Boost.Multiindex
Đây là một Boost example
Trong ví dụ trên một chỉ số lệnh được sử dụng nhưng bạn có thể sử dụng cũng là một chỉ số băm:
#include <boost/multi_index_container.hpp>
#include <boost/multi_index/member.hpp>
#include <boost/multi_index/ordered_index.hpp>
#include <boost/multi_index/hashed_index.hpp>
#include <string>
#include <iostream>
struct employee
{
int id_;
std::string name_;
std::string address_;
employee(int id,std::string name,std::string address):id_(id),name_(name),address_(address) {}
};
struct id{};
struct name{};
struct address{};
struct id_hash{};
struct name_hash{};
typedef boost::multi_index_container<
employee,
boost::multi_index::indexed_by<
boost::multi_index::ordered_unique<boost::multi_index::tag<id>, BOOST_MULTI_INDEX_MEMBER(employee,int,id_)>,
boost::multi_index::ordered_unique<boost::multi_index::tag<name>,BOOST_MULTI_INDEX_MEMBER(employee,std::string,name_)>,
boost::multi_index::ordered_unique<boost::multi_index::tag<address>, BOOST_MULTI_INDEX_MEMBER(employee,std::string,address_)>,
boost::multi_index::hashed_unique<boost::multi_index::tag<id_hash>, BOOST_MULTI_INDEX_MEMBER(employee,int,id_)>,
boost::multi_index::hashed_unique<boost::multi_index::tag<name_hash>, BOOST_MULTI_INDEX_MEMBER(employee,std::string,name_)>
>
> employee_set;
typedef boost::multi_index::index<employee_set,id>::type employee_set_ordered_by_id_index_t;
typedef boost::multi_index::index<employee_set,name>::type employee_set_ordered_by_name_index_t;
typedef boost::multi_index::index<employee_set,name_hash>::type employee_set_hashed_by_name_index_t;
typedef boost::multi_index::index<employee_set,id>::type::const_iterator employee_set_ordered_by_id_iterator_t;
typedef boost::multi_index::index<employee_set,name>::type::const_iterator employee_set_ordered_by_name_iterator_t;
typedef boost::multi_index::index<employee_set,id_hash>::type::const_iterator employee_set_hashed_by_id_iterator_t;
typedef boost::multi_index::index<employee_set,name_hash>::type::const_iterator employee_set_hashed_by_name_iterator_t;
int main()
{
employee_set employee_set_;
employee_set_.insert(employee(1, "Employer1", "Address1"));
employee_set_.insert(employee(2, "Employer2", "Address2"));
employee_set_.insert(employee(3, "Employer3", "Address3"));
employee_set_.insert(employee(4, "Employer4", "Address4"));
// search by id using an ordered index
{
const employee_set_ordered_by_id_index_t& index_id = boost::multi_index::get<id>(employee_set_);
employee_set_ordered_by_id_iterator_t id_itr = index_id.find(2);
if (id_itr != index_id.end()) {
const employee& tmp = *id_itr;
std::cout << tmp.id_ << ", " << tmp.name_ << ", " << tmp .address_ << std::endl;
} else {
std::cout << "No records have been found\n";
}
}
// search by non existing id using an ordered index
{
const employee_set_ordered_by_id_index_t& index_id = boost::multi_index::get<id>(employee_set_);
employee_set_ordered_by_id_iterator_t id_itr = index_id.find(2234);
if (id_itr != index_id.end()) {
const employee& tmp = *id_itr;
std::cout << tmp.id_ << ", " << tmp.name_ << ", " << tmp .address_ << std::endl;
} else {
std::cout << "No records have been found\n";
}
}
// search by name using an ordered index
{
const employee_set_ordered_by_name_index_t& index_name = boost::multi_index::get<name>(employee_set_);
employee_set_ordered_by_name_iterator_t name_itr = index_name.find("Employer3");
if (name_itr != index_name.end()) {
const employee& tmp = *name_itr;
std::cout << tmp.id_ << ", " << tmp.name_ << ", " << tmp .address_ << std::endl;
} else {
std::cout << "No records have been found\n";
}
}
// search by name using an hashed index
{
employee_set_hashed_by_name_index_t& index_name = boost::multi_index::get<name_hash>(employee_set_);
employee_set_hashed_by_name_iterator_t name_itr = index_name.find("Employer4");
if (name_itr != index_name.end()) {
const employee& tmp = *name_itr;
std::cout << tmp.id_ << ", " << tmp.name_ << ", " << tmp .address_ << std::endl;
} else {
std::cout << "No records have been found\n";
}
}
// search by name using an hashed index but the name does not exists in the container
{
employee_set_hashed_by_name_index_t& index_name = boost::multi_index::get<name_hash>(employee_set_);
employee_set_hashed_by_name_iterator_t name_itr = index_name.find("Employer46545");
if (name_itr != index_name.end()) {
const employee& tmp = *name_itr;
std::cout << tmp.id_ << ", " << tmp.name_ << ", " << tmp .address_ << std::endl;
} else {
std::cout << "No records have been found\n";
}
}
return 0;
}
Boost đa Index container xử lý đó rất tốt http://www.boost.org/doc/libs/ 1_41_0/libs/multi_index/doc/index.html – adrianm
Bạn chỉ có thể đặt một tiêu chí đặt hàng cho một bản đồ nhất định. Với STL đơn giản, bạn có thể sử dụng hai bản đồ, một bản đặt hàng của Name và cái kia bởi Employee_Id hoặc người khác sử dụng container Boost Multi Index. –