Session-aware-allocation supporting with hyperscan

[hurricane1026]

hi, everybody I am using hyperscan do some serious heavy-load query works in c++. For the best performance, our project hire session-aware-memory-allocation technology, just like Google's Arena. pls see Protobuf's Arena Document. I noticed that hyperscan library support use customized allocation function. from hs_set_allocator but this API was not designed for our scenairo, we cannot passing a c++ object's member funtion as c-style-function-ptr, so I need an another parameter just like a void*, then I can pass the Arena object ptr into the stateless global allocation function. hs_error_t hs_set_allocator(void*(size_t, void*) alloc_func, void* ctx, void(void*, void*) free_func, void* ctx) I hope u guys like this idea, and implement it, it can really boost hyperscan in some heavy-load quering services.

[mustafakemalgilor]

I think you can use the following workaround to overcome the limitation:

void * instance_to_assign  = nullptr;

void * my_alloc_impl(void * ptr, std::size_t sz){
    /* your instance-aware allocator call here */
}

void* my_alloc(std::size_t sz){
    thread_local void * instance = instance_to_assign; 
    return my_alloc_impl(instance, sz);
} 

struct my_allocator{};

int main(void) {
  auto my_alloc_instance = new my_allocator();
  instance_to_assign=  (void*)my_alloc_instance;
  // Call once to init the thread-local variable in the function
  my_alloc(0);
  hs_set_allocator(&my_alloc);
}

[hurricane1026]

thread-local really works for this case, and I have to use multiple allocator instances within single thread. I wonder why hyperscan do not support more flexible hs_set_allocator.

[hongyang7]

Sorry we don't have plans for it currently.