httpdate/
date.rs

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1use std::cmp;
2use std::fmt::{self, Display, Formatter};
3use std::str::FromStr;
4use std::time::{Duration, SystemTime, UNIX_EPOCH};
5
6use crate::Error;
7
8/// HTTP timestamp type.
9///
10/// Parse using `FromStr` impl.
11/// Format using the `Display` trait.
12/// Convert timestamp into/from `SytemTime` to use.
13/// Supports comparsion and sorting.
14#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
15pub struct HttpDate {
16    /// 0...59
17    sec: u8,
18    /// 0...59
19    min: u8,
20    /// 0...23
21    hour: u8,
22    /// 1...31
23    day: u8,
24    /// 1...12
25    mon: u8,
26    /// 1970...9999
27    year: u16,
28    /// 1...7
29    wday: u8,
30}
31
32impl HttpDate {
33    fn is_valid(&self) -> bool {
34        self.sec < 60
35            && self.min < 60
36            && self.hour < 24
37            && self.day > 0
38            && self.day < 32
39            && self.mon > 0
40            && self.mon <= 12
41            && self.year >= 1970
42            && self.year <= 9999
43            && &HttpDate::from(SystemTime::from(*self)) == self
44    }
45}
46
47impl From<SystemTime> for HttpDate {
48    fn from(v: SystemTime) -> HttpDate {
49        let dur = v
50            .duration_since(UNIX_EPOCH)
51            .expect("all times should be after the epoch");
52        let secs_since_epoch = dur.as_secs();
53
54        if secs_since_epoch >= 253402300800 {
55            // year 9999
56            panic!("date must be before year 9999");
57        }
58
59        /* 2000-03-01 (mod 400 year, immediately after feb29 */
60        const LEAPOCH: i64 = 11017;
61        const DAYS_PER_400Y: i64 = 365 * 400 + 97;
62        const DAYS_PER_100Y: i64 = 365 * 100 + 24;
63        const DAYS_PER_4Y: i64 = 365 * 4 + 1;
64
65        let days = (secs_since_epoch / 86400) as i64 - LEAPOCH;
66        let secs_of_day = secs_since_epoch % 86400;
67
68        let mut qc_cycles = days / DAYS_PER_400Y;
69        let mut remdays = days % DAYS_PER_400Y;
70
71        if remdays < 0 {
72            remdays += DAYS_PER_400Y;
73            qc_cycles -= 1;
74        }
75
76        let mut c_cycles = remdays / DAYS_PER_100Y;
77        if c_cycles == 4 {
78            c_cycles -= 1;
79        }
80        remdays -= c_cycles * DAYS_PER_100Y;
81
82        let mut q_cycles = remdays / DAYS_PER_4Y;
83        if q_cycles == 25 {
84            q_cycles -= 1;
85        }
86        remdays -= q_cycles * DAYS_PER_4Y;
87
88        let mut remyears = remdays / 365;
89        if remyears == 4 {
90            remyears -= 1;
91        }
92        remdays -= remyears * 365;
93
94        let mut year = 2000 + remyears + 4 * q_cycles + 100 * c_cycles + 400 * qc_cycles;
95
96        let months = [31, 30, 31, 30, 31, 31, 30, 31, 30, 31, 31, 29];
97        let mut mon = 0;
98        for mon_len in months.iter() {
99            mon += 1;
100            if remdays < *mon_len {
101                break;
102            }
103            remdays -= *mon_len;
104        }
105        let mday = remdays + 1;
106        let mon = if mon + 2 > 12 {
107            year += 1;
108            mon - 10
109        } else {
110            mon + 2
111        };
112
113        let mut wday = (3 + days) % 7;
114        if wday <= 0 {
115            wday += 7
116        };
117
118        HttpDate {
119            sec: (secs_of_day % 60) as u8,
120            min: ((secs_of_day % 3600) / 60) as u8,
121            hour: (secs_of_day / 3600) as u8,
122            day: mday as u8,
123            mon: mon as u8,
124            year: year as u16,
125            wday: wday as u8,
126        }
127    }
128}
129
130impl From<HttpDate> for SystemTime {
131    fn from(v: HttpDate) -> SystemTime {
132        let leap_years =
133            ((v.year - 1) - 1968) / 4 - ((v.year - 1) - 1900) / 100 + ((v.year - 1) - 1600) / 400;
134        let mut ydays = match v.mon {
135            1 => 0,
136            2 => 31,
137            3 => 59,
138            4 => 90,
139            5 => 120,
140            6 => 151,
141            7 => 181,
142            8 => 212,
143            9 => 243,
144            10 => 273,
145            11 => 304,
146            12 => 334,
147            _ => unreachable!(),
148        } + v.day as u64
149            - 1;
150        if is_leap_year(v.year) && v.mon > 2 {
151            ydays += 1;
152        }
153        let days = (v.year as u64 - 1970) * 365 + leap_years as u64 + ydays;
154        UNIX_EPOCH
155            + Duration::from_secs(
156                v.sec as u64 + v.min as u64 * 60 + v.hour as u64 * 3600 + days * 86400,
157            )
158    }
159}
160
161impl FromStr for HttpDate {
162    type Err = Error;
163
164    fn from_str(s: &str) -> Result<HttpDate, Error> {
165        if !s.is_ascii() {
166            return Err(Error(()));
167        }
168        let x = s.trim().as_bytes();
169        let date = parse_imf_fixdate(x)
170            .or_else(|_| parse_rfc850_date(x))
171            .or_else(|_| parse_asctime(x))?;
172        if !date.is_valid() {
173            return Err(Error(()));
174        }
175        Ok(date)
176    }
177}
178
179impl Display for HttpDate {
180    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
181        let wday = match self.wday {
182            1 => b"Mon",
183            2 => b"Tue",
184            3 => b"Wed",
185            4 => b"Thu",
186            5 => b"Fri",
187            6 => b"Sat",
188            7 => b"Sun",
189            _ => unreachable!(),
190        };
191
192        let mon = match self.mon {
193            1 => b"Jan",
194            2 => b"Feb",
195            3 => b"Mar",
196            4 => b"Apr",
197            5 => b"May",
198            6 => b"Jun",
199            7 => b"Jul",
200            8 => b"Aug",
201            9 => b"Sep",
202            10 => b"Oct",
203            11 => b"Nov",
204            12 => b"Dec",
205            _ => unreachable!(),
206        };
207
208        let mut buf: [u8; 29] = *b"   , 00     0000 00:00:00 GMT";
209        buf[0] = wday[0];
210        buf[1] = wday[1];
211        buf[2] = wday[2];
212        buf[5] = b'0' + (self.day / 10) as u8;
213        buf[6] = b'0' + (self.day % 10) as u8;
214        buf[8] = mon[0];
215        buf[9] = mon[1];
216        buf[10] = mon[2];
217        buf[12] = b'0' + (self.year / 1000) as u8;
218        buf[13] = b'0' + (self.year / 100 % 10) as u8;
219        buf[14] = b'0' + (self.year / 10 % 10) as u8;
220        buf[15] = b'0' + (self.year % 10) as u8;
221        buf[17] = b'0' + (self.hour / 10) as u8;
222        buf[18] = b'0' + (self.hour % 10) as u8;
223        buf[20] = b'0' + (self.min / 10) as u8;
224        buf[21] = b'0' + (self.min % 10) as u8;
225        buf[23] = b'0' + (self.sec / 10) as u8;
226        buf[24] = b'0' + (self.sec % 10) as u8;
227        f.write_str(std::str::from_utf8(&buf[..]).unwrap())
228    }
229}
230
231impl Ord for HttpDate {
232    fn cmp(&self, other: &HttpDate) -> cmp::Ordering {
233        SystemTime::from(*self).cmp(&SystemTime::from(*other))
234    }
235}
236
237impl PartialOrd for HttpDate {
238    fn partial_cmp(&self, other: &HttpDate) -> Option<cmp::Ordering> {
239        Some(self.cmp(other))
240    }
241}
242
243fn toint_1(x: u8) -> Result<u8, Error> {
244    let result = x.wrapping_sub(b'0');
245    if result < 10 {
246        Ok(result)
247    } else {
248        Err(Error(()))
249    }
250}
251
252fn toint_2(s: &[u8]) -> Result<u8, Error> {
253    let high = s[0].wrapping_sub(b'0');
254    let low = s[1].wrapping_sub(b'0');
255
256    if high < 10 && low < 10 {
257        Ok(high * 10 + low)
258    } else {
259        Err(Error(()))
260    }
261}
262
263#[allow(clippy::many_single_char_names)]
264fn toint_4(s: &[u8]) -> Result<u16, Error> {
265    let a = u16::from(s[0].wrapping_sub(b'0'));
266    let b = u16::from(s[1].wrapping_sub(b'0'));
267    let c = u16::from(s[2].wrapping_sub(b'0'));
268    let d = u16::from(s[3].wrapping_sub(b'0'));
269
270    if a < 10 && b < 10 && c < 10 && d < 10 {
271        Ok(a * 1000 + b * 100 + c * 10 + d)
272    } else {
273        Err(Error(()))
274    }
275}
276
277fn parse_imf_fixdate(s: &[u8]) -> Result<HttpDate, Error> {
278    // Example: `Sun, 06 Nov 1994 08:49:37 GMT`
279    if s.len() != 29 || &s[25..] != b" GMT" || s[16] != b' ' || s[19] != b':' || s[22] != b':' {
280        return Err(Error(()));
281    }
282    Ok(HttpDate {
283        sec: toint_2(&s[23..25])?,
284        min: toint_2(&s[20..22])?,
285        hour: toint_2(&s[17..19])?,
286        day: toint_2(&s[5..7])?,
287        mon: match &s[7..12] {
288            b" Jan " => 1,
289            b" Feb " => 2,
290            b" Mar " => 3,
291            b" Apr " => 4,
292            b" May " => 5,
293            b" Jun " => 6,
294            b" Jul " => 7,
295            b" Aug " => 8,
296            b" Sep " => 9,
297            b" Oct " => 10,
298            b" Nov " => 11,
299            b" Dec " => 12,
300            _ => return Err(Error(())),
301        },
302        year: toint_4(&s[12..16])?,
303        wday: match &s[..5] {
304            b"Mon, " => 1,
305            b"Tue, " => 2,
306            b"Wed, " => 3,
307            b"Thu, " => 4,
308            b"Fri, " => 5,
309            b"Sat, " => 6,
310            b"Sun, " => 7,
311            _ => return Err(Error(())),
312        },
313    })
314}
315
316fn parse_rfc850_date(s: &[u8]) -> Result<HttpDate, Error> {
317    // Example: `Sunday, 06-Nov-94 08:49:37 GMT`
318    if s.len() < 23 {
319        return Err(Error(()));
320    }
321
322    fn wday<'a>(s: &'a [u8], wday: u8, name: &'static [u8]) -> Option<(u8, &'a [u8])> {
323        if &s[0..name.len()] == name {
324            return Some((wday, &s[name.len()..]));
325        }
326        None
327    }
328    let (wday, s) = wday(s, 1, b"Monday, ")
329        .or_else(|| wday(s, 2, b"Tuesday, "))
330        .or_else(|| wday(s, 3, b"Wednesday, "))
331        .or_else(|| wday(s, 4, b"Thursday, "))
332        .or_else(|| wday(s, 5, b"Friday, "))
333        .or_else(|| wday(s, 6, b"Saturday, "))
334        .or_else(|| wday(s, 7, b"Sunday, "))
335        .ok_or(Error(()))?;
336    if s.len() != 22 || s[12] != b':' || s[15] != b':' || &s[18..22] != b" GMT" {
337        return Err(Error(()));
338    }
339    let mut year = u16::from(toint_2(&s[7..9])?);
340    if year < 70 {
341        year += 2000;
342    } else {
343        year += 1900;
344    }
345    Ok(HttpDate {
346        sec: toint_2(&s[16..18])?,
347        min: toint_2(&s[13..15])?,
348        hour: toint_2(&s[10..12])?,
349        day: toint_2(&s[0..2])?,
350        mon: match &s[2..7] {
351            b"-Jan-" => 1,
352            b"-Feb-" => 2,
353            b"-Mar-" => 3,
354            b"-Apr-" => 4,
355            b"-May-" => 5,
356            b"-Jun-" => 6,
357            b"-Jul-" => 7,
358            b"-Aug-" => 8,
359            b"-Sep-" => 9,
360            b"-Oct-" => 10,
361            b"-Nov-" => 11,
362            b"-Dec-" => 12,
363            _ => return Err(Error(())),
364        },
365        year,
366        wday,
367    })
368}
369
370fn parse_asctime(s: &[u8]) -> Result<HttpDate, Error> {
371    // Example: `Sun Nov  6 08:49:37 1994`
372    if s.len() != 24 || s[10] != b' ' || s[13] != b':' || s[16] != b':' || s[19] != b' ' {
373        return Err(Error(()));
374    }
375    Ok(HttpDate {
376        sec: toint_2(&s[17..19])?,
377        min: toint_2(&s[14..16])?,
378        hour: toint_2(&s[11..13])?,
379        day: {
380            let x = &s[8..10];
381            {
382                if x[0] == b' ' {
383                    toint_1(x[1])
384                } else {
385                    toint_2(x)
386                }
387            }?
388        },
389        mon: match &s[4..8] {
390            b"Jan " => 1,
391            b"Feb " => 2,
392            b"Mar " => 3,
393            b"Apr " => 4,
394            b"May " => 5,
395            b"Jun " => 6,
396            b"Jul " => 7,
397            b"Aug " => 8,
398            b"Sep " => 9,
399            b"Oct " => 10,
400            b"Nov " => 11,
401            b"Dec " => 12,
402            _ => return Err(Error(())),
403        },
404        year: toint_4(&s[20..24])?,
405        wday: match &s[0..4] {
406            b"Mon " => 1,
407            b"Tue " => 2,
408            b"Wed " => 3,
409            b"Thu " => 4,
410            b"Fri " => 5,
411            b"Sat " => 6,
412            b"Sun " => 7,
413            _ => return Err(Error(())),
414        },
415    })
416}
417
418fn is_leap_year(y: u16) -> bool {
419    y % 4 == 0 && (y % 100 != 0 || y % 400 == 0)
420}
httpdate/date.rs

httpdate/
date.rs
