Foxy.Core

Foxy.Core provides extensions and useful helpers functions that rely only on .net standard 2.0.

Content (Namespaces)

Cleanup

This namespace contains a helpers for executing disposing tasks easily. Main class is DisposableContainerExtensions. You can put multiple object with IDisposabe interface in it. The Dispose calls are in separate try catch block so an exception won't stop the disposition of other resources when one element is failed. If you want to react for on an exception you can in the DisposeFailed event.

Nowadays usually the dependency injection container handles the disposition but still there use cases when this is usefull. For example the event handler unsubscription.

Examples

    public class Foo : IDisposable
    {
        private readonly DisposableContainer _disposable;
        private readonly Baz _baz;
        public Foo()
        {
            _disposable = new DisposableContainer();

            // Adding a disposabe object.
            _baz = _disposable.AddManagedResource(new Baz());

            // Adding an event. This prevent a memory leak. object is the event argument type.
            _disposable.AddEventSubscription<object>(typeof(Baz), nameof(Baz.StaticEventHandler), EventHandler);

            // Adding an arbitary cleanup action.
            _disposable.AddCleanupAction(SomeCleanup);
        }

        private void EventHandler(object obj) { }

        public void Dispose()
        {
            _disposable.Dispose();
        }
    }

Collections

This namespace contains some usefull extensions for the System.Collections.Generic namespace.

AddRange

Sometimes I work with ICollection or it's derivative but I still would like to use AddRange from the List<T>. This extension comes to help.

    ICollection<Element> collection = GetSomeCollection();
    IEnumerable<Element> newValues = CreateNewValues();

    collection.AddRange(newValues);

AddElements

Adds several element to a collection.

    ICollection<Element> collection = GetSomeCollection();

    collection.AddElements(element1, element2);

FindAndRemove

This methods find an element in the list and if found removes it. A commonly used pattern by me when working with a list of ORM records is take a copy of the target list, and for every element from the source I try to find in the target. If it is not there I add to the target, if there I take out from the copy and I update. The remaining should be deleted. It looks like this:

    var targetList = element.Items.ToList();
    foreach(var sourceItem in source) {
        var targetItem = targetList.FindAndRemove(item => item.Key == sourceItem.Key);
        if(targetItem == null) {
            element.Items.Add(CreateElement(sourceItem));
        } else {
            UpdateElement(targetItem, sourceItem);
        }
    }
    element.Items.RemoveAll(targetList);

ToChunks

Sometimes it is necessary to process a very large list but you can process only a small batch at once. This extension breaks the large list to fixed size.

    var largeEnumerator = GetData();
    foreach(var chunk in largeEnumerator.ToChunks(size)) {
        ProcessChunk(chunk);
    }

SortByKey

If you want to sort a List<T> or an Array<T> by a key element this extension simplifies it.

    List<Element> list = GetUnsortedList();
    list.SortByKey(element => element.Key);

Linq

This namespace contains a left join for linq. This method extracts the common pattern that is used for left joins and usually recognized by ORMs so it can be used in database translated queries also. I use navigation properties to express left joins mostly but sometimes I need queries like this and it is more readable to write a LeftJoin than the original pattern.

The original left join pattern looks like this:

    var result = outer.GroupJoin(inner, outer => outer.Key, inner.Key, (inner, outer) => new { inner, outer })
        .SelectMany(groups => groups.outer.DefaultIfEmpty(), (joined, groupElement) => new { inner = joined.inner, outer = groupElement });

With the extension you can write like the regular join:

    var result = outer.LeftJoin(inner, outer => outer.Key, inner => inner.Key, (inner, outer) => new { inner, outer });

Text

This namespace contains a natural string comparer. Natural string comparison in short means when you compare strings you treat digits as numbers if both string contains digit in the same position. There are several implementation on the stackoverflow and in the github so when I decided to write an own implementation I set the following goals:

• It has to be pure managed implementation. No native call.
• It has to be the fastest implementation in the .net world. (Sorting is process consuming)
• It has to have the same interface as the original StringComparer so it can be swapped where needed.
• Have some fun and learn new things while implementiing it. :)

I think I managed to statisfy all three goal so enjoy the result.

Example

    var list = GetFiles();
    list.Sort(NaturalStringComparer.OrdinalIgnoreCase);

Result:

    File 2.txt
    File 7.txt
    File 24.txt
    File 25.txt
    ...

Some note on the implementation

As best practices tells you should use Ordinal or OrdinalIgnoreCase whenever possible. In my implementation I use caching for culture specific comparisons which eats lots of memory (128kb per culture).

I focused only on 64 bit processors. Based on the StringComparer the 32 bit version should have a little bit different implementation. I don't know if it is important since almost every processor is 64 bit nowadays.

My original intent was to help optimize the NaturalSort.Extension package since that is the most popular natural sort package but in the end I didn't like it's interface and I completely reworked the implementation anyway. In the end I used it as a comparison.

Perfomance tests

I compared my implementation against The StringComparer (although it is not natural string comparer), NaturalSort.Extension, and StrCmpLogicalW native method.

BenchmarkDotNet=v0.12.1, OS=Windows 10.0.19041.572 (2004/?/20H1)
AMD Ryzen 5 2600, 1 CPU, 12 logical and 6 physical cores
.NET Core SDK=3.1.403
  [Host]     : .NET Core 3.1.9 (CoreCLR 4.700.20.47201, CoreFX 4.700.20.47203), X64 RyuJIT
  Job-TPQDPV : .NET Core 3.1.9 (CoreCLR 4.700.20.47201, CoreFX 4.700.20.47203), X64 RyuJIT

OutlierMode=RemoveAll  

Comparing two long text with invariant culture

• OrdinalPerf -> "Lorem ipsum dolor sit amet, consectetur adipiscing elit. 2 a" vs "Lorem ipsum dolor sit amet, consectetur adipiscing elit. 10 a"
• ToUpperPerf -> "LOREM IPSUM DOLOR SIT AMET, CONSECTETUR ADIPISCING ELIT. 2 A" vs "Lorem ipsum dolor sit amet, consectetur adipiscing elit. 10 a"

Method	Pairs	Mean	Error	StdDev	Ratio	Rank
NaturalStringComparer	OrdinalPerf	21.72 ns	0.233 ns	0.206 ns	0.009	1
NaturalSortExtension	OrdinalPerf	2,216.32 ns	7.710 ns	6.835 ns	0.961	3
PInvokeComparer	OrdinalPerf	2,306.10 ns	8.937 ns	8.360 ns	1.000	4
StringComparer	OrdinalPerf	109.82 ns	0.521 ns	0.435 ns	0.048	2
NaturalStringComparer	ToUpperPerf	166.78 ns	1.390 ns	1.300 ns	0.07	1
NaturalSortExtension	ToUpperPerf	2,509.88 ns	12.436 ns	9.709 ns	1.09	4
PInvokeComparer	ToUpperPerf	2,308.19 ns	12.155 ns	10.150 ns	1.00	3
StringComparer	ToUpperPerf	243.01 ns	1.770 ns	1.656 ns	0.11	2

Sorting a list of text with invariant culture.

Method	Mean	Error	StdDev	Ratio	Rank
NaturalStringComparer	7.903 ms	0.0314 ms	0.0294 ms	0.15	1
NaturalSortExtension	64.938 ms	0.2719 ms	0.2544 ms	1.21	4
PInvokeComparer	53.483 ms	0.1309 ms	0.1161 ms	1.00	3
StringComparer	17.276 ms	0.0960 ms	0.0898 ms	0.32	2

Comparing two long text with ordinal

• OrdinalPerf -> "Lorem ipsum dolor sit amet, consectetur adipiscing elit. 2 a" vs "Lorem ipsum dolor sit amet, consectetur adipiscing elit. 10 a"
• ToUpperPerf -> "LOREM IPSUM DOLOR SIT AMET, CONSECTETUR ADIPISCING ELIT. 2 A" vs "Lorem ipsum dolor sit amet, consectetur adipiscing elit. 10 a"

Method	Pairs	Mean	Error	StdDev	Ratio	Rank
NaturalStringComparer	OrdinalPerf	22.863 ns	0.2800 ns	0.2619 ns	0.010	2
NaturalSortExtension	OrdinalPerf	981.308 ns	5.6031 ns	5.2411 ns	0.424	3
PInvokeComparer	OrdinalPerf	2,310.651 ns	14.8619 ns	13.1746 ns	1.000	4
StringComparer	OrdinalPerf	11.285 ns	0.0467 ns	0.0364 ns	0.005	1
NaturalStringComparer	ToUpperPerf	6.796 ns	0.0302 ns	0.0252 ns	0.003	2
NaturalSortExtension	ToUpperPerf	69.479 ns	0.5270 ns	0.4929 ns	0.030	3
PInvokeComparer	ToUpperPerf	2,351.548 ns	7.8520 ns	7.3448 ns	1.000	4
StringComparer	ToUpperPerf	3.184 ns	0.0466 ns	0.0413 ns	0.001	1

Sorting a list of text with ordinal.

Method	Mean	Error	StdDev	Ratio	Rank
NaturalStringComparer	5.597 ms	0.0224 ms	0.0175 ms	0.11	2
NaturalSortExtension	23.090 ms	0.0263 ms	0.0220 ms	0.44	3
PInvokeComparer	52.110 ms	0.3530 ms	0.2947 ms	1.00	4
StringComparer	4.262 ms	0.0147 ms	0.0122 ms	0.08	1

Thanks

I say a huge thanks for the .net development team since the most impactful parts of the natural string comparer solution comes from the original StringComparer implementation. Also thanks for the documentation comments in the .net ecosystem. It helped me out to write my own documentation that hopefully have sense.

I also say thank you for my colleague Horia who designed the foxy icon.