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118 lines
3.3 KiB
C++
118 lines
3.3 KiB
C++
/* -*- mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- */
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#ident "$Id$"
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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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#ident "Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved."
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#include <algorithm>
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#include <cassert>
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#include <cstdlib>
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#include <memory>
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#include "buffer.hpp"
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namespace ftcxx {
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const size_t Buffer::INITIAL_CAPACITY = 1<<10;
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const size_t Buffer::MAXIMUM_CAPACITY = 1<<18;
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const double Buffer::FULLNESS_RATIO = 0.9;
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Buffer::Buffer()
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: _cur(0),
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_end(0),
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_capacity(INITIAL_CAPACITY),
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_buf(nullptr, &std::free)
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{
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init();
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}
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Buffer::Buffer(size_t capacity)
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: _end(0),
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_capacity(capacity),
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_buf(nullptr, &std::free)
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{
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init();
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}
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char *Buffer::alloc(size_t sz) {
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grow(sz);
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char *p = raw(_end);
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_end += sz;
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return p;
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}
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bool Buffer::full() const {
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return _end > MAXIMUM_CAPACITY * FULLNESS_RATIO;
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}
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bool Buffer::more() const {
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return _cur < _end;
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}
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char *Buffer::current() const {
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return raw(_cur);
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}
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void Buffer::advance(size_t sz) {
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_cur += sz;
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}
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void Buffer::clear() {
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_cur = 0;
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_end = 0;
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}
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void Buffer::init() {
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_buf.reset(static_cast<char *>(std::malloc(_capacity)));
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}
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size_t Buffer::next_alloc_size(size_t sz) {
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return sz * 2;
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}
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void Buffer::grow(size_t sz) {
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size_t new_capacity = _capacity;
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while (new_capacity < _end + sz) {
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new_capacity = next_alloc_size(new_capacity);
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}
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assert(new_capacity >= _capacity); // overflow?
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if (new_capacity > _capacity) {
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std::unique_ptr<char, void (*)(void *)> new_buf(static_cast<char *>(std::malloc(new_capacity)), &std::free);
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std::copy(raw(0), raw(_end), &new_buf.get()[0]);
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std::swap(_buf, new_buf);
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_capacity = new_capacity;
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}
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}
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} // namespace ftcxx
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