/usr/include/dballe/core/stlutils.h is in libdballe-dev 7.7-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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* core/stlutils - Useful functions to work with the STL
*
* Copyright (C) 2013 ARPA-SIM <urpsim@smr.arpa.emr.it>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* Author: Enrico Zini <enrico@enricozini.com>
*/
#ifndef DBA_CORE_STLUTILS_H
#define DBA_CORE_STLUTILS_H
#include <vector>
#include <set>
#include <memory>
namespace dballe {
namespace stl {
namespace stlutils {
template<typename T>
struct Sequence
{
virtual ~Sequence() {}
virtual bool valid() const = 0;
virtual const T& get() const = 0;
virtual void next() = 0;
};
} // back to dballe::stl
/// List of ranges
template<typename T>
struct Sequences : public std::vector<stlutils::Sequence<T>*>
{
typedef typename std::vector<stlutils::Sequence<T>*>::iterator iterator;
typedef typename std::vector<stlutils::Sequence<T>*>::const_iterator const_iterator;
Sequences() {}
~Sequences()
{
for (iterator i = this->begin(); i != this->end(); ++i)
delete *i;
}
/// Add a singleton set
void add_singleton(const T& val);
// Add a begin-end range
template<typename ITER>
void add(const ITER& begin, const ITER& end);
// Add a container's begin()-end() range
template<typename C>
void add(const C& container);
void add(std::unique_ptr< stlutils::Sequence<T> >& sequence);
// Add the union of the given sequences
void add_union(std::unique_ptr< Sequences<T> >& sequences);
// Add the union of the given sequences
void add_intersection(std::unique_ptr< Sequences<T> >& sequences);
private:
Sequences(const Sequences&);
Sequences& operator=(const Sequences&);
};
namespace stlutils {
template<typename T>
struct SequenceGenerator
{
Sequences<T>* sequences;
SequenceGenerator() : sequences(0) {}
SequenceGenerator(const SequenceGenerator<T>& sg) : sequences(sg.sequences)
{
// unique_ptr semantics
const_cast<SequenceGenerator<T>*>(&sg)->sequences = 0;
}
SequenceGenerator(std::unique_ptr< Sequences<T> >& sequences) : sequences(sequences.release()) {}
~SequenceGenerator() { if (sequences) delete sequences; }
SequenceGenerator<T>& operator=(const SequenceGenerator<T>& sg)
{
// unique_ptr semantics
if (&sg == this) return this;
if (sequences) delete sequences;
sequences = sg.sequences;
const_cast<SequenceGenerator<T>*>(&sg)->sequences = 0;
return *this;
}
void clear()
{
if (sequences) delete sequences;
sequences = 0;
}
bool has_items() const { return sequences != 0; }
bool operator==(const SequenceGenerator<T>& i) const
{
if (sequences == i.sequences) return true;
if (!sequences || !i.sequences) return false;
return *sequences == *i.sequences;
}
bool operator!=(const SequenceGenerator<T>& i) const
{
if (sequences == i.sequences) return false;
if (!sequences || !i.sequences) return true;
return *sequences != *i.sequences;
}
};
template<typename T>
struct Itersection : public SequenceGenerator<T>, public std::iterator<std::forward_iterator_tag, T>
{
Itersection() {}
Itersection(const Itersection<T>& sg) : SequenceGenerator<T>(sg) {}
Itersection(std::unique_ptr< Sequences<T> >& sequences)
: SequenceGenerator<T>(sequences)
{
sync_iters();
}
const T& get() const { return (*this->sequences)[0]->get(); }
void advance()
{
(*this->sequences)[0]->next();
sync_iters();
}
// Advance iterators so that they all point to items of the same value,
// or so that we become the end iterator
void sync_iters();
const T& operator*() const { return this->get(); }
Itersection<T>& operator++()
{
this->advance();
return *this;
}
};
template<typename T>
struct Iterunion : public SequenceGenerator<T>, public std::iterator<std::forward_iterator_tag, T>
{
const T* minval;
Iterunion() {}
Iterunion(const Iterunion<T>& sg)
: SequenceGenerator<T>(sg), minval(sg.minval)
{
// unique_ptr semantics
const_cast<Iterunion<T>*>(&sg)->minval = 0;
}
Iterunion(std::unique_ptr< Sequences<T> >& sequences)
: SequenceGenerator<T>(sequences), minval(0)
{
find_min();
}
Iterunion<T>& operator=(const Iterunion<T>& sg)
{
// unique_ptr semantics
SequenceGenerator<T>::operator=(sg);
minval = sg.minval;
const_cast<Iterunion<T>*>(&sg)->minval = 0;
return *this;
}
const T& get() const { return *minval; }
/**
* Find the next minimum value.
*
* If minval is 0, set it to the minimum value.
* If minval points to an element, advance all sequences that have that
* element as minimum value, and set minval to the next minimum value.
*
* Returns false when all sequences are exausted; true if a new minimum
* value was found.
*/
void find_min();
const T& operator*() const { return this->get(); }
Iterunion<T>& operator++()
{
this->find_min();
return *this;
}
};
}
/**
* Virtual container containing the intersection of an arbitrary number of
* sorted (begin, end) sequences.
*/
template<class T>
class Intersection
{
public:
typedef stlutils::Itersection<T> const_iterator;
const_iterator begin(std::unique_ptr< Sequences<T> >& sequences) const
{
return const_iterator(sequences);
}
const_iterator end() const
{
return const_iterator();
}
};
template<typename T>
class SetIntersection
{
protected:
std::vector<const std::set<T>*> sets;
Intersection<T> intersection;
public:
void add(const std::set<T>& set)
{
sets.push_back(&set);
}
typedef typename Intersection<T>::const_iterator const_iterator;
const_iterator begin()
{
std::unique_ptr< Sequences<T> > sequences(new Sequences<T>);
// Look for the highest first element in all sets
bool first = true;
T max_of_first;
for (typename std::vector<const std::set<T>*>::const_iterator i = sets.begin();
i != sets.end(); ++i)
{
const std::set<T>& s = **i;
// If one of the sets is empty, then the intersection is empty
if (s.begin() == s.end()) return end();
if (first)
{
max_of_first = *s.begin();
first = false;
} else {
if (max_of_first < *s.begin())
max_of_first = *s.begin();
}
}
// Populate intersection with all the ranges we intersect
for (typename std::vector<const std::set<T>*>::const_iterator i = sets.begin();
i != sets.end(); ++i)
{
const std::set<T>& s = **i;
sequences->add(s.lower_bound(max_of_first), s.end());
}
return intersection.begin(sequences);
}
const_iterator end()
{
return intersection.end();
}
};
/**
* Virtual container containing the union of an arbitrary number of
* sorted (begin, end) sequences.
*/
template<class T>
class Union
{
public:
typedef stlutils::Iterunion<T> const_iterator;
const_iterator begin(std::unique_ptr< Sequences<T> >& sequences) const
{
return const_iterator(sequences);
}
const_iterator end() const
{
return const_iterator();
}
};
/**
* Similar to std::inserter, but just calls target.insert() without requiring
* it to have iterators at all.
*/
template<typename T>
class TrivialInserter : public std::iterator<std::output_iterator_tag, void, void, void, void>
{
protected:
T* target;
public:
TrivialInserter(T& target) : target(&target) {}
template<typename V>
V operator=(V val) { target->insert(val); return val; }
TrivialInserter& operator*() { return *this; }
TrivialInserter& operator++() { return *this; }
TrivialInserter& operator++(int) { return *this; }
};
template<typename T>
TrivialInserter<T> trivial_inserter(T& target)
{
return TrivialInserter<T>(target);
}
/**
* Similar to std::inserter, but just calls target.insert() without requiring
* it to have iterators at all.
*/
template<typename T>
class Pusher : public std::iterator<std::output_iterator_tag, void, void, void, void>
{
protected:
T* target;
public:
Pusher(T& target) : target(&target) {}
template<typename V>
V operator=(V val) { target->push(val); return val; }
Pusher& operator*() { return *this; }
Pusher& operator++() { return *this; }
Pusher& operator++(int) { return *this; }
};
template<typename T>
Pusher<T> pusher(T& target)
{
return Pusher<T>(target);
}
/**
* Similar to std::inserter, but just calls target.insert() without requiring
* it to have iterators at all.
*/
template<typename T>
class Eraser : public std::iterator<std::output_iterator_tag, void, void, void, void>
{
protected:
T* target;
public:
Eraser(T& target) : target(&target) {}
template<typename V>
V operator=(V val) { target->erase(val); return val; }
Eraser& operator*() { return *this; }
Eraser& operator++() { return *this; }
Eraser& operator++(int) { return *this; }
};
template<typename T>
Eraser<T> eraser(T& target)
{
return Eraser<T>(target);
}
}
}
#endif
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