Re: [boost] [Block Pointer] Update

On 03/09/2016 11:28 PM, Phil Bouchard wrote:

Hi,

- So I've restructured all the code in the correct namespaces boost::smart_ptr & boost::smart_ptr::detail: https://github.com/philippeb8/block_ptr/tree/master/include/boost/smart_ptr

- I am now using another smart pointer to refer to proxies because it is safer but the code is 15% slower than without it (now ~= shared_ptr<>):

make: auto_ptr: 26211292 ns shared_ptr: 27291607 ns block_ptr: 61097868 ns

new: auto_ptr: 23240569 ns shared_ptr: 48016207 ns block_ptr: 55554121 ns

Note that it is possible & easy to use the fast_pool_allocator to allocate objects just by using the following line in benchmark.cpp: worker_new< boost::block_ptr<int>, fastblock<int> >(); Or: https://github.com/philippeb8/block_ptr/blob/master/example/benchmark.cpp#L9... And this way block_ptr<> will be 5% faster than shared_ptr<>: make: auto_ptr: 25673501 ns shared_ptr: 26853061 ns block_ptr: 61874962 ns new: auto_ptr: 22326728 ns shared_ptr: 47143526 ns block_ptr: 45007803 ns This is an unfair comparison but my point is using this fast allocator can be done easily.

- Because of the removal of the proxy optimization there is a new caveat; if you assign an rvalue (temporary pointer on the stack) to a pointer on the heap (opposite of normal heap object assigned to stack pointer) then there the behavior will be undefined. I am looking to fix it or throw an exception but for now it's better not to use rvalues when assigning to pointer living on the heap as such: https://github.com/philippeb8/block_ptr/blob/master/example/t100_test1.cpp#L...

I fixed the problem and now the correct way to use the pointer is by passing around a proxy explicitly: [...] block_ptr t100 = new block("I eat ([a-z]+) then drink ([a-z]+)"); t100->sub_[0].second = block_ptr(t100.proxy(), new block("beef|chicken")); t100->sub_[1].second = block_ptr(t100.proxy(), new block("vodka|water")); Or: https://github.com/philippeb8/block_ptr/blob/master/example/t100_test1.cpp#L... I will fix make_block<>() to follow this syntax but this is how things should be done. Another useful example is by defining the internals of a container: struct list { public: list() {} void clear() { root.reset(); } void insert() { if(root.get() == 0) { root = new block<node>(); } else { root->next = block_ptr<node>(root.proxy(), new block<node>()); //<- Correct way root->next->prior = root; root = root->next; } } ~list() { } private: block_ptr<node> root; }; Or: https://github.com/philippeb8/block_ptr/blob/master/example/block_ptr_test2.... The explicit proxy states where a set of allocations should be defined as unique. That set can be merged with another set. Regards, -Phil