System.Data.SqlClient.TdsParser.TryReadPlpUnicodeChars C# (CSharp) Метод

        internal bool TryReadPlpUnicodeChars(ref char[] buff, int offst, int len, TdsParserStateObject stateObj, out int totalCharsRead)
        {
            int charsRead = 0;
            int charsLeft = 0;
            char[] newbuf;

            if (stateObj._longlen == 0)
            {
                Debug.Assert(stateObj._longlenleft == 0);
                totalCharsRead = 0;
                return true;       // 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 ReadPlpUnicodeChars()!");
            charsLeft = len;

            // If total length is known up front, allocate the whole buffer in one shot instead of realloc'ing and copying over each time
            if (buff == null && stateObj._longlen != TdsEnums.SQL_PLP_UNKNOWNLEN)
            {
                buff = new char[(int)Math.Min((int)stateObj._longlen, len)];
            }

            if (stateObj._longlenleft == 0)
            {
                ulong ignored;
                if (!stateObj.TryReadPlpLength(false, out ignored))
                {
                    totalCharsRead = 0;
                    return false;
                }
                if (stateObj._longlenleft == 0)
                { // Data read complete
                    totalCharsRead = 0;
                    return true;
                }
            }

            totalCharsRead = 0;

            while (charsLeft > 0)
            {
                charsRead = (int)Math.Min((stateObj._longlenleft + 1) >> 1, (ulong)charsLeft);
                if ((buff == null) || (buff.Length < (offst + charsRead)))
                {
                    // Grow the array
                    newbuf = new char[offst + charsRead];
                    if (buff != null)
                    {
                        Buffer.BlockCopy(buff, 0, newbuf, 0, offst * 2);
                    }
                    buff = newbuf;
                }
                if (charsRead > 0)
                {
                    if (!TryReadPlpUnicodeCharsChunk(buff, offst, charsRead, stateObj, out charsRead))
                    {
                        return false;
                    }
                    charsLeft -= charsRead;
                    offst += charsRead;
                    totalCharsRead += charsRead;
                }
                // Special case single byte left
                if (stateObj._longlenleft == 1 && (charsLeft > 0))
                {
                    byte b1;
                    if (!stateObj.TryReadByte(out b1))
                    {
                        return false;
                    }
                    stateObj._longlenleft--;
                    ulong ignored;
                    if (!stateObj.TryReadPlpLength(false, out ignored))
                    {
                        return false;
                    }
                    Debug.Assert((stateObj._longlenleft != 0), "ReadPlpUnicodeChars: Odd byte left at the end!");
                    byte b2;
                    if (!stateObj.TryReadByte(out b2))
                    {
                        return false;
                    }
                    stateObj._longlenleft--;
                    // Put it at the end of the array. At this point we know we have an extra byte.
                    buff[offst] = (char)(((b2 & 0xff) << 8) + (b1 & 0xff));
                    offst = checked((int)offst + 1);
                    charsRead++;
                    charsLeft--;
                    totalCharsRead++;
                }
                if (stateObj._longlenleft == 0)
                { // Read the next chunk or cleanup state if hit the end
                    ulong ignored;
                    if (!stateObj.TryReadPlpLength(false, out ignored))
                    {
                        return false;
                    }
                }

                if (stateObj._longlenleft == 0)   // Data read complete
                    break;
            }
            return true;
        }