103 lines
3.1 KiB
C#
103 lines
3.1 KiB
C#
// Licensed to the .NET Foundation under one or more agreements.
|
|
// The .NET Foundation licenses this file to you under the MIT license.
|
|
// See the LICENSE file in the project root for more information.
|
|
|
|
using System;
|
|
using System.Collections.Generic;
|
|
using System.ComponentModel;
|
|
using System.Runtime.CompilerServices;
|
|
|
|
namespace CommunityToolkit.HighPerformance.Enumerables;
|
|
|
|
/// <summary>
|
|
/// A <see langword="ref"/> <see langword="struct"/> that tokenizes a given <see cref="Span{T}"/> instance.
|
|
/// </summary>
|
|
/// <typeparam name="T">The type of items to enumerate.</typeparam>
|
|
[EditorBrowsable(EditorBrowsableState.Never)]
|
|
public ref struct SpanTokenizer<T>
|
|
where T : IEquatable<T>
|
|
{
|
|
/// <summary>
|
|
/// The source <see cref="Span{T}"/> instance.
|
|
/// </summary>
|
|
private readonly Span<T> span;
|
|
|
|
/// <summary>
|
|
/// The separator item to use.
|
|
/// </summary>
|
|
private readonly T separator;
|
|
|
|
/// <summary>
|
|
/// The current initial offset.
|
|
/// </summary>
|
|
private int start;
|
|
|
|
/// <summary>
|
|
/// The current final offset.
|
|
/// </summary>
|
|
private int end;
|
|
|
|
/// <summary>
|
|
/// Initializes a new instance of the <see cref="SpanTokenizer{T}"/> struct.
|
|
/// </summary>
|
|
/// <param name="span">The source <see cref="Span{T}"/> instance.</param>
|
|
/// <param name="separator">The separator item to use.</param>
|
|
[MethodImpl(MethodImplOptions.AggressiveInlining)]
|
|
public SpanTokenizer(Span<T> span, T separator)
|
|
{
|
|
this.span = span;
|
|
this.separator = separator;
|
|
this.start = 0;
|
|
this.end = -1;
|
|
}
|
|
|
|
/// <summary>
|
|
/// Implements the duck-typed <see cref="IEnumerable{T}.GetEnumerator"/> method.
|
|
/// </summary>
|
|
/// <returns>An <see cref="SpanTokenizer{T}"/> instance targeting the current <see cref="Span{T}"/> value.</returns>
|
|
[MethodImpl(MethodImplOptions.AggressiveInlining)]
|
|
public readonly SpanTokenizer<T> GetEnumerator() => this;
|
|
|
|
/// <summary>
|
|
/// Implements the duck-typed <see cref="System.Collections.IEnumerator.MoveNext"/> method.
|
|
/// </summary>
|
|
/// <returns><see langword="true"/> whether a new element is available, <see langword="false"/> otherwise</returns>
|
|
[MethodImpl(MethodImplOptions.AggressiveInlining)]
|
|
public bool MoveNext()
|
|
{
|
|
int newEnd = this.end + 1;
|
|
int length = this.span.Length;
|
|
|
|
// Additional check if the separator is not the last character
|
|
if (newEnd <= length)
|
|
{
|
|
this.start = newEnd;
|
|
|
|
int index = this.span.Slice(newEnd).IndexOf(this.separator);
|
|
|
|
// Extract the current subsequence
|
|
if (index >= 0)
|
|
{
|
|
this.end = newEnd + index;
|
|
|
|
return true;
|
|
}
|
|
|
|
this.end = length;
|
|
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
/// <summary>
|
|
/// Gets the duck-typed <see cref="IEnumerator{T}.Current"/> property.
|
|
/// </summary>
|
|
public readonly Span<T> Current
|
|
{
|
|
[MethodImpl(MethodImplOptions.AggressiveInlining)]
|
|
get => this.span.Slice(this.start, this.end - this.start);
|
|
}
|
|
}
|