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138 lines
4.6 KiB
138 lines
4.6 KiB
/* -*- mode: C; c-basic-offset: 4; indent-tabs-mode: nil -*- */
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// vim: ft=cpp:expandtab:ts=8:sw=4:softtabstop=4:
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/*======
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This file is part of PerconaFT.
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Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved.
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PerconaFT is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License, version 2,
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as published by the Free Software Foundation.
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PerconaFT 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 PerconaFT. If not, see <http://www.gnu.org/licenses/>.
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----------------------------------------
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PerconaFT is free software: you can redistribute it and/or modify
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it under the terms of the GNU Affero General Public License, version 3,
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as published by the Free Software Foundation.
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PerconaFT 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 Affero General Public License for more details.
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You should have received a copy of the GNU Affero General Public License
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along with PerconaFT. If not, see <http://www.gnu.org/licenses/>.
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----------------------------------------
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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======= */
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#ident \
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"Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved."
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#pragma once
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#include <string.h>
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#include "../db.h"
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#include "../portability/memory.h"
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#include "../util/dbt.h"
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typedef int (*ft_compare_func)(void *arg, const DBT *a, const DBT *b);
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int toku_keycompare(const void *key1, size_t key1len, const void *key2,
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size_t key2len);
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int toku_builtin_compare_fun(const DBT *, const DBT *)
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__attribute__((__visibility__("default")));
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namespace toku {
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// a comparator object encapsulates the data necessary for
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// comparing two keys in a fractal tree. it further understands
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// that points may be positive or negative infinity.
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class comparator {
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void init(ft_compare_func cmp, void *cmp_arg, uint8_t memcmp_magic) {
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_cmp = cmp;
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_cmp_arg = cmp_arg;
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_memcmp_magic = memcmp_magic;
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}
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public:
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// This magic value is reserved to mean that the magic has not been set.
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static const uint8_t MEMCMP_MAGIC_NONE = 0;
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void create(ft_compare_func cmp, void *cmp_arg,
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uint8_t memcmp_magic = MEMCMP_MAGIC_NONE) {
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init(cmp, cmp_arg, memcmp_magic);
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}
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// inherit the attributes of another comparator, but keep our own
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// copy of fake_db that is owned separately from the one given.
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void inherit(const comparator &cmp) {
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invariant_notnull(cmp._cmp);
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init(cmp._cmp, cmp._cmp_arg, cmp._memcmp_magic);
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}
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// like inherit, but doesn't require that the this comparator
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// was already created
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void create_from(const comparator &cmp) { inherit(cmp); }
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void destroy() {}
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ft_compare_func get_compare_func() const { return _cmp; }
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uint8_t get_memcmp_magic() const { return _memcmp_magic; }
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bool valid() const { return _cmp != nullptr; }
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inline bool dbt_has_memcmp_magic(const DBT *dbt) const {
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return *reinterpret_cast<const char *>(dbt->data) == _memcmp_magic;
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}
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int operator()(const DBT *a, const DBT *b) const {
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if (__builtin_expect(toku_dbt_is_infinite(a) || toku_dbt_is_infinite(b),
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0)) {
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return toku_dbt_infinite_compare(a, b);
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} else if (_memcmp_magic != MEMCMP_MAGIC_NONE
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// If `a' has the memcmp magic..
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&& dbt_has_memcmp_magic(a)
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// ..then we expect `b' to also have the memcmp magic
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&& __builtin_expect(dbt_has_memcmp_magic(b), 1)) {
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assert(0); // psergey: this branch should not be taken.
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return toku_builtin_compare_fun(a, b);
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} else {
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// yikes, const sadness here
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return _cmp(_cmp_arg, a, b);
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}
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}
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private:
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ft_compare_func _cmp;
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void *_cmp_arg;
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uint8_t _memcmp_magic;
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};
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} /* namespace toku */
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