[API Proposal]: Add SearchValues Overloads to SequenceReader

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Assessment

Difficulty
5/5
Estimated time
Over a week
Newbie friendliness
30/100
Issue type
Feature
Clarity
Mostly clear
Activity status
Stale
Tech stack
csharp
Domain
api, performance

Research direction

Start by reviewing SequenceReader’s existing delimiter overloads and the SearchValues API; the issue names no source files or tests. Done means resolving the generic versus extension-method design and implementing and testing the four proposed overloads.

Written by the indexing model from the issue text.

Description

api-suggestion area-System.Buffers
Background and motivation

SequenceReader has methods that take a ReadOnlySpan of delimiter values and advances/reads until finding one of those values. With SearchValues addition in .NET 8, a new set of overloads is a natural addition. They should be more performant than using the existing overloads while being no more complicated for developers to use (and even easier than using AdvancePastAny(T value0, T value1, T value2, T value3)).

API Proposal
namespace System.Buffers;

public ref struct SequenceReader<T>
{
    public bool TryAdvanceToAny(SearchValues<T> delimiters, bool advancePastDelimiter = true);
    public long AdvancePastAny(SearchValues<T> values);
    public bool TryReadToAny(out ReadOnlySequence<T> sequence, SearchValues<T> delimiters, bool advancePastDelimiter = true);
    public bool TryReadToAny(out ReadOnlySpan<T> span, SearchValues<T> delimiters, bool advancePastDelimiter = true);
}
API Usage
var newlines = SearchValues.Create("\r\n");
var sequenceReader = new SequenceReader(buffer);
sequenceReader.TryReadToAny(out ReadOnlySequence<T> line, newlines, false);
sequenceReader.AdvancePastAny(newlines);
Alternative Designs

We could also add extension methods for SequenceReader<char> and SearchValues<string>.

namespace System.Buffers;

public static class SequenceReaderExtensions
{
    public static bool TryAdvanceToAny(this SequenceReader<char> reader, SearchValues<string> delimiters, bool advancePastDelimiter = true);
    public static long AdvancePastAny(this SequenceReader<char> reader, SearchValues<string> values);
    public static bool TryReadToAny(this SequenceReader<char> reader, out ReadOnlySequence<char> sequence, SearchValues<string> delimiters, bool advancePastDelimiter = true);
    public static bool TryReadToAny(this SequenceReader<char> reader, out ReadOnlySpan<char> span, SearchValues<string> delimiters, bool advancePastDelimiter = true);
}
Risks

No response

Dominant language
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