public PrepareResult PrepareCommand(string input, out Statement statement)
{
statement = new Statement();
if (input.Substring(0, 4).Equals("Save", StringComparison.OrdinalIgnoreCase))
{
statement.StatementType = StatementType_T.STATEMENT_SAVE;
}
else if (input.Substring(0, 6).Equals("insert", StringComparison.OrdinalIgnoreCase))
{
statement.StatementType = StatementType_T.STATEMENT_INSERT;
input = input.Trim();
var list = input.Split(new string[] { " " }, StringSplitOptions.RemoveEmptyEntries);
if (list.Length != 4)
{
return(PrepareResult.PREPARE_SYNTAX_ERROR);
}
UserRow row = new UserRow();
row.id = int.Parse(list[1]);
row.username = list[2];
row.email = list[3];
statement.Row = row;
}
else if (input.Substring(0, 6).Equals("select", StringComparison.OrdinalIgnoreCase))
{
statement.StatementType = StatementType_T.STATEMENT_SELECT;
}
return(PrepareResult.PREPARE_SUCCESS);
}
public static UserRow DeSerialize(byte[] bytes)
{
UserRow user = new UserRow();
user.id = BitConverter.ToInt32(bytes, 0);
user.username = Encoding.ASCII.GetString(bytes, 4, 32).Trim('\0');
user.email = Encoding.ASCII.GetString(bytes, 36, 255).Trim('\0');
return(user);
}
public void CursorValue(out byte[] page, out int offset)
{
UserRow userRow = new UserRow();
var pageNumber = this.RowNumber / userRow.RowPerPage;
var rowNumberInPage = this.RowNumber % userRow.RowPerPage;
page = this.Table.Pager.GetPage(pageNumber);
offset = rowNumberInPage * userRow.RowSize;
}
public static UserRow[] Select()
{
UserRow[] result = new UserRow[MaxRowNumber];
Console.WriteLine("Count:" + (MaxRowNumber + 1));
Console.WriteLine("id\tusername\temail");
for (int i = 0; i < MaxRowNumber; i++)
{
var pageNumber = i / UserRow.RowPerPage;
var rowNumberInPage = i % UserRow.RowPerPage;
var offset = rowNumberInPage * UserRow.RowSize;
byte[] rowData = new byte[UserRow.RowSize];
Array.Copy(Pages[pageNumber], offset, rowData, 0, UserRow.RowSize);
var row = UserRow.DeSerialize(rowData);
Console.WriteLine($"{row.id}\t{row.username}\t{row.email}");
result[i] = row;
}
return(result);
}
public static void Insert(UserRow row)
{
if (MaxRowNumber >= TableMaxRows)
{
Console.WriteLine("Table Full");
return;
}
var bytes = row.Serialize();
var pageNumber = MaxRowNumber / UserRow.RowPerPage;
var rowNumberInPage = MaxRowNumber % UserRow.RowPerPage;
var offset = rowNumberInPage * UserRow.RowSize;
if (Pages[pageNumber] == null)
{
Pages[pageNumber] = new byte[PageSize];
MaxPage = pageNumber;
}
Array.Copy(bytes, 0, Pages[pageNumber], offset, UserRow.RowSize);
MaxRowNumber++;
}
