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author | Valentin Popov <valentin@popov.link> | 2024-01-08 00:21:28 +0300 |
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committer | Valentin Popov <valentin@popov.link> | 2024-01-08 00:21:28 +0300 |
commit | 1b6a04ca5504955c571d1c97504fb45ea0befee4 (patch) | |
tree | 7579f518b23313e8a9748a88ab6173d5e030b227 /vendor/encode_unicode/src/utf8_char.rs | |
parent | 5ecd8cf2cba827454317368b68571df0d13d7842 (diff) | |
download | fparkan-1b6a04ca5504955c571d1c97504fb45ea0befee4.tar.xz fparkan-1b6a04ca5504955c571d1c97504fb45ea0befee4.zip |
Initial vendor packages
Signed-off-by: Valentin Popov <valentin@popov.link>
Diffstat (limited to 'vendor/encode_unicode/src/utf8_char.rs')
-rw-r--r-- | vendor/encode_unicode/src/utf8_char.rs | 647 |
1 files changed, 647 insertions, 0 deletions
diff --git a/vendor/encode_unicode/src/utf8_char.rs b/vendor/encode_unicode/src/utf8_char.rs new file mode 100644 index 0000000..9dba4ba --- /dev/null +++ b/vendor/encode_unicode/src/utf8_char.rs @@ -0,0 +1,647 @@ +/* Copyright 2016 The encode_unicode Developers + * + * Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or + * http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or + * http://opensource.org/licenses/MIT>, at your option. This file may not be + * copied, modified, or distributed except according to those terms. + */ + +use errors::{FromStrError, EmptyStrError, NonAsciiError, InvalidUtf8Slice, InvalidUtf8Array}; +use utf8_iterators::Utf8Iterator; +use traits::{CharExt, U8UtfExt}; +use utf16_char::Utf16Char; +extern crate core; +use self::core::{hash, fmt, str, ptr}; +use self::core::cmp::Ordering; +use self::core::borrow::Borrow; +use self::core::ops::Deref; +use self::core::mem::transmute; +#[cfg(feature="std")] +use self::core::iter::FromIterator; +#[cfg(feature="std")] +#[allow(deprecated)] +use std::ascii::AsciiExt; +#[cfg(feature="ascii")] +extern crate ascii; +#[cfg(feature="ascii")] +use self::ascii::{AsciiChar,ToAsciiChar,ToAsciiCharError}; + + +// I don't think there is any good default value for char, but char does. +#[derive(Default)] +// char doesn't do anything more advanced than u32 for Eq/Ord, so we shouldn't either. +// The default impl of Ord for arrays works out because longer codepoints +// start with more ones, so if they're equal, the length is the same, +// breaks down for values above 0x1f_ff_ff but those can only be created by unsafe code. +#[derive(PartialEq,Eq, PartialOrd,Ord)] + +#[derive(Clone,Copy)] + + +/// An unicode codepoint stored as UTF-8. +/// +/// It can be borrowed as a `str`, and has the same size as `char`. +pub struct Utf8Char { + bytes: [u8; 4], +} + + + ///////////////////// + //conversion traits// +///////////////////// +impl str::FromStr for Utf8Char { + type Err = FromStrError; + /// Create an `Utf8Char` from a string slice. + /// The string must contain exactly one codepoint. + /// + /// # Examples + /// + /// ``` + /// use encode_unicode::error::FromStrError::*; + /// use encode_unicode::Utf8Char; + /// use std::str::FromStr; + /// + /// assert_eq!(Utf8Char::from_str("a"), Ok(Utf8Char::from('a'))); + /// assert_eq!(Utf8Char::from_str("🂠"), Ok(Utf8Char::from('🂠'))); + /// assert_eq!(Utf8Char::from_str(""), Err(Empty)); + /// assert_eq!(Utf8Char::from_str("ab"), Err(MultipleCodepoints)); + /// assert_eq!(Utf8Char::from_str("é"), Err(MultipleCodepoints));// 'e'+u301 combining mark + /// ``` + fn from_str(s: &str) -> Result<Self, FromStrError> { + if s.is_empty() { + Err(FromStrError::Empty) + } else if s.len() != 1+s.as_bytes()[0].extra_utf8_bytes_unchecked() { + Err(FromStrError::MultipleCodepoints) + } else { + let mut bytes = [0; 4]; + bytes[..s.len()].copy_from_slice(s.as_bytes()); + Ok(Utf8Char{bytes: bytes}) + } + } +} +impl From<Utf16Char> for Utf8Char { + fn from(utf16: Utf16Char) -> Utf8Char { + match utf16.to_tuple() { + (a @ 0...0x00_7f, _) => { + Utf8Char{ bytes: [a as u8, 0, 0, 0] } + }, + (u @ 0...0x07_ff, _) => { + let b = 0x80 | (u & 0x00_3f) as u8; + let a = 0xc0 | ((u & 0x07_c0) >> 6) as u8; + Utf8Char{ bytes: [a, b, 0, 0] } + }, + (u, None) => { + let c = 0x80 | (u & 0x00_3f) as u8; + let b = 0x80 | ((u & 0x0f_c0) >> 6) as u8; + let a = 0xe0 | ((u & 0xf0_00) >> 12) as u8; + Utf8Char{ bytes: [a, b, c, 0] } + }, + (f, Some(s)) => { + let f = f + (0x01_00_00u32 >> 10) as u16; + let d = 0x80 | (s & 0x00_3f) as u8; + let c = 0x80 | ((s & 0x03_c0) >> 6) as u8 + | ((f & 0x00_03) << 4) as u8; + let b = 0x80 | ((f & 0x00_fc) >> 2) as u8; + let a = 0xf0 | ((f & 0x07_00) >> 8) as u8; + Utf8Char{ bytes: [a, b, c, d] } + } + } + } +} +impl From<char> for Utf8Char { + fn from(c: char) -> Self { + Utf8Char{ bytes: c.to_utf8_array().0 } + } +} +impl From<Utf8Char> for char { + fn from(uc: Utf8Char) -> char { + unsafe{ char::from_utf8_exact_slice_unchecked(&uc.bytes[..uc.len()]) } + } +} +impl IntoIterator for Utf8Char { + type Item=u8; + type IntoIter=Utf8Iterator; + /// Iterate over the byte values. + fn into_iter(self) -> Utf8Iterator { + Utf8Iterator::from(self) + } +} + +#[cfg(feature="std")] +impl Extend<Utf8Char> for Vec<u8> { + fn extend<I:IntoIterator<Item=Utf8Char>>(&mut self, iter: I) { + let iter = iter.into_iter(); + self.reserve(iter.size_hint().0); + for u8c in iter { + // twice as fast as self.extend_from_slice(u8c.as_bytes()); + self.push(u8c.bytes[0]); + for &extra in &u8c.bytes[1..] { + if extra != 0 { + self.push(extra); + } + } + } + } +} +#[cfg(feature="std")] +impl<'a> Extend<&'a Utf8Char> for Vec<u8> { + fn extend<I:IntoIterator<Item=&'a Utf8Char>>(&mut self, iter: I) { + self.extend(iter.into_iter().cloned()) + } +} +#[cfg(feature="std")] +impl Extend<Utf8Char> for String { + fn extend<I:IntoIterator<Item=Utf8Char>>(&mut self, iter: I) { + unsafe { self.as_mut_vec().extend(iter) } + } +} +#[cfg(feature="std")] +impl<'a> Extend<&'a Utf8Char> for String { + fn extend<I:IntoIterator<Item=&'a Utf8Char>>(&mut self, iter: I) { + self.extend(iter.into_iter().cloned()) + } +} +#[cfg(feature="std")] +impl FromIterator<Utf8Char> for String { + fn from_iter<I:IntoIterator<Item=Utf8Char>>(iter: I) -> String { + let mut string = String::new(); + string.extend(iter); + return string; + } +} +#[cfg(feature="std")] +impl<'a> FromIterator<&'a Utf8Char> for String { + fn from_iter<I:IntoIterator<Item=&'a Utf8Char>>(iter: I) -> String { + iter.into_iter().cloned().collect() + } +} +#[cfg(feature="std")] +impl FromIterator<Utf8Char> for Vec<u8> { + fn from_iter<I:IntoIterator<Item=Utf8Char>>(iter: I) -> Self { + iter.into_iter().collect::<String>().into_bytes() + } +} +#[cfg(feature="std")] +impl<'a> FromIterator<&'a Utf8Char> for Vec<u8> { + fn from_iter<I:IntoIterator<Item=&'a Utf8Char>>(iter: I) -> Self { + iter.into_iter().cloned().collect::<String>().into_bytes() + } +} + + + ///////////////// + //getter traits// +///////////////// +impl AsRef<[u8]> for Utf8Char { + fn as_ref(&self) -> &[u8] { + &self.bytes[..self.len()] + } +} +impl AsRef<str> for Utf8Char { + fn as_ref(&self) -> &str { + unsafe{ str::from_utf8_unchecked( self.as_ref() ) } + } +} +impl Borrow<[u8]> for Utf8Char { + fn borrow(&self) -> &[u8] { + self.as_ref() + } +} +impl Borrow<str> for Utf8Char { + fn borrow(&self) -> &str { + self.as_ref() + } +} +impl Deref for Utf8Char { + type Target = str; + fn deref(&self) -> &Self::Target { + self.as_ref() + } +} + + + //////////////// + //ascii traits// +//////////////// +#[cfg(feature="std")] +#[allow(deprecated)] +impl AsciiExt for Utf8Char { + type Owned = Utf8Char; + fn is_ascii(&self) -> bool { + self.bytes[0].is_ascii() + } + fn eq_ignore_ascii_case(&self, other: &Self) -> bool { + if self.is_ascii() {self.bytes[0].eq_ignore_ascii_case(&other.bytes[0])} + else {self == other} + } + fn to_ascii_uppercase(&self) -> Self::Owned { + let mut uc = *self; + uc.make_ascii_uppercase(); + uc + } + fn to_ascii_lowercase(&self) -> Self::Owned { + let mut uc = *self; + uc.make_ascii_lowercase(); + uc + } + fn make_ascii_uppercase(&mut self) { + self.bytes[0].make_ascii_uppercase() + } + fn make_ascii_lowercase(&mut self) { + self.bytes[0].make_ascii_lowercase(); + } +} + +#[cfg(feature="ascii")] +/// Requires the feature "ascii". +impl From<AsciiChar> for Utf8Char { + fn from(ac: AsciiChar) -> Self { + Utf8Char{ bytes: [ac.as_byte(),0,0,0] } + } +} +#[cfg(feature="ascii")] +/// Requires the feature "ascii". +impl ToAsciiChar for Utf8Char { + fn to_ascii_char(self) -> Result<AsciiChar, ToAsciiCharError> { + self.bytes[0].to_ascii_char() + } + unsafe fn to_ascii_char_unchecked(self) -> AsciiChar { + self.bytes[0].to_ascii_char_unchecked() + } +} + + + ///////////////////////////////////////////////////////// + //Genaral traits that cannot be derived to emulate char// +///////////////////////////////////////////////////////// +impl hash::Hash for Utf8Char { + fn hash<H : hash::Hasher>(&self, state: &mut H) { + self.to_char().hash(state); + } +} +impl fmt::Debug for Utf8Char { + fn fmt(&self, fmtr: &mut fmt::Formatter) -> fmt::Result { + fmt::Debug::fmt(&self.to_char(), fmtr) + } +} +impl fmt::Display for Utf8Char { + fn fmt(&self, fmtr: &mut fmt::Formatter) -> fmt::Result { + fmtr.write_str(self.as_str()) + } +} + + + //////////////////////////////// + //Comparisons with other types// +//////////////////////////////// +impl PartialEq<char> for Utf8Char { + fn eq(&self, u32c: &char) -> bool { + *self == Utf8Char::from(*u32c) + } +} +impl PartialEq<Utf8Char> for char { + fn eq(&self, u8c: &Utf8Char) -> bool { + Utf8Char::from(*self) == *u8c + } +} +impl PartialOrd<char> for Utf8Char { + fn partial_cmp(&self, u32c: &char) -> Option<Ordering> { + self.partial_cmp(&Self::from(*u32c)) + } +} +impl PartialOrd<Utf8Char> for char { + fn partial_cmp(&self, u8c: &Utf8Char) -> Option<Ordering> { + Utf8Char::from(*self).partial_cmp(u8c) + } +} + +impl PartialEq<Utf16Char> for Utf8Char { + fn eq(&self, u16c: &Utf16Char) -> bool { + *self == Self::from(*u16c) + } +} +impl PartialOrd<Utf16Char> for Utf8Char { + fn partial_cmp(&self, u16c: &Utf16Char) -> Option<Ordering> { + self.partial_cmp(&Self::from(*u16c)) + } +} +// The other direction is implemented in utf16_char.rs + +/// Only considers the byte equal if both it and the `Utf8Char` represents ASCII characters. +/// +/// There is no impl in the opposite direction, as this should only be used to +/// compare `Utf8Char`s against constants. +/// +/// # Examples +/// +/// ``` +/// # use encode_unicode::Utf8Char; +/// assert!(Utf8Char::from('8') == b'8'); +/// assert!(Utf8Char::from_array([0xf1,0x80,0x80,0x80]).unwrap() != 0xf1); +/// assert!(Utf8Char::from('\u{ff}') != 0xff); +/// assert!(Utf8Char::from('\u{80}') != 0x80); +/// ``` +impl PartialEq<u8> for Utf8Char { + fn eq(&self, byte: &u8) -> bool { + self.bytes[0] == *byte && self.bytes[1] == 0 + } +} +#[cfg(feature = "ascii")] +/// `Utf8Char`s that are not ASCII never compare equal. +impl PartialEq<AsciiChar> for Utf8Char { + #[inline] + fn eq(&self, ascii: &AsciiChar) -> bool { + self.bytes[0] == *ascii as u8 + } +} +#[cfg(feature = "ascii")] +/// `Utf8Char`s that are not ASCII never compare equal. +impl PartialEq<Utf8Char> for AsciiChar { + #[inline] + fn eq(&self, u8c: &Utf8Char) -> bool { + u8c == self + } +} +#[cfg(feature = "ascii")] +/// `Utf8Char`s that are not ASCII always compare greater. +impl PartialOrd<AsciiChar> for Utf8Char { + #[inline] + fn partial_cmp(&self, ascii: &AsciiChar) -> Option<Ordering> { + self.bytes[0].partial_cmp(ascii) + } +} +#[cfg(feature = "ascii")] +/// `Utf8Char`s that are not ASCII always compare greater. +impl PartialOrd<Utf8Char> for AsciiChar { + #[inline] + fn partial_cmp(&self, u8c: &Utf8Char) -> Option<Ordering> { + self.partial_cmp(&u8c.bytes[0]) + } +} + + + /////////////////////////////////////////////////////// + //pub impls that should be together for nicer rustdoc// +/////////////////////////////////////////////////////// +impl Utf8Char { + /// Create an `Utf8Char` from the first codepoint in a `str`. + /// + /// Returns an error if the `str` is empty. + /// + /// # Examples + /// + /// ``` + /// use encode_unicode::Utf8Char; + /// + /// assert_eq!(Utf8Char::from_str_start("a"), Ok((Utf8Char::from('a'),1))); + /// assert_eq!(Utf8Char::from_str_start("ab"), Ok((Utf8Char::from('a'),1))); + /// assert_eq!(Utf8Char::from_str_start("🂠 "), Ok((Utf8Char::from('🂠'),4))); + /// assert_eq!(Utf8Char::from_str_start("é"), Ok((Utf8Char::from('e'),1)));// 'e'+u301 combining mark + /// assert!(Utf8Char::from_str_start("").is_err()); + /// ``` + pub fn from_str_start(src: &str) -> Result<(Self,usize),EmptyStrError> { + unsafe { + if src.is_empty() { + Err(EmptyStrError) + } else { + Ok(Utf8Char::from_slice_start_unchecked(src.as_bytes())) + } + } + } + /// Create an `Utf8Char` of the first codepoint in an UTF-8 slice. + /// Also returns the length of the UTF-8 sequence for the codepoint. + /// + /// If the slice is from a `str`, use `::from_str_start()` to skip UTF-8 validation. + /// + /// # Errors + /// + /// Returns an `Err` if the slice is empty, doesn't start with a valid + /// UTF-8 sequence or is too short for the sequence. + /// + /// # Examples + /// + /// ``` + /// use encode_unicode::Utf8Char; + /// use encode_unicode::error::InvalidUtf8Slice::*; + /// use encode_unicode::error::InvalidUtf8::*; + /// + /// assert_eq!(Utf8Char::from_slice_start(&[b'A', b'B', b'C']), Ok((Utf8Char::from('A'),1))); + /// assert_eq!(Utf8Char::from_slice_start(&[0xdd, 0xbb]), Ok((Utf8Char::from('\u{77b}'),2))); + /// + /// assert_eq!(Utf8Char::from_slice_start(&[]), Err(TooShort(1))); + /// assert_eq!(Utf8Char::from_slice_start(&[0xf0, 0x99]), Err(TooShort(4))); + /// assert_eq!(Utf8Char::from_slice_start(&[0xee, b'F', 0x80]), Err(Utf8(NotAContinuationByte(1)))); + /// assert_eq!(Utf8Char::from_slice_start(&[0xee, 0x99, 0x0f]), Err(Utf8(NotAContinuationByte(2)))); + /// ``` + pub fn from_slice_start(src: &[u8]) -> Result<(Self,usize),InvalidUtf8Slice> { + char::from_utf8_slice_start(src).map(|(_,len)| { + let mut bytes = [0; 4]; + bytes[..len].copy_from_slice(&src[..len]); + (Utf8Char{ bytes: bytes }, len) + }) + } + /// A `from_slice_start()` that doesn't validate the codepoint. + /// + /// # Safety + /// + /// The slice must be non-empty and start with a valid UTF-8 codepoint. + /// Invalid or incomplete values might cause reads of uninitalized memory. + pub unsafe fn from_slice_start_unchecked(src: &[u8]) -> (Self,usize) { + let len = 1+src.get_unchecked(0).extra_utf8_bytes_unchecked(); + let mut bytes = [0; 4]; + ptr::copy_nonoverlapping(src.as_ptr(), &mut bytes[0] as *mut u8, len); + (Utf8Char{ bytes: bytes }, len) + } + /// Create an `Utf8Char` from a byte array after validating it. + /// + /// The codepoint must start at the first byte. + /// Unused bytes are set to zero by this function and so can be anything. + /// + /// # Errors + /// + /// Returns an `Err` if the array doesn't start with a valid UTF-8 sequence. + /// + /// # Examples + /// + /// ``` + /// use encode_unicode::Utf8Char; + /// use encode_unicode::error::InvalidUtf8Array::*; + /// use encode_unicode::error::InvalidUtf8::*; + /// use encode_unicode::error::InvalidCodepoint::*; + /// + /// assert_eq!(Utf8Char::from_array([b'A', 0, 0, 0]), Ok(Utf8Char::from('A'))); + /// assert_eq!(Utf8Char::from_array([0xf4, 0x8b, 0xbb, 0xbb]), Ok(Utf8Char::from('\u{10befb}'))); + /// assert_eq!(Utf8Char::from_array([b'A', b'B', b'C', b'D']), Ok(Utf8Char::from('A'))); + /// assert_eq!(Utf8Char::from_array([0, 0, 0xcc, 0xbb]), Ok(Utf8Char::from('\0'))); + /// + /// assert_eq!(Utf8Char::from_array([0xef, b'F', 0x80, 0x80]), Err(Utf8(NotAContinuationByte(1)))); + /// assert_eq!(Utf8Char::from_array([0xc1, 0x80, 0, 0]), Err(Utf8(OverLong))); + /// assert_eq!(Utf8Char::from_array([0xf7, 0xaa, 0x99, 0x88]), Err(Codepoint(TooHigh))); + /// ``` + pub fn from_array(utf8: [u8;4]) -> Result<Self,InvalidUtf8Array> { + unsafe { + // perform all validation + try!(char::from_utf8_array(utf8)); + let extra = utf8[0].extra_utf8_bytes_unchecked() as u32; + // zero unused bytes in one operation by transmuting the arrary to + // u32, apply an endian-corrected mask and transmute back + let mask = u32::from_le(0xff_ff_ff_ff >> 8*(3-extra)); + let unused_zeroed = mask & transmute::<_,u32>(utf8); + Ok(Utf8Char{ bytes: transmute(unused_zeroed) }) + } + } + /// Zero-cost constructor. + /// + /// # Safety + /// + /// Must contain a valid codepoint starting at the first byte, with the + /// unused bytes zeroed. + /// Bad values can easily lead to undefined behavior. + #[inline] + pub unsafe fn from_array_unchecked(utf8: [u8;4]) -> Self { + Utf8Char{ bytes: utf8 } + } + /// Create an `Utf8Char` from a single byte. + /// + /// The byte must be an ASCII character. + /// + /// # Errors + /// + /// Returns `NonAsciiError` if the byte greater than 127. + /// + /// # Examples + /// + /// ``` + /// # use encode_unicode::Utf8Char; + /// assert_eq!(Utf8Char::from_ascii(b'a').unwrap(), 'a'); + /// assert!(Utf8Char::from_ascii(128).is_err()); + /// ``` + pub fn from_ascii(ascii: u8) -> Result<Self,NonAsciiError> { + if ascii as i8 >= 0 { + Ok(Utf8Char{ bytes: [ascii, 0, 0, 0] }) + } else { + Err(NonAsciiError) + } + } + /// Create an `Utf8Char` from a single byte without checking that it's a + /// valid codepoint on its own, which is only true for ASCII characters. + /// + /// # Safety + /// + /// The byte must be less than 128. + #[inline] + pub unsafe fn from_ascii_unchecked(ascii: u8) -> Self { + Utf8Char{ bytes: [ascii, 0, 0, 0] } + } + + /// The number of bytes this character needs. + /// + /// Is between 1 and 4 (inclusive) and identical to `.as_ref().len()` or + /// `.as_char().len_utf8()`. + #[inline] + pub fn len(self) -> usize { + // Invariants of the extra bytes enambles algorithms that + // `u8.extra_utf8_bytes_unchecked()` cannot use. + // Some of them turned out to require fewer x86 instructions: + + // Exploits that unused bytes are zero and calculates the number of + // trailing zero bytes. + // Setting a bit in the first byte prevents the function from returning + // 0 for '\0' (which has 32 leading zeros). + // trailing and leading is swapped below to optimize for little-endian + // architectures. + (4 - (u32::to_le(unsafe{transmute(self.bytes)})|1).leading_zeros()/8) as usize + + // Exploits that the extra bytes have their most significant bit set if + // in use. + // Takes fewer instructions than the one above if popcnt can be used, + // (which it cannot by default, + // set RUSTFLAGS='-C target-cpu=native' to enable) + //let all: u32 = unsafe{transmute(self.bytes)}; + //let msb_mask = u32::from_be(0x00808080); + //let add_one = u32::from_be(0x80000000); + //((all & msb_mask) | add_one).count_ones() as usize + } + // There is no .is_emty() because this type is never empty. + + /// Checks that the codepoint is an ASCII character. + pub fn is_ascii(&self) -> bool { + self.bytes[0] <= 127 + } + /// Checks that two characters are an ASCII case-insensitive match. + /// + /// Is equivalent to `a.to_ascii_lowercase() == b.to_ascii_lowercase()`. + #[cfg(feature="std")] + pub fn eq_ignore_ascii_case(&self, other: &Self) -> bool { + if self.is_ascii() {self.bytes[0].eq_ignore_ascii_case(&other.bytes[0])} + else {self == other} + } + /// Converts the character to its ASCII upper case equivalent. + /// + /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z', + /// but non-ASCII letters are unchanged. + #[cfg(feature="std")] + pub fn to_ascii_uppercase(&self) -> Self { + let mut uc = *self; + uc.make_ascii_uppercase(); + uc + } + /// Converts the character to its ASCII lower case equivalent. + /// + /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z', + /// but non-ASCII letters are unchanged. + #[cfg(feature="std")] + pub fn to_ascii_lowercase(&self) -> Self { + let mut uc = *self; + uc.make_ascii_lowercase(); + uc + } + /// Converts the character 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. + #[inline] + #[cfg(feature="std")] + pub fn make_ascii_uppercase(&mut self) { + self.bytes[0].make_ascii_uppercase() + } + /// Converts the character 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. + #[inline] + #[cfg(feature="std")] + pub fn make_ascii_lowercase(&mut self) { + self.bytes[0].make_ascii_lowercase(); + } + + /// Convert from UTF-8 to UTF-32 + pub fn to_char(self) -> char { + self.into() + } + /// Write the internal representation to a slice, + /// and then returns the number of bytes written. + /// + /// # Panics + /// + /// Will panic the buffer is too small; + /// You can get the required length from `.len()`, + /// but a buffer of length four is always large enough. + pub fn to_slice(self, dst: &mut[u8]) -> usize { + if self.len() > dst.len() { + panic!("The provided buffer is too small."); + } + dst[..self.len()].copy_from_slice(&self.bytes[..self.len()]); + self.len() + } + /// Expose the internal array and the number of used bytes. + pub fn to_array(self) -> ([u8;4],usize) { + (self.bytes, self.len()) + } + /// Return a `str` view of the array the codepoint is stored as. + /// + /// Is an unambiguous version of `.as_ref()`. + pub fn as_str(&self) -> &str { + self.deref() + } +} |