/// <summary>
/// Gets or sets specified data column value.
/// </summary>
/// <param name="columnIndex">Zero based column index.</param>
/// <returns></returns>
public object this[int columnIndex]
{
/* Fixed record structure:
* 1 byte - specified is row is used or free space
* u - used
* f - free space
* x bytes - columns data
* 2 bytes - CRLF
*/
get{
if (columnIndex < 0)
{
throw new Exception("The columnIndex can't be negative value !");
}
if (columnIndex > m_ColumnCount)
{
throw new Exception("The columnIndex out of columns count !");
}
return(ConvertFromInternalData(m_ColumnDataTypes[columnIndex], m_RowData, m_ColumnDataStartOffsets[columnIndex], m_ColumnDataSizes[columnIndex]));
}
set{
if (columnIndex < 0)
{
throw new Exception("The columnIndex can't be negative value !");
}
if (columnIndex > m_ColumnCount)
{
throw new Exception("The columnIndex out of columns count !");
}
byte[] val = LDB_Record.ConvertToInternalData(m_pOwnerDb.Columns[columnIndex], value);
// Check that value won't exceed maximum cloumn allowed size
if (val.Length > m_ColumnDataSizes[columnIndex])
{
throw new Exception("Value exceeds maximum allowed value for column '" + m_pOwnerDb.Columns[columnIndex].ColumnName + "' !");
}
// TODO: String, string must be char(0) terminated and padded to column length
if (m_ColumnDataTypes[columnIndex] == LDB_DataType.String)
{
throw new Exception("TODO: String not implemented !");
}
// Update value in database file
m_pOwnerDb.WriteToFile(m_Pointer + m_ColumnDataStartOffsets[columnIndex], val, 0, val.Length);
// Update value in buffer
Array.Copy(val, 0, m_RowData, m_ColumnDataStartOffsets[columnIndex], val.Length);
}
}
/// <summary>
/// Appends new record to table.
/// </summary>
public void AppendRecord(object[] values)
{
if (!this.IsDatabaseOpen)
{
throw new Exception("Database isn't open, please open database first !");
}
if (m_pColumns.Count != values.Length)
{
throw new Exception("Each column must have corresponding value !");
}
bool unlock = true;
// Table is already locked, don't lock it
if (this.TableLocked)
{
unlock = false;
}
else
{
LockTable(15);
}
/* Fixed record structure:
* 1 byte - specified is row is used or free space
* u - used
* f - free space
* x bytes - columns data
* 2 bytes - CRLF
*/
int rowLength = 1 + 2;
for (int i = 0; i < m_pColumns.Count; i++)
{
rowLength += m_pColumns[i].ColumnSize;
}
int position = 1;
byte[] record = new byte[rowLength];
record[0] = (int)'u';
record[rowLength - 2] = (int)'\r';
record[rowLength - 1] = (int)'\n';
for (int i = 0; i < values.Length; i++)
{
byte[] columnData = LDB_Record.ConvertToInternalData(m_pColumns[i], values[i]);
// Check that column won't exceed maximum length.
if (columnData.Length > m_pColumns[i].ColumnSize)
{
throw new Exception("Column '" + m_pColumns[i] + "' exceeds maximum value length !");
}
Array.Copy(columnData, 0, record, position, columnData.Length);
position += columnData.Length;
}
// Find free row
byte[] freeRowsBuffer = new byte[4];
ReadFromFile(52, freeRowsBuffer, 0, freeRowsBuffer.Length);
int freeRows = ldb_Utils.ByteToInt(freeRowsBuffer, 0);
// There are plenty free rows, find first
if (freeRows > 100)
{
//--- Find free record ---------------------------------------------------//
long nextRowStartOffset = m_RowsStartOffset;
long rowOffset = 0;
byte[] rowData = new byte[m_RowLength];
while (true)
{
ReadFromFile(nextRowStartOffset, rowData, 0, m_RowLength);
// We want used row
if (rowData[0] == 'f')
{
rowOffset = nextRowStartOffset;
break;
}
nextRowStartOffset += m_RowLength;
}
//-------------------------------------------------------------------------//
// Write new record to file
WriteToFile(rowOffset, record, 0, record.Length);
// Update free rows count
WriteToFile(52, ldb_Utils.IntToByte(freeRows - 1), 0, 4);
}
// There are few empty rows, just append it
else
{
AppendToFile(record, 0, record.Length);
}
if (unlock)
{
UnlockTable();
}
}