org.sincron.atomic.package.scala Maven / Gradle / Ivy
/*
* Copyright (c) 2016 by its authors. Some rights reserved.
* See the project homepage at: https://sincron.org
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.sincron
import org.sincron.atomic.PaddingStrategy._
import org.sincron.atomic.boxes.BoxPaddingStrategy
/** A small toolkit of classes that support compare-and-swap semantics for safe mutation of variables.
*
* On top of the JVM, this means dealing with lock-free thread-safe programming. Also works on top of Javascript,
* with Scala.js, for API compatibility purposes and because it's a useful way to box a value.
*
* The backbone of Atomic references is this method:
* {{{
* def compareAndSet(expect: T, update: T): Boolean
* }}}
*
* This method atomically sets a variable to the `update` value if it currently holds
* the `expect` value, reporting `true` on success or `false` on failure. The classes in this package
* also contain methods to get and unconditionally set values.
*
* Building a reference is easy with the provided constructor, which will automatically return the
* most specific type needed (in the following sample, that's an `AtomicDouble`, inheriting from `AtomicNumber[T]`):
* {{{
* val atomicNumber = Atomic(12.2)
*
* atomicNumber.incrementAndGet()
* // => 13.2
* }}}
*
* These also provide useful helpers for atomically mutating of values
* (i.e. `transform`, `transformAndGet`, `getAndTransform`, etc...) or of numbers of any kind
* (`incrementAndGet`, `getAndAdd`, etc...).
*/
package object atomic {
/** Internal utility for converting between padding strategy representations. */
private[sincron] def boxStrategyToPaddingStrategy(s: PaddingStrategy): BoxPaddingStrategy =
s match {
case NoPadding =>
BoxPaddingStrategy.NO_PADDING
case Left64 =>
BoxPaddingStrategy.LEFT_64
case Right64 =>
BoxPaddingStrategy.RIGHT_64
case LeftRight128 =>
BoxPaddingStrategy.LEFT_RIGHT_128
case Left128 =>
BoxPaddingStrategy.LEFT_128
case Right128 =>
BoxPaddingStrategy.RIGHT_128
case LeftRight256 =>
BoxPaddingStrategy.LEFT_RIGHT_256
}
}