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90 lines
2.4 KiB
C++
90 lines
2.4 KiB
C++
#ifndef SQL_TREE_INCLUDED
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#define SQL_TREE_INCLUDED
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/*
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Copyright (c) 2026, MariaDB plc
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA
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*/
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#include <my_tree.h>
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/*
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Type-safe wrapper around the C TREE red-black tree.
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*/
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template<typename T, typename Param=void>
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class Tree
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{
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TREE m_tree;
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static int free_shim(void *elem, TREE_FREE action, void *)
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{
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if (action == free_free)
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static_cast<T *>(elem)->~T();
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return 0;
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}
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template<typename Ctx>
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struct walk_arg
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{
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int (*fn)(const T &, element_count, Ctx *);
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Ctx *ctx;
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};
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template<typename Ctx>
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static int call_shim(void *elem, element_count cnt, void *arg_)
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{
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auto *arg= static_cast<walk_arg<Ctx> *>(arg_);
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return arg->fn(*static_cast<const T *>(elem), cnt, arg->ctx);
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}
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public:
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explicit Tree(qsort_cmp2 fn, Param *extra_arg= nullptr, myf flags= MYF(0))
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{
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init_tree(&m_tree, 0, 0, sizeof(T), fn, free_shim, (void*)extra_arg, flags);
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}
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~Tree() { delete_tree(&m_tree, 0); }
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void clear() { delete_tree(&m_tree, 0); }
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Tree(const Tree &)= delete;
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Tree &operator=(const Tree &)= delete;
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/* Insert val; returns true on OOM. Duplicate inserts increment the count. */
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bool insert(const T &val)
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{
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return tree_insert(&m_tree, &val, 0, m_tree.custom_arg) == nullptr;
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}
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T *find(const T &key)
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{
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return static_cast<T *>(tree_search(&m_tree, &key, m_tree.custom_arg));
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}
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/*
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Walk all elements in order, calling fn(const T &, element_count, Ctx &).
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fn should return 0 to continue, non-zero to stop.
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*/
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template<typename Ctx>
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int walk(int (*fn)(const T &, element_count, Ctx *), Ctx *ctx,
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TREE_WALK dir= left_root_right)
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{
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walk_arg<Ctx> arg= {fn, ctx};
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return tree_walk(&m_tree, call_shim<Ctx>, &arg, dir);
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}
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uint elements() const { return m_tree.elements_in_tree; }
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};
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#endif /* SQL_TREE_INCLUDED */
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