blob: fe5d16862a6a673e1d9bdf93bd6a4affa49c77d2 [file] [log] [blame]
//! impl char {}
use crate::slice;
use crate::str::from_utf8_unchecked_mut;
use crate::unicode::printable::is_printable;
use crate::unicode::tables::{conversions, derived_property, general_category, property};
use super::*;
#[lang = "char"]
impl char {
/// Checks if a `char` is a digit in the given radix.
///
/// A 'radix' here is sometimes also called a 'base'. A radix of two
/// indicates a binary number, a radix of ten, decimal, and a radix of
/// sixteen, hexadecimal, to give some common values. Arbitrary
/// radices are supported.
///
/// Compared to `is_numeric()`, this function only recognizes the characters
/// `0-9`, `a-z` and `A-Z`.
///
/// 'Digit' is defined to be only the following characters:
///
/// * `0-9`
/// * `a-z`
/// * `A-Z`
///
/// For a more comprehensive understanding of 'digit', see [`is_numeric`][is_numeric].
///
/// [is_numeric]: #method.is_numeric
///
/// # Panics
///
/// Panics if given a radix larger than 36.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert!('1'.is_digit(10));
/// assert!('f'.is_digit(16));
/// assert!(!'f'.is_digit(10));
/// ```
///
/// Passing a large radix, causing a panic:
///
/// ```
/// use std::thread;
///
/// let result = thread::spawn(|| {
/// // this panics
/// '1'.is_digit(37);
/// }).join();
///
/// assert!(result.is_err());
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn is_digit(self, radix: u32) -> bool {
self.to_digit(radix).is_some()
}
/// Converts a `char` to a digit in the given radix.
///
/// A 'radix' here is sometimes also called a 'base'. A radix of two
/// indicates a binary number, a radix of ten, decimal, and a radix of
/// sixteen, hexadecimal, to give some common values. Arbitrary
/// radices are supported.
///
/// 'Digit' is defined to be only the following characters:
///
/// * `0-9`
/// * `a-z`
/// * `A-Z`
///
/// # Errors
///
/// Returns `None` if the `char` does not refer to a digit in the given radix.
///
/// # Panics
///
/// Panics if given a radix larger than 36.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!('1'.to_digit(10), Some(1));
/// assert_eq!('f'.to_digit(16), Some(15));
/// ```
///
/// Passing a non-digit results in failure:
///
/// ```
/// assert_eq!('f'.to_digit(10), None);
/// assert_eq!('z'.to_digit(16), None);
/// ```
///
/// Passing a large radix, causing a panic:
///
/// ```
/// use std::thread;
///
/// let result = thread::spawn(|| {
/// '1'.to_digit(37);
/// }).join();
///
/// assert!(result.is_err());
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn to_digit(self, radix: u32) -> Option<u32> {
assert!(radix <= 36, "to_digit: radix is too high (maximum 36)");
// the code is split up here to improve execution speed for cases where
// the `radix` is constant and 10 or smaller
let val = if radix <= 10 {
match self {
'0'..='9' => self as u32 - '0' as u32,
_ => return None,
}
} else {
match self {
'0'..='9' => self as u32 - '0' as u32,
'a'..='z' => self as u32 - 'a' as u32 + 10,
'A'..='Z' => self as u32 - 'A' as u32 + 10,
_ => return None,
}
};
if val < radix { Some(val) } else { None }
}
/// Returns an iterator that yields the hexadecimal Unicode escape of a
/// character as `char`s.
///
/// This will escape characters with the Rust syntax of the form
/// `\u{NNNNNN}` where `NNNNNN` is a hexadecimal representation.
///
/// # Examples
///
/// As an iterator:
///
/// ```
/// for c in '❤'.escape_unicode() {
/// print!("{}", c);
/// }
/// println!();
/// ```
///
/// Using `println!` directly:
///
/// ```
/// println!("{}", '❤'.escape_unicode());
/// ```
///
/// Both are equivalent to:
///
/// ```
/// println!("\\u{{2764}}");
/// ```
///
/// Using `to_string`:
///
/// ```
/// assert_eq!('❤'.escape_unicode().to_string(), "\\u{2764}");
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn escape_unicode(self) -> EscapeUnicode {
let c = self as u32;
// or-ing 1 ensures that for c==0 the code computes that one
// digit should be printed and (which is the same) avoids the
// (31 - 32) underflow
let msb = 31 - (c | 1).leading_zeros();
// the index of the most significant hex digit
let ms_hex_digit = msb / 4;
EscapeUnicode {
c: self,
state: EscapeUnicodeState::Backslash,
hex_digit_idx: ms_hex_digit as usize,
}
}
/// An extended version of `escape_debug` that optionally permits escaping
/// Extended Grapheme codepoints. This allows us to format characters like
/// nonspacing marks better when they're at the start of a string.
#[inline]
pub(crate) fn escape_debug_ext(self, escape_grapheme_extended: bool) -> EscapeDebug {
let init_state = match self {
'\t' => EscapeDefaultState::Backslash('t'),
'\r' => EscapeDefaultState::Backslash('r'),
'\n' => EscapeDefaultState::Backslash('n'),
'\\' | '\'' | '"' => EscapeDefaultState::Backslash(self),
_ if escape_grapheme_extended && self.is_grapheme_extended() => {
EscapeDefaultState::Unicode(self.escape_unicode())
}
_ if is_printable(self) => EscapeDefaultState::Char(self),
_ => EscapeDefaultState::Unicode(self.escape_unicode()),
};
EscapeDebug(EscapeDefault { state: init_state })
}
/// Returns an iterator that yields the literal escape code of a character
/// as `char`s.
///
/// This will escape the characters similar to the `Debug` implementations
/// of `str` or `char`.
///
/// # Examples
///
/// As an iterator:
///
/// ```
/// for c in '\n'.escape_debug() {
/// print!("{}", c);
/// }
/// println!();
/// ```
///
/// Using `println!` directly:
///
/// ```
/// println!("{}", '\n'.escape_debug());
/// ```
///
/// Both are equivalent to:
///
/// ```
/// println!("\\n");
/// ```
///
/// Using `to_string`:
///
/// ```
/// assert_eq!('\n'.escape_debug().to_string(), "\\n");
/// ```
#[stable(feature = "char_escape_debug", since = "1.20.0")]
#[inline]
pub fn escape_debug(self) -> EscapeDebug {
self.escape_debug_ext(true)
}
/// Returns an iterator that yields the literal escape code of a character
/// as `char`s.
///
/// The default is chosen with a bias toward producing literals that are
/// legal in a variety of languages, including C++11 and similar C-family
/// languages. The exact rules are:
///
/// * Tab is escaped as `\t`.
/// * Carriage return is escaped as `\r`.
/// * Line feed is escaped as `\n`.
/// * Single quote is escaped as `\'`.
/// * Double quote is escaped as `\"`.
/// * Backslash is escaped as `\\`.
/// * Any character in the 'printable ASCII' range `0x20` .. `0x7e`
/// inclusive is not escaped.
/// * All other characters are given hexadecimal Unicode escapes; see
/// [`escape_unicode`][escape_unicode].
///
/// [escape_unicode]: #method.escape_unicode
///
/// # Examples
///
/// As an iterator:
///
/// ```
/// for c in '"'.escape_default() {
/// print!("{}", c);
/// }
/// println!();
/// ```
///
/// Using `println!` directly:
///
/// ```
/// println!("{}", '"'.escape_default());
/// ```
///
///
/// Both are equivalent to:
///
/// ```
/// println!("\\\"");
/// ```
///
/// Using `to_string`:
///
/// ```
/// assert_eq!('"'.escape_default().to_string(), "\\\"");
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn escape_default(self) -> EscapeDefault {
let init_state = match self {
'\t' => EscapeDefaultState::Backslash('t'),
'\r' => EscapeDefaultState::Backslash('r'),
'\n' => EscapeDefaultState::Backslash('n'),
'\\' | '\'' | '"' => EscapeDefaultState::Backslash(self),
'\x20'..='\x7e' => EscapeDefaultState::Char(self),
_ => EscapeDefaultState::Unicode(self.escape_unicode()),
};
EscapeDefault { state: init_state }
}
/// Returns the number of bytes this `char` would need if encoded in UTF-8.
///
/// That number of bytes is always between 1 and 4, inclusive.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// let len = 'A'.len_utf8();
/// assert_eq!(len, 1);
///
/// let len = 'ß'.len_utf8();
/// assert_eq!(len, 2);
///
/// let len = 'ℝ'.len_utf8();
/// assert_eq!(len, 3);
///
/// let len = '💣'.len_utf8();
/// assert_eq!(len, 4);
/// ```
///
/// The `&str` type guarantees that its contents are UTF-8, and so we can compare the length it
/// would take if each code point was represented as a `char` vs in the `&str` itself:
///
/// ```
/// // as chars
/// let eastern = '東';
/// let capital = '京';
///
/// // both can be represented as three bytes
/// assert_eq!(3, eastern.len_utf8());
/// assert_eq!(3, capital.len_utf8());
///
/// // as a &str, these two are encoded in UTF-8
/// let tokyo = "東京";
///
/// let len = eastern.len_utf8() + capital.len_utf8();
///
/// // we can see that they take six bytes total...
/// assert_eq!(6, tokyo.len());
///
/// // ... just like the &str
/// assert_eq!(len, tokyo.len());
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn len_utf8(self) -> usize {
let code = self as u32;
if code < MAX_ONE_B {
1
} else if code < MAX_TWO_B {
2
} else if code < MAX_THREE_B {
3
} else {
4
}
}
/// Returns the number of 16-bit code units this `char` would need if
/// encoded in UTF-16.
///
/// See the documentation for [`len_utf8`] for more explanation of this
/// concept. This function is a mirror, but for UTF-16 instead of UTF-8.
///
/// [`len_utf8`]: #method.len_utf8
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// let n = 'ß'.len_utf16();
/// assert_eq!(n, 1);
///
/// let len = '💣'.len_utf16();
/// assert_eq!(len, 2);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn len_utf16(self) -> usize {
let ch = self as u32;
if (ch & 0xFFFF) == ch { 1 } else { 2 }
}
/// Encodes this character as UTF-8 into the provided byte buffer,
/// and then returns the subslice of the buffer that contains the encoded character.
///
/// # Panics
///
/// Panics if the buffer is not large enough.
/// A buffer of length four is large enough to encode any `char`.
///
/// # Examples
///
/// In both of these examples, 'ß' takes two bytes to encode.
///
/// ```
/// let mut b = [0; 2];
///
/// let result = 'ß'.encode_utf8(&mut b);
///
/// assert_eq!(result, "ß");
///
/// assert_eq!(result.len(), 2);
/// ```
///
/// A buffer that's too small:
///
/// ```
/// use std::thread;
///
/// let result = thread::spawn(|| {
/// let mut b = [0; 1];
///
/// // this panics
/// 'ß'.encode_utf8(&mut b);
/// }).join();
///
/// assert!(result.is_err());
/// ```
#[stable(feature = "unicode_encode_char", since = "1.15.0")]
#[inline]
pub fn encode_utf8(self, dst: &mut [u8]) -> &mut str {
let code = self as u32;
let len = self.len_utf8();
match (len, &mut dst[..]) {
(1, [a, ..]) => {
*a = code as u8;
}
(2, [a, b, ..]) => {
*a = (code >> 6 & 0x1F) as u8 | TAG_TWO_B;
*b = (code & 0x3F) as u8 | TAG_CONT;
}
(3, [a, b, c, ..]) => {
*a = (code >> 12 & 0x0F) as u8 | TAG_THREE_B;
*b = (code >> 6 & 0x3F) as u8 | TAG_CONT;
*c = (code & 0x3F) as u8 | TAG_CONT;
}
(4, [a, b, c, d, ..]) => {
*a = (code >> 18 & 0x07) as u8 | TAG_FOUR_B;
*b = (code >> 12 & 0x3F) as u8 | TAG_CONT;
*c = (code >> 6 & 0x3F) as u8 | TAG_CONT;
*d = (code & 0x3F) as u8 | TAG_CONT;
}
_ => panic!(
"encode_utf8: need {} bytes to encode U+{:X}, but the buffer has {}",
len,
code,
dst.len(),
),
};
// SAFETY: We just wrote UTF-8 content in, so converting to str is fine.
unsafe { from_utf8_unchecked_mut(&mut dst[..len]) }
}
/// Encodes this character as UTF-16 into the provided `u16` buffer,
/// and then returns the subslice of the buffer that contains the encoded character.
///
/// # Panics
///
/// Panics if the buffer is not large enough.
/// A buffer of length 2 is large enough to encode any `char`.
///
/// # Examples
///
/// In both of these examples, '𝕊' takes two `u16`s to encode.
///
/// ```
/// let mut b = [0; 2];
///
/// let result = '𝕊'.encode_utf16(&mut b);
///
/// assert_eq!(result.len(), 2);
/// ```
///
/// A buffer that's too small:
///
/// ```
/// use std::thread;
///
/// let result = thread::spawn(|| {
/// let mut b = [0; 1];
///
/// // this panics
/// '𝕊'.encode_utf16(&mut b);
/// }).join();
///
/// assert!(result.is_err());
/// ```
#[stable(feature = "unicode_encode_char", since = "1.15.0")]
#[inline]
pub fn encode_utf16(self, dst: &mut [u16]) -> &mut [u16] {
let mut code = self as u32;
// SAFETY: each arm checks whether there are enough bits to write into
unsafe {
if (code & 0xFFFF) == code && !dst.is_empty() {
// The BMP falls through (assuming non-surrogate, as it should)
*dst.get_unchecked_mut(0) = code as u16;
slice::from_raw_parts_mut(dst.as_mut_ptr(), 1)
} else if dst.len() >= 2 {
// Supplementary planes break into surrogates.
code -= 0x1_0000;
*dst.get_unchecked_mut(0) = 0xD800 | ((code >> 10) as u16);
*dst.get_unchecked_mut(1) = 0xDC00 | ((code as u16) & 0x3FF);
slice::from_raw_parts_mut(dst.as_mut_ptr(), 2)
} else {
panic!(
"encode_utf16: need {} units to encode U+{:X}, but the buffer has {}",
from_u32_unchecked(code).len_utf16(),
code,
dst.len(),
)
}
}
}
/// Returns `true` if this `char` has the `Alphabetic` property.
///
/// `Alphabetic` is described in Chapter 4 (Character Properties) of the [Unicode Standard] and
/// specified in the [Unicode Character Database][ucd] [`DerivedCoreProperties.txt`].
///
/// [Unicode Standard]: https://www.unicode.org/versions/latest/
/// [ucd]: https://www.unicode.org/reports/tr44/
/// [`DerivedCoreProperties.txt`]: https://www.unicode.org/Public/UCD/latest/ucd/DerivedCoreProperties.txt
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert!('a'.is_alphabetic());
/// assert!('京'.is_alphabetic());
///
/// let c = '💝';
/// // love is many things, but it is not alphabetic
/// assert!(!c.is_alphabetic());
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn is_alphabetic(self) -> bool {
match self {
'a'..='z' | 'A'..='Z' => true,
c => c > '\x7f' && derived_property::Alphabetic(c),
}
}
/// Returns `true` if this `char` has the `Lowercase` property.
///
/// `Lowercase` is described in Chapter 4 (Character Properties) of the [Unicode Standard] and
/// specified in the [Unicode Character Database][ucd] [`DerivedCoreProperties.txt`].
///
/// [Unicode Standard]: https://www.unicode.org/versions/latest/
/// [ucd]: https://www.unicode.org/reports/tr44/
/// [`DerivedCoreProperties.txt`]: https://www.unicode.org/Public/UCD/latest/ucd/DerivedCoreProperties.txt
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert!('a'.is_lowercase());
/// assert!('δ'.is_lowercase());
/// assert!(!'A'.is_lowercase());
/// assert!(!'Δ'.is_lowercase());
///
/// // The various Chinese scripts do not have case, and so:
/// assert!(!'中'.is_lowercase());
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn is_lowercase(self) -> bool {
match self {
'a'..='z' => true,
c => c > '\x7f' && derived_property::Lowercase(c),
}
}
/// Returns `true` if this `char` has the `Uppercase` property.
///
/// `Uppercase` is described in Chapter 4 (Character Properties) of the [Unicode Standard] and
/// specified in the [Unicode Character Database][ucd] [`DerivedCoreProperties.txt`].
///
/// [Unicode Standard]: https://www.unicode.org/versions/latest/
/// [ucd]: https://www.unicode.org/reports/tr44/
/// [`DerivedCoreProperties.txt`]: https://www.unicode.org/Public/UCD/latest/ucd/DerivedCoreProperties.txt
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert!(!'a'.is_uppercase());
/// assert!(!'δ'.is_uppercase());
/// assert!('A'.is_uppercase());
/// assert!('Δ'.is_uppercase());
///
/// // The various Chinese scripts do not have case, and so:
/// assert!(!'中'.is_uppercase());
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn is_uppercase(self) -> bool {
match self {
'A'..='Z' => true,
c => c > '\x7f' && derived_property::Uppercase(c),
}
}
/// Returns `true` if this `char` has the `White_Space` property.
///
/// `White_Space` is specified in the [Unicode Character Database][ucd] [`PropList.txt`].
///
/// [ucd]: https://www.unicode.org/reports/tr44/
/// [`PropList.txt`]: https://www.unicode.org/Public/UCD/latest/ucd/PropList.txt
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert!(' '.is_whitespace());
///
/// // a non-breaking space
/// assert!('\u{A0}'.is_whitespace());
///
/// assert!(!'越'.is_whitespace());
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn is_whitespace(self) -> bool {
match self {
' ' | '\x09'..='\x0d' => true,
c => c > '\x7f' && property::White_Space(c),
}
}
/// Returns `true` if this `char` satisfies either [`is_alphabetic()`] or [`is_numeric()`].
///
/// [`is_alphabetic()`]: #method.is_alphabetic
/// [`is_numeric()`]: #method.is_numeric
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert!('٣'.is_alphanumeric());
/// assert!('7'.is_alphanumeric());
/// assert!('৬'.is_alphanumeric());
/// assert!('¾'.is_alphanumeric());
/// assert!('①'.is_alphanumeric());
/// assert!('K'.is_alphanumeric());
/// assert!('و'.is_alphanumeric());
/// assert!('藏'.is_alphanumeric());
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn is_alphanumeric(self) -> bool {
self.is_alphabetic() || self.is_numeric()
}
/// Returns `true` if this `char` has the general category for control codes.
///
/// Control codes (code points with the general category of `Cc`) are described in Chapter 4
/// (Character Properties) of the [Unicode Standard] and specified in the [Unicode Character
/// Database][ucd] [`UnicodeData.txt`].
///
/// [Unicode Standard]: https://www.unicode.org/versions/latest/
/// [ucd]: https://www.unicode.org/reports/tr44/
/// [`UnicodeData.txt`]: https://www.unicode.org/Public/UCD/latest/ucd/UnicodeData.txt
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// // U+009C, STRING TERMINATOR
/// assert!('œ'.is_control());
/// assert!(!'q'.is_control());
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn is_control(self) -> bool {
general_category::Cc(self)
}
/// Returns `true` if this `char` has the `Grapheme_Extend` property.
///
/// `Grapheme_Extend` is described in [Unicode Standard Annex #29 (Unicode Text
/// Segmentation)][uax29] and specified in the [Unicode Character Database][ucd]
/// [`DerivedCoreProperties.txt`].
///
/// [uax29]: https://www.unicode.org/reports/tr29/
/// [ucd]: https://www.unicode.org/reports/tr44/
/// [`DerivedCoreProperties.txt`]: https://www.unicode.org/Public/UCD/latest/ucd/DerivedCoreProperties.txt
#[inline]
pub(crate) fn is_grapheme_extended(self) -> bool {
derived_property::Grapheme_Extend(self)
}
/// Returns `true` if this `char` has one of the general categories for numbers.
///
/// The general categories for numbers (`Nd` for decimal digits, `Nl` for letter-like numeric
/// characters, and `No` for other numeric characters) are specified in the [Unicode Character
/// Database][ucd] [`UnicodeData.txt`].
///
/// [Unicode Standard]: https://www.unicode.org/versions/latest/
/// [ucd]: https://www.unicode.org/reports/tr44/
/// [`UnicodeData.txt`]: https://www.unicode.org/Public/UCD/latest/ucd/UnicodeData.txt
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert!('٣'.is_numeric());
/// assert!('7'.is_numeric());
/// assert!('৬'.is_numeric());
/// assert!('¾'.is_numeric());
/// assert!('①'.is_numeric());
/// assert!(!'K'.is_numeric());
/// assert!(!'و'.is_numeric());
/// assert!(!'藏'.is_numeric());
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn is_numeric(self) -> bool {
match self {
'0'..='9' => true,
c => c > '\x7f' && general_category::N(c),
}
}
/// Returns an iterator that yields the lowercase mapping of this `char` as one or more
/// `char`s.
///
/// If this `char` does not have a lowercase mapping, the iterator yields the same `char`.
///
/// If this `char` has a one-to-one lowercase mapping given by the [Unicode Character
/// Database][ucd] [`UnicodeData.txt`], the iterator yields that `char`.
///
/// [ucd]: https://www.unicode.org/reports/tr44/
/// [`UnicodeData.txt`]: https://www.unicode.org/Public/UCD/latest/ucd/UnicodeData.txt
///
/// If this `char` requires special considerations (e.g. multiple `char`s) the iterator yields
/// the `char`(s) given by [`SpecialCasing.txt`].
///
/// [`SpecialCasing.txt`]: https://www.unicode.org/Public/UCD/latest/ucd/SpecialCasing.txt
///
/// This operation performs an unconditional mapping without tailoring. That is, the conversion
/// is independent of context and language.
///
/// In the [Unicode Standard], Chapter 4 (Character Properties) discusses case mapping in
/// general and Chapter 3 (Conformance) discusses the default algorithm for case conversion.
///
/// [Unicode Standard]: https://www.unicode.org/versions/latest/
///
/// # Examples
///
/// As an iterator:
///
/// ```
/// for c in 'İ'.to_lowercase() {
/// print!("{}", c);
/// }
/// println!();
/// ```
///
/// Using `println!` directly:
///
/// ```
/// println!("{}", 'İ'.to_lowercase());
/// ```
///
/// Both are equivalent to:
///
/// ```
/// println!("i\u{307}");
/// ```
///
/// Using `to_string`:
///
/// ```
/// assert_eq!('C'.to_lowercase().to_string(), "c");
///
/// // Sometimes the result is more than one character:
/// assert_eq!('İ'.to_lowercase().to_string(), "i\u{307}");
///
/// // Characters that do not have both uppercase and lowercase
/// // convert into themselves.
/// assert_eq!('山'.to_lowercase().to_string(), "山");
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn to_lowercase(self) -> ToLowercase {
ToLowercase(CaseMappingIter::new(conversions::to_lower(self)))
}
/// Returns an iterator that yields the uppercase mapping of this `char` as one or more
/// `char`s.
///
/// If this `char` does not have a uppercase mapping, the iterator yields the same `char`.
///
/// If this `char` has a one-to-one uppercase mapping given by the [Unicode Character
/// Database][ucd] [`UnicodeData.txt`], the iterator yields that `char`.
///
/// [ucd]: https://www.unicode.org/reports/tr44/
/// [`UnicodeData.txt`]: https://www.unicode.org/Public/UCD/latest/ucd/UnicodeData.txt
///
/// If this `char` requires special considerations (e.g. multiple `char`s) the iterator yields
/// the `char`(s) given by [`SpecialCasing.txt`].
///
/// [`SpecialCasing.txt`]: https://www.unicode.org/Public/UCD/latest/ucd/SpecialCasing.txt
///
/// This operation performs an unconditional mapping without tailoring. That is, the conversion
/// is independent of context and language.
///
/// In the [Unicode Standard], Chapter 4 (Character Properties) discusses case mapping in
/// general and Chapter 3 (Conformance) discusses the default algorithm for case conversion.
///
/// [Unicode Standard]: https://www.unicode.org/versions/latest/
///
/// # Examples
///
/// As an iterator:
///
/// ```
/// for c in 'ß'.to_uppercase() {
/// print!("{}", c);
/// }
/// println!();
/// ```
///
/// Using `println!` directly:
///
/// ```
/// println!("{}", 'ß'.to_uppercase());
/// ```
///
/// Both are equivalent to:
///
/// ```
/// println!("SS");
/// ```
///
/// Using `to_string`:
///
/// ```
/// assert_eq!('c'.to_uppercase().to_string(), "C");
///
/// // Sometimes the result is more than one character:
/// assert_eq!('ß'.to_uppercase().to_string(), "SS");
///
/// // Characters that do not have both uppercase and lowercase
/// // convert into themselves.
/// assert_eq!('山'.to_uppercase().to_string(), "山");
/// ```
///
/// # Note on locale
///
/// In Turkish, the equivalent of 'i' in Latin has five forms instead of two:
///
/// * 'Dotless': I / ı, sometimes written ï
/// * 'Dotted': İ / i
///
/// Note that the lowercase dotted 'i' is the same as the Latin. Therefore:
///
/// ```
/// let upper_i = 'i'.to_uppercase().to_string();
/// ```
///
/// The value of `upper_i` here relies on the language of the text: if we're
/// in `en-US`, it should be `"I"`, but if we're in `tr_TR`, it should
/// be `"İ"`. `to_uppercase()` does not take this into account, and so:
///
/// ```
/// let upper_i = 'i'.to_uppercase().to_string();
///
/// assert_eq!(upper_i, "I");
/// ```
///
/// holds across languages.
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn to_uppercase(self) -> ToUppercase {
ToUppercase(CaseMappingIter::new(conversions::to_upper(self)))
}
/// Checks if the value is within the ASCII range.
///
/// # Examples
///
/// ```
/// let ascii = 'a';
/// let non_ascii = '❤';
///
/// assert!(ascii.is_ascii());
/// assert!(!non_ascii.is_ascii());
/// ```
#[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
#[rustc_const_stable(feature = "const_ascii_methods_on_intrinsics", since = "1.32.0")]
#[inline]
pub const fn is_ascii(&self) -> bool {
*self as u32 <= 0x7F
}
/// 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
/// [`to_uppercase`].
///
/// # Examples
///
/// ```
/// let ascii = 'a';
/// let non_ascii = '❤';
///
/// assert_eq!('A', ascii.to_ascii_uppercase());
/// assert_eq!('❤', non_ascii.to_ascii_uppercase());
/// ```
///
/// [`make_ascii_uppercase`]: #method.make_ascii_uppercase
/// [`to_uppercase`]: #method.to_uppercase
#[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
#[inline]
pub fn to_ascii_uppercase(&self) -> char {
if self.is_ascii() { (*self as u8).to_ascii_uppercase() as char } else { *self }
}
/// 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
/// [`to_lowercase`].
///
/// # Examples
///
/// ```
/// let ascii = 'A';
/// let non_ascii = '❤';
///
/// assert_eq!('a', ascii.to_ascii_lowercase());
/// assert_eq!('❤', non_ascii.to_ascii_lowercase());
/// ```
///
/// [`make_ascii_lowercase`]: #method.make_ascii_lowercase
/// [`to_lowercase`]: #method.to_lowercase
#[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
#[inline]
pub fn to_ascii_lowercase(&self) -> char {
if self.is_ascii() { (*self as u8).to_ascii_lowercase() as char } else { *self }
}
/// Checks that two values are an ASCII case-insensitive match.
///
/// Equivalent to `to_ascii_lowercase(a) == to_ascii_lowercase(b)`.
///
/// # Examples
///
/// ```
/// let upper_a = 'A';
/// let lower_a = 'a';
/// let lower_z = 'z';
///
/// assert!(upper_a.eq_ignore_ascii_case(&lower_a));
/// assert!(upper_a.eq_ignore_ascii_case(&upper_a));
/// assert!(!upper_a.eq_ignore_ascii_case(&lower_z));
/// ```
#[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
#[inline]
pub fn eq_ignore_ascii_case(&self, other: &char) -> bool {
self.to_ascii_lowercase() == other.to_ascii_lowercase()
}
/// 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`].
///
/// # Examples
///
/// ```
/// let mut ascii = 'a';
///
/// ascii.make_ascii_uppercase();
///
/// assert_eq!('A', ascii);
/// ```
///
/// [`to_ascii_uppercase`]: #method.to_ascii_uppercase
#[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
#[inline]
pub fn make_ascii_uppercase(&mut self) {
*self = self.to_ascii_uppercase();
}
/// 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`].
///
/// # Examples
///
/// ```
/// let mut ascii = 'A';
///
/// ascii.make_ascii_lowercase();
///
/// assert_eq!('a', ascii);
/// ```
///
/// [`to_ascii_lowercase`]: #method.to_ascii_lowercase
#[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
#[inline]
pub fn make_ascii_lowercase(&mut self) {
*self = self.to_ascii_lowercase();
}
/// Checks if the value is an ASCII alphabetic character:
///
/// - U+0041 'A' ..= U+005A 'Z', or
/// - U+0061 'a' ..= U+007A 'z'.
///
/// # Examples
///
/// ```
/// let uppercase_a = 'A';
/// let uppercase_g = 'G';
/// let a = 'a';
/// let g = 'g';
/// let zero = '0';
/// let percent = '%';
/// let space = ' ';
/// let lf = '\n';
/// let esc: char = 0x1b_u8.into();
///
/// assert!(uppercase_a.is_ascii_alphabetic());
/// assert!(uppercase_g.is_ascii_alphabetic());
/// assert!(a.is_ascii_alphabetic());
/// assert!(g.is_ascii_alphabetic());
/// assert!(!zero.is_ascii_alphabetic());
/// assert!(!percent.is_ascii_alphabetic());
/// assert!(!space.is_ascii_alphabetic());
/// assert!(!lf.is_ascii_alphabetic());
/// assert!(!esc.is_ascii_alphabetic());
/// ```
#[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
#[inline]
pub fn is_ascii_alphabetic(&self) -> bool {
self.is_ascii() && (*self as u8).is_ascii_alphabetic()
}
/// Checks if the value is an ASCII uppercase character:
/// U+0041 'A' ..= U+005A 'Z'.
///
/// # Examples
///
/// ```
/// let uppercase_a = 'A';
/// let uppercase_g = 'G';
/// let a = 'a';
/// let g = 'g';
/// let zero = '0';
/// let percent = '%';
/// let space = ' ';
/// let lf = '\n';
/// let esc: char = 0x1b_u8.into();
///
/// assert!(uppercase_a.is_ascii_uppercase());
/// assert!(uppercase_g.is_ascii_uppercase());
/// assert!(!a.is_ascii_uppercase());
/// assert!(!g.is_ascii_uppercase());
/// assert!(!zero.is_ascii_uppercase());
/// assert!(!percent.is_ascii_uppercase());
/// assert!(!space.is_ascii_uppercase());
/// assert!(!lf.is_ascii_uppercase());
/// assert!(!esc.is_ascii_uppercase());
/// ```
#[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
#[inline]
pub fn is_ascii_uppercase(&self) -> bool {
self.is_ascii() && (*self as u8).is_ascii_uppercase()
}
/// Checks if the value is an ASCII lowercase character:
/// U+0061 'a' ..= U+007A 'z'.
///
/// # Examples
///
/// ```
/// let uppercase_a = 'A';
/// let uppercase_g = 'G';
/// let a = 'a';
/// let g = 'g';
/// let zero = '0';
/// let percent = '%';
/// let space = ' ';
/// let lf = '\n';
/// let esc: char = 0x1b_u8.into();
///
/// assert!(!uppercase_a.is_ascii_lowercase());
/// assert!(!uppercase_g.is_ascii_lowercase());
/// assert!(a.is_ascii_lowercase());
/// assert!(g.is_ascii_lowercase());
/// assert!(!zero.is_ascii_lowercase());
/// assert!(!percent.is_ascii_lowercase());
/// assert!(!space.is_ascii_lowercase());
/// assert!(!lf.is_ascii_lowercase());
/// assert!(!esc.is_ascii_lowercase());
/// ```
#[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
#[inline]
pub fn is_ascii_lowercase(&self) -> bool {
self.is_ascii() && (*self as u8).is_ascii_lowercase()
}
/// Checks if the value is an ASCII alphanumeric character:
///
/// - U+0041 'A' ..= U+005A 'Z', or
/// - U+0061 'a' ..= U+007A 'z', or
/// - U+0030 '0' ..= U+0039 '9'.
///
/// # Examples
///
/// ```
/// let uppercase_a = 'A';
/// let uppercase_g = 'G';
/// let a = 'a';
/// let g = 'g';
/// let zero = '0';
/// let percent = '%';
/// let space = ' ';
/// let lf = '\n';
/// let esc: char = 0x1b_u8.into();
///
/// assert!(uppercase_a.is_ascii_alphanumeric());
/// assert!(uppercase_g.is_ascii_alphanumeric());
/// assert!(a.is_ascii_alphanumeric());
/// assert!(g.is_ascii_alphanumeric());
/// assert!(zero.is_ascii_alphanumeric());
/// assert!(!percent.is_ascii_alphanumeric());
/// assert!(!space.is_ascii_alphanumeric());
/// assert!(!lf.is_ascii_alphanumeric());
/// assert!(!esc.is_ascii_alphanumeric());
/// ```
#[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
#[inline]
pub fn is_ascii_alphanumeric(&self) -> bool {
self.is_ascii() && (*self as u8).is_ascii_alphanumeric()
}
/// Checks if the value is an ASCII decimal digit:
/// U+0030 '0' ..= U+0039 '9'.
///
/// # Examples
///
/// ```
/// let uppercase_a = 'A';
/// let uppercase_g = 'G';
/// let a = 'a';
/// let g = 'g';
/// let zero = '0';
/// let percent = '%';
/// let space = ' ';
/// let lf = '\n';
/// let esc: char = 0x1b_u8.into();
///
/// assert!(!uppercase_a.is_ascii_digit());
/// assert!(!uppercase_g.is_ascii_digit());
/// assert!(!a.is_ascii_digit());
/// assert!(!g.is_ascii_digit());
/// assert!(zero.is_ascii_digit());
/// assert!(!percent.is_ascii_digit());
/// assert!(!space.is_ascii_digit());
/// assert!(!lf.is_ascii_digit());
/// assert!(!esc.is_ascii_digit());
/// ```
#[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
#[inline]
pub fn is_ascii_digit(&self) -> bool {
self.is_ascii() && (*self as u8).is_ascii_digit()
}
/// Checks if the value is an ASCII hexadecimal digit:
///
/// - U+0030 '0' ..= U+0039 '9', or
/// - U+0041 'A' ..= U+0046 'F', or
/// - U+0061 'a' ..= U+0066 'f'.
///
/// # Examples
///
/// ```
/// let uppercase_a = 'A';
/// let uppercase_g = 'G';
/// let a = 'a';
/// let g = 'g';
/// let zero = '0';
/// let percent = '%';
/// let space = ' ';
/// let lf = '\n';
/// let esc: char = 0x1b_u8.into();
///
/// assert!(uppercase_a.is_ascii_hexdigit());
/// assert!(!uppercase_g.is_ascii_hexdigit());
/// assert!(a.is_ascii_hexdigit());
/// assert!(!g.is_ascii_hexdigit());
/// assert!(zero.is_ascii_hexdigit());
/// assert!(!percent.is_ascii_hexdigit());
/// assert!(!space.is_ascii_hexdigit());
/// assert!(!lf.is_ascii_hexdigit());
/// assert!(!esc.is_ascii_hexdigit());
/// ```
#[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
#[inline]
pub fn is_ascii_hexdigit(&self) -> bool {
self.is_ascii() && (*self as u8).is_ascii_hexdigit()
}
/// Checks if the value is an ASCII punctuation character:
///
/// - U+0021 ..= U+002F `! " # $ % & ' ( ) * + , - . /`, or
/// - U+003A ..= U+0040 `: ; < = > ? @`, or
/// - U+005B ..= U+0060 ``[ \ ] ^ _ ` ``, or
/// - U+007B ..= U+007E `{ | } ~`
///
/// # Examples
///
/// ```
/// let uppercase_a = 'A';
/// let uppercase_g = 'G';
/// let a = 'a';
/// let g = 'g';
/// let zero = '0';
/// let percent = '%';
/// let space = ' ';
/// let lf = '\n';
/// let esc: char = 0x1b_u8.into();
///
/// assert!(!uppercase_a.is_ascii_punctuation());
/// assert!(!uppercase_g.is_ascii_punctuation());
/// assert!(!a.is_ascii_punctuation());
/// assert!(!g.is_ascii_punctuation());
/// assert!(!zero.is_ascii_punctuation());
/// assert!(percent.is_ascii_punctuation());
/// assert!(!space.is_ascii_punctuation());
/// assert!(!lf.is_ascii_punctuation());
/// assert!(!esc.is_ascii_punctuation());
/// ```
#[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
#[inline]
pub fn is_ascii_punctuation(&self) -> bool {
self.is_ascii() && (*self as u8).is_ascii_punctuation()
}
/// Checks if the value is an ASCII graphic character:
/// U+0021 '!' ..= U+007E '~'.
///
/// # Examples
///
/// ```
/// let uppercase_a = 'A';
/// let uppercase_g = 'G';
/// let a = 'a';
/// let g = 'g';
/// let zero = '0';
/// let percent = '%';
/// let space = ' ';
/// let lf = '\n';
/// let esc: char = 0x1b_u8.into();
///
/// assert!(uppercase_a.is_ascii_graphic());
/// assert!(uppercase_g.is_ascii_graphic());
/// assert!(a.is_ascii_graphic());
/// assert!(g.is_ascii_graphic());
/// assert!(zero.is_ascii_graphic());
/// assert!(percent.is_ascii_graphic());
/// assert!(!space.is_ascii_graphic());
/// assert!(!lf.is_ascii_graphic());
/// assert!(!esc.is_ascii_graphic());
/// ```
#[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
#[inline]
pub fn is_ascii_graphic(&self) -> bool {
self.is_ascii() && (*self as u8).is_ascii_graphic()
}
/// Checks if the value is an ASCII whitespace character:
/// U+0020 SPACE, U+0009 HORIZONTAL TAB, U+000A LINE FEED,
/// U+000C FORM FEED, or U+000D CARRIAGE RETURN.
///
/// Rust uses the WhatWG Infra Standard's [definition of ASCII
/// whitespace][infra-aw]. There are several other definitions in
/// wide use. For instance, [the POSIX locale][pct] includes
/// U+000B VERTICAL TAB as well as all the above characters,
/// but—from the very same specification—[the default rule for
/// "field splitting" in the Bourne shell][bfs] considers *only*
/// SPACE, HORIZONTAL TAB, and LINE FEED as whitespace.
///
/// If you are writing a program that will process an existing
/// file format, check what that format's definition of whitespace is
/// before using this function.
///
/// [infra-aw]: https://infra.spec.whatwg.org/#ascii-whitespace
/// [pct]: http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap07.html#tag_07_03_01
/// [bfs]: http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_05
///
/// # Examples
///
/// ```
/// let uppercase_a = 'A';
/// let uppercase_g = 'G';
/// let a = 'a';
/// let g = 'g';
/// let zero = '0';
/// let percent = '%';
/// let space = ' ';
/// let lf = '\n';
/// let esc: char = 0x1b_u8.into();
///
/// assert!(!uppercase_a.is_ascii_whitespace());
/// assert!(!uppercase_g.is_ascii_whitespace());
/// assert!(!a.is_ascii_whitespace());
/// assert!(!g.is_ascii_whitespace());
/// assert!(!zero.is_ascii_whitespace());
/// assert!(!percent.is_ascii_whitespace());
/// assert!(space.is_ascii_whitespace());
/// assert!(lf.is_ascii_whitespace());
/// assert!(!esc.is_ascii_whitespace());
/// ```
#[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
#[inline]
pub fn is_ascii_whitespace(&self) -> bool {
self.is_ascii() && (*self as u8).is_ascii_whitespace()
}
/// Checks if the value is an ASCII control character:
/// U+0000 NUL ..= U+001F UNIT SEPARATOR, or U+007F DELETE.
/// Note that most ASCII whitespace characters are control
/// characters, but SPACE is not.
///
/// # Examples
///
/// ```
/// let uppercase_a = 'A';
/// let uppercase_g = 'G';
/// let a = 'a';
/// let g = 'g';
/// let zero = '0';
/// let percent = '%';
/// let space = ' ';
/// let lf = '\n';
/// let esc: char = 0x1b_u8.into();
///
/// assert!(!uppercase_a.is_ascii_control());
/// assert!(!uppercase_g.is_ascii_control());
/// assert!(!a.is_ascii_control());
/// assert!(!g.is_ascii_control());
/// assert!(!zero.is_ascii_control());
/// assert!(!percent.is_ascii_control());
/// assert!(!space.is_ascii_control());
/// assert!(lf.is_ascii_control());
/// assert!(esc.is_ascii_control());
/// ```
#[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
#[inline]
pub fn is_ascii_control(&self) -> bool {
self.is_ascii() && (*self as u8).is_ascii_control()
}
}