boost - Custom hash in std::unordered map in C++ -

i want meet performance requirements in c++ project. have found using push_back std::vector has performance penalty. when use find elements of std::vector takes more time using unordered_map.

is ok if use emplace on unordered_map? can save/get cycle done faster?

g++ driver.cpp -std=c++11

the header file is

#ifndef custom_unor_map_hpp #define custom_unor_map_hpp   #include <boost/algorithm/string/predicate.hpp> #include <boost/functional/hash.hpp> #include <unordered_map>   namespace pe {      struct pe_hash     {          size_t operator()(const std::string& key) const         {              std::size_t seed = 0;             std::locale locale;              for(auto c : key)             {                 boost::hash_combine(seed, std::toupper(c, locale));             }              return seed;          }     };        struct pe_key_eq     {          bool operator()(const std::string& l, const std::string& r) const         {             return boost::iequals(l, r);         }     };      using pe_map = std::unordered_map<std::string, std::string, pe_hash, pe_key_eq>;  }  #endif 

the driver file (main.cpp)

#include "pemap.hpp" #include <iostream>   template <typename t>      inline const std::string& get_map_value(const t& container, const std::string& key)      {          if (container.count(key))         {              return container.find(key)->second;          }          static std::string empty;         return empty;      }  int main(int argc, char** argv) {       std::string key = "key";     std::string val = "value1";     std::string val2 = "value2";      pe::pe_map container;     container.emplace(std::move(key), std::move(val));     container.emplace(std::move(key), std::move(val2));      std::cout << get_map_value( container, "key") << std::endl;  } 

i want meet performance requirements in c++ project.

here steps should do:

• run profiler
• identify code , data manipulation takes time
• think better algorithm and/or data organization case (container type 1 of them)
• if performance enough, done, if not try optimize code, takes time

you not answer @ container in vanilla example. need optimize program, not example.