#ifndef SHARECONTAINER_H
#define SHARECONTAINER_H
+#include <boost/utility.hpp>
+#include <boost/shared_ptr.hpp>
+
#include <vector>
#include <algorithm>
#include <functional>
-#include <boost/utility.hpp>
-#include <boost/smart_ptr.hpp>
-///
+/// Share objects between several users.
+/**
+ This class can be used to reduce memory consuption when you have a lot
+ of equal objects used all over your code.
+
+ \author Lars Gullik Bjønnes
+*/
template<class Share>
-class ShareContainer : public noncopyable {
+class ShareContainer : boost::noncopyable {
public:
///
typedef std::vector<boost::shared_ptr<Share> > Params;
///
typedef typename Params::value_type value_type;
- ///
+ /// Return a shared_ptr that points to a element equal to ps.
value_type
get(Share const & ps) const {
// First see if we already have this ps in the container
- Params::iterator it = std::find_if(params.begin(),
- params.end(),
- isEqual(ps));
+ typename Params::iterator it = std::find_if(params.begin(),
+ params.end(),
+ isEqual(ps));
value_type tmp;
if (it == params.end()) {
// ok we don't have it so we should
// some (one) unique elemements some times
// but we should gain a lot in speed.
clean();
- //std::sort(params.rbegin(), params.rend(), comp());
} else {
// yes we have it already
tmp = *it;
- // move it forward
+ // move it forward - optimization
+ // makes the next find faster.
if (it != params.begin())
- swap(*it, *(it - 1));
+ std::swap(*it, *(it - 1));
}
return tmp;
}
private:
- ///
+ /// A functor returning true if the elements are equal.
struct isEqual {
isEqual(Share const & s) : p_(s) {}
bool operator()(value_type const & p1) const {
private:
Share const & p_;
};
- ///
- //struct comp {
- // int operator()(value_type const & p1,
- // value_type const & p2) const {
- // return p1.use_count() < p2.use_count();
- // }
- //};
- ///
+ /// A functor returning true if the element is unique.
struct isUnique {
bool operator()(value_type const & p) const {
return p.unique();
}
};
-
- ///
+
+ /** Remove all unique items.
+ This removes all elements from params that is only referenced
+ from the private container. This can be considered a memory
+ optimizaton.
+ */
void clean() const {
- // Remove all unique items. (i.e. entries that only
- // exists in the conatainer and does not have a
- // corresponding paragrah.
- Params::iterator it = std::remove_if(params.begin(),
- params.end(),
- isUnique());
+ typename Params::iterator it = std::remove_if(params.begin(),
+ params.end(),
+ isUnique());
params.erase(it, params.end());
}
-
- ///
+
+ /// The actual container.
mutable Params params;
};
#endif