Merging upstream version 1.67.1+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 103 insertions, 0 deletions

diff --git a/vendor/zerovec/src/ule/slices.rs b/vendor/zerovec/src/ule/slices.rs
new file mode 100644
index 000000000..75ea57e02
--- /dev/null
+++ b/vendor/zerovec/src/ule/slices.rs
@@ -0,0 +1,103 @@
+// 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 ).
+
+use crate::ule::*;
+use core::str;
+
+// Safety (based on the safety checklist on the ULE trait):
+//  1. [T; N] does not include any uninitialized or padding bytes since T is ULE
+//  2. [T; N] is aligned to 1 byte since T is ULE
+//  3. The impl of validate_byte_slice() returns an error if any byte is not valid.
+//  4. The impl of validate_byte_slice() returns an error if there are leftover bytes.
+//  5. The other ULE methods use the default impl.
+//  6. [T; N] byte equality is semantic equality since T is ULE
+unsafe impl<T: ULE, const N: usize> ULE for [T; N] {
+    #[inline]
+    fn validate_byte_slice(bytes: &[u8]) -> Result<(), ZeroVecError> {
+        // a slice of multiple Selfs is equivalent to just a larger slice of Ts
+        T::validate_byte_slice(bytes)
+    }
+}
+
+impl<T: AsULE, const N: usize> AsULE for [T; N] {
+    type ULE = [T::ULE; N];
+    #[inline]
+    fn to_unaligned(self) -> Self::ULE {
+        self.map(T::to_unaligned)
+    }
+    #[inline]
+    fn from_unaligned(unaligned: Self::ULE) -> Self {
+        unaligned.map(T::from_unaligned)
+    }
+}
+
+unsafe impl<T: EqULE, const N: usize> EqULE for [T; N] {}
+
+// Safety (based on the safety checklist on the VarULE trait):
+//  1. str does not include any uninitialized or padding bytes.
+//  2. str is aligned to 1 byte.
+//  3. The impl of `validate_byte_slice()` returns an error if any byte is not valid.
+//  4. The impl of `validate_byte_slice()` returns an error if the slice cannot be used in its entirety
+//  5. The impl of `from_byte_slice_unchecked()` returns a reference to the same data.
+//  6. `parse_byte_slice()` is equivalent to `validate_byte_slice()` followed by `from_byte_slice_unchecked()`
+//  7. str byte equality is semantic equality
+unsafe impl VarULE for str {
+    #[inline]
+    fn validate_byte_slice(bytes: &[u8]) -> Result<(), ZeroVecError> {
+        str::from_utf8(bytes).map_err(|_| ZeroVecError::parse::<Self>())?;
+        Ok(())
+    }
+
+    #[inline]
+    fn parse_byte_slice(bytes: &[u8]) -> Result<&Self, ZeroVecError> {
+        str::from_utf8(bytes).map_err(|_| ZeroVecError::parse::<Self>())
+    }
+    /// Invariant: must be safe to call when called on a slice that previously
+    /// succeeded with `parse_byte_slice`
+    #[inline]
+    unsafe fn from_byte_slice_unchecked(bytes: &[u8]) -> &Self {
+        str::from_utf8_unchecked(bytes)
+    }
+}
+
+/// Note: VarULE is well-defined for all `[T]` where `T: ULE`, but [`ZeroSlice`] is more ergonomic
+/// when `T` is a low-level ULE type. For example:
+///
+/// ```no_run
+/// # use zerovec::ZeroSlice;
+/// # use zerovec::VarZeroVec;
+/// # use zerovec::ule::AsULE;
+/// // OK: [u8] is a useful type
+/// let _: VarZeroVec<[u8]> = unimplemented!();
+///
+/// // Technically works, but [u32::ULE] is not very useful
+/// let _: VarZeroVec<[<u32 as AsULE>::ULE]> = unimplemented!();
+///
+/// // Better: ZeroSlice<u32>
+/// let _: VarZeroVec<ZeroSlice<u32>> = unimplemented!();
+/// ```
+///
+/// [`ZeroSlice`]: crate::ZeroSlice
+// Safety (based on the safety checklist on the VarULE trait):
+//  1. [T] does not include any uninitialized or padding bytes (achieved by being a slice of a ULE type)
+//  2. [T] is aligned to 1 byte (achieved by being a slice of a ULE type)
+//  3. The impl of `validate_byte_slice()` returns an error if any byte is not valid.
+//  4. The impl of `validate_byte_slice()` returns an error if the slice cannot be used in its entirety
+//  5. The impl of `from_byte_slice_unchecked()` returns a reference to the same data.
+//  6. All other methods are defaulted
+//  7. `[T]` byte equality is semantic equality (achieved by being a slice of a ULE type)
+unsafe impl<T> VarULE for [T]
+where
+    T: ULE,
+{
+    #[inline]
+    fn validate_byte_slice(slice: &[u8]) -> Result<(), ZeroVecError> {
+        T::validate_byte_slice(slice)
+    }
+
+    #[inline]
+    unsafe fn from_byte_slice_unchecked(bytes: &[u8]) -> &Self {
+        T::from_byte_slice_unchecked(bytes)
+    }
+}