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products/sources/formale Sprachen/Java/Openjdk/src/hotspot/share/utilities/ (Sun/Oracle ^©) Datei vom 13.11.2022 mit Größe 9 kB

Quelle resourceHash.hpp Sprache: C

/*
* Copyright (c) 2012, 2022, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code 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 General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/

#ifndef SHARE_UTILITIES_RESOURCEHASH_HPP
#define SHARE_UTILITIES_RESOURCEHASH_HPP

#include "memory/allocation.hpp"
#include "utilities/globalDefinitions.hpp"
#include "utilities/numberSeq.hpp"
#include "utilities/tableStatistics.hpp"

template<typename K, typename V>
class ResourceHashtableNode : public AnyObj {
public:
  unsigned _hash;
  K _key;
  V _value;
  ResourceHashtableNode* _next;

  ResourceHashtableNode(unsigned hash, K const& key, V const& value) :
    _hash(hash), _key(key), _value(value), _next(NULL) {}

  // Create a node with a default-constructed value.
  ResourceHashtableNode(unsigned hash, K const& key) :
    _hash(hash), _key(key), _value(), _next(NULL) {}
};

template<
    class STORAGE,
    typename K, typename V,
    AnyObj::allocation_type ALLOC_TYPE,
    MEMFLAGS MEM_TYPE,
    unsigned (*HASH)  (K const&),
    bool     (*EQUALS)(K const&, K const&)
    >
class ResourceHashtableBase : public STORAGE {
  using Node = ResourceHashtableNode<K, V>;
private:
  int _number_of_entries;

  Node** bucket_at(unsigned index) {
    Node** t = table();
    return &t[index];
  }

  const Node* const* bucket_at(unsigned index) const {
    Node** t = table();
    return &t[index];
  }

  // Returns a pointer to where the node where the value would reside if
  // it's in the table.
  Node** lookup_node(unsigned hash, K const& key) {
    unsigned index = hash % table_size();
    Node** ptr = bucket_at(index);
    while (*ptr != NULL) {
      Node* node = *ptr;
      if (node->_hash == hash && EQUALS(key, node->_key)) {
        break;
      }
      ptr = &(node->_next);
    }
    return ptr;
  }

  Node const** lookup_node(unsigned hash, K const& key) const {
    return const_cast<Node const**>(
        const_cast<ResourceHashtableBase*>(this)->lookup_node(hash, key));
  }

protected:
  Node** table() const { return STORAGE::table(); }

  ResourceHashtableBase() : STORAGE(), _number_of_entries(0) {}
  ResourceHashtableBase(unsigned size) : STORAGE(size), _number_of_entries(0) {}
  NONCOPYABLE(ResourceHashtableBase);

  ~ResourceHashtableBase() {
    if (ALLOC_TYPE == AnyObj::C_HEAP) {
      Node* const* bucket = table();
      const unsigned sz = table_size();
      while (bucket < bucket_at(sz)) {
        Node* node = *bucket;
        while (node != NULL) {
          Node* cur = node;
          node = node->_next;
          delete cur;
        }
        ++bucket;
      }
    }
  }

public:
  unsigned table_size() const { return STORAGE::table_size(); }
  int number_of_entries() const { return _number_of_entries; }

  bool contains(K const& key) const {
    return get(key) != NULL;
  }

  V* get(K const& key) const {
    unsigned hv = HASH(key);
    Node const** ptr = lookup_node(hv, key);
    if (*ptr != NULL) {
      return const_cast<V*>(&(*ptr)->_value);
    } else {
      return NULL;
    }
  }

/**
  * Inserts or replaces a value in the table.
  * @return: true:  if a new item is added
  *          false: if the item already existed and the value is updated
  */
  bool put(K const& key, V const& value) {
    unsigned hv = HASH(key);
    Node** ptr = lookup_node(hv, key);
    if (*ptr != NULL) {
      (*ptr)->_value = value;
      return false;
    } else {
      if (ALLOC_TYPE == AnyObj::C_HEAP) {
        *ptr = new (MEM_TYPE) Node(hv, key, value);
      } else {
        *ptr = new Node(hv, key, value);
      }
      _number_of_entries ++;
      return true;
    }
  }

  // Look up the key.
  // If an entry for the key exists, leave map unchanged and return a pointer to its value.
  // If no entry for the key exists, create a new entry from key and a default-created value
  //  and return a pointer to the value.
  // *p_created is true if entry was created, false if entry pre-existed.
  V* put_if_absent(K const& key, bool* p_created) {
    unsigned hv = HASH(key);
    Node** ptr = lookup_node(hv, key);
    if (*ptr == NULL) {
      if (ALLOC_TYPE == AnyObj::C_HEAP) {
        *ptr = new (MEM_TYPE) Node(hv, key);
      } else {
        *ptr = new Node(hv, key);
      }
      *p_created = true;
      _number_of_entries ++;
    } else {
      *p_created = false;
    }
    return &(*ptr)->_value;
  }

  // Look up the key.
  // If an entry for the key exists, leave map unchanged and return a pointer to its value.
  // If no entry for the key exists, create a new entry from key and value and return a
  //  pointer to the value.
  // *p_created is true if entry was created, false if entry pre-existed.
  V* put_if_absent(K const& key, V const& value, bool* p_created) {
    unsigned hv = HASH(key);
    Node** ptr = lookup_node(hv, key);
    if (*ptr == NULL) {
      if (ALLOC_TYPE == AnyObj::C_HEAP) {
        *ptr = new (MEM_TYPE) Node(hv, key, value);
      } else {
        *ptr = new Node(hv, key, value);
      }
      *p_created = true;
      _number_of_entries ++;
    } else {
      *p_created = false;
    }
    return &(*ptr)->_value;
  }

  bool remove(K const& key) {
    unsigned hv = HASH(key);
    Node** ptr = lookup_node(hv, key);

    Node* node = *ptr;
    if (node != NULL) {
      *ptr = node->_next;
      if (ALLOC_TYPE == AnyObj::C_HEAP) {
        delete node;
      }
      _number_of_entries --;
      return true;
    }
    return false;
  }

  // ITER contains bool do_entry(K const&, V const&), which will be
  // called for each entry in the table.  If do_entry() returns false,
  // the iteration is cancelled.
  template<class ITER>
  void iterate(ITER* iter) const {
    auto function = [&] (K& k, V& v) {
      return iter->do_entry(k, v);
    };
    iterate(function);
  }

  template<typename Function>
  void iterate(Function function) const { // lambda enabled API
    Node* const* bucket = table();
    const unsigned sz = table_size();
    while (bucket < bucket_at(sz)) {
      Node* node = *bucket;
      while (node != NULL) {
        bool cont = function(node->_key, node->_value);
        if (!cont) { return; }
        node = node->_next;
      }
      ++bucket;
    }
  }

  // same as above, but unconditionally iterate all entries
  template<typename Function>
  void iterate_all(Function function) const { // lambda enabled API
    auto wrapper = [&] (K& k, V& v) {
      function(k, v);
      return true;
    };
    iterate(wrapper);
  }

  // ITER contains bool do_entry(K const&, V const&), which will be
  // called for each entry in the table.  If do_entry() returns true,
  // the entry is deleted.
  template<class ITER>
  void unlink(ITER* iter) {
    const unsigned sz = table_size();
    for (unsigned index = 0; index < sz; index++) {
      Node** ptr = bucket_at(index);
      while (*ptr != NULL) {
        Node* node = *ptr;
        // do_entry must clean up the key and value in Node.
        bool clean = iter->do_entry(node->_key, node->_value);
        if (clean) {
          *ptr = node->_next;
          if (ALLOC_TYPE == AnyObj::C_HEAP) {
            delete node;
          }
          _number_of_entries --;
        } else {
          ptr = &(node->_next);
        }
      }
    }
  }

  template<typename Function>
  TableStatistics statistics_calculate(Function size_function) const {
    NumberSeq summary;
    size_t literal_bytes = 0;
    Node* const* bucket = table();
    const unsigned sz = table_size();
    while (bucket < bucket_at(sz)) {
      Node* node = *bucket;
      int count = 0;
      while (node != NULL) {
        literal_bytes += size_function(node->_key, node->_value);
        count++;
        node = node->_next;
      }
      summary.add((double)count);
      ++bucket;
    }
    return TableStatistics(summary, literal_bytes, sizeof(Node*), sizeof(Node));
  }

};

template<unsigned TABLE_SIZE, typename K, typename V>
class FixedResourceHashtableStorage : public AnyObj {
  using Node = ResourceHashtableNode<K, V>;

  Node* _table[TABLE_SIZE];
protected:
  FixedResourceHashtableStorage() { memset(_table, 0, sizeof(_table)); }
  ~FixedResourceHashtableStorage() = default;

  constexpr unsigned table_size() const {
    return TABLE_SIZE;
  }

  Node** table() const {
    return const_cast<Node**>(_table);
  }
};

template<
    typename K, typename V,
    unsigned SIZE = 256,
    AnyObj::allocation_type ALLOC_TYPE = AnyObj::RESOURCE_AREA,
    MEMFLAGS MEM_TYPE = mtInternal,
    unsigned (*HASH)  (K const&)           = primitive_hash<K>,
    bool     (*EQUALS)(K const&, K const&) = primitive_equals<K>
    >
class ResourceHashtable : public ResourceHashtableBase<
  FixedResourceHashtableStorage<SIZE, K, V>,
    K, V, ALLOC_TYPE, MEM_TYPE, HASH, EQUALS> {
  NONCOPYABLE(ResourceHashtable);
public:
  ResourceHashtable() : ResourceHashtableBase<FixedResourceHashtableStorage<SIZE, K, V>,
                                              K, V, ALLOC_TYPE, MEM_TYPE, HASH, EQUALS>() {}
};

#endif // SHARE_UTILITIES_RESOURCEHASH_HPP

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