C# Code Snippets

Slicer

public static T[] GetSlices<T>(this IEnumerable<KeyValuePair<T, int>> sliceCounters)
{
    var sliceArray = sliceCounters.ToArray();
    int total = sliceArray.Sum(slice => slice.Value);
    var slices = new KeyValuePair<T, double>[total];
    int j = 0;
    foreach (var slice in sliceArray)
    {
        double interval = (double)total / slice.Value;
        double sortWeight = 0.0;
        for (int i = 0; i < slice.Value; i++)
        {
            slices[j++] = new KeyValuePair<T, double>(slice.Key, sortWeight);
            sortWeight += interval;
        }
    }
    return slices.OrderBy(p => p.Value).Select(p => p.Key).ToArray();
}

Example

var sliceCounters = new Dictionary<string, int> {{"A", 3}, {"B", 5}, {"C", 7}};
var slices = sliceCounters.GetSlices();
Console.WriteLine(string.Join(" ", slices));

Result:

A B C C B C A B C C B A C B C

Partitions

public static IEnumerable<IEnumerable<T>> CreatePartitions<T>(this IEnumerable<T> entries, int partitionSize)
{
    return entries
        .Select((entry, index) => new { entry, index })
        .GroupBy(g => g.index / partitionSize, i => i.entry);
}

Example

// Create random test data set
var random = new Random();
var entries = new byte[random.Next(1000) + 100];
random.NextBytes(entries);

foreach (var partition in entries.CreatePartitions(10))
{
    Console.WriteLine();
    foreach (var entry in partition)
    {
        Console.WriteLine("      " + entry);
    }
}

Power of two

public static bool IsPowerOfTwo(int x)
{
    return ((x & (x - 1)) == 0);
}

Example

var result = Enumerable.Range(0, 100).Where(IsPowerOfTwo).Select(i => i.ToString());
Console.WriteLine(string.Join(" ", result));

Result:

0 1 2 4 8 16 32 64

Size of a struct

public static int SizeOf<T>() where T : struct
{
    return System.Runtime.InteropServices.Marshal.SizeOf(typeof(T));
}

Example

var size = SizeOf<System.Drawing.Size>();
Console.WriteLine(size);

Result:

8

Binary string

public static string ToBinaryString(uint value, int width = 0)
{
    const int char0 = '0';
    var ch = new char[32];
    var w = ch.Length - width;
    if (w >= ch.Length) w = ch.Length - 1;
    else if (w < 0) w = 0;
    int i = ch.Length;
    while (value > 0)
    {
        i--;
        ch[i] = (char) (char0 + (value & 1));
        value >>= 1;
    }
    while (i > w)
    {
        i--;
        ch[i] = (char) char0;
    }
    return new string(ch, i, ch.Length - i);
}

Hex string

public static string ToHexString(uint value, int width = 0, bool lower = false)
{
    const int char0 = '0';
    const int charA = 'A' - 10;
    var cc = lower ? 32 : 0;
    var ch = new char[8];
    var w = ch.Length - width;
    if (w >= ch.Length) w = ch.Length - 1;
    else if (w < 0) w = 0;
    int i = ch.Length;
    while (value > 0)
    {
        i--;
        var ci = value & 15;
        ch[i] = (char) (ci < 10 ? char0 + ci : (charA + ci) ^ cc);
        value >>= 4;
    }
    while (i > w)
    {
        i--;
        ch[i] = (char) char0;
    }
    return new string(ch, i, ch.Length - i);
}