[fpc-pascal] IntList

[Michael Van Canneyt]

On Tue, 19 Oct 2010, Sven Barth wrote:

> Am 19.10.2010 19:54, schrieb Juha Manninen (gmail):
>> On Tuesday 19 October 2010 19:10:39 Luiz Americo Pereira Camara wrote:
>>> Yes it's ready in fpc 240:
>>> 
>>> uses
>>>    Fgl;
>>> 
>>> type
>>>    TIntegerList = specialize TFPGList<Integer>;
>> 
>> Well, yes. It is almost as good as a dedicated class. It has a Sort method 
>> but
>> you must feed the compare function for it.
>> It does not have a Find method for a binary search in a sorted list.
>> Indexof does a linear search.
>> 
>> Anyway, it could be used as a base class in Lazarus. I don't know what is 
>> the
>> Lazarus team's policy for using generics in Lazarus code-base.
>> 
>> In FPC 2.4.0 I had problems with memory consumption of generics containers.
>> A<Integer, Integer>  map hogged gigabytes of memory while my data took only
>> kilobytes (less than 1 MB for sure), on a 64 bit Linux.
>> Now I have the latest FPC trunk 2.5.1 and the problems are gone. I added
>> 100000 integers to both a List and to a Map and didn't even notice the 
>> memory
>> increase in resource monitor.
>>
>>    TIntegerList = specialize TFPGList<Integer>;
>>    TIntegerMap = specialize TFPGMap<Integer, Integer>;
>> 
>> TFPGMap's problem still is that it is not a hash map and is butt-slow with
>> lots of data. A hash map is a superior container type, it really should be
>> changed.
>> Besides, people expect to get a hash map when they see "map" in the class
>> name. Now they get a list which is deceivingly named as "map".
>
> As you seem to have experience with efficient data structures, what about 
> creating such a generic hash map? :)
>
> (but don't use 2.4.2rc1 and current/unpatched 2.4.3 as a test base as those 
> don't have the fixes from trunk to make "specialize" working again)

Currently, the FPC team is looking at an implementation of Vlado Boza 
<usama at ksp.sk> for a standard template library for inclusion in FPC.

The code is on

http://code.google.com/p/stlpascal

Please have a look and comment on it.

I'm not a generics expert and am not in the position to judge whether this library is good or not.

Michael.