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mlpack/fastlib/trilinos/include/Teuchos_HashSet.hpp
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// @HEADER
// ***********************************************************************
//
// Teuchos: Common Tools Package
// Copyright (2004) Sandia Corporation
//
// Under terms of Contract DE-AC04-94AL85000, there is a non-exclusive
// license for use of this work by or on behalf of the U.S. Government.
//
// This library is free software; you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation; either version 2.1 of the
// License, or (at your option) any later version.
//
// This library 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
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
// USA
// Questions? Contact Michael A. Heroux (maherou@sandia.gov)
//
// ***********************************************************************
// @HEADER
#ifndef TEUCHOS_HASHSET_H
#define TEUCHOS_HASHSET_H
/*! \file Teuchos_HashSet.hpp
\brief Templated hashtable-based set
*/
#include "Teuchos_ConfigDefs.hpp"
#include "Teuchos_Array.hpp"
#include "Teuchos_HashUtils.hpp"
namespace Teuchos
{
using std::string;
/** \ingroup Containers
* \brief Templated hashtable-based set.
HashSet is a hashtable-based set, similar to the STL set class
* or the Java HashSet class.
*/
template<class Key> class HashSet
{
public:
//! Create an empty HashSet
inline HashSet(int capacity=19);
//! Check for the presence of a key
inline bool containsKey(const Key& key) const ;
//! Put a new object into the table.
inline void put(const Key& key);
//! Remove from the table the element given by key.
inline void remove(const Key& key);
//! Get the number of elements in the table
inline int size() const {return count_;}
//! Get list of keys in Array form
inline Array<Key> arrayify() const ;
//! Get list of keys in Array form
inline void arrayify(Array<Key>& keys) const ;
//! Write to a std::string
inline std::string toString() const ;
private:
/** rebuild the hashtable when the size has changed */
inline void rehash();
/** get the next prime number near a given capacity */
inline int nextPrime(int newCap) const ;
Array<Array<Key> > data_;
int count_;
int capacity_;
mutable Key mostRecentKey_;
};
/** \relates HashSet
\brief Write HashSet to a stream
*/
template<class Key>
std::ostream& operator<<(std::ostream& os, const HashSet<Key>& h);
template<class Key> inline
std::string toString(const HashSet<Key>& h) {return h.toString();}
template<class Key> inline
HashSet<Key>::HashSet(int capacity)
: data_(), count_(0), capacity_(HashUtils::nextPrime(capacity))
{
data_.resize(capacity_);
}
template<class Key> inline
bool HashSet<Key>::containsKey(const Key& key) const
{
const Array<Key>& candidates
= data_[hashCode(key) % capacity_];
for (int i=0; i<candidates.length(); i++)
{
const Key& c = candidates[i];
if (c == key)
{
return true;
}
}
return false;
}
template<class Key> inline
void HashSet<Key>::put(const Key& key)
{
int index = hashCode(key) % capacity_;
Array<Key>& local = data_[index];
// check for duplicate key
for (int i=0; i<local.length(); i++)
{
if (local[i] == key)
{
return;
}
}
// no duplicate key, so increment element count by one.
count_++;
// check for need to resize.
if (count_ > capacity_)
{
capacity_ = HashUtils::nextPrime(capacity_+1);
rehash();
// recaluate index
index = hashCode(key) % capacity_;
}
data_[index].append(key);
}
template<class Key> inline
void HashSet<Key>::rehash()
{
Array<Array<Key> > tmp(capacity_);
for (int i=0; i<data_.length(); i++)
{
for (int j=0; j<data_[i].length(); j++)
{
int newIndex = hashCode(data_[i][j]) % capacity_;
tmp[newIndex].append(data_[i][j]);
}
}
data_ = tmp;
}
template<class Key> inline
Array<Key> HashSet<Key>::arrayify() const
{
Array<Key> rtn;
rtn.reserve(size());
for (int i=0; i<data_.length(); i++)
{
for (int j=0; j<data_[i].length(); j++)
{
rtn.append(data_[i][j]);
}
}
return rtn;
}
template<class Key> inline
void HashSet<Key>::arrayify(Array<Key>& rtn) const
{
rtn.resize(0);
for (int i=0; i<data_.length(); i++)
{
for (int j=0; j<data_[i].length(); j++)
{
rtn.append(data_[i][j]);
}
}
}
template<class Key> inline
std::string HashSet<Key>::toString() const
{
std::string rtn = "HashSet[";
bool first = true;
for (int i=0; i<data_.length(); i++)
{
for (int j=0; j<data_[i].length(); j++)
{
if (!first) rtn += ", ";
first = false;
rtn += Teuchos::toString(data_[i][j]);
}
}
rtn += "]";
return rtn;
}
template<class Key> inline
void HashSet<Key>::remove(const Key& key)
{
TEST_FOR_EXCEPTION(!containsKey(key),
std::runtime_error,
"HashSet<Key>::remove: key "
<< Teuchos::toString(key)
<< " not found in HashSet"
<< toString());
count_--;
int h = hashCode(key) % capacity_;
Array<Key>& candidates = data_[h];
for (int i=0; i<candidates.length(); i++)
{
if (candidates[i] == key)
{
candidates.remove(i);
break;
}
}
}
template<class Key> inline
std::ostream& operator<<(std::ostream& os, const HashSet<Key>& h)
{
return os << h.toString();
}
}
#endif // TEUCHOS_HASHSET_H