/******************************************************************************
* Copyright (c) 2015-2024 jiangxiaogang<kerndev@foxmail.com>
*
* This file is part of KLite distribution.
*
* KLite is free software, you can redistribute it and/or modify it under
* the MIT Licence.
*
* 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.
******************************************************************************/
#include "internal.h"
#include "kernel.h"

struct sem
{
	struct tcb_list list;
	uint32_t value;
};

sem_t sem_create(uint32_t value)
{
	struct sem *sem;
	sem = heap_alloc(NULL, sizeof(struct sem));
	if(sem != NULL)
	{
		memset(sem, 0, sizeof(struct sem));
		sem->value = value;
	}
	return (sem_t)sem;
}

void sem_delete(sem_t sem)
{
	heap_free(NULL, sem);
}

void sem_post(sem_t sem)
{
	cpu_enter_critical();
	if(sched_tcb_wake_from(&sem->list))
	{
		sched_preempt(false);
		cpu_leave_critical();
		return;
	}
	sem->value++;
	cpu_leave_critical();
}

void sem_wait(sem_t sem)
{
	cpu_enter_critical();
	if(sem->value > 0)
	{
		sem->value--;
		cpu_leave_critical();
		return;
	}
	sched_tcb_wait(sched_tcb_now, &sem->list);
	sched_switch();
	cpu_leave_critical();
}

uint32_t sem_timed_wait(sem_t sem, uint32_t timeout)
{
	cpu_enter_critical();
	if(sem->value > 0)
	{
		sem->value--;
		cpu_leave_critical();
		return true;
	}
	if(timeout == 0)
	{
		cpu_leave_critical();
		return false;
	}
	sched_tcb_timed_wait(sched_tcb_now, &sem->list, timeout);
	sched_switch();
	cpu_leave_critical();
	return sched_tcb_now->timeout;
}

uint32_t sem_value(sem_t sem)
{
	return sem->value;
}