public long GetChars(DataRowMessage row, int charOffset, char[] output, int outputOffset, int charsCount, FieldDescription field)
{
if (row.PosInColumn == 0)
{
_charPos = 0;
}
if (output == null)
{
// Note: Getting the length of a text column means decoding the entire field,
// very inefficient and also consumes the column in sequential mode. But this seems to
// be SqlClient's behavior as well.
int bytesSkipped, charsSkipped;
row.Buffer.SkipChars(int.MaxValue, row.ColumnLen - row.PosInColumn, out bytesSkipped, out charsSkipped);
Contract.Assume(bytesSkipped == row.ColumnLen - row.PosInColumn);
row.PosInColumn += bytesSkipped;
_charPos += charsSkipped;
return(_charPos);
}
if (charOffset < _charPos)
{
row.SeekInColumn(0);
_charPos = 0;
}
if (charOffset > _charPos)
{
var charsToSkip = charOffset - _charPos;
int bytesSkipped, charsSkipped;
row.Buffer.SkipChars(charsToSkip, row.ColumnLen - row.PosInColumn, out bytesSkipped, out charsSkipped);
row.PosInColumn += bytesSkipped;
_charPos += charsSkipped;
if (charsSkipped < charsToSkip)
{
// TODO: What is the actual required behavior here?
throw new IndexOutOfRangeException();
}
}
int bytesRead, charsRead;
row.Buffer.ReadChars(output, outputOffset, charsCount, row.ColumnLen - row.PosInColumn, out bytesRead, out charsRead);
row.PosInColumn += bytesRead;
_charPos += charsRead;
return(charsRead);
}
public long GetBytes(DataRowMessage row, int offset, [CanBeNull] byte[] output, int outputOffset, int len, FieldDescription field)
{
if (output == null)
{
return(row.ColumnLen);
}
row.SeekInColumn(offset);
// Attempt to read beyond the end of the column
if (offset + len > row.ColumnLen)
{
len = row.ColumnLen - offset;
}
row.Buffer.ReadAllBytes(output, outputOffset, len, false);
row.PosInColumn += len;
return(len);
}