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86530b38 AT |
1 | # Date::Simple::NoXS - used internally by Date::Simple. |
2 | ||
3 | use strict; | |
4 | ||
5 | package Date::Simple; | |
6 | ||
7 | sub ymd { | |
8 | my $days = &ymd_to_days; | |
9 | return undef unless defined ($days); | |
10 | return (bless (\$days, __PACKAGE__)); | |
11 | } | |
12 | ||
13 | sub d8 { | |
14 | my ($d8) = @_; | |
15 | my @ymd = $d8 =~ m/^(\d{4})(\d\d)(\d\d)$/ or return undef; | |
16 | return ymd (@ymd); | |
17 | } | |
18 | ||
19 | # Precise integer arithmetic functions unfortunately missing from | |
20 | # Perl's core: | |
21 | ||
22 | sub _divmod { | |
23 | my ($quot, $int); | |
24 | ||
25 | $quot = $_[0] / $_[1]; | |
26 | $int = int($quot); | |
27 | $int -= 1 if $int > $quot; | |
28 | $_[0] %= $_[1]; | |
29 | return $int; | |
30 | }; | |
31 | ||
32 | sub _div { | |
33 | my ($quot, $int); | |
34 | ||
35 | $quot = $_[0] / $_[1]; | |
36 | $int = int($quot); | |
37 | return $int - 1 if $int > $quot; | |
38 | return $int; | |
39 | }; | |
40 | ||
41 | sub leap_year { | |
42 | my $y = shift; | |
43 | return (($y%4==0) and ($y%400==0 or $y%100!=0)) || 0; | |
44 | } | |
45 | ||
46 | my @days_in_month = ( | |
47 | [0,31,28,31,30,31,30,31,31,30,31,30,31], | |
48 | [0,31,29,31,30,31,30,31,31,30,31,30,31], | |
49 | ); | |
50 | ||
51 | sub days_in_month ($$) { | |
52 | my ($y,$m) = @_; | |
53 | return $days_in_month[leap_year($y)][$m]; | |
54 | } | |
55 | ||
56 | sub validate ($$$) { | |
57 | my ($y, $m, $d)= @_; | |
58 | # any +ve integral year is valid | |
59 | return 0 if $y != abs int $y; | |
60 | return 0 unless 1 <= $m and $m <= 12; | |
61 | return 0 unless 1 <= $d and $d <= $days_in_month[leap_year($y)][$m]; | |
62 | return 1; | |
63 | } | |
64 | ||
65 | # Given a year, month, and day, return the canonical day number. | |
66 | # That is the number of days since 1 January 1970, negative if earlier. | |
67 | sub ymd_to_days { | |
68 | my ($Y, $M, $D) = @_; | |
69 | my ($days, $x); | |
70 | ||
71 | if ($M < 1 || $M > 12 || $D < 1 || | |
72 | ($D > 28 && $D > days_in_month($Y, $M))) | |
73 | { | |
74 | return undef; | |
75 | } | |
76 | ||
77 | $days = $D + | |
78 | (undef, -1, 30, 58, 89, 119, 150, 180, 211, 242, 272, 303, 333)[$M]; | |
79 | $days += 365 * ($Y - 1970); | |
80 | $x = ($M <= 2 ? $Y-1 : $Y); | |
81 | $days += _div (($x - 1968), 4); | |
82 | $days -= _div (($x - 1900), 100); | |
83 | $days += _div (($x - 1600), 400); | |
84 | return $days; | |
85 | } | |
86 | ||
87 | sub days_since_1970 { ${$_[0]} } | |
88 | ||
89 | # Given a canonical day number (days since 1 Jan 1970), return the | |
90 | # year, month, and day. | |
91 | sub days_to_ymd { | |
92 | my ($days) = @_; | |
93 | my ($year, $mnum, $mday, $tmp); | |
94 | ||
95 | # Shift frame of reference from 1 Jan 1970 to (the imaginary) 1 Mar 0AD. | |
96 | $tmp = $days + 719468; | |
97 | ||
98 | # Do the math. | |
99 | $year = 400 * _divmod ($tmp, 146097); | |
100 | if ($tmp == 146096) { | |
101 | # Handle 29 Feb 2000, 2400, ... | |
102 | $year += 400; | |
103 | $mnum = 2; | |
104 | $mday = 29; | |
105 | } else { | |
106 | $year += 100 * _divmod ($tmp, 36524); | |
107 | $year += 4 * _divmod ($tmp, 1461); | |
108 | if ($tmp == 1460) { | |
109 | $year += 4; | |
110 | $mnum = 2; | |
111 | $mday = 29; | |
112 | } else { | |
113 | $year += _divmod ($tmp, 365); | |
114 | $mnum = _divmod ($tmp, 31); | |
115 | $mday = $tmp + (1, 1, 2, 2, 3, 3, 3, 4, 4, 5, 5, 5)[$mnum]; | |
116 | $tmp = (31, 30, 31, 30, 31, 31, 30, 31, 30, 31, 31, 28)[$mnum]; | |
117 | if ($mday > $tmp) { | |
118 | $mday -= $tmp; | |
119 | $mnum += 1; | |
120 | } | |
121 | if ($mnum > 9) { | |
122 | $mnum -= 9; | |
123 | $year += 1; | |
124 | } else { | |
125 | $mnum += 3; | |
126 | } | |
127 | } | |
128 | } | |
129 | return ($year, $mnum, $mday); | |
130 | } | |
131 | ||
132 | sub as_ymd { return days_to_ymd (${$_[0]}); } | |
133 | sub as_d8 { return sprintf ("%04d%02d%02d", &as_ymd); } | |
134 | ||
135 | sub year { return (&as_ymd) [0]; } | |
136 | sub month { return (&as_ymd) [1]; } | |
137 | sub day { return (&as_ymd) [2]; } | |
138 | ||
139 | sub day_of_week { | |
140 | return ((${$_[0]} + 4) % 7); | |
141 | } | |
142 | ||
143 | #------------------------------------------------------------------------------ | |
144 | # the following methods are called by the overloaded operators, so they should | |
145 | # not normally be called directly. | |
146 | #------------------------------------------------------------------------------ | |
147 | sub _stringify { return sprintf ("%04d-%02d-%02d", &as_ymd); } | |
148 | ||
149 | sub _add { | |
150 | my ($date, $diff) = @_; | |
151 | ||
152 | if ($diff !~ /^-?\d+$/) { | |
153 | Carp::croak ("Date interval must be an integer"); | |
154 | } | |
155 | return (bless (\ ($$date + $diff), ref($date))); | |
156 | } | |
157 | ||
158 | sub _subtract { | |
159 | my ($left, $right, $reverse) = @_; | |
160 | ||
161 | if ($reverse) { | |
162 | Carp::croak ("Can't subtract a date from a non-date"); | |
163 | } | |
164 | if (ref($right) eq '' && $right =~ /^-?\d+$/) { | |
165 | return (bless (\ ($$left - $right), ref($left))); | |
166 | } | |
167 | return ($$left - $$right); | |
168 | } | |
169 | ||
170 | sub _compare { | |
171 | my ($left, $right, $reverse) = @_; | |
172 | ||
173 | $right = $left->new($right) || _inval ($left, $right); | |
174 | return ($reverse ? $$right <=> $$left : $$left <=> $$right); | |
175 | } | |
176 | ||
177 | sub _eq { | |
178 | my ($left, $right) = @_; | |
179 | return (($right = $left->_new($right)) && $$right == $$left); | |
180 | } | |
181 | ||
182 | sub _ne { | |
183 | return (!&_eq); | |
184 | } | |
185 | ||
186 | 1; | |
187 | ||
188 | =head1 NAME | |
189 | ||
190 | Date::Simple::NoXS - Pure Perl support for Date::Simple. | |
191 | ||
192 | =head1 SYNOPSIS | |
193 | ||
194 | use Date::Simple; | |
195 | ||
196 | =head1 DESCRIPTION | |
197 | ||
198 | Used internally by Date::Simple. | |
199 | ||
200 | =head1 SEE ALSO | |
201 | ||
202 | L<Date::Simple>. | |
203 | ||
204 | =cut |