http/
status.rs

1//! HTTP status codes
2//!
3//! This module contains HTTP-status code related structs an errors. The main
4//! type in this module is `StatusCode` which is not intended to be used through
5//! this module but rather the `http::StatusCode` type.
6//!
7//! # Examples
8//!
9//! ```
10//! use http::StatusCode;
11//!
12//! assert_eq!(StatusCode::from_u16(200).unwrap(), StatusCode::OK);
13//! assert_eq!(StatusCode::NOT_FOUND, 404);
14//! assert!(StatusCode::OK.is_success());
15//! ```
16
17use std::convert::TryFrom;
18use std::error::Error;
19use std::fmt;
20use std::num::NonZeroU16;
21use std::str::FromStr;
22
23/// An HTTP status code (`status-code` in RFC 9110 et al.).
24///
25/// Constants are provided for known status codes, including those in the IANA
26/// [HTTP Status Code Registry](
27/// https://www.iana.org/assignments/http-status-codes/http-status-codes.xhtml).
28///
29/// Status code values in the range 100-999 (inclusive) are supported by this
30/// type. Values in the range 100-599 are semantically classified by the most
31/// significant digit. See [`StatusCode::is_success`], etc. Values above 599
32/// are unclassified but allowed for legacy compatibility, though their use is
33/// discouraged. Applications may interpret such values as protocol errors.
34///
35/// # Examples
36///
37/// ```
38/// use http::StatusCode;
39///
40/// assert_eq!(StatusCode::from_u16(200).unwrap(), StatusCode::OK);
41/// assert_eq!(StatusCode::NOT_FOUND.as_u16(), 404);
42/// assert!(StatusCode::OK.is_success());
43/// ```
44#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
45pub struct StatusCode(NonZeroU16);
46
47/// A possible error value when converting a `StatusCode` from a `u16` or `&str`
48///
49/// This error indicates that the supplied input was not a valid number, was less
50/// than 100, or was greater than 999.
51pub struct InvalidStatusCode {
52    _priv: (),
53}
54
55impl StatusCode {
56    /// Converts a u16 to a status code.
57    ///
58    /// The function validates the correctness of the supplied u16. It must be
59    /// greater or equal to 100 and less than 1000.
60    ///
61    /// # Example
62    ///
63    /// ```
64    /// use http::StatusCode;
65    ///
66    /// let ok = StatusCode::from_u16(200).unwrap();
67    /// assert_eq!(ok, StatusCode::OK);
68    ///
69    /// let err = StatusCode::from_u16(99);
70    /// assert!(err.is_err());
71    /// ```
72    #[inline]
73    pub fn from_u16(src: u16) -> Result<StatusCode, InvalidStatusCode> {
74        if !(100..1000).contains(&src) {
75            return Err(InvalidStatusCode::new());
76        }
77
78        NonZeroU16::new(src)
79            .map(StatusCode)
80            .ok_or_else(InvalidStatusCode::new)
81    }
82
83    /// Converts a &[u8] to a status code
84    pub fn from_bytes(src: &[u8]) -> Result<StatusCode, InvalidStatusCode> {
85        if src.len() != 3 {
86            return Err(InvalidStatusCode::new());
87        }
88
89        let a = src[0].wrapping_sub(b'0') as u16;
90        let b = src[1].wrapping_sub(b'0') as u16;
91        let c = src[2].wrapping_sub(b'0') as u16;
92
93        if a == 0 || a > 9 || b > 9 || c > 9 {
94            return Err(InvalidStatusCode::new());
95        }
96
97        let status = (a * 100) + (b * 10) + c;
98        NonZeroU16::new(status)
99            .map(StatusCode)
100            .ok_or_else(InvalidStatusCode::new)
101    }
102
103    /// Returns the `u16` corresponding to this `StatusCode`.
104    ///
105    /// # Note
106    ///
107    /// This is the same as the `From<StatusCode>` implementation, but
108    /// included as an inherent method because that implementation doesn't
109    /// appear in rustdocs, as well as a way to force the type instead of
110    /// relying on inference.
111    ///
112    /// # Example
113    ///
114    /// ```
115    /// let status = http::StatusCode::OK;
116    /// assert_eq!(status.as_u16(), 200);
117    /// ```
118    #[inline]
119    pub const fn as_u16(&self) -> u16 {
120        (*self).0.get()
121    }
122
123    /// Returns a &str representation of the `StatusCode`
124    ///
125    /// The return value only includes a numerical representation of the
126    /// status code. The canonical reason is not included.
127    ///
128    /// # Example
129    ///
130    /// ```
131    /// let status = http::StatusCode::OK;
132    /// assert_eq!(status.as_str(), "200");
133    /// ```
134    #[inline]
135    pub fn as_str(&self) -> &str {
136        let offset = (self.0.get() - 100) as usize;
137        let offset = offset * 3;
138
139        // Invariant: self has checked range [100, 999] and CODE_DIGITS is
140        // ASCII-only, of length 900 * 3 = 2700 bytes
141
142        #[cfg(debug_assertions)]
143        {
144            &CODE_DIGITS[offset..offset + 3]
145        }
146
147        #[cfg(not(debug_assertions))]
148        unsafe {
149            CODE_DIGITS.get_unchecked(offset..offset + 3)
150        }
151    }
152
153    /// Get the standardised `reason-phrase` for this status code.
154    ///
155    /// This is mostly here for servers writing responses, but could potentially have application
156    /// at other times.
157    ///
158    /// The reason phrase is defined as being exclusively for human readers. You should avoid
159    /// deriving any meaning from it at all costs.
160    ///
161    /// Bear in mind also that in HTTP/2.0 and HTTP/3.0 the reason phrase is abolished from
162    /// transmission, and so this canonical reason phrase really is the only reason phrase you’ll
163    /// find.
164    ///
165    /// # Example
166    ///
167    /// ```
168    /// let status = http::StatusCode::OK;
169    /// assert_eq!(status.canonical_reason(), Some("OK"));
170    /// ```
171    pub fn canonical_reason(&self) -> Option<&'static str> {
172        canonical_reason(self.0.get())
173    }
174
175    /// Check if status is within 100-199.
176    #[inline]
177    pub fn is_informational(&self) -> bool {
178        200 > self.0.get() && self.0.get() >= 100
179    }
180
181    /// Check if status is within 200-299.
182    #[inline]
183    pub fn is_success(&self) -> bool {
184        300 > self.0.get() && self.0.get() >= 200
185    }
186
187    /// Check if status is within 300-399.
188    #[inline]
189    pub fn is_redirection(&self) -> bool {
190        400 > self.0.get() && self.0.get() >= 300
191    }
192
193    /// Check if status is within 400-499.
194    #[inline]
195    pub fn is_client_error(&self) -> bool {
196        500 > self.0.get() && self.0.get() >= 400
197    }
198
199    /// Check if status is within 500-599.
200    #[inline]
201    pub fn is_server_error(&self) -> bool {
202        600 > self.0.get() && self.0.get() >= 500
203    }
204}
205
206impl fmt::Debug for StatusCode {
207    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
208        fmt::Debug::fmt(&self.0, f)
209    }
210}
211
212/// Formats the status code, *including* the canonical reason.
213///
214/// # Example
215///
216/// ```
217/// # use http::StatusCode;
218/// assert_eq!(format!("{}", StatusCode::OK), "200 OK");
219/// ```
220impl fmt::Display for StatusCode {
221    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
222        write!(
223            f,
224            "{} {}",
225            u16::from(*self),
226            self.canonical_reason().unwrap_or("<unknown status code>")
227        )
228    }
229}
230
231impl Default for StatusCode {
232    #[inline]
233    fn default() -> StatusCode {
234        StatusCode::OK
235    }
236}
237
238impl PartialEq<u16> for StatusCode {
239    #[inline]
240    fn eq(&self, other: &u16) -> bool {
241        self.as_u16() == *other
242    }
243}
244
245impl PartialEq<StatusCode> for u16 {
246    #[inline]
247    fn eq(&self, other: &StatusCode) -> bool {
248        *self == other.as_u16()
249    }
250}
251
252impl From<StatusCode> for u16 {
253    #[inline]
254    fn from(status: StatusCode) -> u16 {
255        status.0.get()
256    }
257}
258
259impl FromStr for StatusCode {
260    type Err = InvalidStatusCode;
261
262    fn from_str(s: &str) -> Result<StatusCode, InvalidStatusCode> {
263        StatusCode::from_bytes(s.as_ref())
264    }
265}
266
267impl<'a> From<&'a StatusCode> for StatusCode {
268    #[inline]
269    fn from(t: &'a StatusCode) -> Self {
270        t.to_owned()
271    }
272}
273
274impl<'a> TryFrom<&'a [u8]> for StatusCode {
275    type Error = InvalidStatusCode;
276
277    #[inline]
278    fn try_from(t: &'a [u8]) -> Result<Self, Self::Error> {
279        StatusCode::from_bytes(t)
280    }
281}
282
283impl<'a> TryFrom<&'a str> for StatusCode {
284    type Error = InvalidStatusCode;
285
286    #[inline]
287    fn try_from(t: &'a str) -> Result<Self, Self::Error> {
288        t.parse()
289    }
290}
291
292impl TryFrom<u16> for StatusCode {
293    type Error = InvalidStatusCode;
294
295    #[inline]
296    fn try_from(t: u16) -> Result<Self, Self::Error> {
297        StatusCode::from_u16(t)
298    }
299}
300
301macro_rules! status_codes {
302    (
303        $(
304            $(#[$docs:meta])*
305            ($num:expr, $konst:ident, $phrase:expr);
306        )+
307    ) => {
308        impl StatusCode {
309        $(
310            $(#[$docs])*
311            pub const $konst: StatusCode = StatusCode(unsafe { NonZeroU16::new_unchecked($num) });
312        )+
313
314        }
315
316        fn canonical_reason(num: u16) -> Option<&'static str> {
317            match num {
318                $(
319                $num => Some($phrase),
320                )+
321                _ => None
322            }
323        }
324    }
325}
326
327status_codes! {
328    /// 100 Continue
329    /// [[RFC9110, Section 15.2.1](https://datatracker.ietf.org/doc/html/rfc9110#section-15.2.1)]
330    (100, CONTINUE, "Continue");
331    /// 101 Switching Protocols
332    /// [[RFC9110, Section 15.2.2](https://datatracker.ietf.org/doc/html/rfc9110#section-15.2.2)]
333    (101, SWITCHING_PROTOCOLS, "Switching Protocols");
334    /// 102 Processing
335    /// [[RFC2518, Section 10.1](https://datatracker.ietf.org/doc/html/rfc2518#section-10.1)]
336    (102, PROCESSING, "Processing");
337
338    /// 200 OK
339    /// [[RFC9110, Section 15.3.1](https://datatracker.ietf.org/doc/html/rfc9110#section-15.3.1)]
340    (200, OK, "OK");
341    /// 201 Created
342    /// [[RFC9110, Section 15.3.2](https://datatracker.ietf.org/doc/html/rfc9110#section-15.3.2)]
343    (201, CREATED, "Created");
344    /// 202 Accepted
345    /// [[RFC9110, Section 15.3.3](https://datatracker.ietf.org/doc/html/rfc9110#section-15.3.3)]
346    (202, ACCEPTED, "Accepted");
347    /// 203 Non-Authoritative Information
348    /// [[RFC9110, Section 15.3.4](https://datatracker.ietf.org/doc/html/rfc9110#section-15.3.4)]
349    (203, NON_AUTHORITATIVE_INFORMATION, "Non Authoritative Information");
350    /// 204 No Content
351    /// [[RFC9110, Section 15.3.5](https://datatracker.ietf.org/doc/html/rfc9110#section-15.3.5)]
352    (204, NO_CONTENT, "No Content");
353    /// 205 Reset Content
354    /// [[RFC9110, Section 15.3.6](https://datatracker.ietf.org/doc/html/rfc9110#section-15.3.6)]
355    (205, RESET_CONTENT, "Reset Content");
356    /// 206 Partial Content
357    /// [[RFC9110, Section 15.3.7](https://datatracker.ietf.org/doc/html/rfc9110#section-15.3.7)]
358    (206, PARTIAL_CONTENT, "Partial Content");
359    /// 207 Multi-Status
360    /// [[RFC4918, Section 11.1](https://datatracker.ietf.org/doc/html/rfc4918#section-11.1)]
361    (207, MULTI_STATUS, "Multi-Status");
362    /// 208 Already Reported
363    /// [[RFC5842, Section 7.1](https://datatracker.ietf.org/doc/html/rfc5842#section-7.1)]
364    (208, ALREADY_REPORTED, "Already Reported");
365
366    /// 226 IM Used
367    /// [[RFC3229, Section 10.4.1](https://datatracker.ietf.org/doc/html/rfc3229#section-10.4.1)]
368    (226, IM_USED, "IM Used");
369
370    /// 300 Multiple Choices
371    /// [[RFC9110, Section 15.4.1](https://datatracker.ietf.org/doc/html/rfc9110#section-15.4.1)]
372    (300, MULTIPLE_CHOICES, "Multiple Choices");
373    /// 301 Moved Permanently
374    /// [[RFC9110, Section 15.4.2](https://datatracker.ietf.org/doc/html/rfc9110#section-15.4.2)]
375    (301, MOVED_PERMANENTLY, "Moved Permanently");
376    /// 302 Found
377    /// [[RFC9110, Section 15.4.3](https://datatracker.ietf.org/doc/html/rfc9110#section-15.4.3)]
378    (302, FOUND, "Found");
379    /// 303 See Other
380    /// [[RFC9110, Section 15.4.4](https://datatracker.ietf.org/doc/html/rfc9110#section-15.4.4)]
381    (303, SEE_OTHER, "See Other");
382    /// 304 Not Modified
383    /// [[RFC9110, Section 15.4.5](https://datatracker.ietf.org/doc/html/rfc9110#section-15.4.5)]
384    (304, NOT_MODIFIED, "Not Modified");
385    /// 305 Use Proxy
386    /// [[RFC9110, Section 15.4.6](https://datatracker.ietf.org/doc/html/rfc9110#section-15.4.6)]
387    (305, USE_PROXY, "Use Proxy");
388    /// 307 Temporary Redirect
389    /// [[RFC9110, Section 15.4.7](https://datatracker.ietf.org/doc/html/rfc9110#section-15.4.7)]
390    (307, TEMPORARY_REDIRECT, "Temporary Redirect");
391    /// 308 Permanent Redirect
392    /// [[RFC9110, Section 15.4.8](https://datatracker.ietf.org/doc/html/rfc9110#section-15.4.8)]
393    (308, PERMANENT_REDIRECT, "Permanent Redirect");
394
395    /// 400 Bad Request
396    /// [[RFC9110, Section 15.5.1](https://datatracker.ietf.org/doc/html/rfc9110#section-15.5.1)]
397    (400, BAD_REQUEST, "Bad Request");
398    /// 401 Unauthorized
399    /// [[RFC9110, Section 15.5.2](https://datatracker.ietf.org/doc/html/rfc9110#section-15.5.2)]
400    (401, UNAUTHORIZED, "Unauthorized");
401    /// 402 Payment Required
402    /// [[RFC9110, Section 15.5.3](https://datatracker.ietf.org/doc/html/rfc9110#section-15.5.3)]
403    (402, PAYMENT_REQUIRED, "Payment Required");
404    /// 403 Forbidden
405    /// [[RFC9110, Section 15.5.4](https://datatracker.ietf.org/doc/html/rfc9110#section-15.5.4)]
406    (403, FORBIDDEN, "Forbidden");
407    /// 404 Not Found
408    /// [[RFC9110, Section 15.5.5](https://datatracker.ietf.org/doc/html/rfc9110#section-15.5.5)]
409    (404, NOT_FOUND, "Not Found");
410    /// 405 Method Not Allowed
411    /// [[RFC9110, Section 15.5.6](https://datatracker.ietf.org/doc/html/rfc9110#section-15.5.6)]
412    (405, METHOD_NOT_ALLOWED, "Method Not Allowed");
413    /// 406 Not Acceptable
414    /// [[RFC9110, Section 15.5.7](https://datatracker.ietf.org/doc/html/rfc9110#section-15.5.7)]
415    (406, NOT_ACCEPTABLE, "Not Acceptable");
416    /// 407 Proxy Authentication Required
417    /// [[RFC9110, Section 15.5.8](https://datatracker.ietf.org/doc/html/rfc9110#section-15.5.8)]
418    (407, PROXY_AUTHENTICATION_REQUIRED, "Proxy Authentication Required");
419    /// 408 Request Timeout
420    /// [[RFC9110, Section 15.5.9](https://datatracker.ietf.org/doc/html/rfc9110#section-15.5.9)]
421    (408, REQUEST_TIMEOUT, "Request Timeout");
422    /// 409 Conflict
423    /// [[RFC9110, Section 15.5.10](https://datatracker.ietf.org/doc/html/rfc9110#section-15.5.10)]
424    (409, CONFLICT, "Conflict");
425    /// 410 Gone
426    /// [[RFC9110, Section 15.5.11](https://datatracker.ietf.org/doc/html/rfc9110#section-15.5.11)]
427    (410, GONE, "Gone");
428    /// 411 Length Required
429    /// [[RFC9110, Section 15.5.12](https://datatracker.ietf.org/doc/html/rfc9110#section-15.5.12)]
430    (411, LENGTH_REQUIRED, "Length Required");
431    /// 412 Precondition Failed
432    /// [[RFC9110, Section 15.5.13](https://datatracker.ietf.org/doc/html/rfc9110#section-15.5.13)]
433    (412, PRECONDITION_FAILED, "Precondition Failed");
434    /// 413 Payload Too Large
435    /// [[RFC9110, Section 15.5.14](https://datatracker.ietf.org/doc/html/rfc9110#section-15.5.14)]
436    (413, PAYLOAD_TOO_LARGE, "Payload Too Large");
437    /// 414 URI Too Long
438    /// [[RFC9110, Section 15.5.15](https://datatracker.ietf.org/doc/html/rfc9110#section-15.5.15)]
439    (414, URI_TOO_LONG, "URI Too Long");
440    /// 415 Unsupported Media Type
441    /// [[RFC9110, Section 15.5.16](https://datatracker.ietf.org/doc/html/rfc9110#section-15.5.16)]
442    (415, UNSUPPORTED_MEDIA_TYPE, "Unsupported Media Type");
443    /// 416 Range Not Satisfiable
444    /// [[RFC9110, Section 15.5.17](https://datatracker.ietf.org/doc/html/rfc9110#section-15.5.17)]
445    (416, RANGE_NOT_SATISFIABLE, "Range Not Satisfiable");
446    /// 417 Expectation Failed
447    /// [[RFC9110, Section 15.5.18](https://datatracker.ietf.org/doc/html/rfc9110#section-15.5.18)]
448    (417, EXPECTATION_FAILED, "Expectation Failed");
449    /// 418 I'm a teapot
450    /// [curiously not registered by IANA but [RFC2324, Section 2.3.2](https://datatracker.ietf.org/doc/html/rfc2324#section-2.3.2)]
451    (418, IM_A_TEAPOT, "I'm a teapot");
452
453    /// 421 Misdirected Request
454    /// [[RFC9110, Section 15.5.20](https://datatracker.ietf.org/doc/html/rfc9110#section-15.5.20)]
455    (421, MISDIRECTED_REQUEST, "Misdirected Request");
456    /// 422 Unprocessable Entity
457    /// [[RFC9110, Section 15.5.21](https://datatracker.ietf.org/doc/html/rfc9110#section-15.5.21)]
458    (422, UNPROCESSABLE_ENTITY, "Unprocessable Entity");
459    /// 423 Locked
460    /// [[RFC4918, Section 11.3](https://datatracker.ietf.org/doc/html/rfc4918#section-11.3)]
461    (423, LOCKED, "Locked");
462    /// 424 Failed Dependency
463    /// [[RFC4918, Section 11.4](https://tools.ietf.org/html/rfc4918#section-11.4)]
464    (424, FAILED_DEPENDENCY, "Failed Dependency");
465
466    /// 425 Too early
467    /// [[RFC8470, Section 5.2](https://httpwg.org/specs/rfc8470.html#status)]
468    (425, TOO_EARLY, "Too Early");
469
470    /// 426 Upgrade Required
471    /// [[RFC9110, Section 15.5.22](https://datatracker.ietf.org/doc/html/rfc9110#section-15.5.22)]
472    (426, UPGRADE_REQUIRED, "Upgrade Required");
473
474    /// 428 Precondition Required
475    /// [[RFC6585, Section 3](https://datatracker.ietf.org/doc/html/rfc6585#section-3)]
476    (428, PRECONDITION_REQUIRED, "Precondition Required");
477    /// 429 Too Many Requests
478    /// [[RFC6585, Section 4](https://datatracker.ietf.org/doc/html/rfc6585#section-4)]
479    (429, TOO_MANY_REQUESTS, "Too Many Requests");
480
481    /// 431 Request Header Fields Too Large
482    /// [[RFC6585, Section 5](https://datatracker.ietf.org/doc/html/rfc6585#section-5)]
483    (431, REQUEST_HEADER_FIELDS_TOO_LARGE, "Request Header Fields Too Large");
484
485    /// 451 Unavailable For Legal Reasons
486    /// [[RFC7725, Section 3](https://tools.ietf.org/html/rfc7725#section-3)]
487    (451, UNAVAILABLE_FOR_LEGAL_REASONS, "Unavailable For Legal Reasons");
488
489    /// 500 Internal Server Error
490    /// [[RFC9110, Section 15.6.1](https://datatracker.ietf.org/doc/html/rfc9110#section-15.6.1)]
491    (500, INTERNAL_SERVER_ERROR, "Internal Server Error");
492    /// 501 Not Implemented
493    /// [[RFC9110, Section 15.6.2](https://datatracker.ietf.org/doc/html/rfc9110#section-15.6.2)]
494    (501, NOT_IMPLEMENTED, "Not Implemented");
495    /// 502 Bad Gateway
496    /// [[RFC9110, Section 15.6.3](https://datatracker.ietf.org/doc/html/rfc9110#section-15.6.3)]
497    (502, BAD_GATEWAY, "Bad Gateway");
498    /// 503 Service Unavailable
499    /// [[RFC9110, Section 15.6.4](https://datatracker.ietf.org/doc/html/rfc9110#section-15.6.4)]
500    (503, SERVICE_UNAVAILABLE, "Service Unavailable");
501    /// 504 Gateway Timeout
502    /// [[RFC9110, Section 15.6.5](https://datatracker.ietf.org/doc/html/rfc9110#section-15.6.5)]
503    (504, GATEWAY_TIMEOUT, "Gateway Timeout");
504    /// 505 HTTP Version Not Supported
505    /// [[RFC9110, Section 15.6.6](https://datatracker.ietf.org/doc/html/rfc9110#section-15.6.6)]
506    (505, HTTP_VERSION_NOT_SUPPORTED, "HTTP Version Not Supported");
507    /// 506 Variant Also Negotiates
508    /// [[RFC2295, Section 8.1](https://datatracker.ietf.org/doc/html/rfc2295#section-8.1)]
509    (506, VARIANT_ALSO_NEGOTIATES, "Variant Also Negotiates");
510    /// 507 Insufficient Storage
511    /// [[RFC4918, Section 11.5](https://datatracker.ietf.org/doc/html/rfc4918#section-11.5)]
512    (507, INSUFFICIENT_STORAGE, "Insufficient Storage");
513    /// 508 Loop Detected
514    /// [[RFC5842, Section 7.2](https://datatracker.ietf.org/doc/html/rfc5842#section-7.2)]
515    (508, LOOP_DETECTED, "Loop Detected");
516
517    /// 510 Not Extended
518    /// [[RFC2774, Section 7](https://datatracker.ietf.org/doc/html/rfc2774#section-7)]
519    (510, NOT_EXTENDED, "Not Extended");
520    /// 511 Network Authentication Required
521    /// [[RFC6585, Section 6](https://datatracker.ietf.org/doc/html/rfc6585#section-6)]
522    (511, NETWORK_AUTHENTICATION_REQUIRED, "Network Authentication Required");
523}
524
525impl InvalidStatusCode {
526    fn new() -> InvalidStatusCode {
527        InvalidStatusCode { _priv: () }
528    }
529}
530
531impl fmt::Debug for InvalidStatusCode {
532    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
533        f.debug_struct("InvalidStatusCode")
534            // skip _priv noise
535            .finish()
536    }
537}
538
539impl fmt::Display for InvalidStatusCode {
540    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
541        f.write_str("invalid status code")
542    }
543}
544
545impl Error for InvalidStatusCode {}
546
547// A string of packed 3-ASCII-digit status code values for the supported range
548// of [100, 999] (900 codes, 2700 bytes).
549const CODE_DIGITS: &str = "\
550100101102103104105106107108109110111112113114115116117118119\
551120121122123124125126127128129130131132133134135136137138139\
552140141142143144145146147148149150151152153154155156157158159\
553160161162163164165166167168169170171172173174175176177178179\
554180181182183184185186187188189190191192193194195196197198199\
555200201202203204205206207208209210211212213214215216217218219\
556220221222223224225226227228229230231232233234235236237238239\
557240241242243244245246247248249250251252253254255256257258259\
558260261262263264265266267268269270271272273274275276277278279\
559280281282283284285286287288289290291292293294295296297298299\
560300301302303304305306307308309310311312313314315316317318319\
561320321322323324325326327328329330331332333334335336337338339\
562340341342343344345346347348349350351352353354355356357358359\
563360361362363364365366367368369370371372373374375376377378379\
564380381382383384385386387388389390391392393394395396397398399\
565400401402403404405406407408409410411412413414415416417418419\
566420421422423424425426427428429430431432433434435436437438439\
567440441442443444445446447448449450451452453454455456457458459\
568460461462463464465466467468469470471472473474475476477478479\
569480481482483484485486487488489490491492493494495496497498499\
570500501502503504505506507508509510511512513514515516517518519\
571520521522523524525526527528529530531532533534535536537538539\
572540541542543544545546547548549550551552553554555556557558559\
573560561562563564565566567568569570571572573574575576577578579\
574580581582583584585586587588589590591592593594595596597598599\
575600601602603604605606607608609610611612613614615616617618619\
576620621622623624625626627628629630631632633634635636637638639\
577640641642643644645646647648649650651652653654655656657658659\
578660661662663664665666667668669670671672673674675676677678679\
579680681682683684685686687688689690691692693694695696697698699\
580700701702703704705706707708709710711712713714715716717718719\
581720721722723724725726727728729730731732733734735736737738739\
582740741742743744745746747748749750751752753754755756757758759\
583760761762763764765766767768769770771772773774775776777778779\
584780781782783784785786787788789790791792793794795796797798799\
585800801802803804805806807808809810811812813814815816817818819\
586820821822823824825826827828829830831832833834835836837838839\
587840841842843844845846847848849850851852853854855856857858859\
588860861862863864865866867868869870871872873874875876877878879\
589880881882883884885886887888889890891892893894895896897898899\
590900901902903904905906907908909910911912913914915916917918919\
591920921922923924925926927928929930931932933934935936937938939\
592940941942943944945946947948949950951952953954955956957958959\
593960961962963964965966967968969970971972973974975976977978979\
594980981982983984985986987988989990991992993994995996997998999";