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/*
* Copyright (c) 2012-2014 Christian Hansen <chansen@cpan.org>
* <https://github.com/chansen/c-dt>
* All rights reserved.
*
* 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.
*
* 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 AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <assert.h>
#include "dt_core.h"
#define LEAP_YEAR(y) \
(((y) & 3) == 0 && ((y) % 100 != 0 || (y) % 400 == 0))
#define DAYS_IN_YEAR(y) \
(LEAP_YEAR(y) ? 366 : 365)
static const int days_preceding_month[2][13] = {
{ 0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 },
{ 0, 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335 }
};
static const int days_preceding_quarter[2][5] = {
{ 0, 0, 90, 181, 273 },
{ 0, 0, 91, 182, 274 }
};
dt_t
dt_from_rdn(int n) {
return n + DT_EPOCH_OFFSET;
}
dt_t
dt_from_yd(int y, int d) {
y--;
if (y < 0) {
const int n400 = 1 - y/400;
y += n400 * 400;
d -= n400 * 146097;
}
return 365 * y + y/4 - y/100 + y/400 + d + DT_EPOCH_OFFSET;
}
dt_t
dt_from_ymd(int y, int m, int d) {
if (m < 1 || m > 12) {
y += m / 12;
m %= 12;
if (m < 1)
y--, m += 12;
}
assert(m >= 1);
assert(m <= 12);
return dt_from_yd(y, days_preceding_month[LEAP_YEAR(y)][m] + d);
}
dt_t
dt_from_yqd(int y, int q, int d) {
if (q < 1 || q > 4) {
y += q / 4;
q %= 4;
if (q < 1)
y--, q += 4;
}
assert(q >= 1);
assert(q <= 4);
return dt_from_yd(y, days_preceding_quarter[LEAP_YEAR(y)][q] + d);
}
dt_t
dt_from_ywd(int y, int w, int d) {
dt_t dt;
dt = dt_from_yd(y, 4);
dt -= dt_dow(dt);
dt += w * 7 + d - 7;
return dt;
}
#ifndef DT_NO_SHORTCUTS
static const dt_t DT1901 = 693961 + DT_EPOCH_OFFSET; /* 1901-01-01 */
static const dt_t DT2099 = 766644 + DT_EPOCH_OFFSET; /* 2099-12-31 */
#endif
void
dt_to_yd(dt_t d, int *yp, int *dp) {
int y, n100, n1;
y = 0;
#ifndef DT_NO_SHORTCUTS
/* Shortcut dates between the years 1901-2099 inclusive */
if (d >= DT1901 && d <= DT2099) {
d -= DT1901 - 1;
y += (4 * d - 1) / 1461;
d -= (1461 * y) / 4;
y += 1901;
}
else
#endif
{
d -= DT_EPOCH_OFFSET;
if (d < 1) {
const int n400 = 1 - d/146097;
y -= n400 * 400;
d += n400 * 146097;
}
d--;
y += 400 * (d / 146097);
d %= 146097;
n100 = d / 36524;
y += 100 * n100;
d %= 36524;
y += 4 * (d / 1461);
d %= 1461;
n1 = d / 365;
y += n1;
d %= 365;
if (n100 == 4 || n1 == 4)
d = 366;
else
y++, d++;
}
if (yp) *yp = y;
if (dp) *dp = (int)d;
}
void
dt_to_ymd(dt_t dt, int *yp, int *mp, int *dp) {
int y, doy, m, l;
dt_to_yd(dt, &y, &doy);
l = LEAP_YEAR(y);
m = doy < 32 ? 1 : 1 + (5 * (doy - 59 - l) + 303) / 153;
assert(m >= 1);
assert(m <= 12);
if (yp) *yp = y;
if (mp) *mp = m;
if (dp) *dp = doy - days_preceding_month[l][m];
}
void
dt_to_yqd(dt_t dt, int *yp, int *qp, int *dp) {
int y, doy, q, l;
dt_to_yd(dt, &y, &doy);
l = LEAP_YEAR(y);
q = doy < 91 ? 1 : 1 + (5 * (doy - 59 - l) + 303) / 459;
assert(q >= 1);
assert(q <= 4);
if (yp) *yp = y;
if (qp) *qp = q;
if (dp) *dp = doy - days_preceding_quarter[l][q];
}
void
dt_to_ywd(dt_t dt, int *yp, int *wp, int *dp) {
int y, doy, dow;
dt_to_yd(dt, &y, &doy);
dow = dt_dow(dt);
doy = doy + 4 - dow;
if (doy < 1) {
y--;
doy += DAYS_IN_YEAR(y);
}
else if (doy > 365) {
const int diy = DAYS_IN_YEAR(y);
if (doy > diy) {
doy -= diy;
y++;
}
}
if (yp) *yp = y;
if (wp) *wp = (doy + 6) / 7;
if (dp) *dp = dow;
}
int
dt_rdn(dt_t dt) {
return dt - DT_EPOCH_OFFSET;
}
dt_dow_t
dt_dow(dt_t dt) {
int dow = (dt - DT_EPOCH_OFFSET) % 7;
if (dow < 1)
dow += 7;
assert(dow >= 1);
assert(dow <= 7);
return dow;
}
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