ArrayBuffer

Just use Span if you can. I couldn't.

History

Here's some history; I wanted to get rid of codes like this:

list.Add("aaa");list.Add("bbb");list.Add("ccc");if(x){list.Add("ddd");list.Add("eee");}else{list.Add("fff");list.Add("ggg");list.Add("hhh");}

So I first tried doing something like this:

varlist=newList<string>{"aaa","bbb","ccc",};if(x){varadditions=new[]{"ddd","eee",};list.AddRange(additions);}else{varadditions=new[]{"fff","ggg","hhh",};list.AddRange(additions);}

Which made it look cleaner, but I wasn't so happy about making so many arrays just for the sake of making the code look cleaner.

ArrayBuffer makes the code look like this:

varbuffer=newArrayBuffer<string>(3);varlist=newList<string>();// Yay! Local functions!voidAddRange(ArrayBuffer<string>.Spanspan){using(span)list.AddRange(span);}AddRange(newArrayBuffer<string>.Span(buffer,3){"aaa","bbb","ccc",});if(x){AddRange(newArrayBuffer<string>.Span(buffer,2){"ddd","eee",});}else{AddRange(newArrayBuffer<string>.Span(buffer,3){"fff","ggg","hhh",});}

Which is still readable, and no more multiple allocations. Just keep the initial size the max size you need (new ArrayBuffer<string>(3)).

Usage

1. Create a buffer first.

varbuffer=newArrayBuffer<string>(10);

2. There are 2 ways you can create buffers.

   • Use Take.

   varspan=buffer.Take(10);

   • Create a new Span

   varspan=newArrayBuffer<string>.Span(buffer,10);

   • These are both essentially the same (Take just calls new Span) but creating a Span will give you the capability to use the Collection Initializer.

3. Add items like normal arrays.

span[0]="hello";

4. When you're done, call Return. After calling Return, you will no longer be able to access the items in the Span. Although accessing them will not crash your program, you should just put the Span in a using block.

span.Return();// betterusing(varspan=buffer.Take(10)){
...}

Notice

Do not use the Add method! The Add method is only there for using Collection Initializers. You will get an exception if you try to use Add.

Benchmark

Seems like using pure arrays might be better. meh.

Method	Mean	Error	StdDev	Gen 0	Gen 1	Gen 2	Allocated
NormalListAndAdd	83.12 ns	1.614 ns	1.585 ns	0.1913	-	-	184 B
ListAndArray	232.13 ns	3.011 ns	2.669 ns	0.3245	-	-	312 B
ListAndArrayBuffer	604.80 ns	9.204 ns	8.159 ns	0.6399	-	-	616 B
ListAndArrayBufferWithLocalFunction	653.07 ns	14.461 ns	13.527 ns	0.6399	-	-	616 B