diff options
| -rw-r--r-- | library/core/src/char/convert.rs | 38 |
1 files changed, 36 insertions, 2 deletions
diff --git a/library/core/src/char/convert.rs b/library/core/src/char/convert.rs index b84e4b35b1c..b6b36886604 100644 --- a/library/core/src/char/convert.rs +++ b/library/core/src/char/convert.rs @@ -87,20 +87,54 @@ impl From<char> for u128 { } } -/// Map `char` with code point in U+0000..=U+00FF to byte in 0x00..=0xFF with same value, failing -/// if the code point is greater than U+00FF. +/// Maps a `char` with code point in U+0000..=U+00FF to a byte in 0x00..=0xFF with same value, +/// failing if the code point is greater than U+00FF. /// /// See [`impl From<u8> for char`](char#impl-From<u8>-for-char) for details on the encoding. #[stable(feature = "u8_from_char", since = "1.59.0")] impl TryFrom<char> for u8 { type Error = TryFromCharError; + /// Tries to convert a [`char`] into a [`u8`]. + /// + /// # Examples + /// + /// ``` + /// let a = 'ÿ'; // U+00FF + /// let b = 'Ā'; // U+0100 + /// assert_eq!(u8::try_from(a), Ok(0xFF_u8)); + /// assert!(u8::try_from(b).is_err()); + /// ``` #[inline] fn try_from(c: char) -> Result<u8, Self::Error> { u8::try_from(u32::from(c)).map_err(|_| TryFromCharError(())) } } +/// Maps a `char` with code point in U+0000..=U+FFFF to a `u16` in 0x0000..=0xFFFF with same value, +/// failing if the code point is greater than U+FFFF. +/// +/// This corresponds to the UCS-2 encoding, as specified in ISO/IEC 10646:2003. +#[stable(feature = "u16_from_char", since = "CURRENT_RUSTC_VERSION")] +impl TryFrom<char> for u16 { + type Error = TryFromCharError; + + /// Tries to convert a [`char`] into a [`u16`]. + /// + /// # Examples + /// + /// ``` + /// let trans_rights = '⚧'; // U+26A7 + /// let ninjas = '🥷'; // U+1F977 + /// assert_eq!(u16::try_from(trans_rights), Ok(0x26A7_u16)); + /// assert!(u16::try_from(ninjas).is_err()); + /// ``` + #[inline] + fn try_from(c: char) -> Result<u16, Self::Error> { + u16::try_from(u32::from(c)).map_err(|_| TryFromCharError(())) + } +} + /// Maps a byte in 0x00..=0xFF to a `char` whose code point has the same value, in U+0000..=U+00FF. /// /// Unicode is designed such that this effectively decodes bytes |