quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker > Class Template Reference

Very fast threadsafe ring buffer log. More...

#include "ringbuffer_log.hpp"

Classes
class	iterator_
struct	unique_id
	Used to tag an index as being an absolute lookup of a unique counter value returned by push_back/emplace_back. More...

Public Types
using	container_type = typename Policy::container_type
using	value_type = typename container_type::value_type
	The log record type.
using	size_type = typename container_type::size_type
	The size type.
using	difference_type = typename container_type::difference_type
	The difference type.
using	reference = typename container_type::reference
	The reference type.
using	const_reference = typename container_type::const_reference
	The const reference type.
using	pointer = typename container_type::pointer
	The pointer type.
using	const_pointer = typename container_type::const_pointer
	The const pointer type.
using	iterator = iterator_< ringbuffer_log, pointer, reference >
	The iterator type.
using	const_iterator = iterator_< const ringbuffer_log, const_pointer, const_reference >
	The const iterator type.
using	reverse_iterator = std::reverse_iterator< iterator >
	The reverse iterator type.
using	const_reverse_iterator = std::reverse_iterator< const_iterator >
	The const reverse iterator type.

Public Member Functions
template<class... Args>
	ringbuffer_log (level starting_level, Args &&... args) noexcept(noexcept(container_type(std::forward< Args >(args)...)))
	Default construction, passes through args to container_type.
	ringbuffer_log (const ringbuffer_log &)=delete
	No copying.
	ringbuffer_log (ringbuffer_log &&)=delete
	No moving.
ringbuffer_log &	operator= (const ringbuffer_log &)=delete
	No copying.
ringbuffer_log &	operator= (ringbuffer_log &&)=delete
	No moving.
void	swap (ringbuffer_log &o) noexcept
	Swaps with another instance.
level	log_level () const noexcept
	THREADSAFE Returns the log level from the instance filtered by any LogLevelChecker.
level	instance_log_level () const noexcept
	THREADSAFE Returns the current per-instance log level.
void	instance_log_level (level new_level) noexcept
	THREADSAFE Sets the current per-instance log level.
bool	empty () const noexcept
	Returns true if the log is empty.
size_type	size () const noexcept
	Returns the number of items in the log.
size_type	max_size () const noexcept
	Returns the maximum number of items in the log.
std::ostream *	immediate () const noexcept
	Returns any std::ostream immediately printed to when a new log entry is added.
void	immediate (std::ostream *s) noexcept
	Set any std::ostream immediately printed to when a new log entry is added.
bool	valid (unique_id id) const noexcept
	True if a unique id is still valid.
reference	front () noexcept
	Returns the front of the ringbuffer. Be careful of races with concurrent modifies.
const_reference	front () const noexcept
	Returns the front of the ringbuffer. Be careful of races with concurrent modifies.
reference	operator[] (size_type pos) noexcept
	Returns a reference to the specified element. Be careful of races with concurrent modifies.
reference	operator[] (unique_id id) noexcept
	Returns a reference to the specified element.
const_reference	operator[] (size_type pos) const noexcept
	Returns a reference to the specified element. Be careful of races with concurrent modifies.
const_reference	operator[] (unique_id id) const noexcept
	Returns a reference to the specified element.
reference	back () noexcept
	Returns the back of the ringbuffer. Be careful of races with concurrent modifies.
const_reference	back () const noexcept
	Returns the back of the ringbuffer. Be careful of races with concurrent modifies.
iterator	begin () noexcept
	Returns an iterator to the first item in the log. Be careful of races with concurrent modifies.
const_iterator	begin () const noexcept
	Returns an iterator to the first item in the log. Be careful of races with concurrent modifies.
const_iterator	cbegin () const noexcept
	Returns an iterator to the first item in the log. Be careful of races with concurrent modifies.
iterator	end () noexcept
	Returns an iterator to the item after the last in the log. Be careful of races with concurrent modifies.
const_iterator	end () const noexcept
	Returns an iterator to the item after the last in the log. Be careful of races with concurrent modifies.
const_iterator	cend () const noexcept
	Returns an iterator to the item after the last in the log. Be careful of races with concurrent modifies.
void	clear () noexcept
	Clears the log.
size_type	push_back (value_type &&v) noexcept
	THREADSAFE Logs a new item, returning its unique counter id.
template<class... Args>
size_type	emplace_back (level __level, Args &&... args) noexcept
	THREADSAFE Logs a new item, returning its unique counter id.

Static Public Attributes
static constexpr size_t	max_items = Policy::max_items
	The maximum items to store according to Policy::max_items. If zero, use container's size().

Protected Member Functions
size_type	counter_to_idx (size_type counter) const noexcept

Protected Attributes
container_type	_store
std::atomic< level >	_instance_level
std::atomic< size_type >	_counter
std::ostream *	_immediate

Friends
template<class Parent , class Pointer , class Reference >
class	iterator_

Detailed Description

template<class Policy, class LogLevelChecker>
class quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >

Very fast threadsafe ring buffer log.

Works on the basis of an always incrementing atomic<size_t> which writes into the ring buffer at modulus of the ring buffer size. Items stored per log entry are defined by the Policy class' value_type. To log an item, call the QUICKCPPLIB_RINGBUFFERLOG_ITEM_* family of macros.

Be aware iteration, indexing etc. is most recent first, so log[0] is the most recently logged item. Use the reversed iterators if you don't want this.

For simple_ringbuffer_log_policy, typical item logging times are:

• without backtrace: 1.2 microseconds.

• with backtrace (windows): up to 33 microseconds.

  Todo:

  Implement STL allocator for a memory mapped file on disc so log survives sudden process exit.

Member Typedef Documentation

container_type

template<class Policy , class LogLevelChecker >

using quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::container_type = typename Policy::container_type

The container used to store the logged records set by Policy::container_type. Must be a ContiguousContainer.

value_type

template<class Policy , class LogLevelChecker >

using quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::value_type = typename container_type::value_type

The log record type.

size_type

template<class Policy , class LogLevelChecker >

using quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::size_type = typename container_type::size_type

The size type.

difference_type

template<class Policy , class LogLevelChecker >

using quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::difference_type = typename container_type::difference_type

The difference type.

reference

template<class Policy , class LogLevelChecker >

using quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::reference = typename container_type::reference

The reference type.

const_reference

template<class Policy , class LogLevelChecker >

using quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::const_reference = typename container_type::const_reference

The const reference type.

pointer

template<class Policy , class LogLevelChecker >

using quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::pointer = typename container_type::pointer

The pointer type.

const_pointer

template<class Policy , class LogLevelChecker >

using quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::const_pointer = typename container_type::const_pointer

The const pointer type.

iterator

template<class Policy , class LogLevelChecker >

using quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::iterator = iterator_<ringbuffer_log, pointer, reference>

The iterator type.

const_iterator

template<class Policy , class LogLevelChecker >

using quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::const_iterator = iterator_<const ringbuffer_log, const_pointer, const_reference>

The const iterator type.

reverse_iterator

template<class Policy , class LogLevelChecker >

using quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::reverse_iterator = std::reverse_iterator<iterator>

The reverse iterator type.

const_reverse_iterator

template<class Policy , class LogLevelChecker >

using quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::const_reverse_iterator = std::reverse_iterator<const_iterator>

The const reverse iterator type.

Constructor & Destructor Documentation

ringbuffer_log() [1/3]

template<class Policy , class LogLevelChecker >

template<class... Args>

quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::ringbuffer_log ( level  starting_level, Args &&...  args  )

inlineexplicitnoexcept

Default construction, passes through args to container_type.

        : _store(std::forward<Args>(args)...)
        , _instance_level(starting_level)
        , _counter(0)
        , _immediate(nullptr)
    {
    }

ringbuffer_log() [2/3]

template<class Policy , class LogLevelChecker >

quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::ringbuffer_log ( const ringbuffer_log< Policy, LogLevelChecker > &  )

delete

No copying.

ringbuffer_log() [3/3]

template<class Policy , class LogLevelChecker >

quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::ringbuffer_log ( ringbuffer_log< Policy, LogLevelChecker > &&  )

delete

No moving.

Member Function Documentation

counter_to_idx()

template<class Policy , class LogLevelChecker >

size_type quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::counter_to_idx ( size_type  counter ) const

inlineprotectednoexcept

{ return max_items ? (counter % max_items) : (counter % _store.size()); }

operator=() [1/2]

template<class Policy , class LogLevelChecker >

ringbuffer_log & quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::operator= ( const ringbuffer_log< Policy, LogLevelChecker > &  )

delete

No copying.

operator=() [2/2]

template<class Policy , class LogLevelChecker >

ringbuffer_log & quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::operator= ( ringbuffer_log< Policy, LogLevelChecker > &&  )

delete

No moving.

swap()

template<class Policy , class LogLevelChecker >

void quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::swap ( ringbuffer_log< Policy, LogLevelChecker > &  o )

inlinenoexcept

Swaps with another instance.

    {
      std::swap(_store, o._store);
      auto t = o._instance_level.load(std::memory_order_relaxed);
      o._instance_level.store(_instance_level.load(std::memory_order_relaxed), std::memory_order_relaxed);
      _instance_level.store(t, std::memory_order_relaxed);
      std::swap(_counter, o._counter);
      std::swap(_immediate, o._immediate);
    }

log_level()

template<class Policy , class LogLevelChecker >

level quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::log_level ( ) const

inlinenoexcept

THREADSAFE Returns the log level from the instance filtered by any LogLevelChecker.

{ return LogLevelChecker()(instance_log_level()); }

instance_log_level() [1/2]

template<class Policy , class LogLevelChecker >

level quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::instance_log_level ( ) const

inlinenoexcept

THREADSAFE Returns the current per-instance log level.

{ return _instance_level.load(std::memory_order_relaxed); }

instance_log_level() [2/2]

template<class Policy , class LogLevelChecker >

void quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::instance_log_level ( level  new_level )

inlinenoexcept

THREADSAFE Sets the current per-instance log level.

{ _instance_level.store(new_level, std::memory_order_relaxed); }

empty()

template<class Policy , class LogLevelChecker >

bool quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::empty ( ) const

inlinenoexcept

Returns true if the log is empty.

{ return _counter.load(std::memory_order_relaxed) == 0; }

size()

template<class Policy , class LogLevelChecker >

size_type quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::size ( ) const

inlinenoexcept

Returns the number of items in the log.

    {
      size_type ret = _counter.load(std::memory_order_relaxed);
      if(_store.size() < ret)
        ret = _store.size();
      return ret;
    }

max_size()

template<class Policy , class LogLevelChecker >

size_type quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::max_size ( ) const

inlinenoexcept

Returns the maximum number of items in the log.

{ return max_items ? max_items : _store.size(); }

immediate() [1/2]

template<class Policy , class LogLevelChecker >

std::ostream * quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::immediate ( ) const

inlinenoexcept

Returns any std::ostream immediately printed to when a new log entry is added.

{ return _immediate; }

immediate() [2/2]

template<class Policy , class LogLevelChecker >

void quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::immediate ( std::ostream *  s )

inlinenoexcept

Set any std::ostream immediately printed to when a new log entry is added.

{ _immediate = s; }

valid()

template<class Policy , class LogLevelChecker >

bool quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::valid ( unique_id  id ) const

inlinenoexcept

True if a unique id is still valid.

    {
      size_type counter = _counter.load(std::memory_order_relaxed);
      size_type size = counter;
      if(_store.size() < size)
        size = _store.size();
      return id.value < counter && id.value >= counter - size;
    }

front() [1/2]

template<class Policy , class LogLevelChecker >

reference quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::front ( )

inlinenoexcept

Returns the front of the ringbuffer. Be careful of races with concurrent modifies.

{ return _store[counter_to_idx(_counter.load(std::memory_order_relaxed) - 1)]; }

front() [2/2]

template<class Policy , class LogLevelChecker >

const_reference quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::front ( ) const

inlinenoexcept

Returns the front of the ringbuffer. Be careful of races with concurrent modifies.

{ return _store[counter_to_idx(_counter.load(std::memory_order_relaxed) - 1)]; }

operator[]() [1/4]

template<class Policy , class LogLevelChecker >

reference quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::operator[] ( size_type  pos )

inlinenoexcept

Returns a reference to the specified element. Be careful of races with concurrent modifies.

{ return _store[counter_to_idx(_counter.load(std::memory_order_relaxed) - 1 - pos)]; }

operator[]() [2/4]

template<class Policy , class LogLevelChecker >

reference quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::operator[] ( unique_id  id )

inlinenoexcept

Returns a reference to the specified element.

{ return _store[counter_to_idx(id.value)]; }

operator[]() [3/4]

template<class Policy , class LogLevelChecker >

const_reference quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::operator[] ( size_type  pos ) const

inlinenoexcept

Returns a reference to the specified element. Be careful of races with concurrent modifies.

{ return _store[counter_to_idx(_counter.load(std::memory_order_relaxed) - 1 - pos)]; }

operator[]() [4/4]

template<class Policy , class LogLevelChecker >

const_reference quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::operator[] ( unique_id  id ) const

inlinenoexcept

Returns a reference to the specified element.

{ return _store[counter_to_idx(id.value)]; }

back() [1/2]

template<class Policy , class LogLevelChecker >

reference quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::back ( )

inlinenoexcept

Returns the back of the ringbuffer. Be careful of races with concurrent modifies.

    {
      size_type counter = _counter.load(std::memory_order_relaxed);
      size_type size = counter;
      if(_store.size() < size)
        size = _store.size();
      return _store[counter_to_idx(counter - size)];
    }

back() [2/2]

template<class Policy , class LogLevelChecker >

const_reference quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::back ( ) const

inlinenoexcept

Returns the back of the ringbuffer. Be careful of races with concurrent modifies.

    {
      size_type counter = _counter.load(std::memory_order_relaxed);
      size_type size = counter;
      if(_store.size() < size)
        size = _store.size();
      return _store[counter_to_idx(counter - size)];
    }

begin() [1/2]

template<class Policy , class LogLevelChecker >

iterator quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::begin ( )

inlinenoexcept

Returns an iterator to the first item in the log. Be careful of races with concurrent modifies.

    {
      size_type counter = _counter.load(std::memory_order_relaxed);
      size_type size = counter;
      if(_store.size() < size)
        size = _store.size();
      return iterator(this, counter - 1, size);
    }

begin() [2/2]

template<class Policy , class LogLevelChecker >

const_iterator quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::begin ( ) const

inlinenoexcept

Returns an iterator to the first item in the log. Be careful of races with concurrent modifies.

    {
      size_type counter = _counter.load(std::memory_order_relaxed);
      size_type size = counter;
      if(_store.size() < size)
        size = _store.size();
      return const_iterator(this, counter - 1, size);
    }

cbegin()

template<class Policy , class LogLevelChecker >

const_iterator quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::cbegin ( ) const

inlinenoexcept

Returns an iterator to the first item in the log. Be careful of races with concurrent modifies.

    {
      size_type counter = _counter.load(std::memory_order_relaxed);
      size_type size = counter;
      if(_store.size() < size)
        size = _store.size();
      return const_iterator(this, counter - 1, size);
    }

end() [1/2]

template<class Policy , class LogLevelChecker >

iterator quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::end ( )

inlinenoexcept

Returns an iterator to the item after the last in the log. Be careful of races with concurrent modifies.

    {
      size_type counter = _counter.load(std::memory_order_relaxed);
      size_type size = counter;
      if(_store.size() < size)
        size = _store.size();
      return iterator(this, counter - 1 - size, 0);
    }

end() [2/2]

template<class Policy , class LogLevelChecker >

const_iterator quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::end ( ) const

inlinenoexcept

Returns an iterator to the item after the last in the log. Be careful of races with concurrent modifies.

    {
      size_type counter = _counter.load(std::memory_order_relaxed);
      size_type size = counter;
      if(_store.size() < size)
        size = _store.size();
      return const_iterator(this, counter - 1 - size, 0);
    }

cend()

template<class Policy , class LogLevelChecker >

const_iterator quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::cend ( ) const

inlinenoexcept

Returns an iterator to the item after the last in the log. Be careful of races with concurrent modifies.

    {
      size_type counter = _counter.load(std::memory_order_relaxed);
      size_type size = counter;
      if(_store.size() < size)
        size = _store.size();
      return const_iterator(this, counter - 1 - size, 0);
    }

clear()

template<class Policy , class LogLevelChecker >

void quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::clear ( )

inlinenoexcept

Clears the log.

    {
      _counter.store(0, std::memory_order_relaxed);
      std::fill(_store.begin(), _store.end(), value_type());
    }

push_back()

template<class Policy , class LogLevelChecker >

size_type quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::push_back ( value_type &&  v )

inlinenoexcept

THREADSAFE Logs a new item, returning its unique counter id.

    {
      if(static_cast<level>(v.level) <= log_level())
      {
        if(_immediate)
          *_immediate << v << std::endl;
        size_type thisitem = _counter++;
        v.counter = thisitem;
        _store[counter_to_idx(thisitem)] = std::move(v);
        return thisitem;
      }
      return (size_type) -1;
    }

emplace_back()

template<class Policy , class LogLevelChecker >

template<class... Args>

size_type quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::emplace_back ( level  __level, Args &&...  args  )

inlinenoexcept

THREADSAFE Logs a new item, returning its unique counter id.

    {
      if(__level <= log_level())
      {
        value_type v(__level, std::forward<Args>(args)...);
        if(_immediate)
          *_immediate << v << std::endl;
        size_type thisitem = _counter++;
        v.counter = thisitem;
        _store[counter_to_idx(thisitem)] = std::move(v);
        return thisitem;
      }
      return (size_type) -1;
    }

Friends And Related Symbol Documentation

iterator_

template<class Policy , class LogLevelChecker >

template<class Parent , class Pointer , class Reference >

friend class iterator_

friend

Member Data Documentation

max_items

template<class Policy , class LogLevelChecker >

constexpr size_t quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::max_items = Policy::max_items

staticconstexpr

The maximum items to store according to Policy::max_items. If zero, use container's size().

_store

template<class Policy , class LogLevelChecker >

container_type quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::_store

protected

_instance_level

template<class Policy , class LogLevelChecker >

std::atomic<level> quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::_instance_level

protected

_counter

template<class Policy , class LogLevelChecker >

std::atomic<size_type> quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::_counter

protected

_immediate

template<class Policy , class LogLevelChecker >

std::ostream* quickcpplib::_xxx::ringbuffer_log::ringbuffer_log< Policy, LogLevelChecker >::_immediate

protected

---

The documentation for this class was generated from the following file:

• include/quickcpplib/ringbuffer_log.hpp