add util functions and checks

src/commonMain/kotlin/com/github/insanusmokrassar/krontab/CronDateTime.kt

@@ -0,0 +1,80 @@
+package com.github.insanusmokrassar.krontab
+
+import com.soywiz.klock.*
+import com.github.insanusmokrassar.krontab.utils.clamp
+
+private val incomeMonthRange = 0 .. 11
+private val incomeDayOfMonthRange = 0 .. 31
+private val incomeHourRange = 0 .. 23
+private val incomeMinuteRange = 0 .. 59
+private val incomeSecondRange = 0 .. 59
+
+fun CronDateTime(
+    month: Int? = null,
+    dayOfMonth: Int? = null,
+    hour: Int? = null,
+    minute: Int? = null,
+    second: Int? = null
+) = CronDateTime(
+    month ?.clamp(incomeMonthRange) ?.toByte(),
+    dayOfMonth ?.clamp(incomeDayOfMonthRange) ?.toByte(),
+    hour ?.clamp(incomeHourRange) ?.toByte(),
+    minute ?.clamp(incomeMinuteRange) ?.toByte(),
+    second ?.clamp(incomeSecondRange) ?.toByte()
+)
+
+/**
+ * [month] 0-11
+ * [dayOfMonth] 0-31
+ * [hour] 0-23
+ * [minute] 0-59
+ * [second] 0-59
+ */
+data class CronDateTime(
+    val month: Byte? = null,
+    val dayOfMonth: Byte? = null,
+    val hour: Byte? = null,
+    val minute: Byte? = null,
+    val second: Byte? = null
+) {
+    init {
+        check(month ?.let { it in incomeMonthRange } ?: true)
+        check(dayOfMonth ?.let { it in incomeDayOfMonthRange } ?: true)
+        check(hour ?.let { it in incomeHourRange } ?: true)
+        check(minute ?.let { it in incomeMinuteRange } ?: true)
+        check(second ?.let { it in incomeSecondRange } ?: true)
+    }
+
+    internal val klockDayOfMonth = dayOfMonth ?.plus(1)
+}
+
+fun CronDateTime.toNearDateTime(relativelyTo: DateTime = DateTime.now()): DateTime {
+    var current = relativelyTo
+
+    second ?.let {
+        val left = it - current.seconds
+        current += DateTimeSpan(minutes = if (left < 0) 1 else 0, seconds = left)
+    }
+
+    minute ?.let {
+        val left = it - current.minutes
+        current += DateTimeSpan(hours = if (left < 0) 1 else 0, minutes = left)
+    }
+
+    hour ?.let {
+        val left = it - current.hours
+        current += DateTimeSpan(days = if (left < 0) 1 else 0, hours = left)
+    }
+
+    klockDayOfMonth ?.let {
+        val left = it - current.dayOfMonth
+        current += DateTimeSpan(months = if (left < 0) 1 else 0, days = left)
+    }
+
+    month ?.let {
+        val left = it - current.month0
+        current += DateTimeSpan(months = if (left < 0) 1 else 0, days = left)
+    }
+
+    return current
+}

src/commonMain/kotlin/com/github/insanusmokrassar/krontab/parts/CronDateTime.kt

@@ -1,42 +0,0 @@
-package com.github.insanusmokrassar.krontab.parts
-
-import com.soywiz.klock.*
-
-data class CronDateTime(
-    val month: Byte? = null,
-    val dayOfMonth: Byte? = null,
-    val hour: Byte? = null,
-    val minute: Byte? = null,
-    val second: Byte? = null
-)
-
-fun CronDateTime.toNearDateTime(relativelyTo: DateTime = DateTime.now()): DateTime {
-    var current = relativelyTo
-
-    second ?.let {
-        val left = it - current.seconds
-        current += DateTimeSpan(minutes = if (left < 0) 1 else 0, seconds = left)
-    }
-
-    minute ?.let {
-        val left = it - current.minutes
-        current += DateTimeSpan(hours = if (left < 0) 1 else 0, minutes = left)
-    }
-
-    hour ?.let {
-        val left = it - current.hours
-        current += DateTimeSpan(days = if (left < 0) 1 else 0, hours = left)
-    }
-
-    dayOfMonth ?.let {
-        val left = it - current.dayOfMonth
-        current += DateTimeSpan(months = if (left < 0) 1 else 0, days = left)
-    }
-
-    month ?.let {
-        val left = it - current.month0
-        current += DateTimeSpan(months = if (left < 0) 1 else 0, days = left)
-    }
-
-    return current
-}

src/commonMain/kotlin/com/github/insanusmokrassar/krontab/utils/Data.kt

@@ -0,0 +1,4 @@
+package com.github.insanusmokrassar.krontab.utils
+
+internal fun Int.clamp(min: Int, max: Int): Int = if (this < min) min else if (this > max) max else this
+internal fun Int.clamp(range: IntRange): Int = clamp(range.first, range.last)