// Grid File  Interface April 10, 1995

//*********************** GridFile ******************************
#include <minirel.h>

class GridFile: public IndexFile {
friend class GridFileScan;

public:

GridFile::GridFile (Status &status, const char * filename,
          (const void * KeyTypes, const int max_string_length = 32, 
           const int num_dimensions = 2)
    //Status returns the status of this operation.
    //filename is name of file.
    //num_dimensions is number of index dimensions AND types in KeyTypes
    //KeyTypes is array of AttrType where each item is the type of the
    // corresponding dimension (numbered from 0) and then the
    // array is cast to type (void *) .
    // If GridFile index already exists, it is opened else
      //      it is created.
    // Dimensions and key types are stored in private class
    // variables for subsequent use by all GridFile procedures.


GridFile::GridFile (Status &status, char * filename)
     //If GridFile index exists, opens it else error. 
    //Status returns the status of this operation.


GridFile::~GridFile ()
      //destructor closes index

Status GridFile:insert_record(const void * KeyArray, const RID rid)
   // KeyArray is actually an array of pointers to voids the whole thing
   // cast to a void pointer. These are 
   // the keys for the respective dimensions being used. The array
   // must have an entry for each dimension 0 to 
   // num_dimensions - 1. No dimension key value should be unspecified
   // in insert_record.


Status GridFile:delete_record(const void * KeyArray, const RID rid)
   // KeyArray is actually an array of pointers to voids the whole thing
   // cast to a void pointer. These are 
   // the keys for the respective dimensions being used. The array
   // must have an entry for each dimension 0 to 
   // num_dimensions - 1. No dimension key value should be unspecified
   // in delete_record.

IndexFileScan * GridFile::new_scan (const void * LowKeys, 
                                    const void * HighKeys)
}
//***************************** Scans ****************************

GridFile_scan: public IndexFileScan
{public:

Status GridFile_scan:: get_next (RID & record_id)
    // Scan returns next record qualifies under ongoing scan if
    //        there is one.

Status GridFile_scan::delete_current_record()
    // Scan deletes current record

private:

Status GridFile_scan::GridFile_scan(GridFile * fileptr)
   //Full scan on given gridfile.


Status GridFile_scan::GridFile_scan(GridFile * fileptr,
         const void *KeyArray)
   //Create a case of an exact scan on given gridfile.
   //If a key is not being specified here then its pointer must
   // be set to null in the KeyArray. Looks for exact match on
   // keys that are specified. Key's dimension and type must 
   // match as in insert_record and delete_record.
   
Status GridFile_scan::GridFile_scan(GridFile * fileptr,
      const void *LowKeys, const void *HighKeys)
   //Create a case of min/max scan on given gridfile.
   //If a key is not being specified here then its pointer must
   // be set to null in the KeyArray. 
   // Key's dimension and type must 
   // match as in insert_record and delete_record.
   
}