stk_helper.h

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/*
 * SuperTinyKernel(TM) RTOS: Lightweight High-Performance Deterministic C++ RTOS for Embedded Systems.
 *
 * Source: https://github.com/SuperTinyKernel-RTOS
 *
 * Copyright (c) 2022-2026 Neutron Code Limited <stk@neutroncode.com>. All Rights Reserved.
 * License: MIT License, see LICENSE for a full text.
 */
 
#ifndef STK_HELPER_H_
#define STK_HELPER_H_
 
#include "stk_common.h"
#include "stk_arch.h"

 
namespace stk {

template <size_t _StackSize, EAccessMode _AccessMode>
class Task : public ITask
{
public:
    enum { STACK_SIZE = _StackSize }; 
 
    const Word *GetStack()      const override { return const_cast<Word *>(m_stack); }
    size_t GetStackSize()       const override { return _StackSize; }
    size_t GetStackSizeBytes()  const override { return _StackSize * sizeof(Word); }
    EAccessMode GetAccessMode() const override { return _AccessMode; }
 
protected:
    STK_NONCOPYABLE_CLASS(Task);

    Task() : m_stack()
    {}

    STK_VIRT_DTOR ~Task() = default;
 
private:
    typename StackMemoryDef<_StackSize>::Type m_stack; 
};

template <Weight _Weight, size_t _StackSize, EAccessMode _AccessMode>
class TaskW : public ITask
{
public:
    enum { STACK_SIZE = _StackSize }; 
 
    const Word *GetStack()      const override { return const_cast<Word *>(m_stack); }
    size_t GetStackSize()       const override { return _StackSize; }
    size_t GetStackSizeBytes()  const override { return _StackSize * sizeof(Word); }
    EAccessMode GetAccessMode() const override { return _AccessMode; }
    Weight GetWeight()          const override { return _Weight; }
 
protected:
    STK_NONCOPYABLE_CLASS(TaskW);

    TaskW() : m_stack() {}

    STK_VIRT_DTOR ~TaskW() = default;
 
private:
    typename StackMemoryDef<_StackSize>::Type m_stack; 
};

template <size_t _StackSize>
class StackMemoryWrapper : public IStackMemory
{
public:
    typedef typename StackMemoryDef<_StackSize>::Type MemoryType;

    explicit StackMemoryWrapper(MemoryType *stack) : m_stack(stack)
    {
        STK_STATIC_ASSERT(_StackSize >= STACK_SIZE_MIN);
    }

    STK_VIRT_DTOR ~StackMemoryWrapper() = default;

    const Word *GetStack() const override { return (*m_stack); }

    size_t GetStackSize() const override { return _StackSize; }

    size_t GetStackSizeBytes() const override { return (_StackSize * sizeof(Word)); }
 
private:
    MemoryType *m_stack; 
};
 
// Helper function for Kernel::UpdateTaskState.
template <bool TicklessMode> inline Timeout GetInitialSleepTicks();
template <> inline Timeout GetInitialSleepTicks<true>()  { return STK_TICKLESS_TICKS_MAX; }
template <> inline Timeout GetInitialSleepTicks<false>() { return 1; }

inline bool ISyncObject::Tick(Timeout elapsed_ticks)
{
    // note: ScopedCriticalSection usage
    //
    // Single-core: no critical section needed - Tick() runs inside the
    // SysTick ISR which already executes with interrupts disabled, making
    // re-entrancy impossible on the local core.
    //
    // Multi-core: critical section is required because the tick handler on
    // each core may call Tick() concurrently for the same Semaphore instance,
    // and ISyncObject::Tick() is not re-entrant.
#if (STK_ARCH_CPU_COUNT > 1)
    hw::CriticalSection::ScopedLock cs_;
#endif
 
    IWaitObject *itr = util::DListCast::ListEntryToParent<IWaitObject>(m_wait_list.GetFirst());
 
    while (itr != nullptr)
    {
        IWaitObject *const next = util::DListCast::ListEntryToParent<IWaitObject>(itr->GetNext());
 
        if (!itr->Tick(elapsed_ticks))
        {
            itr->Wake(true);
        }
 
        itr = next;
    }
 
    return !m_wait_list.IsEmpty();
}

inline Weight ISyncObject::FindWeightHigherThan(Weight comp) const
{
    Weight max_weight = NO_WEIGHT;
    const IWaitObject *itr = util::DListCast::ListEntryToParent<const IWaitObject>(m_wait_list.GetFirst());     
 
    while (itr != nullptr)
    {
        const Weight w = GetUserTaskFromTid(itr->GetTid())->GetWeight();
        if (w > max_weight)
        {
            max_weight = w;
        }
            
        itr = util::DListCast::ListEntryToParent<const IWaitObject>(itr->GetNext());
    }
 
    return ((max_weight > comp) ? max_weight : NO_WEIGHT);
}

inline TId ITask::GetId() const
{
    return GetTidFromUserTask(this);
}

static __stk_forceinline TId GetTid()
{
    return IKernelService::GetInstance()->GetTid();
}

static __stk_forceinline uint32_t GetTickResolution()
{
    return IKernelService::GetInstance()->GetTickResolution();
}

static __stk_forceinline Time GetMsFromTicks(Ticks tick_count, uint32_t resolution)
{
    return static_cast<Time>((tick_count * static_cast<Time>(resolution)) / 1000LL);
}

static __stk_forceinline Ticks GetTicksFromMs(Time ms, uint32_t resolution)
{
    Ticks tick_count = 0LL;
 
    if (resolution != 0U)
    {
        tick_count = static_cast<Ticks>((ms * 1000LL) / static_cast<Time>(resolution));
    }
 
    return tick_count;
}

static __stk_forceinline Ticks GetTicksFromMs(Time ms)
{
    return GetTicksFromMs(ms, GetTickResolution());
}

static __stk_forceinline Timeout GetTicksFromMsClampedToTimeout(Timeout ms)
{
    const Time time_ms = static_cast<Time>(ms);
    const Ticks tick_count = GetTicksFromMs(time_ms);    
    
    const Ticks final_ticks = (tick_count < static_cast<Ticks>(WAIT_INFINITE)) ? 
        tick_count : static_cast<Ticks>(WAIT_INFINITE);
        
    return static_cast<Timeout>(final_ticks);
}

static __stk_forceinline Ticks GetTicks()
{
    return IKernelService::GetInstance()->GetTicks();
}

static __stk_forceinline Time GetTimeNowMs()
{
    const IKernelService *const service = IKernelService::GetInstance();
    const uint32_t resolution = service->GetTickResolution();
    const Ticks tick_count = service->GetTicks();
 
    return ((resolution == 1000U) ? tick_count : 
        ((tick_count * static_cast<Ticks>(resolution)) / 1000LL));
}

static __stk_forceinline Cycles GetSysTimerCount()
{
    return IKernelService::GetInstance()->GetSysTimerCount();
}

static __stk_forceinline uint32_t GetSysTimerFrequency()
{
    return IKernelService::GetInstance()->GetSysTimerFrequency();
}

static __stk_forceinline void Sleep(Timeout tick_count)
{
    IKernelService::GetInstance()->Sleep(tick_count);
}

static __stk_forceinline void SleepMs(Timeout ms)
{
    Sleep(GetTicksFromMsClampedToTimeout(ms));
}

static __stk_forceinline bool SleepUntil(Ticks timestamp)
{
    return IKernelService::GetInstance()->SleepUntil(timestamp);
}

static __stk_forceinline void SleepCancel(TId task_id)
{
    IKernelService::GetInstance()->SleepCancel(task_id);
}

static __stk_forceinline void Yield()
{
    IKernelService::GetInstance()->SwitchToNext();
}

static __stk_forceinline void Delay(Timeout tick_count)
{
    IKernelService::GetInstance()->Delay(tick_count);
}

static __stk_forceinline void DelayMs(Timeout ms)
{
    Delay(GetTicksFromMsClampedToTimeout(ms));
}
 
} // namespace stk
 
#endif /* STK_HELPER_H_ */