mirror of https://github.com/dahall/Vanara.git
247 lines
12 KiB
C#
247 lines
12 KiB
C#
using System;
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using System.Collections.Generic;
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using System.ComponentModel;
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using System.Linq;
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namespace Vanara.Extensions
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{
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/// <summary>Extensions for enumerated types.</summary>
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public static class EnumExtensions
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{
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/// <summary>Gets the bit position of a flag that has a single bit, starting at 0.</summary>
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/// <typeparam name="T">The enumerated type.</typeparam>
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/// <param name="flags">The enumerated value.</param>
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/// <returns>The bit position, starting at 0, of the single bit flag specified in <paramref name="flags"/>.</returns>
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/// <exception cref="ArgumentException">The flag value is zero and has no bit position.</exception>
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/// <exception cref="ArithmeticException">The flag value has more than a single bit set.</exception>
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public static byte BitPosition<T>(this T flags) where T : struct, System.Enum
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{
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CheckHasFlags<T>();
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var flagValue = Convert.ToInt64(flags);
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if (flagValue == 0) throw new ArgumentException("The flag value is zero and has no bit position.");
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var r = Math.Log(flagValue, 2);
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if (r % 1 > 0) throw new ArithmeticException("The flag value has more than a single bit set.");
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return Convert.ToByte(r);
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}
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/// <summary>Throws an exception if a flag value does not exist in a specified enumeration.</summary>
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/// <typeparam name="T">The enumerated type.</typeparam>
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/// <param name="value">The value to check.</param>
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/// <param name="argName">Name of the argument to display in the exception. "value" is used if no value or <c>null</c> is supplied.</param>
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/// <exception cref="InvalidEnumArgumentException"></exception>
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public static void CheckHasValue<T>(T value, string argName = null) where T : struct, System.Enum
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{
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if (!IsValid(value))
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throw new InvalidEnumArgumentException(argName ?? "value", Convert.ToInt32(value), typeof(T));
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}
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/// <summary>Clears the specified flags from an enumerated value and returns the new value.</summary>
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/// <typeparam name="T">The enumerated type.</typeparam>
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/// <param name="flags">The enumerated value.</param>
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/// <param name="flag">The flags to clear or unset.</param>
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/// <returns>The resulting enumerated value after the <paramref name="flag"/> has been unset.</returns>
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public static T ClearFlags<T>(this T flags, T flag) where T : struct, System.Enum => flags.SetFlags(flag, false);
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/// <summary>Combines enumerated list of values into a single enumerated value.</summary>
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/// <typeparam name="T">The enumerated type.</typeparam>
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/// <param name="flags">The flags to combine.</param>
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/// <returns>A single enumerated value.</returns>
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public static T CombineFlags<T>(this IEnumerable<T> flags) where T : struct, System.Enum
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{
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CheckHasFlags<T>();
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long lValue = 0;
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foreach (var flag in flags)
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{
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var lFlag = Convert.ToInt64(flag);
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lValue |= lFlag;
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}
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return (T)Enum.ToObject(typeof(T), lValue);
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}
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/// <summary>Gets the description supplied by a <see cref="DescriptionAttribute"/> if one is set.</summary>
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/// <typeparam name="T">The enumerated type.</typeparam>
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/// <param name="value">The enumerated value.</param>
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/// <returns>The description, or <c>null</c> if one is not set.</returns>
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public static string GetDescription<T>(this T value) where T : struct, System.Enum
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{
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// If this is flag, return flags if there are more than one.
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if (IsFlags<T>() && value.GetFlags().Count() > 1)
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return value.ToString();
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// Get the name or description of the single enum value.
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var name = Enum.GetName(typeof(T), value);
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if (name != null)
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{
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var field = typeof(T).GetField(name);
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if (field != null && Attribute.GetCustomAttribute(field, typeof(DescriptionAttribute)) is DescriptionAttribute attr)
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return attr.Description;
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}
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return name;
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}
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/// <summary>Gets the flags of an enumerated value as an enumerated list.</summary>
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/// <typeparam name="T">The enumerated type.</typeparam>
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/// <param name="value">The enumerated value.</param>
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/// <returns>An enumeration of individual flags that compose the <paramref name="value"/>.</returns>
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public static IEnumerable<T> GetFlags<T>(this T value) where T : struct, System.Enum
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{
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CheckHasFlags<T>();
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foreach (T flag in Enum.GetValues(typeof(T)))
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{
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if (value.IsFlagSet(flag))
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yield return flag;
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}
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}
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/// <summary>Determines whether the enumerated flag value has the specified flag set.</summary>
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/// <typeparam name="T">The enumerated type.</typeparam>
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/// <param name="flags">The enumerated flag value.</param>
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/// <param name="flag">The flag value to check.</param>
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/// <returns><c>true</c> if is flag set; otherwise, <c>false</c>.</returns>
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public static bool IsFlagSet<T>(this T flags, T flag) where T : struct, System.Enum
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{
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CheckHasFlags<T>();
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var flagValue = Convert.ToInt64(flag);
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return (Convert.ToInt64(flags) & flagValue) == flagValue;
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}
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/// <summary>Returns an indication if the enumerated value is either defined or can be defined by a set of known flags.</summary>
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/// <typeparam name="T">The enumerated type.</typeparam>
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/// <param name="value">The enumerated value.</param>
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/// <returns><c>true</c> if the specified value is valid; otherwise, <c>false</c>.</returns>
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public static bool IsValid<T>(this T value) where T : struct, System.Enum
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{
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if (IsFlags<T>())
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{
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long mask = 0, lValue = Convert.ToInt64(value);
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foreach (T flag in Enum.GetValues(typeof(T)))
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mask |= Convert.ToInt64(flag);
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return (mask & lValue) == lValue;
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}
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return Enum.IsDefined(typeof(T), value);
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}
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/// <summary>Set or unsets flags in a referenced enumerated value.</summary>
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/// <typeparam name="T">The enumerated type.</typeparam>
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/// <param name="flags">A reference to an enumerated value.</param>
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/// <param name="flag">The flag to set or unset.</param>
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/// <param name="set">if set to <c>true</c> sets the flag; otherwise the flag is unset.</param>
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public static void SetFlags<T>(ref T flags, T flag, bool set = true) where T : struct, System.Enum
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{
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CheckHasFlags<T>();
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var flagsValue = Convert.ToInt64(flags);
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var flagValue = Convert.ToInt64(flag);
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if (set)
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flagsValue |= flagValue;
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else
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flagsValue &= (~flagValue);
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flags = (T)Enum.ToObject(typeof(T), flagsValue);
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}
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/// <summary>Set or unsets flags in an enumerated value and returns the new value.</summary>
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/// <typeparam name="T">The enumerated type.</typeparam>
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/// <param name="flags">The enumerated value.</param>
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/// <param name="flag">The flag to set or unset.</param>
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/// <param name="set">if set to <c>true</c> sets the flag; otherwise the flag is unset.</param>
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/// <returns>The resulting enumerated value after the <paramref name="flag"/> has been set or unset.</returns>
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public static T SetFlags<T>(this T flags, T flag, bool set = true) where T : struct, System.Enum
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{
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var ret = flags;
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SetFlags(ref ret, flag, set);
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return ret;
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}
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/// <summary>Converts an enumerated value to another fixed type.</summary>
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/// <typeparam name="TEnum">The enumerated type.</typeparam>
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/// <typeparam name="TResult">The type of the result.</typeparam>
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/// <param name="value">The value to convert.</param>
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/// <returns>The converted value.</returns>
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/// <exception cref="System.ArgumentException">The size of TResult cannot be smaller than the size of TEnum.</exception>
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public static TResult To<TEnum, TResult>(this TEnum value) where TEnum : unmanaged, System.Enum where TResult : unmanaged, IConvertible
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{
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unsafe
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{
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if (sizeof(TResult) < sizeof(TEnum)) throw new ArgumentException("The size of TResult cannot be smaller than the size of TEnum.");
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return *(TResult*)(void*)&value;
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}
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}
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/// <summary>Converts a fixed type to an enumerated value.</summary>
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/// <typeparam name="TValue">The type of the value to convert.</typeparam>
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/// <typeparam name="TEnum">The enumerated type.</typeparam>
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/// <param name="value">The value to convert.</param>
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/// <returns>The converted value.</returns>
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/// <exception cref="System.ArgumentException">The size of TEnum cannot be smaller than the size of TValue.</exception>
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public static TEnum ToEnum<TValue, TEnum>(this TValue value) where TEnum : unmanaged, System.Enum where TValue : unmanaged, IConvertible
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{
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unsafe
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{
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if (sizeof(TEnum) < sizeof(TValue)) throw new ArgumentException("The size of TEnum cannot be smaller than the size of TValue.");
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return *(TEnum*)(void*)&value;
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}
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}
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/// <summary>Converts a fixed type to an enumerated value.</summary>
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/// <typeparam name="TEnum">The enumerated type.</typeparam>
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/// <param name="value">The value to convert.</param>
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/// <returns>The converted value.</returns>
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public static TEnum ToEnum<TEnum>(this byte value) where TEnum : unmanaged, System.Enum => ToEnum<byte, TEnum>(value);
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/// <summary>Converts a fixed type to an enumerated value.</summary>
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/// <typeparam name="TEnum">The enumerated type.</typeparam>
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/// <param name="value">The value to convert.</param>
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/// <returns>The converted value.</returns>
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public static TEnum ToEnum<TEnum>(this sbyte value) where TEnum : unmanaged, System.Enum => ToEnum<sbyte, TEnum>(value);
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/// <summary>Converts a fixed type to an enumerated value.</summary>
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/// <typeparam name="TEnum">The enumerated type.</typeparam>
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/// <param name="value">The value to convert.</param>
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/// <returns>The converted value.</returns>
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public static TEnum ToEnum<TEnum>(this ushort value) where TEnum : unmanaged, System.Enum => ToEnum<ushort, TEnum>(value);
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/// <summary>Converts a fixed type to an enumerated value.</summary>
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/// <typeparam name="TEnum">The enumerated type.</typeparam>
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/// <param name="value">The value to convert.</param>
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/// <returns>The converted value.</returns>
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public static TEnum ToEnum<TEnum>(this short value) where TEnum : unmanaged, System.Enum => ToEnum<short, TEnum>(value);
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/// <summary>Converts a fixed type to an enumerated value.</summary>
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/// <typeparam name="TEnum">The enumerated type.</typeparam>
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/// <param name="value">The value to convert.</param>
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/// <returns>The converted value.</returns>
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public static TEnum ToEnum<TEnum>(this uint value) where TEnum : unmanaged, System.Enum => ToEnum<uint, TEnum>(value);
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/// <summary>Converts a fixed type to an enumerated value.</summary>
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/// <typeparam name="TEnum">The enumerated type.</typeparam>
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/// <param name="value">The value to convert.</param>
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/// <returns>The converted value.</returns>
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public static TEnum ToEnum<TEnum>(this int value) where TEnum : unmanaged, System.Enum => ToEnum<int, TEnum>(value);
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/// <summary>Checks if <typeparamref name="T"/> represents an enumeration and throws an exception if not.</summary>
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/// <typeparam name="T">The <see cref="Type"/> to validate.</typeparam>
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/// <exception cref="System.ArgumentException"></exception>
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private static void CheckHasFlags<T>() where T : struct, System.Enum
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{
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if (!IsFlags<T>())
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throw new ArgumentException($"Type '{typeof(T).FullName}' doesn't have the 'Flags' attribute");
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}
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/// <summary>Determines whether this enumerations has the <see cref="FlagsAttribute"/> set.</summary>
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/// <typeparam name="T">The enumerated type.</typeparam>
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/// <returns><c>true</c> if this instance has the <see cref="FlagsAttribute"/> set; otherwise, <c>false</c>.</returns>
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private static bool IsFlags<T>() where T : struct, System.Enum => Attribute.IsDefined(typeof(T), typeof(FlagsAttribute));
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/*/// <summary>Returns an indication if the enumerated value is either defined or can be defined by a set of known flags.</summary>
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/// <typeparam name="T">The enumerated type.</typeparam>
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/// <param name="value">The enumerated value.</param>
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/// <param name="validValues">The valid values.</param>
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/// <returns><c>true</c> if the specified value is valid; otherwise, <c>false</c>.</returns>
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private static bool IsValid<T>(this T value, params T[] validValues) where T : struct, IConvertible
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{
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CheckIsEnum<T>();
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foreach (var vval in validValues)
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if (value.Equals(vval))
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return true;
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return false;
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}*/
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}
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} |