Newtonsoft.Json\Utilities\EnumUtils.cs

#region License

// Copyright (c) 2007 James Newton-King

//

// Permission is hereby granted, free of charge, to any person

// obtaining a copy of this software and associated documentation

// files (the "Software"), to deal in the Software without

// restriction, including without limitation the rights to use,

// copy, modify, merge, publish, distribute, sublicense, and/or sell

// copies of the Software, and to permit persons to whom the

// Software is furnished to do so, subject to the following

// conditions:

//

// The above copyright notice and this permission notice shall be

// included in all copies or substantial portions of the Software.

//

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES

// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND

// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT

// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,

// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR

// OTHER DEALINGS IN THE SOFTWARE.

#endregion

using System;

using System.Collections.Generic;

using System.Globalization;

using System.Linq;

using System.Reflection;

namespace Newtonsoft.Json.Utilities

{

  internal static class EnumUtils

  {

    /// <summary>

    /// Parses the specified enum member name, returning it's value.

    /// </summary>

    /// <param name="enumMemberName">Name of the enum member.</param>

    /// <returns></returns>

    public static T Parse<T>(string enumMemberName) where T : struct

    {

      return Parse<T>(enumMemberName, false);

    }

    /// <summary>

    /// Parses the specified enum member name, returning it's value.

    /// </summary>

    /// <param name="enumMemberName">Name of the enum member.</param>

    /// <param name="ignoreCase">If set to <c>true</c> ignore case.</param>

    /// <returns></returns>

    public static T Parse<T>(string enumMemberName, bool ignoreCase) where T : struct

    {

      ValidationUtils.ArgumentTypeIsEnum(typeof(T), "T");

      return (T)Enum.Parse(typeof(T), enumMemberName, ignoreCase);

    }

    public static bool TryParse<T>(string enumMemberName, bool ignoreCase, out T value) where T : struct

    {

      ValidationUtils.ArgumentTypeIsEnum(typeof(T), "T");

      return MiscellaneousUtils.TryAction(() => Parse<T>(enumMemberName, ignoreCase), out value);

    }

    public static IList<T> GetFlagsValues<T>(T value) where T : struct

    {

      Type enumType = typeof(T);

      if (!enumType.IsDefined(typeof(FlagsAttribute), false))

        throw new Exception("Enum type {0} is not a set of flags.".FormatWith(CultureInfo.InvariantCulture, enumType));

      Type underlyingType = Enum.GetUnderlyingType(value.GetType());

      ulong num = Convert.ToUInt64(value, CultureInfo.InvariantCulture);

      EnumValues<ulong> enumNameValues = GetNamesAndValues<T>();

      IList<T> selectedFlagsValues = new List<T>();

      foreach (EnumValue<ulong> enumNameValue in enumNameValues)

      {

        if ((num & enumNameValue.Value) == enumNameValue.Value && enumNameValue.Value != 0)

          selectedFlagsValues.Add((T)Convert.ChangeType(enumNameValue.Value, underlyingType, CultureInfo.CurrentCulture));

      }

      if (selectedFlagsValues.Count == 0 && enumNameValues.SingleOrDefault(v => v.Value == 0) != null)

        selectedFlagsValues.Add(default(T));

      return selectedFlagsValues;

    }

    /// <summary>

    /// Gets a dictionary of the names and values of an Enum type.

    /// </summary>

    /// <returns></returns>

    public static EnumValues<ulong> GetNamesAndValues<T>() where T : struct

    {

      return GetNamesAndValues<ulong>(typeof(T));

    }

    /// <summary>

    /// Gets a dictionary of the names and values of an Enum type.

    /// </summary>

    /// <returns></returns>

    public static EnumValues<TUnderlyingType> GetNamesAndValues<TEnum, TUnderlyingType>()

      where TEnum : struct

      where TUnderlyingType : struct

    {

      return GetNamesAndValues<TUnderlyingType>(typeof(TEnum));

    }

    /// <summary>

    /// Gets a dictionary of the names and values of an Enum type.

    /// </summary>

    /// <param name="enumType">The enum type to get names and values for.</param>

    /// <returns></returns>

    public static EnumValues<TUnderlyingType> GetNamesAndValues<TUnderlyingType>(Type enumType) where TUnderlyingType : struct

    {

      if (enumType == null)

        throw new ArgumentNullException("enumType");

      ValidationUtils.ArgumentTypeIsEnum(enumType, "enumType");

      IList<object> enumValues = GetValues(enumType);

      IList<string> enumNames = GetNames(enumType);

      EnumValues<TUnderlyingType> nameValues = new EnumValues<TUnderlyingType>();

      for (int i = 0; i < enumValues.Count; i++)

      {

        try

        {

          nameValues.Add(new EnumValue<TUnderlyingType>(enumNames[i], (TUnderlyingType)Convert.ChangeType(enumValues[i], typeof(TUnderlyingType), CultureInfo.CurrentCulture)));

        }

        catch (OverflowException e)

        {

          throw new Exception(

            string.Format(CultureInfo.InvariantCulture, "Value from enum with the underlying type of {0} cannot be added to dictionary with a value type of {1}. Value was too large: {2}",

              Enum.GetUnderlyingType(enumType), typeof(TUnderlyingType), Convert.ToUInt64(enumValues[i], CultureInfo.InvariantCulture)), e);

        }

      }

      return nameValues;

    }

    public static IList<T> GetValues<T>()

    {

      return GetValues(typeof(T)).Cast<T>().ToList();

    }

    public static IList<object> GetValues(Type enumType)

    {

      if (!enumType.IsEnum)

        throw new ArgumentException("Type '" + enumType.Name + "' is not an enum.");

      List<object> values = new List<object>();

      var fields = from field in enumType.GetFields()

                   where field.IsLiteral

                   select field;

      foreach (FieldInfo field in fields)

      {

        object value = field.GetValue(enumType);

        values.Add(value);

      }

      return values;

    }

    public static IList<string> GetNames<T>()

    {

      return GetNames(typeof(T));

    }

    public static IList<string> GetNames(Type enumType)

    {

      if (!enumType.IsEnum)

        throw new ArgumentException("Type '" + enumType.Name + "' is not an enum.");

      List<string> values = new List<string>();

      var fields = from field in enumType.GetFields()

                   where field.IsLiteral

                   select field;

      foreach (FieldInfo field in fields)

      {

        values.Add(field.Name);

      }

      return values;

    }

    /// <summary>

    /// Gets the maximum valid value of an Enum type. Flags enums are ORed.

    /// </summary>

    /// <typeparam name="TEnumType">The type of the returned value. Must be assignable from the enum's underlying value type.</typeparam>

    /// <param name="enumType">The enum type to get the maximum value for.</param>

    /// <returns></returns>

    public static TEnumType GetMaximumValue<TEnumType>(Type enumType) where TEnumType : IConvertible, IComparable<TEnumType>

    {

      if (enumType == null)

        throw new ArgumentNullException("enumType");

      Type enumUnderlyingType = Enum.GetUnderlyingType(enumType);

      if (!typeof(TEnumType).IsAssignableFrom(enumUnderlyingType))

        throw new ArgumentException(string.Format(CultureInfo.InvariantCulture, "TEnumType is not assignable from the enum's underlying type of {0}.", enumUnderlyingType.Name));

      ulong maximumValue = 0;

      IList<object> enumValues = GetValues(enumType);

      if (enumType.IsDefined(typeof(FlagsAttribute), false))

      {

        foreach (TEnumType value in enumValues)

        {

          maximumValue = maximumValue | value.ToUInt64(CultureInfo.InvariantCulture);

        }

      }

      else

      {

        foreach (TEnumType value in enumValues)

        {

          ulong tempValue = value.ToUInt64(CultureInfo.InvariantCulture);

          // maximumValue is smaller than the enum value

          if (maximumValue.CompareTo(tempValue) == -1)

            maximumValue = tempValue;

        }

      }

      return (TEnumType)Convert.ChangeType(maximumValue, typeof(TEnumType), CultureInfo.InvariantCulture);

    }

  }

}