1002 lines
31 KiB
C++
1002 lines
31 KiB
C++
// lock-free single-producer/single-consumer ringbuffer
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// this algorithm is implemented in various projects (linux kernel)
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//
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// Copyright (C) 2009-2013 Tim Blechmann
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//
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// Distributed under the Boost Software License, Version 1.0. (See
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// accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_LOCKFREE_SPSC_QUEUE_HPP_INCLUDED
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#define BOOST_LOCKFREE_SPSC_QUEUE_HPP_INCLUDED
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#include <algorithm>
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#include <memory>
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#include <boost/aligned_storage.hpp>
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#include <boost/assert.hpp>
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#include <boost/static_assert.hpp>
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#include <boost/utility.hpp>
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#include <boost/utility/enable_if.hpp>
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#include <boost/config.hpp> // for BOOST_LIKELY
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#include <boost/type_traits/has_trivial_destructor.hpp>
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#include <boost/type_traits/is_convertible.hpp>
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#include <boost/lockfree/detail/atomic.hpp>
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#include <boost/lockfree/detail/copy_payload.hpp>
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#include <boost/lockfree/detail/parameter.hpp>
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#include <boost/lockfree/detail/prefix.hpp>
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#include <boost/lockfree/lockfree_forward.hpp>
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#ifdef BOOST_HAS_PRAGMA_ONCE
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#pragma once
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#endif
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namespace boost {
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namespace lockfree {
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namespace detail {
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typedef parameter::parameters<boost::parameter::optional<tag::capacity>,
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boost::parameter::optional<tag::allocator>
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> ringbuffer_signature;
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template <typename T>
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class ringbuffer_base
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{
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#ifndef BOOST_DOXYGEN_INVOKED
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protected:
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typedef std::size_t size_t;
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static const int padding_size = BOOST_LOCKFREE_CACHELINE_BYTES - sizeof(size_t);
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atomic<size_t> write_index_;
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char padding1[padding_size]; /* force read_index and write_index to different cache lines */
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atomic<size_t> read_index_;
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BOOST_DELETED_FUNCTION(ringbuffer_base(ringbuffer_base const&))
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BOOST_DELETED_FUNCTION(ringbuffer_base& operator= (ringbuffer_base const&))
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protected:
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ringbuffer_base(void):
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write_index_(0), read_index_(0)
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{}
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static size_t next_index(size_t arg, size_t max_size)
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{
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size_t ret = arg + 1;
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while (BOOST_UNLIKELY(ret >= max_size))
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ret -= max_size;
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return ret;
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}
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static size_t read_available(size_t write_index, size_t read_index, size_t max_size)
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{
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if (write_index >= read_index)
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return write_index - read_index;
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const size_t ret = write_index + max_size - read_index;
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return ret;
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}
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static size_t write_available(size_t write_index, size_t read_index, size_t max_size)
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{
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size_t ret = read_index - write_index - 1;
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if (write_index >= read_index)
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ret += max_size;
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return ret;
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}
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size_t read_available(size_t max_size) const
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{
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size_t write_index = write_index_.load(memory_order_acquire);
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const size_t read_index = read_index_.load(memory_order_relaxed);
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return read_available(write_index, read_index, max_size);
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}
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size_t write_available(size_t max_size) const
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{
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size_t write_index = write_index_.load(memory_order_relaxed);
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const size_t read_index = read_index_.load(memory_order_acquire);
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return write_available(write_index, read_index, max_size);
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}
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bool push(T const & t, T * buffer, size_t max_size)
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{
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const size_t write_index = write_index_.load(memory_order_relaxed); // only written from push thread
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const size_t next = next_index(write_index, max_size);
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if (next == read_index_.load(memory_order_acquire))
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return false; /* ringbuffer is full */
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new (buffer + write_index) T(t); // copy-construct
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write_index_.store(next, memory_order_release);
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return true;
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}
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size_t push(const T * input_buffer, size_t input_count, T * internal_buffer, size_t max_size)
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{
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return push(input_buffer, input_buffer + input_count, internal_buffer, max_size) - input_buffer;
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}
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template <typename ConstIterator>
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ConstIterator push(ConstIterator begin, ConstIterator end, T * internal_buffer, size_t max_size)
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{
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// FIXME: avoid std::distance
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const size_t write_index = write_index_.load(memory_order_relaxed); // only written from push thread
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const size_t read_index = read_index_.load(memory_order_acquire);
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const size_t avail = write_available(write_index, read_index, max_size);
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if (avail == 0)
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return begin;
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size_t input_count = std::distance(begin, end);
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input_count = (std::min)(input_count, avail);
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size_t new_write_index = write_index + input_count;
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const ConstIterator last = boost::next(begin, input_count);
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if (write_index + input_count > max_size) {
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/* copy data in two sections */
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const size_t count0 = max_size - write_index;
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const ConstIterator midpoint = boost::next(begin, count0);
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std::uninitialized_copy(begin, midpoint, internal_buffer + write_index);
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std::uninitialized_copy(midpoint, last, internal_buffer);
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new_write_index -= max_size;
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} else {
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std::uninitialized_copy(begin, last, internal_buffer + write_index);
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if (new_write_index == max_size)
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new_write_index = 0;
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}
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write_index_.store(new_write_index, memory_order_release);
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return last;
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}
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template <typename Functor>
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bool consume_one(Functor & functor, T * buffer, size_t max_size)
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{
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const size_t write_index = write_index_.load(memory_order_acquire);
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const size_t read_index = read_index_.load(memory_order_relaxed); // only written from pop thread
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if ( empty(write_index, read_index) )
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return false;
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T & object_to_consume = buffer[read_index];
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functor( object_to_consume );
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object_to_consume.~T();
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size_t next = next_index(read_index, max_size);
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read_index_.store(next, memory_order_release);
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return true;
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}
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template <typename Functor>
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bool consume_one(Functor const & functor, T * buffer, size_t max_size)
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{
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const size_t write_index = write_index_.load(memory_order_acquire);
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const size_t read_index = read_index_.load(memory_order_relaxed); // only written from pop thread
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if ( empty(write_index, read_index) )
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return false;
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T & object_to_consume = buffer[read_index];
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functor( object_to_consume );
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object_to_consume.~T();
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size_t next = next_index(read_index, max_size);
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read_index_.store(next, memory_order_release);
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return true;
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}
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template <typename Functor>
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size_t consume_all (Functor const & functor, T * internal_buffer, size_t max_size)
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{
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const size_t write_index = write_index_.load(memory_order_acquire);
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const size_t read_index = read_index_.load(memory_order_relaxed); // only written from pop thread
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const size_t avail = read_available(write_index, read_index, max_size);
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if (avail == 0)
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return 0;
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const size_t output_count = avail;
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size_t new_read_index = read_index + output_count;
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if (read_index + output_count > max_size) {
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/* copy data in two sections */
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const size_t count0 = max_size - read_index;
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const size_t count1 = output_count - count0;
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run_functor_and_delete(internal_buffer + read_index, internal_buffer + max_size, functor);
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run_functor_and_delete(internal_buffer, internal_buffer + count1, functor);
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new_read_index -= max_size;
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} else {
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run_functor_and_delete(internal_buffer + read_index, internal_buffer + read_index + output_count, functor);
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if (new_read_index == max_size)
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new_read_index = 0;
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}
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read_index_.store(new_read_index, memory_order_release);
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return output_count;
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}
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template <typename Functor>
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size_t consume_all (Functor & functor, T * internal_buffer, size_t max_size)
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{
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const size_t write_index = write_index_.load(memory_order_acquire);
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const size_t read_index = read_index_.load(memory_order_relaxed); // only written from pop thread
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const size_t avail = read_available(write_index, read_index, max_size);
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if (avail == 0)
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return 0;
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const size_t output_count = avail;
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size_t new_read_index = read_index + output_count;
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if (read_index + output_count > max_size) {
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/* copy data in two sections */
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const size_t count0 = max_size - read_index;
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const size_t count1 = output_count - count0;
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run_functor_and_delete(internal_buffer + read_index, internal_buffer + max_size, functor);
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run_functor_and_delete(internal_buffer, internal_buffer + count1, functor);
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new_read_index -= max_size;
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} else {
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run_functor_and_delete(internal_buffer + read_index, internal_buffer + read_index + output_count, functor);
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if (new_read_index == max_size)
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new_read_index = 0;
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}
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read_index_.store(new_read_index, memory_order_release);
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return output_count;
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}
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size_t pop (T * output_buffer, size_t output_count, T * internal_buffer, size_t max_size)
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{
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const size_t write_index = write_index_.load(memory_order_acquire);
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const size_t read_index = read_index_.load(memory_order_relaxed); // only written from pop thread
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const size_t avail = read_available(write_index, read_index, max_size);
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if (avail == 0)
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return 0;
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output_count = (std::min)(output_count, avail);
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size_t new_read_index = read_index + output_count;
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if (read_index + output_count > max_size) {
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/* copy data in two sections */
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const size_t count0 = max_size - read_index;
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const size_t count1 = output_count - count0;
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copy_and_delete(internal_buffer + read_index, internal_buffer + max_size, output_buffer);
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copy_and_delete(internal_buffer, internal_buffer + count1, output_buffer + count0);
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new_read_index -= max_size;
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} else {
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copy_and_delete(internal_buffer + read_index, internal_buffer + read_index + output_count, output_buffer);
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if (new_read_index == max_size)
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new_read_index = 0;
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}
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read_index_.store(new_read_index, memory_order_release);
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return output_count;
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}
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template <typename OutputIterator>
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size_t pop_to_output_iterator (OutputIterator it, T * internal_buffer, size_t max_size)
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{
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const size_t write_index = write_index_.load(memory_order_acquire);
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const size_t read_index = read_index_.load(memory_order_relaxed); // only written from pop thread
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const size_t avail = read_available(write_index, read_index, max_size);
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if (avail == 0)
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return 0;
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size_t new_read_index = read_index + avail;
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if (read_index + avail > max_size) {
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/* copy data in two sections */
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const size_t count0 = max_size - read_index;
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const size_t count1 = avail - count0;
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it = copy_and_delete(internal_buffer + read_index, internal_buffer + max_size, it);
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copy_and_delete(internal_buffer, internal_buffer + count1, it);
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new_read_index -= max_size;
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} else {
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copy_and_delete(internal_buffer + read_index, internal_buffer + read_index + avail, it);
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if (new_read_index == max_size)
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new_read_index = 0;
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}
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read_index_.store(new_read_index, memory_order_release);
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return avail;
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}
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const T& front(const T * internal_buffer) const
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{
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const size_t read_index = read_index_.load(memory_order_relaxed); // only written from pop thread
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return *(internal_buffer + read_index);
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}
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T& front(T * internal_buffer)
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{
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const size_t read_index = read_index_.load(memory_order_relaxed); // only written from pop thread
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return *(internal_buffer + read_index);
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}
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#endif
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public:
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/** reset the ringbuffer
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*
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* \note Not thread-safe
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* */
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void reset(void)
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{
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if ( !boost::has_trivial_destructor<T>::value ) {
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// make sure to call all destructors!
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T dummy_element;
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while (pop(dummy_element))
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{}
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} else {
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write_index_.store(0, memory_order_relaxed);
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read_index_.store(0, memory_order_release);
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}
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}
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/** Check if the ringbuffer is empty
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*
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* \return true, if the ringbuffer is empty, false otherwise
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* \note Due to the concurrent nature of the ringbuffer the result may be inaccurate.
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* */
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bool empty(void)
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{
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return empty(write_index_.load(memory_order_relaxed), read_index_.load(memory_order_relaxed));
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}
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/**
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* \return true, if implementation is lock-free.
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*
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* */
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bool is_lock_free(void) const
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{
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return write_index_.is_lock_free() && read_index_.is_lock_free();
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}
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private:
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bool empty(size_t write_index, size_t read_index)
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{
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return write_index == read_index;
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}
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template< class OutputIterator >
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OutputIterator copy_and_delete( T * first, T * last, OutputIterator out )
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{
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if (boost::has_trivial_destructor<T>::value) {
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return std::copy(first, last, out); // will use memcpy if possible
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} else {
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for (; first != last; ++first, ++out) {
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*out = *first;
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first->~T();
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}
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return out;
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}
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}
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template< class Functor >
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void run_functor_and_delete( T * first, T * last, Functor & functor )
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{
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for (; first != last; ++first) {
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functor(*first);
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first->~T();
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}
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}
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template< class Functor >
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void run_functor_and_delete( T * first, T * last, Functor const & functor )
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{
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for (; first != last; ++first) {
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functor(*first);
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first->~T();
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}
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}
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};
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template <typename T, std::size_t MaxSize>
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class compile_time_sized_ringbuffer:
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public ringbuffer_base<T>
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{
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typedef std::size_t size_type;
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static const std::size_t max_size = MaxSize + 1;
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typedef typename boost::aligned_storage<max_size * sizeof(T),
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boost::alignment_of<T>::value
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>::type storage_type;
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storage_type storage_;
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T * data()
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{
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return static_cast<T*>(storage_.address());
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}
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const T * data() const
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{
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return static_cast<const T*>(storage_.address());
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}
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protected:
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size_type max_number_of_elements() const
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{
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return max_size;
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}
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public:
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bool push(T const & t)
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{
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return ringbuffer_base<T>::push(t, data(), max_size);
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}
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template <typename Functor>
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bool consume_one(Functor & f)
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{
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return ringbuffer_base<T>::consume_one(f, data(), max_size);
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}
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template <typename Functor>
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bool consume_one(Functor const & f)
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{
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return ringbuffer_base<T>::consume_one(f, data(), max_size);
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}
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template <typename Functor>
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size_type consume_all(Functor & f)
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{
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return ringbuffer_base<T>::consume_all(f, data(), max_size);
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}
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template <typename Functor>
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size_type consume_all(Functor const & f)
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{
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return ringbuffer_base<T>::consume_all(f, data(), max_size);
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}
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size_type push(T const * t, size_type size)
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{
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return ringbuffer_base<T>::push(t, size, data(), max_size);
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}
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template <size_type size>
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size_type push(T const (&t)[size])
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{
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return push(t, size);
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}
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template <typename ConstIterator>
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ConstIterator push(ConstIterator begin, ConstIterator end)
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{
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return ringbuffer_base<T>::push(begin, end, data(), max_size);
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}
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size_type pop(T * ret, size_type size)
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{
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return ringbuffer_base<T>::pop(ret, size, data(), max_size);
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}
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template <typename OutputIterator>
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size_type pop_to_output_iterator(OutputIterator it)
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{
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return ringbuffer_base<T>::pop_to_output_iterator(it, data(), max_size);
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}
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const T& front(void) const
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{
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return ringbuffer_base<T>::front(data());
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}
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T& front(void)
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{
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return ringbuffer_base<T>::front(data());
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}
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};
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template <typename T, typename Alloc>
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class runtime_sized_ringbuffer:
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public ringbuffer_base<T>,
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private Alloc
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{
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typedef std::size_t size_type;
|
|
size_type max_elements_;
|
|
typedef typename Alloc::pointer pointer;
|
|
pointer array_;
|
|
|
|
protected:
|
|
size_type max_number_of_elements() const
|
|
{
|
|
return max_elements_;
|
|
}
|
|
|
|
public:
|
|
explicit runtime_sized_ringbuffer(size_type max_elements):
|
|
max_elements_(max_elements + 1)
|
|
{
|
|
array_ = Alloc::allocate(max_elements_);
|
|
}
|
|
|
|
template <typename U>
|
|
runtime_sized_ringbuffer(typename Alloc::template rebind<U>::other const & alloc, size_type max_elements):
|
|
Alloc(alloc), max_elements_(max_elements + 1)
|
|
{
|
|
array_ = Alloc::allocate(max_elements_);
|
|
}
|
|
|
|
runtime_sized_ringbuffer(Alloc const & alloc, size_type max_elements):
|
|
Alloc(alloc), max_elements_(max_elements + 1)
|
|
{
|
|
array_ = Alloc::allocate(max_elements_);
|
|
}
|
|
|
|
~runtime_sized_ringbuffer(void)
|
|
{
|
|
// destroy all remaining items
|
|
T out;
|
|
while (pop(&out, 1)) {}
|
|
|
|
Alloc::deallocate(array_, max_elements_);
|
|
}
|
|
|
|
bool push(T const & t)
|
|
{
|
|
return ringbuffer_base<T>::push(t, &*array_, max_elements_);
|
|
}
|
|
|
|
template <typename Functor>
|
|
bool consume_one(Functor & f)
|
|
{
|
|
return ringbuffer_base<T>::consume_one(f, &*array_, max_elements_);
|
|
}
|
|
|
|
template <typename Functor>
|
|
bool consume_one(Functor const & f)
|
|
{
|
|
return ringbuffer_base<T>::consume_one(f, &*array_, max_elements_);
|
|
}
|
|
|
|
template <typename Functor>
|
|
size_type consume_all(Functor & f)
|
|
{
|
|
return ringbuffer_base<T>::consume_all(f, &*array_, max_elements_);
|
|
}
|
|
|
|
template <typename Functor>
|
|
size_type consume_all(Functor const & f)
|
|
{
|
|
return ringbuffer_base<T>::consume_all(f, &*array_, max_elements_);
|
|
}
|
|
|
|
size_type push(T const * t, size_type size)
|
|
{
|
|
return ringbuffer_base<T>::push(t, size, &*array_, max_elements_);
|
|
}
|
|
|
|
template <size_type size>
|
|
size_type push(T const (&t)[size])
|
|
{
|
|
return push(t, size);
|
|
}
|
|
|
|
template <typename ConstIterator>
|
|
ConstIterator push(ConstIterator begin, ConstIterator end)
|
|
{
|
|
return ringbuffer_base<T>::push(begin, end, &*array_, max_elements_);
|
|
}
|
|
|
|
size_type pop(T * ret, size_type size)
|
|
{
|
|
return ringbuffer_base<T>::pop(ret, size, &*array_, max_elements_);
|
|
}
|
|
|
|
template <typename OutputIterator>
|
|
size_type pop_to_output_iterator(OutputIterator it)
|
|
{
|
|
return ringbuffer_base<T>::pop_to_output_iterator(it, &*array_, max_elements_);
|
|
}
|
|
|
|
const T& front(void) const
|
|
{
|
|
return ringbuffer_base<T>::front(&*array_);
|
|
}
|
|
|
|
T& front(void)
|
|
{
|
|
return ringbuffer_base<T>::front(&*array_);
|
|
}
|
|
};
|
|
|
|
#ifdef BOOST_NO_CXX11_VARIADIC_TEMPLATES
|
|
template <typename T, typename A0, typename A1>
|
|
#else
|
|
template <typename T, typename ...Options>
|
|
#endif
|
|
struct make_ringbuffer
|
|
{
|
|
#ifdef BOOST_NO_CXX11_VARIADIC_TEMPLATES
|
|
typedef typename ringbuffer_signature::bind<A0, A1>::type bound_args;
|
|
#else
|
|
typedef typename ringbuffer_signature::bind<Options...>::type bound_args;
|
|
#endif
|
|
|
|
typedef extract_capacity<bound_args> extract_capacity_t;
|
|
|
|
static const bool runtime_sized = !extract_capacity_t::has_capacity;
|
|
static const size_t capacity = extract_capacity_t::capacity;
|
|
|
|
typedef extract_allocator<bound_args, T> extract_allocator_t;
|
|
typedef typename extract_allocator_t::type allocator;
|
|
|
|
// allocator argument is only sane, for run-time sized ringbuffers
|
|
BOOST_STATIC_ASSERT((mpl::if_<mpl::bool_<!runtime_sized>,
|
|
mpl::bool_<!extract_allocator_t::has_allocator>,
|
|
mpl::true_
|
|
>::type::value));
|
|
|
|
typedef typename mpl::if_c<runtime_sized,
|
|
runtime_sized_ringbuffer<T, allocator>,
|
|
compile_time_sized_ringbuffer<T, capacity>
|
|
>::type ringbuffer_type;
|
|
};
|
|
|
|
|
|
} /* namespace detail */
|
|
|
|
|
|
/** The spsc_queue class provides a single-writer/single-reader fifo queue, pushing and popping is wait-free.
|
|
*
|
|
* \b Policies:
|
|
* - \c boost::lockfree::capacity<>, optional <br>
|
|
* If this template argument is passed to the options, the size of the ringbuffer is set at compile-time.
|
|
*
|
|
* - \c boost::lockfree::allocator<>, defaults to \c boost::lockfree::allocator<std::allocator<T>> <br>
|
|
* Specifies the allocator that is used to allocate the ringbuffer. This option is only valid, if the ringbuffer is configured
|
|
* to be sized at run-time
|
|
*
|
|
* \b Requirements:
|
|
* - T must have a default constructor
|
|
* - T must be copyable
|
|
* */
|
|
#ifdef BOOST_NO_CXX11_VARIADIC_TEMPLATES
|
|
template <typename T, class A0, class A1>
|
|
#else
|
|
template <typename T, typename ...Options>
|
|
#endif
|
|
class spsc_queue:
|
|
#ifdef BOOST_NO_CXX11_VARIADIC_TEMPLATES
|
|
public detail::make_ringbuffer<T, A0, A1>::ringbuffer_type
|
|
#else
|
|
public detail::make_ringbuffer<T, Options...>::ringbuffer_type
|
|
#endif
|
|
{
|
|
private:
|
|
|
|
#ifndef BOOST_DOXYGEN_INVOKED
|
|
|
|
#ifdef BOOST_NO_CXX11_VARIADIC_TEMPLATES
|
|
typedef typename detail::make_ringbuffer<T, A0, A1>::ringbuffer_type base_type;
|
|
static const bool runtime_sized = detail::make_ringbuffer<T, A0, A1>::runtime_sized;
|
|
typedef typename detail::make_ringbuffer<T, A0, A1>::allocator allocator_arg;
|
|
#else
|
|
typedef typename detail::make_ringbuffer<T, Options...>::ringbuffer_type base_type;
|
|
static const bool runtime_sized = detail::make_ringbuffer<T, Options...>::runtime_sized;
|
|
typedef typename detail::make_ringbuffer<T, Options...>::allocator allocator_arg;
|
|
#endif
|
|
|
|
|
|
struct implementation_defined
|
|
{
|
|
typedef allocator_arg allocator;
|
|
typedef std::size_t size_type;
|
|
};
|
|
#endif
|
|
|
|
public:
|
|
typedef T value_type;
|
|
typedef typename implementation_defined::allocator allocator;
|
|
typedef typename implementation_defined::size_type size_type;
|
|
|
|
/** Constructs a spsc_queue
|
|
*
|
|
* \pre spsc_queue must be configured to be sized at compile-time
|
|
*/
|
|
// @{
|
|
spsc_queue(void)
|
|
{
|
|
BOOST_ASSERT(!runtime_sized);
|
|
}
|
|
|
|
template <typename U>
|
|
explicit spsc_queue(typename allocator::template rebind<U>::other const &)
|
|
{
|
|
// just for API compatibility: we don't actually need an allocator
|
|
BOOST_STATIC_ASSERT(!runtime_sized);
|
|
}
|
|
|
|
explicit spsc_queue(allocator const &)
|
|
{
|
|
// just for API compatibility: we don't actually need an allocator
|
|
BOOST_ASSERT(!runtime_sized);
|
|
}
|
|
// @}
|
|
|
|
|
|
/** Constructs a spsc_queue for element_count elements
|
|
*
|
|
* \pre spsc_queue must be configured to be sized at run-time
|
|
*/
|
|
// @{
|
|
explicit spsc_queue(size_type element_count):
|
|
base_type(element_count)
|
|
{
|
|
BOOST_ASSERT(runtime_sized);
|
|
}
|
|
|
|
template <typename U>
|
|
spsc_queue(size_type element_count, typename allocator::template rebind<U>::other const & alloc):
|
|
base_type(alloc, element_count)
|
|
{
|
|
BOOST_STATIC_ASSERT(runtime_sized);
|
|
}
|
|
|
|
spsc_queue(size_type element_count, allocator_arg const & alloc):
|
|
base_type(alloc, element_count)
|
|
{
|
|
BOOST_ASSERT(runtime_sized);
|
|
}
|
|
// @}
|
|
|
|
/** Pushes object t to the ringbuffer.
|
|
*
|
|
* \pre only one thread is allowed to push data to the spsc_queue
|
|
* \post object will be pushed to the spsc_queue, unless it is full.
|
|
* \return true, if the push operation is successful.
|
|
*
|
|
* \note Thread-safe and wait-free
|
|
* */
|
|
bool push(T const & t)
|
|
{
|
|
return base_type::push(t);
|
|
}
|
|
|
|
/** Pops one object from ringbuffer.
|
|
*
|
|
* \pre only one thread is allowed to pop data to the spsc_queue
|
|
* \post if ringbuffer is not empty, object will be discarded.
|
|
* \return true, if the pop operation is successful, false if ringbuffer was empty.
|
|
*
|
|
* \note Thread-safe and wait-free
|
|
*/
|
|
bool pop ()
|
|
{
|
|
detail::consume_noop consume_functor;
|
|
return consume_one( consume_functor );
|
|
}
|
|
|
|
/** Pops one object from ringbuffer.
|
|
*
|
|
* \pre only one thread is allowed to pop data to the spsc_queue
|
|
* \post if ringbuffer is not empty, object will be copied to ret.
|
|
* \return true, if the pop operation is successful, false if ringbuffer was empty.
|
|
*
|
|
* \note Thread-safe and wait-free
|
|
*/
|
|
template <typename U>
|
|
typename boost::enable_if<typename is_convertible<T, U>::type, bool>::type
|
|
pop (U & ret)
|
|
{
|
|
detail::consume_via_copy<U> consume_functor(ret);
|
|
return consume_one( consume_functor );
|
|
}
|
|
|
|
/** Pushes as many objects from the array t as there is space.
|
|
*
|
|
* \pre only one thread is allowed to push data to the spsc_queue
|
|
* \return number of pushed items
|
|
*
|
|
* \note Thread-safe and wait-free
|
|
*/
|
|
size_type push(T const * t, size_type size)
|
|
{
|
|
return base_type::push(t, size);
|
|
}
|
|
|
|
/** Pushes as many objects from the array t as there is space available.
|
|
*
|
|
* \pre only one thread is allowed to push data to the spsc_queue
|
|
* \return number of pushed items
|
|
*
|
|
* \note Thread-safe and wait-free
|
|
*/
|
|
template <size_type size>
|
|
size_type push(T const (&t)[size])
|
|
{
|
|
return push(t, size);
|
|
}
|
|
|
|
/** Pushes as many objects from the range [begin, end) as there is space .
|
|
*
|
|
* \pre only one thread is allowed to push data to the spsc_queue
|
|
* \return iterator to the first element, which has not been pushed
|
|
*
|
|
* \note Thread-safe and wait-free
|
|
*/
|
|
template <typename ConstIterator>
|
|
ConstIterator push(ConstIterator begin, ConstIterator end)
|
|
{
|
|
return base_type::push(begin, end);
|
|
}
|
|
|
|
/** Pops a maximum of size objects from ringbuffer.
|
|
*
|
|
* \pre only one thread is allowed to pop data to the spsc_queue
|
|
* \return number of popped items
|
|
*
|
|
* \note Thread-safe and wait-free
|
|
* */
|
|
size_type pop(T * ret, size_type size)
|
|
{
|
|
return base_type::pop(ret, size);
|
|
}
|
|
|
|
/** Pops a maximum of size objects from spsc_queue.
|
|
*
|
|
* \pre only one thread is allowed to pop data to the spsc_queue
|
|
* \return number of popped items
|
|
*
|
|
* \note Thread-safe and wait-free
|
|
* */
|
|
template <size_type size>
|
|
size_type pop(T (&ret)[size])
|
|
{
|
|
return pop(ret, size);
|
|
}
|
|
|
|
/** Pops objects to the output iterator it
|
|
*
|
|
* \pre only one thread is allowed to pop data to the spsc_queue
|
|
* \return number of popped items
|
|
*
|
|
* \note Thread-safe and wait-free
|
|
* */
|
|
template <typename OutputIterator>
|
|
typename boost::disable_if<typename is_convertible<T, OutputIterator>::type, size_type>::type
|
|
pop(OutputIterator it)
|
|
{
|
|
return base_type::pop_to_output_iterator(it);
|
|
}
|
|
|
|
/** consumes one element via a functor
|
|
*
|
|
* pops one element from the queue and applies the functor on this object
|
|
*
|
|
* \returns true, if one element was consumed
|
|
*
|
|
* \note Thread-safe and non-blocking, if functor is thread-safe and non-blocking
|
|
* */
|
|
template <typename Functor>
|
|
bool consume_one(Functor & f)
|
|
{
|
|
return base_type::consume_one(f);
|
|
}
|
|
|
|
/// \copydoc boost::lockfree::spsc_queue::consume_one(Functor & rhs)
|
|
template <typename Functor>
|
|
bool consume_one(Functor const & f)
|
|
{
|
|
return base_type::consume_one(f);
|
|
}
|
|
|
|
/** consumes all elements via a functor
|
|
*
|
|
* sequentially pops all elements from the queue and applies the functor on each object
|
|
*
|
|
* \returns number of elements that are consumed
|
|
*
|
|
* \note Thread-safe and non-blocking, if functor is thread-safe and non-blocking
|
|
* */
|
|
template <typename Functor>
|
|
size_type consume_all(Functor & f)
|
|
{
|
|
return base_type::consume_all(f);
|
|
}
|
|
|
|
/// \copydoc boost::lockfree::spsc_queue::consume_all(Functor & rhs)
|
|
template <typename Functor>
|
|
size_type consume_all(Functor const & f)
|
|
{
|
|
return base_type::consume_all(f);
|
|
}
|
|
|
|
/** get number of elements that are available for read
|
|
*
|
|
* \return number of available elements that can be popped from the spsc_queue
|
|
*
|
|
* \note Thread-safe and wait-free, should only be called from the consumer thread
|
|
* */
|
|
size_type read_available() const
|
|
{
|
|
return base_type::read_available(base_type::max_number_of_elements());
|
|
}
|
|
|
|
/** get write space to write elements
|
|
*
|
|
* \return number of elements that can be pushed to the spsc_queue
|
|
*
|
|
* \note Thread-safe and wait-free, should only be called from the producer thread
|
|
* */
|
|
size_type write_available() const
|
|
{
|
|
return base_type::write_available(base_type::max_number_of_elements());
|
|
}
|
|
|
|
/** get reference to element in the front of the queue
|
|
*
|
|
* Availability of front element can be checked using read_available().
|
|
*
|
|
* \pre only a consuming thread is allowed to check front element
|
|
* \pre read_available() > 0. If ringbuffer is empty, it's undefined behaviour to invoke this method.
|
|
* \return reference to the first element in the queue
|
|
*
|
|
* \note Thread-safe and wait-free
|
|
*/
|
|
const T& front() const
|
|
{
|
|
BOOST_ASSERT(read_available() > 0);
|
|
return base_type::front();
|
|
}
|
|
|
|
/// \copydoc boost::lockfree::spsc_queue::front() const
|
|
T& front()
|
|
{
|
|
BOOST_ASSERT(read_available() > 0);
|
|
return base_type::front();
|
|
}
|
|
|
|
/** reset the ringbuffer
|
|
*
|
|
* \note Not thread-safe
|
|
* */
|
|
void reset(void)
|
|
{
|
|
if ( !boost::has_trivial_destructor<T>::value ) {
|
|
// make sure to call all destructors!
|
|
|
|
T dummy_element;
|
|
while (pop(dummy_element))
|
|
{}
|
|
} else {
|
|
base_type::write_index_.store(0, memory_order_relaxed);
|
|
base_type::read_index_.store(0, memory_order_release);
|
|
}
|
|
}
|
|
};
|
|
|
|
} /* namespace lockfree */
|
|
} /* namespace boost */
|
|
|
|
|
|
#endif /* BOOST_LOCKFREE_SPSC_QUEUE_HPP_INCLUDED */
|