view Implab/Automaton/EnumAlphabet.cs @ 196:40d7fed4a09e

fixed promise chaining behavior, the error handler doesn't handle result or cancellation handlers exceptions these exceptions are propagated to the next handlers.
author cin
date Mon, 29 Aug 2016 23:15:51 +0300
parents c32688129f14
children
line wrap: on
line source

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Globalization;
using System.Linq;
using System.Diagnostics.CodeAnalysis;

namespace Implab.Automaton {
    /// <summary>
    /// Алфавит символами которого являются элементы перечислений.
    /// </summary>
    /// <typeparam name="T">Тип перечислений</typeparam>
    public class EnumAlphabet<T> : IndexedAlphabetBase<T> where T : struct, IConvertible {
        [SuppressMessage("Microsoft.Design", "CA1000:DoNotDeclareStaticMembersOnGenericTypes")]
        static readonly Lazy<T[]> _symbols = new Lazy<T[]>(GetSymbols);

        [SuppressMessage("Microsoft.Design", "CA1000:DoNotDeclareStaticMembersOnGenericTypes")]
        static readonly Lazy<EnumAlphabet<T>> _fullAlphabet = new Lazy<EnumAlphabet<T>>(CreateEnumAlphabet);

        static EnumAlphabet<T> CreateEnumAlphabet() {
            var symbols = _symbols.Value;

            if (
                symbols[symbols.Length - 1].ToInt32(CultureInfo.InvariantCulture) >= symbols.Length
                || symbols[0].ToInt32(CultureInfo.InvariantCulture) != 0
            )
                throw new InvalidOperationException("The specified enumeration must be zero-based and continuously numbered");

            return new EnumAlphabet<T>(symbols.Select(x => x.ToInt32(CultureInfo.InvariantCulture)).ToArray());
        }

        static T[] GetSymbols() {
            if (!typeof(T).IsEnum)
                throw new InvalidOperationException("Invalid generic parameter, enumeration is required");

            if (Enum.GetUnderlyingType(typeof(T)) != typeof(Int32))
                throw new InvalidOperationException("Only enums based on Int32 are supported");
            
            return ((T[])Enum.GetValues(typeof(T)))
                .OrderBy(x => x.ToInt32(CultureInfo.InvariantCulture))
                .ToArray();
        }

        public static EnumAlphabet<T> FullAlphabet {
            get {
                return _fullAlphabet.Value;
            }
        }


        public EnumAlphabet()
            : base(_symbols.Value.Length) {
        }

        public EnumAlphabet(int[] map)
            : base(map) {
            Debug.Assert(map.Length == _symbols.Value.Length);
        }


        public override int GetSymbolIndex(T symbol) {
            return symbol.ToInt32(CultureInfo.InvariantCulture);
        }

    }
}