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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 18:07:14 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 18:07:14 +0000 |
commit | a175314c3e5827eb193872241446f2f8f5c9d33c (patch) | |
tree | cd3d60ca99ae00829c52a6ca79150a5b6e62528b /sql/sql_hset.h | |
parent | Initial commit. (diff) | |
download | mariadb-10.5-9e4947182e0b875da38088fdd168e775f473b8ad.tar.xz mariadb-10.5-9e4947182e0b875da38088fdd168e775f473b8ad.zip |
Adding upstream version 1:10.5.12.upstream/1%10.5.12upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'sql/sql_hset.h')
-rw-r--r-- | sql/sql_hset.h | 117 |
1 files changed, 117 insertions, 0 deletions
diff --git a/sql/sql_hset.h b/sql/sql_hset.h new file mode 100644 index 00000000..b3d8165f --- /dev/null +++ b/sql/sql_hset.h @@ -0,0 +1,117 @@ +#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 "hash.h" + + +/** + A type-safe wrapper around mysys HASH. +*/ + +template <typename T> +class Hash_set +{ +public: + enum { START_SIZE= 8 }; + /** + Constructs an empty hash. Does not allocate memory, it is done upon + the first insert. Thus does not cause or return errors. + */ + Hash_set(PSI_memory_key psi_key, uchar *(*K)(const T *, size_t *, my_bool), + CHARSET_INFO *cs= &my_charset_bin) + { + my_hash_clear(&m_hash); + m_hash.get_key= (my_hash_get_key)K; + m_hash.charset= cs; + m_hash.array.m_psi_key= psi_key; + } + 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(T *value) + { + my_hash_init_opt(m_hash.array.m_psi_key, &m_hash, m_hash.charset, + START_SIZE, 0, 0, m_hash.get_key, 0, HASH_UNIQUE); + return my_hash_insert(&m_hash, reinterpret_cast<const uchar*>(value)); + } + bool remove(T *value) + { + return my_hash_delete(&m_hash, reinterpret_cast<uchar*>(value)); + } + T *find(const void *key, size_t klen) const + { + return (T*)my_hash_search(&m_hash, reinterpret_cast<const uchar *>(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 + { + public: + Iterator(Hash_set &hash_set) + : m_hash(&hash_set.m_hash), + m_idx(0) + {} + /** + Return the current element and reposition the iterator to the next + element. + */ + inline T *operator++(int) + { + if (m_idx < m_hash->records) + return reinterpret_cast<T*>(my_hash_element(m_hash, m_idx++)); + return NULL; + } + void rewind() { m_idx= 0; } + private: + HASH *m_hash; + uint m_idx; + }; +private: + HASH m_hash; +}; + +#endif // SQL_HSET_INCLUDED |