| /* |
| * Copyright 2010-2018 JetBrains s.r.o. and Kotlin Programming Language contributors. |
| * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file. |
| */ |
| |
| @file:UseExperimental(ExperimentalUnsignedTypes::class) |
| package kotlin.internal |
| |
| // (a - b) mod c |
| private fun differenceModulo(a: UInt, b: UInt, c: UInt): UInt { |
| val ac = a % c |
| val bc = b % c |
| return if (ac >= bc) ac - bc else ac - bc + c |
| } |
| |
| private fun differenceModulo(a: ULong, b: ULong, c: ULong): ULong { |
| val ac = a % c |
| val bc = b % c |
| return if (ac >= bc) ac - bc else ac - bc + c |
| } |
| |
| /** |
| * Calculates the final element of a bounded arithmetic progression, i.e. the last element of the progression which is in the range |
| * from [start] to [end] in case of a positive [step], or from [end] to [start] in case of a negative |
| * [step]. |
| * |
| * No validation on passed parameters is performed. The given parameters should satisfy the condition: |
| * |
| * - either `step > 0` and `start <= end`, |
| * - or `step < 0` and `start >= end`. |
| * |
| * @param start first element of the progression |
| * @param end ending bound for the progression |
| * @param step increment, or difference of successive elements in the progression |
| * @return the final element of the progression |
| * @suppress |
| */ |
| @PublishedApi |
| @SinceKotlin("1.3") |
| internal fun getProgressionLastElement(start: UInt, end: UInt, step: Int): UInt = when { |
| step > 0 -> if (start >= end) end else end - differenceModulo(end, start, step.toUInt()) |
| step < 0 -> if (start <= end) end else end + differenceModulo(start, end, (-step).toUInt()) |
| else -> throw kotlin.IllegalArgumentException("Step is zero.") |
| } |
| |
| /** |
| * Calculates the final element of a bounded arithmetic progression, i.e. the last element of the progression which is in the range |
| * from [start] to [end] in case of a positive [step], or from [end] to [start] in case of a negative |
| * [step]. |
| * |
| * No validation on passed parameters is performed. The given parameters should satisfy the condition: |
| * |
| * - either `step > 0` and `start <= end`, |
| * - or `step < 0` and `start >= end`. |
| * |
| * @param start first element of the progression |
| * @param end ending bound for the progression |
| * @param step increment, or difference of successive elements in the progression |
| * @return the final element of the progression |
| * @suppress |
| */ |
| @PublishedApi |
| @SinceKotlin("1.3") |
| internal fun getProgressionLastElement(start: ULong, end: ULong, step: Long): ULong = when { |
| step > 0 -> if (start >= end) end else end - differenceModulo(end, start, step.toULong()) |
| step < 0 -> if (start <= end) end else end + differenceModulo(start, end, (-step).toULong()) |
| else -> throw kotlin.IllegalArgumentException("Step is zero.") |
| } |