OEM encoding C#

OemEncoding.cs

using System.Linq;
using System.Text;


    class OemEncoding : Encoding
    {
        private static readonly char[] Oem =
            new[]
            {
                127, 199, 252, 233, 226, 228, 224, 229, 231, 234, 235, 232, 239, 238, 236, 196, 197, 201, 230, 198, 244,
                246, 242, 251, 249, 255, 214, 220, 162, 163, 165, 8359, 402, 225, 237, 243, 250, 241, 209, 170, 186, 191,
                8976, 172, 189, 188, 161, 171, 187, 9617, 9618, 9619, 9474, 9508, 9569, 9570, 9558, 9557, 9571, 9553,
                9559, 9565, 9564, 9563, 9488, 9492, 9524, 9516, 9500, 9472, 9532, 9566, 9567, 9562, 9556, 9577, 9574,
                9568, 9552, 9580, 9575, 9576, 9572, 9573, 9561, 9560, 9554, 9555, 9579, 9578, 9496, 9484, 9608, 9604,
                9612, 9616, 9600, 945, 223, 915, 960, 931, 963, 181, 964, 934, 920, 937, 948, 8734, 966, 949, 8745, 8801,
                177, 8805, 8804, 8992, 8993, 247, 8776, 176, 8729, 183, 8730, 8319, 178, 9632, 160
            }.Select(x => ((char) x)).ToArray();

        private static readonly char[] OemToChar = new char[byte.MaxValue + 1];
        private static readonly byte[] CharToOem = new byte[char.MaxValue + 1];

        static OemEncoding()
        {
            for (var i = 0; i <= byte.MaxValue; i++)
            {
                var b = (byte) i;
                if (b < 0x20)
                    OemToChar[b] = ' ';
                else if (b >= 127)
                    OemToChar[b] = Oem[b - 127];
                else
                    OemToChar[b] = (char) b;
            }
            for (var i = 0; i <= char.MaxValue; i++)
            {
                var c = (char) i;
                if (c < 127)
                    CharToOem[c] = (byte) c;
                else
                    CharToOem[c] = (byte)'?';
            }
            for (var i = 0; i < Oem.Length; i++)
                CharToOem[Oem[i]] = (byte) i;
        }

        public override string BodyName => "OEM";
        public override string EncodingName => "OEM";
        public override int CodePage => 437;

        public override int GetByteCount(char[] chars, int index, int count)
        {
            return count;
        }

        public override int GetBytes(char[] chars, int charIndex, int charCount, byte[] bytes, int byteIndex)
        {
            for (var c = 0; c < charCount; c++)
                bytes[byteIndex + c] = CharToOem[chars[charIndex + c]];
            return charCount;
        }

        public override int GetCharCount(byte[] bytes, int index, int count)
        {
            return count;
        }

        public override int GetChars(byte[] bytes, int byteIndex, int byteCount, char[] chars, int charIndex)
        {
            for (var c = 0; c < byteCount; c++)
                chars[charIndex + c] = OemToChar[bytes[byteIndex + c]];
            return byteCount;
        }

        public override int GetMaxByteCount(int charCount)
        {
            return charCount;
        }

        public override int GetMaxCharCount(int byteCount)
        {
            return byteCount;
        }
    }