Greatly improve cable network segment slicing and splicing

because LinkedHashSet uses linked list, while ObjectLinkedOpenHashSet use sequential array of keys

src/main/kotlin/ru/dbotthepony/mc/otm/block/entity/cable/EnergyCableGraph.kt

@@ -1,11 +1,8 @@
 package ru.dbotthepony.mc.otm.block.entity.cable
 
-import it.unimi.dsi.fastutil.ints.IntLists
-import it.unimi.dsi.fastutil.objects.ObjectLinkedOpenHashSet
-import it.unimi.dsi.fastutil.objects.ObjectOpenHashSet
 import it.unimi.dsi.fastutil.objects.Reference2ObjectOpenHashMap
 import it.unimi.dsi.fastutil.objects.ReferenceArraySet
-import it.unimi.dsi.fastutil.objects.ReferenceOpenHashSet
+import it.unimi.dsi.fastutil.objects.ReferenceLinkedOpenHashSet
 import net.minecraft.core.BlockPos
 import org.apache.logging.log4j.LogManager
 import ru.dbotthepony.mc.otm.SERVER_IS_LIVE
@@ -19,6 +16,7 @@ import ru.dbotthepony.mc.otm.onceServer
 import java.util.*
 import kotlin.collections.ArrayList
 import kotlin.collections.HashSet
+import kotlin.collections.LinkedHashSet
 import kotlin.math.ln
 
 class EnergyCableGraph : GraphNodeList<EnergyCableBlockEntity.Node, EnergyCableGraph>() {
@@ -69,7 +67,7 @@ class EnergyCableGraph : GraphNodeList<EnergyCableBlockEntity.Node, EnergyCableG
 	}
 
 	class SegmentPath(private val a: BlockPos, private val b: BlockPos) {
-		val segments = ObjectLinkedOpenHashSet<Segment>()
+		val segments = LinkedHashSet<Segment>()
 		private var shortCircuit = false
 		private var lastTickTransfers = 0
 		private var lastTick = 0
@@ -134,13 +132,25 @@ class EnergyCableGraph : GraphNodeList<EnergyCableBlockEntity.Node, EnergyCableG
 			nodes.add(node)
 		}
 
-		private val nodes = ObjectLinkedOpenHashSet<EnergyCableBlockEntity.Node>()
-		private val paths = ReferenceOpenHashSet<SegmentPath>()
+		private val nodes = LinkedHashSet<EnergyCableBlockEntity.Node>()
+		private var paths = ReferenceLinkedOpenHashSet<SegmentPath>()
 
 		operator fun contains(node: EnergyCableBlockEntity.Node): Boolean {
 			return node in nodes
 		}
 
+		fun missingNodes(from: Collection<EnergyCableBlockEntity.Node>): List<EnergyCableBlockEntity.Node> {
+			val missing = ArrayList<EnergyCableBlockEntity.Node>()
+
+			this.nodes.forEach {
+				if (it !in from) {
+					missing.add(it)
+				}
+			}
+
+			return missing
+		}
+
 		var throughput = Decimal.ZERO
 			private set
 
@@ -284,8 +294,9 @@ class EnergyCableGraph : GraphNodeList<EnergyCableBlockEntity.Node, EnergyCableG
 		}
 
 		fun add(path: SegmentPath) {
-			check(paths.add(path)) { "Path $path shouldn't contain $this" }
-			check(path.segments.add(this)) { "Path set and Segment disagree whenever $this is absent from $path" }
+			if (paths.add(path)) {
+				check(path.segments.add(this)) { "Path set and Segment disagree whenever $this is absent from $path" }
+			}
 		}
 
 		fun remove(path: SegmentPath) {
@@ -295,23 +306,23 @@ class EnergyCableGraph : GraphNodeList<EnergyCableBlockEntity.Node, EnergyCableG
 
 		// breaks "instant snapshots" of segments atm
 		// shouldn't cause major gameplay issues though
-		fun split(): List<Segment> {
-			if (nodes.isEmpty()) {
-				throw IllegalStateException("Empty segment somehow?")
-			} else if (nodes.size == 1) {
+		fun split(nodes: Collection<EnergyCableBlockEntity.Node>): List<Segment> {
+			for (node in nodes)
+				require(node in this.nodes) { "$node does not belong to $this" }
+
+			if (this.nodes.size == 1) {
 				return listOf(this)
 			} else {
-				lastPoweredStatus = 0
-				val list = ArrayList(nodes)
-				val itr = list.iterator()
-				itr.next()
 				val result = ArrayList<Segment>()
 				result.add(this)
 
-				for (v in itr) {
+				for (v in nodes) {
 					v.segment = Segment()
+					v.segment.throughput = v.energyThroughput
+					v.segment.throughputKnown = true
 					v.segment.transferredLastTick = transferredLastTick
-					v.segment.paths.addAll(paths)
+					v.segment.lastPoweredStatus = lastPoweredStatus
+					v.segment.paths = paths.clone()
 					paths.forEach { it.segments.add(v.segment) }
 					result.add(v.segment)
 				}
@@ -391,7 +402,7 @@ class EnergyCableGraph : GraphNodeList<EnergyCableBlockEntity.Node, EnergyCableG
 
 			if (first.node === b) {
 				// solution found
-				val solution = ArrayList<EnergyCableBlockEntity.Node>()
+				val solution = LinkedHashSet<EnergyCableBlockEntity.Node>()
 
 				var last = first.parent
 				solution.add(first.node)
@@ -402,10 +413,23 @@ class EnergyCableGraph : GraphNodeList<EnergyCableBlockEntity.Node, EnergyCableG
 				}
 
 				val touchedSegments = ReferenceArraySet<Segment>()
-				solution.forEach { touchedSegments.addAll(it.segment.split()) }
+
+				for (it in solution) {
+					if (it.segment in touchedSegments)
+						continue
+
+					val diff = it.segment.missingNodes(solution)
+
+					// segment satisfies new constraints
+					if (diff.isEmpty()) {
+						touchedSegments.add(it.segment)
+					} else {
+						touchedSegments.addAll(it.segment.split(diff))
+					}
+				}
+
 				val path = SegmentPath(a.blockEntity.blockPos, b.blockEntity.blockPos)
 				solution.forEach { it.segment.add(path) }
-
 				touchedSegments.forEach { it.tryCombine(touchedSegments) }
 
 				return path