webpki/
calendar.rs

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1// Copyright 2015-2016 Brian Smith.
2//
3// Permission to use, copy, modify, and/or distribute this software for any
4// purpose with or without fee is hereby granted, provided that the above
5// copyright notice and this permission notice appear in all copies.
6//
7// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES
8// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
9// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
10// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
11// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
12// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
13// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
14
15use super::{time::Time, Error};
16
17pub(crate) fn time_from_ymdhms_utc(
18    year: u64,
19    month: u64,
20    day_of_month: u64,
21    hours: u64,
22    minutes: u64,
23    seconds: u64,
24) -> Result<Time, Error> {
25    let days_before_year_since_unix_epoch = days_before_year_since_unix_epoch(year)?;
26
27    const JAN: u64 = 31;
28    let feb = days_in_feb(year);
29    const MAR: u64 = 31;
30    const APR: u64 = 30;
31    const MAY: u64 = 31;
32    const JUN: u64 = 30;
33    const JUL: u64 = 31;
34    const AUG: u64 = 31;
35    const SEP: u64 = 30;
36    const OCT: u64 = 31;
37    const NOV: u64 = 30;
38    let days_before_month_in_year = match month {
39        1 => 0,
40        2 => JAN,
41        3 => JAN + feb,
42        4 => JAN + feb + MAR,
43        5 => JAN + feb + MAR + APR,
44        6 => JAN + feb + MAR + APR + MAY,
45        7 => JAN + feb + MAR + APR + MAY + JUN,
46        8 => JAN + feb + MAR + APR + MAY + JUN + JUL,
47        9 => JAN + feb + MAR + APR + MAY + JUN + JUL + AUG,
48        10 => JAN + feb + MAR + APR + MAY + JUN + JUL + AUG + SEP,
49        11 => JAN + feb + MAR + APR + MAY + JUN + JUL + AUG + SEP + OCT,
50        12 => JAN + feb + MAR + APR + MAY + JUN + JUL + AUG + SEP + OCT + NOV,
51        _ => unreachable!(), // `read_two_digits` already bounds-checked it.
52    };
53
54    let days_before =
55        days_before_year_since_unix_epoch + days_before_month_in_year + day_of_month - 1;
56
57    let seconds_since_unix_epoch =
58        (days_before * 24 * 60 * 60) + (hours * 60 * 60) + (minutes * 60) + seconds;
59
60    Ok(Time::from_seconds_since_unix_epoch(
61        seconds_since_unix_epoch,
62    ))
63}
64
65fn days_before_year_since_unix_epoch(year: u64) -> Result<u64, Error> {
66    // We don't support dates before January 1, 1970 because that is the
67    // Unix epoch. It is likely that other software won't deal well with
68    // certificates that have dates before the epoch.
69    if year < UNIX_EPOCH_YEAR {
70        return Err(Error::BadDerTime);
71    }
72    let days_before_year_ad = days_before_year_ad(year);
73    debug_assert!(days_before_year_ad >= DAYS_BEFORE_UNIX_EPOCH_AD);
74    Ok(days_before_year_ad - DAYS_BEFORE_UNIX_EPOCH_AD)
75}
76
77const UNIX_EPOCH_YEAR: u64 = 1970;
78
79fn days_before_year_ad(year: u64) -> u64 {
80    ((year - 1) * 365)
81        + ((year - 1) / 4)    // leap years are every 4 years,
82        - ((year - 1) / 100)  // except years divisible by 100,
83        + ((year - 1) / 400) // except years divisible by 400.
84}
85
86pub(crate) fn days_in_month(year: u64, month: u64) -> u64 {
87    match month {
88        1 | 3 | 5 | 7 | 8 | 10 | 12 => 31,
89        4 | 6 | 9 | 11 => 30,
90        2 => days_in_feb(year),
91        _ => unreachable!(), // `read_two_digits` already bounds-checked it.
92    }
93}
94
95fn days_in_feb(year: u64) -> u64 {
96    if (year % 4 == 0) && ((year % 100 != 0) || (year % 400 == 0)) {
97        29
98    } else {
99        28
100    }
101}
102
103#[allow(clippy::unreadable_literal)] // TODO: Make this clear.
104const DAYS_BEFORE_UNIX_EPOCH_AD: u64 = 719162;
105
106#[cfg(test)]
107mod tests {
108    #[test]
109    fn test_days_before_unix_epoch() {
110        use super::{days_before_year_ad, DAYS_BEFORE_UNIX_EPOCH_AD, UNIX_EPOCH_YEAR};
111        assert_eq!(
112            DAYS_BEFORE_UNIX_EPOCH_AD,
113            days_before_year_ad(UNIX_EPOCH_YEAR)
114        );
115    }
116
117    #[test]
118    fn test_days_before_year_since_unix_epoch() {
119        use super::{days_before_year_since_unix_epoch, Error, UNIX_EPOCH_YEAR};
120        assert_eq!(Ok(0), days_before_year_since_unix_epoch(UNIX_EPOCH_YEAR));
121        assert_eq!(
122            Ok(365),
123            days_before_year_since_unix_epoch(UNIX_EPOCH_YEAR + 1)
124        );
125        assert_eq!(
126            Err(Error::BadDerTime),
127            days_before_year_since_unix_epoch(UNIX_EPOCH_YEAR - 1)
128        );
129    }
130
131    #[test]
132    fn test_days_in_month() {
133        use super::days_in_month;
134        assert_eq!(days_in_month(2017, 1), 31);
135        assert_eq!(days_in_month(2017, 2), 28);
136        assert_eq!(days_in_month(2017, 3), 31);
137        assert_eq!(days_in_month(2017, 4), 30);
138        assert_eq!(days_in_month(2017, 5), 31);
139        assert_eq!(days_in_month(2017, 6), 30);
140        assert_eq!(days_in_month(2017, 7), 31);
141        assert_eq!(days_in_month(2017, 8), 31);
142        assert_eq!(days_in_month(2017, 9), 30);
143        assert_eq!(days_in_month(2017, 10), 31);
144        assert_eq!(days_in_month(2017, 11), 30);
145        assert_eq!(days_in_month(2017, 12), 31);
146
147        // leap cases
148        assert_eq!(days_in_month(2000, 2), 29);
149        assert_eq!(days_in_month(2004, 2), 29);
150        assert_eq!(days_in_month(2016, 2), 29);
151        assert_eq!(days_in_month(2100, 2), 28);
152    }
153
154    #[allow(clippy::unreadable_literal)] // TODO: Make this clear.
155    #[test]
156    fn test_time_from_ymdhms_utc() {
157        use super::{time_from_ymdhms_utc, Error, Time, UNIX_EPOCH_YEAR};
158
159        // 1969-12-31 00:00:00
160        assert_eq!(
161            Err(Error::BadDerTime),
162            time_from_ymdhms_utc(UNIX_EPOCH_YEAR - 1, 1, 1, 0, 0, 0)
163        );
164
165        // 1969-12-31 23:59:59
166        assert_eq!(
167            Err(Error::BadDerTime),
168            time_from_ymdhms_utc(UNIX_EPOCH_YEAR - 1, 12, 31, 23, 59, 59)
169        );
170
171        // 1970-01-01 00:00:00
172        assert_eq!(
173            Time::from_seconds_since_unix_epoch(0),
174            time_from_ymdhms_utc(UNIX_EPOCH_YEAR, 1, 1, 0, 0, 0).unwrap()
175        );
176
177        // 1970-01-01 00:00:01
178        assert_eq!(
179            Time::from_seconds_since_unix_epoch(1),
180            time_from_ymdhms_utc(UNIX_EPOCH_YEAR, 1, 1, 0, 0, 1).unwrap()
181        );
182
183        // 1971-01-01 00:00:00
184        assert_eq!(
185            Time::from_seconds_since_unix_epoch(365 * 86400),
186            time_from_ymdhms_utc(UNIX_EPOCH_YEAR + 1, 1, 1, 0, 0, 0).unwrap()
187        );
188
189        // year boundary
190        assert_eq!(
191            Time::from_seconds_since_unix_epoch(1483228799),
192            time_from_ymdhms_utc(2016, 12, 31, 23, 59, 59).unwrap()
193        );
194        assert_eq!(
195            Time::from_seconds_since_unix_epoch(1483228800),
196            time_from_ymdhms_utc(2017, 1, 1, 0, 0, 0).unwrap()
197        );
198
199        // not a leap year
200        assert_eq!(
201            Time::from_seconds_since_unix_epoch(1492449162),
202            time_from_ymdhms_utc(2017, 4, 17, 17, 12, 42).unwrap()
203        );
204
205        // leap year, post-feb
206        assert_eq!(
207            Time::from_seconds_since_unix_epoch(1460913162),
208            time_from_ymdhms_utc(2016, 4, 17, 17, 12, 42).unwrap()
209        );
210    }
211}
webpki/calendar.rs

webpki/
calendar.rs
