commonMain.earth.worldwind.util.BasicPool.kt Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of worldwind-jvm Show documentation

The WorldWind Kotlin SDK (WWK) includes the library, examples and tutorials for building multiplatform 3D virtual globe applications for Android, Web and Java.

The newest version!

package earth.worldwind.util

import kotlin.math.max

@Suppress("UNCHECKED_CAST")
open class BasicPool: Pool {
    companion object {
        protected const val MIN_CAPACITY_INCREMENT = 12
    }

    protected var size = 0
    protected var entries = arrayOfNulls(size)

    override fun acquire(): T? {
        if (size > 0) {
            val last = --size
            val instance = entries[last]
            entries[last] = null
            return instance as T?
        }
        return null
    }

    override fun release(instance: T?) {
        // TODO reduce the pool size when excess entries may not be needed
        // TODO use a keep alive time to indicate how long to keep stale instances
        if (instance != null) {
            val capacity = entries.size
            if (capacity == size) {
                // increase the pool size by the larger of 50% or the minimum increment
                val increment = max(capacity shr 1, MIN_CAPACITY_INCREMENT)
                val newEntries = arrayOfNulls(capacity + increment)
                entries.copyInto(newEntries, 0, 0, capacity)
                entries = newEntries
            }
            entries[size++] = instance
        }
    }
}