amxmodx/public/amtl/am-hashmap.h

// vim: set sts=8 ts=2 sw=2 tw=99 et:
//
// Copyright (C) 2013, David Anderson and AlliedModders LLC
// 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.
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//  may be used to endorse or promote products derived from this software
//  without specific prior written permission.
//
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#ifndef _include_amtl_hashmap_h_
#define _include_amtl_hashmap_h_

#include <am-hashtable.h>

namespace ke {

// Template parameters:
//
// K - Key type.
// V - Value type.
// HashPolicy - A struct with a hash and comparator function for each lookup type:
//     static uint32_t hash(const Type &value);
//     static bool matches(const Type &value, const K &key);
//
// All types that match a given key, must compute the same hash.
//
// Note that like HashTable, a HashMap is not usable until init() has been called.
template <typename K,
          typename V,
          typename HashPolicy,
          typename AllocPolicy = SystemAllocatorPolicy>
class HashMap : public AllocPolicy
{
 private:
  struct Entry
  {
    K key;
    V value;

    Entry()
    {}
    Entry(const Entry &other)
      : key(other.key),
        value(other.value)
    {}
    Entry(Entry &&other)
      : key(ke::Move(other.key)),
        value(ke::Move(other.value))
    {}

    template <typename UK, typename UV>
    Entry(UK &&aKey, UV &&aValue)
     : key(ke::Forward<UK>(aKey)),
       value(ke::Forward<UV>(aValue))
    { }
  };

  struct Policy
  {
    typedef Entry Payload;

    template <typename Lookup>
    static uint32_t hash(const Lookup &key) {
      return HashPolicy::hash(key);
    }

    template <typename Lookup>
    static bool matches(const Lookup &key, const Payload &payload) {
      return HashPolicy::matches(key, payload.key);
    }
  };

  typedef HashTable<Policy, AllocPolicy> Internal;

 public:
  HashMap(AllocPolicy ap = AllocPolicy())
    : table_(ap)
  {
  }

  // capacity must be a power of two.
  bool init(size_t capacity = 16) {
    return table_.init(capacity);
  }

  typedef typename Internal::Result Result;
  typedef typename Internal::Insert Insert;
  typedef typename Internal::iterator iterator;

  template <typename Lookup>
  Result find(const Lookup &key) {
    return table_.find(key);
  }

  template <typename Lookup>
  Insert findForAdd(const Lookup &key) {
    return table_.findForAdd(key);
  }

  template <typename Lookup>
  void removeIfExists(const Lookup &key) {
    return table_.remove(key);
  }

  void remove(Result &r) {
    table_.remove(r);
  }

  // The map must not have been mutated in between findForAdd() and add().
  // The Insert object is still valid after add() returns, however.
  template <typename UK, typename UV>
  bool add(Insert &i, UK &&key, UV &&value) {
    Entry entry(ke::Forward<UK>(key), ke::Forward<UV>(value));
    return table_.add(i, ke::Move(entry));
  }
  template <typename UK>
  bool add(Insert &i, UK &&key) {
    Entry entry(ke::Forward<UK>(key), V());
    return table_.add(i, ke::Move(entry));
  }

  // This can be used to avoid compiler constructed temporaries, since AMTL
  // does not yet support move semantics. If you use this, the key and value
  // must be set after.
  bool add(Insert &i) {
    return table_.add(i);
  }

  iterator iter() {
    return iterator(&table_);
  }

  void clear() {
    table_.clear();
  }

  size_t elements() const {
    return table_.elements();
  }

  size_t estimateMemoryUse() const {
    return table_.estimateMemoryUse();
  }

 private:
  Internal table_;
};

template <typename T>
struct PointerPolicy
{
  static inline uint32_t hash(T *p) {
    return HashPointer(p);
  }
  static inline bool matches(T *p1, T *p2) {
    return p1 == p2;
  }
};

}

#endif // _include_amtl_hashmap_h_