Re: phone number database

[mheaney@on2.com (Matthew Heaney)]

Stephen Leake <Stephen.A.Leake@nasa.gov> wrote in message news:<uk7fliqhx.fsf_-_@nasa.gov>...
> "Anders Wirzenius" <anders.wirzenius@pp.qnet.fi> writes:
> 
> > I HAVE:
> > 1.
> > Six phone numbers: 1795, 2006, 2007, 2012, 2013, 2014.
> > 2.
> > A log (text file) from the company's phone system with data like:
> > From_Phone_Nr, To_Phone_Nr, Answering_Time, Duration... 
> > 
> > I WANT TO:
> > 3.
> > Pick only those log data where the To_Phone_Nr is one of the six numbers.
> > 4.
> > Set up some statistics about those phone calls.
> > 5.
> > Be able to add or remove phone numbers from the list (six becomes
> > seven some sunny winterday). 
> > 
> > I WISH I HAD:
> > type Help_Desk is (1795, 2006, 2007, 2012, 2013, 2014); -- with the
> > dynamics described under point 5. 
> 
> > What is a proper way to implement "To_Phone_Nr in Help_Desk" ? 
> 
> Use a SAL binary tree
> (http://users.erols.com/leakstan/Stephe/Ada/Sal_Packages/index.htm) to
> store the help desk phone numbers; then do
[ex snipped]

If you just want a membership test, you can always use a set:

package Phone_Number_Type is
   new Charles.Sets.Sorted.Unbounded (Phone_Number_Type);

Set : Phone_Number_Types.Container_Type;

if Find (Set, Phone_Number) /= Back (Set) then ...

If you need to store some data with each number, you can could still
use a set:

type Info_Type is
   record
      Phone_Number : Phone_Number_Type;
      ...
   end record;

function "<" (L, R : Info_Type) return Boolean is
begin
   return L.Phone_Number < R.Phone_Number;
end;

package Phone_Number_Info is
   new Charles.Sets.Sorted.Unbounded (Info_Type, "<");

Set : Phone_Number_Info.Container_Type;

procedure Op (X : Phone_Number_Type) is
   I : constant Iterator_Type := Find (Set, X);
begin
   if I /= Back (Set) then
      declare
         Info : Info_Type renames To_Access (I).all;
      begin
         --manipulate Info as necessary
      end;
   end if;
end Op;

You could also use a map, which stores the phone number separately
from the info:

package Phone_Number_Info is
   new Charles.Maps.Sorted.Unbounded
     (Phone_Number_Type, 
      Info_Type); --extra info only, sans phone number

Map : Phone_Number_Info.Container_Type;

procedure Op (X : Phone_Number_Type) is
   I : constant Iterator_Type := Find (Map, X);
begin
   if I /= Back (Map) then
     declare
        Info : Info_Type renames To_Access (I).all;
     begin
        --manipulate Info as necessary
     end;
   end if;
end Op;

To add another phone number, just insert it into the set or map.  For
example:

procedure Add 
  (X : Phone_Number_Type;
   Y : Info_Type) is

   I       : Iterator_Type;
   Success : Boolean;
begin
   Insert (Map, X, Y, I, Success);

   if not Success then
      --X already in map
   end if;
end Add;

You could also use the hashed versions, and use the phone number
itself as the value of the hash function for the phone number key. 
Then your lookups would only have O(1) average time complexity.

The hashed associative containers are nice because you can preallocate
the actual hash table:

Map : Hashed_Map_Subtype;

Resize (Map, Size => 6);

That guarantees there's no hash table allocation until the load factor
exceeds 1.

http://home.earthlink.net/~matthewjheaney/charles/

Drop me a line if you have any questions about Charles.

Matt