105 lines
2.7 KiB
C++
105 lines
2.7 KiB
C++
// Copyright (C) 2013 Red Hat, Inc. All rights reserved.
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//
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// This file is part of the thin-provisioning-tools source.
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//
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// thin-provisioning-tools is free software: you can redistribute it
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// and/or modify it under the terms of the GNU General Public License
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// as published by the Free Software Foundation, either version 3 of
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// the License, or (at your option) any later version.
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//
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// thin-provisioning-tools is distributed in the hope that it will be
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// useful, but WITHOUT ANY WARRANTY; without even the implied warranty
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// of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License along
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// with thin-provisioning-tools. If not, see
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// <http://www.gnu.org/licenses/>.
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#ifndef BUFFER_H
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#define BUFFER_H
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#include <stdint.h>
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// #include <stdlib.h>
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#include <malloc.h>
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#include <boost/noncopyable.hpp>
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#include <boost/optional.hpp>
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#include <boost/shared_ptr.hpp>
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#include <boost/static_assert.hpp>
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#include <stdexcept>
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//----------------------------------------------------------------
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namespace persistent_data {
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uint32_t const DEFAULT_BUFFER_SIZE = 4096;
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// Allocate buffer of Size with Alignment imposed.
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//
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// Allocation needs to be on the heap in order to provide alignment
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// guarantees.
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//
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// Alignment must be a power of two.
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template <uint32_t Size = DEFAULT_BUFFER_SIZE, uint32_t Alignment = 512>
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class buffer : private boost::noncopyable {
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public:
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BOOST_STATIC_ASSERT_MSG((Alignment > 1) & !(Alignment & (Alignment - 1)),
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"Alignment must be a power of two.");
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static uint32_t const ALIGNMENT = Alignment;
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typedef boost::shared_ptr<buffer> ptr;
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typedef boost::shared_ptr<buffer const> const_ptr;
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unsigned char &operator[](unsigned index) {
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check_index(index);
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return data_[index];
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}
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unsigned char const &operator[](unsigned index) const {
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check_index(index);
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return data_[index];
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}
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unsigned char *raw() {
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return data_;
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}
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unsigned char const *raw() const {
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return data_;
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}
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static void *operator new(size_t s) {
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// void *r;
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// return posix_memalign(&r, Alignment, s) ? NULL : r;
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// Allocates size bytes and returns a pointer to the
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// allocated memory. The memory address will be a
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// multiple of 'Alignment', which must be a power of two
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void *mem = memalign(Alignment, s);
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if (!mem)
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throw std::bad_alloc();
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return mem;
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}
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static void operator delete(void *p) {
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free(p);
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}
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private:
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unsigned char data_[Size];
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static void check_index(unsigned index) {
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if (index >= Size)
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throw std::range_error("buffer index out of bounds");
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}
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};
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}
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//----------------------------------------------------------------
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#endif
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