signal.h

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/******************************************************************************
The MIT License(MIT)
 
Embedded Template Library.
https://github.com/ETLCPP/etl
https://www.etlcpp.com
 
Copyright(c) 2025 John Wellbelove, Mark Kitson
 
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files(the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions :
 
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
 
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
******************************************************************************/
 
#ifndef ETL_SIGNAL_INCLUDED
#define ETL_SIGNAL_INCLUDED
 
#include <cstddef>
 
#include "platform.h"
 
#if ETL_NOT_USING_CPP11 && !defined(ETL_IN_UNIT_TEST)
  #error NOT SUPPORTED FOR C++03 OR BELOW
#endif
 
#if ETL_USING_CPP11
 
  #include "algorithm.h"
  #include "delegate.h"
  #include "error_handler.h"
  #include "exception.h"
  #include "file_error_numbers.h"
  #include "initializer_list.h"
  #include "iterator.h"
  #include "span.h"
  #include "type_traits.h"
 
//*****************************************************************************
//*****************************************************************************
 
namespace etl
{
  //***************************************************************************
  //***************************************************************************
  class signal_exception : public exception
  {
  public:
 
    signal_exception(string_type reason_, string_type file_name_, numeric_type line_number_)
      : exception{reason_, file_name_, line_number_}
    {
    }
  };
 
  //***************************************************************************
  //***************************************************************************
  class signal_full : public signal_exception
  {
  public:
 
    signal_full(string_type file_name_, numeric_type line_number_)
      : signal_exception{ETL_ERROR_TEXT("signal:full", ETL_SIGNAL_FILE_ID"A"), file_name_, line_number_}
    {
    }
  };
 
  //***************************************************************************
  //***************************************************************************
  template <typename TFunction, size_t Size, typename TSlot = etl::delegate<TFunction>>
  class signal
  {
  public:
 
    using slot_type = TSlot;
    using size_type = size_t;
    using span_type = etl::span<const slot_type>;
 
    //*************************************************************************
    //*************************************************************************
    template <typename... TSlots>
    ETL_CONSTEXPR14 explicit signal(TSlots&&... slots) ETL_NOEXCEPT
      : slot_list{etl::forward<TSlots>(slots)...}
      , slot_list_end{slot_list + sizeof...(slots)}
    {
      static_assert((etl::are_all_same<slot_type, etl::decay_t<TSlots>...>::value), "All slots must be slot_type");
      static_assert(sizeof...(slots) <= Size, "Number of slots exceeds capacity");
    }
 
    //*************************************************************************
    //*************************************************************************
    bool connect(const slot_type& slot) ETL_NOEXCEPT_EXPR(ETL_NOT_USING_EXCEPTIONS)
    {
      if (!connected(slot))
      {
        ETL_ASSERT_OR_RETURN_VALUE(!full(), ETL_ERROR(signal_full), false);
        append_slot(slot);
      }
 
      return true;
    }
 
  #if ETL_HAS_INITIALIZER_LIST && ETL_USING_CPP17
    //*************************************************************************
    //*************************************************************************
    bool connect(std::initializer_list<const slot_type> slots) ETL_NOEXCEPT_EXPR(ETL_NOT_USING_EXCEPTIONS)
    {
      for (const slot_type& slot : slots)
      {
        if (!connected(slot))
        {
          ETL_ASSERT_OR_RETURN_VALUE(!full(), ETL_ERROR(signal_full), false);
          append_slot(slot);
        }
      }
 
      return true;
    }
  #endif
 
    //*************************************************************************
    //*************************************************************************
    bool connect(const span_type slots) ETL_NOEXCEPT_EXPR(ETL_NOT_USING_EXCEPTIONS)
    {
      for (const slot_type& slot : slots)
      {
        if (!connected(slot))
        {
          ETL_ASSERT_OR_RETURN_VALUE(!full(), ETL_ERROR(signal_full), false);
          append_slot(slot);
        }
      }
 
      return true;
    }
 
    //*************************************************************************
    //*************************************************************************
    void disconnect(const slot_type& slot) ETL_NOEXCEPT
    {
      const auto end_itr = end();
      const auto itr     = etl::find(begin(), end_itr, slot);
 
      if (itr != end_itr)
      {
        // Shifts all elements after 'itr' one position to the left.
        etl::copy(etl::next(itr), end_itr, itr);
        slot_list_end = etl::prev(slot_list_end);
      }
    }
 
  #if ETL_HAS_INITIALIZER_LIST && ETL_USING_CPP17
    //*************************************************************************
    //*************************************************************************
    void disconnect(std::initializer_list<const slot_type> slots) ETL_NOEXCEPT
    {
      for (const slot_type& slot : slots)
      {
        disconnect(slot);
      }
    }
  #endif
 
    //*************************************************************************
    //*************************************************************************
    void disconnect(const span_type slots) ETL_NOEXCEPT
    {
      for (const slot_type& slot : slots)
      {
        disconnect(slot);
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    void disconnect_all() ETL_NOEXCEPT
    {
      slot_list_end = begin();
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bool connected(const slot_type& slot) const ETL_NOEXCEPT
    {
      return etl::any_of(begin(), end(), [&slot](const slot_type& s) { return s == slot; });
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bool empty() const ETL_NOEXCEPT
    {
      return begin() == end();
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 bool full() const ETL_NOEXCEPT
    {
      return size() == max_size();
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 size_type max_size() const ETL_NOEXCEPT
    {
      return Size;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 size_type size() const ETL_NOEXCEPT
    {
      return static_cast<size_type>(etl::distance(begin(), end()));
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 size_type available() const ETL_NOEXCEPT
    {
      return max_size() - size();
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename... TArgs>
    void operator()(TArgs&&... args) const ETL_NOEXCEPT
    {
      for (const slot_type& slot : *this)
      {
        if (slot_is_valid(slot))
        {
          slot(etl::forward<TArgs>(args)...);
        }
      }
    }
 
  private:
 
    using iterator       = slot_type*;
    using const_iterator = const slot_type*;
 
    slot_type slot_list[Size];
    iterator  slot_list_end;
 
    //*************************************************************************
    //*************************************************************************
    void append_slot(const slot_type& slot) ETL_NOEXCEPT
    {
      (*slot_list_end) = slot;
      slot_list_end    = etl::next(slot_list_end);
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TSlotType, typename... TArgs>
    static typename etl::enable_if_t<etl::is_delegate<TSlotType>::value, bool> slot_is_valid(const TSlotType& s) ETL_NOEXCEPT
    {
      return s.is_valid();
    }
 
    //*************************************************************************
    //*************************************************************************
    template <typename TSlotType, typename... TArgs>
    static typename etl::enable_if_t<!etl::is_delegate<TSlotType>::value, bool> slot_is_valid(const TSlotType&) ETL_NOEXCEPT
    {
      return true;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 iterator begin() ETL_NOEXCEPT
    {
      return slot_list;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 const_iterator begin() const ETL_NOEXCEPT
    {
      return slot_list;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 iterator end() ETL_NOEXCEPT
    {
      return slot_list_end;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_CONSTEXPR14 const_iterator end() const ETL_NOEXCEPT
    {
      return slot_list_end;
    }
  };
} // namespace etl
 
#endif
#endif