const fn str::split_at* · qinheping/verify-rust-std@6799f85 (original) (raw)
`@@ -640,7 +640,8 @@ impl str {
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`#[inline]
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`#[must_use]
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`#[stable(feature = "str_split_at", since = "1.4.0")]
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``
`-
pub fn split_at(&self, mid: usize) -> (&str, &str) {
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#[rustc_const_unstable(feature = "const_str_split_at", issue = "131518")]
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``
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pub const fn split_at(&self, mid: usize) -> (&str, &str) {
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`match self.split_at_checked(mid) {
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`None => slice_error_fail(self, 0, mid),
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`Some(pair) => pair,
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`@@ -680,7 +681,8 @@ impl str {
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`#[inline]
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`#[must_use]
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`#[stable(feature = "str_split_at", since = "1.4.0")]
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``
`-
pub fn split_at_mut(&mut self, mid: usize) -> (&mut str, &mut str) {
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``
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#[rustc_const_unstable(feature = "const_str_split_at", issue = "131518")]
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``
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pub const fn split_at_mut(&mut self, mid: usize) -> (&mut str, &mut str) {
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`// is_char_boundary checks that the index is in [0, .len()]
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`if self.is_char_boundary(mid) {
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`` // SAFETY: just checked that mid is on a char boundary.
``
`@@ -719,11 +721,12 @@ impl str {
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`#[inline]
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`#[must_use]
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`#[stable(feature = "split_at_checked", since = "1.80.0")]
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``
`-
pub fn split_at_checked(&self, mid: usize) -> Option<(&str, &str)> {
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#[rustc_const_unstable(feature = "const_str_split_at", issue = "131518")]
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``
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pub const fn split_at_checked(&self, mid: usize) -> Option<(&str, &str)> {
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`// is_char_boundary checks that the index is in [0, .len()]
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`if self.is_char_boundary(mid) {
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`` // SAFETY: just checked that mid is on a char boundary.
``
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``
`-
Some(unsafe { (self.get_unchecked(0..mid), self.get_unchecked(mid..self.len())) })
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Some(unsafe { self.split_at_unchecked(mid) })
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`} else {
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`None
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`}
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`@@ -759,7 +762,9 @@ impl str {
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`#[inline]
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`#[must_use]
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`#[stable(feature = "split_at_checked", since = "1.80.0")]
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``
`-
pub fn split_at_mut_checked(&mut self, mid: usize) -> Option<(&mut str, &mut str)> {
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``
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#[rustc_const_unstable(feature = "const_str_split_at", issue = "131518")]
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#[rustc_allow_const_fn_unstable(const_is_char_boundary)]
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``
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pub const fn split_at_mut_checked(&mut self, mid: usize) -> Option<(&mut str, &mut str)> {
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`// is_char_boundary checks that the index is in [0, .len()]
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`if self.is_char_boundary(mid) {
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`` // SAFETY: just checked that mid is on a char boundary.
``
`@@ -775,7 +780,25 @@ impl str {
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`///
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`` /// The caller must ensure that mid is a valid byte offset from the start
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`/// of the string and falls on the boundary of a UTF-8 code point.
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``
`-
unsafe fn split_at_mut_unchecked(&mut self, mid: usize) -> (&mut str, &mut str) {
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const unsafe fn split_at_unchecked(&self, mid: usize) -> (&str, &str) {
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let len = self.len();
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let ptr = self.as_ptr();
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// SAFETY: caller guarantees mid is on a char boundary.
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unsafe {
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(
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from_utf8_unchecked(slice::from_raw_parts(ptr, mid)),
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from_utf8_unchecked(slice::from_raw_parts(ptr.add(mid), len - mid)),
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)
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}
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}
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``
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/// Divides one string slice into two at an index.
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///
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/// # Safety
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///
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/// The caller must ensure that mid is a valid byte offset from the start
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/// of the string and falls on the boundary of a UTF-8 code point.
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const unsafe fn split_at_mut_unchecked(&mut self, mid: usize) -> (&mut str, &mut str) {
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`let len = self.len();
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`let ptr = self.as_mut_ptr();
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`` // SAFETY: caller guarantees mid is on a char boundary.
``