ValueCollections repository

[Joy-less]

I made a repository containing some more ref struct types you might be interested in.

Currently contains ValueList:

using ValueList<int> list = [];

for (int i = 0; i < 100; i++) {
    list.Add(i);
}

Console.WriteLine(string.Join(", ", list.ToList()));

Method	Mean	Error	StdDev	Gen0	Allocated
SmallListOfStruct	17.92 ns	0.122 ns	0.114 ns	0.0255	80 B
SmallValueListOfStruct	15.14 ns	0.050 ns	0.047 ns	-	-
SmallListOfClass	25.69 ns	0.077 ns	0.069 ns	0.0306	96 B
SmallValueListOfClass	18.36 ns	0.037 ns	0.033 ns	-	-
LargeListOfStruct	21,131.86 ns	119.642 ns	111.913 ns	41.6565	131400 B
LargeValueListOfStruct	7,454.80 ns	11.838 ns	10.494 ns	-	-

Link: https://github.com/Joy-less/ValueCollections

[linkdotnet]

Interesting. You might want to add a set of fixed SmallLists like: ThreeELementList that uses also the InlineArrayAttribute.
All in all - you should publish this as a Nuget packages as well if you see fit.

PS: I can't access your repository.

[Joy-less]

Apologies, I forgot to set it to public.
The small lists are an interesting idea. What kind of use case do you have in mind?

[linkdotnet]

Me, personally, non specific. But sometimes you are in need of those super specific collection types.
But they probably don’t make sense in an library.

that said, you already published a nuget package! Way to go!

[Joy-less]

I also added ValueHashSet which uses an ordered Span<T> synchronized with a Span<int> of hash codes, and does a binary search to find the insertion index.

using ValueHashSet<int> numbers = [];

for (int n = 1; n <= 5; n++) {
    numbers.Add(n);
}
for (int n = 3; n <= 7; n++) {
    numbers.Add(n);
}

Console.WriteLine(string.Join(", ", numbers.ToArray())); // 1, 2, 3, 4, 5, 6, 7

It's slower than HashSet but it's zero-allocation.

Method	Mean	Error	StdDev	Gen0	Gen1	Gen2	Allocated
SmallHashSetOfStruct	94.20 ns	0.662 ns	0.620 ns	0.1070	-	-	336 B
SmallValueHashSetOfStruct	137.42 ns	0.616 ns	0.577 ns	-	-	-	-
SmallHashSetOfClass	130.56 ns	0.762 ns	0.675 ns	0.1173	-	-	368 B
SmallValueListOfClass	163.45 ns	0.554 ns	0.518 ns	-	-	-	-
LargeHashSetOfStruct	186,989.50 ns	1,425.253 ns	1,263.450 ns	95.2148	95.2148	95.2148	538656 B
LargeValueHashSetOfStruct	227,245.29 ns	603.642 ns	564.647 ns	-	-	-	-

At some point I'll have to implement ValueDictionary... maybe some other time.

@linkdotnet One change I made that might be relevant to ValueStringBuilder is to move the buffer constructor to a static method.

// Old:
using ValueList<int> numbers = new(stackalloc int[32]);
// New:
using ValueList<int> numbers  = ValueList<int>.FromBuffer(stackalloc int[32]);

This could be changed in ValueStringBuilder to avoid confusion as well. The only problem is that it would be a major breaking change.

[Joy-less]

We do offer both versions, don't we?
1: Span: https://linkdotnet.github.io/StringBuilder/api/LinkDotNet.StringBuilder.ValueStringBuilder.html#LinkDotNet_StringBuilder_ValueStringBuilder__ctor_Span_System_Char__
2. ROS: https://linkdotnet.github.io/StringBuilder/api/LinkDotNet.StringBuilder.ValueStringBuilder.html#LinkDotNet_StringBuilder_ValueStringBuilder__ctor_ReadOnlySpan_System_Char__

Or do I miss something obvious here? :D

Yes, they are both offered, my point though is that someone might pass a Span expecting it to be appended as the initial characters, when really it is used as a buffer and the characters are ignored. For example, someone might pass an array of initial characters and not realise that it's used as a buffer, which doesn't append the characters; it treats it like it's zeroed-out.

[linkdotnet]

True that - we can add the OverloadResolutionPriorityAttribute to favor ReadOnlySpan over Span.a

[linkdotnet]

For example, someone might pass an array of initial characters and not realise that it's used as a buffer, which doesn't append the characters; it treats it like it's zeroed-out.

I gave that a second thought, and the only thing that happens is if you proactively create a Span<char>. Converting strings to a "span-like" objects will always result in ROS. Passing a writeable object to a method that expects something writeable - well - then we write :D

[Joy-less]

For example, someone might pass an array of initial characters and not realise that it's used as a buffer, which doesn't append the characters; it treats it like it's zeroed-out.

I gave that a second thought, and the only thing that happens is if you proactively create a Span<char>. Converting strings to a "span-like" objects will always result in ROS. Passing a writeable object to a method that expects something writeable - well - then we write :D

Might want to make it clear/bold in the doc comment to make sure.

[linkdotnet]

Oh good point. I might add this even to the XML-Doc.