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Added GitBits and SetBits methods

pull/10/head
David Hall 2018-08-07 17:21:43 -06:00
parent 4ff39de15f
commit acb6097003
1 changed files with 33 additions and 2 deletions
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35
Core/Extensions/BitHelper.cs
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@ -1,4 +1,5 @@
using System;
using System.Runtime.InteropServices;
namespace Vanara.Extensions
{
@ -8,9 +9,22 @@ namespace Vanara.Extensions
/// <summary>Gets the bit value at the specified index in a bit vector.</summary>
/// <typeparam name="T">The type of the bit vector. Must be of type <see cref="IConvertible"/>.</typeparam>
/// <param name="bits">The bit vector.</param>
/// <param name="idx">The index of the bit to get.</param>
/// <param name="idx">The zero-based index of the bit to get.</param>
/// <returns><see langword="true"/> if the bit is set (1); <see langword="false"/> otherwise.</returns>
public static bool GetBit<T>(ref T bits, byte idx) where T : IConvertible => (bits.ToInt64(null) & 1 << idx) != 0;
public static bool GetBit<T>(T bits, byte idx) where T : IConvertible => (idx < (Marshal.SizeOf(typeof(T)) * 8)) ? (bits.ToInt64(null) & 1 << idx) != 0 : throw new ArgumentOutOfRangeException(nameof(idx));
/// <summary>Gets the bit array value from the specified range in a bit vector.</summary>
/// <typeparam name="T">The type of the bit vector. Must be of type <see cref="IConvertible"/>.</typeparam>
/// <param name="bits">The bit vector.</param>
/// <param name="startIdx">The zero-based start index of the bit range to get.</param>
/// <param name="count">The number of sequential bits to fetch starting at <paramref name="startIdx"/>.</param>
/// <returns>The value of the requested bit range.</returns>
public static T GetBits<T>(T bits, byte startIdx, byte count) where T : IConvertible
{
if (startIdx >= (Marshal.SizeOf(typeof(T)) * 8)) throw new ArgumentOutOfRangeException(nameof(startIdx));
if (count + startIdx > (Marshal.SizeOf(typeof(T)) * 8)) throw new ArgumentOutOfRangeException(nameof(count));
return (T)Convert.ChangeType((bits.ToInt64(null) >> startIdx) & ((1 << count) - 1), typeof(T));
}
/// <summary>Sets the bit value at the specified index in a bit vector.</summary>
/// <typeparam name="T">The type of the bit vector. Must be of type <see cref="IConvertible"/>.</typeparam>
@ -19,9 +33,26 @@ namespace Vanara.Extensions
/// <param name="value">If set to <see langword="true"/>, set the bit (= 1); otherwise, clear the bit (= 0).</param>
public static void SetBit<T>(ref T bits, byte idx, bool value) where T : IConvertible
{
if (idx >= (Marshal.SizeOf(typeof(T)) * 8)) throw new ArgumentOutOfRangeException(nameof(idx));
long bit = 1 << idx;
var l = bits.ToInt64(null);
bits = (T)Convert.ChangeType(value ? l | bit : l & ~bit, typeof(T));
}
/// <summary>Sets the bit values at the specified range in a bit vector.</summary>
/// <typeparam name="T">The type of the bit vector. Must be of type <see cref="IConvertible"/>.</typeparam>
/// <typeparam name="TValue">The type of the value. Must be of type <see cref="IConvertible"/>.</typeparam>
/// <param name="bits">The bit vector.</param>
/// <param name="startIdx">The zero-based start index of the bit range to set.</param>
/// <param name="count">The number of sequential bits to set starting at <paramref name="startIdx"/>.</param>
/// <param name="value">The value to set within the specified range of <paramref name="bits"/>.</param>
public static void SetBits<T, TValue>(ref T bits, byte startIdx, byte count, TValue value) where T : IConvertible where TValue : IConvertible
{
if (startIdx >= (Marshal.SizeOf(typeof(T)) * 8)) throw new ArgumentOutOfRangeException(nameof(startIdx));
if (count + startIdx > (Marshal.SizeOf(typeof(T)) * 8)) throw new ArgumentOutOfRangeException(nameof(count));
var val = value.ToInt64(null);
if (val >= (1 << count)) throw new ArgumentOutOfRangeException(nameof(value));
bits = (T)Convert.ChangeType(bits.ToInt64(null) & ~(((1 << count) - 1) << startIdx) | (val << startIdx), typeof(T));
}
}
}