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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
commit | 36d22d82aa202bb199967e9512281e9a53db42c9 (patch) | |
tree | 105e8c98ddea1c1e4784a60a5a6410fa416be2de /third_party/rust/arrayvec/src/arrayvec_impl.rs | |
parent | Initial commit. (diff) | |
download | firefox-esr-upstream.tar.xz firefox-esr-upstream.zip |
Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/rust/arrayvec/src/arrayvec_impl.rs')
-rw-r--r-- | third_party/rust/arrayvec/src/arrayvec_impl.rs | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/third_party/rust/arrayvec/src/arrayvec_impl.rs b/third_party/rust/arrayvec/src/arrayvec_impl.rs new file mode 100644 index 0000000000..6c09834add --- /dev/null +++ b/third_party/rust/arrayvec/src/arrayvec_impl.rs @@ -0,0 +1,86 @@ +use std::ptr; +use std::slice; + +use crate::CapacityError; + +/// Implements basic arrayvec methods - based on a few required methods +/// for length and element access. +pub(crate) trait ArrayVecImpl { + type Item; + const CAPACITY: usize; + + fn len(&self) -> usize; + + unsafe fn set_len(&mut self, new_len: usize); + + /// Return a slice containing all elements of the vector. + fn as_slice(&self) -> &[Self::Item] { + let len = self.len(); + unsafe { + slice::from_raw_parts(self.as_ptr(), len) + } + } + + /// Return a mutable slice containing all elements of the vector. + fn as_mut_slice(&mut self) -> &mut [Self::Item] { + let len = self.len(); + unsafe { + std::slice::from_raw_parts_mut(self.as_mut_ptr(), len) + } + } + + /// Return a raw pointer to the vector's buffer. + fn as_ptr(&self) -> *const Self::Item; + + /// Return a raw mutable pointer to the vector's buffer. + fn as_mut_ptr(&mut self) -> *mut Self::Item; + + fn push(&mut self, element: Self::Item) { + self.try_push(element).unwrap() + } + + fn try_push(&mut self, element: Self::Item) -> Result<(), CapacityError<Self::Item>> { + if self.len() < Self::CAPACITY { + unsafe { + self.push_unchecked(element); + } + Ok(()) + } else { + Err(CapacityError::new(element)) + } + } + + unsafe fn push_unchecked(&mut self, element: Self::Item) { + let len = self.len(); + debug_assert!(len < Self::CAPACITY); + ptr::write(self.as_mut_ptr().add(len), element); + self.set_len(len + 1); + } + + fn pop(&mut self) -> Option<Self::Item> { + if self.len() == 0 { + return None; + } + unsafe { + let new_len = self.len() - 1; + self.set_len(new_len); + Some(ptr::read(self.as_ptr().add(new_len))) + } + } + + fn clear(&mut self) { + self.truncate(0) + } + + fn truncate(&mut self, new_len: usize) { + unsafe { + let len = self.len(); + if new_len < len { + self.set_len(new_len); + let tail = slice::from_raw_parts_mut(self.as_mut_ptr().add(new_len), len - new_len); + ptr::drop_in_place(tail); + } + } + } +} + |