HLib/Commons/EncodingUxer.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace KssSmaPlaLib.Commons
{
    public class EncodingUxer
    {
        #region 列挙体

        public enum EncodingType
        {
            Utf8WithBom,
            Utf8WithoutBom,
            ShiftJIS
        }

        #endregion

        public static Encoding GetEncoding(EncodingType type)
        {
            switch (type)
            {
                case EncodingType.Utf8WithBom:
                    return new UTF8Encoding(encoderShouldEmitUTF8Identifier: true); // BOMあり
                case EncodingType.Utf8WithoutBom:
                    return new UTF8Encoding(encoderShouldEmitUTF8Identifier: false); // BOMなし
                case EncodingType.ShiftJIS:
                    return Encoding.GetEncoding("shift_jis"); // ANSI（Windows-932）
                default:
                    throw new ArgumentOutOfRangeException(nameof(type), "未対応のエンコーディングです");
            }
        }

        public static EncodingType? GetEncodingType(string typeString)
        {
            typeString = typeString.ToLower();

            if (StringUxer.WildcardMatch(typeString, "*utf*8*without*bom*"))
                return EncodingType.Utf8WithoutBom;
            if (StringUxer.WildcardMatch(typeString, "*utf*8*with*bom*"))
                return EncodingType.Utf8WithBom;
            if (StringUxer.WildcardMatch(typeString, "*utf*8*"))
                return EncodingType.Utf8WithoutBom;
            if (StringUxer.WildcardMatch(typeString, "*s*jis*"))
                return EncodingType.ShiftJIS;
            if (StringUxer.WildcardMatch(typeString, "*シ*jis*"))
                return EncodingType.ShiftJIS;
            return null;
        }
    }
}