Re: [boost] [ boost ] [ Trie ]

Hello,

As a temporary workaround operator*() could return pair by value.

Operator*() works fine and is already returning that, the problem is with operator->. Also, I don't know what do you mean when you tell me to return it by value. Thank you, Cosmin On 22 February 2015 at 18:58, Antony Polukhin wrote:

2015-02-22 16:23 GMT+03:00 Cosmin Boaca :

...

Hello,

I have performed the modifications required in order to use std::reverse_iterator instead of trie_iterator. [0]. Also, I have optimized the get_key function [1]. The overall diff can be found here [2]. Please give me some feedback about the code when you have time.

Good, added a few minor comments.

...

Also, it seems to be a problem with trie_iterator::operator->. It doesn't work and I think it may cause memory corruption. I think the problem is that it returns &(operator *()) which is a value allocated on stack that gets destroyed when it goes out of scope. However, I don't know how it should be implemented. Please tell me what do you think about this operator. As a workaround, instead of using this operator I have used operator * and the code passes the tests.

As a temporary workaround operator*() could return pair by value.

Ideal hard to implement solution would be to use Boost intrusive's slist or develop own slist and use slist in node and instead of std::vector:

// pseudocode template <class Key> class slist: public slist_base_hook<> { slist* parent_; Key key_;

slist_iterator begin() { return this; } slist_iterator end() { return 0; } // ...

std::vector<Key> to_vector() { std::vector<Key> key_path; key_path.reserve(this->size());

std::copy(this->begin(), this->end(), std::back_inserter(key_path));

return key_path; } };

template class node: public pair {};

class trie_iterator { node* vnode;

reference operator*() { return static_cast>(*vnode); } }

But this can wait... Simple task: trie_iterator accepts 4 template parameters, while Key and Value types seem enough. Try to remove two template parameters, take care of almost identical iterator_type and iter_type typedefs,

-- Best regards, Antony Polukhin

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