BusinessCats.Ascii85.DecodeData C# (CSharp) Метод

        public byte[] DecodeData(string s)
        {
            if (EnforceMarks)
            {
                if (!s.StartsWith(PrefixMark) | !s.EndsWith(SuffixMark))
                {
                    throw new Exception("ASCII85 encoded data should begin with '" + PrefixMark +
                        "' and end with '" + SuffixMark + "'");
                }
            }

            // strip prefix and suffix if present
            if (s.StartsWith(PrefixMark))
            {
                s = s.Substring(PrefixMark.Length);
            }
            if (s.EndsWith(SuffixMark))
            {
                s = s.Substring(0, s.Length - SuffixMark.Length);
            }

            MemoryStream ms = new MemoryStream();
            int count = 0;
            bool processChar = false;

            foreach (char c in s)
            {
                switch (c)
                {
                    case 'z':
                        if (count != 0)
                        {
                            throw new Exception("The character 'z' is invalid inside an ASCII85 block.");
                        }
                        _decodedBlock[0] = 0;
                        _decodedBlock[1] = 0;
                        _decodedBlock[2] = 0;
                        _decodedBlock[3] = 0;
                        ms.Write(_decodedBlock, 0, _decodedBlock.Length);
                        processChar = false;
                        break;
                    case '\n':
                    case '\r':
                    case '\t':
                    case '\0':
                    case '\f':
                    case '\b':
                        processChar = false;
                        break;
                    default:
                        if (c < '!' || c > 'u')
                        {
                            throw new Exception("Bad character '" + c + "' found. ASCII85 only allows characters '!' to 'u'.");
                        }
                        processChar = true;
                        break;
                }

                if (processChar)
                {
                    _tuple += ((uint)(c - _asciiOffset) * pow85[count]);
                    count++;
                    if (count == _encodedBlock.Length)
                    {
                        DecodeBlock();
                        ms.Write(_decodedBlock, 0, _decodedBlock.Length);
                        _tuple = 0;
                        count = 0;
                    }
                }
            }

            // if we have some bytes left over at the end..
            if (count != 0)
            {
                if (count == 1)
                {
                    throw new Exception("The last block of ASCII85 data cannot be a single byte.");
                }
                count--;
                _tuple += pow85[count];
                DecodeBlock(count);
                for (int i = 0; i < count; i++)
                {
                    ms.WriteByte(_decodedBlock[i]);
                }
            }

            return ms.ToArray();
        }