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CrowdControl/Assets/Plugins/UniTask/Runtime/Internal/ArrayUtil.cs

74 lines
2.1 KiB
C#

#pragma warning disable CS1591 // Missing XML comment for publicly visible type or member
using System;
using System.Collections.Generic;
using System.Runtime.CompilerServices;
namespace Cysharp.Threading.Tasks.Internal
{
internal static class ArrayUtil
{
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static void EnsureCapacity<T>(ref T[] array, int index)
{
if (array.Length <= index)
{
EnsureCore(ref array, index);
}
}
// rare case, no inlining.
[MethodImpl(MethodImplOptions.NoInlining)]
static void EnsureCore<T>(ref T[] array, int index)
{
var newSize = array.Length * 2;
var newArray = new T[(index < newSize) ? newSize : (index * 2)];
Array.Copy(array, 0, newArray, 0, array.Length);
array = newArray;
}
/// <summary>
/// Optimizing utility to avoid .ToArray() that creates buffer copy(cut to just size).
/// </summary>
public static (T[] array, int length) Materialize<T>(IEnumerable<T> source)
{
if (source is T[] array)
{
return (array, array.Length);
}
var defaultCount = 4;
if (source is ICollection<T> coll)
{
defaultCount = coll.Count;
var buffer = new T[defaultCount];
coll.CopyTo(buffer, 0);
return (buffer, defaultCount);
}
else if (source is IReadOnlyCollection<T> rcoll)
{
defaultCount = rcoll.Count;
}
if (defaultCount == 0)
{
return (Array.Empty<T>(), 0);
}
{
var index = 0;
var buffer = new T[defaultCount];
foreach (var item in source)
{
EnsureCapacity(ref buffer, index);
buffer[index++] = item;
}
return (buffer, index);
}
}
}
}