/// <summary>
/// Opens specified data file.
/// </summary>
/// <param name="fileName">File name.</param>
/// <param name="waitTime">If data base file is exclusively locked, then how many seconds to wait file to unlock before raising a error.</param>
public void Open(string fileName, int waitTime)
{
DateTime lockExpireTime = DateTime.Now.AddSeconds(waitTime);
while (true)
{
try{
m_pDbFile = File.Open(fileName, FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite);
break;
}
catch (IOException x) {
if (!File.Exists(fileName))
{
throw new Exception("Specified database file '" + fileName + "' does not exists !");
}
// Make this because to get rid of "The variable 'x' is declared but never used"
string dummy = x.Message;
System.Threading.Thread.Sleep(15);
// Lock wait time timed out
if (DateTime.Now > lockExpireTime)
{
throw new Exception("Database file is locked and lock wait time expired !");
}
}
}
/* Table structure:
* 50 bytes - version
* 2 bytes - CRLF
* 4 bytes - Free rows count
* 2 bytes - CRLF
* 100 x 500 bytes - 100 columns info store
* 2 bytes - CRLF
* ... data pages
*/
m_DbFileName = fileName;
// TODO: check if LDB file
// Read version line (50 bytes + CRLF)
byte[] version = new byte[52];
ReadFromFile(0, version, 0, version.Length);
// Read free rows count
byte[] freeRows = new byte[6];
ReadFromFile(0, freeRows, 0, freeRows.Length);
long currentColumnOffset = 58;
// Read 100 column lines (500 + CRLF bytes each)
for (int i = 0; i < 100; i++)
{
byte[] columnInfo = new byte[102];
if (ReadFromFile(currentColumnOffset, columnInfo, 0, columnInfo.Length) != columnInfo.Length)
{
throw new Exception("Invalid columns data area length !");
}
if (columnInfo[0] != '\0')
{
m_pColumns.Parse(columnInfo);
}
currentColumnOffset += 102;
}
// Header terminator \0
m_pDbFile.Position++;
// No we have rows start offset
m_RowsStartOffset = m_pDbFile.Position;
// Store file length and position
m_FileLength = m_pDbFile.Length;
m_FilePosition = m_pDbFile.Position;
// Calculate row length
m_RowLength = 1 + 2;
for (int i = 0; i < m_pColumns.Count; i++)
{
m_RowLength += m_pColumns[i].ColumnSize;
}
m_RowDataBuffer = new byte[m_RowLength];
}
/// <summary>
/// Opens specified data file.
/// </summary>
/// <param name="fileName">File name.</param>
/// <param name="waitTime">If data base file is exclusively locked, then how many seconds to wait file to unlock before raising a error.</param>
public void Open(string fileName, int waitTime)
{
DateTime lockExpireTime = DateTime.Now.AddSeconds(waitTime);
while (true)
{
try{
m_pDbFile = File.Open(fileName, FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite);
break;
}
catch (IOException x) {
// Make this because to get rid of "The variable 'x' is declared but never used"
string dummy = x.Message;
System.Threading.Thread.Sleep(15);
// Lock wait time timed out
if (DateTime.Now > lockExpireTime)
{
throw new Exception("Database file is locked and lock wait time expired !");
}
}
}
/* Table structure:
* 50 bytes - version
* 2 bytes - CRLF
* 8 bytes - free datapages count
* 2 bytes - CRLF
* 4 bytes - datapage data area size
* 2 bytes - CRLF
* 100 x 500 bytes - 100 columns info store
* 2 bytes - CRLF
* ... data pages
*/
m_DbFileName = fileName;
StreamLineReader r = new StreamLineReader(m_pDbFile);
// TODO: check if LDB file
// Read version line (50 bytes + CRLF)
byte[] version = r.ReadLine();
// Skip free data pages count
byte[] freeDataPagesCount = new byte[10];
m_pDbFile.Read(freeDataPagesCount, 0, freeDataPagesCount.Length);
// 4 bytes datapage data area size + CRLF
byte[] dataPageDataAreaSize = new byte[6];
m_pDbFile.Read(dataPageDataAreaSize, 0, dataPageDataAreaSize.Length);
m_DataPageDataAreaSize = ldb_Utils.ByteToInt(dataPageDataAreaSize, 0);
// Read 100 column lines (500 + CRLF bytes each)
for (int i = 0; i < 100; i++)
{
byte[] columnInfo = r.ReadLine();
if (columnInfo == null)
{
throw new Exception("Invalid columns data area length !");
}
if (columnInfo[0] != '\0')
{
m_pColumns.Parse(columnInfo);
}
}
// Header terminator \0
m_pDbFile.Position++;
// No we have rows start offset
m_DatapagesStartOffset = m_pDbFile.Position;
// Store file length and position
m_FileLength = m_pDbFile.Length;
m_FilePosition = m_pDbFile.Position;
}
