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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
commit | 698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch) | |
tree | 173a775858bd501c378080a10dca74132f05bc50 /library/std/src/ascii.rs | |
parent | Initial commit. (diff) | |
download | rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip |
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'library/std/src/ascii.rs')
-rw-r--r-- | library/std/src/ascii.rs | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/library/std/src/ascii.rs b/library/std/src/ascii.rs new file mode 100644 index 000000000..c29f01577 --- /dev/null +++ b/library/std/src/ascii.rs @@ -0,0 +1,208 @@ +//! Operations on ASCII strings and characters. +//! +//! Most string operations in Rust act on UTF-8 strings. However, at times it +//! makes more sense to only consider the ASCII character set for a specific +//! operation. +//! +//! The [`AsciiExt`] trait provides methods that allow for character +//! operations that only act on the ASCII subset and leave non-ASCII characters +//! alone. +//! +//! The [`escape_default`] function provides an iterator over the bytes of an +//! escaped version of the character given. + +#![stable(feature = "rust1", since = "1.0.0")] + +#[stable(feature = "rust1", since = "1.0.0")] +pub use core::ascii::{escape_default, EscapeDefault}; + +/// Extension methods for ASCII-subset only operations. +/// +/// Be aware that operations on seemingly non-ASCII characters can sometimes +/// have unexpected results. Consider this example: +/// +/// ``` +/// use std::ascii::AsciiExt; +/// +/// assert_eq!(AsciiExt::to_ascii_uppercase("café"), "CAFÉ"); +/// assert_eq!(AsciiExt::to_ascii_uppercase("café"), "CAFé"); +/// ``` +/// +/// In the first example, the lowercased string is represented `"cafe\u{301}"` +/// (the last character is an acute accent [combining character]). Unlike the +/// other characters in the string, the combining character will not get mapped +/// to an uppercase variant, resulting in `"CAFE\u{301}"`. In the second +/// example, the lowercased string is represented `"caf\u{e9}"` (the last +/// character is a single Unicode character representing an 'e' with an acute +/// accent). Since the last character is defined outside the scope of ASCII, +/// it will not get mapped to an uppercase variant, resulting in `"CAF\u{e9}"`. +/// +/// [combining character]: https://en.wikipedia.org/wiki/Combining_character +#[stable(feature = "rust1", since = "1.0.0")] +#[deprecated(since = "1.26.0", note = "use inherent methods instead")] +pub trait AsciiExt { + /// Container type for copied ASCII characters. + #[stable(feature = "rust1", since = "1.0.0")] + type Owned; + + /// Checks if the value is within the ASCII range. + /// + /// # Note + /// + /// This method is deprecated in favor of the identically-named + /// inherent methods on `u8`, `char`, `[u8]` and `str`. + #[stable(feature = "rust1", since = "1.0.0")] + fn is_ascii(&self) -> bool; + + /// Makes a copy of the value in its ASCII upper case equivalent. + /// + /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z', + /// but non-ASCII letters are unchanged. + /// + /// To uppercase the value in-place, use [`make_ascii_uppercase`]. + /// + /// To uppercase ASCII characters in addition to non-ASCII characters, use + /// [`str::to_uppercase`]. + /// + /// # Note + /// + /// This method is deprecated in favor of the identically-named + /// inherent methods on `u8`, `char`, `[u8]` and `str`. + /// + /// [`make_ascii_uppercase`]: AsciiExt::make_ascii_uppercase + #[stable(feature = "rust1", since = "1.0.0")] + #[allow(deprecated)] + fn to_ascii_uppercase(&self) -> Self::Owned; + + /// Makes a copy of the value in its ASCII lower case equivalent. + /// + /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z', + /// but non-ASCII letters are unchanged. + /// + /// To lowercase the value in-place, use [`make_ascii_lowercase`]. + /// + /// To lowercase ASCII characters in addition to non-ASCII characters, use + /// [`str::to_lowercase`]. + /// + /// # Note + /// + /// This method is deprecated in favor of the identically-named + /// inherent methods on `u8`, `char`, `[u8]` and `str`. + /// + /// [`make_ascii_lowercase`]: AsciiExt::make_ascii_lowercase + #[stable(feature = "rust1", since = "1.0.0")] + #[allow(deprecated)] + fn to_ascii_lowercase(&self) -> Self::Owned; + + /// Checks that two values are an ASCII case-insensitive match. + /// + /// Same as `to_ascii_lowercase(a) == to_ascii_lowercase(b)`, + /// but without allocating and copying temporaries. + /// + /// # Note + /// + /// This method is deprecated in favor of the identically-named + /// inherent methods on `u8`, `char`, `[u8]` and `str`. + #[stable(feature = "rust1", since = "1.0.0")] + fn eq_ignore_ascii_case(&self, other: &Self) -> bool; + + /// Converts this type to its ASCII upper case equivalent in-place. + /// + /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z', + /// but non-ASCII letters are unchanged. + /// + /// To return a new uppercased value without modifying the existing one, use + /// [`to_ascii_uppercase`]. + /// + /// # Note + /// + /// This method is deprecated in favor of the identically-named + /// inherent methods on `u8`, `char`, `[u8]` and `str`. + /// + /// [`to_ascii_uppercase`]: AsciiExt::to_ascii_uppercase + #[stable(feature = "ascii", since = "1.9.0")] + fn make_ascii_uppercase(&mut self); + + /// Converts this type to its ASCII lower case equivalent in-place. + /// + /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z', + /// but non-ASCII letters are unchanged. + /// + /// To return a new lowercased value without modifying the existing one, use + /// [`to_ascii_lowercase`]. + /// + /// # Note + /// + /// This method is deprecated in favor of the identically-named + /// inherent methods on `u8`, `char`, `[u8]` and `str`. + /// + /// [`to_ascii_lowercase`]: AsciiExt::to_ascii_lowercase + #[stable(feature = "ascii", since = "1.9.0")] + fn make_ascii_lowercase(&mut self); +} + +macro_rules! delegating_ascii_methods { + () => { + #[inline] + fn is_ascii(&self) -> bool { + self.is_ascii() + } + + #[inline] + fn to_ascii_uppercase(&self) -> Self::Owned { + self.to_ascii_uppercase() + } + + #[inline] + fn to_ascii_lowercase(&self) -> Self::Owned { + self.to_ascii_lowercase() + } + + #[inline] + fn eq_ignore_ascii_case(&self, o: &Self) -> bool { + self.eq_ignore_ascii_case(o) + } + + #[inline] + fn make_ascii_uppercase(&mut self) { + self.make_ascii_uppercase(); + } + + #[inline] + fn make_ascii_lowercase(&mut self) { + self.make_ascii_lowercase(); + } + }; +} + +#[stable(feature = "rust1", since = "1.0.0")] +#[allow(deprecated)] +impl AsciiExt for u8 { + type Owned = u8; + + delegating_ascii_methods!(); +} + +#[stable(feature = "rust1", since = "1.0.0")] +#[allow(deprecated)] +impl AsciiExt for char { + type Owned = char; + + delegating_ascii_methods!(); +} + +#[stable(feature = "rust1", since = "1.0.0")] +#[allow(deprecated)] +impl AsciiExt for [u8] { + type Owned = Vec<u8>; + + delegating_ascii_methods!(); +} + +#[stable(feature = "rust1", since = "1.0.0")] +#[allow(deprecated)] +impl AsciiExt for str { + type Owned = String; + + delegating_ascii_methods!(); +} |