/*
 * Copyright (C) 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 */

#ifndef WTF_HashMap_h
#define WTF_HashMap_h

#include <wtf/HashTable.h>

namespace WTF
{

template<typename PairType> struct PairFirstExtractor;

template<typename KeyArg, typename MappedArg, typename HashArg = typename DefaultHash<KeyArg>::Hash,
         typename KeyTraitsArg = HashTraits<KeyArg>, typename MappedTraitsArg = HashTraits<MappedArg> >
class HashMap
{
private:
    typedef KeyTraitsArg KeyTraits;
    typedef MappedTraitsArg MappedTraits;
    typedef PairHashTraits<KeyTraits, MappedTraits> ValueTraits;

public:
    typedef typename KeyTraits::TraitType KeyType;
    typedef typename MappedTraits::TraitType MappedType;
    typedef typename ValueTraits::TraitType ValueType;

private:
    typedef HashArg HashFunctions;

    typedef HashTable<KeyType, ValueType, PairFirstExtractor<ValueType>,
            HashFunctions, ValueTraits, KeyTraits> HashTableType;

public:
    typedef HashTableIteratorAdapter<HashTableType, ValueType> iterator;
    typedef HashTableConstIteratorAdapter<HashTableType, ValueType> const_iterator;

    void swap(HashMap &);

    int size() const;
    int capacity() const;
    bool isEmpty() const;

    // iterators iterate over pairs of keys and values
    iterator begin();
    iterator end();
    const_iterator begin() const;
    const_iterator end() const;

    iterator find(const KeyType &);
    const_iterator find(const KeyType &) const;
    bool contains(const KeyType &) const;
    MappedType get(const KeyType &) const;

    // replaces value but not key if key is already present
    // return value is a pair of the iterator to the key location,
    // and a boolean that's true if a new value was actually added
    pair<iterator, bool> set(const KeyType &, const MappedType &);

    // does nothing if key is already present
    // return value is a pair of the iterator to the key location,
    // and a boolean that's true if a new value was actually added
    pair<iterator, bool> add(const KeyType &, const MappedType &);

    void remove(const KeyType &);
    void remove(iterator);
    void clear();

    MappedType take(const KeyType &); // efficient combination of get with remove

private:
    pair<iterator, bool> inlineAdd(const KeyType &, const MappedType &);

    HashTableType m_impl;
};

template<typename PairType> struct PairFirstExtractor {
    static const typename PairType::first_type &extract(const PairType &p)
    {
        return p.first;
    }
};

template<typename ValueType, typename ValueTraits, typename HashFunctions>
struct HashMapTranslator {
    typedef typename ValueType::first_type KeyType;
    typedef typename ValueType::second_type MappedType;

    static unsigned hash(const KeyType &key)
    {
        return HashFunctions::hash(key);
    }
    static bool equal(const KeyType &a, const KeyType &b)
    {
        return HashFunctions::equal(a, b);
    }
    static void translate(ValueType &location, const KeyType &key, const MappedType &mapped)
    {
        location.first = key;
        location.second = mapped;
    }
};

template<typename T, typename U, typename V, typename W, typename X>
inline void HashMap<T, U, V, W, X>::swap(HashMap &other)
{
    m_impl.swap(other.m_impl);
}

template<typename T, typename U, typename V, typename W, typename X>
inline int HashMap<T, U, V, W, X>::size() const
{
    return m_impl.size();
}

template<typename T, typename U, typename V, typename W, typename X>
inline int HashMap<T, U, V, W, X>::capacity() const
{
    return m_impl.capacity();
}

template<typename T, typename U, typename V, typename W, typename X>
inline bool HashMap<T, U, V, W, X>::isEmpty() const
{
    return m_impl.isEmpty();
}

template<typename T, typename U, typename V, typename W, typename X>
inline typename HashMap<T, U, V, W, X>::iterator HashMap<T, U, V, W, X>::begin()
{
    return m_impl.begin();
}

template<typename T, typename U, typename V, typename W, typename X>
inline typename HashMap<T, U, V, W, X>::iterator HashMap<T, U, V, W, X>::end()
{
    return m_impl.end();
}

template<typename T, typename U, typename V, typename W, typename X>
inline typename HashMap<T, U, V, W, X>::const_iterator HashMap<T, U, V, W, X>::begin() const
{
    return m_impl.begin();
}

template<typename T, typename U, typename V, typename W, typename X>
inline typename HashMap<T, U, V, W, X>::const_iterator HashMap<T, U, V, W, X>::end() const
{
    return m_impl.end();
}

template<typename T, typename U, typename V, typename W, typename X>
inline typename HashMap<T, U, V, W, X>::iterator HashMap<T, U, V, W, X>::find(const KeyType &key)
{
    return m_impl.find(key);
}

template<typename T, typename U, typename V, typename W, typename X>
inline typename HashMap<T, U, V, W, X>::const_iterator HashMap<T, U, V, W, X>::find(const KeyType &key) const
{
    return m_impl.find(key);
}

template<typename T, typename U, typename V, typename W, typename X>
inline bool HashMap<T, U, V, W, X>::contains(const KeyType &key) const
{
    return m_impl.contains(key);
}

template<typename T, typename U, typename V, typename W, typename X>
inline pair<typename HashMap<T, U, V, W, X>::iterator, bool>
HashMap<T, U, V, W, X>::inlineAdd(const KeyType &key, const MappedType &mapped)
{
    typedef HashMapTranslator<ValueType, ValueTraits, HashFunctions> TranslatorType;
    return m_impl.template add<KeyType, MappedType, TranslatorType>(key, mapped);
}

template<typename T, typename U, typename V, typename W, typename X>
pair<typename HashMap<T, U, V, W, X>::iterator, bool>
HashMap<T, U, V, W, X>::set(const KeyType &key, const MappedType &mapped)
{
    pair<iterator, bool> result = inlineAdd(key, mapped);
    if (!result.second) {
        // add call above didn't change anything, so set the mapped value
        result.first->second = mapped;
    }
    return result;
}

template<typename T, typename U, typename V, typename W, typename X>
pair<typename HashMap<T, U, V, W, X>::iterator, bool>
HashMap<T, U, V, W, X>::add(const KeyType &key, const MappedType &mapped)
{
    return inlineAdd(key, mapped);
}

template<typename T, typename U, typename V, typename W, typename MappedTraits>
typename HashMap<T, U, V, W, MappedTraits>::MappedType
HashMap<T, U, V, W, MappedTraits>::get(const KeyType &key) const
{
    ValueType *entry = const_cast<HashTableType &>(m_impl).lookup(key);
    if (!entry) {
        return MappedTraits::emptyValue();
    }
    return entry->second;
}

template<typename T, typename U, typename V, typename W, typename X>
inline void HashMap<T, U, V, W, X>::remove(iterator it)
{
    if (it.m_impl == m_impl.end()) {
        return;
    }
    m_impl.checkTableConsistency();
    m_impl.removeWithoutEntryConsistencyCheck(it.m_impl);
}

template<typename T, typename U, typename V, typename W, typename X>
inline void HashMap<T, U, V, W, X>::remove(const KeyType &key)
{
    remove(find(key));
}

template<typename T, typename U, typename V, typename W, typename X>
inline void HashMap<T, U, V, W, X>::clear()
{
    m_impl.clear();
}

template<typename T, typename U, typename V, typename W, typename MappedTraits>
typename HashMap<T, U, V, W, MappedTraits>::MappedType
HashMap<T, U, V, W, MappedTraits>::take(const KeyType &key)
{
    // This can probably be made more efficient to avoid ref/deref churn.
    iterator it = find(key);
    if (it == end()) {
        return MappedTraits::emptyValue();
    }
    typename HashMap<T, U, V, W, MappedTraits>::MappedType result = it->second;
    remove(it);
    return result;
}

template<typename T, typename U, typename V, typename W, typename X>
bool operator==(const HashMap<T, U, V, W, X> &a, const HashMap<T, U, V, W, X> &b)
{
    if (a.size() != b.size()) {
        return false;
    }

    typedef typename HashMap<T, U, V, W, X>::const_iterator const_iterator;

    const_iterator end = a.end();
    const_iterator notFound = b.end();
    for (const_iterator it = a.begin(); it != end; ++it) {
        const_iterator bPos = b.find(it->first);
        if (bPos == notFound || it->second != bPos->second) {
            return false;
        }
    }

    return true;
}

template<typename T, typename U, typename V, typename W, typename X>
inline bool operator!=(const HashMap<T, U, V, W, X> &a, const HashMap<T, U, V, W, X> &b)
{
    return !(a == b);
}

template<typename MappedType, typename HashTableType>
void deleteAllPairSeconds(HashTableType &collection)
{
    typedef typename HashTableType::const_iterator iterator;
    iterator end = collection.end();
    for (iterator it = collection.begin(); it != end; ++it) {
        delete it->second;
    }
}

template<typename T, typename U, typename V, typename W, typename X>
inline void deleteAllValues(const HashMap<T, U, V, W, X> &collection)
{
    deleteAllPairSeconds<typename HashMap<T, U, V, W, X>::MappedType>(collection);
}

template<typename KeyType, typename HashTableType>
void deleteAllPairFirsts(HashTableType &collection)
{
    typedef typename HashTableType::const_iterator iterator;
    iterator end = collection.end();
    for (iterator it = collection.begin(); it != end; ++it) {
        delete it->first;
    }
}

template<typename T, typename U, typename V, typename W, typename X>
inline void deleteAllKeys(const HashMap<T, U, V, W, X> &collection)
{
    deleteAllPairFirsts<typename HashMap<T, U, V, W, X>::KeyType>(collection);
}

template<typename T, typename U, typename V, typename W, typename X, typename Y>
inline void copyKeysToVector(const HashMap<T, U, V, W, X> &collection, Y &vector)
{
    typedef typename HashMap<T, U, V, W, X>::const_iterator::Keys iterator;

    vector.resize(collection.size());

    iterator it = collection.begin().keys();
    iterator end = collection.end().keys();
    for (unsigned i = 0; it != end; ++it, ++i) {
        vector[i] = *it;
    }
}

template<typename T, typename U, typename V, typename W, typename X, typename Y>
inline void copyValuesToVector(const HashMap<T, U, V, W, X> &collection, Y &vector)
{
    typedef typename HashMap<T, U, V, W, X>::const_iterator::Values iterator;

    vector.resize(collection.size());

    iterator it = collection.begin().values();
    iterator end = collection.end().values();
    for (unsigned i = 0; it != end; ++it, ++i) {
        vector[i] = *it;
    }
}

} // namespace WTF

using WTF::HashMap;

#include <wtf/RefPtrHashMap.h>

#endif /* WTF_HashMap_h */
