From 5a4f587b45d450f85f20d224281a7bc8884f1de0 Mon Sep 17 00:00:00 2001
From: Layomi Akinrinade <laakinri@microsoft.com>
Date: Thu, 11 Jun 2020 10:11:16 -0700
Subject: [PATCH] Revert "Added support for splitting on ReadOnlySpan<char>
 (#295)"

This reverts commit 78ed8e8ab18ae6a944e04aaa1c66928acef7da18.
---
 .../System.Memory/ref/System.Memory.cs        |   9 -
 .../tests/ReadOnlySpan/Split.char.cs          | 260 ------------------
 .../tests/System.Memory.Tests.csproj          |   1 -
 .../System.Private.CoreLib.Shared.projitems   |   2 -
 .../src/System/MemoryExtensions.Split.cs      |  38 ---
 .../src/System/SpanSplitEnumerator.T.cs       |  87 ------
 6 files changed, 397 deletions(-)
 delete mode 100644 src/libraries/System.Memory/tests/ReadOnlySpan/Split.char.cs
 delete mode 100644 src/libraries/System.Private.CoreLib/src/System/MemoryExtensions.Split.cs
 delete mode 100644 src/libraries/System.Private.CoreLib/src/System/SpanSplitEnumerator.T.cs

diff --git a/src/libraries/System.Memory/ref/System.Memory.cs b/src/libraries/System.Memory/ref/System.Memory.cs
index 18b6af79a9e9e..726e1066e62a0 100644
--- a/src/libraries/System.Memory/ref/System.Memory.cs
+++ b/src/libraries/System.Memory/ref/System.Memory.cs
@@ -91,9 +91,6 @@ public static void Sort<T>(this System.Span<T> span, System.Comparison<T> compar
         public static void Sort<TKey, TValue>(this System.Span<TKey> keys, System.Span<TValue> items) { }
         public static void Sort<TKey, TValue, TComparer>(this System.Span<TKey> keys, System.Span<TValue> items, TComparer comparer) where TComparer : System.Collections.Generic.IComparer<TKey>? { }
         public static void Sort<TKey, TValue>(this System.Span<TKey> keys, System.Span<TValue> items, System.Comparison<TKey> comparison) { }
-        public static System.SpanSplitEnumerator<char> Split(this System.ReadOnlySpan<char> span) { throw null; }
-        public static System.SpanSplitEnumerator<char> Split(this System.ReadOnlySpan<char> span, char separator) { throw null; }
-        public static System.SpanSplitEnumerator<char> Split(this System.ReadOnlySpan<char> span, string separator) { throw null; }
         public static bool StartsWith(this System.ReadOnlySpan<char> span, System.ReadOnlySpan<char> value, System.StringComparison comparisonType) { throw null; }
         public static bool StartsWith<T>(this System.ReadOnlySpan<T> span, System.ReadOnlySpan<T> value) where T : System.IEquatable<T> { throw null; }
         public static bool StartsWith<T>(this System.Span<T> span, System.ReadOnlySpan<T> value) where T : System.IEquatable<T> { throw null; }
@@ -159,12 +156,6 @@ public static void Sort<TKey, TValue>(this System.Span<TKey> keys, System.Span<T
         [System.ComponentModel.EditorBrowsableAttribute(System.ComponentModel.EditorBrowsableState.Never)]
         public object? GetObject() { throw null; }
     }
-    public ref struct SpanSplitEnumerator<T> where T : System.IEquatable<T>
-    {
-        public System.SpanSplitEnumerator<T> GetEnumerator() { throw null; }
-        public readonly System.Range Current { get { throw null; } }
-        public bool MoveNext() { throw null; }
-    }
 }
 namespace System.Buffers
 {
diff --git a/src/libraries/System.Memory/tests/ReadOnlySpan/Split.char.cs b/src/libraries/System.Memory/tests/ReadOnlySpan/Split.char.cs
deleted file mode 100644
index 10a832270163f..0000000000000
--- a/src/libraries/System.Memory/tests/ReadOnlySpan/Split.char.cs
+++ /dev/null
@@ -1,260 +0,0 @@
-// 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.Linq;
-using Xunit;
-
-namespace System.SpanTests
-{
-    public static partial class ReadOnlySpanTests
-    {
-        [Fact]
-        public static void SplitNoMatchSingleResult()
-        {
-            ReadOnlySpan<char> value = "a b";
-
-            string expected = value.ToString();
-            var enumerator = value.Split(',');
-            Assert.True(enumerator.MoveNext());
-            Assert.Equal(expected, value[enumerator.Current].ToString());
-        }
-
-        [Fact]
-        public static void DefaultSpanSplitEnumeratorBehavior()
-        {
-            var charSpanEnumerator = new SpanSplitEnumerator<string>();
-            Assert.Equal(new Range(0, 0), charSpanEnumerator.Current);
-            Assert.False(charSpanEnumerator.MoveNext());
-
-            // Implicit DoesNotThrow assertion
-            charSpanEnumerator.GetEnumerator();
-
-            var stringSpanEnumerator = new SpanSplitEnumerator<string>();
-            Assert.Equal(new Range(0, 0), stringSpanEnumerator.Current);
-            Assert.False(stringSpanEnumerator.MoveNext());
-            stringSpanEnumerator.GetEnumerator();
-        }
-
-        [Fact]
-        public static void ValidateArguments_OverloadWithoutSeparator()
-        {
-            ReadOnlySpan<char> buffer = default;
-
-            SpanSplitEnumerator<char>  enumerator = buffer.Split();
-            Assert.True(enumerator.MoveNext());
-            Assert.Equal(new Range(0, 0), enumerator.Current);
-            Assert.False(enumerator.MoveNext());
-
-            buffer = "";
-            enumerator = buffer.Split();
-            Assert.True(enumerator.MoveNext());
-            Assert.Equal(new Range(0, 0), enumerator.Current);
-            Assert.False(enumerator.MoveNext());
-
-            buffer = " ";
-            enumerator = buffer.Split();
-            Assert.True(enumerator.MoveNext());
-            Assert.Equal(new Range(0, 0), enumerator.Current);
-            Assert.True(enumerator.MoveNext());
-            Assert.Equal(new Range(1, 1), enumerator.Current);
-            Assert.False(enumerator.MoveNext());
-        }
-
-        [Fact]
-        public static void ValidateArguments_OverloadWithROSSeparator()
-        {
-            // Default buffer
-            ReadOnlySpan<char> buffer = default;
-
-            SpanSplitEnumerator<char>  enumerator = buffer.Split(default(char));
-            Assert.True(enumerator.MoveNext());
-            Assert.Equal(enumerator.Current, new Range(0, 0));
-            Assert.False(enumerator.MoveNext());
-
-            enumerator = buffer.Split(' ');
-            Assert.True(enumerator.MoveNext());
-            Assert.Equal(enumerator.Current, new Range(0, 0));
-            Assert.False(enumerator.MoveNext());
-
-            // Empty buffer
-            buffer = "";
-
-            enumerator = buffer.Split(default(char));
-            Assert.True(enumerator.MoveNext());
-            Assert.Equal(enumerator.Current, new Range(0, 0));
-            Assert.False(enumerator.MoveNext());
-
-            enumerator = buffer.Split(' ');
-            Assert.True(enumerator.MoveNext());
-            Assert.Equal(enumerator.Current, new Range(0, 0));
-            Assert.False(enumerator.MoveNext());
-
-            // Single whitespace buffer
-            buffer = " ";
-
-            enumerator = buffer.Split(default(char));
-            Assert.True(enumerator.MoveNext());
-            Assert.False(enumerator.MoveNext());
-
-            enumerator = buffer.Split(' ');
-            Assert.Equal(new Range(0, 0), enumerator.Current);
-            Assert.True(enumerator.MoveNext());
-            Assert.Equal(new Range(0, 0), enumerator.Current);
-            Assert.True(enumerator.MoveNext());
-            Assert.Equal(new Range(1, 1), enumerator.Current);
-            Assert.False(enumerator.MoveNext());
-        }
-
-        [Fact]
-        public static void ValidateArguments_OverloadWithStringSeparator()
-        {
-            // Default buffer
-            ReadOnlySpan<char> buffer = default;
-
-            SpanSplitEnumerator<char> enumerator = buffer.Split(null); // null is treated as empty string
-            Assert.True(enumerator.MoveNext());
-            Assert.Equal(enumerator.Current, new Range(0, 0));
-            Assert.False(enumerator.MoveNext());
-
-            enumerator = buffer.Split("");
-            Assert.True(enumerator.MoveNext());
-            Assert.Equal(enumerator.Current, new Range(0, 0));
-            Assert.False(enumerator.MoveNext());
-
-            enumerator = buffer.Split(" ");
-            Assert.True(enumerator.MoveNext());
-            Assert.Equal(enumerator.Current, new Range(0, 0));
-            Assert.False(enumerator.MoveNext());
-
-            // Empty buffer
-            buffer = "";
-
-            enumerator = buffer.Split(null);
-            Assert.True(enumerator.MoveNext());
-            Assert.Equal(enumerator.Current, new Range(0, 0));
-            Assert.False(enumerator.MoveNext());
-
-            enumerator = buffer.Split("");
-            Assert.True(enumerator.MoveNext());
-            Assert.Equal(enumerator.Current, new Range(0, 0));
-            Assert.False(enumerator.MoveNext());
-
-            enumerator = buffer.Split(" ");
-            Assert.True(enumerator.MoveNext());
-            Assert.Equal(enumerator.Current, new Range(0, 0));
-            Assert.False(enumerator.MoveNext());
-
-            // Single whitespace buffer
-            buffer = " ";
-
-            enumerator = buffer.Split(null); // null is treated as empty string
-            Assert.True(enumerator.MoveNext());
-            Assert.Equal(enumerator.Current, new Range(0, 0));
-            Assert.True(enumerator.MoveNext());
-            Assert.Equal(enumerator.Current, new Range(1, 1));
-            Assert.False(enumerator.MoveNext());
-
-            enumerator = buffer.Split("");
-            Assert.True(enumerator.MoveNext());
-            Assert.Equal(enumerator.Current, new Range(0, 0));
-            Assert.True(enumerator.MoveNext());
-            Assert.Equal(enumerator.Current, new Range(1, 1));
-            Assert.False(enumerator.MoveNext());
-
-            enumerator = buffer.Split(" ");
-            Assert.Equal(enumerator.Current, new Range(0, 0));
-            Assert.True(enumerator.MoveNext());
-            Assert.Equal(enumerator.Current, new Range(0, 0));
-            Assert.True(enumerator.MoveNext());
-            Assert.Equal(enumerator.Current, new Range(1, 1));
-            Assert.False(enumerator.MoveNext());
-        }
-
-        [Theory]
-        [InlineData("", ',', new[] { "" })]
-        [InlineData(" ", ' ', new[] { "", "" })]
-        [InlineData(",", ',', new[] { "", "" })]
-        [InlineData("     ", ' ', new[] { "", "", "", "", "", "" })]
-        [InlineData(",,", ',', new[] { "", "", "" })]
-        [InlineData("ab", ',', new[] { "ab" })]
-        [InlineData("a,b", ',', new[] { "a", "b" })]
-        [InlineData("a,", ',', new[] { "a", "" })]
-        [InlineData(",b", ',', new[] { "", "b" })]
-        [InlineData(",a,b", ',', new[] { "", "a", "b" })]
-        [InlineData("a,b,", ',', new[] { "a", "b", "" })]
-        [InlineData("a,b,c", ',', new[] { "a", "b", "c" })]
-        [InlineData("a,,c", ',', new[] { "a", "", "c" })]
-        [InlineData(",a,b,c", ',', new[] { "", "a", "b", "c" })]
-        [InlineData("a,b,c,", ',', new[] { "a", "b", "c", "" })]
-        [InlineData(",a,b,c,", ',', new[] { "", "a", "b", "c", "" })]
-        [InlineData("first,second", ',', new[] { "first", "second" })]
-        [InlineData("first,", ',', new[] { "first", "" })]
-        [InlineData(",second", ',', new[] { "", "second" })]
-        [InlineData(",first,second", ',', new[] { "", "first", "second" })]
-        [InlineData("first,second,", ',', new[] { "first", "second", "" })]
-        [InlineData("first,second,third", ',', new[] { "first", "second", "third" })]
-        [InlineData("first,,third", ',', new[] { "first", "", "third" })]
-        [InlineData(",first,second,third", ',', new[] { "", "first", "second", "third" })]
-        [InlineData("first,second,third,", ',', new[] { "first", "second", "third", "" })]
-        [InlineData(",first,second,third,", ',', new[] { "", "first", "second", "third", "" })]
-        [InlineData("Foo Bar Baz", ' ', new[] { "Foo", "Bar", "Baz" })]
-        [InlineData("Foo Bar Baz ", ' ', new[] { "Foo", "Bar", "Baz", "" })]
-        [InlineData(" Foo Bar Baz ", ' ', new[] { "", "Foo", "Bar", "Baz", "" })]
-        [InlineData(" Foo  Bar Baz ", ' ', new[] { "", "Foo", "", "Bar", "Baz", "" })]
-        [InlineData("Foo Baz Bar", default(char), new[] { "Foo Baz Bar" })]
-        [InlineData("Foo Baz \x0000 Bar", default(char), new[] { "Foo Baz ", " Bar" })]
-        [InlineData("Foo Baz \x0000 Bar\x0000", default(char), new[] { "Foo Baz ", " Bar", "" })]
-        public static void SpanSplitCharSeparator(string valueParam, char separator, string[] expectedParam)
-        {
-            char[][] expected = expectedParam.Select(x => x.ToCharArray()).ToArray();
-            AssertEqual(expected, valueParam, valueParam.AsSpan().Split(separator));
-        }
-
-        [Theory]
-        [InlineData("", new[] { "" })]
-        [InlineData(" ", new[] { "", "" })]
-        [InlineData("     ", new[] { "", "", "", "", "", "" })]
-        [InlineData("  ", new[] { "", "", "" })]
-        [InlineData("ab", new[] { "ab" })]
-        [InlineData("a b", new[] { "a", "b" })]
-        [InlineData("a ", new[] { "a", "" })]
-        [InlineData(" b", new[] { "", "b" })]
-        [InlineData("Foo Bar Baz", new[] { "Foo", "Bar", "Baz" })]
-        [InlineData("Foo Bar Baz ", new[] { "Foo", "Bar", "Baz", "" })]
-        [InlineData(" Foo Bar Baz ", new[] { "", "Foo", "Bar", "Baz", "" })]
-        [InlineData(" Foo  Bar Baz ", new[] { "", "Foo", "", "Bar", "Baz", "" })]
-        public static void SpanSplitDefaultCharSeparator(string valueParam, string[] expectedParam)
-        {
-            char[][] expected = expectedParam.Select(x => x.ToCharArray()).ToArray();
-            AssertEqual(expected, valueParam, valueParam.AsSpan().Split());
-        }
-
-        [Theory]
-        [InlineData(" Foo Bar Baz,", ", ", new[] { " Foo Bar Baz," })]
-        [InlineData(" Foo Bar Baz, ", ", ", new[] { " Foo Bar Baz", "" })]
-        [InlineData(", Foo Bar Baz, ", ", ", new[] { "", "Foo Bar Baz", "" })]
-        [InlineData(", Foo, Bar, Baz, ", ", ", new[] { "", "Foo", "Bar", "Baz", "" })]
-        [InlineData(", , Foo Bar, Baz", ", ", new[] { "", "", "Foo Bar", "Baz" })]
-        [InlineData(", , Foo Bar, Baz, , ", ", ", new[] { "", "", "Foo Bar", "Baz", "", "" })]
-        [InlineData(", , , , , ", ", ", new[] { "", "", "", "", "", "" })]
-        [InlineData("     ", " ", new[] { "", "", "", "", "", "" })]
-        [InlineData("  Foo, Bar  Baz  ", "  ", new[] { "", "Foo, Bar", "Baz", "" })]
-        public static void SpanSplitStringSeparator(string valueParam, string separator, string[] expectedParam)
-        {
-            char[][] expected = expectedParam.Select(x => x.ToCharArray()).ToArray();
-            AssertEqual(expected, valueParam, valueParam.AsSpan().Split(separator));
-        }
-
-        private static void AssertEqual<T>(T[][] items, ReadOnlySpan<T> orig, SpanSplitEnumerator<T> source) where T : IEquatable<T>
-        {
-            foreach (var item in items)
-            {
-                Assert.True(source.MoveNext());
-                var slice = orig[source.Current];
-                Assert.Equal(item, slice.ToArray());
-            }
-            Assert.False(source.MoveNext());
-        }
-    }
-}
diff --git a/src/libraries/System.Memory/tests/System.Memory.Tests.csproj b/src/libraries/System.Memory/tests/System.Memory.Tests.csproj
index 952b6d8f9dff5..d9b36dc5649f8 100644
--- a/src/libraries/System.Memory/tests/System.Memory.Tests.csproj
+++ b/src/libraries/System.Memory/tests/System.Memory.Tests.csproj
@@ -165,7 +165,6 @@
     <Compile Include="ReadOnlySpan\SequenceEqual.long.cs" />
     <Compile Include="ReadOnlySpan\SequenceEqual.T.cs" />
     <Compile Include="ReadOnlySpan\Slice.cs" />
-    <Compile Include="ReadOnlySpan\Split.char.cs" />
     <Compile Include="ReadOnlySpan\StartsWith.byte.cs" />
     <Compile Include="ReadOnlySpan\StartsWith.long.cs" />
     <Compile Include="ReadOnlySpan\StartsWith.T.cs" />
diff --git a/src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems b/src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems
index cdb6bc08024d4..5d3e8a89d5f96 100644
--- a/src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems
+++ b/src/libraries/System.Private.CoreLib/src/System.Private.CoreLib.Shared.projitems
@@ -416,7 +416,6 @@
     <Compile Include="$(MSBuildThisFileDirectory)System\MemoryDebugView.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\MemoryExtensions.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\MemoryExtensions.Globalization.cs" />
-    <Compile Include="$(MSBuildThisFileDirectory)System\MemoryExtensions.Split.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\MemoryExtensions.Trim.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\MethodAccessException.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\MidpointRounding.cs" />
@@ -857,7 +856,6 @@
     <Compile Include="$(MSBuildThisFileDirectory)System\SpanHelpers.Char.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\SpanHelpers.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\SpanHelpers.T.cs" />
-    <Compile Include="$(MSBuildThisFileDirectory)System\SpanSplitEnumerator.T.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\SR.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\StackOverflowException.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System\String.Comparison.cs" />
diff --git a/src/libraries/System.Private.CoreLib/src/System/MemoryExtensions.Split.cs b/src/libraries/System.Private.CoreLib/src/System/MemoryExtensions.Split.cs
deleted file mode 100644
index 77426e5843e6c..0000000000000
--- a/src/libraries/System.Private.CoreLib/src/System/MemoryExtensions.Split.cs
+++ /dev/null
@@ -1,38 +0,0 @@
-// 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.
-
-namespace System
-{
-    public static partial class MemoryExtensions
-    {
-        /// <summary>
-        /// Returns a type that allows for enumeration of each element within a split span
-        /// using a single space as a separator character.
-        /// </summary>
-        /// <param name="span">The source span to be enumerated.</param>
-        /// <returns>Returns a <see cref="System.SpanSplitEnumerator{T}"/>.</returns>
-        public static SpanSplitEnumerator<char> Split(this ReadOnlySpan<char> span)
-            => new SpanSplitEnumerator<char>(span, ' ');
-
-        /// <summary>
-        /// Returns a type that allows for enumeration of each element within a split span
-        /// using the provided separator character.
-        /// </summary>
-        /// <param name="span">The source span to be enumerated.</param>
-        /// <param name="separator">The separator character to be used to split the provided span.</param>
-        /// <returns>Returns a <see cref="System.SpanSplitEnumerator{T}"/>.</returns>
-        public static SpanSplitEnumerator<char> Split(this ReadOnlySpan<char> span, char separator)
-            => new SpanSplitEnumerator<char>(span, separator);
-
-        /// <summary>
-        /// Returns a type that allows for enumeration of each element within a split span
-        /// using the provided separator string.
-        /// </summary>
-        /// <param name="span">The source span to be enumerated.</param>
-        /// <param name="separator">The separator string to be used to split the provided span.</param>
-        /// <returns>Returns a <see cref="System.SpanSplitEnumerator{T}"/>.</returns>
-        public static SpanSplitEnumerator<char> Split(this ReadOnlySpan<char> span, string separator)
-            => new SpanSplitEnumerator<char>(span, separator ?? string.Empty);
-    }
-}
diff --git a/src/libraries/System.Private.CoreLib/src/System/SpanSplitEnumerator.T.cs b/src/libraries/System.Private.CoreLib/src/System/SpanSplitEnumerator.T.cs
deleted file mode 100644
index 69382459b26e4..0000000000000
--- a/src/libraries/System.Private.CoreLib/src/System/SpanSplitEnumerator.T.cs
+++ /dev/null
@@ -1,87 +0,0 @@
-// 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.
-
-namespace System
-{
-    /// <summary>
-    /// <see cref="System.SpanSplitEnumerator{T}"/> allows for enumeration of each element within a <see cref="System.ReadOnlySpan{T}"/>
-    /// that has been split using a provided separator.
-    /// </summary>
-    public ref struct SpanSplitEnumerator<T> where T : IEquatable<T>
-    {
-        private readonly ReadOnlySpan<T> _buffer;
-
-        private readonly ReadOnlySpan<T> _separators;
-        private readonly T _separator;
-
-        private readonly int _separatorLength;
-        private readonly bool _splitOnSingleToken;
-
-        private readonly bool _isInitialized;
-
-        private int _startCurrent;
-        private int _endCurrent;
-        private int _startNext;
-
-        /// <summary>
-        /// Returns an enumerator that allows for iteration over the split span.
-        /// </summary>
-        /// <returns>Returns a <see cref="System.SpanSplitEnumerator{T}"/> that can be used to iterate over the split span.</returns>
-        public SpanSplitEnumerator<T> GetEnumerator() => this;
-
-        /// <summary>
-        /// Returns the current element of the enumeration.
-        /// </summary>
-        /// <returns>Returns a <see cref="System.Range"/> instance that indicates the bounds of the current element withing the source span.</returns>
-        public Range Current => new Range(_startCurrent, _endCurrent);
-
-        internal SpanSplitEnumerator(ReadOnlySpan<T> span, ReadOnlySpan<T> separators)
-        {
-            _isInitialized = true;
-            _buffer = span;
-            _separators = separators;
-            _separator = default!;
-            _splitOnSingleToken = false;
-            _separatorLength = _separators.Length != 0 ? _separators.Length : 1;
-            _startCurrent = 0;
-            _endCurrent = 0;
-            _startNext = 0;
-        }
-
-        internal SpanSplitEnumerator(ReadOnlySpan<T> span, T separator)
-        {
-            _isInitialized = true;
-            _buffer = span;
-            _separator = separator;
-            _separators = default;
-            _splitOnSingleToken = true;
-            _separatorLength = 1;
-            _startCurrent = 0;
-            _endCurrent = 0;
-            _startNext = 0;
-        }
-
-        /// <summary>
-        /// Advances the enumerator to the next element of the enumeration.
-        /// </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 enumeration.</returns>
-        public bool MoveNext()
-        {
-            if (!_isInitialized || _startNext > _buffer.Length)
-            {
-                return false;
-            }
-
-            ReadOnlySpan<T> slice = _buffer.Slice(_startNext);
-            _startCurrent = _startNext;
-
-            int separatorIndex = _splitOnSingleToken ? slice.IndexOf(_separator) : slice.IndexOf(_separators);
-            int elementLength = (separatorIndex != -1 ? separatorIndex : slice.Length);
-
-            _endCurrent = _startCurrent + elementLength;
-            _startNext = _endCurrent + _separatorLength;
-            return true;
-        }
-    }
-}