1 // Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
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.
11 //! String manipulation
13 //! For more details, see std::str
15 #![stable(feature = "rust1", since = "1.0.0")]
17 use self::pattern::Pattern;
18 use self::pattern::{Searcher, ReverseSearcher, DoubleEndedSearcher};
22 use iter::{Map, Cloned, FusedIterator};
28 /// A trait to abstract the idea of creating a new instance of a type from a
31 /// `FromStr`'s [`from_str()`] method is often used implicitly, through
32 /// [`str`]'s [`parse()`] method. See [`parse()`]'s documentation for examples.
34 /// [`from_str()`]: #tymethod.from_str
35 /// [`str`]: ../../std/primitive.str.html
36 /// [`parse()`]: ../../std/primitive.str.html#method.parse
37 #[stable(feature = "rust1", since = "1.0.0")]
38 pub trait FromStr: Sized {
39 /// The associated error which can be returned from parsing.
40 #[stable(feature = "rust1", since = "1.0.0")]
43 /// Parses a string `s` to return a value of this type.
45 /// If parsing succeeds, return the value inside `Ok`, otherwise
46 /// when the string is ill-formatted return an error specific to the
47 /// inside `Err`. The error type is specific to implementation of the trait.
51 /// Basic usage with [`i32`][ithirtytwo], a type that implements `FromStr`:
53 /// [ithirtytwo]: ../../std/primitive.i32.html
56 /// use std::str::FromStr;
59 /// let x = i32::from_str(s).unwrap();
63 #[stable(feature = "rust1", since = "1.0.0")]
64 fn from_str(s: &str) -> Result<Self, Self::Err>;
67 #[stable(feature = "rust1", since = "1.0.0")]
68 impl FromStr for bool {
69 type Err = ParseBoolError;
71 /// Parse a `bool` from a string.
73 /// Yields a `Result<bool, ParseBoolError>`, because `s` may or may not
74 /// actually be parseable.
79 /// use std::str::FromStr;
81 /// assert_eq!(FromStr::from_str("true"), Ok(true));
82 /// assert_eq!(FromStr::from_str("false"), Ok(false));
83 /// assert!(<bool as FromStr>::from_str("not even a boolean").is_err());
86 /// Note, in many cases, the `.parse()` method on `str` is more proper.
89 /// assert_eq!("true".parse(), Ok(true));
90 /// assert_eq!("false".parse(), Ok(false));
91 /// assert!("not even a boolean".parse::<bool>().is_err());
94 fn from_str(s: &str) -> Result<bool, ParseBoolError> {
98 _ => Err(ParseBoolError { _priv: () }),
103 /// An error returned when parsing a `bool` from a string fails.
104 #[derive(Debug, Clone, PartialEq, Eq)]
105 #[stable(feature = "rust1", since = "1.0.0")]
106 pub struct ParseBoolError { _priv: () }
108 #[stable(feature = "rust1", since = "1.0.0")]
109 impl fmt::Display for ParseBoolError {
110 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
111 "provided string was not `true` or `false`".fmt(f)
116 Section: Creating a string
119 /// Errors which can occur when attempting to interpret a sequence of `u8`
122 /// As such, the `from_utf8` family of functions and methods for both `String`s
123 /// and `&str`s make use of this error, for example.
124 #[derive(Copy, Eq, PartialEq, Clone, Debug)]
125 #[stable(feature = "rust1", since = "1.0.0")]
126 pub struct Utf8Error {
131 /// Returns the index in the given string up to which valid UTF-8 was
134 /// It is the maximum index such that `from_utf8(input[..index])`
135 /// would return `Some(_)`.
144 /// // some invalid bytes, in a vector
145 /// let sparkle_heart = vec![0, 159, 146, 150];
147 /// // std::str::from_utf8 returns a Utf8Error
148 /// let error = str::from_utf8(&sparkle_heart).unwrap_err();
150 /// // the second byte is invalid here
151 /// assert_eq!(1, error.valid_up_to());
153 #[stable(feature = "utf8_error", since = "1.5.0")]
154 pub fn valid_up_to(&self) -> usize { self.valid_up_to }
157 /// Converts a slice of bytes to a string slice.
159 /// A string slice (`&str`) is made of bytes (`u8`), and a byte slice (`&[u8]`)
160 /// is made of bytes, so this function converts between the two. Not all byte
161 /// slices are valid string slices, however: `&str` requires that it is valid
162 /// UTF-8. `from_utf8()` checks to ensure that the bytes are valid UTF-8, and
163 /// then does the conversion.
165 /// If you are sure that the byte slice is valid UTF-8, and you don't want to
166 /// incur the overhead of the validity check, there is an unsafe version of
167 /// this function, [`from_utf8_unchecked()`][fromutf8u], which has the same
168 /// behavior but skips the check.
170 /// [fromutf8u]: fn.from_utf8_unchecked.html
172 /// If you need a `String` instead of a `&str`, consider
173 /// [`String::from_utf8()`][string].
175 /// [string]: ../../std/string/struct.String.html#method.from_utf8
177 /// Because you can stack-allocate a `[u8; N]`, and you can take a `&[u8]` of
178 /// it, this function is one way to have a stack-allocated string. There is
179 /// an example of this in the examples section below.
183 /// Returns `Err` if the slice is not UTF-8 with a description as to why the
184 /// provided slice is not UTF-8.
193 /// // some bytes, in a vector
194 /// let sparkle_heart = vec![240, 159, 146, 150];
196 /// // We know these bytes are valid, so just use `unwrap()`.
197 /// let sparkle_heart = str::from_utf8(&sparkle_heart).unwrap();
199 /// assert_eq!("💖", sparkle_heart);
207 /// // some invalid bytes, in a vector
208 /// let sparkle_heart = vec![0, 159, 146, 150];
210 /// assert!(str::from_utf8(&sparkle_heart).is_err());
213 /// See the docs for [`Utf8Error`][error] for more details on the kinds of
214 /// errors that can be returned.
216 /// [error]: struct.Utf8Error.html
218 /// A "stack allocated string":
223 /// // some bytes, in a stack-allocated array
224 /// let sparkle_heart = [240, 159, 146, 150];
226 /// // We know these bytes are valid, so just use `unwrap()`.
227 /// let sparkle_heart = str::from_utf8(&sparkle_heart).unwrap();
229 /// assert_eq!("💖", sparkle_heart);
231 #[stable(feature = "rust1", since = "1.0.0")]
232 pub fn from_utf8(v: &[u8]) -> Result<&str, Utf8Error> {
233 run_utf8_validation(v)?;
234 Ok(unsafe { from_utf8_unchecked(v) })
237 /// Forms a str from a pointer and a length.
239 /// The `len` argument is the number of bytes in the string.
243 /// This function is unsafe as there is no guarantee that the given pointer is
244 /// valid for `len` bytes, nor whether the lifetime inferred is a suitable
245 /// lifetime for the returned str.
247 /// The data must be valid UTF-8
249 /// `p` must be non-null, even for zero-length str.
253 /// The lifetime for the returned str is inferred from its usage. To
254 /// prevent accidental misuse, it's suggested to tie the lifetime to whichever
255 /// source lifetime is safe in the context, such as by providing a helper
256 /// function taking the lifetime of a host value for the str, or by explicit
258 /// Performs the same functionality as `from_raw_parts`, except that a mutable
261 unsafe fn from_raw_parts_mut<'a>(p: *mut u8, len: usize) -> &'a mut str {
262 mem::transmute::<&mut [u8], &mut str>(slice::from_raw_parts_mut(p, len))
265 /// Converts a slice of bytes to a string slice without checking
266 /// that the string contains valid UTF-8.
268 /// See the safe version, [`from_utf8()`][fromutf8], for more information.
270 /// [fromutf8]: fn.from_utf8.html
274 /// This function is unsafe because it does not check that the bytes passed to
275 /// it are valid UTF-8. If this constraint is violated, undefined behavior
276 /// results, as the rest of Rust assumes that `&str`s are valid UTF-8.
285 /// // some bytes, in a vector
286 /// let sparkle_heart = vec![240, 159, 146, 150];
288 /// let sparkle_heart = unsafe {
289 /// str::from_utf8_unchecked(&sparkle_heart)
292 /// assert_eq!("💖", sparkle_heart);
295 #[stable(feature = "rust1", since = "1.0.0")]
296 pub unsafe fn from_utf8_unchecked(v: &[u8]) -> &str {
300 #[stable(feature = "rust1", since = "1.0.0")]
301 impl fmt::Display for Utf8Error {
302 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
303 write!(f, "invalid utf-8: invalid byte near index {}", self.valid_up_to)
311 /// Iterator for the char (representing *Unicode Scalar Values*) of a string
313 /// Created with the method [`chars()`].
315 /// [`chars()`]: ../../std/primitive.str.html#method.chars
316 #[derive(Clone, Debug)]
317 #[stable(feature = "rust1", since = "1.0.0")]
318 pub struct Chars<'a> {
319 iter: slice::Iter<'a, u8>
322 /// Return the initial codepoint accumulator for the first byte.
323 /// The first byte is special, only want bottom 5 bits for width 2, 4 bits
324 /// for width 3, and 3 bits for width 4.
326 fn utf8_first_byte(byte: u8, width: u32) -> u32 { (byte & (0x7F >> width)) as u32 }
328 /// Return the value of `ch` updated with continuation byte `byte`.
330 fn utf8_acc_cont_byte(ch: u32, byte: u8) -> u32 { (ch << 6) | (byte & CONT_MASK) as u32 }
332 /// Checks whether the byte is a UTF-8 continuation byte (i.e. starts with the
335 fn utf8_is_cont_byte(byte: u8) -> bool { (byte & !CONT_MASK) == TAG_CONT_U8 }
338 fn unwrap_or_0(opt: Option<&u8>) -> u8 {
345 /// Reads the next code point out of a byte iterator (assuming a
346 /// UTF-8-like encoding).
347 #[unstable(feature = "str_internals", issue = "0")]
349 pub fn next_code_point<'a, I: Iterator<Item = &'a u8>>(bytes: &mut I) -> Option<u32> {
351 let x = match bytes.next() {
353 Some(&next_byte) if next_byte < 128 => return Some(next_byte as u32),
354 Some(&next_byte) => next_byte,
357 // Multibyte case follows
358 // Decode from a byte combination out of: [[[x y] z] w]
359 // NOTE: Performance is sensitive to the exact formulation here
360 let init = utf8_first_byte(x, 2);
361 let y = unwrap_or_0(bytes.next());
362 let mut ch = utf8_acc_cont_byte(init, y);
365 // 5th bit in 0xE0 .. 0xEF is always clear, so `init` is still valid
366 let z = unwrap_or_0(bytes.next());
367 let y_z = utf8_acc_cont_byte((y & CONT_MASK) as u32, z);
368 ch = init << 12 | y_z;
371 // use only the lower 3 bits of `init`
372 let w = unwrap_or_0(bytes.next());
373 ch = (init & 7) << 18 | utf8_acc_cont_byte(y_z, w);
380 /// Reads the last code point out of a byte iterator (assuming a
381 /// UTF-8-like encoding).
383 fn next_code_point_reverse<'a, I>(bytes: &mut I) -> Option<u32>
384 where I: DoubleEndedIterator<Item = &'a u8>,
387 let w = match bytes.next_back() {
389 Some(&next_byte) if next_byte < 128 => return Some(next_byte as u32),
390 Some(&back_byte) => back_byte,
393 // Multibyte case follows
394 // Decode from a byte combination out of: [x [y [z w]]]
396 let z = unwrap_or_0(bytes.next_back());
397 ch = utf8_first_byte(z, 2);
398 if utf8_is_cont_byte(z) {
399 let y = unwrap_or_0(bytes.next_back());
400 ch = utf8_first_byte(y, 3);
401 if utf8_is_cont_byte(y) {
402 let x = unwrap_or_0(bytes.next_back());
403 ch = utf8_first_byte(x, 4);
404 ch = utf8_acc_cont_byte(ch, y);
406 ch = utf8_acc_cont_byte(ch, z);
408 ch = utf8_acc_cont_byte(ch, w);
413 #[stable(feature = "rust1", since = "1.0.0")]
414 impl<'a> Iterator for Chars<'a> {
418 fn next(&mut self) -> Option<char> {
419 next_code_point(&mut self.iter).map(|ch| {
420 // str invariant says `ch` is a valid Unicode Scalar Value
422 char::from_u32_unchecked(ch)
428 fn size_hint(&self) -> (usize, Option<usize>) {
429 let len = self.iter.len();
430 // `(len + 3)` can't overflow, because we know that the `slice::Iter`
431 // belongs to a slice in memory which has a maximum length of
432 // `isize::MAX` (that's well below `usize::MAX`).
433 ((len + 3) / 4, Some(len))
437 #[stable(feature = "rust1", since = "1.0.0")]
438 impl<'a> DoubleEndedIterator for Chars<'a> {
440 fn next_back(&mut self) -> Option<char> {
441 next_code_point_reverse(&mut self.iter).map(|ch| {
442 // str invariant says `ch` is a valid Unicode Scalar Value
444 char::from_u32_unchecked(ch)
450 #[unstable(feature = "fused", issue = "35602")]
451 impl<'a> FusedIterator for Chars<'a> {}
454 /// View the underlying data as a subslice of the original data.
456 /// This has the same lifetime as the original slice, and so the
457 /// iterator can continue to be used while this exists.
462 /// let mut chars = "abc".chars();
464 /// assert_eq!(chars.as_str(), "abc");
466 /// assert_eq!(chars.as_str(), "bc");
469 /// assert_eq!(chars.as_str(), "");
471 #[stable(feature = "iter_to_slice", since = "1.4.0")]
473 pub fn as_str(&self) -> &'a str {
474 unsafe { from_utf8_unchecked(self.iter.as_slice()) }
478 /// Iterator for a string's characters and their byte offsets.
479 #[derive(Clone, Debug)]
480 #[stable(feature = "rust1", since = "1.0.0")]
481 pub struct CharIndices<'a> {
486 #[stable(feature = "rust1", since = "1.0.0")]
487 impl<'a> Iterator for CharIndices<'a> {
488 type Item = (usize, char);
491 fn next(&mut self) -> Option<(usize, char)> {
492 let pre_len = self.iter.iter.len();
493 match self.iter.next() {
496 let index = self.front_offset;
497 let len = self.iter.iter.len();
498 self.front_offset += pre_len - len;
505 fn size_hint(&self) -> (usize, Option<usize>) {
506 self.iter.size_hint()
510 #[stable(feature = "rust1", since = "1.0.0")]
511 impl<'a> DoubleEndedIterator for CharIndices<'a> {
513 fn next_back(&mut self) -> Option<(usize, char)> {
514 match self.iter.next_back() {
517 let index = self.front_offset + self.iter.iter.len();
524 #[unstable(feature = "fused", issue = "35602")]
525 impl<'a> FusedIterator for CharIndices<'a> {}
527 impl<'a> CharIndices<'a> {
528 /// View the underlying data as a subslice of the original data.
530 /// This has the same lifetime as the original slice, and so the
531 /// iterator can continue to be used while this exists.
532 #[stable(feature = "iter_to_slice", since = "1.4.0")]
534 pub fn as_str(&self) -> &'a str {
539 /// External iterator for a string's bytes.
540 /// Use with the `std::iter` module.
542 /// Created with the method [`bytes()`].
544 /// [`bytes()`]: ../../std/primitive.str.html#method.bytes
545 #[stable(feature = "rust1", since = "1.0.0")]
546 #[derive(Clone, Debug)]
547 pub struct Bytes<'a>(Cloned<slice::Iter<'a, u8>>);
549 #[stable(feature = "rust1", since = "1.0.0")]
550 impl<'a> Iterator for Bytes<'a> {
554 fn next(&mut self) -> Option<u8> {
559 fn size_hint(&self) -> (usize, Option<usize>) {
564 fn count(self) -> usize {
569 fn last(self) -> Option<Self::Item> {
574 fn nth(&mut self, n: usize) -> Option<Self::Item> {
579 #[stable(feature = "rust1", since = "1.0.0")]
580 impl<'a> DoubleEndedIterator for Bytes<'a> {
582 fn next_back(&mut self) -> Option<u8> {
587 #[stable(feature = "rust1", since = "1.0.0")]
588 impl<'a> ExactSizeIterator for Bytes<'a> {
590 fn len(&self) -> usize {
595 #[unstable(feature = "fused", issue = "35602")]
596 impl<'a> FusedIterator for Bytes<'a> {}
598 /// This macro generates a Clone impl for string pattern API
599 /// wrapper types of the form X<'a, P>
600 macro_rules! derive_pattern_clone {
601 (clone $t:ident with |$s:ident| $e:expr) => {
602 impl<'a, P: Pattern<'a>> Clone for $t<'a, P>
603 where P::Searcher: Clone
605 fn clone(&self) -> Self {
613 /// This macro generates two public iterator structs
614 /// wrapping a private internal one that makes use of the `Pattern` API.
616 /// For all patterns `P: Pattern<'a>` the following items will be
617 /// generated (generics omitted):
619 /// struct $forward_iterator($internal_iterator);
620 /// struct $reverse_iterator($internal_iterator);
622 /// impl Iterator for $forward_iterator
623 /// { /* internal ends up calling Searcher::next_match() */ }
625 /// impl DoubleEndedIterator for $forward_iterator
626 /// where P::Searcher: DoubleEndedSearcher
627 /// { /* internal ends up calling Searcher::next_match_back() */ }
629 /// impl Iterator for $reverse_iterator
630 /// where P::Searcher: ReverseSearcher
631 /// { /* internal ends up calling Searcher::next_match_back() */ }
633 /// impl DoubleEndedIterator for $reverse_iterator
634 /// where P::Searcher: DoubleEndedSearcher
635 /// { /* internal ends up calling Searcher::next_match() */ }
637 /// The internal one is defined outside the macro, and has almost the same
638 /// semantic as a DoubleEndedIterator by delegating to `pattern::Searcher` and
639 /// `pattern::ReverseSearcher` for both forward and reverse iteration.
641 /// "Almost", because a `Searcher` and a `ReverseSearcher` for a given
642 /// `Pattern` might not return the same elements, so actually implementing
643 /// `DoubleEndedIterator` for it would be incorrect.
644 /// (See the docs in `str::pattern` for more details)
646 /// However, the internal struct still represents a single ended iterator from
647 /// either end, and depending on pattern is also a valid double ended iterator,
648 /// so the two wrapper structs implement `Iterator`
649 /// and `DoubleEndedIterator` depending on the concrete pattern type, leading
650 /// to the complex impls seen above.
651 macro_rules! generate_pattern_iterators {
655 $(#[$forward_iterator_attribute:meta])*
656 struct $forward_iterator:ident;
660 $(#[$reverse_iterator_attribute:meta])*
661 struct $reverse_iterator:ident;
663 // Stability of all generated items
665 $(#[$common_stability_attribute:meta])*
667 // Internal almost-iterator that is being delegated to
669 $internal_iterator:ident yielding ($iterty:ty);
671 // Kind of delgation - either single ended or double ended
674 $(#[$forward_iterator_attribute])*
675 $(#[$common_stability_attribute])*
676 pub struct $forward_iterator<'a, P: Pattern<'a>>($internal_iterator<'a, P>);
678 $(#[$common_stability_attribute])*
679 impl<'a, P: Pattern<'a>> fmt::Debug for $forward_iterator<'a, P>
680 where P::Searcher: fmt::Debug
682 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
683 f.debug_tuple(stringify!($forward_iterator))
689 $(#[$common_stability_attribute])*
690 impl<'a, P: Pattern<'a>> Iterator for $forward_iterator<'a, P> {
694 fn next(&mut self) -> Option<$iterty> {
699 $(#[$common_stability_attribute])*
700 impl<'a, P: Pattern<'a>> Clone for $forward_iterator<'a, P>
701 where P::Searcher: Clone
703 fn clone(&self) -> Self {
704 $forward_iterator(self.0.clone())
708 $(#[$reverse_iterator_attribute])*
709 $(#[$common_stability_attribute])*
710 pub struct $reverse_iterator<'a, P: Pattern<'a>>($internal_iterator<'a, P>);
712 $(#[$common_stability_attribute])*
713 impl<'a, P: Pattern<'a>> fmt::Debug for $reverse_iterator<'a, P>
714 where P::Searcher: fmt::Debug
716 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
717 f.debug_tuple(stringify!($reverse_iterator))
723 $(#[$common_stability_attribute])*
724 impl<'a, P: Pattern<'a>> Iterator for $reverse_iterator<'a, P>
725 where P::Searcher: ReverseSearcher<'a>
730 fn next(&mut self) -> Option<$iterty> {
735 $(#[$common_stability_attribute])*
736 impl<'a, P: Pattern<'a>> Clone for $reverse_iterator<'a, P>
737 where P::Searcher: Clone
739 fn clone(&self) -> Self {
740 $reverse_iterator(self.0.clone())
744 #[unstable(feature = "fused", issue = "35602")]
745 impl<'a, P: Pattern<'a>> FusedIterator for $forward_iterator<'a, P> {}
747 #[unstable(feature = "fused", issue = "35602")]
748 impl<'a, P: Pattern<'a>> FusedIterator for $reverse_iterator<'a, P>
749 where P::Searcher: ReverseSearcher<'a> {}
751 generate_pattern_iterators!($($t)* with $(#[$common_stability_attribute])*,
753 $reverse_iterator, $iterty);
756 double ended; with $(#[$common_stability_attribute:meta])*,
757 $forward_iterator:ident,
758 $reverse_iterator:ident, $iterty:ty
760 $(#[$common_stability_attribute])*
761 impl<'a, P: Pattern<'a>> DoubleEndedIterator for $forward_iterator<'a, P>
762 where P::Searcher: DoubleEndedSearcher<'a>
765 fn next_back(&mut self) -> Option<$iterty> {
770 $(#[$common_stability_attribute])*
771 impl<'a, P: Pattern<'a>> DoubleEndedIterator for $reverse_iterator<'a, P>
772 where P::Searcher: DoubleEndedSearcher<'a>
775 fn next_back(&mut self) -> Option<$iterty> {
781 single ended; with $(#[$common_stability_attribute:meta])*,
782 $forward_iterator:ident,
783 $reverse_iterator:ident, $iterty:ty
787 derive_pattern_clone!{
789 with |s| SplitInternal { matcher: s.matcher.clone(), ..*s }
792 struct SplitInternal<'a, P: Pattern<'a>> {
795 matcher: P::Searcher,
796 allow_trailing_empty: bool,
800 impl<'a, P: Pattern<'a>> fmt::Debug for SplitInternal<'a, P> where P::Searcher: fmt::Debug {
801 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
802 f.debug_struct("SplitInternal")
803 .field("start", &self.start)
804 .field("end", &self.end)
805 .field("matcher", &self.matcher)
806 .field("allow_trailing_empty", &self.allow_trailing_empty)
807 .field("finished", &self.finished)
812 impl<'a, P: Pattern<'a>> SplitInternal<'a, P> {
814 fn get_end(&mut self) -> Option<&'a str> {
815 if !self.finished && (self.allow_trailing_empty || self.end - self.start > 0) {
816 self.finished = true;
818 let string = self.matcher.haystack().slice_unchecked(self.start, self.end);
827 fn next(&mut self) -> Option<&'a str> {
828 if self.finished { return None }
830 let haystack = self.matcher.haystack();
831 match self.matcher.next_match() {
832 Some((a, b)) => unsafe {
833 let elt = haystack.slice_unchecked(self.start, a);
837 None => self.get_end(),
842 fn next_back(&mut self) -> Option<&'a str>
843 where P::Searcher: ReverseSearcher<'a>
845 if self.finished { return None }
847 if !self.allow_trailing_empty {
848 self.allow_trailing_empty = true;
849 match self.next_back() {
850 Some(elt) if !elt.is_empty() => return Some(elt),
851 _ => if self.finished { return None }
855 let haystack = self.matcher.haystack();
856 match self.matcher.next_match_back() {
857 Some((a, b)) => unsafe {
858 let elt = haystack.slice_unchecked(b, self.end);
863 self.finished = true;
864 Some(haystack.slice_unchecked(self.start, self.end))
870 generate_pattern_iterators! {
872 /// Created with the method [`split()`].
874 /// [`split()`]: ../../std/primitive.str.html#method.split
877 /// Created with the method [`rsplit()`].
879 /// [`rsplit()`]: ../../std/primitive.str.html#method.rsplit
882 #[stable(feature = "rust1", since = "1.0.0")]
884 SplitInternal yielding (&'a str);
885 delegate double ended;
888 generate_pattern_iterators! {
890 /// Created with the method [`split_terminator()`].
892 /// [`split_terminator()`]: ../../std/primitive.str.html#method.split_terminator
893 struct SplitTerminator;
895 /// Created with the method [`rsplit_terminator()`].
897 /// [`rsplit_terminator()`]: ../../std/primitive.str.html#method.rsplit_terminator
898 struct RSplitTerminator;
900 #[stable(feature = "rust1", since = "1.0.0")]
902 SplitInternal yielding (&'a str);
903 delegate double ended;
906 derive_pattern_clone!{
908 with |s| SplitNInternal { iter: s.iter.clone(), ..*s }
911 struct SplitNInternal<'a, P: Pattern<'a>> {
912 iter: SplitInternal<'a, P>,
913 /// The number of splits remaining
917 impl<'a, P: Pattern<'a>> fmt::Debug for SplitNInternal<'a, P> where P::Searcher: fmt::Debug {
918 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
919 f.debug_struct("SplitNInternal")
920 .field("iter", &self.iter)
921 .field("count", &self.count)
926 impl<'a, P: Pattern<'a>> SplitNInternal<'a, P> {
928 fn next(&mut self) -> Option<&'a str> {
931 1 => { self.count = 0; self.iter.get_end() }
932 _ => { self.count -= 1; self.iter.next() }
937 fn next_back(&mut self) -> Option<&'a str>
938 where P::Searcher: ReverseSearcher<'a>
942 1 => { self.count = 0; self.iter.get_end() }
943 _ => { self.count -= 1; self.iter.next_back() }
948 generate_pattern_iterators! {
950 /// Created with the method [`splitn()`].
952 /// [`splitn()`]: ../../std/primitive.str.html#method.splitn
955 /// Created with the method [`rsplitn()`].
957 /// [`rsplitn()`]: ../../std/primitive.str.html#method.rsplitn
960 #[stable(feature = "rust1", since = "1.0.0")]
962 SplitNInternal yielding (&'a str);
963 delegate single ended;
966 derive_pattern_clone!{
967 clone MatchIndicesInternal
968 with |s| MatchIndicesInternal(s.0.clone())
971 struct MatchIndicesInternal<'a, P: Pattern<'a>>(P::Searcher);
973 impl<'a, P: Pattern<'a>> fmt::Debug for MatchIndicesInternal<'a, P> where P::Searcher: fmt::Debug {
974 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
975 f.debug_tuple("MatchIndicesInternal")
981 impl<'a, P: Pattern<'a>> MatchIndicesInternal<'a, P> {
983 fn next(&mut self) -> Option<(usize, &'a str)> {
984 self.0.next_match().map(|(start, end)| unsafe {
985 (start, self.0.haystack().slice_unchecked(start, end))
990 fn next_back(&mut self) -> Option<(usize, &'a str)>
991 where P::Searcher: ReverseSearcher<'a>
993 self.0.next_match_back().map(|(start, end)| unsafe {
994 (start, self.0.haystack().slice_unchecked(start, end))
999 generate_pattern_iterators! {
1001 /// Created with the method [`match_indices()`].
1003 /// [`match_indices()`]: ../../std/primitive.str.html#method.match_indices
1004 struct MatchIndices;
1006 /// Created with the method [`rmatch_indices()`].
1008 /// [`rmatch_indices()`]: ../../std/primitive.str.html#method.rmatch_indices
1009 struct RMatchIndices;
1011 #[stable(feature = "str_match_indices", since = "1.5.0")]
1013 MatchIndicesInternal yielding ((usize, &'a str));
1014 delegate double ended;
1017 derive_pattern_clone!{
1018 clone MatchesInternal
1019 with |s| MatchesInternal(s.0.clone())
1022 struct MatchesInternal<'a, P: Pattern<'a>>(P::Searcher);
1024 impl<'a, P: Pattern<'a>> fmt::Debug for MatchesInternal<'a, P> where P::Searcher: fmt::Debug {
1025 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
1026 f.debug_tuple("MatchesInternal")
1032 impl<'a, P: Pattern<'a>> MatchesInternal<'a, P> {
1034 fn next(&mut self) -> Option<&'a str> {
1035 self.0.next_match().map(|(a, b)| unsafe {
1036 // Indices are known to be on utf8 boundaries
1037 self.0.haystack().slice_unchecked(a, b)
1042 fn next_back(&mut self) -> Option<&'a str>
1043 where P::Searcher: ReverseSearcher<'a>
1045 self.0.next_match_back().map(|(a, b)| unsafe {
1046 // Indices are known to be on utf8 boundaries
1047 self.0.haystack().slice_unchecked(a, b)
1052 generate_pattern_iterators! {
1054 /// Created with the method [`matches()`].
1056 /// [`matches()`]: ../../std/primitive.str.html#method.matches
1059 /// Created with the method [`rmatches()`].
1061 /// [`rmatches()`]: ../../std/primitive.str.html#method.rmatches
1064 #[stable(feature = "str_matches", since = "1.2.0")]
1066 MatchesInternal yielding (&'a str);
1067 delegate double ended;
1070 /// Created with the method [`lines()`].
1072 /// [`lines()`]: ../../std/primitive.str.html#method.lines
1073 #[stable(feature = "rust1", since = "1.0.0")]
1074 #[derive(Clone, Debug)]
1075 pub struct Lines<'a>(Map<SplitTerminator<'a, char>, LinesAnyMap>);
1077 #[stable(feature = "rust1", since = "1.0.0")]
1078 impl<'a> Iterator for Lines<'a> {
1079 type Item = &'a str;
1082 fn next(&mut self) -> Option<&'a str> {
1087 fn size_hint(&self) -> (usize, Option<usize>) {
1092 #[stable(feature = "rust1", since = "1.0.0")]
1093 impl<'a> DoubleEndedIterator for Lines<'a> {
1095 fn next_back(&mut self) -> Option<&'a str> {
1100 #[unstable(feature = "fused", issue = "35602")]
1101 impl<'a> FusedIterator for Lines<'a> {}
1103 /// Created with the method [`lines_any()`].
1105 /// [`lines_any()`]: ../../std/primitive.str.html#method.lines_any
1106 #[stable(feature = "rust1", since = "1.0.0")]
1107 #[rustc_deprecated(since = "1.4.0", reason = "use lines()/Lines instead now")]
1108 #[derive(Clone, Debug)]
1109 #[allow(deprecated)]
1110 pub struct LinesAny<'a>(Lines<'a>);
1112 /// A nameable, cloneable fn type
1116 impl<'a> Fn<(&'a str,)> for LinesAnyMap {
1118 extern "rust-call" fn call(&self, (line,): (&'a str,)) -> &'a str {
1120 if l > 0 && line.as_bytes()[l - 1] == b'\r' { &line[0 .. l - 1] }
1125 impl<'a> FnMut<(&'a str,)> for LinesAnyMap {
1127 extern "rust-call" fn call_mut(&mut self, (line,): (&'a str,)) -> &'a str {
1128 Fn::call(&*self, (line,))
1132 impl<'a> FnOnce<(&'a str,)> for LinesAnyMap {
1133 type Output = &'a str;
1136 extern "rust-call" fn call_once(self, (line,): (&'a str,)) -> &'a str {
1137 Fn::call(&self, (line,))
1141 #[stable(feature = "rust1", since = "1.0.0")]
1142 #[allow(deprecated)]
1143 impl<'a> Iterator for LinesAny<'a> {
1144 type Item = &'a str;
1147 fn next(&mut self) -> Option<&'a str> {
1152 fn size_hint(&self) -> (usize, Option<usize>) {
1157 #[stable(feature = "rust1", since = "1.0.0")]
1158 #[allow(deprecated)]
1159 impl<'a> DoubleEndedIterator for LinesAny<'a> {
1161 fn next_back(&mut self) -> Option<&'a str> {
1166 #[unstable(feature = "fused", issue = "35602")]
1167 #[allow(deprecated)]
1168 impl<'a> FusedIterator for LinesAny<'a> {}
1171 Section: Comparing strings
1174 /// Bytewise slice equality
1175 /// NOTE: This function is (ab)used in rustc::middle::trans::_match
1176 /// to compare &[u8] byte slices that are not necessarily valid UTF-8.
1179 fn eq_slice(a: &str, b: &str) -> bool {
1180 a.as_bytes() == b.as_bytes()
1184 Section: UTF-8 validation
1187 // use truncation to fit u64 into usize
1188 const NONASCII_MASK: usize = 0x80808080_80808080u64 as usize;
1190 /// Return `true` if any byte in the word `x` is nonascii (>= 128).
1192 fn contains_nonascii(x: usize) -> bool {
1193 (x & NONASCII_MASK) != 0
1196 /// Walk through `iter` checking that it's a valid UTF-8 sequence,
1197 /// returning `true` in that case, or, if it is invalid, `false` with
1198 /// `iter` reset such that it is pointing at the first byte in the
1199 /// invalid sequence.
1201 fn run_utf8_validation(v: &[u8]) -> Result<(), Utf8Error> {
1204 while offset < len {
1205 let old_offset = offset;
1206 macro_rules! err { () => {{
1207 return Err(Utf8Error {
1208 valid_up_to: old_offset
1212 macro_rules! next { () => {{
1214 // we needed data, but there was none: error!
1221 let first = v[offset];
1223 let w = UTF8_CHAR_WIDTH[first as usize];
1224 let second = next!();
1225 // 2-byte encoding is for codepoints \u{0080} to \u{07ff}
1226 // first C2 80 last DF BF
1227 // 3-byte encoding is for codepoints \u{0800} to \u{ffff}
1228 // first E0 A0 80 last EF BF BF
1229 // excluding surrogates codepoints \u{d800} to \u{dfff}
1230 // ED A0 80 to ED BF BF
1231 // 4-byte encoding is for codepoints \u{1000}0 to \u{10ff}ff
1232 // first F0 90 80 80 last F4 8F BF BF
1234 // Use the UTF-8 syntax from the RFC
1236 // https://tools.ietf.org/html/rfc3629
1238 // UTF8-2 = %xC2-DF UTF8-tail
1239 // UTF8-3 = %xE0 %xA0-BF UTF8-tail / %xE1-EC 2( UTF8-tail ) /
1240 // %xED %x80-9F UTF8-tail / %xEE-EF 2( UTF8-tail )
1241 // UTF8-4 = %xF0 %x90-BF 2( UTF8-tail ) / %xF1-F3 3( UTF8-tail ) /
1242 // %xF4 %x80-8F 2( UTF8-tail )
1244 2 => if second & !CONT_MASK != TAG_CONT_U8 {err!()},
1246 match (first, second, next!() & !CONT_MASK) {
1247 (0xE0 , 0xA0 ... 0xBF, TAG_CONT_U8) |
1248 (0xE1 ... 0xEC, 0x80 ... 0xBF, TAG_CONT_U8) |
1249 (0xED , 0x80 ... 0x9F, TAG_CONT_U8) |
1250 (0xEE ... 0xEF, 0x80 ... 0xBF, TAG_CONT_U8) => {}
1255 match (first, second, next!() & !CONT_MASK, next!() & !CONT_MASK) {
1256 (0xF0 , 0x90 ... 0xBF, TAG_CONT_U8, TAG_CONT_U8) |
1257 (0xF1 ... 0xF3, 0x80 ... 0xBF, TAG_CONT_U8, TAG_CONT_U8) |
1258 (0xF4 , 0x80 ... 0x8F, TAG_CONT_U8, TAG_CONT_U8) => {}
1266 // Ascii case, try to skip forward quickly.
1267 // When the pointer is aligned, read 2 words of data per iteration
1268 // until we find a word containing a non-ascii byte.
1269 let usize_bytes = mem::size_of::<usize>();
1270 let bytes_per_iteration = 2 * usize_bytes;
1271 let ptr = v.as_ptr();
1272 let align = (ptr as usize + offset) & (usize_bytes - 1);
1274 if len >= bytes_per_iteration {
1275 while offset <= len - bytes_per_iteration {
1277 let u = *(ptr.offset(offset as isize) as *const usize);
1278 let v = *(ptr.offset((offset + usize_bytes) as isize) as *const usize);
1280 // break if there is a nonascii byte
1281 let zu = contains_nonascii(u);
1282 let zv = contains_nonascii(v);
1287 offset += bytes_per_iteration;
1290 // step from the point where the wordwise loop stopped
1291 while offset < len && v[offset] < 128 {
1303 // https://tools.ietf.org/html/rfc3629
1304 static UTF8_CHAR_WIDTH: [u8; 256] = [
1305 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
1306 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 0x1F
1307 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
1308 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 0x3F
1309 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
1310 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 0x5F
1311 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,
1312 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // 0x7F
1313 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
1314 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 0x9F
1315 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
1316 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 0xBF
1317 0,0,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
1318 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2, // 0xDF
1319 3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3, // 0xEF
1320 4,4,4,4,4,0,0,0,0,0,0,0,0,0,0,0, // 0xFF
1323 /// Mask of the value bits of a continuation byte
1324 const CONT_MASK: u8 = 0b0011_1111;
1325 /// Value of the tag bits (tag mask is !CONT_MASK) of a continuation byte
1326 const TAG_CONT_U8: u8 = 0b1000_0000;
1329 Section: Trait implementations
1337 #[stable(feature = "rust1", since = "1.0.0")]
1340 fn cmp(&self, other: &str) -> Ordering {
1341 self.as_bytes().cmp(other.as_bytes())
1345 #[stable(feature = "rust1", since = "1.0.0")]
1346 impl PartialEq for str {
1348 fn eq(&self, other: &str) -> bool {
1349 eq_slice(self, other)
1352 fn ne(&self, other: &str) -> bool { !(*self).eq(other) }
1355 #[stable(feature = "rust1", since = "1.0.0")]
1358 #[stable(feature = "rust1", since = "1.0.0")]
1359 impl PartialOrd for str {
1361 fn partial_cmp(&self, other: &str) -> Option<Ordering> {
1362 Some(self.cmp(other))
1366 /// Implements substring slicing with syntax `&self[begin .. end]`.
1368 /// Returns a slice of the given string from the byte range
1369 /// [`begin`..`end`).
1371 /// This operation is `O(1)`.
1375 /// Panics if `begin` or `end` does not point to the starting
1376 /// byte offset of a character (as defined by `is_char_boundary`).
1377 /// Requires that `begin <= end` and `end <= len` where `len` is the
1378 /// length of the string.
1383 /// let s = "Löwe 老虎 Léopard";
1384 /// assert_eq!(&s[0 .. 1], "L");
1386 /// assert_eq!(&s[1 .. 9], "öwe 老");
1388 /// // these will panic:
1389 /// // byte 2 lies within `ö`:
1392 /// // byte 8 lies within `老`
1395 /// // byte 100 is outside the string
1396 /// // &s[3 .. 100];
1398 #[stable(feature = "rust1", since = "1.0.0")]
1399 impl ops::Index<ops::Range<usize>> for str {
1402 fn index(&self, index: ops::Range<usize>) -> &str {
1403 // is_char_boundary checks that the index is in [0, .len()]
1404 if index.start <= index.end &&
1405 self.is_char_boundary(index.start) &&
1406 self.is_char_boundary(index.end) {
1407 unsafe { self.slice_unchecked(index.start, index.end) }
1409 super::slice_error_fail(self, index.start, index.end)
1414 /// Implements mutable substring slicing with syntax
1415 /// `&mut self[begin .. end]`.
1417 /// Returns a mutable slice of the given string from the byte range
1418 /// [`begin`..`end`).
1420 /// This operation is `O(1)`.
1424 /// Panics if `begin` or `end` does not point to the starting
1425 /// byte offset of a character (as defined by `is_char_boundary`).
1426 /// Requires that `begin <= end` and `end <= len` where `len` is the
1427 /// length of the string.
1428 #[stable(feature = "derefmut_for_string", since = "1.2.0")]
1429 impl ops::IndexMut<ops::Range<usize>> for str {
1431 fn index_mut(&mut self, index: ops::Range<usize>) -> &mut str {
1432 // is_char_boundary checks that the index is in [0, .len()]
1433 if index.start <= index.end &&
1434 self.is_char_boundary(index.start) &&
1435 self.is_char_boundary(index.end) {
1436 unsafe { self.slice_mut_unchecked(index.start, index.end) }
1438 super::slice_error_fail(self, index.start, index.end)
1443 /// Implements substring slicing with syntax `&self[.. end]`.
1445 /// Returns a slice of the string from the beginning to byte offset
1448 /// Equivalent to `&self[0 .. end]`.
1449 #[stable(feature = "rust1", since = "1.0.0")]
1450 impl ops::Index<ops::RangeTo<usize>> for str {
1454 fn index(&self, index: ops::RangeTo<usize>) -> &str {
1455 // is_char_boundary checks that the index is in [0, .len()]
1456 if self.is_char_boundary(index.end) {
1457 unsafe { self.slice_unchecked(0, index.end) }
1459 super::slice_error_fail(self, 0, index.end)
1464 /// Implements mutable substring slicing with syntax `&mut self[.. end]`.
1466 /// Returns a mutable slice of the string from the beginning to byte offset
1469 /// Equivalent to `&mut self[0 .. end]`.
1470 #[stable(feature = "derefmut_for_string", since = "1.2.0")]
1471 impl ops::IndexMut<ops::RangeTo<usize>> for str {
1473 fn index_mut(&mut self, index: ops::RangeTo<usize>) -> &mut str {
1474 // is_char_boundary checks that the index is in [0, .len()]
1475 if self.is_char_boundary(index.end) {
1476 unsafe { self.slice_mut_unchecked(0, index.end) }
1478 super::slice_error_fail(self, 0, index.end)
1483 /// Implements substring slicing with syntax `&self[begin ..]`.
1485 /// Returns a slice of the string from byte offset `begin`
1486 /// to the end of the string.
1488 /// Equivalent to `&self[begin .. len]`.
1489 #[stable(feature = "rust1", since = "1.0.0")]
1490 impl ops::Index<ops::RangeFrom<usize>> for str {
1494 fn index(&self, index: ops::RangeFrom<usize>) -> &str {
1495 // is_char_boundary checks that the index is in [0, .len()]
1496 if self.is_char_boundary(index.start) {
1497 unsafe { self.slice_unchecked(index.start, self.len()) }
1499 super::slice_error_fail(self, index.start, self.len())
1504 /// Implements mutable substring slicing with syntax `&mut self[begin ..]`.
1506 /// Returns a mutable slice of the string from byte offset `begin`
1507 /// to the end of the string.
1509 /// Equivalent to `&mut self[begin .. len]`.
1510 #[stable(feature = "derefmut_for_string", since = "1.2.0")]
1511 impl ops::IndexMut<ops::RangeFrom<usize>> for str {
1513 fn index_mut(&mut self, index: ops::RangeFrom<usize>) -> &mut str {
1514 // is_char_boundary checks that the index is in [0, .len()]
1515 if self.is_char_boundary(index.start) {
1516 let len = self.len();
1517 unsafe { self.slice_mut_unchecked(index.start, len) }
1519 super::slice_error_fail(self, index.start, self.len())
1524 /// Implements substring slicing with syntax `&self[..]`.
1526 /// Returns a slice of the whole string. This operation can
1529 /// Equivalent to `&self[0 .. len]`.
1530 #[stable(feature = "rust1", since = "1.0.0")]
1531 impl ops::Index<ops::RangeFull> for str {
1535 fn index(&self, _index: ops::RangeFull) -> &str {
1540 /// Implements mutable substring slicing with syntax `&mut self[..]`.
1542 /// Returns a mutable slice of the whole string. This operation can
1545 /// Equivalent to `&mut self[0 .. len]`.
1546 #[stable(feature = "derefmut_for_string", since = "1.2.0")]
1547 impl ops::IndexMut<ops::RangeFull> for str {
1549 fn index_mut(&mut self, _index: ops::RangeFull) -> &mut str {
1554 #[unstable(feature = "inclusive_range",
1555 reason = "recently added, follows RFC",
1557 impl ops::Index<ops::RangeInclusive<usize>> for str {
1561 fn index(&self, index: ops::RangeInclusive<usize>) -> &str {
1563 ops::RangeInclusive::Empty { .. } => "",
1564 ops::RangeInclusive::NonEmpty { end, .. } if end == usize::max_value() =>
1565 panic!("attempted to index slice up to maximum usize"),
1566 ops::RangeInclusive::NonEmpty { start, end } =>
1567 self.index(start .. end+1)
1571 #[unstable(feature = "inclusive_range",
1572 reason = "recently added, follows RFC",
1574 impl ops::Index<ops::RangeToInclusive<usize>> for str {
1578 fn index(&self, index: ops::RangeToInclusive<usize>) -> &str {
1579 self.index(0...index.end)
1583 #[unstable(feature = "inclusive_range",
1584 reason = "recently added, follows RFC",
1586 impl ops::IndexMut<ops::RangeInclusive<usize>> for str {
1588 fn index_mut(&mut self, index: ops::RangeInclusive<usize>) -> &mut str {
1590 ops::RangeInclusive::Empty { .. } => &mut self[0..0], // `&mut ""` doesn't work
1591 ops::RangeInclusive::NonEmpty { end, .. } if end == usize::max_value() =>
1592 panic!("attempted to index str up to maximum usize"),
1593 ops::RangeInclusive::NonEmpty { start, end } =>
1594 self.index_mut(start .. end+1)
1598 #[unstable(feature = "inclusive_range",
1599 reason = "recently added, follows RFC",
1601 impl ops::IndexMut<ops::RangeToInclusive<usize>> for str {
1603 fn index_mut(&mut self, index: ops::RangeToInclusive<usize>) -> &mut str {
1604 self.index_mut(0...index.end)
1609 /// Methods for string slices
1610 #[allow(missing_docs)]
1612 #[unstable(feature = "core_str_ext",
1613 reason = "stable interface provided by `impl str` in later crates",
1616 // NB there are no docs here are they're all located on the StrExt trait in
1617 // libcollections, not here.
1619 #[stable(feature = "core", since = "1.6.0")]
1620 fn contains<'a, P: Pattern<'a>>(&'a self, pat: P) -> bool;
1621 #[stable(feature = "core", since = "1.6.0")]
1622 fn chars(&self) -> Chars;
1623 #[stable(feature = "core", since = "1.6.0")]
1624 fn bytes(&self) -> Bytes;
1625 #[stable(feature = "core", since = "1.6.0")]
1626 fn char_indices(&self) -> CharIndices;
1627 #[stable(feature = "core", since = "1.6.0")]
1628 fn split<'a, P: Pattern<'a>>(&'a self, pat: P) -> Split<'a, P>;
1629 #[stable(feature = "core", since = "1.6.0")]
1630 fn rsplit<'a, P: Pattern<'a>>(&'a self, pat: P) -> RSplit<'a, P>
1631 where P::Searcher: ReverseSearcher<'a>;
1632 #[stable(feature = "core", since = "1.6.0")]
1633 fn splitn<'a, P: Pattern<'a>>(&'a self, count: usize, pat: P) -> SplitN<'a, P>;
1634 #[stable(feature = "core", since = "1.6.0")]
1635 fn rsplitn<'a, P: Pattern<'a>>(&'a self, count: usize, pat: P) -> RSplitN<'a, P>
1636 where P::Searcher: ReverseSearcher<'a>;
1637 #[stable(feature = "core", since = "1.6.0")]
1638 fn split_terminator<'a, P: Pattern<'a>>(&'a self, pat: P) -> SplitTerminator<'a, P>;
1639 #[stable(feature = "core", since = "1.6.0")]
1640 fn rsplit_terminator<'a, P: Pattern<'a>>(&'a self, pat: P) -> RSplitTerminator<'a, P>
1641 where P::Searcher: ReverseSearcher<'a>;
1642 #[stable(feature = "core", since = "1.6.0")]
1643 fn matches<'a, P: Pattern<'a>>(&'a self, pat: P) -> Matches<'a, P>;
1644 #[stable(feature = "core", since = "1.6.0")]
1645 fn rmatches<'a, P: Pattern<'a>>(&'a self, pat: P) -> RMatches<'a, P>
1646 where P::Searcher: ReverseSearcher<'a>;
1647 #[stable(feature = "core", since = "1.6.0")]
1648 fn match_indices<'a, P: Pattern<'a>>(&'a self, pat: P) -> MatchIndices<'a, P>;
1649 #[stable(feature = "core", since = "1.6.0")]
1650 fn rmatch_indices<'a, P: Pattern<'a>>(&'a self, pat: P) -> RMatchIndices<'a, P>
1651 where P::Searcher: ReverseSearcher<'a>;
1652 #[stable(feature = "core", since = "1.6.0")]
1653 fn lines(&self) -> Lines;
1654 #[stable(feature = "core", since = "1.6.0")]
1655 #[rustc_deprecated(since = "1.6.0", reason = "use lines() instead now")]
1656 #[allow(deprecated)]
1657 fn lines_any(&self) -> LinesAny;
1658 #[stable(feature = "core", since = "1.6.0")]
1659 unsafe fn slice_unchecked(&self, begin: usize, end: usize) -> &str;
1660 #[stable(feature = "core", since = "1.6.0")]
1661 unsafe fn slice_mut_unchecked(&mut self, begin: usize, end: usize) -> &mut str;
1662 #[stable(feature = "core", since = "1.6.0")]
1663 fn starts_with<'a, P: Pattern<'a>>(&'a self, pat: P) -> bool;
1664 #[stable(feature = "core", since = "1.6.0")]
1665 fn ends_with<'a, P: Pattern<'a>>(&'a self, pat: P) -> bool
1666 where P::Searcher: ReverseSearcher<'a>;
1667 #[stable(feature = "core", since = "1.6.0")]
1668 fn trim_matches<'a, P: Pattern<'a>>(&'a self, pat: P) -> &'a str
1669 where P::Searcher: DoubleEndedSearcher<'a>;
1670 #[stable(feature = "core", since = "1.6.0")]
1671 fn trim_left_matches<'a, P: Pattern<'a>>(&'a self, pat: P) -> &'a str;
1672 #[stable(feature = "core", since = "1.6.0")]
1673 fn trim_right_matches<'a, P: Pattern<'a>>(&'a self, pat: P) -> &'a str
1674 where P::Searcher: ReverseSearcher<'a>;
1675 #[stable(feature = "is_char_boundary", since = "1.9.0")]
1676 fn is_char_boundary(&self, index: usize) -> bool;
1677 #[stable(feature = "core", since = "1.6.0")]
1678 fn as_bytes(&self) -> &[u8];
1679 #[stable(feature = "core", since = "1.6.0")]
1680 fn find<'a, P: Pattern<'a>>(&'a self, pat: P) -> Option<usize>;
1681 #[stable(feature = "core", since = "1.6.0")]
1682 fn rfind<'a, P: Pattern<'a>>(&'a self, pat: P) -> Option<usize>
1683 where P::Searcher: ReverseSearcher<'a>;
1684 fn find_str<'a, P: Pattern<'a>>(&'a self, pat: P) -> Option<usize>;
1685 #[stable(feature = "core", since = "1.6.0")]
1686 fn split_at(&self, mid: usize) -> (&str, &str);
1687 #[stable(feature = "core", since = "1.6.0")]
1688 fn split_at_mut(&mut self, mid: usize) -> (&mut str, &mut str);
1689 #[stable(feature = "core", since = "1.6.0")]
1690 fn as_ptr(&self) -> *const u8;
1691 #[stable(feature = "core", since = "1.6.0")]
1692 fn len(&self) -> usize;
1693 #[stable(feature = "core", since = "1.6.0")]
1694 fn is_empty(&self) -> bool;
1695 #[stable(feature = "core", since = "1.6.0")]
1696 fn parse<T: FromStr>(&self) -> Result<T, T::Err>;
1699 // truncate `&str` to length at most equal to `max`
1700 // return `true` if it were truncated, and the new str.
1701 fn truncate_to_char_boundary(s: &str, mut max: usize) -> (bool, &str) {
1705 while !s.is_char_boundary(max) {
1714 fn slice_error_fail(s: &str, begin: usize, end: usize) -> ! {
1715 const MAX_DISPLAY_LENGTH: usize = 256;
1716 let (truncated, s) = truncate_to_char_boundary(s, MAX_DISPLAY_LENGTH);
1717 let ellipsis = if truncated { "[...]" } else { "" };
1719 assert!(begin <= end, "begin <= end ({} <= {}) when slicing `{}`{}",
1720 begin, end, s, ellipsis);
1721 panic!("index {} and/or {} in `{}`{} do not lie on character boundary",
1722 begin, end, s, ellipsis);
1725 #[stable(feature = "core", since = "1.6.0")]
1726 impl StrExt for str {
1728 fn contains<'a, P: Pattern<'a>>(&'a self, pat: P) -> bool {
1729 pat.is_contained_in(self)
1733 fn chars(&self) -> Chars {
1734 Chars{iter: self.as_bytes().iter()}
1738 fn bytes(&self) -> Bytes {
1739 Bytes(self.as_bytes().iter().cloned())
1743 fn char_indices(&self) -> CharIndices {
1744 CharIndices { front_offset: 0, iter: self.chars() }
1748 fn split<'a, P: Pattern<'a>>(&'a self, pat: P) -> Split<'a, P> {
1749 Split(SplitInternal {
1752 matcher: pat.into_searcher(self),
1753 allow_trailing_empty: true,
1759 fn rsplit<'a, P: Pattern<'a>>(&'a self, pat: P) -> RSplit<'a, P>
1760 where P::Searcher: ReverseSearcher<'a>
1762 RSplit(self.split(pat).0)
1766 fn splitn<'a, P: Pattern<'a>>(&'a self, count: usize, pat: P) -> SplitN<'a, P> {
1767 SplitN(SplitNInternal {
1768 iter: self.split(pat).0,
1774 fn rsplitn<'a, P: Pattern<'a>>(&'a self, count: usize, pat: P) -> RSplitN<'a, P>
1775 where P::Searcher: ReverseSearcher<'a>
1777 RSplitN(self.splitn(count, pat).0)
1781 fn split_terminator<'a, P: Pattern<'a>>(&'a self, pat: P) -> SplitTerminator<'a, P> {
1782 SplitTerminator(SplitInternal {
1783 allow_trailing_empty: false,
1789 fn rsplit_terminator<'a, P: Pattern<'a>>(&'a self, pat: P) -> RSplitTerminator<'a, P>
1790 where P::Searcher: ReverseSearcher<'a>
1792 RSplitTerminator(self.split_terminator(pat).0)
1796 fn matches<'a, P: Pattern<'a>>(&'a self, pat: P) -> Matches<'a, P> {
1797 Matches(MatchesInternal(pat.into_searcher(self)))
1801 fn rmatches<'a, P: Pattern<'a>>(&'a self, pat: P) -> RMatches<'a, P>
1802 where P::Searcher: ReverseSearcher<'a>
1804 RMatches(self.matches(pat).0)
1808 fn match_indices<'a, P: Pattern<'a>>(&'a self, pat: P) -> MatchIndices<'a, P> {
1809 MatchIndices(MatchIndicesInternal(pat.into_searcher(self)))
1813 fn rmatch_indices<'a, P: Pattern<'a>>(&'a self, pat: P) -> RMatchIndices<'a, P>
1814 where P::Searcher: ReverseSearcher<'a>
1816 RMatchIndices(self.match_indices(pat).0)
1819 fn lines(&self) -> Lines {
1820 Lines(self.split_terminator('\n').map(LinesAnyMap))
1824 #[allow(deprecated)]
1825 fn lines_any(&self) -> LinesAny {
1826 LinesAny(self.lines())
1830 unsafe fn slice_unchecked(&self, begin: usize, end: usize) -> &str {
1831 let ptr = self.as_ptr().offset(begin as isize);
1832 let len = end - begin;
1833 from_utf8_unchecked(slice::from_raw_parts(ptr, len))
1837 unsafe fn slice_mut_unchecked(&mut self, begin: usize, end: usize) -> &mut str {
1838 let ptr = self.as_ptr().offset(begin as isize);
1839 let len = end - begin;
1840 mem::transmute(slice::from_raw_parts_mut(ptr as *mut u8, len))
1844 fn starts_with<'a, P: Pattern<'a>>(&'a self, pat: P) -> bool {
1845 pat.is_prefix_of(self)
1849 fn ends_with<'a, P: Pattern<'a>>(&'a self, pat: P) -> bool
1850 where P::Searcher: ReverseSearcher<'a>
1852 pat.is_suffix_of(self)
1856 fn trim_matches<'a, P: Pattern<'a>>(&'a self, pat: P) -> &'a str
1857 where P::Searcher: DoubleEndedSearcher<'a>
1861 let mut matcher = pat.into_searcher(self);
1862 if let Some((a, b)) = matcher.next_reject() {
1864 j = b; // Remember earliest known match, correct it below if
1865 // last match is different
1867 if let Some((_, b)) = matcher.next_reject_back() {
1871 // Searcher is known to return valid indices
1872 self.slice_unchecked(i, j)
1877 fn trim_left_matches<'a, P: Pattern<'a>>(&'a self, pat: P) -> &'a str {
1878 let mut i = self.len();
1879 let mut matcher = pat.into_searcher(self);
1880 if let Some((a, _)) = matcher.next_reject() {
1884 // Searcher is known to return valid indices
1885 self.slice_unchecked(i, self.len())
1890 fn trim_right_matches<'a, P: Pattern<'a>>(&'a self, pat: P) -> &'a str
1891 where P::Searcher: ReverseSearcher<'a>
1894 let mut matcher = pat.into_searcher(self);
1895 if let Some((_, b)) = matcher.next_reject_back() {
1899 // Searcher is known to return valid indices
1900 self.slice_unchecked(0, j)
1905 fn is_char_boundary(&self, index: usize) -> bool {
1906 // 0 and len are always ok.
1907 // Test for 0 explicitly so that it can optimize out the check
1908 // easily and skip reading string data for that case.
1909 if index == 0 || index == self.len() { return true; }
1910 match self.as_bytes().get(index) {
1912 // This is bit magic equivalent to: b < 128 || b >= 192
1913 Some(&b) => (b as i8) >= -0x40,
1918 fn as_bytes(&self) -> &[u8] {
1919 unsafe { mem::transmute(self) }
1922 fn find<'a, P: Pattern<'a>>(&'a self, pat: P) -> Option<usize> {
1923 pat.into_searcher(self).next_match().map(|(i, _)| i)
1926 fn rfind<'a, P: Pattern<'a>>(&'a self, pat: P) -> Option<usize>
1927 where P::Searcher: ReverseSearcher<'a>
1929 pat.into_searcher(self).next_match_back().map(|(i, _)| i)
1932 fn find_str<'a, P: Pattern<'a>>(&'a self, pat: P) -> Option<usize> {
1937 fn split_at(&self, mid: usize) -> (&str, &str) {
1938 // is_char_boundary checks that the index is in [0, .len()]
1939 if self.is_char_boundary(mid) {
1941 (self.slice_unchecked(0, mid),
1942 self.slice_unchecked(mid, self.len()))
1945 slice_error_fail(self, 0, mid)
1949 fn split_at_mut(&mut self, mid: usize) -> (&mut str, &mut str) {
1950 // is_char_boundary checks that the index is in [0, .len()]
1951 if self.is_char_boundary(mid) {
1952 let len = self.len();
1953 let ptr = self.as_ptr() as *mut u8;
1955 (from_raw_parts_mut(ptr, mid),
1956 from_raw_parts_mut(ptr.offset(mid as isize), len - mid))
1959 slice_error_fail(self, 0, mid)
1964 fn as_ptr(&self) -> *const u8 {
1965 self as *const str as *const u8
1969 fn len(&self) -> usize {
1970 self.as_bytes().len()
1974 fn is_empty(&self) -> bool { self.len() == 0 }
1977 fn parse<T: FromStr>(&self) -> Result<T, T::Err> { FromStr::from_str(self) }
1980 #[stable(feature = "rust1", since = "1.0.0")]
1981 impl AsRef<[u8]> for str {
1983 fn as_ref(&self) -> &[u8] {
1988 #[stable(feature = "rust1", since = "1.0.0")]
1989 impl<'a> Default for &'a str {
1990 /// Creates an empty str
1991 fn default() -> &'a str { "" }