// Copyright (c) 2014 Adafruit Industries

// Author: Tony DiCola

// 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 <errno.h>

#include <sched.h>

#include <string.h>

#include <sys/time.h>

#include <time.h>

#include "common_dht_read.h"

void busy_wait_milliseconds(uint32_t millis) {

  // Set delay time period.

  struct timeval deltatime;

  deltatime.tv_sec = millis / 1000;

  deltatime.tv_usec = (millis % 1000) * 1000;

  struct timeval walltime;

  // Get current time and add delay to find end time.

  gettimeofday(&walltime, NULL);

  struct timeval endtime;

  timeradd(&walltime, &deltatime, &endtime);

  // Tight loop to waste time (and CPU) until enough time as elapsed.

  while (timercmp(&walltime, &endtime, <)) {

    gettimeofday(&walltime, NULL);

  }

}

void sleep_milliseconds(uint32_t millis) {

  struct timespec sleep;

  sleep.tv_sec = millis / 1000;

  sleep.tv_nsec = (millis % 1000) * 1000000L;

//  while (clock_nanosleep(CLOCK_MONOTONIC, 0, &sleep, &sleep) && errno == EINTR);

  while (nanosleep(&sleep, &sleep) && errno == EINTR);

}

void set_max_priority(void) {

  struct sched_param sched;

  memset(&sched, 0, sizeof(sched));

  // Use FIFO scheduler with highest priority for the lowest chance of the kernel context switching.

  sched.sched_priority = sched_get_priority_max(SCHED_FIFO);

  sched_setscheduler(0, SCHED_FIFO, &sched);

}

void set_default_priority(void) {

  struct sched_param sched;

  memset(&sched, 0, sizeof(sched));

  // Go back to default scheduler with default 0 priority.

  sched.sched_priority = 0;

  sched_setscheduler(0, SCHED_OTHER, &sched);

}