1 | /* Copyright (c) 2002,2003 CrystalClear Software, Inc. |
2 | * Use, modification and distribution is subject to the |
3 | * Boost Software License, Version 1.0. (See accompanying |
4 | * file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt) |
5 | * Author: Jeff Garland, Bart Garst |
6 | * $Date$ |
7 | */ |
8 | |
9 | #ifndef NO_BOOST_DATE_TIME_INLINE |
10 | #undef BOOST_DATE_TIME_INLINE |
11 | #define BOOST_DATE_TIME_INLINE inline |
12 | #endif |
13 | |
14 | namespace boost { |
15 | namespace date_time { |
16 | //! Return the day of the week (0==Sunday, 1==Monday, etc) |
17 | /*! Converts a year-month-day into a day of the week number |
18 | */ |
19 | template<typename ymd_type_, typename date_int_type_> |
20 | BOOST_DATE_TIME_INLINE |
21 | unsigned short |
22 | gregorian_calendar_base<ymd_type_,date_int_type_>::day_of_week(const ymd_type& ymd) { |
23 | unsigned short a = static_cast<unsigned short>((14-ymd.month)/12); |
24 | unsigned short y = static_cast<unsigned short>(ymd.year - a); |
25 | unsigned short m = static_cast<unsigned short>(ymd.month + 12*a - 2); |
26 | unsigned short d = static_cast<unsigned short>((ymd.day + y + (y/4) - (y/100) + (y/400) + (31*m)/12) % 7); |
27 | //std::cout << year << "-" << month << "-" << day << " is day: " << d << "\n"; |
28 | return d; |
29 | } |
30 | |
31 | //!Return the iso week number for the date |
32 | /*!Implements the rules associated with the iso 8601 week number. |
33 | Basically the rule is that Week 1 of the year is the week that contains |
34 | January 4th or the week that contains the first Thursday in January. |
35 | Reference for this algorithm is the Calendar FAQ by Claus Tondering, April 2000. |
36 | */ |
37 | template<typename ymd_type_, typename date_int_type_> |
38 | BOOST_DATE_TIME_INLINE |
39 | int |
40 | gregorian_calendar_base<ymd_type_,date_int_type_>::week_number(const ymd_type& ymd) { |
41 | unsigned long julianbegin = julian_day_number(ymd: ymd_type(ymd.year,1,1)); |
42 | unsigned long juliantoday = julian_day_number(ymd); |
43 | unsigned long day = (julianbegin + 3) % 7; |
44 | unsigned long week = (juliantoday + day - julianbegin + 4)/7; |
45 | |
46 | if ((week >= 1) && (week <= 52)) { |
47 | return static_cast<int>(week); |
48 | } |
49 | |
50 | if (week == 53) { |
51 | if((day==6) ||(day == 5 && is_leap_year(ymd.year))) { |
52 | return static_cast<int>(week); //under these circumstances week == 53. |
53 | } else { |
54 | return 1; //monday - wednesday is in week 1 of next year |
55 | } |
56 | } |
57 | //if the week is not in current year recalculate using the previous year as the beginning year |
58 | else if (week == 0) { |
59 | julianbegin = julian_day_number(ymd: ymd_type(static_cast<unsigned short>(ymd.year-1),1,1)); |
60 | juliantoday = julian_day_number(ymd); |
61 | day = (julianbegin + 3) % 7; |
62 | week = (juliantoday + day - julianbegin + 4)/7; |
63 | return static_cast<int>(week); |
64 | } |
65 | |
66 | return static_cast<int>(week); //not reachable -- well except if day == 5 and is_leap_year != true |
67 | |
68 | } |
69 | |
70 | //! Convert a ymd_type into a day number |
71 | /*! The day number is an absolute number of days since the start of count |
72 | */ |
73 | template<typename ymd_type_, typename date_int_type_> |
74 | BOOST_DATE_TIME_INLINE |
75 | date_int_type_ |
76 | gregorian_calendar_base<ymd_type_,date_int_type_>::day_number(const ymd_type& ymd) |
77 | { |
78 | unsigned short a = static_cast<unsigned short>((14-ymd.month)/12); |
79 | unsigned short y = static_cast<unsigned short>(ymd.year + 4800 - a); |
80 | unsigned short m = static_cast<unsigned short>(ymd.month + 12*a - 3); |
81 | unsigned long d = ymd.day + ((153*m + 2)/5) + 365*y + (y/4) - (y/100) + (y/400) - 32045; |
82 | return static_cast<date_int_type>(d); |
83 | } |
84 | |
85 | //! Convert a year-month-day into the julian day number |
86 | /*! Since this implementation uses julian day internally, this is the same as the day_number. |
87 | */ |
88 | template<typename ymd_type_, typename date_int_type_> |
89 | BOOST_DATE_TIME_INLINE |
90 | date_int_type_ |
91 | gregorian_calendar_base<ymd_type_,date_int_type_>::julian_day_number(const ymd_type& ymd) |
92 | { |
93 | return day_number(ymd); |
94 | } |
95 | |
96 | //! Convert year-month-day into a modified julian day number |
97 | /*! The day number is an absolute number of days. |
98 | * MJD 0 thus started on 17 Nov 1858(Gregorian) at 00:00:00 UTC |
99 | */ |
100 | template<typename ymd_type_, typename date_int_type_> |
101 | BOOST_DATE_TIME_INLINE |
102 | date_int_type_ |
103 | gregorian_calendar_base<ymd_type_,date_int_type_>::modjulian_day_number(const ymd_type& ymd) |
104 | { |
105 | return julian_day_number(ymd)-2400001; //prerounded |
106 | } |
107 | |
108 | //! Change a day number into a year-month-day |
109 | template<typename ymd_type_, typename date_int_type_> |
110 | BOOST_DATE_TIME_INLINE |
111 | ymd_type_ |
112 | gregorian_calendar_base<ymd_type_,date_int_type_>::from_day_number(date_int_type dayNumber) |
113 | { |
114 | date_int_type a = dayNumber + 32044; |
115 | date_int_type b = (4*a + 3)/146097; |
116 | date_int_type c = a-((146097*b)/4); |
117 | date_int_type d = (4*c + 3)/1461; |
118 | date_int_type e = c - (1461*d)/4; |
119 | date_int_type m = (5*e + 2)/153; |
120 | unsigned short day = static_cast<unsigned short>(e - ((153*m + 2)/5) + 1); |
121 | unsigned short month = static_cast<unsigned short>(m + 3 - 12 * (m/10)); |
122 | year_type year = static_cast<unsigned short>(100*b + d - 4800 + (m/10)); |
123 | //std::cout << year << "-" << month << "-" << day << "\n"; |
124 | |
125 | return ymd_type(static_cast<unsigned short>(year),month,day); |
126 | } |
127 | |
128 | //! Change a day number into a year-month-day |
129 | template<typename ymd_type_, typename date_int_type_> |
130 | BOOST_DATE_TIME_INLINE |
131 | ymd_type_ |
132 | gregorian_calendar_base<ymd_type_,date_int_type_>::from_julian_day_number(date_int_type dayNumber) |
133 | { |
134 | date_int_type a = dayNumber + 32044; |
135 | date_int_type b = (4*a+3)/146097; |
136 | date_int_type c = a - ((146097*b)/4); |
137 | date_int_type d = (4*c + 3)/1461; |
138 | date_int_type e = c - ((1461*d)/4); |
139 | date_int_type m = (5*e + 2)/153; |
140 | unsigned short day = static_cast<unsigned short>(e - ((153*m + 2)/5) + 1); |
141 | unsigned short month = static_cast<unsigned short>(m + 3 - 12 * (m/10)); |
142 | year_type year = static_cast<year_type>(100*b + d - 4800 + (m/10)); |
143 | //std::cout << year << "-" << month << "-" << day << "\n"; |
144 | |
145 | return ymd_type(year,month,day); |
146 | } |
147 | |
148 | //! Change a modified julian day number into a year-month-day |
149 | template<typename ymd_type_, typename date_int_type_> |
150 | BOOST_DATE_TIME_INLINE |
151 | ymd_type_ |
152 | gregorian_calendar_base<ymd_type_,date_int_type_>::from_modjulian_day_number(date_int_type dayNumber) { |
153 | date_int_type jd = dayNumber + 2400001; //is 2400000.5 prerounded |
154 | return from_julian_day_number(dayNumber: jd); |
155 | } |
156 | |
157 | //! Determine if the provided year is a leap year |
158 | /*! |
159 | *@return true if year is a leap year, false otherwise |
160 | */ |
161 | template<typename ymd_type_, typename date_int_type_> |
162 | BOOST_DATE_TIME_INLINE |
163 | bool |
164 | gregorian_calendar_base<ymd_type_,date_int_type_>::is_leap_year(year_type year) |
165 | { |
166 | //divisible by 4, not if divisible by 100, but true if divisible by 400 |
167 | return (!(year % 4)) && ((year % 100) || (!(year % 400))); |
168 | } |
169 | |
170 | //! Calculate the last day of the month |
171 | /*! Find the day which is the end of the month given year and month |
172 | * No error checking is performed. |
173 | */ |
174 | template<typename ymd_type_, typename date_int_type_> |
175 | BOOST_DATE_TIME_INLINE |
176 | unsigned short |
177 | gregorian_calendar_base<ymd_type_,date_int_type_>::end_of_month_day(year_type year, |
178 | month_type month) |
179 | { |
180 | switch (month) { |
181 | case 2: |
182 | if (is_leap_year(year)) { |
183 | return 29; |
184 | } else { |
185 | return 28; |
186 | }; |
187 | case 4: |
188 | case 6: |
189 | case 9: |
190 | case 11: |
191 | return 30; |
192 | default: |
193 | return 31; |
194 | }; |
195 | |
196 | } |
197 | |
198 | //! Provide the ymd_type specification for the calandar start |
199 | template<typename ymd_type_, typename date_int_type_> |
200 | BOOST_DATE_TIME_INLINE |
201 | ymd_type_ |
202 | gregorian_calendar_base<ymd_type_,date_int_type_>::epoch() |
203 | { |
204 | return ymd_type(1400,1,1); |
205 | } |
206 | |
207 | //! Defines length of a week for week calculations |
208 | template<typename ymd_type_, typename date_int_type_> |
209 | BOOST_DATE_TIME_INLINE |
210 | unsigned short |
211 | gregorian_calendar_base<ymd_type_,date_int_type_>::days_in_week() |
212 | { |
213 | return 7; |
214 | } |
215 | |
216 | |
217 | } } //namespace gregorian |
218 | |
219 | |
220 | |