RoyalLibrary/src/RoyalLibrary/SortingExtensions.cs at master · ByteDecoder/RoyalLibrary · GitHub

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using System;

using System.Collections.Generic;

using System.Linq;

using System.Threading.Tasks;

using ByteDecoder.Common.GuardClauses;

namespace ByteDecoder.RoyalLibrary

{

/// <summary>

/// Advanced sorting for collections

/// </summary>

public static class SortingExtensions

{

/// <summary>

/// returns a new sorted ICollection

/// </summary>

/// <param name="source"></param>

/// <returns>An Enumerable sorted collection by LastName</returns>

public static async Task<ICollection<string>> SortByLastNameAsync(this IEnumerable<string> source)

{

Guard.Break.IfArgumentIsNull(source, nameof(source));

var enumerable = source as string[] ?? source.ToArray();

var rowsCount = enumerable.Count();

if (rowsCount == 0) return (ICollection<string>)source;

byte lastSpaceIndex;

string firstName, lastName;

var orderedList = new SortedList<string, string>() { Capacity = rowsCount };

await Task.Run(() =>

{

foreach (var item in enumerable)

{

var spaces = item.Count(char.IsWhiteSpace);

lastSpaceIndex = (byte)item.IndexOfNth(' ', spaces - 1);

firstName = item.Substring(0, lastSpaceIndex);

var lastNameLength = item.Length - firstName.Length;

lastName = item.Substring(lastSpaceIndex, lastNameLength);

orderedList.Add(lastName, firstName);

}

});

return orderedList.AsParallel().AsOrdered()

.Select((fullName) => fullName.Value + fullName.Key).ToList();

}

/// <summary>

/// returns a new sorted ICollection

/// </summary>

/// <param name="source"></param>

/// <param name="action"></param>

/// <returns>An Enumerable sorted collection by LastName</returns>

public static async Task<ICollection<string>> SortByLastNameAsync(this IEnumerable<string> source, Action<string> action)

{

var sortedList = await source.SortByLastNameAsync();

sortedList.AsParallel()

.AsOrdered()

.ForEach(action);

return sortedList;

}

/// <summary>

///

/// </summary>

/// <param name="str"></param>

/// <param name="value"></param>

/// <param name="nth"></param>

/// <returns></returns>

private static int IndexOfNth(this string str, char value, int nth)

{

if (nth < 0)

throw new ArgumentException($"Negative index found {nameof(nth)} has negative value, it must start at 0");

var offset = str.IndexOf(value);

for (var i = 0; i < nth; i++)

{

if (offset == -1) return -1;

offset = str.IndexOf(value, offset + 1);

}

return offset;

}

RoyalLibrary/src/RoyalLibrary/SortingExtensions.cs at master · ByteDecoder/RoyalLibrary · GitHub

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