System.Data.SqlClient.TdsParser.ReadPlpAnsiChars C# (CSharp) Method

        internal int ReadPlpAnsiChars(ref char[] buff, int offst, int len, SqlMetaDataPriv metadata, TdsParserStateObject stateObj)
        {
            int charsRead = 0;
            int charsLeft = 0;
            int bytesRead = 0;
            int totalcharsRead = 0;

            if (stateObj._longlen == 0)
            {
                Debug.Assert(stateObj._longlenleft == 0);
                return 0;       // No data
            }

            Debug.Assert(((ulong)stateObj._longlen != TdsEnums.SQL_PLP_NULL),
                    "Out of sync plp read request");

            Debug.Assert((buff == null && offst == 0) || (buff.Length >= offst + len), "Invalid length sent to ReadPlpAnsiChars()!");
            charsLeft = len;

            if (stateObj._longlenleft == 0)
            {
                stateObj.ReadPlpLength(false);
                if (stateObj._longlenleft == 0)
                {// Data read complete
                    stateObj._plpdecoder = null;
                    return 0;
                }
            }

            if (stateObj._plpdecoder == null)
            {
                Encoding enc = metadata.encoding;

                if (enc == null)
                {
                    if (null == _defaultEncoding)
                    {
                        ThrowUnsupportedCollationEncountered(stateObj);
                    }

                    enc = _defaultEncoding;
                }
                stateObj._plpdecoder = enc.GetDecoder();
            }

            while (charsLeft > 0)
            {
                bytesRead = (int)Math.Min(stateObj._longlenleft, (ulong)charsLeft);
                if ((stateObj._bTmp == null) || (stateObj._bTmp.Length < bytesRead))
                {
                    // Grow the array
                    stateObj._bTmp = new byte[bytesRead];
                }

                bytesRead = stateObj.ReadPlpBytesChunk(stateObj._bTmp, 0, bytesRead);

                charsRead = stateObj._plpdecoder.GetChars(stateObj._bTmp, 0, bytesRead, buff, offst);
                charsLeft -= charsRead;
                offst += charsRead;
                totalcharsRead += charsRead;
                if (stateObj._longlenleft == 0)  // Read the next chunk or cleanup state if hit the end
                    stateObj.ReadPlpLength(false);

                if (stateObj._longlenleft == 0)
                { // Data read complete
                    stateObj._plpdecoder = null;
                    break;
                }
            }
            return (totalcharsRead);
        }