1 /*
2 +----------------------------------------------------------------------+
3 | PHP Version 5 |
4 +----------------------------------------------------------------------+
5 | Copyright (c) 1997-2009 The PHP Group |
6 +----------------------------------------------------------------------+
7 | This source file is subject to version 3.01 of the PHP license, |
8 | that is bundled with this package in the file LICENSE, and is |
9 | available through the world-wide-web at the following url: |
10 | http://www.php.net/license/3_01.txt |
11 | If you did not receive a copy of the PHP license and are unable to |
12 | obtain it through the world-wide-web, please send a note to |
13 | license@php.net so we can mail you a copy immediately. |
14 +----------------------------------------------------------------------+
15 | Authors: Derick Rethans <derick@derickrethans.nl> |
16 +----------------------------------------------------------------------+
17 */
18
19 /* $Id: dow.c,v 1.8.2.3.2.6 2008/12/31 11:17:36 sebastian Exp $ */
20
21 #include "timelib.h"
22
23 static int m_table_common[13] = { -1, 0, 3, 3, 6, 1, 4, 6, 2, 5, 0, 3, 5 }; /* 1 = jan */
24 static int m_table_leap[13] = { -1, 6, 2, 3, 6, 1, 4, 6, 2, 5, 0, 3, 5 }; /* 1 = jan */
25
century_value(timelib_sll j)26 static timelib_sll century_value(timelib_sll j)
27 {
28 timelib_sll i = j - 17;
29 timelib_sll c = (4 - i * 2 + (i + 1) / 4) % 7;
30
31 return c < 0 ? c + 7 : c;
32 }
33
timelib_day_of_week_ex(timelib_sll y,timelib_sll m,timelib_sll d,int iso)34 static timelib_sll timelib_day_of_week_ex(timelib_sll y, timelib_sll m, timelib_sll d, int iso)
35 {
36 timelib_sll c1, y1, m1, dow;
37
38 /* Only valid for Gregorian calendar, commented out as we don't handle
39 * julian calendar. We just return the 'wrong' day of week to be
40 * consistent.
41 if (y < 1753) {
42 return -1;
43 } */
44 c1 = century_value(y / 100);
45 y1 = (y % 100);
46 m1 = timelib_is_leap(y) ? m_table_leap[m] : m_table_common[m];
47 dow = (c1 + y1 + m1 + (y1 / 4) + d) % 7;
48 if (iso) {
49 if (dow == 0) {
50 dow = 7;
51 }
52 }
53 return dow;
54 }
55
timelib_day_of_week(timelib_sll y,timelib_sll m,timelib_sll d)56 timelib_sll timelib_day_of_week(timelib_sll y, timelib_sll m, timelib_sll d)
57 {
58 return timelib_day_of_week_ex(y, m, d, 0);
59 }
60
timelib_iso_day_of_week(timelib_sll y,timelib_sll m,timelib_sll d)61 timelib_sll timelib_iso_day_of_week(timelib_sll y, timelib_sll m, timelib_sll d)
62 {
63 return timelib_day_of_week_ex(y, m, d, 1);
64 }
65
66 /* jan feb mar apr may jun jul aug sep oct nov dec */
67 static int d_table_common[13] = { 0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
68 static int d_table_leap[13] = { 0, 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335 };
69 static int ml_table_common[13] = { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
70 static int ml_table_leap[13] = { 0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
71
timelib_day_of_year(timelib_sll y,timelib_sll m,timelib_sll d)72 timelib_sll timelib_day_of_year(timelib_sll y, timelib_sll m, timelib_sll d)
73 {
74 return (timelib_is_leap(y) ? d_table_leap[m] : d_table_common[m]) + d - 1;
75 }
76
timelib_days_in_month(timelib_sll y,timelib_sll m)77 timelib_sll timelib_days_in_month(timelib_sll y, timelib_sll m)
78 {
79 return timelib_is_leap(y) ? ml_table_leap[m] : ml_table_common[m];
80 }
81
timelib_isoweek_from_date(timelib_sll y,timelib_sll m,timelib_sll d,timelib_sll * iw,timelib_sll * iy)82 void timelib_isoweek_from_date(timelib_sll y, timelib_sll m, timelib_sll d, timelib_sll *iw, timelib_sll *iy)
83 {
84 int y_leap, prev_y_leap, doy, jan1weekday, weekday;
85
86 y_leap = timelib_is_leap(y);
87 prev_y_leap = timelib_is_leap(y-1);
88 doy = timelib_day_of_year(y, m, d) + 1;
89 if (y_leap && m > 2) {
90 doy++;
91 }
92 jan1weekday = timelib_day_of_week(y, 1, 1);
93 weekday = timelib_day_of_week(y, m, d);
94 if (weekday == 0) weekday = 7;
95 if (jan1weekday == 0) jan1weekday = 7;
96 /* Find if Y M D falls in YearNumber Y-1, WeekNumber 52 or 53 */
97 if (doy <= (8 - jan1weekday) && jan1weekday > 4) {
98 *iy = y - 1;
99 if (jan1weekday == 5 || (jan1weekday == 6 && prev_y_leap)) {
100 *iw = 53;
101 } else {
102 *iw = 52;
103 }
104 } else {
105 *iy = y;
106 }
107 /* 8. Find if Y M D falls in YearNumber Y+1, WeekNumber 1 */
108 if (*iy == y) {
109 int i;
110
111 i = y_leap ? 366 : 365;
112 if ((i - (doy - y_leap)) < (4 - weekday)) {
113 *iy = y + 1;
114 *iw = 1;
115 return;
116 }
117 }
118 /* 9. Find if Y M D falls in YearNumber Y, WeekNumber 1 through 53 */
119 if (*iy == y) {
120 int j;
121
122 j = doy + (7 - weekday) + (jan1weekday - 1);
123 *iw = j / 7;
124 if (jan1weekday > 4) {
125 *iw -= 1;
126 }
127 }
128 }
129
timelib_daynr_from_weeknr(timelib_sll y,timelib_sll w,timelib_sll d)130 timelib_sll timelib_daynr_from_weeknr(timelib_sll y, timelib_sll w, timelib_sll d)
131 {
132 timelib_sll dow, day;
133
134 /* Figure out the dayofweek for y-1-1 */
135 dow = timelib_day_of_week(y, 1, 1);
136 /* then use that to figure out the offset for day 1 of week 1 */
137 day = 0 - (dow > 4 ? dow - 7 : dow);
138
139 /* Add weeks and days */
140 return day + ((w - 1) * 7) + d;
141 }
142
143 #if 0
144 int main(void)
145 {
146 printf("dow = %d\n", timelib_day_of_week(1978, 12, 22)); /* 5 */
147 printf("dow = %d\n", timelib_day_of_week(2005, 2, 19)); /* 6 */
148 }
149 #endif
150