lab-rv32i-freertos-semaphore-notify/include/freertos/synchronization.hpp

#ifndef FREERTOS_CPP_SYNCHRONIZATION_HPP
#define FREERTOS_CPP_SYNCHRONIZATION_HPP

#include <stdint.h>
#include <type_traits>

extern "C"
{
#include "FreeRTOS.h"
#include "semphr.h"
#include "task.h"
}

namespace freertos
{

struct StaticSemaphoreStorage final
{
    StaticSemaphore_t control {};
};

class BinarySemaphore final
{
public:
    explicit BinarySemaphore( StaticSemaphoreStorage & storage ) noexcept
        : handle_ { xSemaphoreCreateBinaryStatic( &storage.control ) }
    {
    }

    ~BinarySemaphore() noexcept
    {
        if( handle_ != nullptr ) vSemaphoreDelete( handle_ );
    }

    BinarySemaphore( const BinarySemaphore & ) = delete;
    BinarySemaphore & operator=( const BinarySemaphore & ) = delete;
    BinarySemaphore( BinarySemaphore && ) = delete;
    BinarySemaphore & operator=( BinarySemaphore && ) = delete;

    [[nodiscard]] bool valid() const noexcept { return handle_ != nullptr; }
    [[nodiscard]] bool give() noexcept
    {
        return handle_ != nullptr && xSemaphoreGive( handle_ ) == pdPASS;
    }
    [[nodiscard]] bool take( TickType_t timeout ) noexcept
    {
        return handle_ != nullptr &&
               xSemaphoreTake( handle_, timeout ) == pdPASS;
    }
    [[nodiscard]] UBaseType_t count() const noexcept
    {
        return handle_ == nullptr ? 0U : uxSemaphoreGetCount( handle_ );
    }
    [[nodiscard]] SemaphoreHandle_t native_handle() const noexcept
    {
        return handle_;
    }

private:
    SemaphoreHandle_t handle_ {};
};

template< UBaseType_t Maximum >
class CountingSemaphore final
{
    static_assert( Maximum > 0U, "CountingSemaphore maximum must be positive" );

public:
    CountingSemaphore( StaticSemaphoreStorage & storage,
                       UBaseType_t initial ) noexcept
        : handle_ { initial <= Maximum ?
              xSemaphoreCreateCountingStatic(
                  Maximum, initial, &storage.control ) : nullptr }
    {
    }

    ~CountingSemaphore() noexcept
    {
        if( handle_ != nullptr ) vSemaphoreDelete( handle_ );
    }

    CountingSemaphore( const CountingSemaphore & ) = delete;
    CountingSemaphore & operator=( const CountingSemaphore & ) = delete;
    CountingSemaphore( CountingSemaphore && ) = delete;
    CountingSemaphore & operator=( CountingSemaphore && ) = delete;

    [[nodiscard]] bool valid() const noexcept { return handle_ != nullptr; }
    [[nodiscard]] bool give() noexcept
    {
        return handle_ != nullptr && xSemaphoreGive( handle_ ) == pdPASS;
    }
    [[nodiscard]] bool take( TickType_t timeout ) noexcept
    {
        return handle_ != nullptr &&
               xSemaphoreTake( handle_, timeout ) == pdPASS;
    }
    [[nodiscard]] UBaseType_t count() const noexcept
    {
        return handle_ == nullptr ? 0U : uxSemaphoreGetCount( handle_ );
    }
    static constexpr UBaseType_t maximum() noexcept { return Maximum; }
    [[nodiscard]] SemaphoreHandle_t native_handle() const noexcept
    {
        return handle_;
    }

private:
    SemaphoreHandle_t handle_ {};
};

enum class NotificationAction : uint8_t
{
    no_action,
    set_bits,
    increment,
    overwrite,
    without_overwrite
};

class TaskNotification final
{
public:
    explicit constexpr TaskNotification( TaskHandle_t target ) noexcept
        : target_ { target }
    {
    }

    [[nodiscard]] bool valid() const noexcept { return target_ != nullptr; }

    [[nodiscard]] bool give() const noexcept
    {
        return target_ != nullptr && xTaskNotifyGive( target_ ) == pdPASS;
    }

    [[nodiscard]] bool notify( uint32_t value,
                               NotificationAction action ) const noexcept
    {
        return target_ != nullptr &&
               xTaskNotify( target_, value, raw_action( action ) ) == pdPASS;
    }

    [[nodiscard]] static uint32_t take( bool clear_on_exit,
                                        TickType_t timeout ) noexcept
    {
        return ulTaskNotifyTake( clear_on_exit ? pdTRUE : pdFALSE, timeout );
    }

    [[nodiscard]] static bool wait_value( uint32_t & value,
                                          TickType_t timeout,
                                          uint32_t clear_on_entry = 0U,
                                          uint32_t clear_on_exit = UINT32_MAX ) noexcept
    {
        return xTaskNotifyWait( clear_on_entry, clear_on_exit,
                                &value, timeout ) == pdPASS;
    }

    [[nodiscard]] TaskHandle_t target() const noexcept { return target_; }

private:
    static eNotifyAction raw_action( NotificationAction action ) noexcept
    {
        switch( action )
        {
            case NotificationAction::no_action: return eNoAction;
            case NotificationAction::set_bits: return eSetBits;
            case NotificationAction::increment: return eIncrement;
            case NotificationAction::overwrite: return eSetValueWithOverwrite;
            case NotificationAction::without_overwrite:
                return eSetValueWithoutOverwrite;
        }
        return eNoAction;
    }

    TaskHandle_t target_ {};
};

static_assert( !std::is_copy_constructible< BinarySemaphore >::value );
static_assert( !std::is_move_constructible< CountingSemaphore< 2U > >::value );
static_assert( std::is_trivially_copyable< TaskNotification >::value );

} // namespace freertos

#endif