public void Test_1000000_array_copy_time_classes_should_be_faster()
{
var testSize = 1000000;
var structArray = new ValueStruct[testSize];
for (var i = 0; i < testSize; i++)
{
structArray[i] = new ValueStruct { AProperty = 1, AField = 1 };
}
var start = DateTime.Now;
var copied = new ValueStruct[testSize];
structArray.CopyTo(copied, 0);
var structsEnded = (DateTime.Now - start).TotalMilliseconds;
var classArray = new ReferenceClass[testSize];
for (var i = 0; i < testSize; i++)
{
classArray[i] = new ReferenceClass { AProperty = 1, AField = 1 };
}
start = DateTime.Now;
var copied2 = new ReferenceClass[testSize];
classArray.CopyTo(copied2, 0);
var classesEnded = (DateTime.Now - start).TotalMilliseconds;
Console.WriteLine($"Classes copied in:{classesEnded}ms");
Console.WriteLine($"Structs copied in:{structsEnded}ms");
Assert.IsTrue(classesEnded < structsEnded);
}
public void Passed_ByRef_instance_properties_can_be_mutated()
{
var referenceClass = new ReferenceClass();
Assert.AreEqual(0, referenceClass.AProperty);
ReferenceClassMutator.ChangeAProperty(ref referenceClass);
//Fields are updated as we're updating the instance passed in
Assert.AreEqual(1, referenceClass.AProperty);
}
public void Passed_ByVal_instance_properties_can_be_mutated()
{
var referenceClass = new ReferenceClass();
Assert.AreEqual(0, referenceClass.AProperty);
ReferenceClassMutator.ChangeAProperty(referenceClass);
//Because the instance copied is a reference type, all we've copied is it's pointers to instances of value types
//This means we end up sharing their pointers and updating them across both instances
Assert.AreEqual(1, referenceClass.AProperty);
}
public void Passed_ByVal_instance_cant_be_mutated()
{
var referenceClass = new ReferenceClass();
Assert.AreEqual(0, referenceClass.AField);
Assert.AreEqual(0, referenceClass.AProperty);
ReferenceClassMutator.ChangeTheInstanceOfReferenceClass(referenceClass);
//Changing the instance has no effect as the instance has been copied
Assert.AreEqual(0, referenceClass.AField);
Assert.AreEqual(0, referenceClass.AProperty);
}
public void Passed_ByRef_instance_can_be_mutated()
{
var referenceClass = new ReferenceClass();
Assert.AreEqual(0, referenceClass.AField);
Assert.AreEqual(0, referenceClass.AProperty);
ReferenceClassMutator.ChangeTheInstanceOfReferenceClass(ref referenceClass);
//Changing the instance means that the current instance is "updated"
Assert.AreEqual(1, referenceClass.AField);
Assert.AreEqual(1, referenceClass.AProperty);
}
public void Copied_classes_are_mutally_sharing_properties_or_fields()
{
var testSize = 1000000;
var classArray = new ReferenceClass[testSize];
for (var i = 0; i < testSize; i++)
{
classArray[i] = new ReferenceClass { AProperty = 1, AField = 1 };
}
var copied = new ReferenceClass[testSize];
classArray.CopyTo(copied, 0);
for (var i = 0; i < testSize; i++)
{
copied[i].AField = 0;
Assert.AreEqual(classArray[i].AField, copied[i].AField);
copied[i].AProperty = 0;
Assert.AreEqual(classArray[i].AProperty, copied[i].AProperty);
}
}
public void Test_1000000_instance_creation_time_structs_should_be_faster()
{
var testSize = 1000000;
var structArray = new ValueStruct[testSize];
var start = DateTime.Now;
for (var i = 0; i < testSize; i++)
{
structArray[i] = new ValueStruct {AProperty = 1, AField = 1};
}
var structsEnded = (DateTime.Now - start).TotalMilliseconds;
var classArray = new ReferenceClass[testSize];
start = DateTime.Now;
for (var i = 0; i < testSize; i++)
{
classArray[i] = new ReferenceClass { AProperty = 1, AField = 1 };
}
var classesEnded = (DateTime.Now - start).TotalMilliseconds;
Console.WriteLine($"Classes creation:{classesEnded}ms");
Console.WriteLine($"Structs creation:{structsEnded}ms");
Assert.IsTrue(classesEnded > structsEnded);
}
