diff --git a/library/core/src/num/mod.rs b/library/core/src/num/mod.rs index f0bd976ba83..6032dc9a2d3 100644 --- a/library/core/src/num/mod.rs +++ b/library/core/src/num/mod.rs @@ -2,6 +2,7 @@ #![stable(feature = "rust1", since = "1.0.0")] +use crate::ascii; use crate::intrinsics; use crate::mem; use crate::str::FromStr; @@ -661,6 +662,31 @@ impl u8 { pub const fn is_ascii_control(&self) -> bool { matches!(*self, b'\0'..=b'\x1F' | b'\x7F') } + + /// Returns an iterator that produces an escaped version of a `u8`, + /// treating it as an ASCII character. + /// + /// The behavior is identical to [`ascii::escape_default`]. + /// + /// # Examples + /// + /// ``` + /// #![feature(inherent_ascii_escape)] + /// + /// assert_eq!("0", b'0'.escape_ascii().to_string()); + /// assert_eq!("\\t", b'\t'.escape_ascii().to_string()); + /// assert_eq!("\\r", b'\r'.escape_ascii().to_string()); + /// assert_eq!("\\n", b'\n'.escape_ascii().to_string()); + /// assert_eq!("\\'", b'\''.escape_ascii().to_string()); + /// assert_eq!("\\\"", b'"'.escape_ascii().to_string()); + /// assert_eq!("\\\\", b'\\'.escape_ascii().to_string()); + /// assert_eq!("\\x9d", b'\x9d'.escape_ascii().to_string()); + /// ``` + #[unstable(feature = "inherent_ascii_escape", issue = "77174")] + #[inline] + pub fn escape_ascii(&self) -> ascii::EscapeDefault { + ascii::escape_default(*self) + } } #[lang = "u16"] diff --git a/library/core/src/slice/ascii.rs b/library/core/src/slice/ascii.rs index 009ef9e0a9c..22fa08b9795 100644 --- a/library/core/src/slice/ascii.rs +++ b/library/core/src/slice/ascii.rs @@ -1,7 +1,10 @@ //! Operations on ASCII `[u8]`. +use crate::ascii; +use crate::fmt::{self, Write}; use crate::iter; use crate::mem; +use crate::ops; #[lang = "slice_u8"] #[cfg(not(test))] @@ -56,6 +59,95 @@ impl [u8] { byte.make_ascii_lowercase(); } } + + /// Returns an iterator that produces an escaped version of this slice, + /// treating it as an ASCII string. + /// + /// # Examples + /// + /// ``` + /// #![feature(inherent_ascii_escape)] + /// + /// let s = b"0\t\r\n'\"\\\x9d"; + /// let escaped = s.escape_ascii().to_string(); + /// assert_eq!(escaped, "0\\t\\r\\n\\'\\\"\\\\\\x9d"); + /// ``` + #[unstable(feature = "inherent_ascii_escape", issue = "77174")] + pub fn escape_ascii(&self) -> EscapeAscii<'_> { + EscapeAscii { inner: self.iter().flat_map(EscapeByte) } + } +} + +impl_fn_for_zst! { + #[derive(Clone)] + struct EscapeByte impl Fn = |byte: &u8| -> ascii::EscapeDefault { + ascii::escape_default(*byte) + }; +} + +/// An iterator over the escaped version of a byte slice. +/// +/// This `struct` is created by the [`slice::escape_ascii`] method. See its +/// documentation for more information. +#[unstable(feature = "inherent_ascii_escape", issue = "77174")] +#[derive(Clone)] +pub struct EscapeAscii<'a> { + inner: iter::FlatMap, ascii::EscapeDefault, EscapeByte>, +} + +#[unstable(feature = "inherent_ascii_escape", issue = "77174")] +impl<'a> iter::Iterator for EscapeAscii<'a> { + type Item = u8; + #[inline] + fn next(&mut self) -> Option { + self.inner.next() + } + #[inline] + fn size_hint(&self) -> (usize, Option) { + self.inner.size_hint() + } + #[inline] + fn try_fold(&mut self, init: Acc, fold: Fold) -> R + where + Fold: FnMut(Acc, Self::Item) -> R, + R: ops::Try, + { + self.inner.try_fold(init, fold) + } + #[inline] + fn fold(self, init: Acc, fold: Fold) -> Acc + where + Fold: FnMut(Acc, Self::Item) -> Acc, + { + self.inner.fold(init, fold) + } + #[inline] + fn last(mut self) -> Option { + self.next_back() + } +} + +#[unstable(feature = "inherent_ascii_escape", issue = "77174")] +impl<'a> iter::DoubleEndedIterator for EscapeAscii<'a> { + fn next_back(&mut self) -> Option { + self.inner.next_back() + } +} +#[unstable(feature = "inherent_ascii_escape", issue = "77174")] +impl<'a> iter::ExactSizeIterator for EscapeAscii<'a> {} +#[unstable(feature = "inherent_ascii_escape", issue = "77174")] +impl<'a> iter::FusedIterator for EscapeAscii<'a> {} +#[unstable(feature = "inherent_ascii_escape", issue = "77174")] +impl<'a> fmt::Display for EscapeAscii<'a> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.clone().try_for_each(|b| f.write_char(b as char)) + } +} +#[unstable(feature = "inherent_ascii_escape", issue = "77174")] +impl<'a> fmt::Debug for EscapeAscii<'a> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.pad("EscapeAscii { .. }") + } } /// Returns `true` if any byte in the word `v` is nonascii (>= 128). Snarfed diff --git a/library/core/src/slice/mod.rs b/library/core/src/slice/mod.rs index d7a28c8d08f..59fad8c813c 100644 --- a/library/core/src/slice/mod.rs +++ b/library/core/src/slice/mod.rs @@ -81,6 +81,9 @@ pub use index::SliceIndex; #[unstable(feature = "slice_range", issue = "76393")] pub use index::range; +#[unstable(feature = "inherent_ascii_escape", issue = "77174")] +pub use ascii::EscapeAscii; + #[lang = "slice"] #[cfg(not(test))] impl [T] {