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Code Issues

Un-nest SpanSplitEnumerator

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This commit is contained in:
Oliver Booth 2022-11-29 16:17:33 +00:00
parent f0781e5564
commit 2431a07a66
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GPG Key ID: 32A00B35503AF634
2 changed files with 87 additions and 86 deletions
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86
X10D/src/Collections/SpanExtensions.cs
View File

@ -111,90 +111,4 @@ public static class SpanExtensions
{
return new SpanSplitEnumerator<T>(source, delimiter);
}
/// <summary>
/// Enumerates the elements of a <see cref="ReadOnlySpan{T}" />.
/// </summary>
/// <typeparam name="T">The type of elements in the span.</typeparam>
public ref struct SpanSplitEnumerator<T> where T : struct, IEquatable<T>
{
private ReadOnlySpan<T> _source;
private readonly ReadOnlySpan<T> _delimiterSpan;
private readonly T _delimiter;
private readonly bool _usingSpanDelimiter;
/// <summary>
/// Initializes a new instance of the <see cref="SpanSplitEnumerator{T}" /> struct.
/// </summary>
/// <param name="source">The source span.</param>
/// <param name="delimiter">The delimiting span of elements.</param>
public SpanSplitEnumerator(in ReadOnlySpan<T> source, ReadOnlySpan<T> delimiter)
{
_usingSpanDelimiter = true;
_source = source;
_delimiter = default;
_delimiterSpan = delimiter;
Current = ReadOnlySpan<T>.Empty;
}
/// <summary>
/// Initializes a new instance of the <see cref="SpanSplitEnumerator{T}" /> struct.
/// </summary>
/// <param name="source">The source span.</param>
/// <param name="delimiter">The delimiting element.</param>
public SpanSplitEnumerator(in ReadOnlySpan<T> source, T delimiter)
{
_usingSpanDelimiter = false;
_source = source;
_delimiter = delimiter;
_delimiterSpan = ReadOnlySpan<T>.Empty;
Current = ReadOnlySpan<T>.Empty;
}
/// <summary>
/// Gets the element at the current position of the enumerator.
/// </summary>
/// <value>The element in the <see cref="ReadOnlySpan{T}" /> at the current position of the enumerator.</value>
public ReadOnlySpan<T> Current { get; private set; }
/// <summary>
/// Returns the current enumerator.
/// </summary>
/// <returns>The current instance of <see cref="SpanSplitEnumerator{T}" />.</returns>
/// <remarks>
/// This method exists to provide the ability to enumerate within a <c>foreach</c> loop. It should not be called
/// manually.
/// </remarks>
public readonly SpanSplitEnumerator<T> GetEnumerator()
{
return this;
}
/// <summary>
/// Advances the enumerator to the next element of the <see cref="ReadOnlySpan{T}" />.
/// </summary>
/// <returns>
/// <see langword="true" /> if the enumerator was successfully advanced to the next element; <see langword="false" />
/// if the enumerator has passed the end of the span.
/// </returns>
public bool MoveNext()
{
if (_source.Length == 0)
{
return false;
}
int index = _usingSpanDelimiter ? _source.IndexOf(_delimiterSpan) : _source.IndexOf(_delimiter);
if (index == -1)
{
Current = _source;
_source = ReadOnlySpan<T>.Empty;
return true;
}
Current = _source[..index];
_source = _source[(index + 1)..];
return true;
}
}
}

87
X10D/src/Collections/SpanSplitEnumerator.cs Normal file
View File

@ -0,0 +1,87 @@
namespace X10D.Collections;
/// <summary>
/// Enumerates the elements of a <see cref="ReadOnlySpan{T}" />.
/// </summary>
/// <typeparam name="T">The type of elements in the span.</typeparam>
public ref struct SpanSplitEnumerator<T> where T : struct, IEquatable<T>
{
private ReadOnlySpan<T> _source;
private readonly ReadOnlySpan<T> _delimiterSpan;
private readonly T _delimiter;
private readonly bool _usingSpanDelimiter;
/// <summary>
/// Initializes a new instance of the <see cref="SpanSplitEnumerator{T}" /> struct.
/// </summary>
/// <param name="source">The source span.</param>
/// <param name="delimiter">The delimiting span of elements.</param>
public SpanSplitEnumerator(in ReadOnlySpan<T> source, ReadOnlySpan<T> delimiter)
{
_usingSpanDelimiter = true;
_source = source;
_delimiter = default;
_delimiterSpan = delimiter;
Current = ReadOnlySpan<T>.Empty;
}
/// <summary>
/// Initializes a new instance of the <see cref="SpanSplitEnumerator{T}" /> struct.
/// </summary>
/// <param name="source">The source span.</param>
/// <param name="delimiter">The delimiting element.</param>
public SpanSplitEnumerator(in ReadOnlySpan<T> source, T delimiter)
{
_usingSpanDelimiter = false;
_source = source;
_delimiter = delimiter;
_delimiterSpan = ReadOnlySpan<T>.Empty;
Current = ReadOnlySpan<T>.Empty;
}
/// <summary>
/// Gets the element at the current position of the enumerator.
/// </summary>
/// <value>The element in the <see cref="ReadOnlySpan{T}" /> at the current position of the enumerator.</value>
public ReadOnlySpan<T> Current { get; private set; }
/// <summary>
/// Returns the current enumerator.
/// </summary>
/// <returns>The current instance of <see cref="SpanSplitEnumerator{T}" />.</returns>
/// <remarks>
/// This method exists to provide the ability to enumerate within a <c>foreach</c> loop. It should not be called
/// manually.
/// </remarks>
public readonly SpanSplitEnumerator<T> GetEnumerator()
{
return this;
}
/// <summary>
/// Advances the enumerator to the next element of the <see cref="ReadOnlySpan{T}" />.
/// </summary>
/// <returns>
/// <see langword="true" /> if the enumerator was successfully advanced to the next element; <see langword="false" />
/// if the enumerator has passed the end of the span.
/// </returns>
public bool MoveNext()
{
if (_source.Length == 0)
{
return false;
}
int index = _usingSpanDelimiter ? _source.IndexOf(_delimiterSpan) : _source.IndexOf(_delimiter);
if (index == -1)
{
Current = _source;
_source = ReadOnlySpan<T>.Empty;
return true;
}
Current = _source[..index];
_source = _source[(index + 1)..];
return true;
}
}