include/set

/* -*- c++ -*- */
/*
 * Copyright (C) 2010 The Android Open Source Project
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *  * Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  * Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef ANDROID_ASTL_SET__
#define ANDROID_ASTL_SET__

// To include bionic's stl_pair.h, __STL_*_NAMESPACE must be defined.
#ifndef __STL_BEGIN_NAMESPACE
#define __STL_BEGIN_NAMESPACE namespace std {
#define __STL_END_NAMESPACE   }
#endif

#include <stl_pair.h>
#include <iterator>
#include <vector>

namespace std {

#ifdef _Key
#error "_Key is a macro."
#endif

// Very basic and crude implementation of std::set.
//
// TODO: Replace the vector used to implement the set with an RB
// tree. vector does not implement insert and is not ordered as a
// result.

template<class _Key>
class set
{
  public:
    typedef _Key key_type;
    typedef _Key value_type;

  private:
    typedef vector<_Key> impl_type;
  public:
    typedef _Key*        pointer;
    typedef const _Key*  const_pointer;
    typedef _Key&        reference;
    typedef const _Key&  const_reference;

    typedef typename impl_type::iterator        iterator;
    typedef typename impl_type::const_iterator  const_iterator;
    typedef typename impl_type::size_type       size_type;
    typedef typename impl_type::difference_type difference_type;

    // Insert elt if and only if there is no element in the set
    // equivalent to elt already.
    // @param elt Element to be inserted.
    // @return A pair made of:
    //         - an iterator which points to the equivalent element in the set
    //           (either 'elt' or the one already present),
    //         - a bool which indicates if the insertion took place.
    pair<iterator, bool> insert(const value_type& elt) {
        typename impl_type::iterator i = mImpl.begin();
        while (i != mImpl.end()) {
            if (elt == *i) {
                return pair<iterator, bool>(i, false);
            }
            ++i;
        }
        mImpl.push_back(elt);
        return pair<iterator, bool>(--mImpl.end(), true);
    }

    // Set have an insert unique semantic so there is at most one
    // instance of the elt.
    // @param elt Element to locate.
    // @return 0 if elt was not found, 1 otherwise.
    size_type count(const key_type& elt) const {
        typename impl_type::const_iterator i = mImpl.begin();
        while (i != mImpl.end()) {
            if (elt == *i) {
                return 1;
            }
            ++i;
        }
        return 0;
    }

    // @return true if the set is empty, false otherwise.
    bool empty() const { return mImpl.size() == 0; }
    size_type size() const { return mImpl.size(); }

    iterator begin() { return mImpl.begin(); }
    iterator end() { return mImpl.end(); }

    const_iterator begin() const { return mImpl.begin(); }
    const_iterator end() const { return mImpl.end(); }

  private:
    impl_type mImpl;
};

}  // namespace std

#endif  // ANDROID_ASTL_VECTOR__