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Copy WTF-8 code into core/alloc (for better diffs)
This commit is contained in:
ltdk
@@ -0,0 +1,1083 @@
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//! Implementation of [the WTF-8 encoding](https://simonsapin.github.io/wtf-8/).
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//!
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//! This library uses Rust’s type system to maintain
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//! [well-formedness](https://simonsapin.github.io/wtf-8/#well-formed),
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//! like the `String` and `&str` types do for UTF-8.
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//!
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//! Since [WTF-8 must not be used
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//! for interchange](https://simonsapin.github.io/wtf-8/#intended-audience),
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//! this library deliberately does not provide access to the underlying bytes
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//! of WTF-8 strings,
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//! nor can it decode WTF-8 from arbitrary bytes.
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//! WTF-8 strings can be obtained from UTF-8, UTF-16, or code points.
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// this module is imported from @SimonSapin's repo and has tons of dead code on
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// unix (it's mostly used on windows), so don't worry about dead code here.
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#![allow(dead_code)]
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#[cfg(test)]
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mod tests;
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use core::char::{MAX_LEN_UTF8, MAX_LEN_UTF16, encode_utf8_raw, encode_utf16_raw};
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use core::clone::CloneToUninit;
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use core::str::next_code_point;
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use crate::borrow::Cow;
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use crate::collections::TryReserveError;
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use crate::hash::{Hash, Hasher};
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use crate::iter::FusedIterator;
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use crate::rc::Rc;
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use crate::sync::Arc;
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use crate::sys_common::AsInner;
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use crate::{fmt, mem, ops, slice, str};
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const UTF8_REPLACEMENT_CHARACTER: &str = "\u{FFFD}";
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/// A Unicode code point: from U+0000 to U+10FFFF.
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///
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/// Compares with the `char` type,
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/// which represents a Unicode scalar value:
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/// a code point that is not a surrogate (U+D800 to U+DFFF).
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#[derive(Eq, PartialEq, Ord, PartialOrd, Clone, Copy)]
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pub struct CodePoint {
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value: u32,
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}
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/// Format the code point as `U+` followed by four to six hexadecimal digits.
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/// Example: `U+1F4A9`
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impl fmt::Debug for CodePoint {
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#[inline]
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fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
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write!(formatter, "U+{:04X}", self.value)
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}
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}
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impl CodePoint {
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/// Unsafely creates a new `CodePoint` without checking the value.
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///
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/// Only use when `value` is known to be less than or equal to 0x10FFFF.
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#[inline]
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pub unsafe fn from_u32_unchecked(value: u32) -> CodePoint {
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CodePoint { value }
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}
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/// Creates a new `CodePoint` if the value is a valid code point.
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///
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/// Returns `None` if `value` is above 0x10FFFF.
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#[inline]
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pub fn from_u32(value: u32) -> Option<CodePoint> {
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match value {
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0..=0x10FFFF => Some(CodePoint { value }),
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_ => None,
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}
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}
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/// Creates a new `CodePoint` from a `char`.
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///
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/// Since all Unicode scalar values are code points, this always succeeds.
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#[inline]
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pub fn from_char(value: char) -> CodePoint {
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CodePoint { value: value as u32 }
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}
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/// Returns the numeric value of the code point.
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#[inline]
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pub fn to_u32(&self) -> u32 {
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self.value
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}
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/// Returns the numeric value of the code point if it is a leading surrogate.
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#[inline]
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pub fn to_lead_surrogate(&self) -> Option<u16> {
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match self.value {
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lead @ 0xD800..=0xDBFF => Some(lead as u16),
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_ => None,
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}
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}
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/// Returns the numeric value of the code point if it is a trailing surrogate.
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#[inline]
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pub fn to_trail_surrogate(&self) -> Option<u16> {
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match self.value {
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trail @ 0xDC00..=0xDFFF => Some(trail as u16),
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_ => None,
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}
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}
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/// Optionally returns a Unicode scalar value for the code point.
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///
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/// Returns `None` if the code point is a surrogate (from U+D800 to U+DFFF).
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#[inline]
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pub fn to_char(&self) -> Option<char> {
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match self.value {
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0xD800..=0xDFFF => None,
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_ => Some(unsafe { char::from_u32_unchecked(self.value) }),
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}
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}
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/// Returns a Unicode scalar value for the code point.
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///
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/// Returns `'\u{FFFD}'` (the replacement character “�”)
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/// if the code point is a surrogate (from U+D800 to U+DFFF).
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#[inline]
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pub fn to_char_lossy(&self) -> char {
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self.to_char().unwrap_or('\u{FFFD}')
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}
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}
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/// An owned, growable string of well-formed WTF-8 data.
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///
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/// Similar to `String`, but can additionally contain surrogate code points
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/// if they’re not in a surrogate pair.
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#[derive(Eq, PartialEq, Ord, PartialOrd, Clone)]
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pub struct Wtf8Buf {
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bytes: Vec<u8>,
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/// Do we know that `bytes` holds a valid UTF-8 encoding? We can easily
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/// know this if we're constructed from a `String` or `&str`.
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///
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/// It is possible for `bytes` to have valid UTF-8 without this being
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/// set, such as when we're concatenating `&Wtf8`'s and surrogates become
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/// paired, as we don't bother to rescan the entire string.
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is_known_utf8: bool,
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}
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impl ops::Deref for Wtf8Buf {
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type Target = Wtf8;
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fn deref(&self) -> &Wtf8 {
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self.as_slice()
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}
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}
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impl ops::DerefMut for Wtf8Buf {
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fn deref_mut(&mut self) -> &mut Wtf8 {
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self.as_mut_slice()
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}
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}
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/// Formats the string in double quotes, with characters escaped according to
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/// [`char::escape_debug`] and unpaired surrogates represented as `\u{xxxx}`,
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/// where each `x` is a hexadecimal digit.
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///
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/// For example, the code units [U+0061, U+D800, U+000A] are formatted as
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/// `"a\u{D800}\n"`.
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impl fmt::Debug for Wtf8Buf {
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#[inline]
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fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
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fmt::Debug::fmt(&**self, formatter)
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}
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}
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/// Formats the string with unpaired surrogates substituted with the replacement
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/// character, U+FFFD.
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impl fmt::Display for Wtf8Buf {
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fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
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if let Some(s) = self.as_known_utf8() {
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fmt::Display::fmt(s, formatter)
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} else {
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fmt::Display::fmt(&**self, formatter)
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}
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}
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}
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impl Wtf8Buf {
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/// Creates a new, empty WTF-8 string.
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#[inline]
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pub fn new() -> Wtf8Buf {
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Wtf8Buf { bytes: Vec::new(), is_known_utf8: true }
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}
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/// Creates a new, empty WTF-8 string with pre-allocated capacity for `capacity` bytes.
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#[inline]
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pub fn with_capacity(capacity: usize) -> Wtf8Buf {
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Wtf8Buf { bytes: Vec::with_capacity(capacity), is_known_utf8: true }
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}
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/// Creates a WTF-8 string from a WTF-8 byte vec.
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///
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/// Since the byte vec is not checked for valid WTF-8, this function is
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/// marked unsafe.
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#[inline]
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pub unsafe fn from_bytes_unchecked(value: Vec<u8>) -> Wtf8Buf {
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Wtf8Buf { bytes: value, is_known_utf8: false }
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}
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/// Creates a WTF-8 string from a UTF-8 `String`.
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///
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/// This takes ownership of the `String` and does not copy.
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///
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/// Since WTF-8 is a superset of UTF-8, this always succeeds.
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#[inline]
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pub const fn from_string(string: String) -> Wtf8Buf {
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Wtf8Buf { bytes: string.into_bytes(), is_known_utf8: true }
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}
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/// Creates a WTF-8 string from a UTF-8 `&str` slice.
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///
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/// This copies the content of the slice.
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///
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/// Since WTF-8 is a superset of UTF-8, this always succeeds.
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#[inline]
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pub fn from_str(s: &str) -> Wtf8Buf {
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Wtf8Buf { bytes: s.as_bytes().to_vec(), is_known_utf8: true }
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}
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pub fn clear(&mut self) {
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self.bytes.clear();
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self.is_known_utf8 = true;
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}
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/// Creates a WTF-8 string from a potentially ill-formed UTF-16 slice of 16-bit code units.
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///
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/// This is lossless: calling `.encode_wide()` on the resulting string
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/// will always return the original code units.
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pub fn from_wide(v: &[u16]) -> Wtf8Buf {
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let mut string = Wtf8Buf::with_capacity(v.len());
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for item in char::decode_utf16(v.iter().cloned()) {
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match item {
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Ok(ch) => string.push_char(ch),
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Err(surrogate) => {
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let surrogate = surrogate.unpaired_surrogate();
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// Surrogates are known to be in the code point range.
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let code_point = unsafe { CodePoint::from_u32_unchecked(surrogate as u32) };
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// The string will now contain an unpaired surrogate.
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string.is_known_utf8 = false;
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// Skip the WTF-8 concatenation check,
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// surrogate pairs are already decoded by decode_utf16
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string.push_code_point_unchecked(code_point);
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}
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}
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}
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string
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}
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/// Appends the given `char` to the end of this string.
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/// This does **not** include the WTF-8 concatenation check or `is_known_utf8` check.
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/// Copied from String::push.
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fn push_code_point_unchecked(&mut self, code_point: CodePoint) {
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let mut bytes = [0; MAX_LEN_UTF8];
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let bytes = encode_utf8_raw(code_point.value, &mut bytes);
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self.bytes.extend_from_slice(bytes)
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}
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#[inline]
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pub fn as_slice(&self) -> &Wtf8 {
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unsafe { Wtf8::from_bytes_unchecked(&self.bytes) }
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}
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#[inline]
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pub fn as_mut_slice(&mut self) -> &mut Wtf8 {
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// Safety: `Wtf8` doesn't expose any way to mutate the bytes that would
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// cause them to change from well-formed UTF-8 to ill-formed UTF-8,
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// which would break the assumptions of the `is_known_utf8` field.
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unsafe { Wtf8::from_mut_bytes_unchecked(&mut self.bytes) }
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}
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/// Converts the string to UTF-8 without validation, if it was created from
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/// valid UTF-8.
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#[inline]
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fn as_known_utf8(&self) -> Option<&str> {
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if self.is_known_utf8 {
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// SAFETY: The buffer is known to be valid UTF-8.
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Some(unsafe { str::from_utf8_unchecked(self.as_bytes()) })
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} else {
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None
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}
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}
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/// Reserves capacity for at least `additional` more bytes to be inserted
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/// in the given `Wtf8Buf`.
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/// The collection may reserve more space to avoid frequent reallocations.
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///
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/// # Panics
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///
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/// Panics if the new capacity exceeds `isize::MAX` bytes.
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#[inline]
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pub fn reserve(&mut self, additional: usize) {
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self.bytes.reserve(additional)
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}
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/// Tries to reserve capacity for at least `additional` more bytes to be
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/// inserted in the given `Wtf8Buf`. The `Wtf8Buf` may reserve more space to
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/// avoid frequent reallocations. After calling `try_reserve`, capacity will
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/// be greater than or equal to `self.len() + additional`. Does nothing if
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/// capacity is already sufficient. This method preserves the contents even
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/// if an error occurs.
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///
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/// # Errors
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///
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/// If the capacity overflows, or the allocator reports a failure, then an error
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/// is returned.
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#[inline]
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pub fn try_reserve(&mut self, additional: usize) -> Result<(), TryReserveError> {
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self.bytes.try_reserve(additional)
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}
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#[inline]
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pub fn reserve_exact(&mut self, additional: usize) {
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self.bytes.reserve_exact(additional)
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}
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/// Tries to reserve the minimum capacity for exactly `additional` more
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/// bytes to be inserted in the given `Wtf8Buf`. After calling
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/// `try_reserve_exact`, capacity will be greater than or equal to
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/// `self.len() + additional` if it returns `Ok(())`.
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/// Does nothing if the capacity is already sufficient.
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///
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/// Note that the allocator may give the `Wtf8Buf` more space than it
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/// requests. Therefore, capacity can not be relied upon to be precisely
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/// minimal. Prefer [`try_reserve`] if future insertions are expected.
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///
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/// [`try_reserve`]: Wtf8Buf::try_reserve
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///
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/// # Errors
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///
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/// If the capacity overflows, or the allocator reports a failure, then an error
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/// is returned.
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#[inline]
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pub fn try_reserve_exact(&mut self, additional: usize) -> Result<(), TryReserveError> {
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self.bytes.try_reserve_exact(additional)
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}
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#[inline]
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pub fn shrink_to_fit(&mut self) {
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self.bytes.shrink_to_fit()
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}
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#[inline]
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pub fn shrink_to(&mut self, min_capacity: usize) {
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self.bytes.shrink_to(min_capacity)
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}
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#[inline]
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pub fn leak<'a>(self) -> &'a mut Wtf8 {
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unsafe { Wtf8::from_mut_bytes_unchecked(self.bytes.leak()) }
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}
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/// Returns the number of bytes that this string buffer can hold without reallocating.
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#[inline]
|
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pub fn capacity(&self) -> usize {
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self.bytes.capacity()
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}
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|
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/// Append a UTF-8 slice at the end of the string.
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#[inline]
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pub fn push_str(&mut self, other: &str) {
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self.bytes.extend_from_slice(other.as_bytes())
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}
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/// Append a WTF-8 slice at the end of the string.
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///
|
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/// This replaces newly paired surrogates at the boundary
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/// with a supplementary code point,
|
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/// like concatenating ill-formed UTF-16 strings effectively would.
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#[inline]
|
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pub fn push_wtf8(&mut self, other: &Wtf8) {
|
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match ((&*self).final_lead_surrogate(), other.initial_trail_surrogate()) {
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// Replace newly paired surrogates by a supplementary code point.
|
||||
(Some(lead), Some(trail)) => {
|
||||
let len_without_lead_surrogate = self.len() - 3;
|
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self.bytes.truncate(len_without_lead_surrogate);
|
||||
let other_without_trail_surrogate = &other.bytes[3..];
|
||||
// 4 bytes for the supplementary code point
|
||||
self.bytes.reserve(4 + other_without_trail_surrogate.len());
|
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self.push_char(decode_surrogate_pair(lead, trail));
|
||||
self.bytes.extend_from_slice(other_without_trail_surrogate);
|
||||
}
|
||||
_ => {
|
||||
// If we'll be pushing a string containing a surrogate, we may
|
||||
// no longer have UTF-8.
|
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if self.is_known_utf8 && other.next_surrogate(0).is_some() {
|
||||
self.is_known_utf8 = false;
|
||||
}
|
||||
|
||||
self.bytes.extend_from_slice(&other.bytes);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/// Append a Unicode scalar value at the end of the string.
|
||||
#[inline]
|
||||
pub fn push_char(&mut self, c: char) {
|
||||
self.push_code_point_unchecked(CodePoint::from_char(c))
|
||||
}
|
||||
|
||||
/// Append a code point at the end of the string.
|
||||
///
|
||||
/// This replaces newly paired surrogates at the boundary
|
||||
/// with a supplementary code point,
|
||||
/// like concatenating ill-formed UTF-16 strings effectively would.
|
||||
#[inline]
|
||||
pub fn push(&mut self, code_point: CodePoint) {
|
||||
if let Some(trail) = code_point.to_trail_surrogate() {
|
||||
if let Some(lead) = (&*self).final_lead_surrogate() {
|
||||
let len_without_lead_surrogate = self.len() - 3;
|
||||
self.bytes.truncate(len_without_lead_surrogate);
|
||||
self.push_char(decode_surrogate_pair(lead, trail));
|
||||
return;
|
||||
}
|
||||
|
||||
// We're pushing a trailing surrogate.
|
||||
self.is_known_utf8 = false;
|
||||
} else if code_point.to_lead_surrogate().is_some() {
|
||||
// We're pushing a leading surrogate.
|
||||
self.is_known_utf8 = false;
|
||||
}
|
||||
|
||||
// No newly paired surrogates at the boundary.
|
||||
self.push_code_point_unchecked(code_point)
|
||||
}
|
||||
|
||||
/// Shortens a string to the specified length.
|
||||
///
|
||||
/// # Panics
|
||||
///
|
||||
/// Panics if `new_len` > current length,
|
||||
/// or if `new_len` is not a code point boundary.
|
||||
#[inline]
|
||||
pub fn truncate(&mut self, new_len: usize) {
|
||||
assert!(is_code_point_boundary(self, new_len));
|
||||
self.bytes.truncate(new_len)
|
||||
}
|
||||
|
||||
/// Consumes the WTF-8 string and tries to convert it to a vec of bytes.
|
||||
#[inline]
|
||||
pub fn into_bytes(self) -> Vec<u8> {
|
||||
self.bytes
|
||||
}
|
||||
|
||||
/// Consumes the WTF-8 string and tries to convert it to UTF-8.
|
||||
///
|
||||
/// This does not copy the data.
|
||||
///
|
||||
/// If the contents are not well-formed UTF-8
|
||||
/// (that is, if the string contains surrogates),
|
||||
/// the original WTF-8 string is returned instead.
|
||||
pub fn into_string(self) -> Result<String, Wtf8Buf> {
|
||||
if self.is_known_utf8 || self.next_surrogate(0).is_none() {
|
||||
Ok(unsafe { String::from_utf8_unchecked(self.bytes) })
|
||||
} else {
|
||||
Err(self)
|
||||
}
|
||||
}
|
||||
|
||||
/// Consumes the WTF-8 string and converts it lossily to UTF-8.
|
||||
///
|
||||
/// This does not copy the data (but may overwrite parts of it in place).
|
||||
///
|
||||
/// Surrogates are replaced with `"\u{FFFD}"` (the replacement character “�”)
|
||||
pub fn into_string_lossy(mut self) -> String {
|
||||
if !self.is_known_utf8 {
|
||||
let mut pos = 0;
|
||||
while let Some((surrogate_pos, _)) = self.next_surrogate(pos) {
|
||||
pos = surrogate_pos + 3;
|
||||
// Surrogates and the replacement character are all 3 bytes, so
|
||||
// they can substituted in-place.
|
||||
self.bytes[surrogate_pos..pos]
|
||||
.copy_from_slice(UTF8_REPLACEMENT_CHARACTER.as_bytes());
|
||||
}
|
||||
}
|
||||
unsafe { String::from_utf8_unchecked(self.bytes) }
|
||||
}
|
||||
|
||||
/// Converts this `Wtf8Buf` into a boxed `Wtf8`.
|
||||
#[inline]
|
||||
pub fn into_box(self) -> Box<Wtf8> {
|
||||
// SAFETY: relies on `Wtf8` being `repr(transparent)`.
|
||||
unsafe { mem::transmute(self.bytes.into_boxed_slice()) }
|
||||
}
|
||||
|
||||
/// Converts a `Box<Wtf8>` into a `Wtf8Buf`.
|
||||
pub fn from_box(boxed: Box<Wtf8>) -> Wtf8Buf {
|
||||
let bytes: Box<[u8]> = unsafe { mem::transmute(boxed) };
|
||||
Wtf8Buf { bytes: bytes.into_vec(), is_known_utf8: false }
|
||||
}
|
||||
|
||||
/// Provides plumbing to core `Vec::extend_from_slice`.
|
||||
/// More well behaving alternative to allowing outer types
|
||||
/// full mutable access to the core `Vec`.
|
||||
#[inline]
|
||||
pub(crate) fn extend_from_slice(&mut self, other: &[u8]) {
|
||||
self.bytes.extend_from_slice(other);
|
||||
self.is_known_utf8 = false;
|
||||
}
|
||||
}
|
||||
|
||||
/// Creates a new WTF-8 string from an iterator of code points.
|
||||
///
|
||||
/// This replaces surrogate code point pairs with supplementary code points,
|
||||
/// like concatenating ill-formed UTF-16 strings effectively would.
|
||||
impl FromIterator<CodePoint> for Wtf8Buf {
|
||||
fn from_iter<T: IntoIterator<Item = CodePoint>>(iter: T) -> Wtf8Buf {
|
||||
let mut string = Wtf8Buf::new();
|
||||
string.extend(iter);
|
||||
string
|
||||
}
|
||||
}
|
||||
|
||||
/// Append code points from an iterator to the string.
|
||||
///
|
||||
/// This replaces surrogate code point pairs with supplementary code points,
|
||||
/// like concatenating ill-formed UTF-16 strings effectively would.
|
||||
impl Extend<CodePoint> for Wtf8Buf {
|
||||
fn extend<T: IntoIterator<Item = CodePoint>>(&mut self, iter: T) {
|
||||
let iterator = iter.into_iter();
|
||||
let (low, _high) = iterator.size_hint();
|
||||
// Lower bound of one byte per code point (ASCII only)
|
||||
self.bytes.reserve(low);
|
||||
iterator.for_each(move |code_point| self.push(code_point));
|
||||
}
|
||||
|
||||
#[inline]
|
||||
fn extend_one(&mut self, code_point: CodePoint) {
|
||||
self.push(code_point);
|
||||
}
|
||||
|
||||
#[inline]
|
||||
fn extend_reserve(&mut self, additional: usize) {
|
||||
// Lower bound of one byte per code point (ASCII only)
|
||||
self.bytes.reserve(additional);
|
||||
}
|
||||
}
|
||||
|
||||
/// A borrowed slice of well-formed WTF-8 data.
|
||||
///
|
||||
/// Similar to `&str`, but can additionally contain surrogate code points
|
||||
/// if they’re not in a surrogate pair.
|
||||
#[derive(Eq, Ord, PartialEq, PartialOrd)]
|
||||
#[repr(transparent)]
|
||||
pub struct Wtf8 {
|
||||
bytes: [u8],
|
||||
}
|
||||
|
||||
impl AsInner<[u8]> for Wtf8 {
|
||||
#[inline]
|
||||
fn as_inner(&self) -> &[u8] {
|
||||
&self.bytes
|
||||
}
|
||||
}
|
||||
|
||||
/// Formats the string in double quotes, with characters escaped according to
|
||||
/// [`char::escape_debug`] and unpaired surrogates represented as `\u{xxxx}`,
|
||||
/// where each `x` is a hexadecimal digit.
|
||||
impl fmt::Debug for Wtf8 {
|
||||
fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
|
||||
fn write_str_escaped(f: &mut fmt::Formatter<'_>, s: &str) -> fmt::Result {
|
||||
use crate::fmt::Write;
|
||||
for c in s.chars().flat_map(|c| c.escape_debug()) {
|
||||
f.write_char(c)?
|
||||
}
|
||||
Ok(())
|
||||
}
|
||||
|
||||
formatter.write_str("\"")?;
|
||||
let mut pos = 0;
|
||||
while let Some((surrogate_pos, surrogate)) = self.next_surrogate(pos) {
|
||||
write_str_escaped(formatter, unsafe {
|
||||
str::from_utf8_unchecked(&self.bytes[pos..surrogate_pos])
|
||||
})?;
|
||||
write!(formatter, "\\u{{{:x}}}", surrogate)?;
|
||||
pos = surrogate_pos + 3;
|
||||
}
|
||||
write_str_escaped(formatter, unsafe { str::from_utf8_unchecked(&self.bytes[pos..]) })?;
|
||||
formatter.write_str("\"")
|
||||
}
|
||||
}
|
||||
|
||||
/// Formats the string with unpaired surrogates substituted with the replacement
|
||||
/// character, U+FFFD.
|
||||
impl fmt::Display for Wtf8 {
|
||||
fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
|
||||
let wtf8_bytes = &self.bytes;
|
||||
let mut pos = 0;
|
||||
loop {
|
||||
match self.next_surrogate(pos) {
|
||||
Some((surrogate_pos, _)) => {
|
||||
formatter.write_str(unsafe {
|
||||
str::from_utf8_unchecked(&wtf8_bytes[pos..surrogate_pos])
|
||||
})?;
|
||||
formatter.write_str(UTF8_REPLACEMENT_CHARACTER)?;
|
||||
pos = surrogate_pos + 3;
|
||||
}
|
||||
None => {
|
||||
let s = unsafe { str::from_utf8_unchecked(&wtf8_bytes[pos..]) };
|
||||
if pos == 0 { return s.fmt(formatter) } else { return formatter.write_str(s) }
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
impl Wtf8 {
|
||||
/// Creates a WTF-8 slice from a UTF-8 `&str` slice.
|
||||
///
|
||||
/// Since WTF-8 is a superset of UTF-8, this always succeeds.
|
||||
#[inline]
|
||||
pub fn from_str(value: &str) -> &Wtf8 {
|
||||
unsafe { Wtf8::from_bytes_unchecked(value.as_bytes()) }
|
||||
}
|
||||
|
||||
/// Creates a WTF-8 slice from a WTF-8 byte slice.
|
||||
///
|
||||
/// Since the byte slice is not checked for valid WTF-8, this functions is
|
||||
/// marked unsafe.
|
||||
#[inline]
|
||||
pub unsafe fn from_bytes_unchecked(value: &[u8]) -> &Wtf8 {
|
||||
// SAFETY: start with &[u8], end with fancy &[u8]
|
||||
unsafe { &*(value as *const [u8] as *const Wtf8) }
|
||||
}
|
||||
|
||||
/// Creates a mutable WTF-8 slice from a mutable WTF-8 byte slice.
|
||||
///
|
||||
/// Since the byte slice is not checked for valid WTF-8, this functions is
|
||||
/// marked unsafe.
|
||||
#[inline]
|
||||
unsafe fn from_mut_bytes_unchecked(value: &mut [u8]) -> &mut Wtf8 {
|
||||
// SAFETY: start with &mut [u8], end with fancy &mut [u8]
|
||||
unsafe { &mut *(value as *mut [u8] as *mut Wtf8) }
|
||||
}
|
||||
|
||||
/// Returns the length, in WTF-8 bytes.
|
||||
#[inline]
|
||||
pub fn len(&self) -> usize {
|
||||
self.bytes.len()
|
||||
}
|
||||
|
||||
#[inline]
|
||||
pub fn is_empty(&self) -> bool {
|
||||
self.bytes.is_empty()
|
||||
}
|
||||
|
||||
/// Returns the code point at `position` if it is in the ASCII range,
|
||||
/// or `b'\xFF'` otherwise.
|
||||
///
|
||||
/// # Panics
|
||||
///
|
||||
/// Panics if `position` is beyond the end of the string.
|
||||
#[inline]
|
||||
pub fn ascii_byte_at(&self, position: usize) -> u8 {
|
||||
match self.bytes[position] {
|
||||
ascii_byte @ 0x00..=0x7F => ascii_byte,
|
||||
_ => 0xFF,
|
||||
}
|
||||
}
|
||||
|
||||
/// Returns an iterator for the string’s code points.
|
||||
#[inline]
|
||||
pub fn code_points(&self) -> Wtf8CodePoints<'_> {
|
||||
Wtf8CodePoints { bytes: self.bytes.iter() }
|
||||
}
|
||||
|
||||
/// Access raw bytes of WTF-8 data
|
||||
#[inline]
|
||||
pub fn as_bytes(&self) -> &[u8] {
|
||||
&self.bytes
|
||||
}
|
||||
|
||||
/// Tries to convert the string to UTF-8 and return a `&str` slice.
|
||||
///
|
||||
/// Returns `None` if the string contains surrogates.
|
||||
///
|
||||
/// This does not copy the data.
|
||||
#[inline]
|
||||
pub fn as_str(&self) -> Result<&str, str::Utf8Error> {
|
||||
str::from_utf8(&self.bytes)
|
||||
}
|
||||
|
||||
/// Creates an owned `Wtf8Buf` from a borrowed `Wtf8`.
|
||||
pub fn to_owned(&self) -> Wtf8Buf {
|
||||
Wtf8Buf { bytes: self.bytes.to_vec(), is_known_utf8: false }
|
||||
}
|
||||
|
||||
/// Lossily converts the string to UTF-8.
|
||||
/// Returns a UTF-8 `&str` slice if the contents are well-formed in UTF-8.
|
||||
///
|
||||
/// Surrogates are replaced with `"\u{FFFD}"` (the replacement character “�”).
|
||||
///
|
||||
/// This only copies the data if necessary (if it contains any surrogate).
|
||||
pub fn to_string_lossy(&self) -> Cow<'_, str> {
|
||||
let Some((surrogate_pos, _)) = self.next_surrogate(0) else {
|
||||
return Cow::Borrowed(unsafe { str::from_utf8_unchecked(&self.bytes) });
|
||||
};
|
||||
let wtf8_bytes = &self.bytes;
|
||||
let mut utf8_bytes = Vec::with_capacity(self.len());
|
||||
utf8_bytes.extend_from_slice(&wtf8_bytes[..surrogate_pos]);
|
||||
utf8_bytes.extend_from_slice(UTF8_REPLACEMENT_CHARACTER.as_bytes());
|
||||
let mut pos = surrogate_pos + 3;
|
||||
loop {
|
||||
match self.next_surrogate(pos) {
|
||||
Some((surrogate_pos, _)) => {
|
||||
utf8_bytes.extend_from_slice(&wtf8_bytes[pos..surrogate_pos]);
|
||||
utf8_bytes.extend_from_slice(UTF8_REPLACEMENT_CHARACTER.as_bytes());
|
||||
pos = surrogate_pos + 3;
|
||||
}
|
||||
None => {
|
||||
utf8_bytes.extend_from_slice(&wtf8_bytes[pos..]);
|
||||
return Cow::Owned(unsafe { String::from_utf8_unchecked(utf8_bytes) });
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/// Converts the WTF-8 string to potentially ill-formed UTF-16
|
||||
/// and return an iterator of 16-bit code units.
|
||||
///
|
||||
/// This is lossless:
|
||||
/// calling `Wtf8Buf::from_ill_formed_utf16` on the resulting code units
|
||||
/// would always return the original WTF-8 string.
|
||||
#[inline]
|
||||
pub fn encode_wide(&self) -> EncodeWide<'_> {
|
||||
EncodeWide { code_points: self.code_points(), extra: 0 }
|
||||
}
|
||||
|
||||
#[inline]
|
||||
fn next_surrogate(&self, mut pos: usize) -> Option<(usize, u16)> {
|
||||
let mut iter = self.bytes[pos..].iter();
|
||||
loop {
|
||||
let b = *iter.next()?;
|
||||
if b < 0x80 {
|
||||
pos += 1;
|
||||
} else if b < 0xE0 {
|
||||
iter.next();
|
||||
pos += 2;
|
||||
} else if b == 0xED {
|
||||
match (iter.next(), iter.next()) {
|
||||
(Some(&b2), Some(&b3)) if b2 >= 0xA0 => {
|
||||
return Some((pos, decode_surrogate(b2, b3)));
|
||||
}
|
||||
_ => pos += 3,
|
||||
}
|
||||
} else if b < 0xF0 {
|
||||
iter.next();
|
||||
iter.next();
|
||||
pos += 3;
|
||||
} else {
|
||||
iter.next();
|
||||
iter.next();
|
||||
iter.next();
|
||||
pos += 4;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
#[inline]
|
||||
fn final_lead_surrogate(&self) -> Option<u16> {
|
||||
match self.bytes {
|
||||
[.., 0xED, b2 @ 0xA0..=0xAF, b3] => Some(decode_surrogate(b2, b3)),
|
||||
_ => None,
|
||||
}
|
||||
}
|
||||
|
||||
#[inline]
|
||||
fn initial_trail_surrogate(&self) -> Option<u16> {
|
||||
match self.bytes {
|
||||
[0xED, b2 @ 0xB0..=0xBF, b3, ..] => Some(decode_surrogate(b2, b3)),
|
||||
_ => None,
|
||||
}
|
||||
}
|
||||
|
||||
pub fn clone_into(&self, buf: &mut Wtf8Buf) {
|
||||
buf.is_known_utf8 = false;
|
||||
self.bytes.clone_into(&mut buf.bytes);
|
||||
}
|
||||
|
||||
/// Boxes this `Wtf8`.
|
||||
#[inline]
|
||||
pub fn into_box(&self) -> Box<Wtf8> {
|
||||
let boxed: Box<[u8]> = self.bytes.into();
|
||||
unsafe { mem::transmute(boxed) }
|
||||
}
|
||||
|
||||
/// Creates a boxed, empty `Wtf8`.
|
||||
pub fn empty_box() -> Box<Wtf8> {
|
||||
let boxed: Box<[u8]> = Default::default();
|
||||
unsafe { mem::transmute(boxed) }
|
||||
}
|
||||
|
||||
#[inline]
|
||||
pub fn into_arc(&self) -> Arc<Wtf8> {
|
||||
let arc: Arc<[u8]> = Arc::from(&self.bytes);
|
||||
unsafe { Arc::from_raw(Arc::into_raw(arc) as *const Wtf8) }
|
||||
}
|
||||
|
||||
#[inline]
|
||||
pub fn into_rc(&self) -> Rc<Wtf8> {
|
||||
let rc: Rc<[u8]> = Rc::from(&self.bytes);
|
||||
unsafe { Rc::from_raw(Rc::into_raw(rc) as *const Wtf8) }
|
||||
}
|
||||
|
||||
#[inline]
|
||||
pub fn make_ascii_lowercase(&mut self) {
|
||||
self.bytes.make_ascii_lowercase()
|
||||
}
|
||||
|
||||
#[inline]
|
||||
pub fn make_ascii_uppercase(&mut self) {
|
||||
self.bytes.make_ascii_uppercase()
|
||||
}
|
||||
|
||||
#[inline]
|
||||
pub fn to_ascii_lowercase(&self) -> Wtf8Buf {
|
||||
Wtf8Buf { bytes: self.bytes.to_ascii_lowercase(), is_known_utf8: false }
|
||||
}
|
||||
|
||||
#[inline]
|
||||
pub fn to_ascii_uppercase(&self) -> Wtf8Buf {
|
||||
Wtf8Buf { bytes: self.bytes.to_ascii_uppercase(), is_known_utf8: false }
|
||||
}
|
||||
|
||||
#[inline]
|
||||
pub fn is_ascii(&self) -> bool {
|
||||
self.bytes.is_ascii()
|
||||
}
|
||||
|
||||
#[inline]
|
||||
pub fn eq_ignore_ascii_case(&self, other: &Self) -> bool {
|
||||
self.bytes.eq_ignore_ascii_case(&other.bytes)
|
||||
}
|
||||
}
|
||||
|
||||
/// Returns a slice of the given string for the byte range \[`begin`..`end`).
|
||||
///
|
||||
/// # Panics
|
||||
///
|
||||
/// Panics when `begin` and `end` do not point to code point boundaries,
|
||||
/// or point beyond the end of the string.
|
||||
impl ops::Index<ops::Range<usize>> for Wtf8 {
|
||||
type Output = Wtf8;
|
||||
|
||||
#[inline]
|
||||
fn index(&self, range: ops::Range<usize>) -> &Wtf8 {
|
||||
// is_code_point_boundary checks that the index is in [0, .len()]
|
||||
if range.start <= range.end
|
||||
&& is_code_point_boundary(self, range.start)
|
||||
&& is_code_point_boundary(self, range.end)
|
||||
{
|
||||
unsafe { slice_unchecked(self, range.start, range.end) }
|
||||
} else {
|
||||
slice_error_fail(self, range.start, range.end)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/// Returns a slice of the given string from byte `begin` to its end.
|
||||
///
|
||||
/// # Panics
|
||||
///
|
||||
/// Panics when `begin` is not at a code point boundary,
|
||||
/// or is beyond the end of the string.
|
||||
impl ops::Index<ops::RangeFrom<usize>> for Wtf8 {
|
||||
type Output = Wtf8;
|
||||
|
||||
#[inline]
|
||||
fn index(&self, range: ops::RangeFrom<usize>) -> &Wtf8 {
|
||||
// is_code_point_boundary checks that the index is in [0, .len()]
|
||||
if is_code_point_boundary(self, range.start) {
|
||||
unsafe { slice_unchecked(self, range.start, self.len()) }
|
||||
} else {
|
||||
slice_error_fail(self, range.start, self.len())
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/// Returns a slice of the given string from its beginning to byte `end`.
|
||||
///
|
||||
/// # Panics
|
||||
///
|
||||
/// Panics when `end` is not at a code point boundary,
|
||||
/// or is beyond the end of the string.
|
||||
impl ops::Index<ops::RangeTo<usize>> for Wtf8 {
|
||||
type Output = Wtf8;
|
||||
|
||||
#[inline]
|
||||
fn index(&self, range: ops::RangeTo<usize>) -> &Wtf8 {
|
||||
// is_code_point_boundary checks that the index is in [0, .len()]
|
||||
if is_code_point_boundary(self, range.end) {
|
||||
unsafe { slice_unchecked(self, 0, range.end) }
|
||||
} else {
|
||||
slice_error_fail(self, 0, range.end)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
impl ops::Index<ops::RangeFull> for Wtf8 {
|
||||
type Output = Wtf8;
|
||||
|
||||
#[inline]
|
||||
fn index(&self, _range: ops::RangeFull) -> &Wtf8 {
|
||||
self
|
||||
}
|
||||
}
|
||||
|
||||
#[inline]
|
||||
fn decode_surrogate(second_byte: u8, third_byte: u8) -> u16 {
|
||||
// The first byte is assumed to be 0xED
|
||||
0xD800 | (second_byte as u16 & 0x3F) << 6 | third_byte as u16 & 0x3F
|
||||
}
|
||||
|
||||
#[inline]
|
||||
fn decode_surrogate_pair(lead: u16, trail: u16) -> char {
|
||||
let code_point = 0x10000 + ((((lead - 0xD800) as u32) << 10) | (trail - 0xDC00) as u32);
|
||||
unsafe { char::from_u32_unchecked(code_point) }
|
||||
}
|
||||
|
||||
/// Copied from str::is_char_boundary
|
||||
#[inline]
|
||||
pub fn is_code_point_boundary(slice: &Wtf8, index: usize) -> bool {
|
||||
if index == 0 {
|
||||
return true;
|
||||
}
|
||||
match slice.bytes.get(index) {
|
||||
None => index == slice.len(),
|
||||
Some(&b) => (b as i8) >= -0x40,
|
||||
}
|
||||
}
|
||||
|
||||
/// Verify that `index` is at the edge of either a valid UTF-8 codepoint
|
||||
/// (i.e. a codepoint that's not a surrogate) or of the whole string.
|
||||
///
|
||||
/// These are the cases currently permitted by `OsStr::slice_encoded_bytes`.
|
||||
/// Splitting between surrogates is valid as far as WTF-8 is concerned, but
|
||||
/// we do not permit it in the public API because WTF-8 is considered an
|
||||
/// implementation detail.
|
||||
#[track_caller]
|
||||
#[inline]
|
||||
pub fn check_utf8_boundary(slice: &Wtf8, index: usize) {
|
||||
if index == 0 {
|
||||
return;
|
||||
}
|
||||
match slice.bytes.get(index) {
|
||||
Some(0xED) => (), // Might be a surrogate
|
||||
Some(&b) if (b as i8) >= -0x40 => return,
|
||||
Some(_) => panic!("byte index {index} is not a codepoint boundary"),
|
||||
None if index == slice.len() => return,
|
||||
None => panic!("byte index {index} is out of bounds"),
|
||||
}
|
||||
if slice.bytes[index + 1] >= 0xA0 {
|
||||
// There's a surrogate after index. Now check before index.
|
||||
if index >= 3 && slice.bytes[index - 3] == 0xED && slice.bytes[index - 2] >= 0xA0 {
|
||||
panic!("byte index {index} lies between surrogate codepoints");
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/// Copied from core::str::raw::slice_unchecked
|
||||
#[inline]
|
||||
pub unsafe fn slice_unchecked(s: &Wtf8, begin: usize, end: usize) -> &Wtf8 {
|
||||
// SAFETY: memory layout of a &[u8] and &Wtf8 are the same
|
||||
unsafe {
|
||||
let len = end - begin;
|
||||
let start = s.as_bytes().as_ptr().add(begin);
|
||||
Wtf8::from_bytes_unchecked(slice::from_raw_parts(start, len))
|
||||
}
|
||||
}
|
||||
|
||||
/// Copied from core::str::raw::slice_error_fail
|
||||
#[inline(never)]
|
||||
pub fn slice_error_fail(s: &Wtf8, begin: usize, end: usize) -> ! {
|
||||
assert!(begin <= end);
|
||||
panic!("index {begin} and/or {end} in `{s:?}` do not lie on character boundary");
|
||||
}
|
||||
|
||||
/// Iterator for the code points of a WTF-8 string.
|
||||
///
|
||||
/// Created with the method `.code_points()`.
|
||||
#[derive(Clone)]
|
||||
pub struct Wtf8CodePoints<'a> {
|
||||
bytes: slice::Iter<'a, u8>,
|
||||
}
|
||||
|
||||
impl Iterator for Wtf8CodePoints<'_> {
|
||||
type Item = CodePoint;
|
||||
|
||||
#[inline]
|
||||
fn next(&mut self) -> Option<CodePoint> {
|
||||
// SAFETY: `self.bytes` has been created from a WTF-8 string
|
||||
unsafe { next_code_point(&mut self.bytes).map(|c| CodePoint { value: c }) }
|
||||
}
|
||||
|
||||
#[inline]
|
||||
fn size_hint(&self) -> (usize, Option<usize>) {
|
||||
let len = self.bytes.len();
|
||||
(len.saturating_add(3) / 4, Some(len))
|
||||
}
|
||||
}
|
||||
|
||||
/// Generates a wide character sequence for potentially ill-formed UTF-16.
|
||||
#[stable(feature = "rust1", since = "1.0.0")]
|
||||
#[derive(Clone)]
|
||||
pub struct EncodeWide<'a> {
|
||||
code_points: Wtf8CodePoints<'a>,
|
||||
extra: u16,
|
||||
}
|
||||
|
||||
// Copied from libunicode/u_str.rs
|
||||
#[stable(feature = "rust1", since = "1.0.0")]
|
||||
impl Iterator for EncodeWide<'_> {
|
||||
type Item = u16;
|
||||
|
||||
#[inline]
|
||||
fn next(&mut self) -> Option<u16> {
|
||||
if self.extra != 0 {
|
||||
let tmp = self.extra;
|
||||
self.extra = 0;
|
||||
return Some(tmp);
|
||||
}
|
||||
|
||||
let mut buf = [0; MAX_LEN_UTF16];
|
||||
self.code_points.next().map(|code_point| {
|
||||
let n = encode_utf16_raw(code_point.value, &mut buf).len();
|
||||
if n == 2 {
|
||||
self.extra = buf[1];
|
||||
}
|
||||
buf[0]
|
||||
})
|
||||
}
|
||||
|
||||
#[inline]
|
||||
fn size_hint(&self) -> (usize, Option<usize>) {
|
||||
let (low, high) = self.code_points.size_hint();
|
||||
let ext = (self.extra != 0) as usize;
|
||||
// every code point gets either one u16 or two u16,
|
||||
// so this iterator is between 1 or 2 times as
|
||||
// long as the underlying iterator.
|
||||
(low + ext, high.and_then(|n| n.checked_mul(2)).and_then(|n| n.checked_add(ext)))
|
||||
}
|
||||
}
|
||||
|
||||
#[stable(feature = "encode_wide_fused_iterator", since = "1.62.0")]
|
||||
impl FusedIterator for EncodeWide<'_> {}
|
||||
|
||||
impl Hash for CodePoint {
|
||||
#[inline]
|
||||
fn hash<H: Hasher>(&self, state: &mut H) {
|
||||
self.value.hash(state)
|
||||
}
|
||||
}
|
||||
|
||||
impl Hash for Wtf8Buf {
|
||||
#[inline]
|
||||
fn hash<H: Hasher>(&self, state: &mut H) {
|
||||
state.write(&self.bytes);
|
||||
0xfeu8.hash(state)
|
||||
}
|
||||
}
|
||||
|
||||
impl Hash for Wtf8 {
|
||||
#[inline]
|
||||
fn hash<H: Hasher>(&self, state: &mut H) {
|
||||
state.write(&self.bytes);
|
||||
0xfeu8.hash(state)
|
||||
}
|
||||
}
|
||||
|
||||
#[unstable(feature = "clone_to_uninit", issue = "126799")]
|
||||
unsafe impl CloneToUninit for Wtf8 {
|
||||
#[inline]
|
||||
#[cfg_attr(debug_assertions, track_caller)]
|
||||
unsafe fn clone_to_uninit(&self, dst: *mut u8) {
|
||||
// SAFETY: we're just a transparent wrapper around [u8]
|
||||
unsafe { self.bytes.clone_to_uninit(dst) }
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user