Make layout map actually immutable

- Also implement hashCode and equals on *ElementTypeImpl, Layout, and
Layout.Element

src/main/java/com/jozufozu/flywheel/impl/layout/LayoutImpl.java

@@ -1,6 +1,6 @@
 package com.jozufozu.flywheel.impl.layout;
 
-import java.util.HashMap;
+import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 
@@ -9,20 +9,27 @@ import org.jetbrains.annotations.Unmodifiable;
 import com.jozufozu.flywheel.api.layout.ElementType;
 import com.jozufozu.flywheel.api.layout.Layout;
 
+import it.unimi.dsi.fastutil.objects.Object2ObjectOpenHashMap;
+
 final class LayoutImpl implements Layout {
+	@Unmodifiable
 	private final List<Element> elements;
+	@Unmodifiable
 	private final Map<String, ElementType> map;
 	private final int byteSize;
 
-	LayoutImpl(List<Element> elements) {
+	LayoutImpl(@Unmodifiable List<Element> elements) {
 		this.elements = elements;
 
-		map = new HashMap<>();
+		Object2ObjectOpenHashMap<String, ElementType> map = new Object2ObjectOpenHashMap<>();
 		int byteSize = 0;
 		for (Element element : this.elements) {
 			map.put(element.name(), element.type());
 			byteSize += element.type().byteSize();
 		}
+		map.trim();
+
+		this.map = Collections.unmodifiableMap(map);
 		this.byteSize = byteSize;
 	}
 
@@ -43,6 +50,52 @@ final class LayoutImpl implements Layout {
 		return byteSize;
 	}
 
+	@Override
+	public int hashCode() {
+		final int prime = 31;
+		int result = 1;
+		result = prime * result + elements.hashCode();
+		return result;
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj) {
+			return true;
+		}
+		if (obj == null) {
+			return false;
+		}
+		if (getClass() != obj.getClass()) {
+			return false;
+		}
+		LayoutImpl other = (LayoutImpl) obj;
+		return elements.equals(other.elements);
+	}
+
 	record ElementImpl(String name, ElementType type) implements Element {
+		@Override
+		public int hashCode() {
+			final int prime = 31;
+			int result = 1;
+			result = prime * result + name.hashCode();
+			result = prime * result + type.hashCode();
+			return result;
+		}
+
+		@Override
+		public boolean equals(Object obj) {
+			if (this == obj) {
+				return true;
+			}
+			if (obj == null) {
+				return false;
+			}
+			if (getClass() != obj.getClass()) {
+				return false;
+			}
+			ElementImpl other = (ElementImpl) obj;
+			return name.equals(other.name) && type.equals(other.type);
+		}
 	}
 }

src/main/java/com/jozufozu/flywheel/impl/layout/MatrixElementTypeImpl.java

@@ -48,4 +48,29 @@ final class MatrixElementTypeImpl implements MatrixElementType {
 	public int byteSize() {
 		return byteSize;
 	}
+
+	@Override
+	public int hashCode() {
+		final int prime = 31;
+		int result = 1;
+		result = prime * result + repr.hashCode();
+		result = prime * result + rows;
+		result = prime * result + columns;
+		return result;
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj) {
+			return true;
+		}
+		if (obj == null) {
+			return false;
+		}
+		if (getClass() != obj.getClass()) {
+			return false;
+		}
+		MatrixElementTypeImpl other = (MatrixElementTypeImpl) obj;
+		return repr == other.repr && rows == other.rows && columns == other.columns;
+	}
 }

src/main/java/com/jozufozu/flywheel/impl/layout/ScalarElementTypeImpl.java

@@ -21,4 +21,27 @@ final class ScalarElementTypeImpl implements ScalarElementType {
 	public int byteSize() {
 		return byteSize;
 	}
+
+	@Override
+	public int hashCode() {
+		final int prime = 31;
+		int result = 1;
+		result = prime * result + repr.hashCode();
+		return result;
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj) {
+			return true;
+		}
+		if (obj == null) {
+			return false;
+		}
+		if (getClass() != obj.getClass()) {
+			return false;
+		}
+		ScalarElementTypeImpl other = (ScalarElementTypeImpl) obj;
+		return repr == other.repr;
+	}
 }

src/main/java/com/jozufozu/flywheel/impl/layout/VectorElementTypeImpl.java

@@ -36,4 +36,28 @@ final class VectorElementTypeImpl implements VectorElementType {
 	public int byteSize() {
 		return byteSize;
 	}
+
+	@Override
+	public int hashCode() {
+		final int prime = 31;
+		int result = 1;
+		result = prime * result + repr.hashCode();
+		result = prime * result + size;
+		return result;
+	}
+
+	@Override
+	public boolean equals(Object obj) {
+		if (this == obj) {
+			return true;
+		}
+		if (obj == null) {
+			return false;
+		}
+		if (getClass() != obj.getClass()) {
+			return false;
+		}
+		VectorElementTypeImpl other = (VectorElementTypeImpl) obj;
+		return repr == other.repr && size == other.size;
+	}
 }