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Unverified Commit 6ab2f0e0 authored by Gabi Melman's avatar Gabi Melman Committed by GitHub
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Merge pull request #548 from Subenle/master 

Declare variables as size_t rather than unsigned.
parents f70b2ef3 34a9f24d
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include/spdlog/details/mpmc_bounded_q.h
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/*
A modified version of Bounded MPMC queue by Dmitry Vyukov.
Original code from:
http://www.1024cores.net/home/lock-free-algorithms/queues/bounded-mpmc-queue
licensed by Dmitry Vyukov under the terms below:
Simplified BSD license
Copyright (c) 2010-2011 Dmitry Vyukov. All rights reserved.
Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice, this list of
conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice, this list
of conditions and the following disclaimer in the documentation and/or other materials
provided with the distribution.
THIS SOFTWARE IS PROVIDED BY DMITRY VYUKOV "AS IS" AND ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
SHALL DMITRY VYUKOV OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
The views and conclusions contained in the software and documentation are those of the authors and
should not be interpreted as representing official policies, either expressed or implied, of Dmitry Vyukov.
*/
/*
The code in its current form adds the license below:
Copyright(c) 2015 Gabi Melman.
Distributed under the MIT License (http://opensource.org/licenses/MIT)
*/
#pragma once
#include "spdlog/common.h"
#include <atomic>
#include <utility>
namespace spdlog
{
namespace details
{
template<typename T>
class mpmc_bounded_queue
{
public:
using item_type = T;
mpmc_bounded_queue(size_t buffer_size)
:max_size_(buffer_size),
buffer_(new cell_t[buffer_size]),
buffer_mask_(buffer_size - 1)
{
//queue size must be power of two
if (!((buffer_size >= 2) && ((buffer_size & (buffer_size - 1)) == 0)))
throw spdlog_ex("async logger queue size must be power of two");
for (size_t i = 0; i != buffer_size; i += 1)
buffer_[i].sequence_.store(i, std::memory_order_relaxed);
enqueue_pos_.store(0, std::memory_order_relaxed);
dequeue_pos_.store(0, std::memory_order_relaxed);
}
~mpmc_bounded_queue()
{
delete[] buffer_;
}
bool enqueue(T&& data)
{
cell_t* cell;
size_t pos = enqueue_pos_.load(std::memory_order_relaxed);
for (;;) {
cell = &buffer_[pos & buffer_mask_];
size_t seq = cell->sequence_.load(std::memory_order_acquire);
intptr_t dif = static_cast<intptr_t>(seq) - static_cast<intptr_t>(pos);
if (dif == 0) {
if (enqueue_pos_.compare_exchange_weak(pos, pos + 1, std::memory_order_relaxed))
break;
}
else if (dif < 0) {
return false;
}
else {
pos = enqueue_pos_.load(std::memory_order_relaxed);
}
}
cell->data_ = std::move(data);
cell->sequence_.store(pos + 1, std::memory_order_release);
return true;
}
bool dequeue(T& data)
{
cell_t* cell;
size_t pos = dequeue_pos_.load(std::memory_order_relaxed);
for (;;) {
cell = &buffer_[pos & buffer_mask_];
size_t seq =
cell->sequence_.load(std::memory_order_acquire);
intptr_t dif = static_cast<intptr_t>(seq) - static_cast<intptr_t>(pos + 1);
if (dif == 0) {
if (dequeue_pos_.compare_exchange_weak(pos, pos + 1, std::memory_order_relaxed))
break;
}
else if (dif < 0)
return false;
else
pos = dequeue_pos_.load(std::memory_order_relaxed);
}
data = std::move(cell->data_);
cell->sequence_.store(pos + buffer_mask_ + 1, std::memory_order_release);
return true;
}
bool is_empty()
{
unsigned front, front1, back;
// try to take a consistent snapshot of front/tail.
/*
A modified version of Bounded MPMC queue by Dmitry Vyukov.
Original code from:
http://www.1024cores.net/home/lock-free-algorithms/queues/bounded-mpmc-queue
licensed by Dmitry Vyukov under the terms below:
Simplified BSD license
Copyright (c) 2010-2011 Dmitry Vyukov. All rights reserved.
Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice, this list of
conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice, this list
of conditions and the following disclaimer in the documentation and/or other materials
provided with the distribution.
THIS SOFTWARE IS PROVIDED BY DMITRY VYUKOV "AS IS" AND ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
SHALL DMITRY VYUKOV OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
The views and conclusions contained in the software and documentation are those of the authors and
should not be interpreted as representing official policies, either expressed or implied, of Dmitry Vyukov.
*/
/*
The code in its current form adds the license below:
Copyright(c) 2015 Gabi Melman.
Distributed under the MIT License (http://opensource.org/licenses/MIT)
*/
#pragma once
#include "spdlog/common.h"
#include <atomic>
#include <utility>
namespace spdlog
{
namespace details
{
template<typename T>
class mpmc_bounded_queue
{
public:
using item_type = T;
mpmc_bounded_queue(size_t buffer_size)
:max_size_(buffer_size),
buffer_(new cell_t[buffer_size]),
buffer_mask_(buffer_size - 1)
{
//queue size must be power of two
if (!((buffer_size >= 2) && ((buffer_size & (buffer_size - 1)) == 0)))
throw spdlog_ex("async logger queue size must be power of two");
for (size_t i = 0; i != buffer_size; i += 1)
buffer_[i].sequence_.store(i, std::memory_order_relaxed);
enqueue_pos_.store(0, std::memory_order_relaxed);
dequeue_pos_.store(0, std::memory_order_relaxed);
}
~mpmc_bounded_queue()
{
delete[] buffer_;
}
bool enqueue(T&& data)
{
cell_t* cell;
size_t pos = enqueue_pos_.load(std::memory_order_relaxed);
for (;;) {
cell = &buffer_[pos & buffer_mask_];
size_t seq = cell->sequence_.load(std::memory_order_acquire);
intptr_t dif = static_cast<intptr_t>(seq) - static_cast<intptr_t>(pos);
if (dif == 0) {
if (enqueue_pos_.compare_exchange_weak(pos, pos + 1, std::memory_order_relaxed))
break;
}
else if (dif < 0) {
return false;
}
else {
pos = enqueue_pos_.load(std::memory_order_relaxed);
}
}
cell->data_ = std::move(data);
cell->sequence_.store(pos + 1, std::memory_order_release);
return true;
}
bool dequeue(T& data)
{
cell_t* cell;
size_t pos = dequeue_pos_.load(std::memory_order_relaxed);
for (;;) {
cell = &buffer_[pos & buffer_mask_];
size_t seq =
cell->sequence_.load(std::memory_order_acquire);
intptr_t dif = static_cast<intptr_t>(seq) - static_cast<intptr_t>(pos + 1);
if (dif == 0) {
if (dequeue_pos_.compare_exchange_weak(pos, pos + 1, std::memory_order_relaxed))
break;
}
else if (dif < 0)
return false;
else
pos = dequeue_pos_.load(std::memory_order_relaxed);
}
data = std::move(cell->data_);
cell->sequence_.store(pos + buffer_mask_ + 1, std::memory_order_release);
return true;
}
bool is_empty()
{
size_t front, front1, back;
// try to take a consistent snapshot of front/tail.
do {
front = enqueue_pos_.load(std::memory_order_acquire);
back = dequeue_pos_.load(std::memory_order_acquire);
front1 = enqueue_pos_.load(std::memory_order_relaxed);
} while (front != front1);
return back == front;
}
private:
struct cell_t
{
std::atomic<size_t> sequence_;
T data_;
};
size_t const max_size_;
static size_t const cacheline_size = 64;
typedef char cacheline_pad_t[cacheline_size];
cacheline_pad_t pad0_;
cell_t* const buffer_;
size_t const buffer_mask_;
cacheline_pad_t pad1_;
std::atomic<size_t> enqueue_pos_;
cacheline_pad_t pad2_;
std::atomic<size_t> dequeue_pos_;
cacheline_pad_t pad3_;
mpmc_bounded_queue(mpmc_bounded_queue const&) = delete;
void operator= (mpmc_bounded_queue const&) = delete;
};
} // ns details
} // ns spdlog
front1 = enqueue_pos_.load(std::memory_order_relaxed);
} while (front != front1);
return back == front;
}
private:
struct cell_t
{
std::atomic<size_t> sequence_;
T data_;
};
size_t const max_size_;
static size_t const cacheline_size = 64;
typedef char cacheline_pad_t[cacheline_size];
cacheline_pad_t pad0_;
cell_t* const buffer_;
size_t const buffer_mask_;
cacheline_pad_t pad1_;
std::atomic<size_t> enqueue_pos_;
cacheline_pad_t pad2_;
std::atomic<size_t> dequeue_pos_;
cacheline_pad_t pad3_;
mpmc_bounded_queue(mpmc_bounded_queue const&) = delete;
void operator= (mpmc_bounded_queue const&) = delete;
};
} // ns details
} // ns spdlog
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