private ErrType add_remove(SpreadsheetCell toAlter, ExpTree mainTree, bool removing)
{
/*Adding to and removing from the reference table occurs in this function*/
ErrType Error = ErrType.None;
if (toAlter.VarList != null && toAlter.VarList.Count > 0)
{
string referencedBy = CellToString(toAlter);
if (removing)
{
foreach (string referencedCell in toAlter.VarList) // Removes all variables from the old tree
{
if (refTable.ContainsKey(referencedCell))
{
if (refTable[referencedCell].Contains(referencedBy))
refTable[referencedCell].Remove(referencedBy); // Removes the current cell from any other cells referencing hash
if (refTable[referencedCell].Count < 1) // If an entry in the table has no cells referencing it, then it is removed
refTable.Remove(referencedCell);
}
}
toAlter.VarList.Clear(); // Empty that variable list (will be rebuild below)
}
else // Adding value to the reference this
{
foreach (string s in toAlter.VarList) // Updates the reference table with all of the referenced cells (variables in the expTree's context)
{
double CellValue = 0.0;
SpreadsheetCell next = StringToCell(s);
if (next != null)
{
if (s == CellToString(toAlter)) // SELF-REFERENCING
{
Error = ErrType.SelfRef;
CheckErr(toAlter, Error, CellToString(toAlter));
UpdateErrorReferecedBy(toAlter, ErrType.SelfRef, CellToString(toAlter)); // Updates all cells referencing this cell that there is a value
return ErrType.SelfRef;
}
else if (next.Value.Contains("REF")) // Won't check for already occuring errors (in referenced cell)
{
if (next.Value.Contains("=<BAD_REF")) // If this cell REFERENCES a cell that contains a bad_ref error
{
CheckErr(toAlter, ErrType.BadRef, s);
UpdateErrorReferecedBy(toAlter, ErrType.BadRef, s);
Error = ErrType.BadRef;
}
else if (next.Value.Contains("=<SELF_REF")) // If this cell REFERENCES a cell that contains a self_ref error
{
CheckErr(toAlter, ErrType.SelfRef, s);
UpdateErrorReferecedBy(toAlter, ErrType.SelfRef, CellToString(toAlter));
Error = ErrType.SelfRef;
}
else if (next.Value.Contains("=<CIRC_REF"))
{
CheckErr(toAlter, ErrType.CircRef, s);
UpdateErrorReferecedBy(toAlter, ErrType.CircRef, CellToString(toAlter));
Error = ErrType.CircRef;
}
}
if (next.Text != "")
{
Double.TryParse(next.Value, out CellValue); // Gets the cell's value
mainTree.SetVar(s, CellValue); // Sets the variable in the expression tree's dictionary (0 if not yet set)
}
if (refTable.ContainsKey(s)) // If The variable already has references, just add to its hash
refTable[s].Add(referencedBy);
else // Otherwise create the new variable key with a new list containing the cell that references it
refTable.Add(s, new HashSet<string>() { referencedBy });
}
else // If Cell parsing return null (cell not recovered), the there is a bad reference
{
Error = ErrType.BadRef;
CheckErr(toAlter, Error, CellToString(toAlter));
UpdateErrorReferecedBy(toAlter, ErrType.BadRef, CellToString(toAlter));
return ErrType.BadRef;
}
}
if (Error == ErrType.CircRef)
return Error;
if (Error != ErrType.SelfRef && CheckCircularRef(toAlter, CellToString(toAlter))) // Checks for circular references here ***
{
Error = ErrType.CircRef;
CheckErr(toAlter, Error, CellToString(toAlter));
UpdateErrorReferecedBy(toAlter, ErrType.CircRef, CellToString(toAlter));
}
}
}
return Error;
}
