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Diffstat (limited to 'storage/tokudb/PerconaFT/ft/comparator.h')
| -rw-r--r-- | storage/tokudb/PerconaFT/ft/comparator.h | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/storage/tokudb/PerconaFT/ft/comparator.h b/storage/tokudb/PerconaFT/ft/comparator.h new file mode 100644 index 00000000..dfafd715 --- /dev/null +++ b/storage/tokudb/PerconaFT/ft/comparator.h @@ -0,0 +1,150 @@ +/* -*- mode: C; c-basic-offset: 4; indent-tabs-mode: nil -*- */ +// vim: ft=cpp:expandtab:ts=8:sw=4:softtabstop=4: +/*====== +This file is part of PerconaFT. + + +Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved. + + PerconaFT is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License, version 2, + as published by the Free Software Foundation. + + PerconaFT 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 PerconaFT. If not, see <http://www.gnu.org/licenses/>. + +---------------------------------------- + + PerconaFT is free software: you can redistribute it and/or modify + it under the terms of the GNU Affero General Public License, version 3, + as published by the Free Software Foundation. + + PerconaFT 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 Affero General Public License for more details. + + You should have received a copy of the GNU Affero General Public License + along with PerconaFT. If not, see <http://www.gnu.org/licenses/>. + +---------------------------------------- + + Licensed under the Apache License, Version 2.0 (the "License"); + you may not use this file except in compliance with the License. + You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. +======= */ + +#ident "Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved." + +#pragma once + +#include <db.h> +#include <string.h> + +#include "portability/memory.h" + +#include "util/dbt.h" + +typedef int (*ft_compare_func)(DB *db, const DBT *a, const DBT *b); + +int toku_keycompare(const void *key1, uint32_t key1len, const void *key2, uint32_t key2len); + +int toku_builtin_compare_fun (DB *, const DBT *, const DBT*) __attribute__((__visibility__("default"))); + +namespace toku { + + // a comparator object encapsulates the data necessary for + // comparing two keys in a fractal tree. it further understands + // that points may be positive or negative infinity. + + class comparator { + void init(ft_compare_func cmp, DESCRIPTOR desc, uint8_t memcmp_magic) { + _cmp = cmp; + _fake_db->cmp_descriptor = desc; + _memcmp_magic = memcmp_magic; + } + + public: + // This magic value is reserved to mean that the magic has not been set. + static const uint8_t MEMCMP_MAGIC_NONE = 0; + + void create(ft_compare_func cmp, DESCRIPTOR desc, uint8_t memcmp_magic = MEMCMP_MAGIC_NONE) { + XCALLOC(_fake_db); + init(cmp, desc, memcmp_magic); + } + + // inherit the attributes of another comparator, but keep our own + // copy of fake_db that is owned separately from the one given. + void inherit(const comparator &cmp) { + invariant_notnull(_fake_db); + invariant_notnull(cmp._cmp); + invariant_notnull(cmp._fake_db); + init(cmp._cmp, cmp._fake_db->cmp_descriptor, cmp._memcmp_magic); + } + + // like inherit, but doesn't require that the this comparator + // was already created + void create_from(const comparator &cmp) { + XCALLOC(_fake_db); + inherit(cmp); + } + + void destroy() { + toku_free(_fake_db); + } + + const DESCRIPTOR_S *get_descriptor() const { + return _fake_db->cmp_descriptor; + } + + ft_compare_func get_compare_func() const { + return _cmp; + } + + uint8_t get_memcmp_magic() const { + return _memcmp_magic; + } + + bool valid() const { + return _cmp != nullptr; + } + + inline bool dbt_has_memcmp_magic(const DBT *dbt) const { + return *reinterpret_cast<const char *>(dbt->data) == _memcmp_magic; + } + + int operator()(const DBT *a, const DBT *b) const { + if (__builtin_expect(toku_dbt_is_infinite(a) || toku_dbt_is_infinite(b), 0)) { + return toku_dbt_infinite_compare(a, b); + } else if (_memcmp_magic != MEMCMP_MAGIC_NONE + // If `a' has the memcmp magic.. + && dbt_has_memcmp_magic(a) + // ..then we expect `b' to also have the memcmp magic + && __builtin_expect(dbt_has_memcmp_magic(b), 1)) { + return toku_builtin_compare_fun(nullptr, a, b); + } else { + // yikes, const sadness here + return _cmp(const_cast<DB *>(_fake_db), a, b); + } + } + + private: + DB *_fake_db; + ft_compare_func _cmp; + uint8_t _memcmp_magic; + }; + +} /* namespace toku */ |