59 lines
1.4 KiB
Swift
59 lines
1.4 KiB
Swift
//
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// HashingTests.swift
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// FirebladeECSTests
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//
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// Created by Christian Treffs on 16.10.17.
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//
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import Darwin
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import XCTest
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@testable import FirebladeECS
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class HashingTests: XCTestCase {
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func testCollisionsInCritialRange() {
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var hashSet: Set<Int> = Set<Int>()
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var range: CountableRange<EntityIdentifier> = 0 ..< 1_000_000
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let maxComponents: Int = 1000
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let components: [Int] = (0..<maxComponents).map { _ in makeComponent() }
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var index: Int = 0
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while let eId: EntityIdentifier = range.popLast() {
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let entityId: EntityIdentifier = eId
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let c = (index % maxComponents)
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index += 1
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let cH: ComponentTypeHash = components[c]
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let h: Int = EntityComponentHash.compose(entityId: entityId, componentTypeHash: cH)
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let (collisionFree, _) = hashSet.insert(h)
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XCTAssert(collisionFree)
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XCTAssert(EntityComponentHash.decompose(h, with: cH) == entityId)
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XCTAssert(EntityComponentHash.decompose(h, with: entityId) == cH)
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}
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}
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}
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// MARK: - helper
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extension HashingTests {
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func makeComponent() -> Int {
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let upperBound: Int = 44
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let high = UInt(arc4random()) << UInt(upperBound)
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let low = UInt(arc4random())
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assert(high.leadingZeroBitCount < 64-upperBound)
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assert(high.trailingZeroBitCount >= upperBound)
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assert(low.leadingZeroBitCount >= 32)
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assert(low.trailingZeroBitCount <= 32)
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let rand: UInt = high | low
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let cH = Int(bitPattern: rand)
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return cH
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}
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}
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