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/* Copyright (C) 2021 Free Software Foundation, Inc.
Contributed by Oracle.
This file is part of GNU Binutils.
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 3, or (at your option)
any later version.
This program 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 for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, 51 Franklin Street - Fifth Floor, Boston,
MA 02110-1301, USA. */
/*
* Dbe Cache Map implementation.
*
* Simple Cache Map makes the following assumptions:
* - Cache Map is used for very fast but not guaranteed mapping;
* - No Relations can be used;
* - all objects used as keys or values has to be managed
* outside CacheMap (f.e. deletion);
*/
#ifndef _DbeCacheMap_h
#define _DbeCacheMap_h
#include <Map.h>
template <typename Key_t, class ITEM>
class DbeCacheMap : public Map<Key_t, ITEM *>
{
public:
DbeCacheMap (int _size = DefaultSize)
{ // _size should be 2 ** N
size = _size;
table = new DbeCache_T[size];
memset (table, 0, size * sizeof (DbeCache_T));
};
~DbeCacheMap ()
{
delete[] table;
};
void
put (Key_t key, ITEM *val)
{
int ind = get_hash (key);
table[ind].key = key;
table[ind].value = val;
};
ITEM *
get (Key_t key)
{
int ind = get_hash (key);
if (table[ind].key == key)
return table[ind].value;
return (ITEM *) NULL;
};
ITEM *
remove (Key_t key)
{
int ind = get_hash (key);
ITEM *v = table[ind].value;
table[ind].value = (ITEM *) NULL;
return v;
};
ITEM *
get (Key_t /* key */, typename Map<Key_t, ITEM *>::Relation /* rel */)
{
return (ITEM *) NULL;
};
private:
enum
{
DefaultSize = (1 << 13)
};
typedef struct DbeCache_S
{
Key_t key;
ITEM *value;
} DbeCache_T;
DbeCache_T *table;
int size;
int
get_hash (Key_t key)
{
unsigned long long h = (unsigned long long) key;
h ^= (h >> 20) ^ (h >> 12);
return (h ^ (h >> 7) ^ (h >> 4)) & (size - 1);
}
};
#endif
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