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.
48 /// Returns false if left and right point at the same memory and have the same length. Note that
49 /// this does *not* check to see if the *contents* are equal.
51 public static bool operator !=(Span<T> left, Span<T> right) => !(left == right);
54 /// This method is not supported as spans cannot be boxed. To compare two spans, use operator==.
55 /// <exception cref="System.NotSupportedException">
56 /// Always thrown by this method.
59 [Obsolete("Equals() on Span will always throw an exception. Use == instead.")]
60 [EditorBrowsable(EditorBrowsableState.Never)]
61 public override bool Equals(object obj)
63 throw new NotSupportedException(SR.NotSupported_CannotCallEqualsOnSpan);
67 /// This method is not supported as spans cannot be boxed.
68 /// <exception cref="System.NotSupportedException">
69 /// Always thrown by this method.
72 [Obsolete("GetHashCode() on Span will always throw an exception.")]
73 [EditorBrowsable(EditorBrowsableState.Never)]
74 public override int GetHashCode()
76 throw new NotSupportedException(SR.NotSupported_CannotCallGetHashCodeOnSpan);
80 /// Defines an implicit conversion of an array to a <see cref="Span{T}"/>
82 public static implicit operator Span<T>(T[] array) => new Span<T>(array);
85 /// Defines an implicit conversion of a <see cref="ArraySegment{T}"/> to a <see cref="Span{T}"/>
87 public static implicit operator Span<T>(ArraySegment<T> segment)
88 => new Span<T>(segment.Array, segment.Offset, segment.Count);
91 /// Returns an empty <see cref="Span{T}"/>
93 public static Span<T> Empty => default;
95 /// <summary>Gets an enumerator for this span.</summary>
96 public Enumerator GetEnumerator() => new Enumerator(this);
98 /// <summary>Enumerates the elements of a <see cref="Span{T}"/>.</summary>
99 public ref struct Enumerator
101 /// <summary>The span being enumerated.</summary>
102 private readonly Span<T> _span;
103 /// <summary>The next index to yield.</summary>
106 /// <summary>Initialize the enumerator.</summary>
107 /// <param name="span">The span to enumerate.</param>
108 [MethodImpl(MethodImplOptions.AggressiveInlining)]
109 internal Enumerator(Span<T> span)
115 /// <summary>Advances the enumerator to the next element of the span.</summary>
116 [MethodImpl(MethodImplOptions.AggressiveInlining)]
117 public bool MoveNext()
119 int index = _index + 1;
120 if (index < _span.Length)
129 /// <summary>Gets the element at the current position of the enumerator.</summary>
132 [MethodImpl(MethodImplOptions.AggressiveInlining)]
133 get => ref _span[_index];