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Diffstat (limited to 'library/std/src/sys_common/wtf8.rs')
| -rw-r--r-- | library/std/src/sys_common/wtf8.rs | 1083 |
1 files changed, 0 insertions, 1083 deletions
diff --git a/library/std/src/sys_common/wtf8.rs b/library/std/src/sys_common/wtf8.rs deleted file mode 100644 index 50bde88b5a4..00000000000 --- a/library/std/src/sys_common/wtf8.rs +++ /dev/null @@ -1,1083 +0,0 @@ -//! Implementation of [the WTF-8 encoding](https://simonsapin.github.io/wtf-8/). -//! -//! This library uses Rust’s type system to maintain -//! [well-formedness](https://simonsapin.github.io/wtf-8/#well-formed), -//! like the `String` and `&str` types do for UTF-8. -//! -//! Since [WTF-8 must not be used -//! for interchange](https://simonsapin.github.io/wtf-8/#intended-audience), -//! this library deliberately does not provide access to the underlying bytes -//! of WTF-8 strings, -//! nor can it decode WTF-8 from arbitrary bytes. -//! WTF-8 strings can be obtained from UTF-8, UTF-16, or code points. - -// this module is imported from @SimonSapin's repo and has tons of dead code on -// unix (it's mostly used on windows), so don't worry about dead code here. -#![allow(dead_code)] - -#[cfg(test)] -mod tests; - -use core::char::{MAX_LEN_UTF8, MAX_LEN_UTF16, encode_utf8_raw, encode_utf16_raw}; -use core::clone::CloneToUninit; -use core::str::next_code_point; - -use crate::borrow::Cow; -use crate::collections::TryReserveError; -use crate::hash::{Hash, Hasher}; -use crate::iter::FusedIterator; -use crate::rc::Rc; -use crate::sync::Arc; -use crate::sys_common::AsInner; -use crate::{fmt, mem, ops, slice, str}; - -const UTF8_REPLACEMENT_CHARACTER: &str = "\u{FFFD}"; - -/// A Unicode code point: from U+0000 to U+10FFFF. -/// -/// Compares with the `char` type, -/// which represents a Unicode scalar value: -/// a code point that is not a surrogate (U+D800 to U+DFFF). -#[derive(Eq, PartialEq, Ord, PartialOrd, Clone, Copy)] -pub struct CodePoint { - value: u32, -} - -/// Format the code point as `U+` followed by four to six hexadecimal digits. -/// Example: `U+1F4A9` -impl fmt::Debug for CodePoint { - #[inline] - fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result { - write!(formatter, "U+{:04X}", self.value) - } -} - -impl CodePoint { - /// Unsafely creates a new `CodePoint` without checking the value. - /// - /// Only use when `value` is known to be less than or equal to 0x10FFFF. - #[inline] - pub unsafe fn from_u32_unchecked(value: u32) -> CodePoint { - CodePoint { value } - } - - /// Creates a new `CodePoint` if the value is a valid code point. - /// - /// Returns `None` if `value` is above 0x10FFFF. - #[inline] - pub fn from_u32(value: u32) -> Option<CodePoint> { - match value { - 0..=0x10FFFF => Some(CodePoint { value }), - _ => None, - } - } - - /// Creates a new `CodePoint` from a `char`. - /// - /// Since all Unicode scalar values are code points, this always succeeds. - #[inline] - pub fn from_char(value: char) -> CodePoint { - CodePoint { value: value as u32 } - } - - /// Returns the numeric value of the code point. - #[inline] - pub fn to_u32(&self) -> u32 { - self.value - } - - /// Returns the numeric value of the code point if it is a leading surrogate. - #[inline] - pub fn to_lead_surrogate(&self) -> Option<u16> { - match self.value { - lead @ 0xD800..=0xDBFF => Some(lead as u16), - _ => None, - } - } - - /// Returns the numeric value of the code point if it is a trailing surrogate. - #[inline] - pub fn to_trail_surrogate(&self) -> Option<u16> { - match self.value { - trail @ 0xDC00..=0xDFFF => Some(trail as u16), - _ => None, - } - } - - /// Optionally returns a Unicode scalar value for the code point. - /// - /// Returns `None` if the code point is a surrogate (from U+D800 to U+DFFF). - #[inline] - pub fn to_char(&self) -> Option<char> { - match self.value { - 0xD800..=0xDFFF => None, - _ => Some(unsafe { char::from_u32_unchecked(self.value) }), - } - } - - /// Returns a Unicode scalar value for the code point. - /// - /// Returns `'\u{FFFD}'` (the replacement character “�”) - /// if the code point is a surrogate (from U+D800 to U+DFFF). - #[inline] - pub fn to_char_lossy(&self) -> char { - self.to_char().unwrap_or('\u{FFFD}') - } -} - -/// An owned, growable string of well-formed WTF-8 data. -/// -/// Similar to `String`, but can additionally contain surrogate code points -/// if they’re not in a surrogate pair. -#[derive(Eq, PartialEq, Ord, PartialOrd, Clone)] -pub struct Wtf8Buf { - bytes: Vec<u8>, - - /// Do we know that `bytes` holds a valid UTF-8 encoding? We can easily - /// know this if we're constructed from a `String` or `&str`. - /// - /// It is possible for `bytes` to have valid UTF-8 without this being - /// set, such as when we're concatenating `&Wtf8`'s and surrogates become - /// paired, as we don't bother to rescan the entire string. - is_known_utf8: bool, -} - -impl ops::Deref for Wtf8Buf { - type Target = Wtf8; - - fn deref(&self) -> &Wtf8 { - self.as_slice() - } -} - -impl ops::DerefMut for Wtf8Buf { - fn deref_mut(&mut self) -> &mut Wtf8 { - self.as_mut_slice() - } -} - -/// 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. -/// -/// For example, the code units [U+0061, U+D800, U+000A] are formatted as -/// `"a\u{D800}\n"`. -impl fmt::Debug for Wtf8Buf { - #[inline] - fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result { - fmt::Debug::fmt(&**self, formatter) - } -} - -/// Formats the string with unpaired surrogates substituted with the replacement -/// character, U+FFFD. -impl fmt::Display for Wtf8Buf { - fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result { - if let Some(s) = self.as_known_utf8() { - fmt::Display::fmt(s, formatter) - } else { - fmt::Display::fmt(&**self, formatter) - } - } -} - -impl Wtf8Buf { - /// Creates a new, empty WTF-8 string. - #[inline] - pub fn new() -> Wtf8Buf { - Wtf8Buf { bytes: Vec::new(), is_known_utf8: true } - } - - /// Creates a new, empty WTF-8 string with pre-allocated capacity for `capacity` bytes. - #[inline] - pub fn with_capacity(capacity: usize) -> Wtf8Buf { - Wtf8Buf { bytes: Vec::with_capacity(capacity), is_known_utf8: true } - } - - /// Creates a WTF-8 string from a WTF-8 byte vec. - /// - /// Since the byte vec is not checked for valid WTF-8, this function is - /// marked unsafe. - #[inline] - pub unsafe fn from_bytes_unchecked(value: Vec<u8>) -> Wtf8Buf { - Wtf8Buf { bytes: value, is_known_utf8: false } - } - - /// Creates a WTF-8 string from a UTF-8 `String`. - /// - /// This takes ownership of the `String` and does not copy. - /// - /// Since WTF-8 is a superset of UTF-8, this always succeeds. - #[inline] - pub const fn from_string(string: String) -> Wtf8Buf { - Wtf8Buf { bytes: string.into_bytes(), is_known_utf8: true } - } - - /// Creates a WTF-8 string from a UTF-8 `&str` slice. - /// - /// This copies the content of the slice. - /// - /// Since WTF-8 is a superset of UTF-8, this always succeeds. - #[inline] - pub fn from_str(s: &str) -> Wtf8Buf { - Wtf8Buf { bytes: s.as_bytes().to_vec(), is_known_utf8: true } - } - - pub fn clear(&mut self) { - self.bytes.clear(); - self.is_known_utf8 = true; - } - - /// Creates a WTF-8 string from a potentially ill-formed UTF-16 slice of 16-bit code units. - /// - /// This is lossless: calling `.encode_wide()` on the resulting string - /// will always return the original code units. - pub fn from_wide(v: &[u16]) -> Wtf8Buf { - let mut string = Wtf8Buf::with_capacity(v.len()); - for item in char::decode_utf16(v.iter().cloned()) { - match item { - Ok(ch) => string.push_char(ch), - Err(surrogate) => { - let surrogate = surrogate.unpaired_surrogate(); - // Surrogates are known to be in the code point range. - let code_point = unsafe { CodePoint::from_u32_unchecked(surrogate as u32) }; - // The string will now contain an unpaired surrogate. - string.is_known_utf8 = false; - // Skip the WTF-8 concatenation check, - // surrogate pairs are already decoded by decode_utf16 - string.push_code_point_unchecked(code_point); - } - } - } - string - } - - /// Appends the given `char` to the end of this string. - /// This does **not** include the WTF-8 concatenation check or `is_known_utf8` check. - /// Copied from String::push. - fn push_code_point_unchecked(&mut self, code_point: CodePoint) { - let mut bytes = [0; MAX_LEN_UTF8]; - let bytes = encode_utf8_raw(code_point.value, &mut bytes); - self.bytes.extend_from_slice(bytes) - } - - #[inline] - pub fn as_slice(&self) -> &Wtf8 { - unsafe { Wtf8::from_bytes_unchecked(&self.bytes) } - } - - #[inline] - pub fn as_mut_slice(&mut self) -> &mut Wtf8 { - // Safety: `Wtf8` doesn't expose any way to mutate the bytes that would - // cause them to change from well-formed UTF-8 to ill-formed UTF-8, - // which would break the assumptions of the `is_known_utf8` field. - unsafe { Wtf8::from_mut_bytes_unchecked(&mut self.bytes) } - } - - /// Converts the string to UTF-8 without validation, if it was created from - /// valid UTF-8. - #[inline] - fn as_known_utf8(&self) -> Option<&str> { - if self.is_known_utf8 { - // SAFETY: The buffer is known to be valid UTF-8. - Some(unsafe { str::from_utf8_unchecked(self.as_bytes()) }) - } else { - None - } - } - - /// Reserves capacity for at least `additional` more bytes to be inserted - /// in the given `Wtf8Buf`. - /// The collection may reserve more space to avoid frequent reallocations. - /// - /// # Panics - /// - /// Panics if the new capacity exceeds `isize::MAX` bytes. - #[inline] - pub fn reserve(&mut self, additional: usize) { - self.bytes.reserve(additional) - } - - /// Tries to reserve capacity for at least `additional` more bytes to be - /// inserted in the given `Wtf8Buf`. The `Wtf8Buf` may reserve more space to - /// avoid frequent reallocations. After calling `try_reserve`, capacity will - /// be greater than or equal to `self.len() + additional`. Does nothing if - /// capacity is already sufficient. This method preserves the contents even - /// if an error occurs. - /// - /// # Errors - /// - /// If the capacity overflows, or the allocator reports a failure, then an error - /// is returned. - #[inline] - pub fn try_reserve(&mut self, additional: usize) -> Result<(), TryReserveError> { - self.bytes.try_reserve(additional) - } - - #[inline] - pub fn reserve_exact(&mut self, additional: usize) { - self.bytes.reserve_exact(additional) - } - - /// Tries to reserve the minimum capacity for exactly `additional` more - /// bytes to be inserted in the given `Wtf8Buf`. After calling - /// `try_reserve_exact`, capacity will be greater than or equal to - /// `self.len() + additional` if it returns `Ok(())`. - /// Does nothing if the capacity is already sufficient. - /// - /// Note that the allocator may give the `Wtf8Buf` more space than it - /// requests. Therefore, capacity can not be relied upon to be precisely - /// minimal. Prefer [`try_reserve`] if future insertions are expected. - /// - /// [`try_reserve`]: Wtf8Buf::try_reserve - /// - /// # Errors - /// - /// If the capacity overflows, or the allocator reports a failure, then an error - /// is returned. - #[inline] - pub fn try_reserve_exact(&mut self, additional: usize) -> Result<(), TryReserveError> { - self.bytes.try_reserve_exact(additional) - } - - #[inline] - pub fn shrink_to_fit(&mut self) { - self.bytes.shrink_to_fit() - } - - #[inline] - pub fn shrink_to(&mut self, min_capacity: usize) { - self.bytes.shrink_to(min_capacity) - } - - #[inline] - pub fn leak<'a>(self) -> &'a mut Wtf8 { - unsafe { Wtf8::from_mut_bytes_unchecked(self.bytes.leak()) } - } - - /// Returns the number of bytes that this string buffer can hold without reallocating. - #[inline] - pub fn capacity(&self) -> usize { - self.bytes.capacity() - } - - /// Append a UTF-8 slice at the end of the string. - #[inline] - pub fn push_str(&mut self, other: &str) { - self.bytes.extend_from_slice(other.as_bytes()) - } - - /// Append a WTF-8 slice 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_wtf8(&mut self, other: &Wtf8) { - match ((&*self).final_lead_surrogate(), other.initial_trail_surrogate()) { - // Replace newly paired surrogates by a supplementary code point. - (Some(lead), Some(trail)) => { - let len_without_lead_surrogate = self.len() - 3; - 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()); - 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. - 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) } - } -} |