pointer_hash.h

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#ifndef POINTER_HASH_CLASS
#define POINTER_HASH_CLASS
 
/*****************************************************************************\
*                                                                             *
*  Name   : pointer_hash                                                      *
*  Author : Chris Koeritz                                                     *
*                                                                             *
*******************************************************************************
* Copyright (c) 2001-$now By Author.  This program is free software; you can  *
* redistribute it and/or modify it under the terms of the GNU General Public  *
* License as published by the Free Software Foundation; either version 2 of   *
* the License or (at your option) any later version.  This is online at:      *
*     http://www.fsf.org/copyleft/gpl.html                                    *
* Please send any updates to: fred@gruntose.com                               *
\*****************************************************************************/
 
#include "byte_hasher.h"
#include "hash_table.h"
#include "pointer_hash.h"
#include "set.h"
 
// forward.
class pointer_set;
 
namespace structures {
 
 
template <class contents>
class pointer_hash : public hash_table<void *, contents>
{
public:
  pointer_hash(int estimated_elements);
  ~pointer_hash();
 
  const pointer_set &ids() const;
  void ids(pointer_set &ids) const;
 
  basis::outcome add(void *key, contents *to_store);
  contents *acquire(void *key);
  bool zap(void *key);
  void reset();
 
  typedef bool apply_function(const void * &key, contents &current,
        void *data_link);
 
  void apply(apply_function *to_apply, void *data_link);
 
private:
  pointer_set *_ids;
 
};
 
 
// implementations for larger methods below...
 
template <class contents>
pointer_hash<contents>::pointer_hash(int estimated_elements)
: hash_table<void *, contents>(rotating_byte_hasher(), estimated_elements),
  _ids(new pointer_set)
{}
 
template <class contents>
pointer_hash<contents>::~pointer_hash()
{ WHACK(_ids); }
 
template <class contents>
const pointer_set &pointer_hash<contents>::ids() const { return *_ids; }
 
template <class contents>
void pointer_hash<contents>::ids(pointer_set &ids) const { ids = *_ids; }
 
template <class contents>
basis::outcome pointer_hash<contents>::add(void *key, contents *to_store)
{
  _ids->add(key);
  return hash_table<void *, contents>::add(key, to_store);
}
 
template <class contents>
contents *pointer_hash<contents>::acquire(void *key)
{
  _ids->remove(key);
  return hash_table<void *, contents>::acquire(key);
}
 
template <class contents>
bool pointer_hash<contents>::zap(void *key)
{
  _ids->remove(key);
  return hash_table<void *, contents>::zap(key);
}
 
template <class contents>
void pointer_hash<contents>::reset()
{
  _ids->clear();
  hash_table<void *, contents>::reset();
}
 
template <class contents>
void pointer_hash<contents>::apply(apply_function *to_apply, void *data_link)
{
  for (int i = 0; i < _ids->elements(); i++) {
    void *current = (*_ids)[i];
    contents *found = hash_table<void *, contents>::find(current);
    if (!found) {
      _ids->remove(current);
      continue;
    }
    to_apply(current, *found, data_link);
  }
}
 
} //namespace.
 
#endif // outer guard.