime to perform computations", e)
-}
-
 /** Check that [Instant] fits in [LocalDateTime].
  * This is done on the results of computations for consistency with other platforms.
  */
 private fun Instant.check(zone: TimeZone): Instant = this@check.also {
-    toLocalDateTimeFailing(offsetIn(zone))
+    toLocalDateTime(offsetIn(zone))
 }
 
 public actual fun Instant.plus(period: DateTimePeriod, timeZone: TimeZone): Instant = try {
     with(period) {
         val initialOffset = offsetIn(timeZone)
-        val newLdt = toLocalDateTimeFailing(initialOffset)
-            .run { if (totalMonths != 0) { plus(totalMonths, DateTimeUnit.MONTH) } else { this } }
-            .run { if (days != 0) { plus(days, DateTimeUnit.DAY) } else { this } }
+        val newLdt = toLocalDateTime(initialOffset)
+            .run { onNonZero(totalMonths) { plus(it, DateTimeUnit.MONTH) } }
+            .run { onNonZero(days) { plus(it, DateTimeUnit.DAY) } }
         timeZone.localDateTimeToInstant(newLdt, preferred = initialOffset)
-            .run { if (totalNanoseconds != 0L) plus(0, totalNanoseconds).check(timeZone) else this }
+            .run { onNonZero(totalNanoseconds) { plus(totalNanoseconds, DateTimeUnit.NANOSECOND).check(timeZone) } }
     }.check(timeZone)
 } catch (e: ArithmeticException) {
     throw DateTimeArithmeticException("Arithmetic overflow when adding CalendarPeriod to an Instant", e)
@@ -191,7 +179,7 @@ public actual fun Instant.plus(value: Long, unit: DateTimeUnit, timeZone: TimeZo
             if (value < Int.MIN_VALUE || value > Int.MAX_VALUE)
                 throw ArithmeticException("Can't add a Long date-based value, as it would cause an overflow")
             val initialOffset = offsetIn(timeZone)
-            val initialLdt = toLocalDateTimeFailing(initialOffset)
+            val initialLdt = toLocalDateTime(initialOffset)
             timeZone.localDateTimeToInstant(initialLdt.plus(value.toInt(), unit), preferred = initialOffset)
         }
         is DateTimeUnit.TimeBased ->
@@ -216,13 +204,19 @@ public actual fun Instant.plus(value: Long, unit: DateTimeUnit.TimeBased): Insta
 
 public actual fun Instant.periodUntil(other: Instant, timeZone: TimeZone): DateTimePeriod {
     val initialOffset = offsetIn(timeZone)
-    val initialLdt = toLocalDateTimeFailing(initialOffset)
-    val otherLdt = other.toLocalDateTimeFailing(other.offsetIn(timeZone))
+    val initialLdt = toLocalDateTime(initialOffset)
+    val otherLdt = other.toLocalDateTime(other.offsetIn(timeZone))
 
     val months = initialLdt.until(otherLdt, DateTimeUnit.MONTH) // `until` on dates never fails
-    val ldtWithMonths = initialLdt.plus(months, DateTimeUnit.MONTH) // won't throw: thisLdt + months <= otherLdt, which is known to be valid
+    val ldtWithMonths = initialLdt.plus(
+        months,
+        DateTimeUnit.MONTH
+    ) // won't throw: thisLdt + months <= otherLdt, which is known to be valid
     val days = ldtWithMonths.until(otherLdt, DateTimeUnit.DAY) // `until` on dates never fails
-    val newInstant = timeZone.localDateTimeToInstant(ldtWithMonths.plus(days, DateTimeUnit.DAY), preferred = initialOffset) // won't throw: thisLdt + days <= otherLdt
+    val newInstant = timeZone.localDateTimeToInstant(
+        ldtWithMonths.plus(days, DateTimeUnit.DAY),
+        preferred = initialOffset
+    ) // won't throw: thisLdt + days <= otherLdt
     val nanoseconds = newInstant.until(other, DateTimeUnit.NANOSECOND) // |otherLdt - thisLdt| < 24h
 
     return buildDateTimePeriod(months, days, nanoseconds)
@@ -231,7 +225,7 @@ public actual fun Instant.periodUntil(other: Instant, timeZone: TimeZone): DateT
 public actual fun Instant.until(other: Instant, unit: DateTimeUnit, timeZone: TimeZone): Long =
     when (unit) {
         is DateTimeUnit.DateBased ->
-            toLocalDateTimeFailing(offsetIn(timeZone)).until(other.toLocalDateTimeFailing(other.offsetIn(timeZone)), unit)
+            toLocalDateTime(offsetIn(timeZone)).until(other.toLocalDateTime(other.offsetIn(timeZone)), unit)
                 .toLong()
         is DateTimeUnit.TimeBased -> {
             check(timeZone); other.check(timeZone)

core/native/src/LocalDate.kt

@@ -134,14 +134,8 @@ public actual class LocalDate actual constructor(public actual val year: Int, pu
 
     // Several times faster than using `compareBy`
     actual override fun compareTo(other: LocalDate): Int {
-        val y = year.compareTo(other.year)
-        if (y != 0) {
-            return y
-        }
-        val m = monthNumber.compareTo(other.monthNumber)
-        if (m != 0) {
-            return m
-        }
+        onNonZero(year.compareTo(other.year)) { return it }
+        onNonZero(monthNumber.compareTo(other.monthNumber)) { return it }
         return dayOfMonth.compareTo(other.dayOfMonth)
     }
 
@@ -159,15 +153,12 @@ public actual class LocalDate actual constructor(public actual val year: Int, pu
      * @throws IllegalArgumentException if the result exceeds the boundaries
      * @throws ArithmeticException if arithmetic overflow occurs
      */
-    internal fun plusMonths(monthsToAdd: Int): LocalDate {
-        if (monthsToAdd == 0) {
-            return this
-        }
+    internal fun plusMonths(monthsToAdd: Int): LocalDate = onNonZero(monthsToAdd) {
         val monthCount = year * 12 + (monthNumber - 1)
         val calcMonths = safeAdd(monthCount, monthsToAdd)
         val newYear = calcMonths.floorDiv(12)
         val newMonth = calcMonths.mod(12) + 1
-        return resolvePreviousValid(newYear, newMonth, dayOfMonth)
+        resolvePreviousValid(newYear, newMonth, dayOfMonth)
     }
 
     // org.threeten.bp.LocalDate#plusDays
@@ -176,8 +167,7 @@ public actual class LocalDate actual constructor(public actual val year: Int, pu
      * @throws ArithmeticException if arithmetic overflow occurs
      */
     internal fun plusDays(daysToAdd: Int): LocalDate =
-        if (daysToAdd == 0) this
-        else fromEpochDays(safeAdd(toEpochDays(), daysToAdd))
+        onNonZero(daysToAdd) { fromEpochDays(safeAdd(toEpochDays(), daysToAdd)) }
 
     override fun equals(other: Any?): Boolean =
         this === other || (other is LocalDate && compareTo(other) == 0)
@@ -221,8 +211,8 @@ public actual operator fun LocalDate.plus(period: DatePeriod): LocalDate =
     with(period) {
         try {
             this@plus
-                .run { if (totalMonths != 0) plusMonths(totalMonths) else this }
-                .run { if (days != 0) plusDays(days) else this }
+                .run { onNonZero(totalMonths) { plusMonths(it) } }
+                .run { onNonZero(days) { plusDays(days) } }
         } catch (e: ArithmeticException) {
             throw DateTimeArithmeticException("Arithmetic overflow when adding a period to a date", e)
         } catch (e: IllegalArgumentException) {

core/native/src/LocalDateTime.kt

@@ -51,10 +51,7 @@ public actual constructor(public actual val date: LocalDate, public actual val t
 
     // Several times faster than using `compareBy`
     actual override fun compareTo(other: LocalDateTime): Int {
-        val d = date.compareTo(other.date)
-        if (d != 0) {
-            return d
-        }
+        onNonZero(date.compareTo(other.date)) { return it }
         return time.compareTo(other.time)
     }
 
@@ -112,19 +109,15 @@ internal fun LocalDateTime.until(other: LocalDateTime, unit: DateTimeUnit.TimeBa
  * @throws IllegalArgumentException if the result exceeds the boundaries
  * @throws ArithmeticException if arithmetic overflow occurs
  */
-internal fun LocalDateTime.plusSeconds(seconds: Int): LocalDateTime
-{
-    if (seconds == 0) {
-        return this
-    }
+internal fun LocalDateTime.plusSeconds(seconds: Int): LocalDateTime = onNonZero(seconds) {
     val currentNanoOfDay = time.toNanosecondOfDay() // at most a day
     val totalNanos: Long = seconds % SECONDS_PER_DAY * NANOS_PER_ONE.toLong() + // at most a day
         currentNanoOfDay
     val totalDays = seconds / SECONDS_PER_DAY + // max/24*60*60 < max * 0.000012
         totalNanos.floorDiv(NANOS_PER_DAY) // max 2 days
     val newNanoOfDay: Long = totalNanos.mod(NANOS_PER_DAY)
     val newTime: LocalTime = if (newNanoOfDay == currentNanoOfDay) time else LocalTime.ofNanoOfDay(newNanoOfDay)
-    return LocalDateTime(date.plusDays(totalDays.toInt()), newTime)
+    LocalDateTime(date.plusDays(totalDays.toInt()), newTime)
 }
 
 private val ISO_DATETIME_OPTIONAL_SECONDS_TRAILING_ZEROS by lazy {

core/native/src/LocalTime.kt

@@ -86,18 +86,9 @@ public actual class LocalTime actual constructor(
 
     // Several times faster than using `compareBy`
     actual override fun compareTo(other: LocalTime): Int {
-        val h = hour.compareTo(other.hour)
-        if (h != 0) {
-            return h
-        }
-        val m = minute.compareTo(other.minute)
-        if (m != 0) {
-            return m
-        }
-        val s = second.compareTo(other.second)
-        if (s != 0) {
-            return s
-        }
+        onNonZero(hour.compareTo(other.hour)) { return it }
+        onNonZero(minute.compareTo(other.minute)) { return it }
+        onNonZero(second.compareTo(other.second)) { return it }
         return nanosecond.compareTo(other.nanosecond)
     }
 

core/native/src/TimeZone.kt

@@ -51,17 +51,12 @@ public actual open class TimeZone internal constructor() {
                 ) {
                     val prefix = zoneId.take(3)
                     val offset = lenientOffsetFormat.parse(zoneId.substring(3))
-                    return when (offset.totalSeconds) {
-                        0 -> FixedOffsetTimeZone(offset, prefix)
-                        else -> FixedOffsetTimeZone(offset, "$prefix$offset")
-                    }
+                    return FixedOffsetTimeZone(offset, prefix.onNonZero(offset.totalSeconds) { "$prefix$offset" })
                 }
                 if (zoneId.startsWith("UT+") || zoneId.startsWith("UT-")) {
                     val offset = lenientOffsetFormat.parse(zoneId.substring(2))
-                    return when (offset.totalSeconds) {
-                        0 -> FixedOffsetTimeZone(offset, "UT")
-                        else -> FixedOffsetTimeZone(offset, "UT$offset")
-                    }
+                    val prefix = "UT"
+                    return FixedOffsetTimeZone(offset, prefix.onNonZero(offset.totalSeconds) { "$prefix$offset"})
                 }
             } catch (e: DateTimeFormatException) {
                 throw IllegalTimeZoneException(e)
@@ -83,14 +78,11 @@ public actual open class TimeZone internal constructor() {
     public actual fun Instant.toLocalDateTime(): LocalDateTime = instantToLocalDateTime(this)
     public actual fun LocalDateTime.toInstant(): Instant = localDateTimeToInstant(this)
 
-    internal open fun atStartOfDay(date: LocalDate): Instant = error("Should be overridden") //value.atStartOfDay(date)
+    internal open fun atStartOfDay(date: LocalDate): Instant = error("Should be overridden")
     internal open fun offsetAtImpl(instant: Instant): UtcOffset = error("Should be overridden")
 
-    internal open fun instantToLocalDateTime(instant: Instant): LocalDateTime = try {
-        instant.toLocalDateTimeImpl(offsetAtImpl(instant))
-    } catch (e: IllegalArgumentException) {
-        throw DateTimeArithmeticException("Instant $instant is not representable as LocalDateTime.", e)
-    }
+    internal open fun instantToLocalDateTime(instant: Instant): LocalDateTime =
+        instant.toLocalDateTime(offsetAtImpl(instant))
 
     internal open fun localDateTimeToInstant(dateTime: LocalDateTime, preferred: UtcOffset? = null): Instant =
         error("Should be overridden")
@@ -118,8 +110,6 @@ public actual class FixedOffsetTimeZone internal constructor(public actual val o
 
     override fun localDateTimeToInstant(dateTime: LocalDateTime, preferred: UtcOffset?): Instant =
         dateTime.toInstant(offset)
-
-    override fun instantToLocalDateTime(instant: Instant): LocalDateTime = instant.toLocalDateTime(offset)
 }
 
 

core/native/src/internal/util.kt

@@ -0,0 +1,8 @@
+/*
+ * Copyright 2019-2023 JetBrains s.r.o. and contributors.
+ * Use of this source code is governed by the Apache 2.0 License that can be found in the LICENSE.txt file.
+ */
+
+package kotlinx.datetime.internal
+
+internal inline fun <A, T: Number> A.onNonZero(value: T, block: (T) -> A): A = if (value != 0) block(value) else this