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Diffstat (limited to 'netcore/System.Private.CoreLib/shared/System/Index.cs')
| -rw-r--r-- | netcore/System.Private.CoreLib/shared/System/Index.cs | 150 |
1 files changed, 0 insertions, 150 deletions
diff --git a/netcore/System.Private.CoreLib/shared/System/Index.cs b/netcore/System.Private.CoreLib/shared/System/Index.cs deleted file mode 100644 index 8f7c12eaac7..00000000000 --- a/netcore/System.Private.CoreLib/shared/System/Index.cs +++ /dev/null @@ -1,150 +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.Diagnostics; -using System.Runtime.CompilerServices; - -namespace System -{ - /// <summary>Represent a type can be used to index a collection either from the start or the end.</summary> - /// <remarks> - /// Index is used by the C# compiler to support the new index syntax - /// <code> - /// int[] someArray = new int[5] { 1, 2, 3, 4, 5 } ; - /// int lastElement = someArray[^1]; // lastElement = 5 - /// </code> - /// </remarks> - public readonly struct Index : IEquatable<Index> - { - private readonly int _value; - - /// <summary>Construct an Index using a value and indicating if the index is from the start or from the end.</summary> - /// <param name="value">The index value. it has to be zero or positive number.</param> - /// <param name="fromEnd">Indicating if the index is from the start or from the end.</param> - /// <remarks> - /// If the Index constructed from the end, index value 1 means pointing at the last element and index value 0 means pointing at beyond last element. - /// </remarks> - [MethodImpl(MethodImplOptions.AggressiveInlining)] - public Index(int value, bool fromEnd = false) - { - if (value < 0) - { - ThrowHelper.ThrowValueArgumentOutOfRange_NeedNonNegNumException(); - } - - if (fromEnd) - _value = ~value; - else - _value = value; - } - - // The following private constructors mainly created for perf reason to avoid the checks - private Index(int value) - { - _value = value; - } - - /// <summary>Create an Index pointing at first element.</summary> - public static Index Start => new Index(0); - - /// <summary>Create an Index pointing at beyond last element.</summary> - public static Index End => new Index(~0); - - /// <summary>Create an Index from the start at the position indicated by the value.</summary> - /// <param name="value">The index value from the start.</param> - [MethodImpl(MethodImplOptions.AggressiveInlining)] - public static Index FromStart(int value) - { - if (value < 0) - { - ThrowHelper.ThrowValueArgumentOutOfRange_NeedNonNegNumException(); - } - - return new Index(value); - } - - /// <summary>Create an Index from the end at the position indicated by the value.</summary> - /// <param name="value">The index value from the end.</param> - [MethodImpl(MethodImplOptions.AggressiveInlining)] - public static Index FromEnd(int value) - { - if (value < 0) - { - ThrowHelper.ThrowValueArgumentOutOfRange_NeedNonNegNumException(); - } - - return new Index(~value); - } - - /// <summary>Returns the index value.</summary> - public int Value - { - get - { - if (_value < 0) - return ~_value; - else - return _value; - } - } - - /// <summary>Indicates whether the index is from the start or the end.</summary> - public bool IsFromEnd => _value < 0; - - /// <summary>Calculate the offset from the start using the giving collection length.</summary> - /// <param name="length">The length of the collection that the Index will be used with. length has to be a positive value</param> - /// <remarks> - /// For performance reason, we don't validate the input length parameter and the returned offset value against negative values. - /// we don't validate either the returned offset is greater than the input length. - /// It is expected Index will be used with collections which always have non negative length/count. If the returned offset is negative and - /// then used to index a collection will get out of range exception which will be same affect as the validation. - /// </remarks> - [MethodImpl(MethodImplOptions.AggressiveInlining)] - public int GetOffset(int length) - { - int offset = _value; - if (IsFromEnd) - { - // offset = length - (~value) - // offset = length + (~(~value) + 1) - // offset = length + value + 1 - - offset += length + 1; - } - return offset; - } - - /// <summary>Indicates whether the current Index object is equal to another object of the same type.</summary> - /// <param name="value">An object to compare with this object</param> - public override bool Equals(object? value) => value is Index && _value == ((Index)value)._value; - - /// <summary>Indicates whether the current Index object is equal to another Index object.</summary> - /// <param name="other">An object to compare with this object</param> - public bool Equals(Index other) => _value == other._value; - - /// <summary>Returns the hash code for this instance.</summary> - public override int GetHashCode() => _value; - - /// <summary>Converts integer number to an Index.</summary> - public static implicit operator Index(int value) => FromStart(value); - - /// <summary>Converts the value of the current Index object to its equivalent string representation.</summary> - public override string ToString() - { - if (IsFromEnd) - return ToStringFromEnd(); - - return ((uint)Value).ToString(); - } - - private string ToStringFromEnd() - { - Span<char> span = stackalloc char[11]; // 1 for ^ and 10 for longest possible uint value - bool formatted = ((uint)Value).TryFormat(span.Slice(1), out int charsWritten); - Debug.Assert(formatted); - span[0] = '^'; - return new string(span.Slice(0, charsWritten + 1)); - } - } -} |