os-semaphore.h

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/*
 * This file is part of the µOS++ project (https://micro-os-plus.github.io/).
 * Copyright (c) 2016-2025 Liviu Ionescu. All rights reserved.
 *
 * Permission to use, copy, modify, and/or distribute this software
 * for any purpose is hereby granted, under the terms of the MIT license.
 *
 * If a copy of the license was not distributed with this file, it can
 * be obtained from https://opensource.org/licenses/mit.
 */
 
#ifndef CMSIS_PLUS_RTOS_OS_SEMAPHORE_H_
#define CMSIS_PLUS_RTOS_OS_SEMAPHORE_H_
 
// ----------------------------------------------------------------------------
 
#if defined(__cplusplus)
 
// ----------------------------------------------------------------------------
 
#if defined(OS_USE_OS_APP_CONFIG_H)
#include <cmsis-plus/os-app-config.h>
#endif
 
#include <cmsis-plus/rtos/os-decls.h>
 
// ----------------------------------------------------------------------------
 
#pragma GCC diagnostic push
#if defined(__clang__)
#pragma clang diagnostic ignored "-Wc++98-compat"
#pragma clang diagnostic ignored "-Wdocumentation-unknown-command"
#endif
 
// ----------------------------------------------------------------------------
 
namespace os
{
  namespace rtos
  {
    // ========================================================================
 
#pragma GCC diagnostic push
#if defined(__clang__)
#pragma clang diagnostic ignored "-Wpadded"
#elif defined(__GNUC__)
#pragma GCC diagnostic ignored "-Wpadded"
#endif
 
    class semaphore : public internal::object_named_system
    {
    public:
      using count_t = int16_t;
 
      static constexpr count_t max_count_value = 0x7FFF;
 
      // ======================================================================
 
      class attributes : public internal::attributes_clocked
      {
      public:
        constexpr attributes ();
 
      protected:
        constexpr attributes (count_t max_value, count_t initial_value = 0);
 
      public:
        // The rule of five.
        attributes (const attributes&) = default;
        attributes (attributes&&) = default;
        attributes&
        operator= (const attributes&)
            = default;
        attributes&
        operator= (attributes&&)
            = default;
 
        ~attributes () = default;
 
      public:
        // Public members; no accessors and mutators required.
        // Warning: must match the type & order of the C file header.
        count_t sm_max_value = 1;
 
        count_t sm_initial_value = 0;
 
        // Add more attributes here.
 
      }; /* class attributes */
 
      // ======================================================================
      class attributes_binary : public attributes
      {
      public:
        constexpr attributes_binary (count_t initial_value);
 
        // The rule of five.
        attributes_binary (const attributes_binary&) = default;
        attributes_binary (attributes_binary&&) = default;
        attributes_binary&
        operator= (const attributes_binary&)
            = default;
        attributes_binary&
        operator= (attributes_binary&&)
            = default;
 
        ~attributes_binary () = default;
 
      }; /* class attributes_binary */
 
      static const attributes_binary initializer_binary;
 
      // ======================================================================
 
      class attributes_counting : public attributes
      {
      public:
        constexpr attributes_counting (count_t max_value,
                                       count_t initial_value);
 
        // The rule of five.
        attributes_counting (const attributes_counting&) = default;
        attributes_counting (attributes_counting&&) = default;
        attributes_counting&
        operator= (const attributes_counting&)
            = default;
        attributes_counting&
        operator= (attributes_counting&&)
            = default;
 
        ~attributes_counting () = default;
 
      }; /* class attributes_counting */
 
      // ======================================================================
      semaphore (const attributes& attr = initializer_binary);
 
      semaphore (const char* name,
                 const attributes& attr = initializer_binary);
 
    protected:
      semaphore (const char* name, const count_t max_value,
                 const count_t initial_value,
                 const attributes& attr = initializer_binary);
 
    public:
      // The rule of five.
      semaphore (const semaphore&) = delete;
      semaphore (semaphore&&) = delete;
      semaphore&
      operator= (const semaphore&)
          = delete;
      semaphore&
      operator= (semaphore&&)
          = delete;
 
      ~semaphore ();
 
      bool
      operator== (const semaphore& rhs) const;
 
    public:
      result_t
      post (void);
 
      result_t
      wait (void);
 
      result_t
      try_wait (void);
 
      result_t
      timed_wait (clock::duration_t timeout);
 
      count_t
      value (void) const;
 
      result_t
      reset (void);
 
      count_t
      initial_value (void) const;
 
      count_t
      max_value (void) const;
 
    protected:
      void
      internal_init_ (void);
 
      bool
      internal_try_wait_ (void);
 
    protected:
#if !defined(OS_USE_RTOS_PORT_SEMAPHORE)
      internal::waiting_threads_list list_;
      clock* clock_ = nullptr;
#endif
 
#if defined(OS_USE_RTOS_PORT_SEMAPHORE)
      friend class port::semaphore;
      os_semaphore_port_data_t port_;
#endif
 
      // Constant set during construction.
      const count_t max_value_ = max_count_value;
 
      const count_t initial_value_ = 0;
 
      // Can be updated in different contexts (interrupts or threads)
      volatile count_t count_ = 0;
 
      // Add more internal data.
 
    };
 
    // ========================================================================
 
    class semaphore_binary : public semaphore
    {
    public:
      semaphore_binary (const count_t initial_value);
 
      semaphore_binary (const char* name, const count_t initial_value);
 
      // The rule of five.
      semaphore_binary (const semaphore_binary&) = delete;
      semaphore_binary (semaphore_binary&&) = delete;
      semaphore_binary&
      operator= (const semaphore_binary&)
          = delete;
      semaphore_binary&
      operator= (semaphore_binary&&)
          = delete;
 
      ~semaphore_binary ();
 
      bool
      operator== (const semaphore_binary& rhs) const;
 
    };
 
    // ========================================================================
 
    class semaphore_counting : public semaphore
    {
    public:
      semaphore_counting (const count_t max_value,
                          const count_t initial_value);
 
      semaphore_counting (const char* name, const count_t max_value,
                          const count_t initial_value);
 
      // The rule of five.
      semaphore_counting (const semaphore_counting&) = delete;
      semaphore_counting (semaphore_counting&&) = delete;
      semaphore_counting&
      operator= (const semaphore_counting&)
          = delete;
      semaphore_counting&
      operator= (semaphore_counting&&)
          = delete;
 
      ~semaphore_counting ();
 
      bool
      operator== (const semaphore_counting& rhs) const;
 
    };
 
#pragma GCC diagnostic pop
 
    // ========================================================================
 
  } /* namespace rtos */
} /* namespace os */
 
// ===== Inline & template implementations ====================================
 
namespace os
{
  namespace rtos
  {
    // ========================================================================
 
    constexpr semaphore::attributes::attributes ()
    {
    }
 
    constexpr semaphore::attributes::attributes (count_t max_value,
                                                 count_t initial_value)
        : sm_max_value (max_value), //
          sm_initial_value (initial_value)
    {
    }
 
    // ========================================================================
    constexpr semaphore::attributes_binary::attributes_binary (
        count_t initial_value)
        : attributes{ 1, initial_value } // Use the protected constructor.
    {
    }
 
    // ========================================================================
 
    constexpr semaphore::attributes_counting::attributes_counting (
        count_t max_value, count_t initial_value)
        : attributes{ max_value, initial_value }
          // Use the protected constructor.
    {
    }
 
    // ========================================================================
 
    inline semaphore::semaphore (const attributes& attr)
        : semaphore{ nullptr, attr }
    {
    }
 
    inline bool
    semaphore::operator== (const semaphore& rhs) const
    {
      return this == &rhs;
    }
 
    inline semaphore::count_t
    semaphore::initial_value (void) const
    {
      return initial_value_;
    }
 
    inline semaphore::count_t
    semaphore::max_value (void) const
    {
      return max_value_;
    }
 
    // ========================================================================
 
    inline semaphore_binary::semaphore_binary (const count_t initial_value)
        : semaphore{ nullptr, 1, initial_value, initializer_binary }
    {
    }
 
    inline semaphore_binary::semaphore_binary (const char* name,
                                               const count_t initial_value)
        : semaphore{ name, 1, initial_value }
    {
    }
 
    inline semaphore_binary::~semaphore_binary ()
    {
    }
 
    // ========================================================================
 
    inline semaphore_counting::semaphore_counting (const count_t max_value,
                                                   const count_t initial_value)
        : semaphore{ nullptr, max_value, initial_value }
    {
    }
 
    inline semaphore_counting::semaphore_counting (const char* name,
                                                   const count_t max_value,
                                                   const count_t initial_value)
        : semaphore{ name, max_value, initial_value }
    {
    }
 
    inline semaphore_counting::~semaphore_counting ()
    {
    }
 
    // ========================================================================
 
  } /* namespace rtos */
} /* namespace os */
 
#pragma GCC diagnostic pop
 
// ----------------------------------------------------------------------------
 
#endif /* __cplusplus */
 
// ----------------------------------------------------------------------------
 
#endif /* CMSIS_PLUS_RTOS_OS_SEMAPHORE_H_ */