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87e494c4cd
Implement split_inclusive for slice and str
# Overview
* Implement `split_inclusive` for `slice` and `str` and `split_inclusive_mut` for `slice`
* `split_inclusive` is a substring/subslice splitting iterator that includes the matched part in the iterated substrings as a terminator.
* EDIT: The behaviour has now changed, as per @KodrAus 's input, to the same semantics with the `split_terminator` function. I updated the examples below.
* Two examples below:
```Rust
let data = "\nMäry häd ä little lämb\nLittle lämb\n";
let split: Vec<&str> = data.split_inclusive('\n').collect();
assert_eq!(split, ["\n", "Märy häd ä little lämb\n", "Little lämb\n"]);
```
```Rust
let uppercase_separated = "SheePSharKTurtlECaT";
let mut first_char = true;
let split: Vec<&str> = uppercase_separated.split_inclusive(|c: char| {
let split = !first_char && c.is_uppercase();
first_char = split;
split
}).collect();
assert_eq!(split, ["SheeP", "SharK", "TurtlE", "CaT"]);
```
# Justification for the API
* I was surprised to find that stdlib currently only has splitting iterators that leave out the matched part. In my experience, wanting to leave a substring terminator as a part of the substring is a pretty common usecase.
* This API is strictly more expressive than the standard `split` API: it's easy to get the behaviour of `split` by mapping a subslicing operation that drops the terminator. On the other hand it's impossible to derive this behaviour from `split` without using hacky and brittle `unsafe` code. The normal way to achieve this functionality would be implementing the iterator yourself.
* Especially when dealing with mutable slices, the only way currently is to use `split_at_mut`. This API provides an ergonomic alternative that plays to the strengths of the iterating capabilities of Rust. (Using `split_at_mut` iteratively used to be a real pain before NLL, fortunately the situation is a bit better now.)
# Discussion items
* <s>Does it make sense to mimic `split_terminator` in that the final empty slice would be left off in case of the string/slice ending with a terminator? It might do, as this use case is naturally geared towards considering the matching part as a terminator instead of a separator.</s>
* EDIT: The behaviour was changed to mimic `split_terminator`.
* Does it make sense to have `split_inclusive_mut` for `&mut str`?
4777 lines
150 KiB
Rust
4777 lines
150 KiB
Rust
// ignore-tidy-filelength
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||
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//! String manipulation.
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//!
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//! For more details, see the `std::str` module.
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#![stable(feature = "rust1", since = "1.0.0")]
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use self::pattern::Pattern;
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use self::pattern::{DoubleEndedSearcher, ReverseSearcher, SearchStep, Searcher};
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use crate::char;
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use crate::fmt::{self, Write};
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use crate::iter::{Chain, FlatMap, Flatten};
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use crate::iter::{Copied, Filter, FusedIterator, Map, TrustedLen, TrustedRandomAccess};
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use crate::mem;
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use crate::ops::Try;
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use crate::option;
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use crate::slice::{self, SliceIndex, Split as SliceSplit};
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pub mod pattern;
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#[unstable(feature = "str_internals", issue = "none")]
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#[allow(missing_docs)]
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pub mod lossy;
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/// Parse a value from a string
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///
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/// `FromStr`'s [`from_str`] method is often used implicitly, through
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/// [`str`]'s [`parse`] method. See [`parse`]'s documentation for examples.
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///
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/// [`from_str`]: #tymethod.from_str
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/// [`str`]: ../../std/primitive.str.html
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/// [`parse`]: ../../std/primitive.str.html#method.parse
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///
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/// `FromStr` does not have a lifetime parameter, and so you can only parse types
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/// that do not contain a lifetime parameter themselves. In other words, you can
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/// parse an `i32` with `FromStr`, but not a `&i32`. You can parse a struct that
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/// contains an `i32`, but not one that contains an `&i32`.
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///
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/// # Examples
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///
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/// Basic implementation of `FromStr` on an example `Point` type:
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///
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/// ```
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/// use std::str::FromStr;
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/// use std::num::ParseIntError;
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///
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/// #[derive(Debug, PartialEq)]
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/// struct Point {
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/// x: i32,
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/// y: i32
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/// }
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///
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/// impl FromStr for Point {
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/// type Err = ParseIntError;
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///
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/// fn from_str(s: &str) -> Result<Self, Self::Err> {
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/// let coords: Vec<&str> = s.trim_matches(|p| p == '(' || p == ')' )
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/// .split(',')
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/// .collect();
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///
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/// let x_fromstr = coords[0].parse::<i32>()?;
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/// let y_fromstr = coords[1].parse::<i32>()?;
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///
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/// Ok(Point { x: x_fromstr, y: y_fromstr })
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/// }
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/// }
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///
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/// let p = Point::from_str("(1,2)");
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/// assert_eq!(p.unwrap(), Point{ x: 1, y: 2} )
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub trait FromStr: Sized {
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/// The associated error which can be returned from parsing.
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#[stable(feature = "rust1", since = "1.0.0")]
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type Err;
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/// Parses a string `s` to return a value of this type.
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///
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/// If parsing succeeds, return the value inside [`Ok`], otherwise
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/// when the string is ill-formatted return an error specific to the
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/// inside [`Err`]. The error type is specific to implementation of the trait.
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///
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/// [`Ok`]: ../../std/result/enum.Result.html#variant.Ok
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/// [`Err`]: ../../std/result/enum.Result.html#variant.Err
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///
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/// # Examples
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///
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/// Basic usage with [`i32`][ithirtytwo], a type that implements `FromStr`:
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///
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/// [ithirtytwo]: ../../std/primitive.i32.html
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///
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/// ```
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/// use std::str::FromStr;
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///
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/// let s = "5";
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/// let x = i32::from_str(s).unwrap();
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///
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/// assert_eq!(5, x);
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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fn from_str(s: &str) -> Result<Self, Self::Err>;
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}
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#[stable(feature = "rust1", since = "1.0.0")]
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impl FromStr for bool {
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type Err = ParseBoolError;
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/// Parse a `bool` from a string.
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///
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/// Yields a `Result<bool, ParseBoolError>`, because `s` may or may not
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/// actually be parseable.
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///
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/// # Examples
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///
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/// ```
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/// use std::str::FromStr;
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///
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/// assert_eq!(FromStr::from_str("true"), Ok(true));
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/// assert_eq!(FromStr::from_str("false"), Ok(false));
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/// assert!(<bool as FromStr>::from_str("not even a boolean").is_err());
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/// ```
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///
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/// Note, in many cases, the `.parse()` method on `str` is more proper.
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///
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/// ```
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/// assert_eq!("true".parse(), Ok(true));
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/// assert_eq!("false".parse(), Ok(false));
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/// assert!("not even a boolean".parse::<bool>().is_err());
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/// ```
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#[inline]
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fn from_str(s: &str) -> Result<bool, ParseBoolError> {
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match s {
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"true" => Ok(true),
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"false" => Ok(false),
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_ => Err(ParseBoolError { _priv: () }),
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}
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}
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}
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/// An error returned when parsing a `bool` using [`from_str`] fails
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///
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/// [`from_str`]: ../../std/primitive.bool.html#method.from_str
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#[derive(Debug, Clone, PartialEq, Eq)]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub struct ParseBoolError {
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_priv: (),
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}
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#[stable(feature = "rust1", since = "1.0.0")]
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impl fmt::Display for ParseBoolError {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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"provided string was not `true` or `false`".fmt(f)
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}
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}
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/*
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Section: Creating a string
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*/
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/// Errors which can occur when attempting to interpret a sequence of [`u8`]
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/// as a string.
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///
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/// [`u8`]: ../../std/primitive.u8.html
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///
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/// As such, the `from_utf8` family of functions and methods for both [`String`]s
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/// and [`&str`]s make use of this error, for example.
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///
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/// [`String`]: ../../std/string/struct.String.html#method.from_utf8
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/// [`&str`]: ../../std/str/fn.from_utf8.html
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///
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/// # Examples
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///
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/// This error type’s methods can be used to create functionality
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/// similar to `String::from_utf8_lossy` without allocating heap memory:
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///
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/// ```
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/// fn from_utf8_lossy<F>(mut input: &[u8], mut push: F) where F: FnMut(&str) {
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/// loop {
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/// match std::str::from_utf8(input) {
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/// Ok(valid) => {
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/// push(valid);
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/// break
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/// }
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/// Err(error) => {
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/// let (valid, after_valid) = input.split_at(error.valid_up_to());
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/// unsafe {
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/// push(std::str::from_utf8_unchecked(valid))
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/// }
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/// push("\u{FFFD}");
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///
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/// if let Some(invalid_sequence_length) = error.error_len() {
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/// input = &after_valid[invalid_sequence_length..]
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/// } else {
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/// break
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||
/// }
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||
/// }
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/// }
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/// }
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/// }
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/// ```
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#[derive(Copy, Eq, PartialEq, Clone, Debug)]
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#[stable(feature = "rust1", since = "1.0.0")]
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pub struct Utf8Error {
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valid_up_to: usize,
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error_len: Option<u8>,
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}
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impl Utf8Error {
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/// Returns the index in the given string up to which valid UTF-8 was
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/// verified.
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///
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/// It is the maximum index such that `from_utf8(&input[..index])`
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/// would return `Ok(_)`.
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///
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/// # Examples
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///
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/// Basic usage:
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///
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/// ```
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/// use std::str;
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///
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/// // some invalid bytes, in a vector
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/// let sparkle_heart = vec![0, 159, 146, 150];
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///
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/// // std::str::from_utf8 returns a Utf8Error
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/// let error = str::from_utf8(&sparkle_heart).unwrap_err();
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///
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/// // the second byte is invalid here
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/// assert_eq!(1, error.valid_up_to());
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/// ```
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#[stable(feature = "utf8_error", since = "1.5.0")]
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pub fn valid_up_to(&self) -> usize {
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self.valid_up_to
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}
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/// Provides more information about the failure:
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///
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/// * `None`: the end of the input was reached unexpectedly.
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/// `self.valid_up_to()` is 1 to 3 bytes from the end of the input.
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/// If a byte stream (such as a file or a network socket) is being decoded incrementally,
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/// this could be a valid `char` whose UTF-8 byte sequence is spanning multiple chunks.
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///
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/// * `Some(len)`: an unexpected byte was encountered.
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/// The length provided is that of the invalid byte sequence
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/// that starts at the index given by `valid_up_to()`.
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/// Decoding should resume after that sequence
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/// (after inserting a [`U+FFFD REPLACEMENT CHARACTER`][U+FFFD]) in case of
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/// lossy decoding.
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///
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/// [U+FFFD]: ../../std/char/constant.REPLACEMENT_CHARACTER.html
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#[stable(feature = "utf8_error_error_len", since = "1.20.0")]
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pub fn error_len(&self) -> Option<usize> {
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self.error_len.map(|len| len as usize)
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}
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}
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/// Converts a slice of bytes to a string slice.
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///
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/// A string slice ([`&str`]) is made of bytes ([`u8`]), and a byte slice
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/// ([`&[u8]`][byteslice]) is made of bytes, so this function converts between
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/// the two. Not all byte slices are valid string slices, however: [`&str`] requires
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/// that it is valid UTF-8. `from_utf8()` checks to ensure that the bytes are valid
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/// UTF-8, and then does the conversion.
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///
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/// [`&str`]: ../../std/primitive.str.html
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/// [`u8`]: ../../std/primitive.u8.html
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/// [byteslice]: ../../std/primitive.slice.html
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///
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/// If you are sure that the byte slice is valid UTF-8, and you don't want to
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/// incur the overhead of the validity check, there is an unsafe version of
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/// this function, [`from_utf8_unchecked`][fromutf8u], which has the same
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/// behavior but skips the check.
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///
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/// [fromutf8u]: fn.from_utf8_unchecked.html
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///
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/// If you need a `String` instead of a `&str`, consider
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/// [`String::from_utf8`][string].
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///
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/// [string]: ../../std/string/struct.String.html#method.from_utf8
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///
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/// Because you can stack-allocate a `[u8; N]`, and you can take a
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/// [`&[u8]`][byteslice] of it, this function is one way to have a
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/// stack-allocated string. There is an example of this in the
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/// examples section below.
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///
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/// [byteslice]: ../../std/primitive.slice.html
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///
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/// # Errors
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///
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/// Returns `Err` if the slice is not UTF-8 with a description as to why the
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/// provided slice is not UTF-8.
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///
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/// # Examples
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///
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/// Basic usage:
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///
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/// ```
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/// use std::str;
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///
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/// // some bytes, in a vector
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/// let sparkle_heart = vec![240, 159, 146, 150];
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///
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/// // We know these bytes are valid, so just use `unwrap()`.
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/// let sparkle_heart = str::from_utf8(&sparkle_heart).unwrap();
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///
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/// assert_eq!("💖", sparkle_heart);
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/// ```
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///
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/// Incorrect bytes:
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///
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/// ```
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/// use std::str;
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///
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/// // some invalid bytes, in a vector
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/// let sparkle_heart = vec![0, 159, 146, 150];
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///
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/// assert!(str::from_utf8(&sparkle_heart).is_err());
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/// ```
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///
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/// See the docs for [`Utf8Error`][error] for more details on the kinds of
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/// errors that can be returned.
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///
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/// [error]: struct.Utf8Error.html
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///
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/// A "stack allocated string":
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///
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/// ```
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/// use std::str;
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///
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/// // some bytes, in a stack-allocated array
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/// let sparkle_heart = [240, 159, 146, 150];
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///
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/// // We know these bytes are valid, so just use `unwrap()`.
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/// let sparkle_heart = str::from_utf8(&sparkle_heart).unwrap();
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///
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/// assert_eq!("💖", sparkle_heart);
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/// ```
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#[stable(feature = "rust1", since = "1.0.0")]
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pub fn from_utf8(v: &[u8]) -> Result<&str, Utf8Error> {
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run_utf8_validation(v)?;
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// SAFETY: Just ran validation.
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Ok(unsafe { from_utf8_unchecked(v) })
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}
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|
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/// Converts a mutable slice of bytes to a mutable string slice.
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///
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/// # Examples
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||
///
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/// Basic usage:
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///
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/// ```
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/// use std::str;
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///
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/// // "Hello, Rust!" as a mutable vector
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/// let mut hellorust = vec![72, 101, 108, 108, 111, 44, 32, 82, 117, 115, 116, 33];
|
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///
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/// // As we know these bytes are valid, we can use `unwrap()`
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/// let outstr = str::from_utf8_mut(&mut hellorust).unwrap();
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///
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/// assert_eq!("Hello, Rust!", outstr);
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/// ```
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///
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/// Incorrect bytes:
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///
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/// ```
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/// use std::str;
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///
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/// // Some invalid bytes in a mutable vector
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/// let mut invalid = vec![128, 223];
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///
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/// assert!(str::from_utf8_mut(&mut invalid).is_err());
|
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/// ```
|
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/// See the docs for [`Utf8Error`][error] for more details on the kinds of
|
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/// errors that can be returned.
|
||
///
|
||
/// [error]: struct.Utf8Error.html
|
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#[stable(feature = "str_mut_extras", since = "1.20.0")]
|
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pub fn from_utf8_mut(v: &mut [u8]) -> Result<&mut str, Utf8Error> {
|
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run_utf8_validation(v)?;
|
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// SAFETY: Just ran validation.
|
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Ok(unsafe { from_utf8_unchecked_mut(v) })
|
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}
|
||
|
||
/// Converts a slice of bytes to a string slice without checking
|
||
/// that the string contains valid UTF-8.
|
||
///
|
||
/// See the safe version, [`from_utf8`][fromutf8], for more information.
|
||
///
|
||
/// [fromutf8]: fn.from_utf8.html
|
||
///
|
||
/// # Safety
|
||
///
|
||
/// This function is unsafe because it does not check that the bytes passed to
|
||
/// it are valid UTF-8. If this constraint is violated, undefined behavior
|
||
/// results, as the rest of Rust assumes that [`&str`]s are valid UTF-8.
|
||
///
|
||
/// [`&str`]: ../../std/primitive.str.html
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// use std::str;
|
||
///
|
||
/// // some bytes, in a vector
|
||
/// let sparkle_heart = vec![240, 159, 146, 150];
|
||
///
|
||
/// let sparkle_heart = unsafe {
|
||
/// str::from_utf8_unchecked(&sparkle_heart)
|
||
/// };
|
||
///
|
||
/// assert_eq!("💖", sparkle_heart);
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||
/// ```
|
||
#[inline]
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub unsafe fn from_utf8_unchecked(v: &[u8]) -> &str {
|
||
&*(v as *const [u8] as *const str)
|
||
}
|
||
|
||
/// Converts a slice of bytes to a string slice without checking
|
||
/// that the string contains valid UTF-8; mutable version.
|
||
///
|
||
/// See the immutable version, [`from_utf8_unchecked()`][fromutf8], for more information.
|
||
///
|
||
/// [fromutf8]: fn.from_utf8_unchecked.html
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// use std::str;
|
||
///
|
||
/// let mut heart = vec![240, 159, 146, 150];
|
||
/// let heart = unsafe { str::from_utf8_unchecked_mut(&mut heart) };
|
||
///
|
||
/// assert_eq!("💖", heart);
|
||
/// ```
|
||
#[inline]
|
||
#[stable(feature = "str_mut_extras", since = "1.20.0")]
|
||
pub unsafe fn from_utf8_unchecked_mut(v: &mut [u8]) -> &mut str {
|
||
&mut *(v as *mut [u8] as *mut str)
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl fmt::Display for Utf8Error {
|
||
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
||
if let Some(error_len) = self.error_len {
|
||
write!(
|
||
f,
|
||
"invalid utf-8 sequence of {} bytes from index {}",
|
||
error_len, self.valid_up_to
|
||
)
|
||
} else {
|
||
write!(f, "incomplete utf-8 byte sequence from index {}", self.valid_up_to)
|
||
}
|
||
}
|
||
}
|
||
|
||
/*
|
||
Section: Iterators
|
||
*/
|
||
|
||
/// An iterator over the [`char`]s of a string slice.
|
||
///
|
||
/// [`char`]: ../../std/primitive.char.html
|
||
///
|
||
/// This struct is created by the [`chars`] method on [`str`].
|
||
/// See its documentation for more.
|
||
///
|
||
/// [`chars`]: ../../std/primitive.str.html#method.chars
|
||
/// [`str`]: ../../std/primitive.str.html
|
||
#[derive(Clone)]
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub struct Chars<'a> {
|
||
iter: slice::Iter<'a, u8>,
|
||
}
|
||
|
||
/// Returns the initial codepoint accumulator for the first byte.
|
||
/// The first byte is special, only want bottom 5 bits for width 2, 4 bits
|
||
/// for width 3, and 3 bits for width 4.
|
||
#[inline]
|
||
fn utf8_first_byte(byte: u8, width: u32) -> u32 {
|
||
(byte & (0x7F >> width)) as u32
|
||
}
|
||
|
||
/// Returns the value of `ch` updated with continuation byte `byte`.
|
||
#[inline]
|
||
fn utf8_acc_cont_byte(ch: u32, byte: u8) -> u32 {
|
||
(ch << 6) | (byte & CONT_MASK) as u32
|
||
}
|
||
|
||
/// Checks whether the byte is a UTF-8 continuation byte (i.e., starts with the
|
||
/// bits `10`).
|
||
#[inline]
|
||
fn utf8_is_cont_byte(byte: u8) -> bool {
|
||
(byte & !CONT_MASK) == TAG_CONT_U8
|
||
}
|
||
|
||
#[inline]
|
||
fn unwrap_or_0(opt: Option<&u8>) -> u8 {
|
||
match opt {
|
||
Some(&byte) => byte,
|
||
None => 0,
|
||
}
|
||
}
|
||
|
||
/// Reads the next code point out of a byte iterator (assuming a
|
||
/// UTF-8-like encoding).
|
||
#[unstable(feature = "str_internals", issue = "none")]
|
||
#[inline]
|
||
pub fn next_code_point<'a, I: Iterator<Item = &'a u8>>(bytes: &mut I) -> Option<u32> {
|
||
// Decode UTF-8
|
||
let x = *bytes.next()?;
|
||
if x < 128 {
|
||
return Some(x as u32);
|
||
}
|
||
|
||
// Multibyte case follows
|
||
// Decode from a byte combination out of: [[[x y] z] w]
|
||
// NOTE: Performance is sensitive to the exact formulation here
|
||
let init = utf8_first_byte(x, 2);
|
||
let y = unwrap_or_0(bytes.next());
|
||
let mut ch = utf8_acc_cont_byte(init, y);
|
||
if x >= 0xE0 {
|
||
// [[x y z] w] case
|
||
// 5th bit in 0xE0 .. 0xEF is always clear, so `init` is still valid
|
||
let z = unwrap_or_0(bytes.next());
|
||
let y_z = utf8_acc_cont_byte((y & CONT_MASK) as u32, z);
|
||
ch = init << 12 | y_z;
|
||
if x >= 0xF0 {
|
||
// [x y z w] case
|
||
// use only the lower 3 bits of `init`
|
||
let w = unwrap_or_0(bytes.next());
|
||
ch = (init & 7) << 18 | utf8_acc_cont_byte(y_z, w);
|
||
}
|
||
}
|
||
|
||
Some(ch)
|
||
}
|
||
|
||
/// Reads the last code point out of a byte iterator (assuming a
|
||
/// UTF-8-like encoding).
|
||
#[inline]
|
||
fn next_code_point_reverse<'a, I>(bytes: &mut I) -> Option<u32>
|
||
where
|
||
I: DoubleEndedIterator<Item = &'a u8>,
|
||
{
|
||
// Decode UTF-8
|
||
let w = match *bytes.next_back()? {
|
||
next_byte if next_byte < 128 => return Some(next_byte as u32),
|
||
back_byte => back_byte,
|
||
};
|
||
|
||
// Multibyte case follows
|
||
// Decode from a byte combination out of: [x [y [z w]]]
|
||
let mut ch;
|
||
let z = unwrap_or_0(bytes.next_back());
|
||
ch = utf8_first_byte(z, 2);
|
||
if utf8_is_cont_byte(z) {
|
||
let y = unwrap_or_0(bytes.next_back());
|
||
ch = utf8_first_byte(y, 3);
|
||
if utf8_is_cont_byte(y) {
|
||
let x = unwrap_or_0(bytes.next_back());
|
||
ch = utf8_first_byte(x, 4);
|
||
ch = utf8_acc_cont_byte(ch, y);
|
||
}
|
||
ch = utf8_acc_cont_byte(ch, z);
|
||
}
|
||
ch = utf8_acc_cont_byte(ch, w);
|
||
|
||
Some(ch)
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<'a> Iterator for Chars<'a> {
|
||
type Item = char;
|
||
|
||
#[inline]
|
||
fn next(&mut self) -> Option<char> {
|
||
next_code_point(&mut self.iter).map(|ch| {
|
||
// SAFETY: `str` invariant says `ch` is a valid Unicode Scalar Value.
|
||
unsafe { char::from_u32_unchecked(ch) }
|
||
})
|
||
}
|
||
|
||
#[inline]
|
||
fn count(self) -> usize {
|
||
// length in `char` is equal to the number of non-continuation bytes
|
||
let bytes_len = self.iter.len();
|
||
let mut cont_bytes = 0;
|
||
for &byte in self.iter {
|
||
cont_bytes += utf8_is_cont_byte(byte) as usize;
|
||
}
|
||
bytes_len - cont_bytes
|
||
}
|
||
|
||
#[inline]
|
||
fn size_hint(&self) -> (usize, Option<usize>) {
|
||
let len = self.iter.len();
|
||
// `(len + 3)` can't overflow, because we know that the `slice::Iter`
|
||
// belongs to a slice in memory which has a maximum length of
|
||
// `isize::MAX` (that's well below `usize::MAX`).
|
||
((len + 3) / 4, Some(len))
|
||
}
|
||
|
||
#[inline]
|
||
fn last(mut self) -> Option<char> {
|
||
// No need to go through the entire string.
|
||
self.next_back()
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "chars_debug_impl", since = "1.38.0")]
|
||
impl fmt::Debug for Chars<'_> {
|
||
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
||
write!(f, "Chars(")?;
|
||
f.debug_list().entries(self.clone()).finish()?;
|
||
write!(f, ")")?;
|
||
Ok(())
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<'a> DoubleEndedIterator for Chars<'a> {
|
||
#[inline]
|
||
fn next_back(&mut self) -> Option<char> {
|
||
next_code_point_reverse(&mut self.iter).map(|ch| {
|
||
// SAFETY: `str` invariant says `ch` is a valid Unicode Scalar Value.
|
||
unsafe { char::from_u32_unchecked(ch) }
|
||
})
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "fused", since = "1.26.0")]
|
||
impl FusedIterator for Chars<'_> {}
|
||
|
||
impl<'a> Chars<'a> {
|
||
/// Views the underlying data as a subslice of the original data.
|
||
///
|
||
/// This has the same lifetime as the original slice, and so the
|
||
/// iterator can continue to be used while this exists.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// let mut chars = "abc".chars();
|
||
///
|
||
/// assert_eq!(chars.as_str(), "abc");
|
||
/// chars.next();
|
||
/// assert_eq!(chars.as_str(), "bc");
|
||
/// chars.next();
|
||
/// chars.next();
|
||
/// assert_eq!(chars.as_str(), "");
|
||
/// ```
|
||
#[stable(feature = "iter_to_slice", since = "1.4.0")]
|
||
#[inline]
|
||
pub fn as_str(&self) -> &'a str {
|
||
// SAFETY: `Chars` is only made from a str, which guarantees the iter is valid UTF-8.
|
||
unsafe { from_utf8_unchecked(self.iter.as_slice()) }
|
||
}
|
||
}
|
||
|
||
/// An iterator over the [`char`]s of a string slice, and their positions.
|
||
///
|
||
/// [`char`]: ../../std/primitive.char.html
|
||
///
|
||
/// This struct is created by the [`char_indices`] method on [`str`].
|
||
/// See its documentation for more.
|
||
///
|
||
/// [`char_indices`]: ../../std/primitive.str.html#method.char_indices
|
||
/// [`str`]: ../../std/primitive.str.html
|
||
#[derive(Clone, Debug)]
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub struct CharIndices<'a> {
|
||
front_offset: usize,
|
||
iter: Chars<'a>,
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<'a> Iterator for CharIndices<'a> {
|
||
type Item = (usize, char);
|
||
|
||
#[inline]
|
||
fn next(&mut self) -> Option<(usize, char)> {
|
||
let pre_len = self.iter.iter.len();
|
||
match self.iter.next() {
|
||
None => None,
|
||
Some(ch) => {
|
||
let index = self.front_offset;
|
||
let len = self.iter.iter.len();
|
||
self.front_offset += pre_len - len;
|
||
Some((index, ch))
|
||
}
|
||
}
|
||
}
|
||
|
||
#[inline]
|
||
fn count(self) -> usize {
|
||
self.iter.count()
|
||
}
|
||
|
||
#[inline]
|
||
fn size_hint(&self) -> (usize, Option<usize>) {
|
||
self.iter.size_hint()
|
||
}
|
||
|
||
#[inline]
|
||
fn last(mut self) -> Option<(usize, char)> {
|
||
// No need to go through the entire string.
|
||
self.next_back()
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<'a> DoubleEndedIterator for CharIndices<'a> {
|
||
#[inline]
|
||
fn next_back(&mut self) -> Option<(usize, char)> {
|
||
self.iter.next_back().map(|ch| {
|
||
let index = self.front_offset + self.iter.iter.len();
|
||
(index, ch)
|
||
})
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "fused", since = "1.26.0")]
|
||
impl FusedIterator for CharIndices<'_> {}
|
||
|
||
impl<'a> CharIndices<'a> {
|
||
/// Views the underlying data as a subslice of the original data.
|
||
///
|
||
/// This has the same lifetime as the original slice, and so the
|
||
/// iterator can continue to be used while this exists.
|
||
#[stable(feature = "iter_to_slice", since = "1.4.0")]
|
||
#[inline]
|
||
pub fn as_str(&self) -> &'a str {
|
||
self.iter.as_str()
|
||
}
|
||
}
|
||
|
||
/// An iterator over the bytes of a string slice.
|
||
///
|
||
/// This struct is created by the [`bytes`] method on [`str`].
|
||
/// See its documentation for more.
|
||
///
|
||
/// [`bytes`]: ../../std/primitive.str.html#method.bytes
|
||
/// [`str`]: ../../std/primitive.str.html
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[derive(Clone, Debug)]
|
||
pub struct Bytes<'a>(Copied<slice::Iter<'a, u8>>);
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl Iterator for Bytes<'_> {
|
||
type Item = u8;
|
||
|
||
#[inline]
|
||
fn next(&mut self) -> Option<u8> {
|
||
self.0.next()
|
||
}
|
||
|
||
#[inline]
|
||
fn size_hint(&self) -> (usize, Option<usize>) {
|
||
self.0.size_hint()
|
||
}
|
||
|
||
#[inline]
|
||
fn count(self) -> usize {
|
||
self.0.count()
|
||
}
|
||
|
||
#[inline]
|
||
fn last(self) -> Option<Self::Item> {
|
||
self.0.last()
|
||
}
|
||
|
||
#[inline]
|
||
fn nth(&mut self, n: usize) -> Option<Self::Item> {
|
||
self.0.nth(n)
|
||
}
|
||
|
||
#[inline]
|
||
fn all<F>(&mut self, f: F) -> bool
|
||
where
|
||
F: FnMut(Self::Item) -> bool,
|
||
{
|
||
self.0.all(f)
|
||
}
|
||
|
||
#[inline]
|
||
fn any<F>(&mut self, f: F) -> bool
|
||
where
|
||
F: FnMut(Self::Item) -> bool,
|
||
{
|
||
self.0.any(f)
|
||
}
|
||
|
||
#[inline]
|
||
fn find<P>(&mut self, predicate: P) -> Option<Self::Item>
|
||
where
|
||
P: FnMut(&Self::Item) -> bool,
|
||
{
|
||
self.0.find(predicate)
|
||
}
|
||
|
||
#[inline]
|
||
fn position<P>(&mut self, predicate: P) -> Option<usize>
|
||
where
|
||
P: FnMut(Self::Item) -> bool,
|
||
{
|
||
self.0.position(predicate)
|
||
}
|
||
|
||
#[inline]
|
||
fn rposition<P>(&mut self, predicate: P) -> Option<usize>
|
||
where
|
||
P: FnMut(Self::Item) -> bool,
|
||
{
|
||
self.0.rposition(predicate)
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl DoubleEndedIterator for Bytes<'_> {
|
||
#[inline]
|
||
fn next_back(&mut self) -> Option<u8> {
|
||
self.0.next_back()
|
||
}
|
||
|
||
#[inline]
|
||
fn nth_back(&mut self, n: usize) -> Option<Self::Item> {
|
||
self.0.nth_back(n)
|
||
}
|
||
|
||
#[inline]
|
||
fn rfind<P>(&mut self, predicate: P) -> Option<Self::Item>
|
||
where
|
||
P: FnMut(&Self::Item) -> bool,
|
||
{
|
||
self.0.rfind(predicate)
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl ExactSizeIterator for Bytes<'_> {
|
||
#[inline]
|
||
fn len(&self) -> usize {
|
||
self.0.len()
|
||
}
|
||
|
||
#[inline]
|
||
fn is_empty(&self) -> bool {
|
||
self.0.is_empty()
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "fused", since = "1.26.0")]
|
||
impl FusedIterator for Bytes<'_> {}
|
||
|
||
#[unstable(feature = "trusted_len", issue = "37572")]
|
||
unsafe impl TrustedLen for Bytes<'_> {}
|
||
|
||
#[doc(hidden)]
|
||
unsafe impl TrustedRandomAccess for Bytes<'_> {
|
||
unsafe fn get_unchecked(&mut self, i: usize) -> u8 {
|
||
self.0.get_unchecked(i)
|
||
}
|
||
fn may_have_side_effect() -> bool {
|
||
false
|
||
}
|
||
}
|
||
|
||
/// This macro generates a Clone impl for string pattern API
|
||
/// wrapper types of the form X<'a, P>
|
||
macro_rules! derive_pattern_clone {
|
||
(clone $t:ident with |$s:ident| $e:expr) => {
|
||
impl<'a, P> Clone for $t<'a, P>
|
||
where
|
||
P: Pattern<'a, Searcher: Clone>,
|
||
{
|
||
fn clone(&self) -> Self {
|
||
let $s = self;
|
||
$e
|
||
}
|
||
}
|
||
};
|
||
}
|
||
|
||
/// This macro generates two public iterator structs
|
||
/// wrapping a private internal one that makes use of the `Pattern` API.
|
||
///
|
||
/// For all patterns `P: Pattern<'a>` the following items will be
|
||
/// generated (generics omitted):
|
||
///
|
||
/// struct $forward_iterator($internal_iterator);
|
||
/// struct $reverse_iterator($internal_iterator);
|
||
///
|
||
/// impl Iterator for $forward_iterator
|
||
/// { /* internal ends up calling Searcher::next_match() */ }
|
||
///
|
||
/// impl DoubleEndedIterator for $forward_iterator
|
||
/// where P::Searcher: DoubleEndedSearcher
|
||
/// { /* internal ends up calling Searcher::next_match_back() */ }
|
||
///
|
||
/// impl Iterator for $reverse_iterator
|
||
/// where P::Searcher: ReverseSearcher
|
||
/// { /* internal ends up calling Searcher::next_match_back() */ }
|
||
///
|
||
/// impl DoubleEndedIterator for $reverse_iterator
|
||
/// where P::Searcher: DoubleEndedSearcher
|
||
/// { /* internal ends up calling Searcher::next_match() */ }
|
||
///
|
||
/// The internal one is defined outside the macro, and has almost the same
|
||
/// semantic as a DoubleEndedIterator by delegating to `pattern::Searcher` and
|
||
/// `pattern::ReverseSearcher` for both forward and reverse iteration.
|
||
///
|
||
/// "Almost", because a `Searcher` and a `ReverseSearcher` for a given
|
||
/// `Pattern` might not return the same elements, so actually implementing
|
||
/// `DoubleEndedIterator` for it would be incorrect.
|
||
/// (See the docs in `str::pattern` for more details)
|
||
///
|
||
/// However, the internal struct still represents a single ended iterator from
|
||
/// either end, and depending on pattern is also a valid double ended iterator,
|
||
/// so the two wrapper structs implement `Iterator`
|
||
/// and `DoubleEndedIterator` depending on the concrete pattern type, leading
|
||
/// to the complex impls seen above.
|
||
macro_rules! generate_pattern_iterators {
|
||
{
|
||
// Forward iterator
|
||
forward:
|
||
$(#[$forward_iterator_attribute:meta])*
|
||
struct $forward_iterator:ident;
|
||
|
||
// Reverse iterator
|
||
reverse:
|
||
$(#[$reverse_iterator_attribute:meta])*
|
||
struct $reverse_iterator:ident;
|
||
|
||
// Stability of all generated items
|
||
stability:
|
||
$(#[$common_stability_attribute:meta])*
|
||
|
||
// Internal almost-iterator that is being delegated to
|
||
internal:
|
||
$internal_iterator:ident yielding ($iterty:ty);
|
||
|
||
// Kind of delegation - either single ended or double ended
|
||
delegate $($t:tt)*
|
||
} => {
|
||
$(#[$forward_iterator_attribute])*
|
||
$(#[$common_stability_attribute])*
|
||
pub struct $forward_iterator<'a, P: Pattern<'a>>($internal_iterator<'a, P>);
|
||
|
||
$(#[$common_stability_attribute])*
|
||
impl<'a, P> fmt::Debug for $forward_iterator<'a, P>
|
||
where
|
||
P: Pattern<'a, Searcher: fmt::Debug>,
|
||
{
|
||
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
||
f.debug_tuple(stringify!($forward_iterator))
|
||
.field(&self.0)
|
||
.finish()
|
||
}
|
||
}
|
||
|
||
$(#[$common_stability_attribute])*
|
||
impl<'a, P: Pattern<'a>> Iterator for $forward_iterator<'a, P> {
|
||
type Item = $iterty;
|
||
|
||
#[inline]
|
||
fn next(&mut self) -> Option<$iterty> {
|
||
self.0.next()
|
||
}
|
||
}
|
||
|
||
$(#[$common_stability_attribute])*
|
||
impl<'a, P> Clone for $forward_iterator<'a, P>
|
||
where
|
||
P: Pattern<'a, Searcher: Clone>,
|
||
{
|
||
fn clone(&self) -> Self {
|
||
$forward_iterator(self.0.clone())
|
||
}
|
||
}
|
||
|
||
$(#[$reverse_iterator_attribute])*
|
||
$(#[$common_stability_attribute])*
|
||
pub struct $reverse_iterator<'a, P: Pattern<'a>>($internal_iterator<'a, P>);
|
||
|
||
$(#[$common_stability_attribute])*
|
||
impl<'a, P> fmt::Debug for $reverse_iterator<'a, P>
|
||
where
|
||
P: Pattern<'a, Searcher: fmt::Debug>,
|
||
{
|
||
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
||
f.debug_tuple(stringify!($reverse_iterator))
|
||
.field(&self.0)
|
||
.finish()
|
||
}
|
||
}
|
||
|
||
$(#[$common_stability_attribute])*
|
||
impl<'a, P> Iterator for $reverse_iterator<'a, P>
|
||
where
|
||
P: Pattern<'a, Searcher: ReverseSearcher<'a>>,
|
||
{
|
||
type Item = $iterty;
|
||
|
||
#[inline]
|
||
fn next(&mut self) -> Option<$iterty> {
|
||
self.0.next_back()
|
||
}
|
||
}
|
||
|
||
$(#[$common_stability_attribute])*
|
||
impl<'a, P> Clone for $reverse_iterator<'a, P>
|
||
where
|
||
P: Pattern<'a, Searcher: Clone>,
|
||
{
|
||
fn clone(&self) -> Self {
|
||
$reverse_iterator(self.0.clone())
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "fused", since = "1.26.0")]
|
||
impl<'a, P: Pattern<'a>> FusedIterator for $forward_iterator<'a, P> {}
|
||
|
||
#[stable(feature = "fused", since = "1.26.0")]
|
||
impl<'a, P> FusedIterator for $reverse_iterator<'a, P>
|
||
where
|
||
P: Pattern<'a, Searcher: ReverseSearcher<'a>>,
|
||
{}
|
||
|
||
generate_pattern_iterators!($($t)* with $(#[$common_stability_attribute])*,
|
||
$forward_iterator,
|
||
$reverse_iterator, $iterty);
|
||
};
|
||
{
|
||
double ended; with $(#[$common_stability_attribute:meta])*,
|
||
$forward_iterator:ident,
|
||
$reverse_iterator:ident, $iterty:ty
|
||
} => {
|
||
$(#[$common_stability_attribute])*
|
||
impl<'a, P> DoubleEndedIterator for $forward_iterator<'a, P>
|
||
where
|
||
P: Pattern<'a, Searcher: DoubleEndedSearcher<'a>>,
|
||
{
|
||
#[inline]
|
||
fn next_back(&mut self) -> Option<$iterty> {
|
||
self.0.next_back()
|
||
}
|
||
}
|
||
|
||
$(#[$common_stability_attribute])*
|
||
impl<'a, P> DoubleEndedIterator for $reverse_iterator<'a, P>
|
||
where
|
||
P: Pattern<'a, Searcher: DoubleEndedSearcher<'a>>,
|
||
{
|
||
#[inline]
|
||
fn next_back(&mut self) -> Option<$iterty> {
|
||
self.0.next()
|
||
}
|
||
}
|
||
};
|
||
{
|
||
single ended; with $(#[$common_stability_attribute:meta])*,
|
||
$forward_iterator:ident,
|
||
$reverse_iterator:ident, $iterty:ty
|
||
} => {}
|
||
}
|
||
|
||
derive_pattern_clone! {
|
||
clone SplitInternal
|
||
with |s| SplitInternal { matcher: s.matcher.clone(), ..*s }
|
||
}
|
||
|
||
struct SplitInternal<'a, P: Pattern<'a>> {
|
||
start: usize,
|
||
end: usize,
|
||
matcher: P::Searcher,
|
||
allow_trailing_empty: bool,
|
||
finished: bool,
|
||
}
|
||
|
||
impl<'a, P> fmt::Debug for SplitInternal<'a, P>
|
||
where
|
||
P: Pattern<'a, Searcher: fmt::Debug>,
|
||
{
|
||
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
||
f.debug_struct("SplitInternal")
|
||
.field("start", &self.start)
|
||
.field("end", &self.end)
|
||
.field("matcher", &self.matcher)
|
||
.field("allow_trailing_empty", &self.allow_trailing_empty)
|
||
.field("finished", &self.finished)
|
||
.finish()
|
||
}
|
||
}
|
||
|
||
impl<'a, P: Pattern<'a>> SplitInternal<'a, P> {
|
||
#[inline]
|
||
fn get_end(&mut self) -> Option<&'a str> {
|
||
if !self.finished && (self.allow_trailing_empty || self.end - self.start > 0) {
|
||
self.finished = true;
|
||
// SAFETY: `self.start` and `self.end` always lie on unicode boundaries.
|
||
unsafe {
|
||
let string = self.matcher.haystack().get_unchecked(self.start..self.end);
|
||
Some(string)
|
||
}
|
||
} else {
|
||
None
|
||
}
|
||
}
|
||
|
||
#[inline]
|
||
fn next(&mut self) -> Option<&'a str> {
|
||
if self.finished {
|
||
return None;
|
||
}
|
||
|
||
let haystack = self.matcher.haystack();
|
||
match self.matcher.next_match() {
|
||
// SAFETY: `Searcher` guarantees that `a` and `b` lie on unicode boundaries.
|
||
Some((a, b)) => unsafe {
|
||
let elt = haystack.get_unchecked(self.start..a);
|
||
self.start = b;
|
||
Some(elt)
|
||
},
|
||
None => self.get_end(),
|
||
}
|
||
}
|
||
|
||
#[inline]
|
||
fn next_inclusive(&mut self) -> Option<&'a str> {
|
||
if self.finished {
|
||
return None;
|
||
}
|
||
|
||
let haystack = self.matcher.haystack();
|
||
match self.matcher.next_match() {
|
||
// SAFETY: `Searcher` guarantees that `b` lies on unicode boundary,
|
||
// and self.start is either the start of the original string,
|
||
// or `b` was assigned to it, so it also lies on unicode boundary.
|
||
Some((_, b)) => unsafe {
|
||
let elt = haystack.get_unchecked(self.start..b);
|
||
self.start = b;
|
||
Some(elt)
|
||
},
|
||
None => self.get_end(),
|
||
}
|
||
}
|
||
|
||
#[inline]
|
||
fn next_back(&mut self) -> Option<&'a str>
|
||
where
|
||
P::Searcher: ReverseSearcher<'a>,
|
||
{
|
||
if self.finished {
|
||
return None;
|
||
}
|
||
|
||
if !self.allow_trailing_empty {
|
||
self.allow_trailing_empty = true;
|
||
match self.next_back() {
|
||
Some(elt) if !elt.is_empty() => return Some(elt),
|
||
_ => {
|
||
if self.finished {
|
||
return None;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
let haystack = self.matcher.haystack();
|
||
match self.matcher.next_match_back() {
|
||
// SAFETY: `Searcher` guarantees that `a` and `b` lie on unicode boundaries.
|
||
Some((a, b)) => unsafe {
|
||
let elt = haystack.get_unchecked(b..self.end);
|
||
self.end = a;
|
||
Some(elt)
|
||
},
|
||
// SAFETY: `self.start` and `self.end` always lie on unicode boundaries.
|
||
None => unsafe {
|
||
self.finished = true;
|
||
Some(haystack.get_unchecked(self.start..self.end))
|
||
},
|
||
}
|
||
}
|
||
|
||
#[inline]
|
||
fn next_back_inclusive(&mut self) -> Option<&'a str>
|
||
where
|
||
P::Searcher: ReverseSearcher<'a>,
|
||
{
|
||
if self.finished {
|
||
return None;
|
||
}
|
||
|
||
if !self.allow_trailing_empty {
|
||
self.allow_trailing_empty = true;
|
||
match self.next_back_inclusive() {
|
||
Some(elt) if !elt.is_empty() => return Some(elt),
|
||
_ => {
|
||
if self.finished {
|
||
return None;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
let haystack = self.matcher.haystack();
|
||
match self.matcher.next_match_back() {
|
||
// SAFETY: `Searcher` guarantees that `b` lies on unicode boundary,
|
||
// and self.end is either the end of the original string,
|
||
// or `b` was assigned to it, so it also lies on unicode boundary.
|
||
Some((_, b)) => unsafe {
|
||
let elt = haystack.get_unchecked(b..self.end);
|
||
self.end = b;
|
||
Some(elt)
|
||
},
|
||
// SAFETY: self.start is either the start of the original string,
|
||
// or start of a substring that represents the part of the string that hasn't
|
||
// iterated yet. Either way, it is guaranteed to lie on unicode boundary.
|
||
// self.end is either the end of the original string,
|
||
// or `b` was assigned to it, so it also lies on unicode boundary.
|
||
None => unsafe {
|
||
self.finished = true;
|
||
Some(haystack.get_unchecked(self.start..self.end))
|
||
},
|
||
}
|
||
}
|
||
}
|
||
|
||
generate_pattern_iterators! {
|
||
forward:
|
||
/// Created with the method [`split`].
|
||
///
|
||
/// [`split`]: ../../std/primitive.str.html#method.split
|
||
struct Split;
|
||
reverse:
|
||
/// Created with the method [`rsplit`].
|
||
///
|
||
/// [`rsplit`]: ../../std/primitive.str.html#method.rsplit
|
||
struct RSplit;
|
||
stability:
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
internal:
|
||
SplitInternal yielding (&'a str);
|
||
delegate double ended;
|
||
}
|
||
|
||
generate_pattern_iterators! {
|
||
forward:
|
||
/// Created with the method [`split_terminator`].
|
||
///
|
||
/// [`split_terminator`]: ../../std/primitive.str.html#method.split_terminator
|
||
struct SplitTerminator;
|
||
reverse:
|
||
/// Created with the method [`rsplit_terminator`].
|
||
///
|
||
/// [`rsplit_terminator`]: ../../std/primitive.str.html#method.rsplit_terminator
|
||
struct RSplitTerminator;
|
||
stability:
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
internal:
|
||
SplitInternal yielding (&'a str);
|
||
delegate double ended;
|
||
}
|
||
|
||
derive_pattern_clone! {
|
||
clone SplitNInternal
|
||
with |s| SplitNInternal { iter: s.iter.clone(), ..*s }
|
||
}
|
||
|
||
struct SplitNInternal<'a, P: Pattern<'a>> {
|
||
iter: SplitInternal<'a, P>,
|
||
/// The number of splits remaining
|
||
count: usize,
|
||
}
|
||
|
||
impl<'a, P> fmt::Debug for SplitNInternal<'a, P>
|
||
where
|
||
P: Pattern<'a, Searcher: fmt::Debug>,
|
||
{
|
||
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
||
f.debug_struct("SplitNInternal")
|
||
.field("iter", &self.iter)
|
||
.field("count", &self.count)
|
||
.finish()
|
||
}
|
||
}
|
||
|
||
impl<'a, P: Pattern<'a>> SplitNInternal<'a, P> {
|
||
#[inline]
|
||
fn next(&mut self) -> Option<&'a str> {
|
||
match self.count {
|
||
0 => None,
|
||
1 => {
|
||
self.count = 0;
|
||
self.iter.get_end()
|
||
}
|
||
_ => {
|
||
self.count -= 1;
|
||
self.iter.next()
|
||
}
|
||
}
|
||
}
|
||
|
||
#[inline]
|
||
fn next_back(&mut self) -> Option<&'a str>
|
||
where
|
||
P::Searcher: ReverseSearcher<'a>,
|
||
{
|
||
match self.count {
|
||
0 => None,
|
||
1 => {
|
||
self.count = 0;
|
||
self.iter.get_end()
|
||
}
|
||
_ => {
|
||
self.count -= 1;
|
||
self.iter.next_back()
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
generate_pattern_iterators! {
|
||
forward:
|
||
/// Created with the method [`splitn`].
|
||
///
|
||
/// [`splitn`]: ../../std/primitive.str.html#method.splitn
|
||
struct SplitN;
|
||
reverse:
|
||
/// Created with the method [`rsplitn`].
|
||
///
|
||
/// [`rsplitn`]: ../../std/primitive.str.html#method.rsplitn
|
||
struct RSplitN;
|
||
stability:
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
internal:
|
||
SplitNInternal yielding (&'a str);
|
||
delegate single ended;
|
||
}
|
||
|
||
derive_pattern_clone! {
|
||
clone MatchIndicesInternal
|
||
with |s| MatchIndicesInternal(s.0.clone())
|
||
}
|
||
|
||
struct MatchIndicesInternal<'a, P: Pattern<'a>>(P::Searcher);
|
||
|
||
impl<'a, P> fmt::Debug for MatchIndicesInternal<'a, P>
|
||
where
|
||
P: Pattern<'a, Searcher: fmt::Debug>,
|
||
{
|
||
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
||
f.debug_tuple("MatchIndicesInternal").field(&self.0).finish()
|
||
}
|
||
}
|
||
|
||
impl<'a, P: Pattern<'a>> MatchIndicesInternal<'a, P> {
|
||
#[inline]
|
||
fn next(&mut self) -> Option<(usize, &'a str)> {
|
||
self.0
|
||
.next_match()
|
||
// SAFETY: `Searcher` guarantees that `start` and `end` lie on unicode boundaries.
|
||
.map(|(start, end)| unsafe { (start, self.0.haystack().get_unchecked(start..end)) })
|
||
}
|
||
|
||
#[inline]
|
||
fn next_back(&mut self) -> Option<(usize, &'a str)>
|
||
where
|
||
P::Searcher: ReverseSearcher<'a>,
|
||
{
|
||
self.0
|
||
.next_match_back()
|
||
// SAFETY: `Searcher` guarantees that `start` and `end` lie on unicode boundaries.
|
||
.map(|(start, end)| unsafe { (start, self.0.haystack().get_unchecked(start..end)) })
|
||
}
|
||
}
|
||
|
||
generate_pattern_iterators! {
|
||
forward:
|
||
/// Created with the method [`match_indices`].
|
||
///
|
||
/// [`match_indices`]: ../../std/primitive.str.html#method.match_indices
|
||
struct MatchIndices;
|
||
reverse:
|
||
/// Created with the method [`rmatch_indices`].
|
||
///
|
||
/// [`rmatch_indices`]: ../../std/primitive.str.html#method.rmatch_indices
|
||
struct RMatchIndices;
|
||
stability:
|
||
#[stable(feature = "str_match_indices", since = "1.5.0")]
|
||
internal:
|
||
MatchIndicesInternal yielding ((usize, &'a str));
|
||
delegate double ended;
|
||
}
|
||
|
||
derive_pattern_clone! {
|
||
clone MatchesInternal
|
||
with |s| MatchesInternal(s.0.clone())
|
||
}
|
||
|
||
struct MatchesInternal<'a, P: Pattern<'a>>(P::Searcher);
|
||
|
||
impl<'a, P> fmt::Debug for MatchesInternal<'a, P>
|
||
where
|
||
P: Pattern<'a, Searcher: fmt::Debug>,
|
||
{
|
||
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
||
f.debug_tuple("MatchesInternal").field(&self.0).finish()
|
||
}
|
||
}
|
||
|
||
impl<'a, P: Pattern<'a>> MatchesInternal<'a, P> {
|
||
#[inline]
|
||
fn next(&mut self) -> Option<&'a str> {
|
||
// SAFETY: `Searcher` guarantees that `start` and `end` lie on unicode boundaries.
|
||
self.0.next_match().map(|(a, b)| unsafe {
|
||
// Indices are known to be on utf8 boundaries
|
||
self.0.haystack().get_unchecked(a..b)
|
||
})
|
||
}
|
||
|
||
#[inline]
|
||
fn next_back(&mut self) -> Option<&'a str>
|
||
where
|
||
P::Searcher: ReverseSearcher<'a>,
|
||
{
|
||
// SAFETY: `Searcher` guarantees that `start` and `end` lie on unicode boundaries.
|
||
self.0.next_match_back().map(|(a, b)| unsafe {
|
||
// Indices are known to be on utf8 boundaries
|
||
self.0.haystack().get_unchecked(a..b)
|
||
})
|
||
}
|
||
}
|
||
|
||
generate_pattern_iterators! {
|
||
forward:
|
||
/// Created with the method [`matches`].
|
||
///
|
||
/// [`matches`]: ../../std/primitive.str.html#method.matches
|
||
struct Matches;
|
||
reverse:
|
||
/// Created with the method [`rmatches`].
|
||
///
|
||
/// [`rmatches`]: ../../std/primitive.str.html#method.rmatches
|
||
struct RMatches;
|
||
stability:
|
||
#[stable(feature = "str_matches", since = "1.2.0")]
|
||
internal:
|
||
MatchesInternal yielding (&'a str);
|
||
delegate double ended;
|
||
}
|
||
|
||
/// An iterator over the lines of a string, as string slices.
|
||
///
|
||
/// This struct is created with the [`lines`] method on [`str`].
|
||
/// See its documentation for more.
|
||
///
|
||
/// [`lines`]: ../../std/primitive.str.html#method.lines
|
||
/// [`str`]: ../../std/primitive.str.html
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[derive(Clone, Debug)]
|
||
pub struct Lines<'a>(Map<SplitTerminator<'a, char>, LinesAnyMap>);
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<'a> Iterator for Lines<'a> {
|
||
type Item = &'a str;
|
||
|
||
#[inline]
|
||
fn next(&mut self) -> Option<&'a str> {
|
||
self.0.next()
|
||
}
|
||
|
||
#[inline]
|
||
fn size_hint(&self) -> (usize, Option<usize>) {
|
||
self.0.size_hint()
|
||
}
|
||
|
||
#[inline]
|
||
fn last(mut self) -> Option<&'a str> {
|
||
self.next_back()
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<'a> DoubleEndedIterator for Lines<'a> {
|
||
#[inline]
|
||
fn next_back(&mut self) -> Option<&'a str> {
|
||
self.0.next_back()
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "fused", since = "1.26.0")]
|
||
impl FusedIterator for Lines<'_> {}
|
||
|
||
/// Created with the method [`lines_any`].
|
||
///
|
||
/// [`lines_any`]: ../../std/primitive.str.html#method.lines_any
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[rustc_deprecated(since = "1.4.0", reason = "use lines()/Lines instead now")]
|
||
#[derive(Clone, Debug)]
|
||
#[allow(deprecated)]
|
||
pub struct LinesAny<'a>(Lines<'a>);
|
||
|
||
impl_fn_for_zst! {
|
||
/// A nameable, cloneable fn type
|
||
#[derive(Clone)]
|
||
struct LinesAnyMap impl<'a> Fn = |line: &'a str| -> &'a str {
|
||
let l = line.len();
|
||
if l > 0 && line.as_bytes()[l - 1] == b'\r' { &line[0 .. l - 1] }
|
||
else { line }
|
||
};
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[allow(deprecated)]
|
||
impl<'a> Iterator for LinesAny<'a> {
|
||
type Item = &'a str;
|
||
|
||
#[inline]
|
||
fn next(&mut self) -> Option<&'a str> {
|
||
self.0.next()
|
||
}
|
||
|
||
#[inline]
|
||
fn size_hint(&self) -> (usize, Option<usize>) {
|
||
self.0.size_hint()
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[allow(deprecated)]
|
||
impl<'a> DoubleEndedIterator for LinesAny<'a> {
|
||
#[inline]
|
||
fn next_back(&mut self) -> Option<&'a str> {
|
||
self.0.next_back()
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "fused", since = "1.26.0")]
|
||
#[allow(deprecated)]
|
||
impl FusedIterator for LinesAny<'_> {}
|
||
|
||
/*
|
||
Section: UTF-8 validation
|
||
*/
|
||
|
||
// use truncation to fit u64 into usize
|
||
const NONASCII_MASK: usize = 0x80808080_80808080u64 as usize;
|
||
|
||
/// Returns `true` if any byte in the word `x` is nonascii (>= 128).
|
||
#[inline]
|
||
fn contains_nonascii(x: usize) -> bool {
|
||
(x & NONASCII_MASK) != 0
|
||
}
|
||
|
||
/// Walks through `v` checking that it's a valid UTF-8 sequence,
|
||
/// returning `Ok(())` in that case, or, if it is invalid, `Err(err)`.
|
||
#[inline(always)]
|
||
fn run_utf8_validation(v: &[u8]) -> Result<(), Utf8Error> {
|
||
let mut index = 0;
|
||
let len = v.len();
|
||
|
||
let usize_bytes = mem::size_of::<usize>();
|
||
let ascii_block_size = 2 * usize_bytes;
|
||
let blocks_end = if len >= ascii_block_size { len - ascii_block_size + 1 } else { 0 };
|
||
let align = v.as_ptr().align_offset(usize_bytes);
|
||
|
||
while index < len {
|
||
let old_offset = index;
|
||
macro_rules! err {
|
||
($error_len: expr) => {
|
||
return Err(Utf8Error { valid_up_to: old_offset, error_len: $error_len });
|
||
};
|
||
}
|
||
|
||
macro_rules! next {
|
||
() => {{
|
||
index += 1;
|
||
// we needed data, but there was none: error!
|
||
if index >= len {
|
||
err!(None)
|
||
}
|
||
v[index]
|
||
}};
|
||
}
|
||
|
||
let first = v[index];
|
||
if first >= 128 {
|
||
let w = UTF8_CHAR_WIDTH[first as usize];
|
||
// 2-byte encoding is for codepoints \u{0080} to \u{07ff}
|
||
// first C2 80 last DF BF
|
||
// 3-byte encoding is for codepoints \u{0800} to \u{ffff}
|
||
// first E0 A0 80 last EF BF BF
|
||
// excluding surrogates codepoints \u{d800} to \u{dfff}
|
||
// ED A0 80 to ED BF BF
|
||
// 4-byte encoding is for codepoints \u{1000}0 to \u{10ff}ff
|
||
// first F0 90 80 80 last F4 8F BF BF
|
||
//
|
||
// Use the UTF-8 syntax from the RFC
|
||
//
|
||
// https://tools.ietf.org/html/rfc3629
|
||
// UTF8-1 = %x00-7F
|
||
// UTF8-2 = %xC2-DF UTF8-tail
|
||
// UTF8-3 = %xE0 %xA0-BF UTF8-tail / %xE1-EC 2( UTF8-tail ) /
|
||
// %xED %x80-9F UTF8-tail / %xEE-EF 2( UTF8-tail )
|
||
// UTF8-4 = %xF0 %x90-BF 2( UTF8-tail ) / %xF1-F3 3( UTF8-tail ) /
|
||
// %xF4 %x80-8F 2( UTF8-tail )
|
||
match w {
|
||
2 => {
|
||
if next!() & !CONT_MASK != TAG_CONT_U8 {
|
||
err!(Some(1))
|
||
}
|
||
}
|
||
3 => {
|
||
match (first, next!()) {
|
||
(0xE0, 0xA0..=0xBF)
|
||
| (0xE1..=0xEC, 0x80..=0xBF)
|
||
| (0xED, 0x80..=0x9F)
|
||
| (0xEE..=0xEF, 0x80..=0xBF) => {}
|
||
_ => err!(Some(1)),
|
||
}
|
||
if next!() & !CONT_MASK != TAG_CONT_U8 {
|
||
err!(Some(2))
|
||
}
|
||
}
|
||
4 => {
|
||
match (first, next!()) {
|
||
(0xF0, 0x90..=0xBF) | (0xF1..=0xF3, 0x80..=0xBF) | (0xF4, 0x80..=0x8F) => {}
|
||
_ => err!(Some(1)),
|
||
}
|
||
if next!() & !CONT_MASK != TAG_CONT_U8 {
|
||
err!(Some(2))
|
||
}
|
||
if next!() & !CONT_MASK != TAG_CONT_U8 {
|
||
err!(Some(3))
|
||
}
|
||
}
|
||
_ => err!(Some(1)),
|
||
}
|
||
index += 1;
|
||
} else {
|
||
// Ascii case, try to skip forward quickly.
|
||
// When the pointer is aligned, read 2 words of data per iteration
|
||
// until we find a word containing a non-ascii byte.
|
||
if align != usize::max_value() && align.wrapping_sub(index) % usize_bytes == 0 {
|
||
let ptr = v.as_ptr();
|
||
while index < blocks_end {
|
||
// SAFETY: since `align - index` and `ascii_block_size` are
|
||
// multiples of `usize_bytes`, `block = ptr.add(index)` is
|
||
// always aligned with a `usize` so it's safe to dereference
|
||
// both `block` and `block.offset(1)`.
|
||
unsafe {
|
||
let block = ptr.add(index) as *const usize;
|
||
// break if there is a nonascii byte
|
||
let zu = contains_nonascii(*block);
|
||
let zv = contains_nonascii(*block.offset(1));
|
||
if zu | zv {
|
||
break;
|
||
}
|
||
}
|
||
index += ascii_block_size;
|
||
}
|
||
// step from the point where the wordwise loop stopped
|
||
while index < len && v[index] < 128 {
|
||
index += 1;
|
||
}
|
||
} else {
|
||
index += 1;
|
||
}
|
||
}
|
||
}
|
||
|
||
Ok(())
|
||
}
|
||
|
||
// https://tools.ietf.org/html/rfc3629
|
||
static UTF8_CHAR_WIDTH: [u8; 256] = [
|
||
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
|
||
1, // 0x1F
|
||
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
|
||
1, // 0x3F
|
||
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
|
||
1, // 0x5F
|
||
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
|
||
1, // 0x7F
|
||
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
|
||
0, // 0x9F
|
||
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
|
||
0, // 0xBF
|
||
0, 0, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
|
||
2, // 0xDF
|
||
3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, // 0xEF
|
||
4, 4, 4, 4, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 0xFF
|
||
];
|
||
|
||
/// Given a first byte, determines how many bytes are in this UTF-8 character.
|
||
#[unstable(feature = "str_internals", issue = "none")]
|
||
#[inline]
|
||
pub fn utf8_char_width(b: u8) -> usize {
|
||
UTF8_CHAR_WIDTH[b as usize] as usize
|
||
}
|
||
|
||
/// Mask of the value bits of a continuation byte.
|
||
const CONT_MASK: u8 = 0b0011_1111;
|
||
/// Value of the tag bits (tag mask is !CONT_MASK) of a continuation byte.
|
||
const TAG_CONT_U8: u8 = 0b1000_0000;
|
||
|
||
/*
|
||
Section: Trait implementations
|
||
*/
|
||
|
||
mod traits {
|
||
use crate::cmp::Ordering;
|
||
use crate::ops;
|
||
use crate::slice::{self, SliceIndex};
|
||
|
||
/// Implements ordering of strings.
|
||
///
|
||
/// Strings are ordered lexicographically by their byte values. This orders Unicode code
|
||
/// points based on their positions in the code charts. This is not necessarily the same as
|
||
/// "alphabetical" order, which varies by language and locale. Sorting strings according to
|
||
/// culturally-accepted standards requires locale-specific data that is outside the scope of
|
||
/// the `str` type.
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl Ord for str {
|
||
#[inline]
|
||
fn cmp(&self, other: &str) -> Ordering {
|
||
self.as_bytes().cmp(other.as_bytes())
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl PartialEq for str {
|
||
#[inline]
|
||
fn eq(&self, other: &str) -> bool {
|
||
self.as_bytes() == other.as_bytes()
|
||
}
|
||
#[inline]
|
||
fn ne(&self, other: &str) -> bool {
|
||
!(*self).eq(other)
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl Eq for str {}
|
||
|
||
/// Implements comparison operations on strings.
|
||
///
|
||
/// Strings are compared lexicographically by their byte values. This compares Unicode code
|
||
/// points based on their positions in the code charts. This is not necessarily the same as
|
||
/// "alphabetical" order, which varies by language and locale. Comparing strings according to
|
||
/// culturally-accepted standards requires locale-specific data that is outside the scope of
|
||
/// the `str` type.
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl PartialOrd for str {
|
||
#[inline]
|
||
fn partial_cmp(&self, other: &str) -> Option<Ordering> {
|
||
Some(self.cmp(other))
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<I> ops::Index<I> for str
|
||
where
|
||
I: SliceIndex<str>,
|
||
{
|
||
type Output = I::Output;
|
||
|
||
#[inline]
|
||
fn index(&self, index: I) -> &I::Output {
|
||
index.index(self)
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl<I> ops::IndexMut<I> for str
|
||
where
|
||
I: SliceIndex<str>,
|
||
{
|
||
#[inline]
|
||
fn index_mut(&mut self, index: I) -> &mut I::Output {
|
||
index.index_mut(self)
|
||
}
|
||
}
|
||
|
||
#[inline(never)]
|
||
#[cold]
|
||
fn str_index_overflow_fail() -> ! {
|
||
panic!("attempted to index str up to maximum usize");
|
||
}
|
||
|
||
/// Implements substring slicing with syntax `&self[..]` or `&mut self[..]`.
|
||
///
|
||
/// Returns a slice of the whole string, i.e., returns `&self` or `&mut
|
||
/// self`. Equivalent to `&self[0 .. len]` or `&mut self[0 .. len]`. Unlike
|
||
/// other indexing operations, this can never panic.
|
||
///
|
||
/// This operation is `O(1)`.
|
||
///
|
||
/// Prior to 1.20.0, these indexing operations were still supported by
|
||
/// direct implementation of `Index` and `IndexMut`.
|
||
///
|
||
/// Equivalent to `&self[0 .. len]` or `&mut self[0 .. len]`.
|
||
#[stable(feature = "str_checked_slicing", since = "1.20.0")]
|
||
impl SliceIndex<str> for ops::RangeFull {
|
||
type Output = str;
|
||
#[inline]
|
||
fn get(self, slice: &str) -> Option<&Self::Output> {
|
||
Some(slice)
|
||
}
|
||
#[inline]
|
||
fn get_mut(self, slice: &mut str) -> Option<&mut Self::Output> {
|
||
Some(slice)
|
||
}
|
||
#[inline]
|
||
unsafe fn get_unchecked(self, slice: &str) -> &Self::Output {
|
||
slice
|
||
}
|
||
#[inline]
|
||
unsafe fn get_unchecked_mut(self, slice: &mut str) -> &mut Self::Output {
|
||
slice
|
||
}
|
||
#[inline]
|
||
fn index(self, slice: &str) -> &Self::Output {
|
||
slice
|
||
}
|
||
#[inline]
|
||
fn index_mut(self, slice: &mut str) -> &mut Self::Output {
|
||
slice
|
||
}
|
||
}
|
||
|
||
/// Implements substring slicing with syntax `&self[begin .. end]` or `&mut
|
||
/// self[begin .. end]`.
|
||
///
|
||
/// Returns a slice of the given string from the byte range
|
||
/// [`begin`, `end`).
|
||
///
|
||
/// This operation is `O(1)`.
|
||
///
|
||
/// Prior to 1.20.0, these indexing operations were still supported by
|
||
/// direct implementation of `Index` and `IndexMut`.
|
||
///
|
||
/// # Panics
|
||
///
|
||
/// Panics if `begin` or `end` does not point to the starting byte offset of
|
||
/// a character (as defined by `is_char_boundary`), if `begin > end`, or if
|
||
/// `end > len`.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// let s = "Löwe 老虎 Léopard";
|
||
/// assert_eq!(&s[0 .. 1], "L");
|
||
///
|
||
/// assert_eq!(&s[1 .. 9], "öwe 老");
|
||
///
|
||
/// // these will panic:
|
||
/// // byte 2 lies within `ö`:
|
||
/// // &s[2 ..3];
|
||
///
|
||
/// // byte 8 lies within `老`
|
||
/// // &s[1 .. 8];
|
||
///
|
||
/// // byte 100 is outside the string
|
||
/// // &s[3 .. 100];
|
||
/// ```
|
||
#[stable(feature = "str_checked_slicing", since = "1.20.0")]
|
||
impl SliceIndex<str> for ops::Range<usize> {
|
||
type Output = str;
|
||
#[inline]
|
||
fn get(self, slice: &str) -> Option<&Self::Output> {
|
||
if self.start <= self.end
|
||
&& slice.is_char_boundary(self.start)
|
||
&& slice.is_char_boundary(self.end)
|
||
{
|
||
// SAFETY: just checked that `start` and `end` are on a char boundary.
|
||
Some(unsafe { self.get_unchecked(slice) })
|
||
} else {
|
||
None
|
||
}
|
||
}
|
||
#[inline]
|
||
fn get_mut(self, slice: &mut str) -> Option<&mut Self::Output> {
|
||
if self.start <= self.end
|
||
&& slice.is_char_boundary(self.start)
|
||
&& slice.is_char_boundary(self.end)
|
||
{
|
||
// SAFETY: just checked that `start` and `end` are on a char boundary.
|
||
Some(unsafe { self.get_unchecked_mut(slice) })
|
||
} else {
|
||
None
|
||
}
|
||
}
|
||
#[inline]
|
||
unsafe fn get_unchecked(self, slice: &str) -> &Self::Output {
|
||
let ptr = slice.as_ptr().add(self.start);
|
||
let len = self.end - self.start;
|
||
super::from_utf8_unchecked(slice::from_raw_parts(ptr, len))
|
||
}
|
||
#[inline]
|
||
unsafe fn get_unchecked_mut(self, slice: &mut str) -> &mut Self::Output {
|
||
let ptr = slice.as_mut_ptr().add(self.start);
|
||
let len = self.end - self.start;
|
||
super::from_utf8_unchecked_mut(slice::from_raw_parts_mut(ptr, len))
|
||
}
|
||
#[inline]
|
||
fn index(self, slice: &str) -> &Self::Output {
|
||
let (start, end) = (self.start, self.end);
|
||
self.get(slice).unwrap_or_else(|| super::slice_error_fail(slice, start, end))
|
||
}
|
||
#[inline]
|
||
fn index_mut(self, slice: &mut str) -> &mut Self::Output {
|
||
// is_char_boundary checks that the index is in [0, .len()]
|
||
// cannot reuse `get` as above, because of NLL trouble
|
||
if self.start <= self.end
|
||
&& slice.is_char_boundary(self.start)
|
||
&& slice.is_char_boundary(self.end)
|
||
{
|
||
// SAFETY: just checked that `start` and `end` are on a char boundary.
|
||
unsafe { self.get_unchecked_mut(slice) }
|
||
} else {
|
||
super::slice_error_fail(slice, self.start, self.end)
|
||
}
|
||
}
|
||
}
|
||
|
||
/// Implements substring slicing with syntax `&self[.. end]` or `&mut
|
||
/// self[.. end]`.
|
||
///
|
||
/// Returns a slice of the given string from the byte range [`0`, `end`).
|
||
/// Equivalent to `&self[0 .. end]` or `&mut self[0 .. end]`.
|
||
///
|
||
/// This operation is `O(1)`.
|
||
///
|
||
/// Prior to 1.20.0, these indexing operations were still supported by
|
||
/// direct implementation of `Index` and `IndexMut`.
|
||
///
|
||
/// # Panics
|
||
///
|
||
/// Panics if `end` does not point to the starting byte offset of a
|
||
/// character (as defined by `is_char_boundary`), or if `end > len`.
|
||
#[stable(feature = "str_checked_slicing", since = "1.20.0")]
|
||
impl SliceIndex<str> for ops::RangeTo<usize> {
|
||
type Output = str;
|
||
#[inline]
|
||
fn get(self, slice: &str) -> Option<&Self::Output> {
|
||
if slice.is_char_boundary(self.end) {
|
||
// SAFETY: just checked that `end` is on a char boundary.
|
||
Some(unsafe { self.get_unchecked(slice) })
|
||
} else {
|
||
None
|
||
}
|
||
}
|
||
#[inline]
|
||
fn get_mut(self, slice: &mut str) -> Option<&mut Self::Output> {
|
||
if slice.is_char_boundary(self.end) {
|
||
// SAFETY: just checked that `end` is on a char boundary.
|
||
Some(unsafe { self.get_unchecked_mut(slice) })
|
||
} else {
|
||
None
|
||
}
|
||
}
|
||
#[inline]
|
||
unsafe fn get_unchecked(self, slice: &str) -> &Self::Output {
|
||
let ptr = slice.as_ptr();
|
||
super::from_utf8_unchecked(slice::from_raw_parts(ptr, self.end))
|
||
}
|
||
#[inline]
|
||
unsafe fn get_unchecked_mut(self, slice: &mut str) -> &mut Self::Output {
|
||
let ptr = slice.as_mut_ptr();
|
||
super::from_utf8_unchecked_mut(slice::from_raw_parts_mut(ptr, self.end))
|
||
}
|
||
#[inline]
|
||
fn index(self, slice: &str) -> &Self::Output {
|
||
let end = self.end;
|
||
self.get(slice).unwrap_or_else(|| super::slice_error_fail(slice, 0, end))
|
||
}
|
||
#[inline]
|
||
fn index_mut(self, slice: &mut str) -> &mut Self::Output {
|
||
if slice.is_char_boundary(self.end) {
|
||
// SAFETY: just checked that `end` is on a char boundary.
|
||
unsafe { self.get_unchecked_mut(slice) }
|
||
} else {
|
||
super::slice_error_fail(slice, 0, self.end)
|
||
}
|
||
}
|
||
}
|
||
|
||
/// Implements substring slicing with syntax `&self[begin ..]` or `&mut
|
||
/// self[begin ..]`.
|
||
///
|
||
/// Returns a slice of the given string from the byte range [`begin`,
|
||
/// `len`). Equivalent to `&self[begin .. len]` or `&mut self[begin ..
|
||
/// len]`.
|
||
///
|
||
/// This operation is `O(1)`.
|
||
///
|
||
/// Prior to 1.20.0, these indexing operations were still supported by
|
||
/// direct implementation of `Index` and `IndexMut`.
|
||
///
|
||
/// # Panics
|
||
///
|
||
/// Panics if `begin` does not point to the starting byte offset of
|
||
/// a character (as defined by `is_char_boundary`), or if `begin >= len`.
|
||
#[stable(feature = "str_checked_slicing", since = "1.20.0")]
|
||
impl SliceIndex<str> for ops::RangeFrom<usize> {
|
||
type Output = str;
|
||
#[inline]
|
||
fn get(self, slice: &str) -> Option<&Self::Output> {
|
||
if slice.is_char_boundary(self.start) {
|
||
// SAFETY: just checked that `start` is on a char boundary.
|
||
Some(unsafe { self.get_unchecked(slice) })
|
||
} else {
|
||
None
|
||
}
|
||
}
|
||
#[inline]
|
||
fn get_mut(self, slice: &mut str) -> Option<&mut Self::Output> {
|
||
if slice.is_char_boundary(self.start) {
|
||
// SAFETY: just checked that `start` is on a char boundary.
|
||
Some(unsafe { self.get_unchecked_mut(slice) })
|
||
} else {
|
||
None
|
||
}
|
||
}
|
||
#[inline]
|
||
unsafe fn get_unchecked(self, slice: &str) -> &Self::Output {
|
||
let ptr = slice.as_ptr().add(self.start);
|
||
let len = slice.len() - self.start;
|
||
super::from_utf8_unchecked(slice::from_raw_parts(ptr, len))
|
||
}
|
||
#[inline]
|
||
unsafe fn get_unchecked_mut(self, slice: &mut str) -> &mut Self::Output {
|
||
let ptr = slice.as_mut_ptr().add(self.start);
|
||
let len = slice.len() - self.start;
|
||
super::from_utf8_unchecked_mut(slice::from_raw_parts_mut(ptr, len))
|
||
}
|
||
#[inline]
|
||
fn index(self, slice: &str) -> &Self::Output {
|
||
let (start, end) = (self.start, slice.len());
|
||
self.get(slice).unwrap_or_else(|| super::slice_error_fail(slice, start, end))
|
||
}
|
||
#[inline]
|
||
fn index_mut(self, slice: &mut str) -> &mut Self::Output {
|
||
if slice.is_char_boundary(self.start) {
|
||
// SAFETY: just checked that `start` is on a char boundary.
|
||
unsafe { self.get_unchecked_mut(slice) }
|
||
} else {
|
||
super::slice_error_fail(slice, self.start, slice.len())
|
||
}
|
||
}
|
||
}
|
||
|
||
/// Implements substring slicing with syntax `&self[begin ..= end]` or `&mut
|
||
/// self[begin ..= end]`.
|
||
///
|
||
/// Returns a slice of the given string from the byte range
|
||
/// [`begin`, `end`]. Equivalent to `&self [begin .. end + 1]` or `&mut
|
||
/// self[begin .. end + 1]`, except if `end` has the maximum value for
|
||
/// `usize`.
|
||
///
|
||
/// This operation is `O(1)`.
|
||
///
|
||
/// # Panics
|
||
///
|
||
/// Panics if `begin` does not point to the starting byte offset of
|
||
/// a character (as defined by `is_char_boundary`), if `end` does not point
|
||
/// to the ending byte offset of a character (`end + 1` is either a starting
|
||
/// byte offset or equal to `len`), if `begin > end`, or if `end >= len`.
|
||
#[stable(feature = "inclusive_range", since = "1.26.0")]
|
||
impl SliceIndex<str> for ops::RangeInclusive<usize> {
|
||
type Output = str;
|
||
#[inline]
|
||
fn get(self, slice: &str) -> Option<&Self::Output> {
|
||
if *self.end() == usize::max_value() {
|
||
None
|
||
} else {
|
||
(*self.start()..self.end() + 1).get(slice)
|
||
}
|
||
}
|
||
#[inline]
|
||
fn get_mut(self, slice: &mut str) -> Option<&mut Self::Output> {
|
||
if *self.end() == usize::max_value() {
|
||
None
|
||
} else {
|
||
(*self.start()..self.end() + 1).get_mut(slice)
|
||
}
|
||
}
|
||
#[inline]
|
||
unsafe fn get_unchecked(self, slice: &str) -> &Self::Output {
|
||
(*self.start()..self.end() + 1).get_unchecked(slice)
|
||
}
|
||
#[inline]
|
||
unsafe fn get_unchecked_mut(self, slice: &mut str) -> &mut Self::Output {
|
||
(*self.start()..self.end() + 1).get_unchecked_mut(slice)
|
||
}
|
||
#[inline]
|
||
fn index(self, slice: &str) -> &Self::Output {
|
||
if *self.end() == usize::max_value() {
|
||
str_index_overflow_fail();
|
||
}
|
||
(*self.start()..self.end() + 1).index(slice)
|
||
}
|
||
#[inline]
|
||
fn index_mut(self, slice: &mut str) -> &mut Self::Output {
|
||
if *self.end() == usize::max_value() {
|
||
str_index_overflow_fail();
|
||
}
|
||
(*self.start()..self.end() + 1).index_mut(slice)
|
||
}
|
||
}
|
||
|
||
/// Implements substring slicing with syntax `&self[..= end]` or `&mut
|
||
/// self[..= end]`.
|
||
///
|
||
/// Returns a slice of the given string from the byte range [0, `end`].
|
||
/// Equivalent to `&self [0 .. end + 1]`, except if `end` has the maximum
|
||
/// value for `usize`.
|
||
///
|
||
/// This operation is `O(1)`.
|
||
///
|
||
/// # Panics
|
||
///
|
||
/// Panics if `end` does not point to the ending byte offset of a character
|
||
/// (`end + 1` is either a starting byte offset as defined by
|
||
/// `is_char_boundary`, or equal to `len`), or if `end >= len`.
|
||
#[stable(feature = "inclusive_range", since = "1.26.0")]
|
||
impl SliceIndex<str> for ops::RangeToInclusive<usize> {
|
||
type Output = str;
|
||
#[inline]
|
||
fn get(self, slice: &str) -> Option<&Self::Output> {
|
||
if self.end == usize::max_value() { None } else { (..self.end + 1).get(slice) }
|
||
}
|
||
#[inline]
|
||
fn get_mut(self, slice: &mut str) -> Option<&mut Self::Output> {
|
||
if self.end == usize::max_value() { None } else { (..self.end + 1).get_mut(slice) }
|
||
}
|
||
#[inline]
|
||
unsafe fn get_unchecked(self, slice: &str) -> &Self::Output {
|
||
(..self.end + 1).get_unchecked(slice)
|
||
}
|
||
#[inline]
|
||
unsafe fn get_unchecked_mut(self, slice: &mut str) -> &mut Self::Output {
|
||
(..self.end + 1).get_unchecked_mut(slice)
|
||
}
|
||
#[inline]
|
||
fn index(self, slice: &str) -> &Self::Output {
|
||
if self.end == usize::max_value() {
|
||
str_index_overflow_fail();
|
||
}
|
||
(..self.end + 1).index(slice)
|
||
}
|
||
#[inline]
|
||
fn index_mut(self, slice: &mut str) -> &mut Self::Output {
|
||
if self.end == usize::max_value() {
|
||
str_index_overflow_fail();
|
||
}
|
||
(..self.end + 1).index_mut(slice)
|
||
}
|
||
}
|
||
}
|
||
|
||
// truncate `&str` to length at most equal to `max`
|
||
// return `true` if it were truncated, and the new str.
|
||
fn truncate_to_char_boundary(s: &str, mut max: usize) -> (bool, &str) {
|
||
if max >= s.len() {
|
||
(false, s)
|
||
} else {
|
||
while !s.is_char_boundary(max) {
|
||
max -= 1;
|
||
}
|
||
(true, &s[..max])
|
||
}
|
||
}
|
||
|
||
#[inline(never)]
|
||
#[cold]
|
||
fn slice_error_fail(s: &str, begin: usize, end: usize) -> ! {
|
||
const MAX_DISPLAY_LENGTH: usize = 256;
|
||
let (truncated, s_trunc) = truncate_to_char_boundary(s, MAX_DISPLAY_LENGTH);
|
||
let ellipsis = if truncated { "[...]" } else { "" };
|
||
|
||
// 1. out of bounds
|
||
if begin > s.len() || end > s.len() {
|
||
let oob_index = if begin > s.len() { begin } else { end };
|
||
panic!("byte index {} is out of bounds of `{}`{}", oob_index, s_trunc, ellipsis);
|
||
}
|
||
|
||
// 2. begin <= end
|
||
assert!(
|
||
begin <= end,
|
||
"begin <= end ({} <= {}) when slicing `{}`{}",
|
||
begin,
|
||
end,
|
||
s_trunc,
|
||
ellipsis
|
||
);
|
||
|
||
// 3. character boundary
|
||
let index = if !s.is_char_boundary(begin) { begin } else { end };
|
||
// find the character
|
||
let mut char_start = index;
|
||
while !s.is_char_boundary(char_start) {
|
||
char_start -= 1;
|
||
}
|
||
// `char_start` must be less than len and a char boundary
|
||
let ch = s[char_start..].chars().next().unwrap();
|
||
let char_range = char_start..char_start + ch.len_utf8();
|
||
panic!(
|
||
"byte index {} is not a char boundary; it is inside {:?} (bytes {:?}) of `{}`{}",
|
||
index, ch, char_range, s_trunc, ellipsis
|
||
);
|
||
}
|
||
|
||
#[lang = "str"]
|
||
#[cfg(not(test))]
|
||
impl str {
|
||
/// Returns the length of `self`.
|
||
///
|
||
/// This length is in bytes, not [`char`]s or graphemes. In other words,
|
||
/// it may not be what a human considers the length of the string.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// let len = "foo".len();
|
||
/// assert_eq!(3, len);
|
||
///
|
||
/// assert_eq!("ƒoo".len(), 4); // fancy f!
|
||
/// assert_eq!("ƒoo".chars().count(), 3);
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[rustc_const_stable(feature = "const_str_len", since = "1.32.0")]
|
||
#[inline]
|
||
pub const fn len(&self) -> usize {
|
||
self.as_bytes().len()
|
||
}
|
||
|
||
/// Returns `true` if `self` has a length of zero bytes.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// let s = "";
|
||
/// assert!(s.is_empty());
|
||
///
|
||
/// let s = "not empty";
|
||
/// assert!(!s.is_empty());
|
||
/// ```
|
||
#[inline]
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[rustc_const_stable(feature = "const_str_is_empty", since = "1.32.0")]
|
||
pub const fn is_empty(&self) -> bool {
|
||
self.len() == 0
|
||
}
|
||
|
||
/// Checks that `index`-th byte lies at the start and/or end of a
|
||
/// UTF-8 code point sequence.
|
||
///
|
||
/// The start and end of the string (when `index == self.len()`) are
|
||
/// considered to be
|
||
/// boundaries.
|
||
///
|
||
/// Returns `false` if `index` is greater than `self.len()`.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// let s = "Löwe 老虎 Léopard";
|
||
/// assert!(s.is_char_boundary(0));
|
||
/// // start of `老`
|
||
/// assert!(s.is_char_boundary(6));
|
||
/// assert!(s.is_char_boundary(s.len()));
|
||
///
|
||
/// // second byte of `ö`
|
||
/// assert!(!s.is_char_boundary(2));
|
||
///
|
||
/// // third byte of `老`
|
||
/// assert!(!s.is_char_boundary(8));
|
||
/// ```
|
||
#[stable(feature = "is_char_boundary", since = "1.9.0")]
|
||
#[inline]
|
||
pub fn is_char_boundary(&self, index: usize) -> bool {
|
||
// 0 and len are always ok.
|
||
// Test for 0 explicitly so that it can optimize out the check
|
||
// easily and skip reading string data for that case.
|
||
if index == 0 || index == self.len() {
|
||
return true;
|
||
}
|
||
match self.as_bytes().get(index) {
|
||
None => false,
|
||
// This is bit magic equivalent to: b < 128 || b >= 192
|
||
Some(&b) => (b as i8) >= -0x40,
|
||
}
|
||
}
|
||
|
||
/// Converts a string slice to a byte slice. To convert the byte slice back
|
||
/// into a string slice, use the [`str::from_utf8`] function.
|
||
///
|
||
/// [`str::from_utf8`]: ./str/fn.from_utf8.html
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// let bytes = "bors".as_bytes();
|
||
/// assert_eq!(b"bors", bytes);
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[rustc_const_stable(feature = "str_as_bytes", since = "1.32.0")]
|
||
#[inline(always)]
|
||
#[allow(unused_attributes)]
|
||
#[allow_internal_unstable(const_fn_union)]
|
||
pub const fn as_bytes(&self) -> &[u8] {
|
||
#[repr(C)]
|
||
union Slices<'a> {
|
||
str: &'a str,
|
||
slice: &'a [u8],
|
||
}
|
||
// SAFETY: const sound because we transmute two types with the same layout
|
||
unsafe { Slices { str: self }.slice }
|
||
}
|
||
|
||
/// Converts a mutable string slice to a mutable byte slice. To convert the
|
||
/// mutable byte slice back into a mutable string slice, use the
|
||
/// [`str::from_utf8_mut`] function.
|
||
///
|
||
/// [`str::from_utf8_mut`]: ./str/fn.from_utf8_mut.html
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// let mut s = String::from("Hello");
|
||
/// let bytes = unsafe { s.as_bytes_mut() };
|
||
///
|
||
/// assert_eq!(b"Hello", bytes);
|
||
/// ```
|
||
///
|
||
/// Mutability:
|
||
///
|
||
/// ```
|
||
/// let mut s = String::from("🗻∈🌏");
|
||
///
|
||
/// unsafe {
|
||
/// let bytes = s.as_bytes_mut();
|
||
///
|
||
/// bytes[0] = 0xF0;
|
||
/// bytes[1] = 0x9F;
|
||
/// bytes[2] = 0x8D;
|
||
/// bytes[3] = 0x94;
|
||
/// }
|
||
///
|
||
/// assert_eq!("🍔∈🌏", s);
|
||
/// ```
|
||
#[stable(feature = "str_mut_extras", since = "1.20.0")]
|
||
#[inline(always)]
|
||
pub unsafe fn as_bytes_mut(&mut self) -> &mut [u8] {
|
||
&mut *(self as *mut str as *mut [u8])
|
||
}
|
||
|
||
/// Converts a string slice to a raw pointer.
|
||
///
|
||
/// As string slices are a slice of bytes, the raw pointer points to a
|
||
/// [`u8`]. This pointer will be pointing to the first byte of the string
|
||
/// slice.
|
||
///
|
||
/// The caller must ensure that the returned pointer is never written to.
|
||
/// If you need to mutate the contents of the string slice, use [`as_mut_ptr`].
|
||
///
|
||
/// [`u8`]: primitive.u8.html
|
||
/// [`as_mut_ptr`]: #method.as_mut_ptr
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// let s = "Hello";
|
||
/// let ptr = s.as_ptr();
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[rustc_const_stable(feature = "rustc_str_as_ptr", since = "1.32.0")]
|
||
#[inline]
|
||
pub const fn as_ptr(&self) -> *const u8 {
|
||
self as *const str as *const u8
|
||
}
|
||
|
||
/// Converts a mutable string slice to a raw pointer.
|
||
///
|
||
/// As string slices are a slice of bytes, the raw pointer points to a
|
||
/// [`u8`]. This pointer will be pointing to the first byte of the string
|
||
/// slice.
|
||
///
|
||
/// It is your responsibility to make sure that the string slice only gets
|
||
/// modified in a way that it remains valid UTF-8.
|
||
///
|
||
/// [`u8`]: primitive.u8.html
|
||
#[stable(feature = "str_as_mut_ptr", since = "1.36.0")]
|
||
#[inline]
|
||
pub fn as_mut_ptr(&mut self) -> *mut u8 {
|
||
self as *mut str as *mut u8
|
||
}
|
||
|
||
/// Returns a subslice of `str`.
|
||
///
|
||
/// This is the non-panicking alternative to indexing the `str`. Returns
|
||
/// [`None`] whenever equivalent indexing operation would panic.
|
||
///
|
||
/// [`None`]: option/enum.Option.html#variant.None
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// let v = String::from("🗻∈🌏");
|
||
///
|
||
/// assert_eq!(Some("🗻"), v.get(0..4));
|
||
///
|
||
/// // indices not on UTF-8 sequence boundaries
|
||
/// assert!(v.get(1..).is_none());
|
||
/// assert!(v.get(..8).is_none());
|
||
///
|
||
/// // out of bounds
|
||
/// assert!(v.get(..42).is_none());
|
||
/// ```
|
||
#[stable(feature = "str_checked_slicing", since = "1.20.0")]
|
||
#[inline]
|
||
pub fn get<I: SliceIndex<str>>(&self, i: I) -> Option<&I::Output> {
|
||
i.get(self)
|
||
}
|
||
|
||
/// Returns a mutable subslice of `str`.
|
||
///
|
||
/// This is the non-panicking alternative to indexing the `str`. Returns
|
||
/// [`None`] whenever equivalent indexing operation would panic.
|
||
///
|
||
/// [`None`]: option/enum.Option.html#variant.None
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// let mut v = String::from("hello");
|
||
/// // correct length
|
||
/// assert!(v.get_mut(0..5).is_some());
|
||
/// // out of bounds
|
||
/// assert!(v.get_mut(..42).is_none());
|
||
/// assert_eq!(Some("he"), v.get_mut(0..2).map(|v| &*v));
|
||
///
|
||
/// assert_eq!("hello", v);
|
||
/// {
|
||
/// let s = v.get_mut(0..2);
|
||
/// let s = s.map(|s| {
|
||
/// s.make_ascii_uppercase();
|
||
/// &*s
|
||
/// });
|
||
/// assert_eq!(Some("HE"), s);
|
||
/// }
|
||
/// assert_eq!("HEllo", v);
|
||
/// ```
|
||
#[stable(feature = "str_checked_slicing", since = "1.20.0")]
|
||
#[inline]
|
||
pub fn get_mut<I: SliceIndex<str>>(&mut self, i: I) -> Option<&mut I::Output> {
|
||
i.get_mut(self)
|
||
}
|
||
|
||
/// Returns an unchecked subslice of `str`.
|
||
///
|
||
/// This is the unchecked alternative to indexing the `str`.
|
||
///
|
||
/// # Safety
|
||
///
|
||
/// Callers of this function are responsible that these preconditions are
|
||
/// satisfied:
|
||
///
|
||
/// * The starting index must come before the ending index;
|
||
/// * Indexes must be within bounds of the original slice;
|
||
/// * Indexes must lie on UTF-8 sequence boundaries.
|
||
///
|
||
/// Failing that, the returned string slice may reference invalid memory or
|
||
/// violate the invariants communicated by the `str` type.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// let v = "🗻∈🌏";
|
||
/// unsafe {
|
||
/// assert_eq!("🗻", v.get_unchecked(0..4));
|
||
/// assert_eq!("∈", v.get_unchecked(4..7));
|
||
/// assert_eq!("🌏", v.get_unchecked(7..11));
|
||
/// }
|
||
/// ```
|
||
#[stable(feature = "str_checked_slicing", since = "1.20.0")]
|
||
#[inline]
|
||
pub unsafe fn get_unchecked<I: SliceIndex<str>>(&self, i: I) -> &I::Output {
|
||
i.get_unchecked(self)
|
||
}
|
||
|
||
/// Returns a mutable, unchecked subslice of `str`.
|
||
///
|
||
/// This is the unchecked alternative to indexing the `str`.
|
||
///
|
||
/// # Safety
|
||
///
|
||
/// Callers of this function are responsible that these preconditions are
|
||
/// satisfied:
|
||
///
|
||
/// * The starting index must come before the ending index;
|
||
/// * Indexes must be within bounds of the original slice;
|
||
/// * Indexes must lie on UTF-8 sequence boundaries.
|
||
///
|
||
/// Failing that, the returned string slice may reference invalid memory or
|
||
/// violate the invariants communicated by the `str` type.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// let mut v = String::from("🗻∈🌏");
|
||
/// unsafe {
|
||
/// assert_eq!("🗻", v.get_unchecked_mut(0..4));
|
||
/// assert_eq!("∈", v.get_unchecked_mut(4..7));
|
||
/// assert_eq!("🌏", v.get_unchecked_mut(7..11));
|
||
/// }
|
||
/// ```
|
||
#[stable(feature = "str_checked_slicing", since = "1.20.0")]
|
||
#[inline]
|
||
pub unsafe fn get_unchecked_mut<I: SliceIndex<str>>(&mut self, i: I) -> &mut I::Output {
|
||
i.get_unchecked_mut(self)
|
||
}
|
||
|
||
/// Creates a string slice from another string slice, bypassing safety
|
||
/// checks.
|
||
///
|
||
/// This is generally not recommended, use with caution! For a safe
|
||
/// alternative see [`str`] and [`Index`].
|
||
///
|
||
/// [`str`]: primitive.str.html
|
||
/// [`Index`]: ops/trait.Index.html
|
||
///
|
||
/// This new slice goes from `begin` to `end`, including `begin` but
|
||
/// excluding `end`.
|
||
///
|
||
/// To get a mutable string slice instead, see the
|
||
/// [`slice_mut_unchecked`] method.
|
||
///
|
||
/// [`slice_mut_unchecked`]: #method.slice_mut_unchecked
|
||
///
|
||
/// # Safety
|
||
///
|
||
/// Callers of this function are responsible that three preconditions are
|
||
/// satisfied:
|
||
///
|
||
/// * `begin` must come before `end`.
|
||
/// * `begin` and `end` must be byte positions within the string slice.
|
||
/// * `begin` and `end` must lie on UTF-8 sequence boundaries.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// let s = "Löwe 老虎 Léopard";
|
||
///
|
||
/// unsafe {
|
||
/// assert_eq!("Löwe 老虎 Léopard", s.slice_unchecked(0, 21));
|
||
/// }
|
||
///
|
||
/// let s = "Hello, world!";
|
||
///
|
||
/// unsafe {
|
||
/// assert_eq!("world", s.slice_unchecked(7, 12));
|
||
/// }
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[rustc_deprecated(since = "1.29.0", reason = "use `get_unchecked(begin..end)` instead")]
|
||
#[inline]
|
||
pub unsafe fn slice_unchecked(&self, begin: usize, end: usize) -> &str {
|
||
(begin..end).get_unchecked(self)
|
||
}
|
||
|
||
/// Creates a string slice from another string slice, bypassing safety
|
||
/// checks.
|
||
/// This is generally not recommended, use with caution! For a safe
|
||
/// alternative see [`str`] and [`IndexMut`].
|
||
///
|
||
/// [`str`]: primitive.str.html
|
||
/// [`IndexMut`]: ops/trait.IndexMut.html
|
||
///
|
||
/// This new slice goes from `begin` to `end`, including `begin` but
|
||
/// excluding `end`.
|
||
///
|
||
/// To get an immutable string slice instead, see the
|
||
/// [`slice_unchecked`] method.
|
||
///
|
||
/// [`slice_unchecked`]: #method.slice_unchecked
|
||
///
|
||
/// # Safety
|
||
///
|
||
/// Callers of this function are responsible that three preconditions are
|
||
/// satisfied:
|
||
///
|
||
/// * `begin` must come before `end`.
|
||
/// * `begin` and `end` must be byte positions within the string slice.
|
||
/// * `begin` and `end` must lie on UTF-8 sequence boundaries.
|
||
#[stable(feature = "str_slice_mut", since = "1.5.0")]
|
||
#[rustc_deprecated(since = "1.29.0", reason = "use `get_unchecked_mut(begin..end)` instead")]
|
||
#[inline]
|
||
pub unsafe fn slice_mut_unchecked(&mut self, begin: usize, end: usize) -> &mut str {
|
||
(begin..end).get_unchecked_mut(self)
|
||
}
|
||
|
||
/// Divide one string slice into two at an index.
|
||
///
|
||
/// The argument, `mid`, should be a byte offset from the start of the
|
||
/// string. It must also be on the boundary of a UTF-8 code point.
|
||
///
|
||
/// The two slices returned go from the start of the string slice to `mid`,
|
||
/// and from `mid` to the end of the string slice.
|
||
///
|
||
/// To get mutable string slices instead, see the [`split_at_mut`]
|
||
/// method.
|
||
///
|
||
/// [`split_at_mut`]: #method.split_at_mut
|
||
///
|
||
/// # Panics
|
||
///
|
||
/// Panics if `mid` is not on a UTF-8 code point boundary, or if it is
|
||
/// beyond the last code point of the string slice.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// let s = "Per Martin-Löf";
|
||
///
|
||
/// let (first, last) = s.split_at(3);
|
||
///
|
||
/// assert_eq!("Per", first);
|
||
/// assert_eq!(" Martin-Löf", last);
|
||
/// ```
|
||
#[inline]
|
||
#[stable(feature = "str_split_at", since = "1.4.0")]
|
||
pub fn split_at(&self, mid: usize) -> (&str, &str) {
|
||
// is_char_boundary checks that the index is in [0, .len()]
|
||
if self.is_char_boundary(mid) {
|
||
// SAFETY: just checked that `mid` is on a char boundary.
|
||
unsafe { (self.get_unchecked(0..mid), self.get_unchecked(mid..self.len())) }
|
||
} else {
|
||
slice_error_fail(self, 0, mid)
|
||
}
|
||
}
|
||
|
||
/// Divide one mutable string slice into two at an index.
|
||
///
|
||
/// The argument, `mid`, should be a byte offset from the start of the
|
||
/// string. It must also be on the boundary of a UTF-8 code point.
|
||
///
|
||
/// The two slices returned go from the start of the string slice to `mid`,
|
||
/// and from `mid` to the end of the string slice.
|
||
///
|
||
/// To get immutable string slices instead, see the [`split_at`] method.
|
||
///
|
||
/// [`split_at`]: #method.split_at
|
||
///
|
||
/// # Panics
|
||
///
|
||
/// Panics if `mid` is not on a UTF-8 code point boundary, or if it is
|
||
/// beyond the last code point of the string slice.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// let mut s = "Per Martin-Löf".to_string();
|
||
/// {
|
||
/// let (first, last) = s.split_at_mut(3);
|
||
/// first.make_ascii_uppercase();
|
||
/// assert_eq!("PER", first);
|
||
/// assert_eq!(" Martin-Löf", last);
|
||
/// }
|
||
/// assert_eq!("PER Martin-Löf", s);
|
||
/// ```
|
||
#[inline]
|
||
#[stable(feature = "str_split_at", since = "1.4.0")]
|
||
pub fn split_at_mut(&mut self, mid: usize) -> (&mut str, &mut str) {
|
||
// is_char_boundary checks that the index is in [0, .len()]
|
||
if self.is_char_boundary(mid) {
|
||
let len = self.len();
|
||
let ptr = self.as_mut_ptr();
|
||
// SAFETY: just checked that `mid` is on a char boundary.
|
||
unsafe {
|
||
(
|
||
from_utf8_unchecked_mut(slice::from_raw_parts_mut(ptr, mid)),
|
||
from_utf8_unchecked_mut(slice::from_raw_parts_mut(ptr.add(mid), len - mid)),
|
||
)
|
||
}
|
||
} else {
|
||
slice_error_fail(self, 0, mid)
|
||
}
|
||
}
|
||
|
||
/// Returns an iterator over the [`char`]s of a string slice.
|
||
///
|
||
/// As a string slice consists of valid UTF-8, we can iterate through a
|
||
/// string slice by [`char`]. This method returns such an iterator.
|
||
///
|
||
/// It's important to remember that [`char`] represents a Unicode Scalar
|
||
/// Value, and may not match your idea of what a 'character' is. Iteration
|
||
/// over grapheme clusters may be what you actually want. This functionality
|
||
/// is not provided by Rust's standard library, check crates.io instead.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// let word = "goodbye";
|
||
///
|
||
/// let count = word.chars().count();
|
||
/// assert_eq!(7, count);
|
||
///
|
||
/// let mut chars = word.chars();
|
||
///
|
||
/// assert_eq!(Some('g'), chars.next());
|
||
/// assert_eq!(Some('o'), chars.next());
|
||
/// assert_eq!(Some('o'), chars.next());
|
||
/// assert_eq!(Some('d'), chars.next());
|
||
/// assert_eq!(Some('b'), chars.next());
|
||
/// assert_eq!(Some('y'), chars.next());
|
||
/// assert_eq!(Some('e'), chars.next());
|
||
///
|
||
/// assert_eq!(None, chars.next());
|
||
/// ```
|
||
///
|
||
/// Remember, [`char`]s may not match your human intuition about characters:
|
||
///
|
||
/// ```
|
||
/// let y = "y̆";
|
||
///
|
||
/// let mut chars = y.chars();
|
||
///
|
||
/// assert_eq!(Some('y'), chars.next()); // not 'y̆'
|
||
/// assert_eq!(Some('\u{0306}'), chars.next());
|
||
///
|
||
/// assert_eq!(None, chars.next());
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[inline]
|
||
pub fn chars(&self) -> Chars<'_> {
|
||
Chars { iter: self.as_bytes().iter() }
|
||
}
|
||
|
||
/// Returns an iterator over the [`char`]s of a string slice, and their
|
||
/// positions.
|
||
///
|
||
/// As a string slice consists of valid UTF-8, we can iterate through a
|
||
/// string slice by [`char`]. This method returns an iterator of both
|
||
/// these [`char`]s, as well as their byte positions.
|
||
///
|
||
/// The iterator yields tuples. The position is first, the [`char`] is
|
||
/// second.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// let word = "goodbye";
|
||
///
|
||
/// let count = word.char_indices().count();
|
||
/// assert_eq!(7, count);
|
||
///
|
||
/// let mut char_indices = word.char_indices();
|
||
///
|
||
/// assert_eq!(Some((0, 'g')), char_indices.next());
|
||
/// assert_eq!(Some((1, 'o')), char_indices.next());
|
||
/// assert_eq!(Some((2, 'o')), char_indices.next());
|
||
/// assert_eq!(Some((3, 'd')), char_indices.next());
|
||
/// assert_eq!(Some((4, 'b')), char_indices.next());
|
||
/// assert_eq!(Some((5, 'y')), char_indices.next());
|
||
/// assert_eq!(Some((6, 'e')), char_indices.next());
|
||
///
|
||
/// assert_eq!(None, char_indices.next());
|
||
/// ```
|
||
///
|
||
/// Remember, [`char`]s may not match your human intuition about characters:
|
||
///
|
||
/// ```
|
||
/// let yes = "y̆es";
|
||
///
|
||
/// let mut char_indices = yes.char_indices();
|
||
///
|
||
/// assert_eq!(Some((0, 'y')), char_indices.next()); // not (0, 'y̆')
|
||
/// assert_eq!(Some((1, '\u{0306}')), char_indices.next());
|
||
///
|
||
/// // note the 3 here - the last character took up two bytes
|
||
/// assert_eq!(Some((3, 'e')), char_indices.next());
|
||
/// assert_eq!(Some((4, 's')), char_indices.next());
|
||
///
|
||
/// assert_eq!(None, char_indices.next());
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[inline]
|
||
pub fn char_indices(&self) -> CharIndices<'_> {
|
||
CharIndices { front_offset: 0, iter: self.chars() }
|
||
}
|
||
|
||
/// An iterator over the bytes of a string slice.
|
||
///
|
||
/// As a string slice consists of a sequence of bytes, we can iterate
|
||
/// through a string slice by byte. This method returns such an iterator.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// let mut bytes = "bors".bytes();
|
||
///
|
||
/// assert_eq!(Some(b'b'), bytes.next());
|
||
/// assert_eq!(Some(b'o'), bytes.next());
|
||
/// assert_eq!(Some(b'r'), bytes.next());
|
||
/// assert_eq!(Some(b's'), bytes.next());
|
||
///
|
||
/// assert_eq!(None, bytes.next());
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[inline]
|
||
pub fn bytes(&self) -> Bytes<'_> {
|
||
Bytes(self.as_bytes().iter().copied())
|
||
}
|
||
|
||
/// Splits a string slice by whitespace.
|
||
///
|
||
/// The iterator returned will return string slices that are sub-slices of
|
||
/// the original string slice, separated by any amount of whitespace.
|
||
///
|
||
/// 'Whitespace' is defined according to the terms of the Unicode Derived
|
||
/// Core Property `White_Space`. If you only want to split on ASCII whitespace
|
||
/// instead, use [`split_ascii_whitespace`].
|
||
///
|
||
/// [`split_ascii_whitespace`]: #method.split_ascii_whitespace
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// let mut iter = "A few words".split_whitespace();
|
||
///
|
||
/// assert_eq!(Some("A"), iter.next());
|
||
/// assert_eq!(Some("few"), iter.next());
|
||
/// assert_eq!(Some("words"), iter.next());
|
||
///
|
||
/// assert_eq!(None, iter.next());
|
||
/// ```
|
||
///
|
||
/// All kinds of whitespace are considered:
|
||
///
|
||
/// ```
|
||
/// let mut iter = " Mary had\ta\u{2009}little \n\t lamb".split_whitespace();
|
||
/// assert_eq!(Some("Mary"), iter.next());
|
||
/// assert_eq!(Some("had"), iter.next());
|
||
/// assert_eq!(Some("a"), iter.next());
|
||
/// assert_eq!(Some("little"), iter.next());
|
||
/// assert_eq!(Some("lamb"), iter.next());
|
||
///
|
||
/// assert_eq!(None, iter.next());
|
||
/// ```
|
||
#[stable(feature = "split_whitespace", since = "1.1.0")]
|
||
#[inline]
|
||
pub fn split_whitespace(&self) -> SplitWhitespace<'_> {
|
||
SplitWhitespace { inner: self.split(IsWhitespace).filter(IsNotEmpty) }
|
||
}
|
||
|
||
/// Splits a string slice by ASCII whitespace.
|
||
///
|
||
/// The iterator returned will return string slices that are sub-slices of
|
||
/// the original string slice, separated by any amount of ASCII whitespace.
|
||
///
|
||
/// To split by Unicode `Whitespace` instead, use [`split_whitespace`].
|
||
///
|
||
/// [`split_whitespace`]: #method.split_whitespace
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// let mut iter = "A few words".split_ascii_whitespace();
|
||
///
|
||
/// assert_eq!(Some("A"), iter.next());
|
||
/// assert_eq!(Some("few"), iter.next());
|
||
/// assert_eq!(Some("words"), iter.next());
|
||
///
|
||
/// assert_eq!(None, iter.next());
|
||
/// ```
|
||
///
|
||
/// All kinds of ASCII whitespace are considered:
|
||
///
|
||
/// ```
|
||
/// let mut iter = " Mary had\ta little \n\t lamb".split_ascii_whitespace();
|
||
/// assert_eq!(Some("Mary"), iter.next());
|
||
/// assert_eq!(Some("had"), iter.next());
|
||
/// assert_eq!(Some("a"), iter.next());
|
||
/// assert_eq!(Some("little"), iter.next());
|
||
/// assert_eq!(Some("lamb"), iter.next());
|
||
///
|
||
/// assert_eq!(None, iter.next());
|
||
/// ```
|
||
#[stable(feature = "split_ascii_whitespace", since = "1.34.0")]
|
||
#[inline]
|
||
pub fn split_ascii_whitespace(&self) -> SplitAsciiWhitespace<'_> {
|
||
let inner =
|
||
self.as_bytes().split(IsAsciiWhitespace).filter(BytesIsNotEmpty).map(UnsafeBytesToStr);
|
||
SplitAsciiWhitespace { inner }
|
||
}
|
||
|
||
/// An iterator over the lines of a string, as string slices.
|
||
///
|
||
/// Lines are ended with either a newline (`\n`) or a carriage return with
|
||
/// a line feed (`\r\n`).
|
||
///
|
||
/// The final line ending is optional.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// let text = "foo\r\nbar\n\nbaz\n";
|
||
/// let mut lines = text.lines();
|
||
///
|
||
/// assert_eq!(Some("foo"), lines.next());
|
||
/// assert_eq!(Some("bar"), lines.next());
|
||
/// assert_eq!(Some(""), lines.next());
|
||
/// assert_eq!(Some("baz"), lines.next());
|
||
///
|
||
/// assert_eq!(None, lines.next());
|
||
/// ```
|
||
///
|
||
/// The final line ending isn't required:
|
||
///
|
||
/// ```
|
||
/// let text = "foo\nbar\n\r\nbaz";
|
||
/// let mut lines = text.lines();
|
||
///
|
||
/// assert_eq!(Some("foo"), lines.next());
|
||
/// assert_eq!(Some("bar"), lines.next());
|
||
/// assert_eq!(Some(""), lines.next());
|
||
/// assert_eq!(Some("baz"), lines.next());
|
||
///
|
||
/// assert_eq!(None, lines.next());
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[inline]
|
||
pub fn lines(&self) -> Lines<'_> {
|
||
Lines(self.split_terminator('\n').map(LinesAnyMap))
|
||
}
|
||
|
||
/// An iterator over the lines of a string.
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[rustc_deprecated(since = "1.4.0", reason = "use lines() instead now")]
|
||
#[inline]
|
||
#[allow(deprecated)]
|
||
pub fn lines_any(&self) -> LinesAny<'_> {
|
||
LinesAny(self.lines())
|
||
}
|
||
|
||
/// Returns an iterator of `u16` over the string encoded as UTF-16.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// let text = "Zażółć gęślą jaźń";
|
||
///
|
||
/// let utf8_len = text.len();
|
||
/// let utf16_len = text.encode_utf16().count();
|
||
///
|
||
/// assert!(utf16_len <= utf8_len);
|
||
/// ```
|
||
#[stable(feature = "encode_utf16", since = "1.8.0")]
|
||
pub fn encode_utf16(&self) -> EncodeUtf16<'_> {
|
||
EncodeUtf16 { chars: self.chars(), extra: 0 }
|
||
}
|
||
|
||
/// Returns `true` if the given pattern matches a sub-slice of
|
||
/// this string slice.
|
||
///
|
||
/// Returns `false` if it does not.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// let bananas = "bananas";
|
||
///
|
||
/// assert!(bananas.contains("nana"));
|
||
/// assert!(!bananas.contains("apples"));
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[inline]
|
||
pub fn contains<'a, P: Pattern<'a>>(&'a self, pat: P) -> bool {
|
||
pat.is_contained_in(self)
|
||
}
|
||
|
||
/// Returns `true` if the given pattern matches a prefix of this
|
||
/// string slice.
|
||
///
|
||
/// Returns `false` if it does not.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// let bananas = "bananas";
|
||
///
|
||
/// assert!(bananas.starts_with("bana"));
|
||
/// assert!(!bananas.starts_with("nana"));
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub fn starts_with<'a, P: Pattern<'a>>(&'a self, pat: P) -> bool {
|
||
pat.is_prefix_of(self)
|
||
}
|
||
|
||
/// Returns `true` if the given pattern matches a suffix of this
|
||
/// string slice.
|
||
///
|
||
/// Returns `false` if it does not.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// let bananas = "bananas";
|
||
///
|
||
/// assert!(bananas.ends_with("anas"));
|
||
/// assert!(!bananas.ends_with("nana"));
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub fn ends_with<'a, P>(&'a self, pat: P) -> bool
|
||
where
|
||
P: Pattern<'a, Searcher: ReverseSearcher<'a>>,
|
||
{
|
||
pat.is_suffix_of(self)
|
||
}
|
||
|
||
/// Returns the byte index of the first character of this string slice that
|
||
/// matches the pattern.
|
||
///
|
||
/// Returns [`None`] if the pattern doesn't match.
|
||
///
|
||
/// The pattern can be a `&str`, [`char`], or a closure that determines if
|
||
/// a character matches.
|
||
///
|
||
/// [`None`]: option/enum.Option.html#variant.None
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Simple patterns:
|
||
///
|
||
/// ```
|
||
/// let s = "Löwe 老虎 Léopard";
|
||
///
|
||
/// assert_eq!(s.find('L'), Some(0));
|
||
/// assert_eq!(s.find('é'), Some(14));
|
||
/// assert_eq!(s.find("Léopard"), Some(13));
|
||
/// ```
|
||
///
|
||
/// More complex patterns using point-free style and closures:
|
||
///
|
||
/// ```
|
||
/// let s = "Löwe 老虎 Léopard";
|
||
///
|
||
/// assert_eq!(s.find(char::is_whitespace), Some(5));
|
||
/// assert_eq!(s.find(char::is_lowercase), Some(1));
|
||
/// assert_eq!(s.find(|c: char| c.is_whitespace() || c.is_lowercase()), Some(1));
|
||
/// assert_eq!(s.find(|c: char| (c < 'o') && (c > 'a')), Some(4));
|
||
/// ```
|
||
///
|
||
/// Not finding the pattern:
|
||
///
|
||
/// ```
|
||
/// let s = "Löwe 老虎 Léopard";
|
||
/// let x: &[_] = &['1', '2'];
|
||
///
|
||
/// assert_eq!(s.find(x), None);
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[inline]
|
||
pub fn find<'a, P: Pattern<'a>>(&'a self, pat: P) -> Option<usize> {
|
||
pat.into_searcher(self).next_match().map(|(i, _)| i)
|
||
}
|
||
|
||
/// Returns the byte index of the last character of this string slice that
|
||
/// matches the pattern.
|
||
///
|
||
/// Returns [`None`] if the pattern doesn't match.
|
||
///
|
||
/// The pattern can be a `&str`, [`char`], or a closure that determines if
|
||
/// a character matches.
|
||
///
|
||
/// [`None`]: option/enum.Option.html#variant.None
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Simple patterns:
|
||
///
|
||
/// ```
|
||
/// let s = "Löwe 老虎 Léopard";
|
||
///
|
||
/// assert_eq!(s.rfind('L'), Some(13));
|
||
/// assert_eq!(s.rfind('é'), Some(14));
|
||
/// ```
|
||
///
|
||
/// More complex patterns with closures:
|
||
///
|
||
/// ```
|
||
/// let s = "Löwe 老虎 Léopard";
|
||
///
|
||
/// assert_eq!(s.rfind(char::is_whitespace), Some(12));
|
||
/// assert_eq!(s.rfind(char::is_lowercase), Some(20));
|
||
/// ```
|
||
///
|
||
/// Not finding the pattern:
|
||
///
|
||
/// ```
|
||
/// let s = "Löwe 老虎 Léopard";
|
||
/// let x: &[_] = &['1', '2'];
|
||
///
|
||
/// assert_eq!(s.rfind(x), None);
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[inline]
|
||
pub fn rfind<'a, P>(&'a self, pat: P) -> Option<usize>
|
||
where
|
||
P: Pattern<'a, Searcher: ReverseSearcher<'a>>,
|
||
{
|
||
pat.into_searcher(self).next_match_back().map(|(i, _)| i)
|
||
}
|
||
|
||
/// An iterator over substrings of this string slice, separated by
|
||
/// characters matched by a pattern.
|
||
///
|
||
/// The pattern can be any type that implements the Pattern trait. Notable
|
||
/// examples are `&str`, [`char`], and closures that determines the split.
|
||
///
|
||
/// # Iterator behavior
|
||
///
|
||
/// The returned iterator will be a [`DoubleEndedIterator`] if the pattern
|
||
/// allows a reverse search and forward/reverse search yields the same
|
||
/// elements. This is true for, e.g., [`char`], but not for `&str`.
|
||
///
|
||
/// [`DoubleEndedIterator`]: iter/trait.DoubleEndedIterator.html
|
||
///
|
||
/// If the pattern allows a reverse search but its results might differ
|
||
/// from a forward search, the [`rsplit`] method can be used.
|
||
///
|
||
/// [`rsplit`]: #method.rsplit
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Simple patterns:
|
||
///
|
||
/// ```
|
||
/// let v: Vec<&str> = "Mary had a little lamb".split(' ').collect();
|
||
/// assert_eq!(v, ["Mary", "had", "a", "little", "lamb"]);
|
||
///
|
||
/// let v: Vec<&str> = "".split('X').collect();
|
||
/// assert_eq!(v, [""]);
|
||
///
|
||
/// let v: Vec<&str> = "lionXXtigerXleopard".split('X').collect();
|
||
/// assert_eq!(v, ["lion", "", "tiger", "leopard"]);
|
||
///
|
||
/// let v: Vec<&str> = "lion::tiger::leopard".split("::").collect();
|
||
/// assert_eq!(v, ["lion", "tiger", "leopard"]);
|
||
///
|
||
/// let v: Vec<&str> = "abc1def2ghi".split(char::is_numeric).collect();
|
||
/// assert_eq!(v, ["abc", "def", "ghi"]);
|
||
///
|
||
/// let v: Vec<&str> = "lionXtigerXleopard".split(char::is_uppercase).collect();
|
||
/// assert_eq!(v, ["lion", "tiger", "leopard"]);
|
||
/// ```
|
||
///
|
||
/// A more complex pattern, using a closure:
|
||
///
|
||
/// ```
|
||
/// let v: Vec<&str> = "abc1defXghi".split(|c| c == '1' || c == 'X').collect();
|
||
/// assert_eq!(v, ["abc", "def", "ghi"]);
|
||
/// ```
|
||
///
|
||
/// If a string contains multiple contiguous separators, you will end up
|
||
/// with empty strings in the output:
|
||
///
|
||
/// ```
|
||
/// let x = "||||a||b|c".to_string();
|
||
/// let d: Vec<_> = x.split('|').collect();
|
||
///
|
||
/// assert_eq!(d, &["", "", "", "", "a", "", "b", "c"]);
|
||
/// ```
|
||
///
|
||
/// Contiguous separators are separated by the empty string.
|
||
///
|
||
/// ```
|
||
/// let x = "(///)".to_string();
|
||
/// let d: Vec<_> = x.split('/').collect();
|
||
///
|
||
/// assert_eq!(d, &["(", "", "", ")"]);
|
||
/// ```
|
||
///
|
||
/// Separators at the start or end of a string are neighbored
|
||
/// by empty strings.
|
||
///
|
||
/// ```
|
||
/// let d: Vec<_> = "010".split("0").collect();
|
||
/// assert_eq!(d, &["", "1", ""]);
|
||
/// ```
|
||
///
|
||
/// When the empty string is used as a separator, it separates
|
||
/// every character in the string, along with the beginning
|
||
/// and end of the string.
|
||
///
|
||
/// ```
|
||
/// let f: Vec<_> = "rust".split("").collect();
|
||
/// assert_eq!(f, &["", "r", "u", "s", "t", ""]);
|
||
/// ```
|
||
///
|
||
/// Contiguous separators can lead to possibly surprising behavior
|
||
/// when whitespace is used as the separator. This code is correct:
|
||
///
|
||
/// ```
|
||
/// let x = " a b c".to_string();
|
||
/// let d: Vec<_> = x.split(' ').collect();
|
||
///
|
||
/// assert_eq!(d, &["", "", "", "", "a", "", "b", "c"]);
|
||
/// ```
|
||
///
|
||
/// It does _not_ give you:
|
||
///
|
||
/// ```,ignore
|
||
/// assert_eq!(d, &["a", "b", "c"]);
|
||
/// ```
|
||
///
|
||
/// Use [`split_whitespace`] for this behavior.
|
||
///
|
||
/// [`split_whitespace`]: #method.split_whitespace
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[inline]
|
||
pub fn split<'a, P: Pattern<'a>>(&'a self, pat: P) -> Split<'a, P> {
|
||
Split(SplitInternal {
|
||
start: 0,
|
||
end: self.len(),
|
||
matcher: pat.into_searcher(self),
|
||
allow_trailing_empty: true,
|
||
finished: false,
|
||
})
|
||
}
|
||
|
||
/// An iterator over substrings of this string slice, separated by
|
||
/// characters matched by a pattern. Differs from the iterator produced by
|
||
/// `split` in that `split_inclusive` leaves the matched part as the
|
||
/// terminator of the substring.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// #![feature(split_inclusive)]
|
||
/// let v: Vec<&str> = "Mary had a little lamb\nlittle lamb\nlittle lamb."
|
||
/// .split_inclusive('\n').collect();
|
||
/// assert_eq!(v, ["Mary had a little lamb\n", "little lamb\n", "little lamb."]);
|
||
/// ```
|
||
///
|
||
/// If the last element of the string is matched,
|
||
/// that element will be considered the terminator of the preceding substring.
|
||
/// That substring will be the last item returned by the iterator.
|
||
///
|
||
/// ```
|
||
/// #![feature(split_inclusive)]
|
||
/// let v: Vec<&str> = "Mary had a little lamb\nlittle lamb\nlittle lamb.\n"
|
||
/// .split_inclusive('\n').collect();
|
||
/// assert_eq!(v, ["Mary had a little lamb\n", "little lamb\n", "little lamb.\n"]);
|
||
/// ```
|
||
#[unstable(feature = "split_inclusive", issue = "none")]
|
||
#[inline]
|
||
pub fn split_inclusive<'a, P: Pattern<'a>>(&'a self, pat: P) -> SplitInclusive<'a, P> {
|
||
SplitInclusive(SplitInternal {
|
||
start: 0,
|
||
end: self.len(),
|
||
matcher: pat.into_searcher(self),
|
||
allow_trailing_empty: false,
|
||
finished: false,
|
||
})
|
||
}
|
||
|
||
/// An iterator over substrings of the given string slice, separated by
|
||
/// characters matched by a pattern and yielded in reverse order.
|
||
///
|
||
/// The pattern can be any type that implements the Pattern trait. Notable
|
||
/// examples are `&str`, [`char`], and closures that determines the split.
|
||
///
|
||
/// # Iterator behavior
|
||
///
|
||
/// The returned iterator requires that the pattern supports a reverse
|
||
/// search, and it will be a [`DoubleEndedIterator`] if a forward/reverse
|
||
/// search yields the same elements.
|
||
///
|
||
/// [`DoubleEndedIterator`]: iter/trait.DoubleEndedIterator.html
|
||
///
|
||
/// For iterating from the front, the [`split`] method can be used.
|
||
///
|
||
/// [`split`]: #method.split
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Simple patterns:
|
||
///
|
||
/// ```
|
||
/// let v: Vec<&str> = "Mary had a little lamb".rsplit(' ').collect();
|
||
/// assert_eq!(v, ["lamb", "little", "a", "had", "Mary"]);
|
||
///
|
||
/// let v: Vec<&str> = "".rsplit('X').collect();
|
||
/// assert_eq!(v, [""]);
|
||
///
|
||
/// let v: Vec<&str> = "lionXXtigerXleopard".rsplit('X').collect();
|
||
/// assert_eq!(v, ["leopard", "tiger", "", "lion"]);
|
||
///
|
||
/// let v: Vec<&str> = "lion::tiger::leopard".rsplit("::").collect();
|
||
/// assert_eq!(v, ["leopard", "tiger", "lion"]);
|
||
/// ```
|
||
///
|
||
/// A more complex pattern, using a closure:
|
||
///
|
||
/// ```
|
||
/// let v: Vec<&str> = "abc1defXghi".rsplit(|c| c == '1' || c == 'X').collect();
|
||
/// assert_eq!(v, ["ghi", "def", "abc"]);
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[inline]
|
||
pub fn rsplit<'a, P>(&'a self, pat: P) -> RSplit<'a, P>
|
||
where
|
||
P: Pattern<'a, Searcher: ReverseSearcher<'a>>,
|
||
{
|
||
RSplit(self.split(pat).0)
|
||
}
|
||
|
||
/// An iterator over substrings of the given string slice, separated by
|
||
/// characters matched by a pattern.
|
||
///
|
||
/// The pattern can be any type that implements the Pattern trait. Notable
|
||
/// examples are `&str`, [`char`], and closures that determines the split.
|
||
///
|
||
/// Equivalent to [`split`], except that the trailing substring
|
||
/// is skipped if empty.
|
||
///
|
||
/// [`split`]: #method.split
|
||
///
|
||
/// This method can be used for string data that is _terminated_,
|
||
/// rather than _separated_ by a pattern.
|
||
///
|
||
/// # Iterator behavior
|
||
///
|
||
/// The returned iterator will be a [`DoubleEndedIterator`] if the pattern
|
||
/// allows a reverse search and forward/reverse search yields the same
|
||
/// elements. This is true for, e.g., [`char`], but not for `&str`.
|
||
///
|
||
/// [`DoubleEndedIterator`]: iter/trait.DoubleEndedIterator.html
|
||
///
|
||
/// If the pattern allows a reverse search but its results might differ
|
||
/// from a forward search, the [`rsplit_terminator`] method can be used.
|
||
///
|
||
/// [`rsplit_terminator`]: #method.rsplit_terminator
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// let v: Vec<&str> = "A.B.".split_terminator('.').collect();
|
||
/// assert_eq!(v, ["A", "B"]);
|
||
///
|
||
/// let v: Vec<&str> = "A..B..".split_terminator(".").collect();
|
||
/// assert_eq!(v, ["A", "", "B", ""]);
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[inline]
|
||
pub fn split_terminator<'a, P: Pattern<'a>>(&'a self, pat: P) -> SplitTerminator<'a, P> {
|
||
SplitTerminator(SplitInternal { allow_trailing_empty: false, ..self.split(pat).0 })
|
||
}
|
||
|
||
/// An iterator over substrings of `self`, separated by characters
|
||
/// matched by a pattern and yielded in reverse order.
|
||
///
|
||
/// The pattern can be any type that implements the Pattern trait. Notable
|
||
/// examples are `&str`, [`char`], and closures that determines the split.
|
||
/// Additional libraries might provide more complex patterns like
|
||
/// regular expressions.
|
||
///
|
||
/// Equivalent to [`split`], except that the trailing substring is
|
||
/// skipped if empty.
|
||
///
|
||
/// [`split`]: #method.split
|
||
///
|
||
/// This method can be used for string data that is _terminated_,
|
||
/// rather than _separated_ by a pattern.
|
||
///
|
||
/// # Iterator behavior
|
||
///
|
||
/// The returned iterator requires that the pattern supports a
|
||
/// reverse search, and it will be double ended if a forward/reverse
|
||
/// search yields the same elements.
|
||
///
|
||
/// For iterating from the front, the [`split_terminator`] method can be
|
||
/// used.
|
||
///
|
||
/// [`split_terminator`]: #method.split_terminator
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// let v: Vec<&str> = "A.B.".rsplit_terminator('.').collect();
|
||
/// assert_eq!(v, ["B", "A"]);
|
||
///
|
||
/// let v: Vec<&str> = "A..B..".rsplit_terminator(".").collect();
|
||
/// assert_eq!(v, ["", "B", "", "A"]);
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[inline]
|
||
pub fn rsplit_terminator<'a, P>(&'a self, pat: P) -> RSplitTerminator<'a, P>
|
||
where
|
||
P: Pattern<'a, Searcher: ReverseSearcher<'a>>,
|
||
{
|
||
RSplitTerminator(self.split_terminator(pat).0)
|
||
}
|
||
|
||
/// An iterator over substrings of the given string slice, separated by a
|
||
/// pattern, restricted to returning at most `n` items.
|
||
///
|
||
/// If `n` substrings are returned, the last substring (the `n`th substring)
|
||
/// will contain the remainder of the string.
|
||
///
|
||
/// The pattern can be any type that implements the Pattern trait. Notable
|
||
/// examples are `&str`, [`char`], and closures that determines the split.
|
||
///
|
||
/// # Iterator behavior
|
||
///
|
||
/// The returned iterator will not be double ended, because it is
|
||
/// not efficient to support.
|
||
///
|
||
/// If the pattern allows a reverse search, the [`rsplitn`] method can be
|
||
/// used.
|
||
///
|
||
/// [`rsplitn`]: #method.rsplitn
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Simple patterns:
|
||
///
|
||
/// ```
|
||
/// let v: Vec<&str> = "Mary had a little lambda".splitn(3, ' ').collect();
|
||
/// assert_eq!(v, ["Mary", "had", "a little lambda"]);
|
||
///
|
||
/// let v: Vec<&str> = "lionXXtigerXleopard".splitn(3, "X").collect();
|
||
/// assert_eq!(v, ["lion", "", "tigerXleopard"]);
|
||
///
|
||
/// let v: Vec<&str> = "abcXdef".splitn(1, 'X').collect();
|
||
/// assert_eq!(v, ["abcXdef"]);
|
||
///
|
||
/// let v: Vec<&str> = "".splitn(1, 'X').collect();
|
||
/// assert_eq!(v, [""]);
|
||
/// ```
|
||
///
|
||
/// A more complex pattern, using a closure:
|
||
///
|
||
/// ```
|
||
/// let v: Vec<&str> = "abc1defXghi".splitn(2, |c| c == '1' || c == 'X').collect();
|
||
/// assert_eq!(v, ["abc", "defXghi"]);
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[inline]
|
||
pub fn splitn<'a, P: Pattern<'a>>(&'a self, n: usize, pat: P) -> SplitN<'a, P> {
|
||
SplitN(SplitNInternal { iter: self.split(pat).0, count: n })
|
||
}
|
||
|
||
/// An iterator over substrings of this string slice, separated by a
|
||
/// pattern, starting from the end of the string, restricted to returning
|
||
/// at most `n` items.
|
||
///
|
||
/// If `n` substrings are returned, the last substring (the `n`th substring)
|
||
/// will contain the remainder of the string.
|
||
///
|
||
/// The pattern can be any type that implements the Pattern trait. Notable
|
||
/// examples are `&str`, [`char`], and closures that determines the split.
|
||
///
|
||
/// # Iterator behavior
|
||
///
|
||
/// The returned iterator will not be double ended, because it is not
|
||
/// efficient to support.
|
||
///
|
||
/// For splitting from the front, the [`splitn`] method can be used.
|
||
///
|
||
/// [`splitn`]: #method.splitn
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Simple patterns:
|
||
///
|
||
/// ```
|
||
/// let v: Vec<&str> = "Mary had a little lamb".rsplitn(3, ' ').collect();
|
||
/// assert_eq!(v, ["lamb", "little", "Mary had a"]);
|
||
///
|
||
/// let v: Vec<&str> = "lionXXtigerXleopard".rsplitn(3, 'X').collect();
|
||
/// assert_eq!(v, ["leopard", "tiger", "lionX"]);
|
||
///
|
||
/// let v: Vec<&str> = "lion::tiger::leopard".rsplitn(2, "::").collect();
|
||
/// assert_eq!(v, ["leopard", "lion::tiger"]);
|
||
/// ```
|
||
///
|
||
/// A more complex pattern, using a closure:
|
||
///
|
||
/// ```
|
||
/// let v: Vec<&str> = "abc1defXghi".rsplitn(2, |c| c == '1' || c == 'X').collect();
|
||
/// assert_eq!(v, ["ghi", "abc1def"]);
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[inline]
|
||
pub fn rsplitn<'a, P>(&'a self, n: usize, pat: P) -> RSplitN<'a, P>
|
||
where
|
||
P: Pattern<'a, Searcher: ReverseSearcher<'a>>,
|
||
{
|
||
RSplitN(self.splitn(n, pat).0)
|
||
}
|
||
|
||
/// An iterator over the disjoint matches of a pattern within the given string
|
||
/// slice.
|
||
///
|
||
/// The pattern can be a `&str`, [`char`], or a closure that determines if
|
||
/// a character matches.
|
||
///
|
||
/// # Iterator behavior
|
||
///
|
||
/// The returned iterator will be a [`DoubleEndedIterator`] if the pattern
|
||
/// allows a reverse search and forward/reverse search yields the same
|
||
/// elements. This is true for, e.g., [`char`], but not for `&str`.
|
||
///
|
||
/// [`DoubleEndedIterator`]: iter/trait.DoubleEndedIterator.html
|
||
///
|
||
/// If the pattern allows a reverse search but its results might differ
|
||
/// from a forward search, the [`rmatches`] method can be used.
|
||
///
|
||
/// [`rmatches`]: #method.rmatches
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// let v: Vec<&str> = "abcXXXabcYYYabc".matches("abc").collect();
|
||
/// assert_eq!(v, ["abc", "abc", "abc"]);
|
||
///
|
||
/// let v: Vec<&str> = "1abc2abc3".matches(char::is_numeric).collect();
|
||
/// assert_eq!(v, ["1", "2", "3"]);
|
||
/// ```
|
||
#[stable(feature = "str_matches", since = "1.2.0")]
|
||
#[inline]
|
||
pub fn matches<'a, P: Pattern<'a>>(&'a self, pat: P) -> Matches<'a, P> {
|
||
Matches(MatchesInternal(pat.into_searcher(self)))
|
||
}
|
||
|
||
/// An iterator over the disjoint matches of a pattern within this string slice,
|
||
/// yielded in reverse order.
|
||
///
|
||
/// The pattern can be a `&str`, [`char`], or a closure that determines if
|
||
/// a character matches.
|
||
///
|
||
/// # Iterator behavior
|
||
///
|
||
/// The returned iterator requires that the pattern supports a reverse
|
||
/// search, and it will be a [`DoubleEndedIterator`] if a forward/reverse
|
||
/// search yields the same elements.
|
||
///
|
||
/// [`DoubleEndedIterator`]: iter/trait.DoubleEndedIterator.html
|
||
///
|
||
/// For iterating from the front, the [`matches`] method can be used.
|
||
///
|
||
/// [`matches`]: #method.matches
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// let v: Vec<&str> = "abcXXXabcYYYabc".rmatches("abc").collect();
|
||
/// assert_eq!(v, ["abc", "abc", "abc"]);
|
||
///
|
||
/// let v: Vec<&str> = "1abc2abc3".rmatches(char::is_numeric).collect();
|
||
/// assert_eq!(v, ["3", "2", "1"]);
|
||
/// ```
|
||
#[stable(feature = "str_matches", since = "1.2.0")]
|
||
#[inline]
|
||
pub fn rmatches<'a, P>(&'a self, pat: P) -> RMatches<'a, P>
|
||
where
|
||
P: Pattern<'a, Searcher: ReverseSearcher<'a>>,
|
||
{
|
||
RMatches(self.matches(pat).0)
|
||
}
|
||
|
||
/// An iterator over the disjoint matches of a pattern within this string
|
||
/// slice as well as the index that the match starts at.
|
||
///
|
||
/// For matches of `pat` within `self` that overlap, only the indices
|
||
/// corresponding to the first match are returned.
|
||
///
|
||
/// The pattern can be a `&str`, [`char`], or a closure that determines
|
||
/// if a character matches.
|
||
///
|
||
/// # Iterator behavior
|
||
///
|
||
/// The returned iterator will be a [`DoubleEndedIterator`] if the pattern
|
||
/// allows a reverse search and forward/reverse search yields the same
|
||
/// elements. This is true for, e.g., [`char`], but not for `&str`.
|
||
///
|
||
/// [`DoubleEndedIterator`]: iter/trait.DoubleEndedIterator.html
|
||
///
|
||
/// If the pattern allows a reverse search but its results might differ
|
||
/// from a forward search, the [`rmatch_indices`] method can be used.
|
||
///
|
||
/// [`rmatch_indices`]: #method.rmatch_indices
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// let v: Vec<_> = "abcXXXabcYYYabc".match_indices("abc").collect();
|
||
/// assert_eq!(v, [(0, "abc"), (6, "abc"), (12, "abc")]);
|
||
///
|
||
/// let v: Vec<_> = "1abcabc2".match_indices("abc").collect();
|
||
/// assert_eq!(v, [(1, "abc"), (4, "abc")]);
|
||
///
|
||
/// let v: Vec<_> = "ababa".match_indices("aba").collect();
|
||
/// assert_eq!(v, [(0, "aba")]); // only the first `aba`
|
||
/// ```
|
||
#[stable(feature = "str_match_indices", since = "1.5.0")]
|
||
#[inline]
|
||
pub fn match_indices<'a, P: Pattern<'a>>(&'a self, pat: P) -> MatchIndices<'a, P> {
|
||
MatchIndices(MatchIndicesInternal(pat.into_searcher(self)))
|
||
}
|
||
|
||
/// An iterator over the disjoint matches of a pattern within `self`,
|
||
/// yielded in reverse order along with the index of the match.
|
||
///
|
||
/// For matches of `pat` within `self` that overlap, only the indices
|
||
/// corresponding to the last match are returned.
|
||
///
|
||
/// The pattern can be a `&str`, [`char`], or a closure that determines if a
|
||
/// character matches.
|
||
///
|
||
/// # Iterator behavior
|
||
///
|
||
/// The returned iterator requires that the pattern supports a reverse
|
||
/// search, and it will be a [`DoubleEndedIterator`] if a forward/reverse
|
||
/// search yields the same elements.
|
||
///
|
||
/// [`DoubleEndedIterator`]: iter/trait.DoubleEndedIterator.html
|
||
///
|
||
/// For iterating from the front, the [`match_indices`] method can be used.
|
||
///
|
||
/// [`match_indices`]: #method.match_indices
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// let v: Vec<_> = "abcXXXabcYYYabc".rmatch_indices("abc").collect();
|
||
/// assert_eq!(v, [(12, "abc"), (6, "abc"), (0, "abc")]);
|
||
///
|
||
/// let v: Vec<_> = "1abcabc2".rmatch_indices("abc").collect();
|
||
/// assert_eq!(v, [(4, "abc"), (1, "abc")]);
|
||
///
|
||
/// let v: Vec<_> = "ababa".rmatch_indices("aba").collect();
|
||
/// assert_eq!(v, [(2, "aba")]); // only the last `aba`
|
||
/// ```
|
||
#[stable(feature = "str_match_indices", since = "1.5.0")]
|
||
#[inline]
|
||
pub fn rmatch_indices<'a, P>(&'a self, pat: P) -> RMatchIndices<'a, P>
|
||
where
|
||
P: Pattern<'a, Searcher: ReverseSearcher<'a>>,
|
||
{
|
||
RMatchIndices(self.match_indices(pat).0)
|
||
}
|
||
|
||
/// Returns a string slice with leading and trailing whitespace removed.
|
||
///
|
||
/// 'Whitespace' is defined according to the terms of the Unicode Derived
|
||
/// Core Property `White_Space`.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// let s = " Hello\tworld\t";
|
||
///
|
||
/// assert_eq!("Hello\tworld", s.trim());
|
||
/// ```
|
||
#[must_use = "this returns the trimmed string as a slice, \
|
||
without modifying the original"]
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub fn trim(&self) -> &str {
|
||
self.trim_matches(|c: char| c.is_whitespace())
|
||
}
|
||
|
||
/// Returns a string slice with leading whitespace removed.
|
||
///
|
||
/// 'Whitespace' is defined according to the terms of the Unicode Derived
|
||
/// Core Property `White_Space`.
|
||
///
|
||
/// # Text directionality
|
||
///
|
||
/// A string is a sequence of bytes. `start` in this context means the first
|
||
/// position of that byte string; for a left-to-right language like English or
|
||
/// Russian, this will be left side, and for right-to-left languages like
|
||
/// Arabic or Hebrew, this will be the right side.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// let s = " Hello\tworld\t";
|
||
/// assert_eq!("Hello\tworld\t", s.trim_start());
|
||
/// ```
|
||
///
|
||
/// Directionality:
|
||
///
|
||
/// ```
|
||
/// let s = " English ";
|
||
/// assert!(Some('E') == s.trim_start().chars().next());
|
||
///
|
||
/// let s = " עברית ";
|
||
/// assert!(Some('ע') == s.trim_start().chars().next());
|
||
/// ```
|
||
#[must_use = "this returns the trimmed string as a new slice, \
|
||
without modifying the original"]
|
||
#[stable(feature = "trim_direction", since = "1.30.0")]
|
||
pub fn trim_start(&self) -> &str {
|
||
self.trim_start_matches(|c: char| c.is_whitespace())
|
||
}
|
||
|
||
/// Returns a string slice with trailing whitespace removed.
|
||
///
|
||
/// 'Whitespace' is defined according to the terms of the Unicode Derived
|
||
/// Core Property `White_Space`.
|
||
///
|
||
/// # Text directionality
|
||
///
|
||
/// A string is a sequence of bytes. `end` in this context means the last
|
||
/// position of that byte string; for a left-to-right language like English or
|
||
/// Russian, this will be right side, and for right-to-left languages like
|
||
/// Arabic or Hebrew, this will be the left side.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// let s = " Hello\tworld\t";
|
||
/// assert_eq!(" Hello\tworld", s.trim_end());
|
||
/// ```
|
||
///
|
||
/// Directionality:
|
||
///
|
||
/// ```
|
||
/// let s = " English ";
|
||
/// assert!(Some('h') == s.trim_end().chars().rev().next());
|
||
///
|
||
/// let s = " עברית ";
|
||
/// assert!(Some('ת') == s.trim_end().chars().rev().next());
|
||
/// ```
|
||
#[must_use = "this returns the trimmed string as a new slice, \
|
||
without modifying the original"]
|
||
#[stable(feature = "trim_direction", since = "1.30.0")]
|
||
pub fn trim_end(&self) -> &str {
|
||
self.trim_end_matches(|c: char| c.is_whitespace())
|
||
}
|
||
|
||
/// Returns a string slice with leading whitespace removed.
|
||
///
|
||
/// 'Whitespace' is defined according to the terms of the Unicode Derived
|
||
/// Core Property `White_Space`.
|
||
///
|
||
/// # Text directionality
|
||
///
|
||
/// A string is a sequence of bytes. 'Left' in this context means the first
|
||
/// position of that byte string; for a language like Arabic or Hebrew
|
||
/// which are 'right to left' rather than 'left to right', this will be
|
||
/// the _right_ side, not the left.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// let s = " Hello\tworld\t";
|
||
///
|
||
/// assert_eq!("Hello\tworld\t", s.trim_left());
|
||
/// ```
|
||
///
|
||
/// Directionality:
|
||
///
|
||
/// ```
|
||
/// let s = " English";
|
||
/// assert!(Some('E') == s.trim_left().chars().next());
|
||
///
|
||
/// let s = " עברית";
|
||
/// assert!(Some('ע') == s.trim_left().chars().next());
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[rustc_deprecated(
|
||
since = "1.33.0",
|
||
reason = "superseded by `trim_start`",
|
||
suggestion = "trim_start"
|
||
)]
|
||
pub fn trim_left(&self) -> &str {
|
||
self.trim_start()
|
||
}
|
||
|
||
/// Returns a string slice with trailing whitespace removed.
|
||
///
|
||
/// 'Whitespace' is defined according to the terms of the Unicode Derived
|
||
/// Core Property `White_Space`.
|
||
///
|
||
/// # Text directionality
|
||
///
|
||
/// A string is a sequence of bytes. 'Right' in this context means the last
|
||
/// position of that byte string; for a language like Arabic or Hebrew
|
||
/// which are 'right to left' rather than 'left to right', this will be
|
||
/// the _left_ side, not the right.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// let s = " Hello\tworld\t";
|
||
///
|
||
/// assert_eq!(" Hello\tworld", s.trim_right());
|
||
/// ```
|
||
///
|
||
/// Directionality:
|
||
///
|
||
/// ```
|
||
/// let s = "English ";
|
||
/// assert!(Some('h') == s.trim_right().chars().rev().next());
|
||
///
|
||
/// let s = "עברית ";
|
||
/// assert!(Some('ת') == s.trim_right().chars().rev().next());
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[rustc_deprecated(
|
||
since = "1.33.0",
|
||
reason = "superseded by `trim_end`",
|
||
suggestion = "trim_end"
|
||
)]
|
||
pub fn trim_right(&self) -> &str {
|
||
self.trim_end()
|
||
}
|
||
|
||
/// Returns a string slice with all prefixes and suffixes that match a
|
||
/// pattern repeatedly removed.
|
||
///
|
||
/// The pattern can be a [`char`] or a closure that determines if a
|
||
/// character matches.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Simple patterns:
|
||
///
|
||
/// ```
|
||
/// assert_eq!("11foo1bar11".trim_matches('1'), "foo1bar");
|
||
/// assert_eq!("123foo1bar123".trim_matches(char::is_numeric), "foo1bar");
|
||
///
|
||
/// let x: &[_] = &['1', '2'];
|
||
/// assert_eq!("12foo1bar12".trim_matches(x), "foo1bar");
|
||
/// ```
|
||
///
|
||
/// A more complex pattern, using a closure:
|
||
///
|
||
/// ```
|
||
/// assert_eq!("1foo1barXX".trim_matches(|c| c == '1' || c == 'X'), "foo1bar");
|
||
/// ```
|
||
#[must_use = "this returns the trimmed string as a new slice, \
|
||
without modifying the original"]
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub fn trim_matches<'a, P>(&'a self, pat: P) -> &'a str
|
||
where
|
||
P: Pattern<'a, Searcher: DoubleEndedSearcher<'a>>,
|
||
{
|
||
let mut i = 0;
|
||
let mut j = 0;
|
||
let mut matcher = pat.into_searcher(self);
|
||
if let Some((a, b)) = matcher.next_reject() {
|
||
i = a;
|
||
j = b; // Remember earliest known match, correct it below if
|
||
// last match is different
|
||
}
|
||
if let Some((_, b)) = matcher.next_reject_back() {
|
||
j = b;
|
||
}
|
||
// SAFETY: `Searcher` is known to return valid indices.
|
||
unsafe { self.get_unchecked(i..j) }
|
||
}
|
||
|
||
/// Returns a string slice with all prefixes that match a pattern
|
||
/// repeatedly removed.
|
||
///
|
||
/// The pattern can be a `&str`, [`char`], or a closure that determines if
|
||
/// a character matches.
|
||
///
|
||
/// # Text directionality
|
||
///
|
||
/// A string is a sequence of bytes. `start` in this context means the first
|
||
/// position of that byte string; for a left-to-right language like English or
|
||
/// Russian, this will be left side, and for right-to-left languages like
|
||
/// Arabic or Hebrew, this will be the right side.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// assert_eq!("11foo1bar11".trim_start_matches('1'), "foo1bar11");
|
||
/// assert_eq!("123foo1bar123".trim_start_matches(char::is_numeric), "foo1bar123");
|
||
///
|
||
/// let x: &[_] = &['1', '2'];
|
||
/// assert_eq!("12foo1bar12".trim_start_matches(x), "foo1bar12");
|
||
/// ```
|
||
#[must_use = "this returns the trimmed string as a new slice, \
|
||
without modifying the original"]
|
||
#[stable(feature = "trim_direction", since = "1.30.0")]
|
||
pub fn trim_start_matches<'a, P: Pattern<'a>>(&'a self, pat: P) -> &'a str {
|
||
let mut i = self.len();
|
||
let mut matcher = pat.into_searcher(self);
|
||
if let Some((a, _)) = matcher.next_reject() {
|
||
i = a;
|
||
}
|
||
// SAFETY: `Searcher` is known to return valid indices.
|
||
unsafe { self.get_unchecked(i..self.len()) }
|
||
}
|
||
|
||
/// Returns a string slice with the prefix removed.
|
||
///
|
||
/// If the string starts with the pattern `prefix`, `Some` is returned with the substring where
|
||
/// the prefix is removed. Unlike `trim_start_matches`, this method removes the prefix exactly
|
||
/// once.
|
||
///
|
||
/// If the string does not start with `prefix`, `None` is returned.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// #![feature(str_strip)]
|
||
///
|
||
/// assert_eq!("foobar".strip_prefix("foo"), Some("bar"));
|
||
/// assert_eq!("foobar".strip_prefix("bar"), None);
|
||
/// assert_eq!("foofoo".strip_prefix("foo"), Some("foo"));
|
||
/// ```
|
||
#[must_use = "this returns the remaining substring as a new slice, \
|
||
without modifying the original"]
|
||
#[unstable(feature = "str_strip", reason = "newly added", issue = "67302")]
|
||
pub fn strip_prefix<'a, P: Pattern<'a>>(&'a self, prefix: P) -> Option<&'a str> {
|
||
let mut matcher = prefix.into_searcher(self);
|
||
if let SearchStep::Match(start, len) = matcher.next() {
|
||
debug_assert_eq!(
|
||
start, 0,
|
||
"The first search step from Searcher \
|
||
must include the first character"
|
||
);
|
||
// SAFETY: `Searcher` is known to return valid indices.
|
||
unsafe { Some(self.get_unchecked(len..)) }
|
||
} else {
|
||
None
|
||
}
|
||
}
|
||
|
||
/// Returns a string slice with the suffix removed.
|
||
///
|
||
/// If the string ends with the pattern `suffix`, `Some` is returned with the substring where
|
||
/// the suffix is removed. Unlike `trim_end_matches`, this method removes the suffix exactly
|
||
/// once.
|
||
///
|
||
/// If the string does not end with `suffix`, `None` is returned.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// #![feature(str_strip)]
|
||
/// assert_eq!("barfoo".strip_suffix("foo"), Some("bar"));
|
||
/// assert_eq!("barfoo".strip_suffix("bar"), None);
|
||
/// assert_eq!("foofoo".strip_suffix("foo"), Some("foo"));
|
||
/// ```
|
||
#[must_use = "this returns the remaining substring as a new slice, \
|
||
without modifying the original"]
|
||
#[unstable(feature = "str_strip", reason = "newly added", issue = "67302")]
|
||
pub fn strip_suffix<'a, P>(&'a self, suffix: P) -> Option<&'a str>
|
||
where
|
||
P: Pattern<'a>,
|
||
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>,
|
||
{
|
||
let mut matcher = suffix.into_searcher(self);
|
||
if let SearchStep::Match(start, end) = matcher.next_back() {
|
||
debug_assert_eq!(
|
||
end,
|
||
self.len(),
|
||
"The first search step from ReverseSearcher \
|
||
must include the last character"
|
||
);
|
||
// SAFETY: `Searcher` is known to return valid indices.
|
||
unsafe { Some(self.get_unchecked(..start)) }
|
||
} else {
|
||
None
|
||
}
|
||
}
|
||
|
||
/// Returns a string slice with all suffixes that match a pattern
|
||
/// repeatedly removed.
|
||
///
|
||
/// The pattern can be a `&str`, [`char`], or a closure that
|
||
/// determines if a character matches.
|
||
///
|
||
/// # Text directionality
|
||
///
|
||
/// A string is a sequence of bytes. `end` in this context means the last
|
||
/// position of that byte string; for a left-to-right language like English or
|
||
/// Russian, this will be right side, and for right-to-left languages like
|
||
/// Arabic or Hebrew, this will be the left side.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Simple patterns:
|
||
///
|
||
/// ```
|
||
/// assert_eq!("11foo1bar11".trim_end_matches('1'), "11foo1bar");
|
||
/// assert_eq!("123foo1bar123".trim_end_matches(char::is_numeric), "123foo1bar");
|
||
///
|
||
/// let x: &[_] = &['1', '2'];
|
||
/// assert_eq!("12foo1bar12".trim_end_matches(x), "12foo1bar");
|
||
/// ```
|
||
///
|
||
/// A more complex pattern, using a closure:
|
||
///
|
||
/// ```
|
||
/// assert_eq!("1fooX".trim_end_matches(|c| c == '1' || c == 'X'), "1foo");
|
||
/// ```
|
||
#[must_use = "this returns the trimmed string as a new slice, \
|
||
without modifying the original"]
|
||
#[stable(feature = "trim_direction", since = "1.30.0")]
|
||
pub fn trim_end_matches<'a, P>(&'a self, pat: P) -> &'a str
|
||
where
|
||
P: Pattern<'a, Searcher: ReverseSearcher<'a>>,
|
||
{
|
||
let mut j = 0;
|
||
let mut matcher = pat.into_searcher(self);
|
||
if let Some((_, b)) = matcher.next_reject_back() {
|
||
j = b;
|
||
}
|
||
// SAFETY: `Searcher` is known to return valid indices.
|
||
unsafe { self.get_unchecked(0..j) }
|
||
}
|
||
|
||
/// Returns a string slice with all prefixes that match a pattern
|
||
/// repeatedly removed.
|
||
///
|
||
/// The pattern can be a `&str`, [`char`], or a closure that determines if
|
||
/// a character matches.
|
||
///
|
||
/// [`char`]: primitive.char.html
|
||
///
|
||
/// # Text directionality
|
||
///
|
||
/// A string is a sequence of bytes. 'Left' in this context means the first
|
||
/// position of that byte string; for a language like Arabic or Hebrew
|
||
/// which are 'right to left' rather than 'left to right', this will be
|
||
/// the _right_ side, not the left.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage:
|
||
///
|
||
/// ```
|
||
/// assert_eq!("11foo1bar11".trim_left_matches('1'), "foo1bar11");
|
||
/// assert_eq!("123foo1bar123".trim_left_matches(char::is_numeric), "foo1bar123");
|
||
///
|
||
/// let x: &[_] = &['1', '2'];
|
||
/// assert_eq!("12foo1bar12".trim_left_matches(x), "foo1bar12");
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[rustc_deprecated(
|
||
since = "1.33.0",
|
||
reason = "superseded by `trim_start_matches`",
|
||
suggestion = "trim_start_matches"
|
||
)]
|
||
pub fn trim_left_matches<'a, P: Pattern<'a>>(&'a self, pat: P) -> &'a str {
|
||
self.trim_start_matches(pat)
|
||
}
|
||
|
||
/// Returns a string slice with all suffixes that match a pattern
|
||
/// repeatedly removed.
|
||
///
|
||
/// The pattern can be a `&str`, [`char`], or a closure that
|
||
/// determines if a character matches.
|
||
///
|
||
/// [`char`]: primitive.char.html
|
||
///
|
||
/// # Text directionality
|
||
///
|
||
/// A string is a sequence of bytes. 'Right' in this context means the last
|
||
/// position of that byte string; for a language like Arabic or Hebrew
|
||
/// which are 'right to left' rather than 'left to right', this will be
|
||
/// the _left_ side, not the right.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Simple patterns:
|
||
///
|
||
/// ```
|
||
/// assert_eq!("11foo1bar11".trim_right_matches('1'), "11foo1bar");
|
||
/// assert_eq!("123foo1bar123".trim_right_matches(char::is_numeric), "123foo1bar");
|
||
///
|
||
/// let x: &[_] = &['1', '2'];
|
||
/// assert_eq!("12foo1bar12".trim_right_matches(x), "12foo1bar");
|
||
/// ```
|
||
///
|
||
/// A more complex pattern, using a closure:
|
||
///
|
||
/// ```
|
||
/// assert_eq!("1fooX".trim_right_matches(|c| c == '1' || c == 'X'), "1foo");
|
||
/// ```
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
#[rustc_deprecated(
|
||
since = "1.33.0",
|
||
reason = "superseded by `trim_end_matches`",
|
||
suggestion = "trim_end_matches"
|
||
)]
|
||
pub fn trim_right_matches<'a, P>(&'a self, pat: P) -> &'a str
|
||
where
|
||
P: Pattern<'a, Searcher: ReverseSearcher<'a>>,
|
||
{
|
||
self.trim_end_matches(pat)
|
||
}
|
||
|
||
/// Parses this string slice into another type.
|
||
///
|
||
/// Because `parse` is so general, it can cause problems with type
|
||
/// inference. As such, `parse` is one of the few times you'll see
|
||
/// the syntax affectionately known as the 'turbofish': `::<>`. This
|
||
/// helps the inference algorithm understand specifically which type
|
||
/// you're trying to parse into.
|
||
///
|
||
/// `parse` can parse any type that implements the [`FromStr`] trait.
|
||
///
|
||
/// [`FromStr`]: str/trait.FromStr.html
|
||
///
|
||
/// # Errors
|
||
///
|
||
/// Will return [`Err`] if it's not possible to parse this string slice into
|
||
/// the desired type.
|
||
///
|
||
/// [`Err`]: str/trait.FromStr.html#associatedtype.Err
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// Basic usage
|
||
///
|
||
/// ```
|
||
/// let four: u32 = "4".parse().unwrap();
|
||
///
|
||
/// assert_eq!(4, four);
|
||
/// ```
|
||
///
|
||
/// Using the 'turbofish' instead of annotating `four`:
|
||
///
|
||
/// ```
|
||
/// let four = "4".parse::<u32>();
|
||
///
|
||
/// assert_eq!(Ok(4), four);
|
||
/// ```
|
||
///
|
||
/// Failing to parse:
|
||
///
|
||
/// ```
|
||
/// let nope = "j".parse::<u32>();
|
||
///
|
||
/// assert!(nope.is_err());
|
||
/// ```
|
||
#[inline]
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
pub fn parse<F: FromStr>(&self) -> Result<F, F::Err> {
|
||
FromStr::from_str(self)
|
||
}
|
||
|
||
/// Checks if all characters in this string are within the ASCII range.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// let ascii = "hello!\n";
|
||
/// let non_ascii = "Grüße, Jürgen ❤";
|
||
///
|
||
/// assert!(ascii.is_ascii());
|
||
/// assert!(!non_ascii.is_ascii());
|
||
/// ```
|
||
#[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
|
||
#[inline]
|
||
pub fn is_ascii(&self) -> bool {
|
||
// We can treat each byte as character here: all multibyte characters
|
||
// start with a byte that is not in the ascii range, so we will stop
|
||
// there already.
|
||
self.bytes().all(|b| b.is_ascii())
|
||
}
|
||
|
||
/// Checks that two strings are an ASCII case-insensitive match.
|
||
///
|
||
/// Same as `to_ascii_lowercase(a) == to_ascii_lowercase(b)`,
|
||
/// but without allocating and copying temporaries.
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// assert!("Ferris".eq_ignore_ascii_case("FERRIS"));
|
||
/// assert!("Ferrös".eq_ignore_ascii_case("FERRöS"));
|
||
/// assert!(!"Ferrös".eq_ignore_ascii_case("FERRÖS"));
|
||
/// ```
|
||
#[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
|
||
#[inline]
|
||
pub fn eq_ignore_ascii_case(&self, other: &str) -> bool {
|
||
self.as_bytes().eq_ignore_ascii_case(other.as_bytes())
|
||
}
|
||
|
||
/// Converts this string to its ASCII upper case equivalent in-place.
|
||
///
|
||
/// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z',
|
||
/// but non-ASCII letters are unchanged.
|
||
///
|
||
/// To return a new uppercased value without modifying the existing one, use
|
||
/// [`to_ascii_uppercase`].
|
||
///
|
||
/// [`to_ascii_uppercase`]: #method.to_ascii_uppercase
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// let mut s = String::from("Grüße, Jürgen ❤");
|
||
///
|
||
/// s.make_ascii_uppercase();
|
||
///
|
||
/// assert_eq!("GRüßE, JüRGEN ❤", s);
|
||
/// ```
|
||
#[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
|
||
pub fn make_ascii_uppercase(&mut self) {
|
||
// SAFETY: safe because we transmute two types with the same layout.
|
||
let me = unsafe { self.as_bytes_mut() };
|
||
me.make_ascii_uppercase()
|
||
}
|
||
|
||
/// Converts this string to its ASCII lower case equivalent in-place.
|
||
///
|
||
/// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z',
|
||
/// but non-ASCII letters are unchanged.
|
||
///
|
||
/// To return a new lowercased value without modifying the existing one, use
|
||
/// [`to_ascii_lowercase`].
|
||
///
|
||
/// [`to_ascii_lowercase`]: #method.to_ascii_lowercase
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// ```
|
||
/// let mut s = String::from("GRÜßE, JÜRGEN ❤");
|
||
///
|
||
/// s.make_ascii_lowercase();
|
||
///
|
||
/// assert_eq!("grÜße, jÜrgen ❤", s);
|
||
/// ```
|
||
#[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
|
||
pub fn make_ascii_lowercase(&mut self) {
|
||
// SAFETY: safe because we transmute two types with the same layout.
|
||
let me = unsafe { self.as_bytes_mut() };
|
||
me.make_ascii_lowercase()
|
||
}
|
||
|
||
/// Return an iterator that escapes each char in `self` with [`char::escape_debug`].
|
||
///
|
||
/// Note: only extended grapheme codepoints that begin the string will be
|
||
/// escaped.
|
||
///
|
||
/// [`char::escape_debug`]: ../std/primitive.char.html#method.escape_debug
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// As an iterator:
|
||
///
|
||
/// ```
|
||
/// for c in "❤\n!".escape_debug() {
|
||
/// print!("{}", c);
|
||
/// }
|
||
/// println!();
|
||
/// ```
|
||
///
|
||
/// Using `println!` directly:
|
||
///
|
||
/// ```
|
||
/// println!("{}", "❤\n!".escape_debug());
|
||
/// ```
|
||
///
|
||
///
|
||
/// Both are equivalent to:
|
||
///
|
||
/// ```
|
||
/// println!("❤\\n!");
|
||
/// ```
|
||
///
|
||
/// Using `to_string`:
|
||
///
|
||
/// ```
|
||
/// assert_eq!("❤\n!".escape_debug().to_string(), "❤\\n!");
|
||
/// ```
|
||
#[stable(feature = "str_escape", since = "1.34.0")]
|
||
pub fn escape_debug(&self) -> EscapeDebug<'_> {
|
||
let mut chars = self.chars();
|
||
EscapeDebug {
|
||
inner: chars
|
||
.next()
|
||
.map(|first| first.escape_debug_ext(true))
|
||
.into_iter()
|
||
.flatten()
|
||
.chain(chars.flat_map(CharEscapeDebugContinue)),
|
||
}
|
||
}
|
||
|
||
/// Return an iterator that escapes each char in `self` with [`char::escape_default`].
|
||
///
|
||
/// [`char::escape_default`]: ../std/primitive.char.html#method.escape_default
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// As an iterator:
|
||
///
|
||
/// ```
|
||
/// for c in "❤\n!".escape_default() {
|
||
/// print!("{}", c);
|
||
/// }
|
||
/// println!();
|
||
/// ```
|
||
///
|
||
/// Using `println!` directly:
|
||
///
|
||
/// ```
|
||
/// println!("{}", "❤\n!".escape_default());
|
||
/// ```
|
||
///
|
||
///
|
||
/// Both are equivalent to:
|
||
///
|
||
/// ```
|
||
/// println!("\\u{{2764}}\\n!");
|
||
/// ```
|
||
///
|
||
/// Using `to_string`:
|
||
///
|
||
/// ```
|
||
/// assert_eq!("❤\n!".escape_default().to_string(), "\\u{2764}\\n!");
|
||
/// ```
|
||
#[stable(feature = "str_escape", since = "1.34.0")]
|
||
pub fn escape_default(&self) -> EscapeDefault<'_> {
|
||
EscapeDefault { inner: self.chars().flat_map(CharEscapeDefault) }
|
||
}
|
||
|
||
/// Return an iterator that escapes each char in `self` with [`char::escape_unicode`].
|
||
///
|
||
/// [`char::escape_unicode`]: ../std/primitive.char.html#method.escape_unicode
|
||
///
|
||
/// # Examples
|
||
///
|
||
/// As an iterator:
|
||
///
|
||
/// ```
|
||
/// for c in "❤\n!".escape_unicode() {
|
||
/// print!("{}", c);
|
||
/// }
|
||
/// println!();
|
||
/// ```
|
||
///
|
||
/// Using `println!` directly:
|
||
///
|
||
/// ```
|
||
/// println!("{}", "❤\n!".escape_unicode());
|
||
/// ```
|
||
///
|
||
///
|
||
/// Both are equivalent to:
|
||
///
|
||
/// ```
|
||
/// println!("\\u{{2764}}\\u{{a}}\\u{{21}}");
|
||
/// ```
|
||
///
|
||
/// Using `to_string`:
|
||
///
|
||
/// ```
|
||
/// assert_eq!("❤\n!".escape_unicode().to_string(), "\\u{2764}\\u{a}\\u{21}");
|
||
/// ```
|
||
#[stable(feature = "str_escape", since = "1.34.0")]
|
||
pub fn escape_unicode(&self) -> EscapeUnicode<'_> {
|
||
EscapeUnicode { inner: self.chars().flat_map(CharEscapeUnicode) }
|
||
}
|
||
}
|
||
|
||
impl_fn_for_zst! {
|
||
#[derive(Clone)]
|
||
struct CharEscapeDebugContinue impl Fn = |c: char| -> char::EscapeDebug {
|
||
c.escape_debug_ext(false)
|
||
};
|
||
|
||
#[derive(Clone)]
|
||
struct CharEscapeUnicode impl Fn = |c: char| -> char::EscapeUnicode {
|
||
c.escape_unicode()
|
||
};
|
||
#[derive(Clone)]
|
||
struct CharEscapeDefault impl Fn = |c: char| -> char::EscapeDefault {
|
||
c.escape_default()
|
||
};
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl AsRef<[u8]> for str {
|
||
#[inline]
|
||
fn as_ref(&self) -> &[u8] {
|
||
self.as_bytes()
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "rust1", since = "1.0.0")]
|
||
impl Default for &str {
|
||
/// Creates an empty str
|
||
fn default() -> Self {
|
||
""
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "default_mut_str", since = "1.28.0")]
|
||
impl Default for &mut str {
|
||
/// Creates an empty mutable str
|
||
fn default() -> Self {
|
||
// SAFETY: The empty string is valid UTF-8.
|
||
unsafe { from_utf8_unchecked_mut(&mut []) }
|
||
}
|
||
}
|
||
|
||
/// An iterator over the non-whitespace substrings of a string,
|
||
/// separated by any amount of whitespace.
|
||
///
|
||
/// This struct is created by the [`split_whitespace`] method on [`str`].
|
||
/// See its documentation for more.
|
||
///
|
||
/// [`split_whitespace`]: ../../std/primitive.str.html#method.split_whitespace
|
||
/// [`str`]: ../../std/primitive.str.html
|
||
#[stable(feature = "split_whitespace", since = "1.1.0")]
|
||
#[derive(Clone, Debug)]
|
||
pub struct SplitWhitespace<'a> {
|
||
inner: Filter<Split<'a, IsWhitespace>, IsNotEmpty>,
|
||
}
|
||
|
||
/// An iterator over the non-ASCII-whitespace substrings of a string,
|
||
/// separated by any amount of ASCII whitespace.
|
||
///
|
||
/// This struct is created by the [`split_ascii_whitespace`] method on [`str`].
|
||
/// See its documentation for more.
|
||
///
|
||
/// [`split_ascii_whitespace`]: ../../std/primitive.str.html#method.split_ascii_whitespace
|
||
/// [`str`]: ../../std/primitive.str.html
|
||
#[stable(feature = "split_ascii_whitespace", since = "1.34.0")]
|
||
#[derive(Clone, Debug)]
|
||
pub struct SplitAsciiWhitespace<'a> {
|
||
inner: Map<Filter<SliceSplit<'a, u8, IsAsciiWhitespace>, BytesIsNotEmpty>, UnsafeBytesToStr>,
|
||
}
|
||
|
||
/// An iterator over the substrings of a string,
|
||
/// terminated by a substring matching to a predicate function
|
||
/// Unlike `Split`, it contains the matched part as a terminator
|
||
/// of the subslice.
|
||
///
|
||
/// This struct is created by the [`split_inclusive`] method on [`str`].
|
||
/// See its documentation for more.
|
||
///
|
||
/// [`split_inclusive`]: ../../std/primitive.str.html#method.split_inclusive
|
||
/// [`str`]: ../../std/primitive.str.html
|
||
#[unstable(feature = "split_inclusive", issue = "none")]
|
||
pub struct SplitInclusive<'a, P: Pattern<'a>>(SplitInternal<'a, P>);
|
||
|
||
impl_fn_for_zst! {
|
||
#[derive(Clone)]
|
||
struct IsWhitespace impl Fn = |c: char| -> bool {
|
||
c.is_whitespace()
|
||
};
|
||
|
||
#[derive(Clone)]
|
||
struct IsAsciiWhitespace impl Fn = |byte: &u8| -> bool {
|
||
byte.is_ascii_whitespace()
|
||
};
|
||
|
||
#[derive(Clone)]
|
||
struct IsNotEmpty impl<'a, 'b> Fn = |s: &'a &'b str| -> bool {
|
||
!s.is_empty()
|
||
};
|
||
|
||
#[derive(Clone)]
|
||
struct BytesIsNotEmpty impl<'a, 'b> Fn = |s: &'a &'b [u8]| -> bool {
|
||
!s.is_empty()
|
||
};
|
||
|
||
#[derive(Clone)]
|
||
struct UnsafeBytesToStr impl<'a> Fn = |bytes: &'a [u8]| -> &'a str {
|
||
// SAFETY: not safe
|
||
unsafe { from_utf8_unchecked(bytes) }
|
||
};
|
||
}
|
||
|
||
#[stable(feature = "split_whitespace", since = "1.1.0")]
|
||
impl<'a> Iterator for SplitWhitespace<'a> {
|
||
type Item = &'a str;
|
||
|
||
#[inline]
|
||
fn next(&mut self) -> Option<&'a str> {
|
||
self.inner.next()
|
||
}
|
||
|
||
#[inline]
|
||
fn size_hint(&self) -> (usize, Option<usize>) {
|
||
self.inner.size_hint()
|
||
}
|
||
|
||
#[inline]
|
||
fn last(mut self) -> Option<&'a str> {
|
||
self.next_back()
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "split_whitespace", since = "1.1.0")]
|
||
impl<'a> DoubleEndedIterator for SplitWhitespace<'a> {
|
||
#[inline]
|
||
fn next_back(&mut self) -> Option<&'a str> {
|
||
self.inner.next_back()
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "fused", since = "1.26.0")]
|
||
impl FusedIterator for SplitWhitespace<'_> {}
|
||
|
||
#[stable(feature = "split_ascii_whitespace", since = "1.34.0")]
|
||
impl<'a> Iterator for SplitAsciiWhitespace<'a> {
|
||
type Item = &'a str;
|
||
|
||
#[inline]
|
||
fn next(&mut self) -> Option<&'a str> {
|
||
self.inner.next()
|
||
}
|
||
|
||
#[inline]
|
||
fn size_hint(&self) -> (usize, Option<usize>) {
|
||
self.inner.size_hint()
|
||
}
|
||
|
||
#[inline]
|
||
fn last(mut self) -> Option<&'a str> {
|
||
self.next_back()
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "split_ascii_whitespace", since = "1.34.0")]
|
||
impl<'a> DoubleEndedIterator for SplitAsciiWhitespace<'a> {
|
||
#[inline]
|
||
fn next_back(&mut self) -> Option<&'a str> {
|
||
self.inner.next_back()
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "split_ascii_whitespace", since = "1.34.0")]
|
||
impl FusedIterator for SplitAsciiWhitespace<'_> {}
|
||
|
||
#[unstable(feature = "split_inclusive", issue = "none")]
|
||
impl<'a, P: Pattern<'a>> Iterator for SplitInclusive<'a, P> {
|
||
type Item = &'a str;
|
||
|
||
#[inline]
|
||
fn next(&mut self) -> Option<&'a str> {
|
||
self.0.next_inclusive()
|
||
}
|
||
}
|
||
|
||
#[unstable(feature = "split_inclusive", issue = "none")]
|
||
impl<'a, P: Pattern<'a, Searcher: fmt::Debug>> fmt::Debug for SplitInclusive<'a, P> {
|
||
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
||
f.debug_struct("SplitInclusive").field("0", &self.0).finish()
|
||
}
|
||
}
|
||
|
||
// FIXME(#26925) Remove in favor of `#[derive(Clone)]`
|
||
#[unstable(feature = "split_inclusive", issue = "none")]
|
||
impl<'a, P: Pattern<'a, Searcher: Clone>> Clone for SplitInclusive<'a, P> {
|
||
fn clone(&self) -> Self {
|
||
SplitInclusive(self.0.clone())
|
||
}
|
||
}
|
||
|
||
#[unstable(feature = "split_inclusive", issue = "none")]
|
||
impl<'a, P: Pattern<'a, Searcher: ReverseSearcher<'a>>> DoubleEndedIterator
|
||
for SplitInclusive<'a, P>
|
||
{
|
||
#[inline]
|
||
fn next_back(&mut self) -> Option<&'a str> {
|
||
self.0.next_back_inclusive()
|
||
}
|
||
}
|
||
|
||
#[unstable(feature = "split_inclusive", issue = "none")]
|
||
impl<'a, P: Pattern<'a>> FusedIterator for SplitInclusive<'a, P> {}
|
||
|
||
/// An iterator of [`u16`] over the string encoded as UTF-16.
|
||
///
|
||
/// [`u16`]: ../../std/primitive.u16.html
|
||
///
|
||
/// This struct is created by the [`encode_utf16`] method on [`str`].
|
||
/// See its documentation for more.
|
||
///
|
||
/// [`encode_utf16`]: ../../std/primitive.str.html#method.encode_utf16
|
||
/// [`str`]: ../../std/primitive.str.html
|
||
#[derive(Clone)]
|
||
#[stable(feature = "encode_utf16", since = "1.8.0")]
|
||
pub struct EncodeUtf16<'a> {
|
||
chars: Chars<'a>,
|
||
extra: u16,
|
||
}
|
||
|
||
#[stable(feature = "collection_debug", since = "1.17.0")]
|
||
impl fmt::Debug for EncodeUtf16<'_> {
|
||
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
||
f.pad("EncodeUtf16 { .. }")
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "encode_utf16", since = "1.8.0")]
|
||
impl<'a> Iterator for EncodeUtf16<'a> {
|
||
type Item = u16;
|
||
|
||
#[inline]
|
||
fn next(&mut self) -> Option<u16> {
|
||
if self.extra != 0 {
|
||
let tmp = self.extra;
|
||
self.extra = 0;
|
||
return Some(tmp);
|
||
}
|
||
|
||
let mut buf = [0; 2];
|
||
self.chars.next().map(|ch| {
|
||
let n = ch.encode_utf16(&mut buf).len();
|
||
if n == 2 {
|
||
self.extra = buf[1];
|
||
}
|
||
buf[0]
|
||
})
|
||
}
|
||
|
||
#[inline]
|
||
fn size_hint(&self) -> (usize, Option<usize>) {
|
||
let (low, high) = self.chars.size_hint();
|
||
// every char gets either one u16 or two u16,
|
||
// so this iterator is between 1 or 2 times as
|
||
// long as the underlying iterator.
|
||
(low, high.and_then(|n| n.checked_mul(2)))
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "fused", since = "1.26.0")]
|
||
impl FusedIterator for EncodeUtf16<'_> {}
|
||
|
||
/// The return type of [`str::escape_debug`].
|
||
///
|
||
/// [`str::escape_debug`]: ../../std/primitive.str.html#method.escape_debug
|
||
#[stable(feature = "str_escape", since = "1.34.0")]
|
||
#[derive(Clone, Debug)]
|
||
pub struct EscapeDebug<'a> {
|
||
inner: Chain<
|
||
Flatten<option::IntoIter<char::EscapeDebug>>,
|
||
FlatMap<Chars<'a>, char::EscapeDebug, CharEscapeDebugContinue>,
|
||
>,
|
||
}
|
||
|
||
/// The return type of [`str::escape_default`].
|
||
///
|
||
/// [`str::escape_default`]: ../../std/primitive.str.html#method.escape_default
|
||
#[stable(feature = "str_escape", since = "1.34.0")]
|
||
#[derive(Clone, Debug)]
|
||
pub struct EscapeDefault<'a> {
|
||
inner: FlatMap<Chars<'a>, char::EscapeDefault, CharEscapeDefault>,
|
||
}
|
||
|
||
/// The return type of [`str::escape_unicode`].
|
||
///
|
||
/// [`str::escape_unicode`]: ../../std/primitive.str.html#method.escape_unicode
|
||
#[stable(feature = "str_escape", since = "1.34.0")]
|
||
#[derive(Clone, Debug)]
|
||
pub struct EscapeUnicode<'a> {
|
||
inner: FlatMap<Chars<'a>, char::EscapeUnicode, CharEscapeUnicode>,
|
||
}
|
||
|
||
macro_rules! escape_types_impls {
|
||
($( $Name: ident ),+) => {$(
|
||
#[stable(feature = "str_escape", since = "1.34.0")]
|
||
impl<'a> fmt::Display for $Name<'a> {
|
||
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
||
self.clone().try_for_each(|c| f.write_char(c))
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "str_escape", since = "1.34.0")]
|
||
impl<'a> Iterator for $Name<'a> {
|
||
type Item = char;
|
||
|
||
#[inline]
|
||
fn next(&mut self) -> Option<char> { self.inner.next() }
|
||
|
||
#[inline]
|
||
fn size_hint(&self) -> (usize, Option<usize>) { self.inner.size_hint() }
|
||
|
||
#[inline]
|
||
fn try_fold<Acc, Fold, R>(&mut self, init: Acc, fold: Fold) -> R where
|
||
Self: Sized, Fold: FnMut(Acc, Self::Item) -> R, R: Try<Ok=Acc>
|
||
{
|
||
self.inner.try_fold(init, fold)
|
||
}
|
||
|
||
#[inline]
|
||
fn fold<Acc, Fold>(self, init: Acc, fold: Fold) -> Acc
|
||
where Fold: FnMut(Acc, Self::Item) -> Acc,
|
||
{
|
||
self.inner.fold(init, fold)
|
||
}
|
||
}
|
||
|
||
#[stable(feature = "str_escape", since = "1.34.0")]
|
||
impl<'a> FusedIterator for $Name<'a> {}
|
||
)+}
|
||
}
|
||
|
||
escape_types_impls!(EscapeDebug, EscapeDefault, EscapeUnicode);
|