blob: 13734c04c8e05a80e5df6d70bb5fc9a08247df42 [file] [log] [blame]
//! Iterators for `str` methods.
use crate::char;
use crate::fmt::{self, Write};
use crate::iter::{Chain, FlatMap, Flatten};
use crate::iter::{Copied, Filter, FusedIterator, Map, TrustedLen};
use crate::iter::{TrustedRandomAccess, TrustedRandomAccessNoCoerce};
use crate::ops::Try;
use crate::option;
use crate::slice::{self, Split as SliceSplit};
use super::from_utf8_unchecked;
use super::pattern::Pattern;
use super::pattern::{DoubleEndedSearcher, ReverseSearcher, Searcher};
use super::validations::{next_code_point, next_code_point_reverse};
use super::LinesAnyMap;
use super::{BytesIsNotEmpty, UnsafeBytesToStr};
use super::{CharEscapeDebugContinue, CharEscapeDefault, CharEscapeUnicode};
use super::{IsAsciiWhitespace, IsNotEmpty, IsWhitespace};
/// An iterator over the [`char`]s of a string slice.
///
///
/// This struct is created by the [`chars`] method on [`str`].
/// See its documentation for more.
///
/// [`char`]: prim@char
/// [`chars`]: str::chars
#[derive(Clone)]
#[must_use = "iterators are lazy and do nothing unless consumed"]
#[stable(feature = "rust1", since = "1.0.0")]
pub struct Chars<'a> {
pub(super) iter: slice::Iter<'a, u8>,
}
#[stable(feature = "rust1", since = "1.0.0")]
impl<'a> Iterator for Chars<'a> {
type Item = char;
#[inline]
fn next(&mut self) -> Option<char> {
// SAFETY: `str` invariant says `self.iter` is a valid UTF-8 string and
// the resulting `ch` is a valid Unicode Scalar Value.
unsafe { next_code_point(&mut self.iter).map(|ch| char::from_u32_unchecked(ch)) }
}
#[inline]
fn count(self) -> usize {
super::count::count_chars(self.as_str())
}
#[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> {
// SAFETY: `str` invariant says `self.iter` is a valid UTF-8 string and
// the resulting `ch` is a valid Unicode Scalar Value.
unsafe { next_code_point_reverse(&mut self.iter).map(|ch| 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")]
#[must_use]
#[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.
///
/// This struct is created by the [`char_indices`] method on [`str`].
/// See its documentation for more.
///
/// [`char`]: prim@char
/// [`char_indices`]: str::char_indices
#[derive(Clone, Debug)]
#[must_use = "iterators are lazy and do nothing unless consumed"]
#[stable(feature = "rust1", since = "1.0.0")]
pub struct CharIndices<'a> {
pub(super) front_offset: usize,
pub(super) 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")]
#[must_use]
#[inline]
pub fn as_str(&self) -> &'a str {
self.iter.as_str()
}
/// Returns the byte position of the next character, or the length
/// of the underlying string if there are no more characters.
///
/// # Examples
///
/// ```
/// #![feature(char_indices_offset)]
/// let mut chars = "a楽".char_indices();
///
/// assert_eq!(chars.offset(), 0);
/// assert_eq!(chars.next(), Some((0, 'a')));
///
/// assert_eq!(chars.offset(), 1);
/// assert_eq!(chars.next(), Some((1, '楽')));
///
/// assert_eq!(chars.offset(), 4);
/// assert_eq!(chars.next(), None);
/// ```
#[inline]
#[must_use]
#[unstable(feature = "char_indices_offset", issue = "83871")]
pub fn offset(&self) -> usize {
self.front_offset
}
}
/// 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`]: str::bytes
#[must_use = "iterators are lazy and do nothing unless consumed"]
#[stable(feature = "rust1", since = "1.0.0")]
#[derive(Clone, Debug)]
pub struct Bytes<'a>(pub(super) 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)
}
#[inline]
unsafe fn __iterator_get_unchecked(&mut self, idx: usize) -> u8 {
// SAFETY: the caller must uphold the safety contract
// for `Iterator::__iterator_get_unchecked`.
unsafe { self.0.__iterator_get_unchecked(idx) }
}
}
#[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)]
#[unstable(feature = "trusted_random_access", issue = "none")]
unsafe impl TrustedRandomAccess for Bytes<'_> {}
#[doc(hidden)]
#[unstable(feature = "trusted_random_access", issue = "none")]
unsafe impl TrustedRandomAccessNoCoerce for Bytes<'_> {
const 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>>(pub(super) $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>>(pub(super) $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 }
}
pub(super) struct SplitInternal<'a, P: Pattern<'a>> {
pub(super) start: usize,
pub(super) end: usize,
pub(super) matcher: P::Searcher,
pub(super) allow_trailing_empty: bool,
pub(super) 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))
},
}
}
#[inline]
fn as_str(&self) -> &'a str {
// `Self::get_end` doesn't change `self.start`
if self.finished {
return "";
}
// SAFETY: `self.start` and `self.end` always lie on unicode boundaries.
unsafe { self.matcher.haystack().get_unchecked(self.start..self.end) }
}
}
generate_pattern_iterators! {
forward:
/// Created with the method [`split`].
///
/// [`split`]: str::split
struct Split;
reverse:
/// Created with the method [`rsplit`].
///
/// [`rsplit`]: str::rsplit
struct RSplit;
stability:
#[stable(feature = "rust1", since = "1.0.0")]
internal:
SplitInternal yielding (&'a str);
delegate double ended;
}
impl<'a, P: Pattern<'a>> Split<'a, P> {
/// Returns remainder of the split string
///
/// # Examples
///
/// ```
/// #![feature(str_split_as_str)]
/// let mut split = "Mary had a little lamb".split(' ');
/// assert_eq!(split.as_str(), "Mary had a little lamb");
/// split.next();
/// assert_eq!(split.as_str(), "had a little lamb");
/// split.by_ref().for_each(drop);
/// assert_eq!(split.as_str(), "");
/// ```
#[inline]
#[unstable(feature = "str_split_as_str", issue = "77998")]
pub fn as_str(&self) -> &'a str {
self.0.as_str()
}
}
impl<'a, P: Pattern<'a>> RSplit<'a, P> {
/// Returns remainder of the split string
///
/// # Examples
///
/// ```
/// #![feature(str_split_as_str)]
/// let mut split = "Mary had a little lamb".rsplit(' ');
/// assert_eq!(split.as_str(), "Mary had a little lamb");
/// split.next();
/// assert_eq!(split.as_str(), "Mary had a little");
/// split.by_ref().for_each(drop);
/// assert_eq!(split.as_str(), "");
/// ```
#[inline]
#[unstable(feature = "str_split_as_str", issue = "77998")]
pub fn as_str(&self) -> &'a str {
self.0.as_str()
}
}
generate_pattern_iterators! {
forward:
/// Created with the method [`split_terminator`].
///
/// [`split_terminator`]: str::split_terminator
struct SplitTerminator;
reverse:
/// Created with the method [`rsplit_terminator`].
///
/// [`rsplit_terminator`]: str::rsplit_terminator
struct RSplitTerminator;
stability:
#[stable(feature = "rust1", since = "1.0.0")]
internal:
SplitInternal yielding (&'a str);
delegate double ended;
}
impl<'a, P: Pattern<'a>> SplitTerminator<'a, P> {
/// Returns remainder of the split string
///
/// # Examples
///
/// ```
/// #![feature(str_split_as_str)]
/// let mut split = "A..B..".split_terminator('.');
/// assert_eq!(split.as_str(), "A..B..");
/// split.next();
/// assert_eq!(split.as_str(), ".B..");
/// split.by_ref().for_each(drop);
/// assert_eq!(split.as_str(), "");
/// ```
#[inline]
#[unstable(feature = "str_split_as_str", issue = "77998")]
pub fn as_str(&self) -> &'a str {
self.0.as_str()
}
}
impl<'a, P: Pattern<'a>> RSplitTerminator<'a, P> {
/// Returns remainder of the split string
///
/// # Examples
///
/// ```
/// #![feature(str_split_as_str)]
/// let mut split = "A..B..".rsplit_terminator('.');
/// assert_eq!(split.as_str(), "A..B..");
/// split.next();
/// assert_eq!(split.as_str(), "A..B");
/// split.by_ref().for_each(drop);
/// assert_eq!(split.as_str(), "");
/// ```
#[inline]
#[unstable(feature = "str_split_as_str", issue = "77998")]
pub fn as_str(&self) -> &'a str {
self.0.as_str()
}
}
derive_pattern_clone! {
clone SplitNInternal
with |s| SplitNInternal { iter: s.iter.clone(), ..*s }
}
pub(super) struct SplitNInternal<'a, P: Pattern<'a>> {
pub(super) iter: SplitInternal<'a, P>,
/// The number of splits remaining
pub(super) 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()
}
}
}
#[inline]
fn as_str(&self) -> &'a str {
self.iter.as_str()
}
}
generate_pattern_iterators! {
forward:
/// Created with the method [`splitn`].
///
/// [`splitn`]: str::splitn
struct SplitN;
reverse:
/// Created with the method [`rsplitn`].
///
/// [`rsplitn`]: str::rsplitn
struct RSplitN;
stability:
#[stable(feature = "rust1", since = "1.0.0")]
internal:
SplitNInternal yielding (&'a str);
delegate single ended;
}
impl<'a, P: Pattern<'a>> SplitN<'a, P> {
/// Returns remainder of the split string
///
/// # Examples
///
/// ```
/// #![feature(str_split_as_str)]
/// let mut split = "Mary had a little lamb".splitn(3, ' ');
/// assert_eq!(split.as_str(), "Mary had a little lamb");
/// split.next();
/// assert_eq!(split.as_str(), "had a little lamb");
/// split.by_ref().for_each(drop);
/// assert_eq!(split.as_str(), "");
/// ```
#[inline]
#[unstable(feature = "str_split_as_str", issue = "77998")]
pub fn as_str(&self) -> &'a str {
self.0.as_str()
}
}
impl<'a, P: Pattern<'a>> RSplitN<'a, P> {
/// Returns remainder of the split string
///
/// # Examples
///
/// ```
/// #![feature(str_split_as_str)]
/// let mut split = "Mary had a little lamb".rsplitn(3, ' ');
/// assert_eq!(split.as_str(), "Mary had a little lamb");
/// split.next();
/// assert_eq!(split.as_str(), "Mary had a little");
/// split.by_ref().for_each(drop);
/// assert_eq!(split.as_str(), "");
/// ```
#[inline]
#[unstable(feature = "str_split_as_str", issue = "77998")]
pub fn as_str(&self) -> &'a str {
self.0.as_str()
}
}
derive_pattern_clone! {
clone MatchIndicesInternal
with |s| MatchIndicesInternal(s.0.clone())
}
pub(super) struct MatchIndicesInternal<'a, P: Pattern<'a>>(pub(super) 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`]: str::match_indices
struct MatchIndices;
reverse:
/// Created with the method [`rmatch_indices`].
///
/// [`rmatch_indices`]: str::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())
}
pub(super) struct MatchesInternal<'a, P: Pattern<'a>>(pub(super) 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`]: str::matches
struct Matches;
reverse:
/// Created with the method [`rmatches`].
///
/// [`rmatches`]: str::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`]: str::lines
#[stable(feature = "rust1", since = "1.0.0")]
#[must_use = "iterators are lazy and do nothing unless consumed"]
#[derive(Clone, Debug)]
pub struct Lines<'a>(pub(super) 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`]: str::lines_any
#[stable(feature = "rust1", since = "1.0.0")]
#[deprecated(since = "1.4.0", note = "use lines()/Lines instead now")]
#[must_use = "iterators are lazy and do nothing unless consumed"]
#[derive(Clone, Debug)]
#[allow(deprecated)]
pub struct LinesAny<'a>(pub(super) Lines<'a>);
#[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<'_> {}
/// 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`]: str::split_whitespace
#[stable(feature = "split_whitespace", since = "1.1.0")]
#[derive(Clone, Debug)]
pub struct SplitWhitespace<'a> {
pub(super) 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`]: str::split_ascii_whitespace
#[stable(feature = "split_ascii_whitespace", since = "1.34.0")]
#[derive(Clone, Debug)]
pub struct SplitAsciiWhitespace<'a> {
pub(super) 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`]: str::split_inclusive
#[stable(feature = "split_inclusive", since = "1.51.0")]
pub struct SplitInclusive<'a, P: Pattern<'a>>(pub(super) SplitInternal<'a, P>);
#[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<'_> {}
impl<'a> SplitWhitespace<'a> {
/// Returns remainder of the split string
///
/// # Examples
///
/// ```
/// #![feature(str_split_whitespace_as_str)]
///
/// let mut split = "Mary had a little lamb".split_whitespace();
/// assert_eq!(split.as_str(), "Mary had a little lamb");
///
/// split.next();
/// assert_eq!(split.as_str(), "had a little lamb");
///
/// split.by_ref().for_each(drop);
/// assert_eq!(split.as_str(), "");
/// ```
#[inline]
#[must_use]
#[unstable(feature = "str_split_whitespace_as_str", issue = "77998")]
pub fn as_str(&self) -> &'a str {
self.inner.iter.as_str()
}
}
#[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<'_> {}
impl<'a> SplitAsciiWhitespace<'a> {
/// Returns remainder of the split string
///
/// # Examples
///
/// ```
/// #![feature(str_split_whitespace_as_str)]
///
/// let mut split = "Mary had a little lamb".split_ascii_whitespace();
/// assert_eq!(split.as_str(), "Mary had a little lamb");
///
/// split.next();
/// assert_eq!(split.as_str(), "had a little lamb");
///
/// split.by_ref().for_each(drop);
/// assert_eq!(split.as_str(), "");
/// ```
#[inline]
#[must_use]
#[unstable(feature = "str_split_whitespace_as_str", issue = "77998")]
pub fn as_str(&self) -> &'a str {
if self.inner.iter.iter.finished {
return "";
}
// SAFETY: Slice is created from str.
unsafe { crate::str::from_utf8_unchecked(&self.inner.iter.iter.v) }
}
}
#[stable(feature = "split_inclusive", since = "1.51.0")]
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()
}
}
#[stable(feature = "split_inclusive", since = "1.51.0")]
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)]`
#[stable(feature = "split_inclusive", since = "1.51.0")]
impl<'a, P: Pattern<'a, Searcher: Clone>> Clone for SplitInclusive<'a, P> {
fn clone(&self) -> Self {
SplitInclusive(self.0.clone())
}
}
#[stable(feature = "split_inclusive", since = "1.51.0")]
impl<'a, P: Pattern<'a, Searcher: DoubleEndedSearcher<'a>>> DoubleEndedIterator
for SplitInclusive<'a, P>
{
#[inline]
fn next_back(&mut self) -> Option<&'a str> {
self.0.next_back_inclusive()
}
}
#[stable(feature = "split_inclusive", since = "1.51.0")]
impl<'a, P: Pattern<'a>> FusedIterator for SplitInclusive<'a, P> {}
impl<'a, P: Pattern<'a>> SplitInclusive<'a, P> {
/// Returns remainder of the split string
///
/// # Examples
///
/// ```
/// #![feature(str_split_inclusive_as_str)]
/// let mut split = "Mary had a little lamb".split_inclusive(' ');
/// assert_eq!(split.as_str(), "Mary had a little lamb");
/// split.next();
/// assert_eq!(split.as_str(), "had a little lamb");
/// split.by_ref().for_each(drop);
/// assert_eq!(split.as_str(), "");
/// ```
#[inline]
#[unstable(feature = "str_split_inclusive_as_str", issue = "77998")]
pub fn as_str(&self) -> &'a str {
self.0.as_str()
}
}
/// An iterator of [`u16`] over the string encoded as UTF-16.
///
/// This struct is created by the [`encode_utf16`] method on [`str`].
/// See its documentation for more.
///
/// [`encode_utf16`]: str::encode_utf16
#[derive(Clone)]
#[stable(feature = "encode_utf16", since = "1.8.0")]
pub struct EncodeUtf16<'a> {
pub(super) chars: Chars<'a>,
pub(super) 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.debug_struct("EncodeUtf16").finish_non_exhaustive()
}
}
#[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`].
#[stable(feature = "str_escape", since = "1.34.0")]
#[derive(Clone, Debug)]
pub struct EscapeDebug<'a> {
pub(super) inner: Chain<
Flatten<option::IntoIter<char::EscapeDebug>>,
FlatMap<Chars<'a>, char::EscapeDebug, CharEscapeDebugContinue>,
>,
}
/// The return type of [`str::escape_default`].
#[stable(feature = "str_escape", since = "1.34.0")]
#[derive(Clone, Debug)]
pub struct EscapeDefault<'a> {
pub(super) inner: FlatMap<Chars<'a>, char::EscapeDefault, CharEscapeDefault>,
}
/// The return type of [`str::escape_unicode`].
#[stable(feature = "str_escape", since = "1.34.0")]
#[derive(Clone, Debug)]
pub struct EscapeUnicode<'a> {
pub(super) 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<Output = 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);