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//! 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::{encode_utf16_raw, encode_utf8_raw};
use core::str::next_code_point;
use crate::borrow::Cow;
use crate::collections::TryReserveError;
use crate::fmt;
use crate::hash::{Hash, Hasher};
use crate::iter::FusedIterator;
use crate::mem;
use crate::ops;
use crate::rc::Rc;
use crate::slice;
use crate::str;
use crate::sync::Arc;
use crate::sys_common::AsInner;
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()
}
}
/// Format the string with double quotes,
/// and surrogates as `\u` followed by four hexadecimal digits.
/// Example: `"a\u{D800}"` for a string with code points [U+0061, U+D800]
impl fmt::Debug for Wtf8Buf {
#[inline]
fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Debug::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 functions 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 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(str: &str) -> Wtf8Buf {
Wtf8Buf { bytes: <[_]>::to_vec(str.as_bytes()), 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
}
/// Copied from String::push
/// This does **not** include the WTF-8 concatenation check or `is_known_utf8` check.
fn push_code_point_unchecked(&mut self, code_point: CodePoint) {
let mut bytes = [0; 4];
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) }
}
/// 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 overflows `usize`.
#[inline]
pub fn reserve(&mut self, additional: usize) {
self.bytes.reserve(additional)
}
/// Tries to reserve capacity for at least `additional` more length units
/// 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`
/// length units 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)
}
/// 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 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 {
// Fast path: If we already have UTF-8, we can return it immediately.
if self.is_known_utf8 {
return unsafe { String::from_utf8_unchecked(self.bytes) };
}
let mut pos = 0;
loop {
match self.next_surrogate(pos) {
Some((surrogate_pos, _)) => {
pos = surrogate_pos + 3;
self.bytes[surrogate_pos..pos]
.copy_from_slice(UTF8_REPLACEMENT_CHARACTER.as_bytes());
}
None => return 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 }
}
}
/// 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
}
}
/// Format the slice with double quotes,
/// and surrogates as `\u` followed by four hexadecimal digits.
/// Example: `"a\u{D800}"` for a slice with code points [U+0061, U+D800]
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("\"")
}
}
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 {
mem::transmute(value)
}
/// 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 {
mem::transmute(value)
}
/// 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 surrogate_pos = match self.next_surrogate(0) {
None => return Cow::Borrowed(unsafe { str::from_utf8_unchecked(&self.bytes) }),
Some((pos, _)) => pos,
};
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 core::str::StrPrelude::is_char_boundary
#[inline]
pub fn is_code_point_boundary(slice: &Wtf8, index: usize) -> bool {
if index == slice.len() {
return true;
}
match slice.bytes.get(index) {
None => false,
Some(&b) => b < 128 || b >= 192,
}
}
/// Copied from core::str::raw::slice_unchecked
#[inline]
pub unsafe fn slice_unchecked(s: &Wtf8, begin: usize, end: usize) -> &Wtf8 {
// memory layout of a &[u8] and &Wtf8 are the same
Wtf8::from_bytes_unchecked(slice::from_raw_parts(s.bytes.as_ptr().add(begin), end - begin))
}
/// 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<'a> Iterator for Wtf8CodePoints<'a> {
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<'a> Iterator for EncodeWide<'a> {
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; 2];
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)
}
}