Re: [gobo-eiffel-develop] Crash in DS_HASH_TABLE

[Wolfgang J. <wj...@so...>]

Eric Bezault wrote:
> Wolfgang Jansen wrote:
>> some time ago I already asked a related question and you
>> gave an answer. But I may have misunderstood something.
>> The problem is as follows. I have a class like
>>
>>   class C
>>   inherit
>>     DS_EQUALITY_TESTER [KEY_TYPE]
>>       redefine test
>>     end
>>
>>   feature
>>
>>     table: DS_HASH_TABLE [ITEM_TYPE,KEY_TYPE]
>>
>>     make is
>>       do
>>         create table.make_with_equality_testers(1000, Void, Current)
>>       end
>>
>>     build(k: KEY_TYPE): ITEM_TYPE is
>>       do
>>         if table.has(k) then
>>           Result := table.item(k)
>>         else
>>           create Result.make(k)
>>           table.force(Result,k)
>>         end
>>       end
>>
>>     test(u,v: STRING) is
>>       do
>>         -- I would like to do this more intelligent,
>>         -- but this is a different problem
>>         Result := u = v
>>       end
>>
>>    -- other features
>>
>>   end
>>
>> This works very well for some time (hundreds of calls)
>> but then routine `search_position' enters an infinite loop:
>> Lines 590,591 of DS_SPARSE_CONTAINER are
>>   prev := i
>>   i := clashes_item(i)
>> and have the effect that `prev=1', `i=1', i.e. no further
>> progress happens. A particular observation:
>> `table' has currently 1028 elements.
>>
>> So, what has gone wrong and how can I fix the bug?
>
> Is the value of the hash_code of your keys changing while
> these keys are used in the hash table?
>
I don't know, the key type is ET_FEATURE.
So, you may answer this best yourself.

-- 
Wolfgang Jansen
University of Potsdam, Germany
mailto: wj...@so...