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fuchsia / third_party / rust / 556fb02e43a16de50764af55db20f64ac17e7f23 / . / src / libcore / str / mod.rs
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// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! String manipulation
//!
//! For more details, see std::str
#![stable(feature = "rust1", since = "1.0.0")]
use self::pattern::Pattern;
use self::pattern::{Searcher, ReverseSearcher, DoubleEndedSearcher};
use char;
use fmt;
use iter::{Map, Cloned, FusedIterator, TrustedLen};
use iter_private::TrustedRandomAccess;
use slice::{self, SliceIndex};
use mem;
pub mod pattern;
/// A trait to abstract the idea of creating a new instance of a type from a
/// string.
///
/// `FromStr`'s [`from_str`] method is often used implicitly, through
/// [`str`]'s [`parse`] method. See [`parse`]'s documentation for examples.
///
/// [`from_str`]: #tymethod.from_str
/// [`str`]: ../../std/primitive.str.html
/// [`parse`]: ../../std/primitive.str.html#method.parse
///
/// # Examples
///
/// Basic implementation of `FromStr` on an example `Point` type:
///
/// ```
/// use std::str::FromStr;
/// use std::num::ParseIntError;
///
/// #[derive(Debug, PartialEq)]
/// struct Point {
/// x: i32,
/// y: i32
/// }
///
/// impl FromStr for Point {
/// type Err = ParseIntError;
///
/// fn from_str(s: &str) -> Result<Self, Self::Err> {
/// let coords: Vec<&str> = s.trim_matches(|p| p == '(' || p == ')' )
/// .split(",")
/// .collect();
///
/// let x_fromstr = coords[0].parse::<i32>()?;
/// let y_fromstr = coords[1].parse::<i32>()?;
///
/// Ok(Point { x: x_fromstr, y: y_fromstr })
/// }
/// }
///
/// let p = Point::from_str("(1,2)");
/// assert_eq!(p.unwrap(), Point{ x: 1, y: 2} )
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub trait FromStr: Sized {
/// The associated error which can be returned from parsing.
#[stable(feature = "rust1", since = "1.0.0")]
type Err;
/// Parses a string `s` to return a value of this type.
///
/// If parsing succeeds, return the value inside [`Ok`], otherwise
/// when the string is ill-formatted return an error specific to the
/// inside [`Err`]. The error type is specific to implementation of the trait.
///
/// [`Ok`]: ../../std/result/enum.Result.html#variant.Ok
/// [`Err`]: ../../std/result/enum.Result.html#variant.Err
///
/// # Examples
///
/// Basic usage with [`i32`][ithirtytwo], a type that implements `FromStr`:
///
/// [ithirtytwo]: ../../std/primitive.i32.html
///
/// ```
/// use std::str::FromStr;
///
/// let s = "5";
/// let x = i32::from_str(s).unwrap();
///
/// assert_eq!(5, x);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
fn from_str(s: &str) -> Result<Self, Self::Err>;
}
#[stable(feature = "rust1", since = "1.0.0")]
impl FromStr for bool {
type Err = ParseBoolError;
/// Parse a `bool` from a string.
///
/// Yields a `Result<bool, ParseBoolError>`, because `s` may or may not
/// actually be parseable.
///
/// # Examples
///
/// ```
/// use std::str::FromStr;
///
/// assert_eq!(FromStr::from_str("true"), Ok(true));
/// assert_eq!(FromStr::from_str("false"), Ok(false));
/// assert!(<bool as FromStr>::from_str("not even a boolean").is_err());
/// ```
///
/// Note, in many cases, the `.parse()` method on `str` is more proper.
///
/// ```
/// assert_eq!("true".parse(), Ok(true));
/// assert_eq!("false".parse(), Ok(false));
/// assert!("not even a boolean".parse::<bool>().is_err());
/// ```
#[inline]
fn from_str(s: &str) -> Result<bool, ParseBoolError> {
match s {
"true" => Ok(true),
"false" => Ok(false),
_ => Err(ParseBoolError { _priv: () }),
}
}
}
/// An error returned when parsing a `bool` using [`from_str`] fails
///
/// [`from_str`]: ../../std/primitive.bool.html#method.from_str
#[derive(Debug, Clone, PartialEq, Eq)]
#[stable(feature = "rust1", since = "1.0.0")]
pub struct ParseBoolError { _priv: () }
#[stable(feature = "rust1", since = "1.0.0")]
impl fmt::Display for ParseBoolError {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
"provided string was not `true` or `false`".fmt(f)
}
}
/*
Section: Creating a string
*/
/// Errors which can occur when attempting to interpret a sequence of [`u8`]
/// as a string.
///
/// [`u8`]: ../../std/primitive.u8.html
///
/// As such, the `from_utf8` family of functions and methods for both [`String`]s
/// and [`&str`]s make use of this error, for example.
///
/// [`String`]: ../../std/string/struct.String.html#method.from_utf8
/// [`&str`]: ../../std/str/fn.from_utf8.html
#[derive(Copy, Eq, PartialEq, Clone, Debug)]
#[stable(feature = "rust1", since = "1.0.0")]
pub struct Utf8Error {
valid_up_to: usize,
error_len: Option<u8>,
}
impl Utf8Error {
/// Returns the index in the given string up to which valid UTF-8 was
/// verified.
///
/// It is the maximum index such that `from_utf8(&input[..index])`
/// would return `Ok(_)`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// use std::str;
///
/// // some invalid bytes, in a vector
/// let sparkle_heart = vec![0, 159, 146, 150];
///
/// // std::str::from_utf8 returns a Utf8Error
/// let error = str::from_utf8(&sparkle_heart).unwrap_err();
///
/// // the second byte is invalid here
/// assert_eq!(1, error.valid_up_to());
/// ```
#[stable(feature = "utf8_error", since = "1.5.0")]
pub fn valid_up_to(&self) -> usize { self.valid_up_to }
/// Provide more information about the failure:
///
/// * `None`: the end of the input was reached unexpectedly.
/// `self.valid_up_to()` is 1 to 3 bytes from the end of the input.
/// If a byte stream (such as a file or a network socket) is being decoded incrementally,
/// this could be a valid `char` whose UTF-8 byte sequence is spanning multiple chunks.
///
/// * `Some(len)`: an unexpected byte was encountered.
/// The length provided is that of the invalid byte sequence
/// that starts at the index given by `valid_up_to()`.
/// Decoding should resume after that sequence
/// (after inserting a U+FFFD REPLACEMENT CHARACTER) in case of lossy decoding.
#[stable(feature = "utf8_error_error_len", since = "1.20.0")]
pub fn error_len(&self) -> Option<usize> {
self.error_len.map(|len| len as usize)
}
}
/// Converts a slice of bytes to a string slice.
///
/// A string slice ([`&str`]) is made of bytes ([`u8`]), and a byte slice
/// ([`&[u8]`][byteslice]) is made of bytes, so this function converts between
/// the two. Not all byte slices are valid string slices, however: [`&str`] requires
/// that it is valid UTF-8. `from_utf8()` checks to ensure that the bytes are valid
/// UTF-8, and then does the conversion.
///
/// [`&str`]: ../../std/primitive.str.html
/// [`u8`]: ../../std/primitive.u8.html
/// [byteslice]: ../../std/primitive.slice.html
///
/// If you are sure that the byte slice is valid UTF-8, and you don't want to
/// incur the overhead of the validity check, there is an unsafe version of
/// this function, [`from_utf8_unchecked`][fromutf8u], which has the same
/// behavior but skips the check.
///
/// [fromutf8u]: fn.from_utf8_unchecked.html
///
/// If you need a `String` instead of a `&str`, consider
/// [`String::from_utf8`][string].
///
/// [string]: ../../std/string/struct.String.html#method.from_utf8
///
/// Because you can stack-allocate a `[u8; N]`, and you can take a
/// [`&[u8]`][byteslice] of it, this function is one way to have a
/// stack-allocated string. There is an example of this in the
/// examples section below.
///
/// [byteslice]: ../../std/primitive.slice.html
///
/// # Errors
///
/// Returns `Err` if the slice is not UTF-8 with a description as to why the
/// provided slice is not UTF-8.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// use std::str;
///
/// // some bytes, in a vector
/// let sparkle_heart = vec![240, 159, 146, 150];
///
/// // We know these bytes are valid, so just use `unwrap()`.
/// let sparkle_heart = str::from_utf8(&sparkle_heart).unwrap();
///
/// assert_eq!("💖", sparkle_heart);
/// ```
///
/// Incorrect bytes:
///
/// ```
/// use std::str;
///
/// // some invalid bytes, in a vector
/// let sparkle_heart = vec![0, 159, 146, 150];
///
/// assert!(str::from_utf8(&sparkle_heart).is_err());
/// ```
///
/// See the docs for [`Utf8Error`][error] for more details on the kinds of
/// errors that can be returned.
///
/// [error]: struct.Utf8Error.html
///
/// A "stack allocated string":
///
/// ```
/// use std::str;
///
/// // some bytes, in a stack-allocated array
/// let sparkle_heart = [240, 159, 146, 150];
///
/// // We know these bytes are valid, so just use `unwrap()`.
/// let sparkle_heart = str::from_utf8(&sparkle_heart).unwrap();
///
/// assert_eq!("💖", sparkle_heart);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn from_utf8(v: &[u8]) -> Result<&str, Utf8Error> {
run_utf8_validation(v)?;
Ok(unsafe { from_utf8_unchecked(v) })
}
/// Converts a mutable slice of bytes to a mutable string slice.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// use std::str;
///
/// // "Hello, Rust!" as a mutable vector
/// let mut hellorust = vec![72, 101, 108, 108, 111, 44, 32, 82, 117, 115, 116, 33];
///
/// // As we know these bytes are valid, we can use `unwrap()`
/// let outstr = str::from_utf8_mut(&mut hellorust).unwrap();
///
/// assert_eq!("Hello, Rust!", outstr);
/// ```
///
/// Incorrect bytes:
///
/// ```
/// use std::str;
///
/// // Some invalid bytes in a mutable vector
/// let mut invalid = vec![128, 223];
///
/// assert!(str::from_utf8_mut(&mut invalid).is_err());
/// ```
/// See the docs for [`Utf8Error`][error] for more details on the kinds of
/// errors that can be returned.
///
/// [error]: struct.Utf8Error.html
#[stable(feature = "str_mut_extras", since = "1.20.0")]
pub fn from_utf8_mut(v: &mut [u8]) -> Result<&mut str, Utf8Error> {
run_utf8_validation(v)?;
Ok(unsafe { from_utf8_unchecked_mut(v) })
}
/// Forms a str from a pointer and a length.
///
/// The `len` argument is the number of bytes in the string.
///
/// # Safety
///
/// This function is unsafe as there is no guarantee that the given pointer is
/// valid for `len` bytes, nor whether the lifetime inferred is a suitable
/// lifetime for the returned str.
///
/// The data must be valid UTF-8
///
/// `p` must be non-null, even for zero-length strs, because non-zero bits
/// are required to distinguish between a zero-length str within `Some()`
/// from `None`. `p` can be a bogus non-dereferencable pointer, such as `0x1`,
/// for zero-length strs, though.
///
/// # Caveat
///
/// The lifetime for the returned str is inferred from its usage. To
/// prevent accidental misuse, it's suggested to tie the lifetime to whichever
/// source lifetime is safe in the context, such as by providing a helper
/// function taking the lifetime of a host value for the str, or by explicit
/// annotation.
/// Performs the same functionality as `from_raw_parts`, except that a mutable
/// str is returned.
///
unsafe fn from_raw_parts_mut<'a>(p: *mut u8, len: usize) -> &'a mut str {
from_utf8_unchecked_mut(slice::from_raw_parts_mut(p, len))
}
/// 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);
/// ```
#[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, Debug)]
#[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 = "0")]
#[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() {
None => return None,
Some(&next_byte) if next_byte < 128 => return Some(next_byte as u32),
Some(&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| {
// 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 = "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| {
// str invariant says `ch` is a valid Unicode Scalar Value
unsafe {
char::from_u32_unchecked(ch)
}
})
}
}
#[unstable(feature = "fused", issue = "35602")]
impl<'a> FusedIterator for Chars<'a> {}
impl<'a> Chars<'a> {
/// View 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 {
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)> {
match self.iter.next_back() {
None => None,
Some(ch) => {
let index = self.front_offset + self.iter.iter.len();
Some((index, ch))
}
}
}
}
#[unstable(feature = "fused", issue = "35602")]
impl<'a> FusedIterator for CharIndices<'a> {}
impl<'a> CharIndices<'a> {
/// View 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>(Cloned<slice::Iter<'a, u8>>);
#[stable(feature = "rust1", since = "1.0.0")]
impl<'a> Iterator for Bytes<'a> {
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<'a> DoubleEndedIterator for Bytes<'a> {
#[inline]
fn next_back(&mut self) -> Option<u8> {
self.0.next_back()
}
#[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<'a> ExactSizeIterator for Bytes<'a> {
#[inline]
fn len(&self) -> usize {
self.0.len()
}
#[inline]
fn is_empty(&self) -> bool {
self.0.is_empty()
}
}
#[unstable(feature = "fused", issue = "35602")]
impl<'a> FusedIterator for Bytes<'a> {}
#[unstable(feature = "trusted_len", issue = "37572")]
unsafe impl<'a> TrustedLen for Bytes<'a> {}
#[doc(hidden)]
unsafe impl<'a> TrustedRandomAccess for Bytes<'a> {
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: Pattern<'a>> Clone for $t<'a, P>
where P::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: Pattern<'a>> fmt::Debug for $forward_iterator<'a, P>
where P::Searcher: fmt::Debug
{
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
f.debug_tuple(stringify!($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: Pattern<'a>> Clone for $forward_iterator<'a, P>
where P::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: Pattern<'a>> fmt::Debug for $reverse_iterator<'a, P>
where P::Searcher: fmt::Debug
{
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
f.debug_tuple(stringify!($reverse_iterator))
.field(&self.0)
.finish()
}
}
$(#[$common_stability_attribute])*
impl<'a, P: Pattern<'a>> Iterator for $reverse_iterator<'a, P>
where P::Searcher: ReverseSearcher<'a>
{
type Item = $iterty;
#[inline]
fn next(&mut self) -> Option<$iterty> {
self.0.next_back()
}
}
$(#[$common_stability_attribute])*
impl<'a, P: Pattern<'a>> Clone for $reverse_iterator<'a, P>
where P::Searcher: Clone
{
fn clone(&self) -> Self {
$reverse_iterator(self.0.clone())
}
}
#[unstable(feature = "fused", issue = "35602")]
impl<'a, P: Pattern<'a>> FusedIterator for $forward_iterator<'a, P> {}
#[unstable(feature = "fused", issue = "35602")]
impl<'a, P: Pattern<'a>> FusedIterator for $reverse_iterator<'a, P>
where P::Searcher: ReverseSearcher<'a> {}
generate_pattern_iterators!($($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: Pattern<'a>> DoubleEndedIterator for $forward_iterator<'a, P>
where P::Searcher: DoubleEndedSearcher<'a>
{
#[inline]
fn next_back(&mut self) -> Option<$iterty> {
self.0.next_back()
}
}
$(#[$common_stability_attribute])*
impl<'a, P: Pattern<'a>> DoubleEndedIterator for $reverse_iterator<'a, P>
where P::Searcher: DoubleEndedSearcher<'a>
{
#[inline]
fn next_back(&mut self) -> Option<$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: Pattern<'a>> fmt::Debug for SplitInternal<'a, P> where P::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;
unsafe {
let string = self.matcher.haystack().slice_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() {
Some((a, b)) => unsafe {
let elt = haystack.slice_unchecked(self.start, a);
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() {
Some((a, b)) => unsafe {
let elt = haystack.slice_unchecked(b, self.end);
self.end = a;
Some(elt)
},
None => unsafe {
self.finished = true;
Some(haystack.slice_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: Pattern<'a>> fmt::Debug for SplitNInternal<'a, P> where P::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: Pattern<'a>> fmt::Debug for MatchIndicesInternal<'a, P> where P::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().map(|(start, end)| unsafe {
(start, self.0.haystack().slice_unchecked(start, end))
})
}
#[inline]
fn next_back(&mut self) -> Option<(usize, &'a str)>
where P::Searcher: ReverseSearcher<'a>
{
self.0.next_match_back().map(|(start, end)| unsafe {
(start, self.0.haystack().slice_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: Pattern<'a>> fmt::Debug for MatchesInternal<'a, P> where P::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> {
self.0.next_match().map(|(a, b)| unsafe {
// Indices are known to be on utf8 boundaries
self.0.haystack().slice_unchecked(a, b)
})
}
#[inline]
fn next_back(&mut self) -> Option<&'a str>
where P::Searcher: ReverseSearcher<'a>
{
self.0.next_match_back().map(|(a, b)| unsafe {
// Indices are known to be on utf8 boundaries
self.0.haystack().slice_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()
}
}
#[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()
}
}
#[unstable(feature = "fused", issue = "35602")]
impl<'a> FusedIterator for Lines<'a> {}
/// 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>);
/// A nameable, cloneable fn type
#[derive(Clone)]
struct LinesAnyMap;
impl<'a> Fn<(&'a str,)> for LinesAnyMap {
#[inline]
extern "rust-call" fn call(&self, (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 }
}
}
impl<'a> FnMut<(&'a str,)> for LinesAnyMap {
#[inline]
extern "rust-call" fn call_mut(&mut self, (line,): (&'a str,)) -> &'a str {
Fn::call(&*self, (line,))
}
}
impl<'a> FnOnce<(&'a str,)> for LinesAnyMap {
type Output = &'a str;
#[inline]
extern "rust-call" fn call_once(self, (line,): (&'a str,)) -> &'a str {
Fn::call(&self, (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()
}
}
#[unstable(feature = "fused", issue = "35602")]
#[allow(deprecated)]
impl<'a> FusedIterator for LinesAny<'a> {}
/*
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 `iter` checking that it's a valid UTF-8 sequence,
/// returning `true` in that case, or, if it is invalid, `false` with
/// `iter` reset such that it is pointing at the first byte in the
/// invalid sequence.
#[inline]
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 };
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.
let ptr = v.as_ptr();
let align = unsafe {
// the offset is safe, because `index` is guaranteed inbounds
ptr.offset(index as isize).align_offset(usize_bytes)
};
if align == 0 {
while index < blocks_end {
unsafe {
let block = ptr.offset(index as isize) 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 = "0")]
#[inline]
pub fn utf8_char_width(b: u8) -> usize {
return 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 cmp::Ordering;
use ops;
use 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))
}
}
/// Implements substring slicing with syntax `&self[begin .. end]`.
///
/// Returns a slice of the given string from the byte range
/// [`begin`..`end`).
///
/// This operation is `O(1)`.
///
/// # Panics
///
/// Panics if `begin` or `end` does not point to the starting
/// byte offset of a character (as defined by `is_char_boundary`).
/// Requires that `begin <= end` and `end <= len` where `len` is the
/// length of the string.
///
/// # 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 = "rust1", since = "1.0.0")]
impl ops::Index<ops::Range<usize>> for str {
type Output = str;
#[inline]
fn index(&self, index: ops::Range<usize>) -> &str {
index.index(self)
}
}
/// Implements mutable substring slicing with syntax
/// `&mut self[begin .. end]`.
///
/// Returns a mutable slice of the given string from the byte range
/// [`begin`..`end`).
///
/// This operation is `O(1)`.
///
/// # Panics
///
/// Panics if `begin` or `end` does not point to the starting
/// byte offset of a character (as defined by `is_char_boundary`).
/// Requires that `begin <= end` and `end <= len` where `len` is the
/// length of the string.
#[stable(feature = "derefmut_for_string", since = "1.3.0")]
impl ops::IndexMut<ops::Range<usize>> for str {
#[inline]
fn index_mut(&mut self, index: ops::Range<usize>) -> &mut str {
index.index_mut(self)
}
}
/// Implements substring slicing with syntax `&self[.. end]`.
///
/// Returns a slice of the string from the beginning to byte offset
/// `end`.
///
/// Equivalent to `&self[0 .. end]`.
#[stable(feature = "rust1", since = "1.0.0")]
impl ops::Index<ops::RangeTo<usize>> for str {
type Output = str;
#[inline]
fn index(&self, index: ops::RangeTo<usize>) -> &str {
index.index(self)
}
}
/// Implements mutable substring slicing with syntax `&mut self[.. end]`.
///
/// Returns a mutable slice of the string from the beginning to byte offset
/// `end`.
///
/// Equivalent to `&mut self[0 .. end]`.
#[stable(feature = "derefmut_for_string", since = "1.3.0")]
impl ops::IndexMut<ops::RangeTo<usize>> for str {
#[inline]
fn index_mut(&mut self, index: ops::RangeTo<usize>) -> &mut str {
index.index_mut(self)
}
}
/// Implements substring slicing with syntax `&self[begin ..]`.
///
/// Returns a slice of the string from byte offset `begin`
/// to the end of the string.
///
/// Equivalent to `&self[begin .. len]`.
#[stable(feature = "rust1", since = "1.0.0")]
impl ops::Index<ops::RangeFrom<usize>> for str {
type Output = str;
#[inline]
fn index(&self, index: ops::RangeFrom<usize>) -> &str {
index.index(self)
}
}
/// Implements mutable substring slicing with syntax `&mut self[begin ..]`.
///
/// Returns a mutable slice of the string from byte offset `begin`
/// to the end of the string.
///
/// Equivalent to `&mut self[begin .. len]`.
#[stable(feature = "derefmut_for_string", since = "1.3.0")]
impl ops::IndexMut<ops::RangeFrom<usize>> for str {
#[inline]
fn index_mut(&mut self, index: ops::RangeFrom<usize>) -> &mut str {
index.index_mut(self)
}
}
/// Implements substring slicing with syntax `&self[..]`.
///
/// Returns a slice of the whole string. This operation can
/// never panic.
///
/// Equivalent to `&self[0 .. len]`.
#[stable(feature = "rust1", since = "1.0.0")]
impl ops::Index<ops::RangeFull> for str {
type Output = str;
#[inline]
fn index(&self, _index: ops::RangeFull) -> &str {
self
}
}
/// Implements mutable substring slicing with syntax `&mut self[..]`.
///
/// Returns a mutable slice of the whole string. This operation can
/// never panic.
///
/// Equivalent to `&mut self[0 .. len]`.
#[stable(feature = "derefmut_for_string", since = "1.3.0")]
impl ops::IndexMut<ops::RangeFull> for str {
#[inline]
fn index_mut(&mut self, _index: ops::RangeFull) -> &mut str {
self
}
}
#[unstable(feature = "inclusive_range",
reason = "recently added, follows RFC",
issue = "28237")]
impl ops::Index<ops::RangeInclusive<usize>> for str {
type Output = str;
#[inline]
fn index(&self, index: ops::RangeInclusive<usize>) -> &str {
index.index(self)
}
}
#[unstable(feature = "inclusive_range",
reason = "recently added, follows RFC",
issue = "28237")]
impl ops::Index<ops::RangeToInclusive<usize>> for str {
type Output = str;
#[inline]
fn index(&self, index: ops::RangeToInclusive<usize>) -> &str {
index.index(self)
}
}
#[unstable(feature = "inclusive_range",
reason = "recently added, follows RFC",
issue = "28237")]
impl ops::IndexMut<ops::RangeInclusive<usize>> for str {
#[inline]
fn index_mut(&mut self, index: ops::RangeInclusive<usize>) -> &mut str {
index.index_mut(self)
}
}
#[unstable(feature = "inclusive_range",
reason = "recently added, follows RFC",
issue = "28237")]
impl ops::IndexMut<ops::RangeToInclusive<usize>> for str {
#[inline]
fn index_mut(&mut self, index: ops::RangeToInclusive<usize>) -> &mut str {
index.index_mut(self)
}
}
#[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
}
}
#[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) {
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) {
Some(unsafe { self.get_unchecked_mut(slice) })
} else {
None
}
}
#[inline]
unsafe fn get_unchecked(self, slice: &str) -> &Self::Output {
let ptr = slice.as_ptr().offset(self.start as isize);
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_ptr().offset(self.start as isize);
let len = self.end - self.start;
super::from_utf8_unchecked_mut(slice::from_raw_parts_mut(ptr as *mut u8, 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()]
// canot 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) {
unsafe { self.get_unchecked_mut(slice) }
} else {
super::slice_error_fail(slice, self.start, self.end)
}
}
}
#[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) {
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) {
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_ptr();
super::from_utf8_unchecked_mut(slice::from_raw_parts_mut(ptr as *mut u8, 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 {
// is_char_boundary checks that the index is in [0, .len()]
if slice.is_char_boundary(self.end) {
unsafe { self.get_unchecked_mut(slice) }
} else {
super::slice_error_fail(slice, 0, self.end)
}
}
}
#[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) {
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) {
Some(unsafe { self.get_unchecked_mut(slice) })
} else {
None
}
}
#[inline]
unsafe fn get_unchecked(self, slice: &str) -> &Self::Output {
let ptr = slice.as_ptr().offset(self.start as isize);
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_ptr().offset(self.start as isize);
let len = slice.len() - self.start;
super::from_utf8_unchecked_mut(slice::from_raw_parts_mut(ptr as *mut u8, 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 {
// is_char_boundary checks that the index is in [0, .len()]
if slice.is_char_boundary(self.start) {
unsafe { self.get_unchecked_mut(slice) }
} else {
super::slice_error_fail(slice, self.start, slice.len())
}
}
}
#[stable(feature = "str_checked_slicing", since = "1.20.0")]
impl SliceIndex<str> for ops::RangeInclusive<usize> {
type Output = str;
#[inline]
fn get(self, slice: &str) -> Option<&Self::Output> {
if let Some(end) = self.end.checked_add(1) {
(self.start..end).get(slice)
} else {
None
}
}
#[inline]
fn get_mut(self, slice: &mut str) -> Option<&mut Self::Output> {
if let Some(end) = self.end.checked_add(1) {
(self.start..end).get_mut(slice)
} else {
None
}
}
#[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 {
assert!(self.end != usize::max_value(),
"attempted to index str up to maximum usize");
(self.start..self.end+1).index(slice)
}
#[inline]
fn index_mut(self, slice: &mut str) -> &mut Self::Output {
assert!(self.end != usize::max_value(),
"attempted to index str up to maximum usize");
(self.start..self.end+1).index_mut(slice)
}
}
#[stable(feature = "str_checked_slicing", since = "1.20.0")]
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() && slice.is_char_boundary(self.end + 1) {
Some(unsafe { self.get_unchecked(slice) })
} else {
None
}
}
#[inline]
fn get_mut(self, slice: &mut str) -> Option<&mut Self::Output> {
if self.end < usize::max_value() && slice.is_char_boundary(self.end + 1) {
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 + 1))
}
#[inline]
unsafe fn get_unchecked_mut(self, slice: &mut str) -> &mut Self::Output {
let ptr = slice.as_ptr();
super::from_utf8_unchecked_mut(slice::from_raw_parts_mut(ptr as *mut u8, self.end + 1))
}
#[inline]
fn index(self, slice: &str) -> &Self::Output {
assert!(self.end != usize::max_value(),
"attempted to index str up to maximum usize");
let end = self.end + 1;
self.get(slice).unwrap_or_else(|| super::slice_error_fail(slice, 0, end))
}
#[inline]
fn index_mut(self, slice: &mut str) -> &mut Self::Output {
assert!(self.end != usize::max_value(),
"attempted to index str up to maximum usize");
if slice.is_char_boundary(self.end) {
unsafe { self.get_unchecked_mut(slice) }
} else {
super::slice_error_fail(slice, 0, self.end + 1)
}
}
}
}
/// Methods for string slices
#[allow(missing_docs)]
#[doc(hidden)]
#[unstable(feature = "core_str_ext",
reason = "stable interface provided by `impl str` in later crates",
issue = "32110")]
pub trait StrExt {
// NB there are no docs here are they're all located on the StrExt trait in
// liballoc, not here.
#[stable(feature = "core", since = "1.6.0")]
fn contains<'a, P: Pattern<'a>>(&'a self, pat: P) -> bool;
#[stable(feature = "core", since = "1.6.0")]
fn chars(&self) -> Chars;
#[stable(feature = "core", since = "1.6.0")]
fn bytes(&self) -> Bytes;
#[stable(feature = "core", since = "1.6.0")]
fn char_indices(&self) -> CharIndices;
#[stable(feature = "core", since = "1.6.0")]
fn split<'a, P: Pattern<'a>>(&'a self, pat: P) -> Split<'a, P>;
#[stable(feature = "core", since = "1.6.0")]
fn rsplit<'a, P: Pattern<'a>>(&'a self, pat: P) -> RSplit<'a, P>
where P::Searcher: ReverseSearcher<'a>;
#[stable(feature = "core", since = "1.6.0")]
fn splitn<'a, P: Pattern<'a>>(&'a self, count: usize, pat: P) -> SplitN<'a, P>;
#[stable(feature = "core", since = "1.6.0")]
fn rsplitn<'a, P: Pattern<'a>>(&'a self, count: usize, pat: P) -> RSplitN<'a, P>
where P::Searcher: ReverseSearcher<'a>;
#[stable(feature = "core", since = "1.6.0")]
fn split_terminator<'a, P: Pattern<'a>>(&'a self, pat: P) -> SplitTerminator<'a, P>;
#[stable(feature = "core", since = "1.6.0")]
fn rsplit_terminator<'a, P: Pattern<'a>>(&'a self, pat: P) -> RSplitTerminator<'a, P>
where P::Searcher: ReverseSearcher<'a>;
#[stable(feature = "core", since = "1.6.0")]
fn matches<'a, P: Pattern<'a>>(&'a self, pat: P) -> Matches<'a, P>;
#[stable(feature = "core", since = "1.6.0")]
fn rmatches<'a, P: Pattern<'a>>(&'a self, pat: P) -> RMatches<'a, P>
where P::Searcher: ReverseSearcher<'a>;
#[stable(feature = "core", since = "1.6.0")]
fn match_indices<'a, P: Pattern<'a>>(&'a self, pat: P) -> MatchIndices<'a, P>;
#[stable(feature = "core", since = "1.6.0")]
fn rmatch_indices<'a, P: Pattern<'a>>(&'a self, pat: P) -> RMatchIndices<'a, P>
where P::Searcher: ReverseSearcher<'a>;
#[stable(feature = "core", since = "1.6.0")]
fn lines(&self) -> Lines;
#[stable(feature = "core", since = "1.6.0")]
#[rustc_deprecated(since = "1.6.0", reason = "use lines() instead now")]
#[allow(deprecated)]
fn lines_any(&self) -> LinesAny;
#[stable(feature = "str_checked_slicing", since = "1.20.0")]
fn get<I: SliceIndex<str>>(&self, i: I) -> Option<&I::Output>;
#[stable(feature = "str_checked_slicing", since = "1.20.0")]
fn get_mut<I: SliceIndex<str>>(&mut self, i: I) -> Option<&mut I::Output>;
#[stable(feature = "str_checked_slicing", since = "1.20.0")]
unsafe fn get_unchecked<I: SliceIndex<str>>(&self, i: I) -> &I::Output;
#[stable(feature = "str_checked_slicing", since = "1.20.0")]
unsafe fn get_unchecked_mut<I: SliceIndex<str>>(&mut self, i: I) -> &mut I::Output;
#[stable(feature = "core", since = "1.6.0")]
unsafe fn slice_unchecked(&self, begin: usize, end: usize) -> &str;
#[stable(feature = "core", since = "1.6.0")]
unsafe fn slice_mut_unchecked(&mut self, begin: usize, end: usize) -> &mut str;
#[stable(feature = "core", since = "1.6.0")]
fn starts_with<'a, P: Pattern<'a>>(&'a self, pat: P) -> bool;
#[stable(feature = "core", since = "1.6.0")]
fn ends_with<'a, P: Pattern<'a>>(&'a self, pat: P) -> bool
where P::Searcher: ReverseSearcher<'a>;
#[stable(feature = "core", since = "1.6.0")]
fn trim_matches<'a, P: Pattern<'a>>(&'a self, pat: P) -> &'a str
where P::Searcher: DoubleEndedSearcher<'a>;
#[stable(feature = "core", since = "1.6.0")]
fn trim_left_matches<'a, P: Pattern<'a>>(&'a self, pat: P) -> &'a str;
#[stable(feature = "core", since = "1.6.0")]
fn trim_right_matches<'a, P: Pattern<'a>>(&'a self, pat: P) -> &'a str
where P::Searcher: ReverseSearcher<'a>;
#[stable(feature = "is_char_boundary", since = "1.9.0")]
fn is_char_boundary(&self, index: usize) -> bool;
#[stable(feature = "core", since = "1.6.0")]
fn as_bytes(&self) -> &[u8];
#[stable(feature = "str_mut_extras", since = "1.20.0")]
unsafe fn as_bytes_mut(&mut self) -> &mut [u8];
#[stable(feature = "core", since = "1.6.0")]
fn find<'a, P: Pattern<'a>>(&'a self, pat: P) -> Option<usize>;
#[stable(feature = "core", since = "1.6.0")]
fn rfind<'a, P: Pattern<'a>>(&'a self, pat: P) -> Option<usize>
where P::Searcher: ReverseSearcher<'a>;
fn find_str<'a, P: Pattern<'a>>(&'a self, pat: P) -> Option<usize>;
#[stable(feature = "core", since = "1.6.0")]
fn split_at(&self, mid: usize) -> (&str, &str);
#[stable(feature = "core", since = "1.6.0")]
fn split_at_mut(&mut self, mid: usize) -> (&mut str, &mut str);
#[stable(feature = "core", since = "1.6.0")]
fn as_ptr(&self) -> *const u8;
#[stable(feature = "core", since = "1.6.0")]
fn len(&self) -> usize;
#[stable(feature = "core", since = "1.6.0")]
fn is_empty(&self) -> bool;
#[stable(feature = "core", since = "1.6.0")]
fn parse<T: FromStr>(&self) -> Result<T, T::Err>;
}
// 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);
}
#[stable(feature = "core", since = "1.6.0")]
impl StrExt for str {
#[inline]
fn contains<'a, P: Pattern<'a>>(&'a self, pat: P) -> bool {
pat.is_contained_in(self)
}
#[inline]
fn chars(&self) -> Chars {
Chars{iter: self.as_bytes().iter()}
}
#[inline]
fn bytes(&self) -> Bytes {
Bytes(self.as_bytes().iter().cloned())
}
#[inline]
fn char_indices(&self) -> CharIndices {
CharIndices { front_offset: 0, iter: self.chars() }
}
#[inline]
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,
})
}
#[inline]
fn rsplit<'a, P: Pattern<'a>>(&'a self, pat: P) -> RSplit<'a, P>
where P::Searcher: ReverseSearcher<'a>
{
RSplit(self.split(pat).0)
}
#[inline]
fn splitn<'a, P: Pattern<'a>>(&'a self, count: usize, pat: P) -> SplitN<'a, P> {
SplitN(SplitNInternal {
iter: self.split(pat).0,
count,
})
}
#[inline]
fn rsplitn<'a, P: Pattern<'a>>(&'a self, count: usize, pat: P) -> RSplitN<'a, P>
where P::Searcher: ReverseSearcher<'a>
{
RSplitN(self.splitn(count, pat).0)
}
#[inline]
fn split_terminator<'a, P: Pattern<'a>>(&'a self, pat: P) -> SplitTerminator<'a, P> {
SplitTerminator(SplitInternal {
allow_trailing_empty: false,
..self.split(pat).0
})
}
#[inline]
fn rsplit_terminator<'a, P: Pattern<'a>>(&'a self, pat: P) -> RSplitTerminator<'a, P>
where P::Searcher: ReverseSearcher<'a>
{
RSplitTerminator(self.split_terminator(pat).0)
}
#[inline]
fn matches<'a, P: Pattern<'a>>(&'a self, pat: P) -> Matches<'a, P> {
Matches(MatchesInternal(pat.into_searcher(self)))
}
#[inline]
fn rmatches<'a, P: Pattern<'a>>(&'a self, pat: P) -> RMatches<'a, P>
where P::Searcher: ReverseSearcher<'a>
{
RMatches(self.matches(pat).0)
}
#[inline]
fn match_indices<'a, P: Pattern<'a>>(&'a self, pat: P) -> MatchIndices<'a, P> {
MatchIndices(MatchIndicesInternal(pat.into_searcher(self)))
}
#[inline]
fn rmatch_indices<'a, P: Pattern<'a>>(&'a self, pat: P) -> RMatchIndices<'a, P>
where P::Searcher: ReverseSearcher<'a>
{
RMatchIndices(self.match_indices(pat).0)
}
#[inline]
fn lines(&self) -> Lines {
Lines(self.split_terminator('\n').map(LinesAnyMap))
}
#[inline]
#[allow(deprecated)]
fn lines_any(&self) -> LinesAny {
LinesAny(self.lines())
}
#[inline]
fn get<I: SliceIndex<str>>(&self, i: I) -> Option<&I::Output> {
i.get(self)
}
#[inline]
fn get_mut<I: SliceIndex<str>>(&mut self, i: I) -> Option<&mut I::Output> {
i.get_mut(self)
}
#[inline]
unsafe fn get_unchecked<I: SliceIndex<str>>(&self, i: I) -> &I::Output {
i.get_unchecked(self)
}
#[inline]
unsafe fn get_unchecked_mut<I: SliceIndex<str>>(&mut self, i: I) -> &mut I::Output {
i.get_unchecked_mut(self)
}
#[inline]
unsafe fn slice_unchecked(&self, begin: usize, end: usize) -> &str {
(begin..end).get_unchecked(self)
}
#[inline]
unsafe fn slice_mut_unchecked(&mut self, begin: usize, end: usize) -> &mut str {
(begin..end).get_unchecked_mut(self)
}
#[inline]
fn starts_with<'a, P: Pattern<'a>>(&'a self, pat: P) -> bool {
pat.is_prefix_of(self)
}
#[inline]
fn ends_with<'a, P: Pattern<'a>>(&'a self, pat: P) -> bool
where P::Searcher: ReverseSearcher<'a>
{
pat.is_suffix_of(self)
}
#[inline]
fn trim_matches<'a, P: Pattern<'a>>(&'a self, pat: P) -> &'a str
where P::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;
}
unsafe {
// Searcher is known to return valid indices
self.slice_unchecked(i, j)
}
}
#[inline]
fn trim_left_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;
}
unsafe {
// Searcher is known to return valid indices
self.slice_unchecked(i, self.len())
}
}
#[inline]
fn trim_right_matches<'a, P: Pattern<'a>>(&'a self, pat: P) -> &'a str
where P::Searcher: ReverseSearcher<'a>
{
let mut j = 0;
let mut matcher = pat.into_searcher(self);
if let Some((_, b)) = matcher.next_reject_back() {
j = b;
}
unsafe {
// Searcher is known to return valid indices
self.slice_unchecked(0, j)
}
}
#[inline]
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,
}
}
#[inline]
fn as_bytes(&self) -> &[u8] {
unsafe { &*(self as *const str as *const [u8]) }
}
#[inline]
unsafe fn as_bytes_mut(&mut self) -> &mut [u8] {
&mut *(self as *mut str as *mut [u8])
}
fn find<'a, P: Pattern<'a>>(&'a self, pat: P) -> Option<usize> {
pat.into_searcher(self).next_match().map(|(i, _)| i)
}
fn rfind<'a, P: Pattern<'a>>(&'a self, pat: P) -> Option<usize>
where P::Searcher: ReverseSearcher<'a>
{
pat.into_searcher(self).next_match_back().map(|(i, _)| i)
}
fn find_str<'a, P: Pattern<'a>>(&'a self, pat: P) -> Option<usize> {
self.find(pat)
}
#[inline]
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) {
unsafe {
(self.slice_unchecked(0, mid),
self.slice_unchecked(mid, self.len()))
}
} else {
slice_error_fail(self, 0, mid)
}
}
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_ptr() as *mut u8;
unsafe {
(from_raw_parts_mut(ptr, mid),
from_raw_parts_mut(ptr.offset(mid as isize), len - mid))
}
} else {
slice_error_fail(self, 0, mid)
}
}
#[inline]
fn as_ptr(&self) -> *const u8 {
self as *const str as *const u8
}
#[inline]
fn len(&self) -> usize {
self.as_bytes().len()
}
#[inline]
fn is_empty(&self) -> bool { self.len() == 0 }
#[inline]
fn parse<T: FromStr>(&self) -> Result<T, T::Err> { FromStr::from_str(self) }
}
#[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<'a> Default for &'a str {
/// Creates an empty str
fn default() -> &'a str { "" }
}