libs/multi_index/example/complex_structs.cpp
/* Boost.MultiIndex example: complex searches and foreign keys.
*
* Copyright 2003-2008 Joaquin M Lopez Munoz.
* Distributed under the Boost Software License, Version 1.0.
* (See accompanying file LICENSE_1_0.txt or copy at
* http://www.boost.org/LICENSE_1_0.txt)
*
* See http://www.boost.org/libs/multi_index for library home page.
*/
#if !defined(NDEBUG)
#define BOOST_MULTI_INDEX_ENABLE_INVARIANT_CHECKING
#define BOOST_MULTI_INDEX_ENABLE_SAFE_MODE
#endif
#include <boost/multi_index_container.hpp>
#include <boost/multi_index/member.hpp>
#include <boost/multi_index/ordered_index.hpp>
#include <boost/tuple/tuple.hpp>
#include <iostream>
#include <string>
using boost::multi_index_container;
using namespace boost::multi_index;
/* This small utility that cascades two key extractors will be
* used througout the example.
*/
template<class KeyExtractor1,class KeyExtractor2>
struct key_from_key
{
public:
typedef typename KeyExtractor1::result_type result_type;
key_from_key(
const KeyExtractor1& key1_=KeyExtractor1(),
const KeyExtractor2& key2_=KeyExtractor2()):
key1(key1_),key2(key2_)
{}
template<typename Arg>
result_type operator()(Arg& arg)const
{
return key1(key2(arg));
}
private:
KeyExtractor1 key1;
KeyExtractor2 key2;
};
/* tags for accessing several indices defined below */
struct model{};
struct manufacturer{};
struct price{};
/* a manufacturer struct just holds the name of the manufacturer */
struct car_manufacturer
{
std::string name;
car_manufacturer(const std::string& name_):name(name_){}
};
/* car_model holds the model of car, its price and a pointer to the
* manufacturer. The pointer thing eliminates duplication of the same
* data among cars of the same manufacturer.
*/
struct car_model
{
std::string model;
const car_manufacturer* manufacturer;
int price;
car_model(
const std::string& model_,const car_manufacturer* manufacturer_,int price_):
model(model_),manufacturer(manufacturer_),price(price_)
{}
friend std::ostream& operator<<(std::ostream& os,const car_model& c)
{
os<<c.manufacturer->name<<" "<<c.model<<" $"<<c.price<<std::endl;
return os;
}
};
/* see Compiler specifics: Use of member_offset for info on
* BOOST_MULTI_INDEX_MEMBER
*/
/* Car manufacturers are stored in a multi_index_container with one single
* index on the name member. This is functionally equivalent to an std::set,
* though in this latter case we woud have to define a non-default comparison
* predicate (with multi_index_container, member<> does the work for us.)
*/
typedef multi_index_container<
car_manufacturer,
indexed_by<
ordered_unique<
BOOST_MULTI_INDEX_MEMBER(car_manufacturer,std::string,name)
>
>
> car_manufacturer_table;
/* Define a multi_index_container of car_models with following indices:
* - a unique index sorted by car_model::model,
* - a non-unique index sorted by car_model::manufacturer; note the
* non-standard manufacturer_extractor used.
* - a non-unique index sorted by car_model::price.
*/
typedef multi_index_container<
car_model,
indexed_by<
ordered_unique<
tag<model>,BOOST_MULTI_INDEX_MEMBER(car_model,std::string,model)
>,
ordered_non_unique<
tag<manufacturer>,
key_from_key<
BOOST_MULTI_INDEX_MEMBER(car_manufacturer,const std::string,name),
BOOST_MULTI_INDEX_MEMBER(
car_model,const car_manufacturer *,manufacturer)
>
>,
ordered_non_unique<
tag<price>,BOOST_MULTI_INDEX_MEMBER(car_model,int,price)
>
>
> car_table;
/* We call a *view* to a multi_index_container storing pointers instead of
* actual objects. These views are used in the complex search performed
* in the program. Resorting to multi_index of pointers eliminates
* unnecessary copying of objects, and provides us with an opportunity
* to show how BOOST_MULTI_INDEX_MEMBER can be used with pointer
* type elements.
* car_table_price_view indexes (pointers to) car_models by price.
*/
typedef multi_index_container<
const car_model*,
indexed_by<
ordered_non_unique<BOOST_MULTI_INDEX_MEMBER(car_model,const int,price)>
>
> car_table_price_view;
/* car_table_manufacturer_view indexes (pointers to) car_models by
* manufacturer
*/
typedef multi_index_container<
const car_model*,
indexed_by<
ordered_non_unique<
key_from_key<
BOOST_MULTI_INDEX_MEMBER(car_manufacturer,const std::string,name),
BOOST_MULTI_INDEX_MEMBER(
car_model,const car_manufacturer * const,manufacturer)
>
>
>
> car_table_manufacturer_view;
int main()
{
car_manufacturer_table cmt;
/* Fill the car_manufacturer table and keep pointers to the
* elements inserted.
*/
const car_manufacturer * cadillac=
&*(cmt.insert(car_manufacturer("Cadillac")).first);
const car_manufacturer * ford =
&*(cmt.insert(car_manufacturer("Ford")).first);
const car_manufacturer * bmw =
&*(cmt.insert(car_manufacturer("BMW")).first);
const car_manufacturer * audi =
&*(cmt.insert(car_manufacturer("Audi")).first);
car_table ct;
/* Fill the car_model_table. We use the previously initialized
* pointers to the elements of cmt.
*/
ct.insert(car_model("XLR",cadillac,76200));
ct.insert(car_model("SRX",cadillac,38690));
ct.insert(car_model("CTS",cadillac,30695));
ct.insert(car_model("Escalade",cadillac,54770));
ct.insert(car_model("ESV",cadillac,57195));
ct.insert(car_model("EXT",cadillac,52045));
ct.insert(car_model("Deville",cadillac,45195));
ct.insert(car_model("Seville",cadillac,46330));
ct.insert(car_model("ZX2",ford,15355));
ct.insert(car_model("Thunderbird",ford,43995));
ct.insert(car_model("Windstar",ford,35510));
ct.insert(car_model("Focus",ford,19630));
ct.insert(car_model("Taurus",ford,24290));
ct.insert(car_model("Mustang",ford,39900));
ct.insert(car_model("Crown Victoria",ford,30370));
ct.insert(car_model("325i",bmw,27800));
ct.insert(car_model("545i",bmw,54300));
ct.insert(car_model("745i",bmw,68500));
ct.insert(car_model("M3 coupe",bmw,46500));
ct.insert(car_model("Z4 roadster 3.0i",bmw,40250));
ct.insert(car_model("X5 4.4i",bmw,49950));
ct.insert(car_model("A4 1.8T",audi,25940));
ct.insert(car_model("TT Coupe",audi,33940));
ct.insert(car_model("A6 3.0",audi,36640));
ct.insert(car_model("Allroad quattro 2.7T",audi,40640));
ct.insert(car_model("A8 L",audi,69190));
std::cout<<"enter a car manufacturer"<<std::endl;
std::string cm;
std::getline(std::cin,cm);
/* check for manufacturer */
car_manufacturer_table::iterator icm=cmt.find(cm);
if(icm==cmt.end()){
std::cout<<"no such manufacturer in the table"<<std::endl;
return 0;
}
std::cout<<"enter a minimum price"<<std::endl;
int min_price;
std::cin>>min_price;
std::cout<<"enter a maximum price"<<std::endl;
int max_price;
std::cin>>max_price;
{
/* method 1 */
/* find all the cars for the manufacturer given */
boost::multi_index::index<car_table,manufacturer>::type::iterator ic0,ic1;
boost::tuples::tie(ic0,ic1)=get<manufacturer>(ct).equal_range(cm);
/* construct a view (indexed by price) with these */
car_table_price_view ctpv;
while(ic0!=ic1){
ctpv.insert(&*ic0);
++ic0;
}
/* select the cars in the range given */
car_table_price_view::iterator ictpv0=ctpv.lower_bound(min_price);
car_table_price_view::iterator ictpv1=ctpv.upper_bound(max_price);
if(ictpv0==ictpv1){
std::cout<<"no cars in the range given"<<std::endl;
return 0;
}
/* list them */
std::cout<<"listing by method 1"<<std::endl;
while(ictpv0!=ictpv1){
std::cout<<**ictpv0;
++ictpv0;
}
std::cout<<std::endl;
}
{
/* method 2 will give the same results */
/* find the cars in the range given */
boost::multi_index::index<car_table,price>::type::iterator ic0,ic1;
ic0=get<price>(ct).lower_bound(min_price);
ic1=get<price>(ct).upper_bound(max_price);
/* construct a view with these */
car_table_manufacturer_view ctmv;
while(ic0!=ic1){
ctmv.insert(&*ic0);
++ic0;
}
/* select the cars with given manufacturer */
car_table_manufacturer_view::iterator ictmv0,ictmv1;
boost::tuples::tie(ictmv0,ictmv1)=ctmv.equal_range(cm);
if(ictmv0==ictmv1){
std::cout<<"no cars in the range given"<<std::endl;
return 0;
}
/* list them */
std::cout<<"listing by method 2"<<std::endl;
while(ictmv0!=ictmv1){
std::cout<<**ictmv0;
++ictmv0;
}
std::cout<<std::endl;
}
return 0;
}