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9346a6ac | 1 | // Copyright 2013-2015 The Rust Project Developers. See the COPYRIGHT |
1a4d82fc JJ |
2 | // file at the top-level directory of this distribution and at |
3 | // http://rust-lang.org/COPYRIGHT. | |
4 | // | |
5 | // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or | |
6 | // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license | |
7 | // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your | |
8 | // option. This file may not be copied, modified, or distributed | |
9 | // except according to those terms. | |
10 | ||
54a0048b | 11 | //! Utilities for formatting and printing strings. |
1a4d82fc | 12 | |
85aaf69f | 13 | #![stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 14 | |
476ff2be | 15 | use cell::{UnsafeCell, Cell, RefCell, Ref, RefMut}; |
9346a6ac | 16 | use marker::PhantomData; |
1a4d82fc | 17 | use mem; |
d9579d0f | 18 | use num::flt2dec; |
9346a6ac | 19 | use ops::Deref; |
1a4d82fc | 20 | use result; |
1a4d82fc | 21 | use slice; |
9346a6ac | 22 | use str; |
54a0048b SL |
23 | |
24 | #[unstable(feature = "fmt_flags_align", issue = "27726")] | |
25 | /// Possible alignments returned by `Formatter::align` | |
26 | #[derive(Debug)] | |
27 | pub enum Alignment { | |
28 | /// Indication that contents should be left-aligned. | |
29 | Left, | |
30 | /// Indication that contents should be right-aligned. | |
31 | Right, | |
32 | /// Indication that contents should be center-aligned. | |
33 | Center, | |
34 | /// No alignment was requested. | |
35 | Unknown, | |
36 | } | |
37 | ||
92a42be0 | 38 | #[stable(feature = "debug_builders", since = "1.2.0")] |
c34b1796 AL |
39 | pub use self::builders::{DebugStruct, DebugTuple, DebugSet, DebugList, DebugMap}; |
40 | ||
1a4d82fc | 41 | mod num; |
c34b1796 | 42 | mod builders; |
1a4d82fc | 43 | |
e9174d1e SL |
44 | #[unstable(feature = "fmt_internals", reason = "internal to format_args!", |
45 | issue = "0")] | |
85aaf69f SL |
46 | #[doc(hidden)] |
47 | pub mod rt { | |
48 | pub mod v1; | |
49 | } | |
50 | ||
51 | #[stable(feature = "rust1", since = "1.0.0")] | |
1a4d82fc JJ |
52 | /// The type returned by formatter methods. |
53 | pub type Result = result::Result<(), Error>; | |
54 | ||
55 | /// The error type which is returned from formatting a message into a stream. | |
56 | /// | |
57 | /// This type does not support transmission of an error other than that an error | |
58 | /// occurred. Any extra information must be arranged to be transmitted through | |
59 | /// some other means. | |
85aaf69f | 60 | #[stable(feature = "rust1", since = "1.0.0")] |
a7813a04 | 61 | #[derive(Copy, Clone, Debug, Default, Eq, Hash, Ord, PartialEq, PartialOrd)] |
1a4d82fc JJ |
62 | pub struct Error; |
63 | ||
64 | /// A collection of methods that are required to format a message into a stream. | |
65 | /// | |
66 | /// This trait is the type which this modules requires when formatting | |
85aaf69f | 67 | /// information. This is similar to the standard library's `io::Write` trait, |
1a4d82fc JJ |
68 | /// but it is only intended for use in libcore. |
69 | /// | |
70 | /// This trait should generally not be implemented by consumers of the standard | |
85aaf69f SL |
71 | /// library. The `write!` macro accepts an instance of `io::Write`, and the |
72 | /// `io::Write` trait is favored over implementing this trait. | |
73 | #[stable(feature = "rust1", since = "1.0.0")] | |
74 | pub trait Write { | |
1a4d82fc JJ |
75 | /// Writes a slice of bytes into this writer, returning whether the write |
76 | /// succeeded. | |
77 | /// | |
78 | /// This method can only succeed if the entire byte slice was successfully | |
79 | /// written, and this method will not return until all data has been | |
80 | /// written or an error occurs. | |
81 | /// | |
82 | /// # Errors | |
83 | /// | |
62682a34 | 84 | /// This function will return an instance of `Error` on error. |
85aaf69f | 85 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
86 | fn write_str(&mut self, s: &str) -> Result; |
87 | ||
d9579d0f AL |
88 | /// Writes a `char` into this writer, returning whether the write succeeded. |
89 | /// | |
90 | /// A single `char` may be encoded as more than one byte. | |
91 | /// This method can only succeed if the entire byte sequence was successfully | |
92 | /// written, and this method will not return until all data has been | |
93 | /// written or an error occurs. | |
94 | /// | |
95 | /// # Errors | |
96 | /// | |
62682a34 | 97 | /// This function will return an instance of `Error` on error. |
d9579d0f AL |
98 | #[stable(feature = "fmt_write_char", since = "1.1.0")] |
99 | fn write_char(&mut self, c: char) -> Result { | |
c30ab7b3 | 100 | self.write_str(c.encode_utf8(&mut [0; 4])) |
d9579d0f AL |
101 | } |
102 | ||
b039eaaf | 103 | /// Glue for usage of the `write!` macro with implementors of this trait. |
1a4d82fc JJ |
104 | /// |
105 | /// This method should generally not be invoked manually, but rather through | |
106 | /// the `write!` macro itself. | |
85aaf69f | 107 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
108 | fn write_fmt(&mut self, args: Arguments) -> Result { |
109 | // This Adapter is needed to allow `self` (of type `&mut | |
85aaf69f | 110 | // Self`) to be cast to a Write (below) without |
1a4d82fc JJ |
111 | // requiring a `Sized` bound. |
112 | struct Adapter<'a,T: ?Sized +'a>(&'a mut T); | |
113 | ||
85aaf69f SL |
114 | impl<'a, T: ?Sized> Write for Adapter<'a, T> |
115 | where T: Write | |
1a4d82fc JJ |
116 | { |
117 | fn write_str(&mut self, s: &str) -> Result { | |
118 | self.0.write_str(s) | |
119 | } | |
120 | ||
7453a54e SL |
121 | fn write_char(&mut self, c: char) -> Result { |
122 | self.0.write_char(c) | |
123 | } | |
124 | ||
1a4d82fc JJ |
125 | fn write_fmt(&mut self, args: Arguments) -> Result { |
126 | self.0.write_fmt(args) | |
127 | } | |
128 | } | |
129 | ||
130 | write(&mut Adapter(self), args) | |
131 | } | |
132 | } | |
133 | ||
e9174d1e SL |
134 | #[stable(feature = "fmt_write_blanket_impl", since = "1.4.0")] |
135 | impl<'a, W: Write + ?Sized> Write for &'a mut W { | |
136 | fn write_str(&mut self, s: &str) -> Result { | |
137 | (**self).write_str(s) | |
138 | } | |
139 | ||
140 | fn write_char(&mut self, c: char) -> Result { | |
141 | (**self).write_char(c) | |
142 | } | |
143 | ||
144 | fn write_fmt(&mut self, args: Arguments) -> Result { | |
145 | (**self).write_fmt(args) | |
146 | } | |
147 | } | |
148 | ||
1a4d82fc JJ |
149 | /// A struct to represent both where to emit formatting strings to and how they |
150 | /// should be formatted. A mutable version of this is passed to all formatting | |
151 | /// traits. | |
54a0048b | 152 | #[allow(missing_debug_implementations)] |
85aaf69f | 153 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 154 | pub struct Formatter<'a> { |
c34b1796 | 155 | flags: u32, |
1a4d82fc | 156 | fill: char, |
85aaf69f | 157 | align: rt::v1::Alignment, |
c34b1796 AL |
158 | width: Option<usize>, |
159 | precision: Option<usize>, | |
1a4d82fc | 160 | |
85aaf69f SL |
161 | buf: &'a mut (Write+'a), |
162 | curarg: slice::Iter<'a, ArgumentV1<'a>>, | |
163 | args: &'a [ArgumentV1<'a>], | |
1a4d82fc JJ |
164 | } |
165 | ||
166 | // NB. Argument is essentially an optimized partially applied formatting function, | |
167 | // equivalent to `exists T.(&T, fn(&T, &mut Formatter) -> Result`. | |
168 | ||
476ff2be SL |
169 | struct Void { |
170 | _priv: (), | |
171 | } | |
1a4d82fc JJ |
172 | |
173 | /// This struct represents the generic "argument" which is taken by the Xprintf | |
174 | /// family of functions. It contains a function to format the given value. At | |
175 | /// compile time it is ensured that the function and the value have the correct | |
176 | /// types, and then this struct is used to canonicalize arguments to one type. | |
1a4d82fc | 177 | #[derive(Copy)] |
54a0048b | 178 | #[allow(missing_debug_implementations)] |
e9174d1e SL |
179 | #[unstable(feature = "fmt_internals", reason = "internal to format_args!", |
180 | issue = "0")] | |
85aaf69f SL |
181 | #[doc(hidden)] |
182 | pub struct ArgumentV1<'a> { | |
1a4d82fc JJ |
183 | value: &'a Void, |
184 | formatter: fn(&Void, &mut Formatter) -> Result, | |
185 | } | |
186 | ||
92a42be0 SL |
187 | #[unstable(feature = "fmt_internals", reason = "internal to format_args!", |
188 | issue = "0")] | |
c34b1796 AL |
189 | impl<'a> Clone for ArgumentV1<'a> { |
190 | fn clone(&self) -> ArgumentV1<'a> { | |
191 | *self | |
192 | } | |
193 | } | |
194 | ||
85aaf69f | 195 | impl<'a> ArgumentV1<'a> { |
1a4d82fc | 196 | #[inline(never)] |
c34b1796 | 197 | fn show_usize(x: &usize, f: &mut Formatter) -> Result { |
85aaf69f | 198 | Display::fmt(x, f) |
1a4d82fc JJ |
199 | } |
200 | ||
85aaf69f | 201 | #[doc(hidden)] |
e9174d1e SL |
202 | #[unstable(feature = "fmt_internals", reason = "internal to format_args!", |
203 | issue = "0")] | |
85aaf69f SL |
204 | pub fn new<'b, T>(x: &'b T, |
205 | f: fn(&T, &mut Formatter) -> Result) -> ArgumentV1<'b> { | |
1a4d82fc | 206 | unsafe { |
85aaf69f | 207 | ArgumentV1 { |
1a4d82fc JJ |
208 | formatter: mem::transmute(f), |
209 | value: mem::transmute(x) | |
210 | } | |
211 | } | |
212 | } | |
213 | ||
85aaf69f | 214 | #[doc(hidden)] |
e9174d1e SL |
215 | #[unstable(feature = "fmt_internals", reason = "internal to format_args!", |
216 | issue = "0")] | |
c34b1796 AL |
217 | pub fn from_usize(x: &usize) -> ArgumentV1 { |
218 | ArgumentV1::new(x, ArgumentV1::show_usize) | |
1a4d82fc JJ |
219 | } |
220 | ||
c34b1796 AL |
221 | fn as_usize(&self) -> Option<usize> { |
222 | if self.formatter as usize == ArgumentV1::show_usize as usize { | |
223 | Some(unsafe { *(self.value as *const _ as *const usize) }) | |
1a4d82fc JJ |
224 | } else { |
225 | None | |
226 | } | |
227 | } | |
228 | } | |
229 | ||
85aaf69f | 230 | // flags available in the v1 format of format_args |
c34b1796 | 231 | #[derive(Copy, Clone)] |
85aaf69f SL |
232 | #[allow(dead_code)] // SignMinus isn't currently used |
233 | enum FlagV1 { SignPlus, SignMinus, Alternate, SignAwareZeroPad, } | |
234 | ||
1a4d82fc JJ |
235 | impl<'a> Arguments<'a> { |
236 | /// When using the format_args!() macro, this function is used to generate the | |
237 | /// Arguments structure. | |
238 | #[doc(hidden)] #[inline] | |
e9174d1e SL |
239 | #[unstable(feature = "fmt_internals", reason = "internal to format_args!", |
240 | issue = "0")] | |
85aaf69f SL |
241 | pub fn new_v1(pieces: &'a [&'a str], |
242 | args: &'a [ArgumentV1<'a>]) -> Arguments<'a> { | |
1a4d82fc JJ |
243 | Arguments { |
244 | pieces: pieces, | |
245 | fmt: None, | |
246 | args: args | |
247 | } | |
248 | } | |
249 | ||
250 | /// This function is used to specify nonstandard formatting parameters. | |
251 | /// The `pieces` array must be at least as long as `fmt` to construct | |
252 | /// a valid Arguments structure. Also, any `Count` within `fmt` that is | |
253 | /// `CountIsParam` or `CountIsNextParam` has to point to an argument | |
c34b1796 | 254 | /// created with `argumentusize`. However, failing to do so doesn't cause |
1a4d82fc JJ |
255 | /// unsafety, but will ignore invalid . |
256 | #[doc(hidden)] #[inline] | |
e9174d1e SL |
257 | #[unstable(feature = "fmt_internals", reason = "internal to format_args!", |
258 | issue = "0")] | |
85aaf69f SL |
259 | pub fn new_v1_formatted(pieces: &'a [&'a str], |
260 | args: &'a [ArgumentV1<'a>], | |
261 | fmt: &'a [rt::v1::Argument]) -> Arguments<'a> { | |
1a4d82fc JJ |
262 | Arguments { |
263 | pieces: pieces, | |
264 | fmt: Some(fmt), | |
265 | args: args | |
266 | } | |
267 | } | |
268 | } | |
269 | ||
270 | /// This structure represents a safely precompiled version of a format string | |
271 | /// and its arguments. This cannot be generated at runtime because it cannot | |
272 | /// safely be done so, so no constructors are given and the fields are private | |
273 | /// to prevent modification. | |
274 | /// | |
9e0c209e | 275 | /// The [`format_args!`] macro will safely create an instance of this structure |
1a4d82fc | 276 | /// and pass it to a function or closure, passed as the first argument. The |
9e0c209e SL |
277 | /// macro validates the format string at compile-time so usage of the [`write`] |
278 | /// and [`format`] functions can be safely performed. | |
279 | /// | |
280 | /// [`format_args!`]: ../../std/macro.format_args.html | |
281 | /// [`format`]: ../../std/fmt/fn.format.html | |
282 | /// [`write`]: ../../std/fmt/fn.write.html | |
85aaf69f | 283 | #[stable(feature = "rust1", since = "1.0.0")] |
c34b1796 | 284 | #[derive(Copy, Clone)] |
1a4d82fc JJ |
285 | pub struct Arguments<'a> { |
286 | // Format string pieces to print. | |
287 | pieces: &'a [&'a str], | |
288 | ||
289 | // Placeholder specs, or `None` if all specs are default (as in "{}{}"). | |
85aaf69f | 290 | fmt: Option<&'a [rt::v1::Argument]>, |
1a4d82fc JJ |
291 | |
292 | // Dynamic arguments for interpolation, to be interleaved with string | |
293 | // pieces. (Every argument is preceded by a string piece.) | |
85aaf69f | 294 | args: &'a [ArgumentV1<'a>], |
1a4d82fc JJ |
295 | } |
296 | ||
85aaf69f SL |
297 | #[stable(feature = "rust1", since = "1.0.0")] |
298 | impl<'a> Debug for Arguments<'a> { | |
1a4d82fc | 299 | fn fmt(&self, fmt: &mut Formatter) -> Result { |
85aaf69f | 300 | Display::fmt(self, fmt) |
1a4d82fc JJ |
301 | } |
302 | } | |
303 | ||
85aaf69f SL |
304 | #[stable(feature = "rust1", since = "1.0.0")] |
305 | impl<'a> Display for Arguments<'a> { | |
1a4d82fc JJ |
306 | fn fmt(&self, fmt: &mut Formatter) -> Result { |
307 | write(fmt.buf, *self) | |
308 | } | |
309 | } | |
310 | ||
c1a9b12d SL |
311 | /// Format trait for the `?` character. |
312 | /// | |
313 | /// `Debug` should format the output in a programmer-facing, debugging context. | |
62682a34 SL |
314 | /// |
315 | /// Generally speaking, you should just `derive` a `Debug` implementation. | |
316 | /// | |
c1a9b12d SL |
317 | /// When used with the alternate format specifier `#?`, the output is pretty-printed. |
318 | /// | |
319 | /// For more information on formatters, see [the module-level documentation][module]. | |
320 | /// | |
b039eaaf | 321 | /// [module]: ../../std/fmt/index.html |
c1a9b12d | 322 | /// |
3157f602 XL |
323 | /// This trait can be used with `#[derive]` if all fields implement `Debug`. When |
324 | /// `derive`d for structs, it will use the name of the `struct`, then `{`, then a | |
325 | /// comma-separated list of each field's name and `Debug` value, then `}`. For | |
326 | /// `enum`s, it will use the name of the variant and, if applicable, `(`, then the | |
327 | /// `Debug` values of the fields, then `)`. | |
92a42be0 | 328 | /// |
62682a34 SL |
329 | /// # Examples |
330 | /// | |
331 | /// Deriving an implementation: | |
332 | /// | |
333 | /// ``` | |
334 | /// #[derive(Debug)] | |
335 | /// struct Point { | |
336 | /// x: i32, | |
337 | /// y: i32, | |
338 | /// } | |
339 | /// | |
340 | /// let origin = Point { x: 0, y: 0 }; | |
341 | /// | |
342 | /// println!("The origin is: {:?}", origin); | |
343 | /// ``` | |
344 | /// | |
345 | /// Manually implementing: | |
346 | /// | |
347 | /// ``` | |
348 | /// use std::fmt; | |
349 | /// | |
350 | /// struct Point { | |
351 | /// x: i32, | |
352 | /// y: i32, | |
353 | /// } | |
354 | /// | |
355 | /// impl fmt::Debug for Point { | |
356 | /// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { | |
92a42be0 | 357 | /// write!(f, "Point {{ x: {}, y: {} }}", self.x, self.y) |
62682a34 SL |
358 | /// } |
359 | /// } | |
360 | /// | |
361 | /// let origin = Point { x: 0, y: 0 }; | |
362 | /// | |
363 | /// println!("The origin is: {:?}", origin); | |
364 | /// ``` | |
365 | /// | |
c1a9b12d SL |
366 | /// This outputs: |
367 | /// | |
368 | /// ```text | |
369 | /// The origin is: Point { x: 0, y: 0 } | |
370 | /// ``` | |
371 | /// | |
62682a34 SL |
372 | /// There are a number of `debug_*` methods on `Formatter` to help you with manual |
373 | /// implementations, such as [`debug_struct`][debug_struct]. | |
374 | /// | |
c1a9b12d SL |
375 | /// `Debug` implementations using either `derive` or the debug builder API |
376 | /// on `Formatter` support pretty printing using the alternate flag: `{:#?}`. | |
377 | /// | |
9cc50fc6 | 378 | /// [debug_struct]: ../../std/fmt/struct.Formatter.html#method.debug_struct |
c1a9b12d SL |
379 | /// |
380 | /// Pretty printing with `#?`: | |
381 | /// | |
382 | /// ``` | |
383 | /// #[derive(Debug)] | |
384 | /// struct Point { | |
385 | /// x: i32, | |
386 | /// y: i32, | |
387 | /// } | |
388 | /// | |
389 | /// let origin = Point { x: 0, y: 0 }; | |
390 | /// | |
391 | /// println!("The origin is: {:#?}", origin); | |
392 | /// ``` | |
393 | /// | |
394 | /// This outputs: | |
395 | /// | |
396 | /// ```text | |
397 | /// The origin is: Point { | |
398 | /// x: 0, | |
399 | /// y: 0 | |
400 | /// } | |
401 | /// ``` | |
85aaf69f SL |
402 | #[stable(feature = "rust1", since = "1.0.0")] |
403 | #[rustc_on_unimplemented = "`{Self}` cannot be formatted using `:?`; if it is \ | |
404 | defined in your crate, add `#[derive(Debug)]` or \ | |
405 | manually implement it"] | |
406 | #[lang = "debug_trait"] | |
407 | pub trait Debug { | |
408 | /// Formats the value using the given formatter. | |
409 | #[stable(feature = "rust1", since = "1.0.0")] | |
1a4d82fc JJ |
410 | fn fmt(&self, &mut Formatter) -> Result; |
411 | } | |
412 | ||
c1a9b12d SL |
413 | /// Format trait for an empty format, `{}`. |
414 | /// | |
415 | /// `Display` is similar to [`Debug`][debug], but `Display` is for user-facing | |
416 | /// output, and so cannot be derived. | |
417 | /// | |
418 | /// [debug]: trait.Debug.html | |
419 | /// | |
420 | /// For more information on formatters, see [the module-level documentation][module]. | |
421 | /// | |
b039eaaf | 422 | /// [module]: ../../std/fmt/index.html |
c1a9b12d SL |
423 | /// |
424 | /// # Examples | |
425 | /// | |
426 | /// Implementing `Display` on a type: | |
427 | /// | |
428 | /// ``` | |
429 | /// use std::fmt; | |
430 | /// | |
431 | /// struct Point { | |
432 | /// x: i32, | |
433 | /// y: i32, | |
434 | /// } | |
435 | /// | |
436 | /// impl fmt::Display for Point { | |
437 | /// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { | |
438 | /// write!(f, "({}, {})", self.x, self.y) | |
439 | /// } | |
440 | /// } | |
441 | /// | |
442 | /// let origin = Point { x: 0, y: 0 }; | |
443 | /// | |
444 | /// println!("The origin is: {}", origin); | |
445 | /// ``` | |
85aaf69f SL |
446 | #[rustc_on_unimplemented = "`{Self}` cannot be formatted with the default \ |
447 | formatter; try using `:?` instead if you are using \ | |
448 | a format string"] | |
449 | #[stable(feature = "rust1", since = "1.0.0")] | |
450 | pub trait Display { | |
451 | /// Formats the value using the given formatter. | |
452 | #[stable(feature = "rust1", since = "1.0.0")] | |
1a4d82fc JJ |
453 | fn fmt(&self, &mut Formatter) -> Result; |
454 | } | |
455 | ||
c1a9b12d SL |
456 | /// Format trait for the `o` character. |
457 | /// | |
458 | /// The `Octal` trait should format its output as a number in base-8. | |
459 | /// | |
460 | /// The alternate flag, `#`, adds a `0o` in front of the output. | |
461 | /// | |
462 | /// For more information on formatters, see [the module-level documentation][module]. | |
463 | /// | |
b039eaaf | 464 | /// [module]: ../../std/fmt/index.html |
c1a9b12d SL |
465 | /// |
466 | /// # Examples | |
467 | /// | |
468 | /// Basic usage with `i32`: | |
469 | /// | |
470 | /// ``` | |
471 | /// let x = 42; // 42 is '52' in octal | |
472 | /// | |
473 | /// assert_eq!(format!("{:o}", x), "52"); | |
474 | /// assert_eq!(format!("{:#o}", x), "0o52"); | |
475 | /// ``` | |
476 | /// | |
477 | /// Implementing `Octal` on a type: | |
478 | /// | |
479 | /// ``` | |
480 | /// use std::fmt; | |
481 | /// | |
482 | /// struct Length(i32); | |
483 | /// | |
484 | /// impl fmt::Octal for Length { | |
485 | /// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { | |
486 | /// let val = self.0; | |
487 | /// | |
488 | /// write!(f, "{:o}", val) // delegate to i32's implementation | |
489 | /// } | |
490 | /// } | |
491 | /// | |
492 | /// let l = Length(9); | |
493 | /// | |
494 | /// println!("l as octal is: {:o}", l); | |
495 | /// ``` | |
85aaf69f | 496 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
497 | pub trait Octal { |
498 | /// Formats the value using the given formatter. | |
85aaf69f | 499 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
500 | fn fmt(&self, &mut Formatter) -> Result; |
501 | } | |
502 | ||
c1a9b12d SL |
503 | /// Format trait for the `b` character. |
504 | /// | |
505 | /// The `Binary` trait should format its output as a number in binary. | |
506 | /// | |
507 | /// The alternate flag, `#`, adds a `0b` in front of the output. | |
508 | /// | |
509 | /// For more information on formatters, see [the module-level documentation][module]. | |
510 | /// | |
b039eaaf | 511 | /// [module]: ../../std/fmt/index.html |
c1a9b12d SL |
512 | /// |
513 | /// # Examples | |
514 | /// | |
515 | /// Basic usage with `i32`: | |
516 | /// | |
517 | /// ``` | |
518 | /// let x = 42; // 42 is '101010' in binary | |
519 | /// | |
520 | /// assert_eq!(format!("{:b}", x), "101010"); | |
521 | /// assert_eq!(format!("{:#b}", x), "0b101010"); | |
522 | /// ``` | |
523 | /// | |
524 | /// Implementing `Binary` on a type: | |
525 | /// | |
526 | /// ``` | |
527 | /// use std::fmt; | |
528 | /// | |
529 | /// struct Length(i32); | |
530 | /// | |
531 | /// impl fmt::Binary for Length { | |
532 | /// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { | |
533 | /// let val = self.0; | |
534 | /// | |
535 | /// write!(f, "{:b}", val) // delegate to i32's implementation | |
536 | /// } | |
537 | /// } | |
538 | /// | |
539 | /// let l = Length(107); | |
540 | /// | |
541 | /// println!("l as binary is: {:b}", l); | |
542 | /// ``` | |
85aaf69f | 543 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
544 | pub trait Binary { |
545 | /// Formats the value using the given formatter. | |
85aaf69f | 546 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
547 | fn fmt(&self, &mut Formatter) -> Result; |
548 | } | |
549 | ||
c1a9b12d SL |
550 | /// Format trait for the `x` character. |
551 | /// | |
b039eaaf | 552 | /// The `LowerHex` trait should format its output as a number in hexadecimal, with `a` through `f` |
c1a9b12d SL |
553 | /// in lower case. |
554 | /// | |
555 | /// The alternate flag, `#`, adds a `0x` in front of the output. | |
556 | /// | |
557 | /// For more information on formatters, see [the module-level documentation][module]. | |
558 | /// | |
b039eaaf | 559 | /// [module]: ../../std/fmt/index.html |
c1a9b12d SL |
560 | /// |
561 | /// # Examples | |
562 | /// | |
563 | /// Basic usage with `i32`: | |
564 | /// | |
565 | /// ``` | |
566 | /// let x = 42; // 42 is '2a' in hex | |
567 | /// | |
568 | /// assert_eq!(format!("{:x}", x), "2a"); | |
569 | /// assert_eq!(format!("{:#x}", x), "0x2a"); | |
570 | /// ``` | |
571 | /// | |
572 | /// Implementing `LowerHex` on a type: | |
573 | /// | |
574 | /// ``` | |
575 | /// use std::fmt; | |
576 | /// | |
577 | /// struct Length(i32); | |
578 | /// | |
579 | /// impl fmt::LowerHex for Length { | |
580 | /// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { | |
581 | /// let val = self.0; | |
582 | /// | |
583 | /// write!(f, "{:x}", val) // delegate to i32's implementation | |
584 | /// } | |
585 | /// } | |
586 | /// | |
587 | /// let l = Length(9); | |
588 | /// | |
589 | /// println!("l as hex is: {:x}", l); | |
590 | /// ``` | |
85aaf69f | 591 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
592 | pub trait LowerHex { |
593 | /// Formats the value using the given formatter. | |
85aaf69f | 594 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
595 | fn fmt(&self, &mut Formatter) -> Result; |
596 | } | |
597 | ||
c1a9b12d SL |
598 | /// Format trait for the `X` character. |
599 | /// | |
b039eaaf | 600 | /// The `UpperHex` trait should format its output as a number in hexadecimal, with `A` through `F` |
c1a9b12d SL |
601 | /// in upper case. |
602 | /// | |
603 | /// The alternate flag, `#`, adds a `0x` in front of the output. | |
604 | /// | |
605 | /// For more information on formatters, see [the module-level documentation][module]. | |
606 | /// | |
b039eaaf | 607 | /// [module]: ../../std/fmt/index.html |
c1a9b12d SL |
608 | /// |
609 | /// # Examples | |
610 | /// | |
611 | /// Basic usage with `i32`: | |
612 | /// | |
613 | /// ``` | |
614 | /// let x = 42; // 42 is '2A' in hex | |
615 | /// | |
616 | /// assert_eq!(format!("{:X}", x), "2A"); | |
617 | /// assert_eq!(format!("{:#X}", x), "0x2A"); | |
618 | /// ``` | |
619 | /// | |
620 | /// Implementing `UpperHex` on a type: | |
621 | /// | |
622 | /// ``` | |
623 | /// use std::fmt; | |
624 | /// | |
625 | /// struct Length(i32); | |
626 | /// | |
627 | /// impl fmt::UpperHex for Length { | |
628 | /// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { | |
629 | /// let val = self.0; | |
630 | /// | |
631 | /// write!(f, "{:X}", val) // delegate to i32's implementation | |
632 | /// } | |
633 | /// } | |
634 | /// | |
635 | /// let l = Length(9); | |
636 | /// | |
637 | /// println!("l as hex is: {:X}", l); | |
638 | /// ``` | |
85aaf69f | 639 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
640 | pub trait UpperHex { |
641 | /// Formats the value using the given formatter. | |
85aaf69f | 642 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
643 | fn fmt(&self, &mut Formatter) -> Result; |
644 | } | |
645 | ||
c1a9b12d SL |
646 | /// Format trait for the `p` character. |
647 | /// | |
648 | /// The `Pointer` trait should format its output as a memory location. This is commonly presented | |
b039eaaf | 649 | /// as hexadecimal. |
c1a9b12d SL |
650 | /// |
651 | /// For more information on formatters, see [the module-level documentation][module]. | |
652 | /// | |
b039eaaf | 653 | /// [module]: ../../std/fmt/index.html |
c1a9b12d SL |
654 | /// |
655 | /// # Examples | |
656 | /// | |
657 | /// Basic usage with `&i32`: | |
658 | /// | |
659 | /// ``` | |
660 | /// let x = &42; | |
661 | /// | |
662 | /// let address = format!("{:p}", x); // this produces something like '0x7f06092ac6d0' | |
663 | /// ``` | |
664 | /// | |
665 | /// Implementing `Pointer` on a type: | |
666 | /// | |
667 | /// ``` | |
668 | /// use std::fmt; | |
669 | /// | |
670 | /// struct Length(i32); | |
671 | /// | |
672 | /// impl fmt::Pointer for Length { | |
673 | /// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { | |
674 | /// // use `as` to convert to a `*const T`, which implements Pointer, which we can use | |
675 | /// | |
676 | /// write!(f, "{:p}", self as *const Length) | |
677 | /// } | |
678 | /// } | |
679 | /// | |
680 | /// let l = Length(42); | |
681 | /// | |
682 | /// println!("l is in memory here: {:p}", l); | |
683 | /// ``` | |
85aaf69f | 684 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
685 | pub trait Pointer { |
686 | /// Formats the value using the given formatter. | |
85aaf69f | 687 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
688 | fn fmt(&self, &mut Formatter) -> Result; |
689 | } | |
690 | ||
c1a9b12d SL |
691 | /// Format trait for the `e` character. |
692 | /// | |
693 | /// The `LowerExp` trait should format its output in scientific notation with a lower-case `e`. | |
694 | /// | |
695 | /// For more information on formatters, see [the module-level documentation][module]. | |
696 | /// | |
b039eaaf | 697 | /// [module]: ../../std/fmt/index.html |
c1a9b12d SL |
698 | /// |
699 | /// # Examples | |
700 | /// | |
701 | /// Basic usage with `i32`: | |
702 | /// | |
703 | /// ``` | |
704 | /// let x = 42.0; // 42.0 is '4.2e1' in scientific notation | |
705 | /// | |
706 | /// assert_eq!(format!("{:e}", x), "4.2e1"); | |
707 | /// ``` | |
708 | /// | |
709 | /// Implementing `LowerExp` on a type: | |
710 | /// | |
711 | /// ``` | |
712 | /// use std::fmt; | |
713 | /// | |
714 | /// struct Length(i32); | |
715 | /// | |
716 | /// impl fmt::LowerExp for Length { | |
717 | /// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { | |
718 | /// let val = self.0; | |
719 | /// write!(f, "{}e1", val / 10) | |
720 | /// } | |
721 | /// } | |
722 | /// | |
723 | /// let l = Length(100); | |
724 | /// | |
725 | /// println!("l in scientific notation is: {:e}", l); | |
726 | /// ``` | |
85aaf69f | 727 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
728 | pub trait LowerExp { |
729 | /// Formats the value using the given formatter. | |
85aaf69f | 730 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
731 | fn fmt(&self, &mut Formatter) -> Result; |
732 | } | |
733 | ||
c1a9b12d SL |
734 | /// Format trait for the `E` character. |
735 | /// | |
736 | /// The `UpperExp` trait should format its output in scientific notation with an upper-case `E`. | |
737 | /// | |
738 | /// For more information on formatters, see [the module-level documentation][module]. | |
739 | /// | |
b039eaaf | 740 | /// [module]: ../../std/fmt/index.html |
c1a9b12d SL |
741 | /// |
742 | /// # Examples | |
743 | /// | |
744 | /// Basic usage with `f32`: | |
745 | /// | |
746 | /// ``` | |
747 | /// let x = 42.0; // 42.0 is '4.2E1' in scientific notation | |
748 | /// | |
749 | /// assert_eq!(format!("{:E}", x), "4.2E1"); | |
750 | /// ``` | |
751 | /// | |
752 | /// Implementing `UpperExp` on a type: | |
753 | /// | |
754 | /// ``` | |
755 | /// use std::fmt; | |
756 | /// | |
757 | /// struct Length(i32); | |
758 | /// | |
759 | /// impl fmt::UpperExp for Length { | |
760 | /// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { | |
761 | /// let val = self.0; | |
762 | /// write!(f, "{}E1", val / 10) | |
763 | /// } | |
764 | /// } | |
765 | /// | |
766 | /// let l = Length(100); | |
767 | /// | |
768 | /// println!("l in scientific notation is: {:E}", l); | |
769 | /// ``` | |
85aaf69f | 770 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
771 | pub trait UpperExp { |
772 | /// Formats the value using the given formatter. | |
85aaf69f | 773 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
774 | fn fmt(&self, &mut Formatter) -> Result; |
775 | } | |
776 | ||
777 | /// The `write` function takes an output stream, a precompiled format string, | |
778 | /// and a list of arguments. The arguments will be formatted according to the | |
779 | /// specified format string into the output stream provided. | |
780 | /// | |
781 | /// # Arguments | |
782 | /// | |
783 | /// * output - the buffer to write output to | |
784 | /// * args - the precompiled arguments generated by `format_args!` | |
a7813a04 XL |
785 | /// |
786 | /// # Examples | |
787 | /// | |
788 | /// Basic usage: | |
789 | /// | |
790 | /// ``` | |
791 | /// use std::fmt; | |
792 | /// | |
793 | /// let mut output = String::new(); | |
794 | /// fmt::write(&mut output, format_args!("Hello {}!", "world")) | |
795 | /// .expect("Error occurred while trying to write in String"); | |
796 | /// assert_eq!(output, "Hello world!"); | |
797 | /// ``` | |
798 | /// | |
c30ab7b3 | 799 | /// Please note that using [`write!`] might be preferrable. Example: |
a7813a04 XL |
800 | /// |
801 | /// ``` | |
802 | /// use std::fmt::Write; | |
803 | /// | |
804 | /// let mut output = String::new(); | |
805 | /// write!(&mut output, "Hello {}!", "world") | |
806 | /// .expect("Error occurred while trying to write in String"); | |
807 | /// assert_eq!(output, "Hello world!"); | |
808 | /// ``` | |
809 | /// | |
c30ab7b3 | 810 | /// [`write!`]: ../../std/macro.write.html |
85aaf69f SL |
811 | #[stable(feature = "rust1", since = "1.0.0")] |
812 | pub fn write(output: &mut Write, args: Arguments) -> Result { | |
1a4d82fc JJ |
813 | let mut formatter = Formatter { |
814 | flags: 0, | |
815 | width: None, | |
816 | precision: None, | |
817 | buf: output, | |
54a0048b | 818 | align: rt::v1::Alignment::Unknown, |
1a4d82fc JJ |
819 | fill: ' ', |
820 | args: args.args, | |
821 | curarg: args.args.iter(), | |
822 | }; | |
823 | ||
824 | let mut pieces = args.pieces.iter(); | |
825 | ||
826 | match args.fmt { | |
827 | None => { | |
828 | // We can use default formatting parameters for all arguments. | |
829 | for (arg, piece) in args.args.iter().zip(pieces.by_ref()) { | |
54a0048b SL |
830 | formatter.buf.write_str(*piece)?; |
831 | (arg.formatter)(arg.value, &mut formatter)?; | |
1a4d82fc JJ |
832 | } |
833 | } | |
834 | Some(fmt) => { | |
835 | // Every spec has a corresponding argument that is preceded by | |
836 | // a string piece. | |
837 | for (arg, piece) in fmt.iter().zip(pieces.by_ref()) { | |
54a0048b SL |
838 | formatter.buf.write_str(*piece)?; |
839 | formatter.run(arg)?; | |
1a4d82fc JJ |
840 | } |
841 | } | |
842 | } | |
843 | ||
844 | // There can be only one trailing string piece left. | |
3157f602 XL |
845 | if let Some(piece) = pieces.next() { |
846 | formatter.buf.write_str(*piece)?; | |
1a4d82fc JJ |
847 | } |
848 | ||
849 | Ok(()) | |
850 | } | |
851 | ||
852 | impl<'a> Formatter<'a> { | |
853 | ||
854 | // First up is the collection of functions used to execute a format string | |
855 | // at runtime. This consumes all of the compile-time statics generated by | |
856 | // the format! syntax extension. | |
85aaf69f | 857 | fn run(&mut self, arg: &rt::v1::Argument) -> Result { |
1a4d82fc JJ |
858 | // Fill in the format parameters into the formatter |
859 | self.fill = arg.format.fill; | |
860 | self.align = arg.format.align; | |
861 | self.flags = arg.format.flags; | |
862 | self.width = self.getcount(&arg.format.width); | |
863 | self.precision = self.getcount(&arg.format.precision); | |
864 | ||
865 | // Extract the correct argument | |
866 | let value = match arg.position { | |
85aaf69f SL |
867 | rt::v1::Position::Next => { *self.curarg.next().unwrap() } |
868 | rt::v1::Position::At(i) => self.args[i], | |
1a4d82fc JJ |
869 | }; |
870 | ||
871 | // Then actually do some printing | |
872 | (value.formatter)(value.value, self) | |
873 | } | |
874 | ||
c34b1796 | 875 | fn getcount(&mut self, cnt: &rt::v1::Count) -> Option<usize> { |
1a4d82fc | 876 | match *cnt { |
85aaf69f SL |
877 | rt::v1::Count::Is(n) => Some(n), |
878 | rt::v1::Count::Implied => None, | |
879 | rt::v1::Count::Param(i) => { | |
c34b1796 | 880 | self.args[i].as_usize() |
1a4d82fc | 881 | } |
85aaf69f | 882 | rt::v1::Count::NextParam => { |
c34b1796 | 883 | self.curarg.next().and_then(|arg| arg.as_usize()) |
1a4d82fc JJ |
884 | } |
885 | } | |
886 | } | |
887 | ||
888 | // Helper methods used for padding and processing formatting arguments that | |
889 | // all formatting traits can use. | |
890 | ||
891 | /// Performs the correct padding for an integer which has already been | |
85aaf69f SL |
892 | /// emitted into a str. The str should *not* contain the sign for the |
893 | /// integer, that will be added by this method. | |
1a4d82fc JJ |
894 | /// |
895 | /// # Arguments | |
896 | /// | |
9cc50fc6 | 897 | /// * is_nonnegative - whether the original integer was either positive or zero. |
c34b1796 | 898 | /// * prefix - if the '#' character (Alternate) is provided, this |
1a4d82fc JJ |
899 | /// is the prefix to put in front of the number. |
900 | /// * buf - the byte array that the number has been formatted into | |
901 | /// | |
902 | /// This function will correctly account for the flags provided as well as | |
903 | /// the minimum width. It will not take precision into account. | |
85aaf69f | 904 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc | 905 | pub fn pad_integral(&mut self, |
9cc50fc6 | 906 | is_nonnegative: bool, |
1a4d82fc JJ |
907 | prefix: &str, |
908 | buf: &str) | |
909 | -> Result { | |
1a4d82fc JJ |
910 | let mut width = buf.len(); |
911 | ||
912 | let mut sign = None; | |
9cc50fc6 | 913 | if !is_nonnegative { |
1a4d82fc | 914 | sign = Some('-'); width += 1; |
b039eaaf | 915 | } else if self.sign_plus() { |
1a4d82fc JJ |
916 | sign = Some('+'); width += 1; |
917 | } | |
918 | ||
919 | let mut prefixed = false; | |
b039eaaf | 920 | if self.alternate() { |
92a42be0 | 921 | prefixed = true; width += prefix.chars().count(); |
1a4d82fc JJ |
922 | } |
923 | ||
924 | // Writes the sign if it exists, and then the prefix if it was requested | |
85aaf69f SL |
925 | let write_prefix = |f: &mut Formatter| { |
926 | if let Some(c) = sign { | |
c30ab7b3 | 927 | f.buf.write_str(c.encode_utf8(&mut [0; 4]))?; |
1a4d82fc JJ |
928 | } |
929 | if prefixed { f.buf.write_str(prefix) } | |
930 | else { Ok(()) } | |
931 | }; | |
932 | ||
933 | // The `width` field is more of a `min-width` parameter at this point. | |
934 | match self.width { | |
935 | // If there's no minimum length requirements then we can just | |
936 | // write the bytes. | |
937 | None => { | |
54a0048b | 938 | write_prefix(self)?; self.buf.write_str(buf) |
1a4d82fc JJ |
939 | } |
940 | // Check if we're over the minimum width, if so then we can also | |
941 | // just write the bytes. | |
942 | Some(min) if width >= min => { | |
54a0048b | 943 | write_prefix(self)?; self.buf.write_str(buf) |
1a4d82fc JJ |
944 | } |
945 | // The sign and prefix goes before the padding if the fill character | |
946 | // is zero | |
b039eaaf | 947 | Some(min) if self.sign_aware_zero_pad() => { |
1a4d82fc | 948 | self.fill = '0'; |
54a0048b SL |
949 | write_prefix(self)?; |
950 | self.with_padding(min - width, rt::v1::Alignment::Right, |f| { | |
1a4d82fc JJ |
951 | f.buf.write_str(buf) |
952 | }) | |
953 | } | |
954 | // Otherwise, the sign and prefix goes after the padding | |
955 | Some(min) => { | |
54a0048b SL |
956 | self.with_padding(min - width, rt::v1::Alignment::Right, |f| { |
957 | write_prefix(f)?; f.buf.write_str(buf) | |
1a4d82fc JJ |
958 | }) |
959 | } | |
960 | } | |
961 | } | |
962 | ||
963 | /// This function takes a string slice and emits it to the internal buffer | |
964 | /// after applying the relevant formatting flags specified. The flags | |
965 | /// recognized for generic strings are: | |
966 | /// | |
967 | /// * width - the minimum width of what to emit | |
968 | /// * fill/align - what to emit and where to emit it if the string | |
969 | /// provided needs to be padded | |
970 | /// * precision - the maximum length to emit, the string is truncated if it | |
971 | /// is longer than this length | |
972 | /// | |
973 | /// Notably this function ignored the `flag` parameters | |
85aaf69f | 974 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
975 | pub fn pad(&mut self, s: &str) -> Result { |
976 | // Make sure there's a fast path up front | |
977 | if self.width.is_none() && self.precision.is_none() { | |
978 | return self.buf.write_str(s); | |
979 | } | |
980 | // The `precision` field can be interpreted as a `max-width` for the | |
5bcae85e SL |
981 | // string being formatted. |
982 | let s = if let Some(max) = self.precision { | |
983 | // If our string is longer that the precision, then we must have | |
984 | // truncation. However other flags like `fill`, `width` and `align` | |
985 | // must act as always. | |
92a42be0 | 986 | if let Some((i, _)) = s.char_indices().skip(max).next() { |
5bcae85e SL |
987 | &s[..i] |
988 | } else { | |
989 | &s | |
1a4d82fc | 990 | } |
5bcae85e SL |
991 | } else { |
992 | &s | |
993 | }; | |
1a4d82fc JJ |
994 | // The `width` field is more of a `min-width` parameter at this point. |
995 | match self.width { | |
996 | // If we're under the maximum length, and there's no minimum length | |
997 | // requirements, then we can just emit the string | |
998 | None => self.buf.write_str(s), | |
999 | // If we're under the maximum width, check if we're over the minimum | |
1000 | // width, if so it's as easy as just emitting the string. | |
92a42be0 | 1001 | Some(width) if s.chars().count() >= width => { |
1a4d82fc JJ |
1002 | self.buf.write_str(s) |
1003 | } | |
1004 | // If we're under both the maximum and the minimum width, then fill | |
1005 | // up the minimum width with the specified string + some alignment. | |
1006 | Some(width) => { | |
54a0048b SL |
1007 | let align = rt::v1::Alignment::Left; |
1008 | self.with_padding(width - s.chars().count(), align, |me| { | |
1a4d82fc JJ |
1009 | me.buf.write_str(s) |
1010 | }) | |
1011 | } | |
1012 | } | |
1013 | } | |
1014 | ||
1015 | /// Runs a callback, emitting the correct padding either before or | |
1016 | /// afterwards depending on whether right or left alignment is requested. | |
54a0048b | 1017 | fn with_padding<F>(&mut self, padding: usize, default: rt::v1::Alignment, |
85aaf69f SL |
1018 | f: F) -> Result |
1019 | where F: FnOnce(&mut Formatter) -> Result, | |
1a4d82fc | 1020 | { |
1a4d82fc | 1021 | let align = match self.align { |
54a0048b | 1022 | rt::v1::Alignment::Unknown => default, |
1a4d82fc JJ |
1023 | _ => self.align |
1024 | }; | |
1025 | ||
1026 | let (pre_pad, post_pad) = match align { | |
54a0048b SL |
1027 | rt::v1::Alignment::Left => (0, padding), |
1028 | rt::v1::Alignment::Right | | |
1029 | rt::v1::Alignment::Unknown => (padding, 0), | |
1030 | rt::v1::Alignment::Center => (padding / 2, (padding + 1) / 2), | |
1a4d82fc JJ |
1031 | }; |
1032 | ||
c30ab7b3 SL |
1033 | let mut fill = [0; 4]; |
1034 | let fill = self.fill.encode_utf8(&mut fill); | |
1a4d82fc | 1035 | |
85aaf69f | 1036 | for _ in 0..pre_pad { |
54a0048b | 1037 | self.buf.write_str(fill)?; |
1a4d82fc JJ |
1038 | } |
1039 | ||
54a0048b | 1040 | f(self)?; |
1a4d82fc | 1041 | |
85aaf69f | 1042 | for _ in 0..post_pad { |
54a0048b | 1043 | self.buf.write_str(fill)?; |
1a4d82fc JJ |
1044 | } |
1045 | ||
1046 | Ok(()) | |
1047 | } | |
1048 | ||
d9579d0f AL |
1049 | /// Takes the formatted parts and applies the padding. |
1050 | /// Assumes that the caller already has rendered the parts with required precision, | |
1051 | /// so that `self.precision` can be ignored. | |
1052 | fn pad_formatted_parts(&mut self, formatted: &flt2dec::Formatted) -> Result { | |
1053 | if let Some(mut width) = self.width { | |
1054 | // for the sign-aware zero padding, we render the sign first and | |
1055 | // behave as if we had no sign from the beginning. | |
1056 | let mut formatted = formatted.clone(); | |
1057 | let mut align = self.align; | |
1058 | let old_fill = self.fill; | |
b039eaaf | 1059 | if self.sign_aware_zero_pad() { |
d9579d0f AL |
1060 | // a sign always goes first |
1061 | let sign = unsafe { str::from_utf8_unchecked(formatted.sign) }; | |
54a0048b | 1062 | self.buf.write_str(sign)?; |
d9579d0f AL |
1063 | |
1064 | // remove the sign from the formatted parts | |
1065 | formatted.sign = b""; | |
1066 | width = if width < sign.len() { 0 } else { width - sign.len() }; | |
54a0048b | 1067 | align = rt::v1::Alignment::Right; |
d9579d0f AL |
1068 | self.fill = '0'; |
1069 | } | |
1070 | ||
1071 | // remaining parts go through the ordinary padding process. | |
1072 | let len = formatted.len(); | |
1073 | let ret = if width <= len { // no padding | |
1074 | self.write_formatted_parts(&formatted) | |
1075 | } else { | |
1076 | self.with_padding(width - len, align, |f| { | |
1077 | f.write_formatted_parts(&formatted) | |
1078 | }) | |
1079 | }; | |
1080 | self.fill = old_fill; | |
1081 | ret | |
1082 | } else { | |
1083 | // this is the common case and we take a shortcut | |
1084 | self.write_formatted_parts(formatted) | |
1085 | } | |
1086 | } | |
1087 | ||
1088 | fn write_formatted_parts(&mut self, formatted: &flt2dec::Formatted) -> Result { | |
1089 | fn write_bytes(buf: &mut Write, s: &[u8]) -> Result { | |
1090 | buf.write_str(unsafe { str::from_utf8_unchecked(s) }) | |
1091 | } | |
1092 | ||
1093 | if !formatted.sign.is_empty() { | |
54a0048b | 1094 | write_bytes(self.buf, formatted.sign)?; |
d9579d0f AL |
1095 | } |
1096 | for part in formatted.parts { | |
1097 | match *part { | |
1098 | flt2dec::Part::Zero(mut nzeroes) => { | |
1099 | const ZEROES: &'static str = // 64 zeroes | |
1100 | "0000000000000000000000000000000000000000000000000000000000000000"; | |
1101 | while nzeroes > ZEROES.len() { | |
54a0048b | 1102 | self.buf.write_str(ZEROES)?; |
d9579d0f AL |
1103 | nzeroes -= ZEROES.len(); |
1104 | } | |
1105 | if nzeroes > 0 { | |
54a0048b | 1106 | self.buf.write_str(&ZEROES[..nzeroes])?; |
d9579d0f AL |
1107 | } |
1108 | } | |
1109 | flt2dec::Part::Num(mut v) => { | |
1110 | let mut s = [0; 5]; | |
1111 | let len = part.len(); | |
1112 | for c in s[..len].iter_mut().rev() { | |
1113 | *c = b'0' + (v % 10) as u8; | |
1114 | v /= 10; | |
1115 | } | |
54a0048b | 1116 | write_bytes(self.buf, &s[..len])?; |
d9579d0f AL |
1117 | } |
1118 | flt2dec::Part::Copy(buf) => { | |
54a0048b | 1119 | write_bytes(self.buf, buf)?; |
d9579d0f AL |
1120 | } |
1121 | } | |
1122 | } | |
1123 | Ok(()) | |
1124 | } | |
1125 | ||
1a4d82fc JJ |
1126 | /// Writes some data to the underlying buffer contained within this |
1127 | /// formatter. | |
85aaf69f | 1128 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1129 | pub fn write_str(&mut self, data: &str) -> Result { |
1130 | self.buf.write_str(data) | |
1131 | } | |
1132 | ||
1133 | /// Writes some formatted information into this instance | |
85aaf69f | 1134 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1135 | pub fn write_fmt(&mut self, fmt: Arguments) -> Result { |
1136 | write(self.buf, fmt) | |
1137 | } | |
1138 | ||
1139 | /// Flags for formatting (packed version of rt::Flag) | |
85aaf69f | 1140 | #[stable(feature = "rust1", since = "1.0.0")] |
c34b1796 | 1141 | pub fn flags(&self) -> u32 { self.flags } |
1a4d82fc JJ |
1142 | |
1143 | /// Character used as 'fill' whenever there is alignment | |
b039eaaf | 1144 | #[stable(feature = "fmt_flags", since = "1.5.0")] |
1a4d82fc JJ |
1145 | pub fn fill(&self) -> char { self.fill } |
1146 | ||
1147 | /// Flag indicating what form of alignment was requested | |
b039eaaf | 1148 | #[unstable(feature = "fmt_flags_align", reason = "method was just created", |
e9174d1e | 1149 | issue = "27726")] |
54a0048b SL |
1150 | pub fn align(&self) -> Alignment { |
1151 | match self.align { | |
1152 | rt::v1::Alignment::Left => Alignment::Left, | |
1153 | rt::v1::Alignment::Right => Alignment::Right, | |
1154 | rt::v1::Alignment::Center => Alignment::Center, | |
1155 | rt::v1::Alignment::Unknown => Alignment::Unknown, | |
1156 | } | |
1157 | } | |
1a4d82fc JJ |
1158 | |
1159 | /// Optionally specified integer width that the output should be | |
b039eaaf | 1160 | #[stable(feature = "fmt_flags", since = "1.5.0")] |
c34b1796 | 1161 | pub fn width(&self) -> Option<usize> { self.width } |
1a4d82fc JJ |
1162 | |
1163 | /// Optionally specified precision for numeric types | |
b039eaaf | 1164 | #[stable(feature = "fmt_flags", since = "1.5.0")] |
c34b1796 AL |
1165 | pub fn precision(&self) -> Option<usize> { self.precision } |
1166 | ||
b039eaaf SL |
1167 | /// Determines if the `+` flag was specified. |
1168 | #[stable(feature = "fmt_flags", since = "1.5.0")] | |
1169 | pub fn sign_plus(&self) -> bool { self.flags & (1 << FlagV1::SignPlus as u32) != 0 } | |
1170 | ||
1171 | /// Determines if the `-` flag was specified. | |
1172 | #[stable(feature = "fmt_flags", since = "1.5.0")] | |
1173 | pub fn sign_minus(&self) -> bool { self.flags & (1 << FlagV1::SignMinus as u32) != 0 } | |
1174 | ||
1175 | /// Determines if the `#` flag was specified. | |
1176 | #[stable(feature = "fmt_flags", since = "1.5.0")] | |
1177 | pub fn alternate(&self) -> bool { self.flags & (1 << FlagV1::Alternate as u32) != 0 } | |
1178 | ||
1179 | /// Determines if the `0` flag was specified. | |
1180 | #[stable(feature = "fmt_flags", since = "1.5.0")] | |
1181 | pub fn sign_aware_zero_pad(&self) -> bool { | |
1182 | self.flags & (1 << FlagV1::SignAwareZeroPad as u32) != 0 | |
1183 | } | |
1184 | ||
c34b1796 AL |
1185 | /// Creates a `DebugStruct` builder designed to assist with creation of |
1186 | /// `fmt::Debug` implementations for structs. | |
1187 | /// | |
1188 | /// # Examples | |
1189 | /// | |
1190 | /// ```rust | |
c34b1796 AL |
1191 | /// use std::fmt; |
1192 | /// | |
1193 | /// struct Foo { | |
1194 | /// bar: i32, | |
1195 | /// baz: String, | |
1196 | /// } | |
1197 | /// | |
1198 | /// impl fmt::Debug for Foo { | |
1199 | /// fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { | |
1200 | /// fmt.debug_struct("Foo") | |
1201 | /// .field("bar", &self.bar) | |
1202 | /// .field("baz", &self.baz) | |
1203 | /// .finish() | |
1204 | /// } | |
1205 | /// } | |
1206 | /// | |
1207 | /// // prints "Foo { bar: 10, baz: "Hello World" }" | |
1208 | /// println!("{:?}", Foo { bar: 10, baz: "Hello World".to_string() }); | |
1209 | /// ``` | |
62682a34 | 1210 | #[stable(feature = "debug_builders", since = "1.2.0")] |
c34b1796 AL |
1211 | #[inline] |
1212 | pub fn debug_struct<'b>(&'b mut self, name: &str) -> DebugStruct<'b, 'a> { | |
1213 | builders::debug_struct_new(self, name) | |
1214 | } | |
1215 | ||
1216 | /// Creates a `DebugTuple` builder designed to assist with creation of | |
1217 | /// `fmt::Debug` implementations for tuple structs. | |
1218 | /// | |
1219 | /// # Examples | |
1220 | /// | |
1221 | /// ```rust | |
c34b1796 AL |
1222 | /// use std::fmt; |
1223 | /// | |
1224 | /// struct Foo(i32, String); | |
1225 | /// | |
1226 | /// impl fmt::Debug for Foo { | |
1227 | /// fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { | |
1228 | /// fmt.debug_tuple("Foo") | |
1229 | /// .field(&self.0) | |
1230 | /// .field(&self.1) | |
1231 | /// .finish() | |
1232 | /// } | |
1233 | /// } | |
1234 | /// | |
1235 | /// // prints "Foo(10, "Hello World")" | |
1236 | /// println!("{:?}", Foo(10, "Hello World".to_string())); | |
1237 | /// ``` | |
62682a34 | 1238 | #[stable(feature = "debug_builders", since = "1.2.0")] |
c34b1796 AL |
1239 | #[inline] |
1240 | pub fn debug_tuple<'b>(&'b mut self, name: &str) -> DebugTuple<'b, 'a> { | |
1241 | builders::debug_tuple_new(self, name) | |
1242 | } | |
1243 | ||
1244 | /// Creates a `DebugList` builder designed to assist with creation of | |
1245 | /// `fmt::Debug` implementations for list-like structures. | |
1246 | /// | |
1247 | /// # Examples | |
1248 | /// | |
1249 | /// ```rust | |
c34b1796 AL |
1250 | /// use std::fmt; |
1251 | /// | |
1252 | /// struct Foo(Vec<i32>); | |
1253 | /// | |
1254 | /// impl fmt::Debug for Foo { | |
1255 | /// fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { | |
62682a34 | 1256 | /// fmt.debug_list().entries(self.0.iter()).finish() |
c34b1796 AL |
1257 | /// } |
1258 | /// } | |
1259 | /// | |
1260 | /// // prints "[10, 11]" | |
1261 | /// println!("{:?}", Foo(vec![10, 11])); | |
1262 | /// ``` | |
62682a34 | 1263 | #[stable(feature = "debug_builders", since = "1.2.0")] |
c34b1796 AL |
1264 | #[inline] |
1265 | pub fn debug_list<'b>(&'b mut self) -> DebugList<'b, 'a> { | |
1266 | builders::debug_list_new(self) | |
1267 | } | |
1268 | ||
1269 | /// Creates a `DebugSet` builder designed to assist with creation of | |
1270 | /// `fmt::Debug` implementations for set-like structures. | |
1271 | /// | |
1272 | /// # Examples | |
1273 | /// | |
1274 | /// ```rust | |
c34b1796 AL |
1275 | /// use std::fmt; |
1276 | /// | |
1277 | /// struct Foo(Vec<i32>); | |
1278 | /// | |
1279 | /// impl fmt::Debug for Foo { | |
1280 | /// fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { | |
62682a34 | 1281 | /// fmt.debug_set().entries(self.0.iter()).finish() |
c34b1796 AL |
1282 | /// } |
1283 | /// } | |
1284 | /// | |
1285 | /// // prints "{10, 11}" | |
1286 | /// println!("{:?}", Foo(vec![10, 11])); | |
1287 | /// ``` | |
62682a34 | 1288 | #[stable(feature = "debug_builders", since = "1.2.0")] |
c34b1796 AL |
1289 | #[inline] |
1290 | pub fn debug_set<'b>(&'b mut self) -> DebugSet<'b, 'a> { | |
1291 | builders::debug_set_new(self) | |
1292 | } | |
1293 | ||
1294 | /// Creates a `DebugMap` builder designed to assist with creation of | |
1295 | /// `fmt::Debug` implementations for map-like structures. | |
1296 | /// | |
1297 | /// # Examples | |
1298 | /// | |
1299 | /// ```rust | |
c34b1796 AL |
1300 | /// use std::fmt; |
1301 | /// | |
1302 | /// struct Foo(Vec<(String, i32)>); | |
1303 | /// | |
1304 | /// impl fmt::Debug for Foo { | |
1305 | /// fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { | |
62682a34 | 1306 | /// fmt.debug_map().entries(self.0.iter().map(|&(ref k, ref v)| (k, v))).finish() |
c34b1796 AL |
1307 | /// } |
1308 | /// } | |
1309 | /// | |
1310 | /// // prints "{"A": 10, "B": 11}" | |
1311 | /// println!("{:?}", Foo(vec![("A".to_string(), 10), ("B".to_string(), 11)])); | |
1312 | /// ``` | |
62682a34 | 1313 | #[stable(feature = "debug_builders", since = "1.2.0")] |
c34b1796 AL |
1314 | #[inline] |
1315 | pub fn debug_map<'b>(&'b mut self) -> DebugMap<'b, 'a> { | |
1316 | builders::debug_map_new(self) | |
1317 | } | |
1a4d82fc JJ |
1318 | } |
1319 | ||
62682a34 SL |
1320 | #[stable(since = "1.2.0", feature = "formatter_write")] |
1321 | impl<'a> Write for Formatter<'a> { | |
1322 | fn write_str(&mut self, s: &str) -> Result { | |
1323 | self.buf.write_str(s) | |
1324 | } | |
1325 | ||
1326 | fn write_char(&mut self, c: char) -> Result { | |
1327 | self.buf.write_char(c) | |
1328 | } | |
1329 | ||
1330 | fn write_fmt(&mut self, args: Arguments) -> Result { | |
1331 | write(self.buf, args) | |
1332 | } | |
1333 | } | |
1334 | ||
85aaf69f SL |
1335 | #[stable(feature = "rust1", since = "1.0.0")] |
1336 | impl Display for Error { | |
1a4d82fc | 1337 | fn fmt(&self, f: &mut Formatter) -> Result { |
85aaf69f | 1338 | Display::fmt("an error occurred when formatting an argument", f) |
1a4d82fc JJ |
1339 | } |
1340 | } | |
1341 | ||
1a4d82fc JJ |
1342 | // Implementations of the core formatting traits |
1343 | ||
1344 | macro_rules! fmt_refs { | |
1345 | ($($tr:ident),*) => { | |
1346 | $( | |
85aaf69f | 1347 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1348 | impl<'a, T: ?Sized + $tr> $tr for &'a T { |
1349 | fn fmt(&self, f: &mut Formatter) -> Result { $tr::fmt(&**self, f) } | |
1350 | } | |
85aaf69f | 1351 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1352 | impl<'a, T: ?Sized + $tr> $tr for &'a mut T { |
1353 | fn fmt(&self, f: &mut Formatter) -> Result { $tr::fmt(&**self, f) } | |
1354 | } | |
1355 | )* | |
1356 | } | |
1357 | } | |
1358 | ||
85aaf69f | 1359 | fmt_refs! { Debug, Display, Octal, Binary, LowerHex, UpperHex, LowerExp, UpperExp } |
1a4d82fc | 1360 | |
c30ab7b3 | 1361 | #[unstable(feature = "never_type_impls", issue = "35121")] |
9e0c209e SL |
1362 | impl Debug for ! { |
1363 | fn fmt(&self, _: &mut Formatter) -> Result { | |
1364 | *self | |
5bcae85e SL |
1365 | } |
1366 | } | |
1367 | ||
c30ab7b3 | 1368 | #[unstable(feature = "never_type_impls", issue = "35121")] |
9e0c209e SL |
1369 | impl Display for ! { |
1370 | fn fmt(&self, _: &mut Formatter) -> Result { | |
1371 | *self | |
1372 | } | |
1373 | } | |
5bcae85e | 1374 | |
85aaf69f SL |
1375 | #[stable(feature = "rust1", since = "1.0.0")] |
1376 | impl Debug for bool { | |
1a4d82fc | 1377 | fn fmt(&self, f: &mut Formatter) -> Result { |
85aaf69f | 1378 | Display::fmt(self, f) |
1a4d82fc JJ |
1379 | } |
1380 | } | |
1381 | ||
85aaf69f SL |
1382 | #[stable(feature = "rust1", since = "1.0.0")] |
1383 | impl Display for bool { | |
1a4d82fc | 1384 | fn fmt(&self, f: &mut Formatter) -> Result { |
85aaf69f | 1385 | Display::fmt(if *self { "true" } else { "false" }, f) |
1a4d82fc JJ |
1386 | } |
1387 | } | |
1388 | ||
85aaf69f SL |
1389 | #[stable(feature = "rust1", since = "1.0.0")] |
1390 | impl Debug for str { | |
1a4d82fc | 1391 | fn fmt(&self, f: &mut Formatter) -> Result { |
54a0048b | 1392 | f.write_char('"')?; |
b039eaaf SL |
1393 | let mut from = 0; |
1394 | for (i, c) in self.char_indices() { | |
5bcae85e | 1395 | let esc = c.escape_debug(); |
b039eaaf | 1396 | // If char needs escaping, flush backlog so far and write, else skip |
3157f602 | 1397 | if esc.len() != 1 { |
54a0048b | 1398 | f.write_str(&self[from..i])?; |
b039eaaf | 1399 | for c in esc { |
54a0048b | 1400 | f.write_char(c)?; |
b039eaaf SL |
1401 | } |
1402 | from = i + c.len_utf8(); | |
1403 | } | |
1a4d82fc | 1404 | } |
54a0048b | 1405 | f.write_str(&self[from..])?; |
b039eaaf | 1406 | f.write_char('"') |
1a4d82fc JJ |
1407 | } |
1408 | } | |
1409 | ||
85aaf69f SL |
1410 | #[stable(feature = "rust1", since = "1.0.0")] |
1411 | impl Display for str { | |
1a4d82fc JJ |
1412 | fn fmt(&self, f: &mut Formatter) -> Result { |
1413 | f.pad(self) | |
1414 | } | |
1415 | } | |
1416 | ||
85aaf69f SL |
1417 | #[stable(feature = "rust1", since = "1.0.0")] |
1418 | impl Debug for char { | |
1a4d82fc | 1419 | fn fmt(&self, f: &mut Formatter) -> Result { |
54a0048b | 1420 | f.write_char('\'')?; |
5bcae85e | 1421 | for c in self.escape_debug() { |
54a0048b | 1422 | f.write_char(c)? |
1a4d82fc | 1423 | } |
b039eaaf | 1424 | f.write_char('\'') |
1a4d82fc JJ |
1425 | } |
1426 | } | |
1427 | ||
85aaf69f SL |
1428 | #[stable(feature = "rust1", since = "1.0.0")] |
1429 | impl Display for char { | |
1a4d82fc | 1430 | fn fmt(&self, f: &mut Formatter) -> Result { |
62682a34 SL |
1431 | if f.width.is_none() && f.precision.is_none() { |
1432 | f.write_char(*self) | |
1433 | } else { | |
c30ab7b3 | 1434 | f.pad(self.encode_utf8(&mut [0; 4])) |
62682a34 | 1435 | } |
1a4d82fc JJ |
1436 | } |
1437 | } | |
1438 | ||
85aaf69f | 1439 | #[stable(feature = "rust1", since = "1.0.0")] |
7453a54e | 1440 | impl<T: ?Sized> Pointer for *const T { |
1a4d82fc | 1441 | fn fmt(&self, f: &mut Formatter) -> Result { |
9346a6ac AL |
1442 | let old_width = f.width; |
1443 | let old_flags = f.flags; | |
1444 | ||
1445 | // The alternate flag is already treated by LowerHex as being special- | |
1446 | // it denotes whether to prefix with 0x. We use it to work out whether | |
1447 | // or not to zero extend, and then unconditionally set it to get the | |
1448 | // prefix. | |
b039eaaf | 1449 | if f.alternate() { |
9346a6ac AL |
1450 | f.flags |= 1 << (FlagV1::SignAwareZeroPad as u32); |
1451 | ||
1452 | if let None = f.width { | |
9cc50fc6 | 1453 | f.width = Some(((mem::size_of::<usize>() * 8) / 4) + 2); |
9346a6ac AL |
1454 | } |
1455 | } | |
c34b1796 | 1456 | f.flags |= 1 << (FlagV1::Alternate as u32); |
9346a6ac | 1457 | |
7453a54e | 1458 | let ret = LowerHex::fmt(&(*self as *const () as usize), f); |
9346a6ac AL |
1459 | |
1460 | f.width = old_width; | |
1461 | f.flags = old_flags; | |
1462 | ||
1a4d82fc JJ |
1463 | ret |
1464 | } | |
1465 | } | |
1466 | ||
85aaf69f | 1467 | #[stable(feature = "rust1", since = "1.0.0")] |
7453a54e | 1468 | impl<T: ?Sized> Pointer for *mut T { |
1a4d82fc JJ |
1469 | fn fmt(&self, f: &mut Formatter) -> Result { |
1470 | Pointer::fmt(&(*self as *const T), f) | |
1471 | } | |
1472 | } | |
1473 | ||
85aaf69f | 1474 | #[stable(feature = "rust1", since = "1.0.0")] |
7453a54e | 1475 | impl<'a, T: ?Sized> Pointer for &'a T { |
1a4d82fc JJ |
1476 | fn fmt(&self, f: &mut Formatter) -> Result { |
1477 | Pointer::fmt(&(*self as *const T), f) | |
1478 | } | |
1479 | } | |
1480 | ||
85aaf69f | 1481 | #[stable(feature = "rust1", since = "1.0.0")] |
7453a54e | 1482 | impl<'a, T: ?Sized> Pointer for &'a mut T { |
1a4d82fc JJ |
1483 | fn fmt(&self, f: &mut Formatter) -> Result { |
1484 | Pointer::fmt(&(&**self as *const T), f) | |
1485 | } | |
1486 | } | |
1487 | ||
9346a6ac | 1488 | // Common code of floating point Debug and Display. |
d9579d0f AL |
1489 | fn float_to_decimal_common<T>(fmt: &mut Formatter, num: &T, negative_zero: bool) -> Result |
1490 | where T: flt2dec::DecodableFloat | |
1491 | { | |
b039eaaf | 1492 | let force_sign = fmt.sign_plus(); |
d9579d0f AL |
1493 | let sign = match (force_sign, negative_zero) { |
1494 | (false, false) => flt2dec::Sign::Minus, | |
1495 | (false, true) => flt2dec::Sign::MinusRaw, | |
1496 | (true, false) => flt2dec::Sign::MinusPlus, | |
1497 | (true, true) => flt2dec::Sign::MinusPlusRaw, | |
1498 | }; | |
1499 | ||
1500 | let mut buf = [0; 1024]; // enough for f32 and f64 | |
1501 | let mut parts = [flt2dec::Part::Zero(0); 16]; | |
1502 | let formatted = if let Some(precision) = fmt.precision { | |
1503 | flt2dec::to_exact_fixed_str(flt2dec::strategy::grisu::format_exact, *num, sign, | |
1504 | precision, false, &mut buf, &mut parts) | |
1505 | } else { | |
1506 | flt2dec::to_shortest_str(flt2dec::strategy::grisu::format_shortest, *num, sign, | |
1507 | 0, false, &mut buf, &mut parts) | |
1508 | }; | |
1509 | fmt.pad_formatted_parts(&formatted) | |
1510 | } | |
1511 | ||
1512 | // Common code of floating point LowerExp and UpperExp. | |
1513 | fn float_to_exponential_common<T>(fmt: &mut Formatter, num: &T, upper: bool) -> Result | |
1514 | where T: flt2dec::DecodableFloat | |
1515 | { | |
b039eaaf | 1516 | let force_sign = fmt.sign_plus(); |
d9579d0f AL |
1517 | let sign = match force_sign { |
1518 | false => flt2dec::Sign::Minus, | |
1519 | true => flt2dec::Sign::MinusPlus, | |
1520 | }; | |
1521 | ||
1522 | let mut buf = [0; 1024]; // enough for f32 and f64 | |
1523 | let mut parts = [flt2dec::Part::Zero(0); 16]; | |
1524 | let formatted = if let Some(precision) = fmt.precision { | |
1525 | // 1 integral digit + `precision` fractional digits = `precision + 1` total digits | |
1526 | flt2dec::to_exact_exp_str(flt2dec::strategy::grisu::format_exact, *num, sign, | |
1527 | precision + 1, upper, &mut buf, &mut parts) | |
1528 | } else { | |
1529 | flt2dec::to_shortest_exp_str(flt2dec::strategy::grisu::format_shortest, *num, sign, | |
1530 | (0, 0), upper, &mut buf, &mut parts) | |
9346a6ac | 1531 | }; |
d9579d0f | 1532 | fmt.pad_formatted_parts(&formatted) |
9346a6ac AL |
1533 | } |
1534 | ||
1a4d82fc JJ |
1535 | macro_rules! floating { ($ty:ident) => { |
1536 | ||
85aaf69f SL |
1537 | #[stable(feature = "rust1", since = "1.0.0")] |
1538 | impl Debug for $ty { | |
1a4d82fc | 1539 | fn fmt(&self, fmt: &mut Formatter) -> Result { |
d9579d0f | 1540 | float_to_decimal_common(fmt, self, true) |
1a4d82fc JJ |
1541 | } |
1542 | } | |
1543 | ||
85aaf69f SL |
1544 | #[stable(feature = "rust1", since = "1.0.0")] |
1545 | impl Display for $ty { | |
1a4d82fc | 1546 | fn fmt(&self, fmt: &mut Formatter) -> Result { |
d9579d0f | 1547 | float_to_decimal_common(fmt, self, false) |
1a4d82fc JJ |
1548 | } |
1549 | } | |
1550 | ||
85aaf69f | 1551 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1552 | impl LowerExp for $ty { |
1553 | fn fmt(&self, fmt: &mut Formatter) -> Result { | |
d9579d0f | 1554 | float_to_exponential_common(fmt, self, false) |
1a4d82fc JJ |
1555 | } |
1556 | } | |
1557 | ||
85aaf69f | 1558 | #[stable(feature = "rust1", since = "1.0.0")] |
1a4d82fc JJ |
1559 | impl UpperExp for $ty { |
1560 | fn fmt(&self, fmt: &mut Formatter) -> Result { | |
d9579d0f | 1561 | float_to_exponential_common(fmt, self, true) |
1a4d82fc JJ |
1562 | } |
1563 | } | |
1564 | } } | |
1565 | floating! { f32 } | |
1566 | floating! { f64 } | |
1567 | ||
85aaf69f | 1568 | // Implementation of Display/Debug for various core types |
1a4d82fc | 1569 | |
85aaf69f | 1570 | #[stable(feature = "rust1", since = "1.0.0")] |
c30ab7b3 | 1571 | impl<T: ?Sized> Debug for *const T { |
1a4d82fc JJ |
1572 | fn fmt(&self, f: &mut Formatter) -> Result { Pointer::fmt(self, f) } |
1573 | } | |
85aaf69f | 1574 | #[stable(feature = "rust1", since = "1.0.0")] |
c30ab7b3 | 1575 | impl<T: ?Sized> Debug for *mut T { |
1a4d82fc JJ |
1576 | fn fmt(&self, f: &mut Formatter) -> Result { Pointer::fmt(self, f) } |
1577 | } | |
1578 | ||
1579 | macro_rules! peel { | |
1580 | ($name:ident, $($other:ident,)*) => (tuple! { $($other,)* }) | |
1581 | } | |
1582 | ||
1583 | macro_rules! tuple { | |
1584 | () => (); | |
1585 | ( $($name:ident,)+ ) => ( | |
85aaf69f SL |
1586 | #[stable(feature = "rust1", since = "1.0.0")] |
1587 | impl<$($name:Debug),*> Debug for ($($name,)*) { | |
9cc50fc6 | 1588 | #[allow(non_snake_case, unused_assignments, deprecated)] |
1a4d82fc | 1589 | fn fmt(&self, f: &mut Formatter) -> Result { |
c1a9b12d | 1590 | let mut builder = f.debug_tuple(""); |
1a4d82fc | 1591 | let ($(ref $name,)*) = *self; |
1a4d82fc | 1592 | $( |
c1a9b12d | 1593 | builder.field($name); |
1a4d82fc | 1594 | )* |
c1a9b12d | 1595 | |
c1a9b12d | 1596 | builder.finish() |
1a4d82fc JJ |
1597 | } |
1598 | } | |
1599 | peel! { $($name,)* } | |
1600 | ) | |
1601 | } | |
1602 | ||
1603 | tuple! { T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, } | |
1604 | ||
85aaf69f SL |
1605 | #[stable(feature = "rust1", since = "1.0.0")] |
1606 | impl<T: Debug> Debug for [T] { | |
1a4d82fc | 1607 | fn fmt(&self, f: &mut Formatter) -> Result { |
62682a34 | 1608 | f.debug_list().entries(self.iter()).finish() |
1a4d82fc JJ |
1609 | } |
1610 | } | |
1611 | ||
85aaf69f SL |
1612 | #[stable(feature = "rust1", since = "1.0.0")] |
1613 | impl Debug for () { | |
1a4d82fc JJ |
1614 | fn fmt(&self, f: &mut Formatter) -> Result { |
1615 | f.pad("()") | |
1616 | } | |
1617 | } | |
92a42be0 | 1618 | #[stable(feature = "rust1", since = "1.0.0")] |
9cc50fc6 | 1619 | impl<T: ?Sized> Debug for PhantomData<T> { |
1a4d82fc | 1620 | fn fmt(&self, f: &mut Formatter) -> Result { |
85aaf69f | 1621 | f.pad("PhantomData") |
1a4d82fc JJ |
1622 | } |
1623 | } | |
1624 | ||
85aaf69f SL |
1625 | #[stable(feature = "rust1", since = "1.0.0")] |
1626 | impl<T: Copy + Debug> Debug for Cell<T> { | |
1a4d82fc | 1627 | fn fmt(&self, f: &mut Formatter) -> Result { |
54a0048b SL |
1628 | f.debug_struct("Cell") |
1629 | .field("value", &self.get()) | |
1630 | .finish() | |
1a4d82fc JJ |
1631 | } |
1632 | } | |
1633 | ||
85aaf69f | 1634 | #[stable(feature = "rust1", since = "1.0.0")] |
d9579d0f | 1635 | impl<T: ?Sized + Debug> Debug for RefCell<T> { |
1a4d82fc | 1636 | fn fmt(&self, f: &mut Formatter) -> Result { |
476ff2be SL |
1637 | match self.try_borrow() { |
1638 | Ok(borrow) => { | |
54a0048b | 1639 | f.debug_struct("RefCell") |
476ff2be | 1640 | .field("value", &borrow) |
54a0048b SL |
1641 | .finish() |
1642 | } | |
476ff2be | 1643 | Err(_) => { |
54a0048b SL |
1644 | f.debug_struct("RefCell") |
1645 | .field("value", &"<borrowed>") | |
1646 | .finish() | |
85aaf69f | 1647 | } |
85aaf69f | 1648 | } |
1a4d82fc JJ |
1649 | } |
1650 | } | |
1651 | ||
85aaf69f | 1652 | #[stable(feature = "rust1", since = "1.0.0")] |
d9579d0f | 1653 | impl<'b, T: ?Sized + Debug> Debug for Ref<'b, T> { |
1a4d82fc | 1654 | fn fmt(&self, f: &mut Formatter) -> Result { |
85aaf69f | 1655 | Debug::fmt(&**self, f) |
1a4d82fc JJ |
1656 | } |
1657 | } | |
1658 | ||
85aaf69f | 1659 | #[stable(feature = "rust1", since = "1.0.0")] |
d9579d0f | 1660 | impl<'b, T: ?Sized + Debug> Debug for RefMut<'b, T> { |
1a4d82fc | 1661 | fn fmt(&self, f: &mut Formatter) -> Result { |
85aaf69f | 1662 | Debug::fmt(&*(self.deref()), f) |
1a4d82fc JJ |
1663 | } |
1664 | } | |
1665 | ||
54a0048b SL |
1666 | #[stable(feature = "core_impl_debug", since = "1.9.0")] |
1667 | impl<T: ?Sized + Debug> Debug for UnsafeCell<T> { | |
1668 | fn fmt(&self, f: &mut Formatter) -> Result { | |
1669 | f.pad("UnsafeCell") | |
1670 | } | |
1671 | } | |
1672 | ||
1a4d82fc JJ |
1673 | // If you expected tests to be here, look instead at the run-pass/ifmt.rs test, |
1674 | // it's a lot easier than creating all of the rt::Piece structures here. |