IntXLib/IntXLib/Bits.cs at master · devoyster/IntXLib · GitHub

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using System;

namespace IntXLib

{

/// <summary>

/// Contains helping methods to with with bits in dword (<see cref="UInt32" />).

/// </summary>

[CLSCompliant(false)]

static public class Bits

{

/// <summary>

/// Returns number of leading zero bits in int.

/// </summary>

/// <param name="x">Int value.</param>

/// <returns>Number of leading zero bits.</returns>

static public int Nlz(uint x)

{

if (x == 0) return 32;

int n = 1;

if ((x >> 16) == 0) { n += 16; x <<= 16; }

if ((x >> 24) == 0) { n += 8; x <<= 8; }

if ((x >> 28) == 0) { n += 4; x <<= 4; }

if ((x >> 30) == 0) { n += 2; x <<= 2; }

return n - (int)(x >> 31);

}

/// <summary>

/// Counts position of the most significant bit in int.

/// Can also be used as Floor(Log2(<paramref name="x" />)).

/// </summary>

/// <param name="x">Int value.</param>

/// <returns>Position of the most significant one bit (-1 if all zeroes).</returns>

static public int Msb(uint x)

{

return 31 - Nlz(x);

}

/// <summary>

/// Ceil(Log2(<paramref name="x" />)).

/// </summary>

/// <param name="x">Int value.</param>

/// <returns>Ceil of the Log2.</returns>

static public int CeilLog2(uint x)

{

int msb = Msb(x);

if (x != 1U << msb)

{

++msb;

}

return msb;

}

IntXLib/IntXLib/Bits.cs at master · devoyster/IntXLib · GitHub

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