/rust/registry/src/index.crates.io-1949cf8c6b5b557f/potential_utf-0.1.3/src/ustr.rs

Source
// This file is part of ICU4X. For terms of use, please see the file
// called LICENSE at the top level of the ICU4X source tree
// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).

#[cfg(feature = "alloc")]
use alloc::boxed::Box;
use core::cmp::Ordering;
use core::fmt;
use core::ops::Deref;

/// A byte slice that is expected to be a UTF-8 string but does not enforce that invariant.
///
/// Use this type instead of `str` if you don't need to enforce UTF-8 during deserialization. For
/// example, strings that are keys of a map don't need to ever be reified as `str`s.
///
/// [`PotentialUtf8`] derefs to `[u8]`. To obtain a `str`, use [`Self::try_as_str()`].
///
/// The main advantage of this type over `[u8]` is that it serializes as a string in
/// human-readable formats like JSON.
///
/// # Examples
///
/// Using an [`PotentialUtf8`] as the key of a [`ZeroMap`]:
///
/// ```
/// use potential_utf::PotentialUtf8;
/// use zerovec::ZeroMap;
///
/// // This map is cheap to deserialize, as we don't need to perform UTF-8 validation.
/// let map: ZeroMap<PotentialUtf8, u8> = [
///     (PotentialUtf8::from_bytes(b"abc"), 11),
///     (PotentialUtf8::from_bytes(b"def"), 22),
///     (PotentialUtf8::from_bytes(b"ghi"), 33),
/// ]
/// .into_iter()
/// .collect();
///
/// let key = "abc";
/// let value = map.get_copied(PotentialUtf8::from_str(key));
/// assert_eq!(Some(11), value);
/// ```
///
/// [`ZeroMap`]: zerovec::ZeroMap
#[repr(transparent)]
#[derive(PartialEq, Eq, PartialOrd, Ord)]
#[allow(clippy::exhaustive_structs)] // transparent newtype
pub struct PotentialUtf8(pub [u8]);

impl fmt::Debug for PotentialUtf8 {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        // Debug as a string if possible
        match self.try_as_str() {
            Ok(s) => fmt::Debug::fmt(s, f),
            Err(_) => fmt::Debug::fmt(&self.0, f),
        }
    }
}

impl PotentialUtf8 {
    /// Create a [`PotentialUtf8`] from a byte slice.
    #[inline]
    pub const fn from_bytes(other: &[u8]) -> &Self {
        // Safety: PotentialUtf8 is transparent over [u8]
        unsafe { core::mem::transmute(other) }
    }

    /// Create a [`PotentialUtf8`] from a string slice.
    #[inline]
    pub const fn from_str(s: &str) -> &Self {
        Self::from_bytes(s.as_bytes())
    }

    /// Create a [`PotentialUtf8`] from boxed bytes.
    #[inline]
    #[cfg(feature = "alloc")]
    pub fn from_boxed_bytes(other: Box<[u8]>) -> Box<Self> {
        // Safety: PotentialUtf8 is transparent over [u8]
        unsafe { core::mem::transmute(other) }
    }

    /// Create a [`PotentialUtf8`] from a boxed `str`.
    #[inline]
    #[cfg(feature = "alloc")]
    pub fn from_boxed_str(other: Box<str>) -> Box<Self> {
        Self::from_boxed_bytes(other.into_boxed_bytes())
    }

    /// Get the bytes from a [`PotentialUtf8].
    #[inline]
    pub const fn as_bytes(&self) -> &[u8] {
        &self.0
    }

    /// Attempt to convert a [`PotentialUtf8`] to a `str`.
    ///
    /// # Examples
    ///
    /// ```
    /// use potential_utf::PotentialUtf8;
    ///
    /// static A: &PotentialUtf8 = PotentialUtf8::from_bytes(b"abc");
    ///
    /// let b = A.try_as_str().unwrap();
    /// assert_eq!(b, "abc");
    /// ```
    // Note: this is const starting in 1.63
    #[inline]
    pub fn try_as_str(&self) -> Result<&str, core::str::Utf8Error> {
        core::str::from_utf8(&self.0)
    }
}

impl<'a> From<&'a str> for &'a PotentialUtf8 {
    #[inline]
    fn from(other: &'a str) -> Self {
        PotentialUtf8::from_str(other)
    }
}

impl PartialEq<str> for PotentialUtf8 {
    fn eq(&self, other: &str) -> bool {
        self.eq(Self::from_str(other))
    }
}

impl PartialOrd<str> for PotentialUtf8 {
    fn partial_cmp(&self, other: &str) -> Option<Ordering> {
        self.partial_cmp(Self::from_str(other))
    }
}

impl PartialEq<PotentialUtf8> for str {
    fn eq(&self, other: &PotentialUtf8) -> bool {
        PotentialUtf8::from_str(self).eq(other)
    }
}

impl PartialOrd<PotentialUtf8> for str {
    fn partial_cmp(&self, other: &PotentialUtf8) -> Option<Ordering> {
        PotentialUtf8::from_str(self).partial_cmp(other)
    }
}

#[cfg(feature = "alloc")]
impl From<Box<str>> for Box<PotentialUtf8> {
    #[inline]
    fn from(other: Box<str>) -> Self {
        PotentialUtf8::from_boxed_str(other)
    }
}

impl Deref for PotentialUtf8 {
    type Target = [u8];
    fn deref(&self) -> &Self::Target {
        &self.0
    }
}

/// This impl requires enabling the optional `zerovec` Cargo feature
#[cfg(all(feature = "zerovec", feature = "alloc"))]
impl<'a> zerovec::maps::ZeroMapKV<'a> for PotentialUtf8 {
    type Container = zerovec::VarZeroVec<'a, PotentialUtf8>;
    type Slice = zerovec::VarZeroSlice<PotentialUtf8>;
    type GetType = PotentialUtf8;
    type OwnedType = Box<PotentialUtf8>;
}

// Safety (based on the safety checklist on the VarULE trait):
//  1. PotentialUtf8 does not include any uninitialized or padding bytes (transparent over a ULE)
//  2. PotentialUtf8 is aligned to 1 byte (transparent over a ULE)
//  3. The impl of `validate_bytes()` returns an error if any byte is not valid (impossible)
//  4. The impl of `validate_bytes()` returns an error if the slice cannot be used in its entirety (impossible)
//  5. The impl of `from_bytes_unchecked()` returns a reference to the same data (returns the argument directly)
//  6. All other methods are defaulted
//  7. `[T]` byte equality is semantic equality (transparent over a ULE)
/// This impl requires enabling the optional `zerovec` Cargo feature
#[cfg(feature = "zerovec")]
unsafe impl zerovec::ule::VarULE for PotentialUtf8 {
    #[inline]
    fn validate_bytes(_: &[u8]) -> Result<(), zerovec::ule::UleError> {
        Ok(())
    }
    #[inline]
    unsafe fn from_bytes_unchecked(bytes: &[u8]) -> &Self {
        PotentialUtf8::from_bytes(bytes)
    }
}

/// This impl requires enabling the optional `serde` Cargo feature
#[cfg(feature = "serde")]
impl serde::Serialize for PotentialUtf8 {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: serde::Serializer,
    {
        use serde::ser::Error;
        let s = self
            .try_as_str()
            .map_err(|_| S::Error::custom("invalid UTF-8 in PotentialUtf8"))?;
        if serializer.is_human_readable() {
            serializer.serialize_str(s)
        } else {
            serializer.serialize_bytes(s.as_bytes())
        }
    }
}

/// This impl requires enabling the optional `serde` Cargo feature
#[cfg(all(feature = "serde", feature = "alloc"))]
impl<'de> serde::Deserialize<'de> for Box<PotentialUtf8> {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: serde::Deserializer<'de>,
    {
        if deserializer.is_human_readable() {
            let boxed_str = Box::<str>::deserialize(deserializer)?;
            Ok(PotentialUtf8::from_boxed_str(boxed_str))
        } else {
            let boxed_bytes = Box::<[u8]>::deserialize(deserializer)?;
            Ok(PotentialUtf8::from_boxed_bytes(boxed_bytes))
        }
    }
}

/// This impl requires enabling the optional `serde` Cargo feature
#[cfg(feature = "serde")]
impl<'de, 'a> serde::Deserialize<'de> for &'a PotentialUtf8
where
    'de: 'a,
{
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: serde::Deserializer<'de>,
    {
        if deserializer.is_human_readable() {
            let s = <&str>::deserialize(deserializer)?;
            Ok(PotentialUtf8::from_str(s))
        } else {
            let bytes = <&[u8]>::deserialize(deserializer)?;
            Ok(PotentialUtf8::from_bytes(bytes))
        }
    }
}

#[repr(transparent)]
#[derive(PartialEq, Eq, PartialOrd, Ord)]
#[allow(clippy::exhaustive_structs)] // transparent newtype
pub struct PotentialUtf16(pub [u16]);

impl fmt::Debug for PotentialUtf16 {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        // Debug as a string if possible
        for c in char::decode_utf16(self.0.iter().copied()) {
            match c {
                Ok(c) => write!(f, "{c}")?,
                Err(e) => write!(f, "\\0x{:x}", e.unpaired_surrogate())?,
            }
        }
        Ok(())
    }
}

impl PotentialUtf16 {
    /// Create a [`PotentialUtf16`] from a u16 slice.
    #[inline]
    pub const fn from_slice(other: &[u16]) -> &Self {
        // Safety: PotentialUtf16 is transparent over [u16]
        unsafe { core::mem::transmute(other) }
    }

    pub fn chars(&self) -> impl Iterator<Item = char> + '_ {
        char::decode_utf16(self.0.iter().copied()).map(|c| c.unwrap_or(char::REPLACEMENT_CHARACTER))
    }
}

Coverage Report

Created: 2025-10-28 06:23

Line	Count	Source
1		// This file is part of ICU4X. For terms of use, please see the file
2		// called LICENSE at the top level of the ICU4X source tree
3		// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
4
5		#[cfg(feature = "alloc")]
6		use alloc::boxed::Box;
7		use core::cmp::Ordering;
8		use core::fmt;
9		use core::ops::Deref;
10
11		/// A byte slice that is expected to be a UTF-8 string but does not enforce that invariant.
12		///
13		/// Use this type instead of `str` if you don't need to enforce UTF-8 during deserialization. For
14		/// example, strings that are keys of a map don't need to ever be reified as `str`s.
15		///
16		/// [`PotentialUtf8`] derefs to `[u8]`. To obtain a `str`, use [`Self::try_as_str()`].
17		///
18		/// The main advantage of this type over `[u8]` is that it serializes as a string in
19		/// human-readable formats like JSON.
20		///
21		/// # Examples
22		///
23		/// Using an [`PotentialUtf8`] as the key of a [`ZeroMap`]:
24		///
25		/// ```
26		/// use potential_utf::PotentialUtf8;
27		/// use zerovec::ZeroMap;
28		///
29		/// // This map is cheap to deserialize, as we don't need to perform UTF-8 validation.
30		/// let map: ZeroMap<PotentialUtf8, u8> = [
31		/// (PotentialUtf8::from_bytes(b"abc"), 11),
32		/// (PotentialUtf8::from_bytes(b"def"), 22),
33		/// (PotentialUtf8::from_bytes(b"ghi"), 33),
34		/// ]
35		/// .into_iter()
36		/// .collect();
37		///
38		/// let key = "abc";
39		/// let value = map.get_copied(PotentialUtf8::from_str(key));
40		/// assert_eq!(Some(11), value);
41		/// ```
42		///
43		/// [`ZeroMap`]: zerovec::ZeroMap
44		#[repr(transparent)]
45		#[derive(PartialEq, Eq, PartialOrd, Ord)]
46		#[allow(clippy::exhaustive_structs)] // transparent newtype
47		pub struct PotentialUtf8(pub [u8]);
48
49		impl fmt::Debug for PotentialUtf8 {
50	0	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
51		// Debug as a string if possible
52	0	match self.try_as_str() {
53	0	Ok(s) => fmt::Debug::fmt(s, f),
54	0	Err(_) => fmt::Debug::fmt(&self.0, f),
55		}
56	0	}
57		}
58
59		impl PotentialUtf8 {
60		/// Create a [`PotentialUtf8`] from a byte slice.
61		#[inline]
62	0	pub const fn from_bytes(other: &[u8]) -> &Self {
63		// Safety: PotentialUtf8 is transparent over [u8]
64	0	unsafe { core::mem::transmute(other) }
65	0	}
66
67		/// Create a [`PotentialUtf8`] from a string slice.
68		#[inline]
69	0	pub const fn from_str(s: &str) -> &Self {
70	0	Self::from_bytes(s.as_bytes())
71	0	}
72
73		/// Create a [`PotentialUtf8`] from boxed bytes.
74		#[inline]
75		#[cfg(feature = "alloc")]
76		pub fn from_boxed_bytes(other: Box<[u8]>) -> Box<Self> {
77		// Safety: PotentialUtf8 is transparent over [u8]
78		unsafe { core::mem::transmute(other) }
79		}
80
81		/// Create a [`PotentialUtf8`] from a boxed `str`.
82		#[inline]
83		#[cfg(feature = "alloc")]
84		pub fn from_boxed_str(other: Box<str>) -> Box<Self> {
85		Self::from_boxed_bytes(other.into_boxed_bytes())
86		}
87
88		/// Get the bytes from a [`PotentialUtf8].
89		#[inline]
90	0	pub const fn as_bytes(&self) -> &[u8] {
91	0	&self.0
92	0	}
93
94		/// Attempt to convert a [`PotentialUtf8`] to a `str`.
95		///
96		/// # Examples
97		///
98		/// ```
99		/// use potential_utf::PotentialUtf8;
100		///
101		/// static A: &PotentialUtf8 = PotentialUtf8::from_bytes(b"abc");
102		///
103		/// let b = A.try_as_str().unwrap();
104		/// assert_eq!(b, "abc");
105		/// ```
106		// Note: this is const starting in 1.63
107		#[inline]
108	0	pub fn try_as_str(&self) -> Result<&str, core::str::Utf8Error> {
109	0	core::str::from_utf8(&self.0)
110	0	}
111		}
112
113		impl<'a> From<&'a str> for &'a PotentialUtf8 {
114		#[inline]
115	0	fn from(other: &'a str) -> Self {
116	0	PotentialUtf8::from_str(other)
117	0	}
118		}
119
120		impl PartialEq<str> for PotentialUtf8 {
121	0	fn eq(&self, other: &str) -> bool {
122	0	self.eq(Self::from_str(other))
123	0	}
124		}
125
126		impl PartialOrd<str> for PotentialUtf8 {
127	0	fn partial_cmp(&self, other: &str) -> Option<Ordering> {
128	0	self.partial_cmp(Self::from_str(other))
129	0	}
130		}
131
132		impl PartialEq<PotentialUtf8> for str {
133	0	fn eq(&self, other: &PotentialUtf8) -> bool {
134	0	PotentialUtf8::from_str(self).eq(other)
135	0	}
136		}
137
138		impl PartialOrd<PotentialUtf8> for str {
139	0	fn partial_cmp(&self, other: &PotentialUtf8) -> Option<Ordering> {
140	0	PotentialUtf8::from_str(self).partial_cmp(other)
141	0	}
142		}
143
144		#[cfg(feature = "alloc")]
145		impl From<Box<str>> for Box<PotentialUtf8> {
146		#[inline]
147		fn from(other: Box<str>) -> Self {
148		PotentialUtf8::from_boxed_str(other)
149		}
150		}
151
152		impl Deref for PotentialUtf8 {
153		type Target = [u8];
154	0	fn deref(&self) -> &Self::Target {
155	0	&self.0
156	0	}
157		}
158
159		/// This impl requires enabling the optional `zerovec` Cargo feature
160		#[cfg(all(feature = "zerovec", feature = "alloc"))]
161		impl<'a> zerovec::maps::ZeroMapKV<'a> for PotentialUtf8 {
162		type Container = zerovec::VarZeroVec<'a, PotentialUtf8>;
163		type Slice = zerovec::VarZeroSlice<PotentialUtf8>;
164		type GetType = PotentialUtf8;
165		type OwnedType = Box<PotentialUtf8>;
166		}
167
168		// Safety (based on the safety checklist on the VarULE trait):
169		// 1. PotentialUtf8 does not include any uninitialized or padding bytes (transparent over a ULE)
170		// 2. PotentialUtf8 is aligned to 1 byte (transparent over a ULE)
171		// 3. The impl of `validate_bytes()` returns an error if any byte is not valid (impossible)
172		// 4. The impl of `validate_bytes()` returns an error if the slice cannot be used in its entirety (impossible)
173		// 5. The impl of `from_bytes_unchecked()` returns a reference to the same data (returns the argument directly)
174		// 6. All other methods are defaulted
175		// 7. `[T]` byte equality is semantic equality (transparent over a ULE)
176		/// This impl requires enabling the optional `zerovec` Cargo feature
177		#[cfg(feature = "zerovec")]
178		unsafe impl zerovec::ule::VarULE for PotentialUtf8 {
179		#[inline]
180	0	fn validate_bytes(_: &[u8]) -> Result<(), zerovec::ule::UleError> {
181	0	Ok(())
182	0	}
183		#[inline]
184	0	unsafe fn from_bytes_unchecked(bytes: &[u8]) -> &Self {
185	0	PotentialUtf8::from_bytes(bytes)
186	0	}
187		}
188
189		/// This impl requires enabling the optional `serde` Cargo feature
190		#[cfg(feature = "serde")]
191		impl serde::Serialize for PotentialUtf8 {
192		fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
193		where
194		S: serde::Serializer,
195		{
196		use serde::ser::Error;
197		let s = self
198		.try_as_str()
199		.map_err(\|_\| S::Error::custom("invalid UTF-8 in PotentialUtf8"))?;
200		if serializer.is_human_readable() {
201		serializer.serialize_str(s)
202		} else {
203		serializer.serialize_bytes(s.as_bytes())
204		}
205		}
206		}
207
208		/// This impl requires enabling the optional `serde` Cargo feature
209		#[cfg(all(feature = "serde", feature = "alloc"))]
210		impl<'de> serde::Deserialize<'de> for Box<PotentialUtf8> {
211		fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
212		where
213		D: serde::Deserializer<'de>,
214		{
215		if deserializer.is_human_readable() {
216		let boxed_str = Box::<str>::deserialize(deserializer)?;
217		Ok(PotentialUtf8::from_boxed_str(boxed_str))
218		} else {
219		let boxed_bytes = Box::<[u8]>::deserialize(deserializer)?;
220		Ok(PotentialUtf8::from_boxed_bytes(boxed_bytes))
221		}
222		}
223		}
224
225		/// This impl requires enabling the optional `serde` Cargo feature
226		#[cfg(feature = "serde")]
227		impl<'de, 'a> serde::Deserialize<'de> for &'a PotentialUtf8
228		where
229		'de: 'a,
230		{
231		fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
232		where
233		D: serde::Deserializer<'de>,
234		{
235		if deserializer.is_human_readable() {
236		let s = <&str>::deserialize(deserializer)?;
237		Ok(PotentialUtf8::from_str(s))
238		} else {
239		let bytes = <&[u8]>::deserialize(deserializer)?;
240		Ok(PotentialUtf8::from_bytes(bytes))
241		}
242		}
243		}
244
245		#[repr(transparent)]
246		#[derive(PartialEq, Eq, PartialOrd, Ord)]
247		#[allow(clippy::exhaustive_structs)] // transparent newtype
248		pub struct PotentialUtf16(pub [u16]);
249
250		impl fmt::Debug for PotentialUtf16 {
251	0	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
252		// Debug as a string if possible
253	0	for c in char::decode_utf16(self.0.iter().copied()) {
254	0	match c {
255	0	Ok(c) => write!(f, "{c}")?,
256	0	Err(e) => write!(f, "\\0x{:x}", e.unpaired_surrogate())?,
257		}
258		}
259	0	Ok(())
260	0	}
261		}
262
263		impl PotentialUtf16 {
264		/// Create a [`PotentialUtf16`] from a u16 slice.
265		#[inline]
266	0	pub const fn from_slice(other: &[u16]) -> &Self {
267		// Safety: PotentialUtf16 is transparent over [u16]
268	0	unsafe { core::mem::transmute(other) }
269	0	}
270
271	0	pub fn chars(&self) -> impl Iterator<Item = char> + '_ {
272	0	char::decode_utf16(self.0.iter().copied()).map(\|c\| c.unwrap_or(char::REPLACEMENT_CHARACTER))
273	0	}
274		}