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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_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_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(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 |