[fpc-pascal] IntList

[Michael Van Canneyt]

Hi,

I asked around.

We'd like to propose the following:
- We import the code in the FPC subversion repository, in a package.
- You get read/write access to the package, so you can maintain it.
Subject to 2 conditions:

- You use the FPC license.
- Please remove all _ characters at the start of identifiers.
   This goes against our coding rules.
   (we try to avoid _ as much as possible)

If you can agree with this, I'll import the code in the FPC repository.

Michael.


On Wed, 3 Nov 2010, Vlado Boza wrote:

> On 10/19/2010 08:28 PM, Michael Van Canneyt wrote:
>> 
>> 
>> 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.
>> 
>
> Hash_map implementation shouldn't be a big problem. But I also think, that 
> other structures can be usefull as well (for example in map done by red-black 
> tree you can find greatest key which less than X in a good time, ...).
>
> A is there any decision if it is worth to put it in FPC and where to put it?
>
> Vlad.
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