[fpc-pascal] sorting and merging array of records

[waldo kitty]

On 1/10/2012 16:41, Sven Barth wrote:
> On 10.01.2012 22:02, waldo kitty wrote:
>> TList? hummm... better? smaller? faster? easier to use? small memory
>> footprint? i'm game to try things as long as it works in the end ;)
>
> TList is basically an array wrapped in a class (though I would suggest TFPList
> as that is faster than TList (TList is based on TFPList)). Both can be found in
> unit Classes.
>
> The following you need to know: T(FP)List works on pointers, thus you need to
> 1. declare a pointer type to your record type (e.g. Pthree_line_data =
> ^three_line_data)
> 2. allocate a Pthree_line_data variable if you want to add a new entry to the list

i tried this but could only get so far and then not further so i backed up and 
punted the ball... now i'm trying this with a sortedcollection and while i can 
apparently insert items, i haven't figured out how to access them and print 
their contents... unless their contents are garbage like the following prints out...


program satsort;

uses {$IFDEF DEBUG}heaptrc,{$ENDIF}objects,math,crt,dos;

type
   vector     = array [1..4] of double;
   cat_nbr    = string[5];
   sat_name   = string[25];
   line_data  = string[69];
   two_line   = array [1..2] of line_data;
   PTLERec    = ^TTLERec;
   TTLERec    = record
                  satname : sat_name;
                  satdata : two_line;
                  catnbr  : cat_nbr;
                  epoch   : double;
                end;
   TTLERecObj = object(TObject)
                  TLEData : PTLERec;
                  constructor Init;
                  destructor Done; virtual;
                end;
   constructor TTLERecObj.Init;
   begin
     new(TLEData);
   end;
   destructor TTLERecObj.Done;
   begin
     dispose(TLEData);
   end;

type
   PTLECollection = ^TTLECollection;
   TTLECollection = object(TSortedCollection)
     TLERec : TTLERecObj;
     function Compare(Key1, Key2 : Pointer): longint; virtual;
   end;

function TTLECollection.Compare(key1, key2: pointer): longint;
begin
   if PTLERec(key1)^.catnbr = PTLERec(key2)^.catnbr then
     compare := 0
   else if PTLERec(key1)^.catnbr < PTLERec(key2)^.catnbr then
     compare := -1
   else
     compare := 1;
end;

const
   data_type : byte = 3;
//  max_sats = {$IFDEF FPC}65536{$ELSE}250{$ENDIF};

var
   data_drive,data_dir,
   work_drive,work_dir  : string;
   UTC_offset           : double;
   DST                  : boolean;
   fsat,fobs            : text;
   obs_name             : string[25];
   piss                 : vector;
   gigo                 : char;
   my_sats              : word;
   aTLERec              : PTLERec;
   aTLECollection       : PTLECollection;

[...]

Function Input_Satellite_List(var aInputFile: TextFile) : word;

var
   data    : PTLERec;
   sat_cnt : word;
   i,x     : longint;

begin
   sat_cnt := 0;
   while not EOF(aInputFile) do
     begin
       new(data);
       Readln(aInputFile,data^.satname);
       Readln(aInputFile,data^.satdata[1]);
       Readln(aInputFile,data^.satdata[2]);
       data^.catnbr := Copy(data^.satdata[1],3,5);
       data^.epoch  := Real_Value(data^.satdata[1],19,14);
       inc(sat_cnt);
       aTLECollection^.insert(data);
       dispose(data);
       {$IFDEF DEBUG}
       writeln(PTLERec(aTLECollection)^.satname);
       writeln(PTLERec(aTLECollection)^.satdata[1]);
       writeln(PTLERec(aTLECollection)^.satdata[2]);
       writeln(PTLERec(aTLECollection)^.catnbr);
       writeln(PTLERec(aTLECollection)^.epoch);
       {$ENDIF}
     end; {while not EOF}
   Input_Satellite_List := sat_cnt;
end; {Procedure Input Satellite List}