216 lines
6.3 KiB
C
216 lines
6.3 KiB
C
/************************************************************
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* gmtime_r.c
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*
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* Copyright (C) 2007 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name Gregory Nutt nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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************************************************************/
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/************************************************************
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* Included Files
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************************************************************/
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#include <sys/types.h>
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#include <time.h>
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#include <errno.h>
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#include <debug.h>
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#include "clock_internal.h"
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/************************************************************
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* Definitions
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************************************************************/
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/************************************************************
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* Private Type Declarations
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************************************************************/
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/************************************************************
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* Private Function Prototypes
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************************************************************/
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/* Calendar/UTC conversion routines */
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static void clock_utc2calendar(time_t utc, int *year, int *month, int *day);
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static void clock_utc2gregorian (time_t jdn, int *year, int *month, int *day);
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#ifdef CONFIG_JULIAN_TIME
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static void clock_utc2julian(time_t jdn, int *year, int *month, int *day);
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#endif /* CONFIG_JULIAN_TIME */
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/**********************************************************
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* Public Constant Data
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**********************************************************/
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/************************************************************
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* Public Variables
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************************************************************/
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/**********************************************************
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* Private Variables
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**********************************************************/
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/************************************************************
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* Private Functions
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************************************************************/
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/************************************************************
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* Function: clock_calendar2utc, clock_gregorian2utc,
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* and clock_julian2utc
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*
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* Description:
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* Calendar to UTC conversion routines. These conversions
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* are based on algorithms from p. 604 of Seidelman, P. K.
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* 1992. Explanatory Supplement to the Astronomical
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* Almanac. University Science Books, Mill Valley.
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*
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************************************************************/
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static void clock_utc2calendar(time_t utc, int *year, int *month, int *day)
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{
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#ifdef CONFIG_JULIAN_TIME
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if (utc >= GREG_DUTC)
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{
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clock_utc2gregorian(utc + JD_OF_EPOCH, year, month, day);
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}
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else
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{
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clock_utc2julian (utc + JD_OF_EPOCH, year, month, day);
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}
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#else /* CONFIG_JULIAN_TIME */
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clock_utc2gregorian(utc + JD_OF_EPOCH, year, month, day);
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#endif /* CONFIG_JULIAN_TIME */
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}
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static void clock_utc2gregorian(time_t jd, int *year, int *month, int *day)
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{
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long l, n, i, j, d, m, y;
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l = jd + 68569;
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n = (4*l) / 146097;
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l = l - (146097*n + 3)/4;
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i = (4000*(l+1))/1461001;
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l = l - (1461*i)/4 + 31;
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j = (80*l)/2447;
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d = l - (2447*j)/80;
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l = j/11;
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m = j + 2 - 12*l;
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y = 100*(n-49) + i + l;
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*year = y;
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*month = m;
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*day = d;
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}
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#ifdef CONFIG_JULIAN_TIME
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static void clock_utc2julian(time_t jd, int *year, int *month, int *day)
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{
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long j, k, l, n, d, i, m, y;
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j = jd + 1402;
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k = (j-1)/1461;
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l = j - 1461*k;
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n = (l-1)/365 - l/1461;
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i = l - 365*n + 30;
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j = (80*i)/2447;
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d = i - (2447*j)/80;
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i = j/11;
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m = j + 2 - 12*i;
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y = 4*k + n + i - 4716;
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*year = y;
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*month = m;
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*day = d;
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}
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#endif /* CONFIG_JULIAN_TIME */
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/************************************************************
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* Public Functions
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************************************************************/
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/************************************************************
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* Function: gmtime_r
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*
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* Description:
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* Time conversion (based on the POSIX API)
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*
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************************************************************/
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struct tm *gmtime_r(const time_t *clock, struct tm *result)
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{
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time_t time;
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time_t jdn;
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int year, month, day;
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int hour, min, sec;
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/* Get the seconds since the EPOCH */
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time = *clock;
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sdbg("clock=%d\n", (int)time);
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/* Convert to days, hours, minutes, and seconds since the EPOCH */
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jdn = time / (24*60*60);
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time -= (24*60*60) * jdn;
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hour = time / (60*60);
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time -= (60*60) * hour;
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min = time / 60;
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time -= 60 * min;
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sec = time;
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sdbg("hour=%d min=%d sec=%d\n",
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(int)hour, (int)min, (int)sec);
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/* Convert the days since the EPOCH to calendar day */
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clock_utc2calendar(jdn, &year, &month, &day);
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sdbg("jdn=%d year=%d month=%d day=%d\n",
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(int)jdn, (int)year, (int)month, (int)day);
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/* Then return the struct tm contents */
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result->tm_year = (int)year - 1900;
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result->tm_mon = (int)month - 1;
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result->tm_mday = (int)day;
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result->tm_hour = (int)hour;
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result->tm_min = (int)min;
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result->tm_sec = (int)sec;
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return result;
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}
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