#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