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//    notice, this list of conditions and the following disclaimer.
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//    notice, this list of conditions and the following disclaimer in the
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//    contributors may be used to endorse or promote products derived
//    from this software without specific prior written permission.
//
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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// Copyright (c) 2008-2024 NVIDIA Corporation. All rights reserved.

#ifndef NV_NSFOUNDATION_NSHASHMAP_H
#define NV_NSFOUNDATION_NSHASHMAP_H

#include "NsHashInternals.h"

// TODO: make this doxy-format
//
// This header defines two hash maps. Hash maps
// * support custom initial table sizes (rounded up internally to power-of-2)
// * support custom static allocator objects
// * auto-resize, based on a load factor (i.e. a 64-entry .75 load factor hash will resize
//                                        when the 49th element is inserted)
// * are based on open hashing
// * have O(1) contains, erase
//
// Maps have STL-like copying semantics, and properly initialize and destruct copies of objects
//
// There are two forms of map: coalesced and uncoalesced. Coalesced maps keep the entries in the
// initial segment of an array, so are fast to iterate over; however deletion is approximately
// twice as expensive.
//
// HashMap<T>:
//      bool            insert(const Key& k, const Value& v)    O(1) amortized (exponential resize policy)
//      Value &         operator[](const Key& k)                O(1) for existing objects, else O(1) amortized
//      const Entry *   find(const Key& k);                     O(1)
//      bool            erase(const T& k);                      O(1)
//      uint32_t            size();                                 constant
//      void            reserve(uint32_t size);                 O(MAX(currentOccupancy,size))
//      void            clear();                                O(currentOccupancy) (with zero constant for objects
// without
// destructors)
//      Iterator        getIterator();
//
// operator[] creates an entry if one does not exist, initializing with the default constructor.
// CoalescedHashMap<T> does not support getIterator, but instead supports
//      const Key *getEntries();
//
// Use of iterators:
//
// for(HashMap::Iterator iter = test.getIterator(); !iter.done(); ++iter)
//          myFunction(iter->first, iter->second);

namespace nvidia
{
namespace shdfnd
{
template <class Key, class Value, class HashFn = Hash<Key>, class Allocator = NonTrackingAllocator>
class HashMap : public internal::HashMapBase<Key, Value, HashFn, Allocator>
{
  public:
    typedef internal::HashMapBase<Key, Value, HashFn, Allocator> HashMapBase;
    typedef typename HashMapBase::Iterator Iterator;

    HashMap(uint32_t initialTableSize = 64, float loadFactor = 0.75f) : HashMapBase(initialTableSize, loadFactor)
    {
    }
    HashMap(uint32_t initialTableSize, float loadFactor, const Allocator& alloc)
    : HashMapBase(initialTableSize, loadFactor, alloc)
    {
    }
    HashMap(const Allocator& alloc) : HashMapBase(64, 0.75f, alloc)
    {
    }
    Iterator getIterator()
    {
        return Iterator(HashMapBase::mBase);
    }
};

template <class Key, class Value, class HashFn = Hash<Key>, class Allocator = NonTrackingAllocator>
class CoalescedHashMap : public internal::HashMapBase<Key, Value, HashFn, Allocator>
{
  public:
    typedef internal::HashMapBase<Key, Value, HashFn, Allocator> HashMapBase;

    CoalescedHashMap(uint32_t initialTableSize = 64, float loadFactor = 0.75f)
    : HashMapBase(initialTableSize, loadFactor)
    {
    }
    const Pair<const Key, Value>* getEntries() const
    {
        return HashMapBase::mBase.getEntries();
    }
};

} // namespace shdfnd
} // namespace nvidia

#endif // #ifndef NV_NSFOUNDATION_NSHASHMAP_H
