Sequence.md

Sequence<T>

Sequence<T> is a builder for ReadOnlySequence<T>, which was popularized by the System.IO.Pipelines API. It can be used both to build and maintain sequences as they are read.

A Sequence<T> efficiently uses larger buffers to store many smaller writes. When a part of the sequence has been read, the buffers backing the read data are recycled for use later. This allows for a virtually alloc-free cycle of reading and writing.

Sample

The following sample demonstrates creating a sequence, and responding to reads by advancing to the position read.

var seq = new Sequence<char>();

var mem1 = seq.GetMemory(3);
mem1.Span[0] = 'a';
mem1.Span[1] = 'b';
seq.Advance(2);

var mem2 = seq.GetMemory(2);
mem2.Span[0] = 'c';
mem2.Span[1] = 'd';
seq.Advance(2);

ReadOnlySequence<T> ros = seq.AsReadOnlySequence;
Assert.Equal("abcd".ToCharArray(), ros.ToArray());

seq.AdvanceTo(ros.GetPosition(1));
ros = seq.AsReadOnlySequence;
Assert.Equal("bcd".ToCharArray(), ros.ToArray());