copy_stack_vec/vec/array/
split_off.rs

1// This file is part of copy-stack-vec.
2// SPDX-License-Identifier: MIT OR Apache-2.0
3
4// Crate imports
5use crate::{error::Error, vec::CopyStackVec};
6
7impl<T: Copy + Default, const N: usize> CopyStackVec<T, N> {
8    /// Splits the vector into two at index `at`.
9    ///
10    /// On success:
11    /// - `self` is left containing the prefix `[0..at)`,
12    /// - the returned vector contains the tail `[at..len)`.
13    ///
14    /// Returns [`Error::OutOfBounds`] if `at > self.len()`. On error, `self`
15    /// is left unchanged.
16    #[inline]
17    pub fn split_off(&mut self, at: usize) -> Result<Self, Error> {
18        let len = self.len;
19        if at > len {
20            return Err(Error::OutOfBounds);
21        }
22
23        let tail_len = len - at;
24        let mut other: CopyStackVec<T, N> = CopyStackVec::default();
25
26        if tail_len > 0 {
27            // This must fit by construction: tail_len <= len <= N and other is empty.
28            // We still propagate any error instead of panicking.
29            other.extend_from_slice(&self.as_slice()[at..len])?;
30        }
31
32        // Shrink self to the prefix.
33        self.len = at;
34
35        Ok(other)
36    }
37}
copy_stack_vec/vec/array/split_off.rs

copy_stack_vec/vec/array/
split_off.rs
