1 // Licensed to the .NET Foundation under one or more agreements.
2 // The .NET Foundation licenses this file to you under the MIT license.
3 // See the LICENSE file in the project root for more information.
5 using System.ComponentModel;
6 using System.Diagnostics;
7 using System.Runtime.CompilerServices;
9 using System.Runtime.Versioning;
11 #pragma warning disable 0809 //warning CS0809: Obsolete member 'Span<T>.Equals(object)' overrides non-obsolete member 'object.Equals(object)'
16 /// Span represents a contiguous region of arbitrary memory. Unlike arrays, it can point to either managed
17 /// or native memory, or to memory allocated on the stack. It is type- and memory-safe.
19 [DebuggerTypeProxy(typeof(SpanDebugView<>))]
20 [DebuggerDisplay("{ToString(),raw}")]
21 public readonly ref partial struct Span<T>
24 /// The number of items in the span.
36 /// Returns true if Length is 0.
43 // Workaround for https://github.com/dotnet/coreclr/issues/19620
44 return 0 >= (uint)_length;
49 /// Returns false if left and right point at the same memory and have the same length. Note that
50 /// this does *not* check to see if the *contents* are equal.
52 public static bool operator !=(Span<T> left, Span<T> right) => !(left == right);
55 /// This method is not supported as spans cannot be boxed. To compare two spans, use operator==.
56 /// <exception cref="System.NotSupportedException">
57 /// Always thrown by this method.
60 [Obsolete("Equals() on Span will always throw an exception. Use == instead.")]
61 [EditorBrowsable(EditorBrowsableState.Never)]
62 public override bool Equals(object obj)
64 throw new NotSupportedException(SR.NotSupported_CannotCallEqualsOnSpan);
68 /// This method is not supported as spans cannot be boxed.
69 /// <exception cref="System.NotSupportedException">
70 /// Always thrown by this method.
73 [Obsolete("GetHashCode() on Span will always throw an exception.")]
74 [EditorBrowsable(EditorBrowsableState.Never)]
75 public override int GetHashCode()
77 throw new NotSupportedException(SR.NotSupported_CannotCallGetHashCodeOnSpan);
81 /// Defines an implicit conversion of an array to a <see cref="Span{T}"/>
83 public static implicit operator Span<T>(T[] array) => new Span<T>(array);
86 /// Defines an implicit conversion of a <see cref="ArraySegment{T}"/> to a <see cref="Span{T}"/>
88 public static implicit operator Span<T>(ArraySegment<T> segment)
89 => new Span<T>(segment.Array, segment.Offset, segment.Count);
92 /// Returns an empty <see cref="Span{T}"/>
94 public static Span<T> Empty => default;
96 /// <summary>Gets an enumerator for this span.</summary>
97 public Enumerator GetEnumerator() => new Enumerator(this);
99 /// <summary>Enumerates the elements of a <see cref="Span{T}"/>.</summary>
100 public ref struct Enumerator
102 /// <summary>The span being enumerated.</summary>
103 private readonly Span<T> _span;
104 /// <summary>The next index to yield.</summary>
107 /// <summary>Initialize the enumerator.</summary>
108 /// <param name="span">The span to enumerate.</param>
109 [MethodImpl(MethodImplOptions.AggressiveInlining)]
110 internal Enumerator(Span<T> span)
116 /// <summary>Advances the enumerator to the next element of the span.</summary>
117 [MethodImpl(MethodImplOptions.AggressiveInlining)]
118 public bool MoveNext()
120 int index = _index + 1;
121 if (index < _span.Length)
130 /// <summary>Gets the element at the current position of the enumerator.</summary>
133 [MethodImpl(MethodImplOptions.AggressiveInlining)]
134 get => ref _span[_index];