usama at ksp.sk
Wed Nov 3 13:23:39 CET 2010
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:
>>>> 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
>>> 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
>>> 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
>>> Besides, people expect to get a hash map when they see "map" in the
>>> 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
> 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
> 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.
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
A is there any decision if it is worth to put it in FPC and where to put it?
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