nuttx/libs/libc/time/lib_daysbeforemonth.c

/****************************************************************************
 * libs/libc/time/lib_daysbeforemonth.c
 *
 *   Copyright (C) 2009, 2011 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <stdint.h>
#include <stdbool.h>

#include <nuttx/time.h>

/****************************************************************************
 * Private Data
 ****************************************************************************/

static const uint16_t g_daysbeforemonth[13] =
{
  0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365
};

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name:  clock_daysbeforemonth
 *
 * Description:
 *    Get the number of days that occurred before the beginning of the
 *    month.
 *
 * Input Parameters:
 *    month    - The month in the form of tm_mon, that is a range of 0-11.
 *    leapyear - True if leap year and there are 29 days in February.
 *               NOTE the month=1 is February.
 *
 * Returned Value:
 *    The number of days that occurred before the month
 *
 ****************************************************************************/

int clock_daysbeforemonth(int month, bool leapyear)
{
  int retval = g_daysbeforemonth[month];
  if (month >= 2 && leapyear)
    {
      retval++;
    }

  return retval;
}