diff options
| -rw-r--r-- | src/libcore/char.rs | 34 | ||||
| -rw-r--r-- | src/libcoretest/char.rs | 8 |
2 files changed, 42 insertions, 0 deletions
diff --git a/src/libcore/char.rs b/src/libcore/char.rs index 4677f0b523f..47a8678d608 100644 --- a/src/libcore/char.rs +++ b/src/libcore/char.rs @@ -175,6 +175,40 @@ pub unsafe fn from_u32_unchecked(i: u32) -> char { transmute(i) } +#[stable(feature = "char_convert", since = "1.13.0")] +impl From<char> for u32 { + #[inline] + fn from(c: char) -> Self { + c as u32 + } +} + +/// Maps a byte in 0x00...0xFF to a `char` whose code point has the same value, in U+0000 to U+00FF. +/// +/// Unicode is designed such that this effectively decodes bytes +/// with the character encoding that IANA calls ISO-8859-1. +/// This encoding is compatible with ASCII. +/// +/// Note that this is different from ISO/IEC 8859-1 a.k.a. ISO 8859-1 (with one less hypen), +/// which leaves some "blanks", byte values that are not assigned to any character. +/// ISO-8859-1 (the IANA one) assigns them to the C0 and C1 control codes. +/// +/// Note that this is *also* different from Windows-1252 a.k.a. code page 1252, +/// which is a superset ISO/IEC 8859-1 that assigns some (not all!) blanks +/// to punctuation and various Latin characters. +/// +/// To confuse things further, [on the Web](https://encoding.spec.whatwg.org/) +/// `ascii`, `iso-8859-1`, and `windows-1252` are all aliases +/// for a superset of Windows-1252 that fills the remaining blanks with corresponding +/// C0 and C1 control codes. +#[stable(feature = "char_convert", since = "1.13.0")] +impl From<u8> for char { + #[inline] + fn from(i: u8) -> Self { + i as char + } +} + /// Converts a digit in the given radix to a `char`. /// /// A 'radix' here is sometimes also called a 'base'. A radix of two diff --git a/src/libcoretest/char.rs b/src/libcoretest/char.rs index 333503d7389..92a2b23d242 100644 --- a/src/libcoretest/char.rs +++ b/src/libcoretest/char.rs @@ -11,6 +11,14 @@ use std::char; #[test] +fn test_convert() { + assert_eq!(u32::from('a'), 0x61); + assert_eq!(char::from(b'\0'), '\0'); + assert_eq!(char::from(b'a'), 'a'); + assert_eq!(char::from(b'\xFF'), '\u{FF}'); +} + +#[test] fn test_is_lowercase() { assert!('a'.is_lowercase()); assert!('รถ'.is_lowercase()); |