Earlier versions of the library included an Xbase specific functin called "Real Delete"

The analysis is as follows:

Updates to xbdbf.h and xbdbf.cpp

#ifdef XB_REAL_DELETE
  ...
#endif

Functions included:

  RealDeleteOn()           Turns on RealDelete
  RealDeleteOff()          Turns off RealDelete
  GetRealDelete()          Returns the status of RealDelete

Narrative:

This should be done before creating a database with xbDbf::CreateDatabase() and 
thereafter before opening a database with xbDbfCreateDatabase()


You can not turn on real deletes once a database has been created and records added


In the Table header
bytes 12-15 - FirstFreeRec;
bytes 16-19 - RealNumRecs


Updates to the following methods:
WriteHeader()
ReadHeader()

The first four bytes of the deleted record is the record number to the next
deleted record in the chain

Append Record will pull next record from the chain and attempt to use that
field, otherwise it will append a new record

GetFirstRecord will skip over deleted records looking for the first record
which is not deleted

GetLastRecord will skip backwards to the next previous undeleted record

GetPrevRecord skips backwards to the the next previous undeleted record

DeleteRecord 
  -Deletes the memo data 
  - Adds the record to the front of the free chain
  
UndeleteRecord 
 - Always returns XB_INVALID_RECORD
 
PackDatafiles
 - Deleted Records are skipped
 
NoOfRecords
 - Returns no of records not deleted
 
PhysicalNoOfRecords()
 - Return NoOfRecs - actual number of records in the file
 


Conclusions:

From a campatibility standpoint:

  This setup will only work on the earlier version of the Xbase file format as this would 
  be library specific code.

  Also, once past Dbase V3, the bytes used in the header file are used by Dbase 4,5,7


Decision:

  In an effort to make the library as portable as possible moving forward, a decision was made to
  leave this code out of the basic library.  To add this code in the future, a new class can be created
  using the xbDbf class as a base class, and override the methods mentioned above.