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#ifndef SQL_HSET_INCLUDED
#define SQL_HSET_INCLUDED
/* Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
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; version 2 of the License.
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, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */
#include "my_global.h"
#include "hash.h"
/**
A type-safe wrapper around mysys HASH.
*/
template <typename T>
class Hash_set
{
public:
enum { START_SIZE= 8 };
/**
Constructs an empty unique hash.
*/
Hash_set(PSI_memory_key psi_key,
const uchar *(*K)(const void *, size_t *, my_bool),
CHARSET_INFO *cs= &my_charset_bin)
{
my_hash_init(psi_key, &m_hash, cs, START_SIZE, 0, 0, K, 0, HASH_UNIQUE);
}
Hash_set(PSI_memory_key psi_key, CHARSET_INFO *charset, ulong default_array_elements,
size_t key_offset, size_t key_length, my_hash_get_key get_key,
void (*free_element)(void*), uint flags)
{
my_hash_init(psi_key, &m_hash, charset, default_array_elements, key_offset,
key_length, get_key, free_element, flags);
}
/**
Destroy the hash by freeing the buckets table. Does
not call destructors for the elements.
*/
~Hash_set()
{
my_hash_free(&m_hash);
}
/**
Insert a single value into a hash. Does not tell whether
the value was inserted -- if an identical value existed,
it is not replaced.
@retval TRUE Out of memory.
@retval FALSE OK. The value either was inserted or existed
in the hash.
*/
bool insert(const T *value)
{
return my_hash_insert(&m_hash, reinterpret_cast<const uchar*>(value));
}
bool remove(const T *value)
{
return my_hash_delete(&m_hash,
reinterpret_cast<uchar*>(const_cast<T*>(value)));
}
T *find(const void *key, size_t klen) const
{
return (T*)my_hash_search(&m_hash, reinterpret_cast<const uchar *>(key), klen);
}
T *find(const T *other) const
{
DBUG_ASSERT(m_hash.get_key);
size_t klen;
const uchar *key= m_hash.get_key(reinterpret_cast<const uchar *>(other),
&klen, false);
return find(key, klen);
}
/** Is this hash set empty? */
bool is_empty() const { return m_hash.records == 0; }
/** Returns the number of unique elements. */
size_t size() const { return static_cast<size_t>(m_hash.records); }
/** Erases all elements from the container */
void clear() { my_hash_reset(&m_hash); }
const T* at(size_t i) const
{
return reinterpret_cast<T*>(my_hash_element(const_cast<HASH*>(&m_hash), i));
}
/** An iterator over hash elements. Is not insert-stable. */
class Iterator;
using value_type= T;
using iterator= Iterator;
using const_iterator= const Iterator;
Iterator begin() const { return Iterator(*this, 0); }
Iterator end() const { return Iterator(*this, m_hash.records); }
class Iterator
{
public:
using iterator_category= std::forward_iterator_tag;
using value_type= T;
using difference_type= std::ptrdiff_t;
using pointer= T *;
using reference= T &;
Iterator(const Hash_set &hash_set, uint idx=0) :
m_hash(&hash_set.m_hash), m_idx(idx) {}
Iterator &operator++()
{
DBUG_ASSERT(m_idx < m_hash->records);
m_idx++;
return *this;
}
T &operator*()
{
return *reinterpret_cast<T *>(my_hash_element(m_hash, m_idx));
}
T *operator->()
{
return reinterpret_cast<T *>(my_hash_element(m_hash, m_idx));
}
bool operator==(const typename Hash_set<T>::iterator &rhs)
{
return m_idx == rhs.m_idx && m_hash == rhs.m_hash;
}
bool operator!=(const typename Hash_set<T>::iterator &rhs)
{
return m_idx != rhs.m_idx || m_hash != rhs.m_hash;
}
private:
const HASH *m_hash;
uint m_idx;
};
private:
HASH m_hash;
};
#endif // SQL_HSET_INCLUDED
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