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// devela::sys::mem::view::slice::namespace::split
use crate::{Cmp, Slice};
/// # `*split*` API methods for subslicing.
impl<T> Slice<T> {
/* left split */
/// Returns the leftmost sub-`slice` with the given maximum `len`.
///
/// If `len > self.len()` it returns the full slice.
///
/// # Example
/// ```
/// # use devela::Slice;
/// let v = [1, 2, 3, 4, 5, 6];
/// assert_eq!(Slice::lsplit(&v, 3), &[1, 2, 3]);
/// assert_eq!(Slice::lsplit(&v, 0), &[] as &[i32]);
/// assert_eq!(Slice::lsplit(&v, 10), &[1, 2, 3, 4, 5, 6]);
/// ```
pub const fn lsplit(slice: &[T], len: usize) -> &[T] {
let end_idx = Cmp(len).clamp(0, slice.len());
let (left, _) = slice.split_at(end_idx);
left
}
/// Returns the leftmost exclusive sub-`slice` with the given maximum `len`.
///
/// If `left_len > slice.len()` it returns the full slice.
///
/// # Example
/// ```
/// # use devela::Slice;
/// let mut v = [1, 2, 3, 4, 5, 6];
/// assert_eq!(Slice::lsplit_mut(&mut v, 3), &mut [1, 2, 3]);
/// assert_eq!(Slice::lsplit_mut(&mut v, 0), &mut [] as &mut [i32]);
/// assert_eq!(Slice::lsplit_mut(&mut v, 10), &mut [1, 2, 3, 4, 5, 6]);
/// ```
/// See also [`Slice::lsplit_mut`].
pub const fn lsplit_mut(slice: &mut [T], len: usize) -> &mut [T] {
let end_idx = Cmp(len).clamp(0, slice.len());
let (left, _) = slice.split_at_mut(end_idx);
left
}
/* right split */
/// Returns the rightmost sub-`slice` with the given maximum `len`.
///
/// If `left_len > slice.len()` it returns the full slice.
///
/// # Example
/// ```
/// # use devela::Slice;
/// let v = [1, 2, 3, 4, 5, 6];
/// assert_eq!(Slice::rsplit(&v, 3), &[4, 5, 6]);
/// assert_eq!(Slice::rsplit(&v, 0), &[] as &[i32]);
/// assert_eq!(Slice::rsplit(&v, 10), &[1, 2, 3, 4, 5, 6]);
/// ```
#[must_use]
pub const fn rsplit(slice: &[T], len: usize) -> &[T] {
let start_idx = slice.len().saturating_sub(len);
let (_, right) = slice.split_at(start_idx);
right
}
/// Returns the rightmost exclusive sub-`slice` with the given maximum `len`.
///
/// If `left_len > slice.len()` it returns the full slice.
///
/// # Example
/// ```
/// # use devela::Slice;
/// let mut v = [1, 2, 3, 4, 5, 6];
/// assert_eq!(Slice::rsplit_mut(&mut v, 3), &mut [4, 5, 6]);
/// assert_eq!(Slice::rsplit_mut(&mut v, 0), &mut [] as &mut [i32]);
/// assert_eq!(Slice::rsplit_mut(&mut v, 10), &mut [1, 2, 3, 4, 5, 6]);
/// ```
/// See also [`Slice::lsplit_mut`].
#[must_use]
pub const fn rsplit_mut(slice: &mut [T], len: usize) -> &mut [T] {
let start_idx = slice.len().saturating_sub(len);
let (_, right) = slice.split_at_mut(start_idx);
right
}
/* middle split left biased */
/// Returns the middle sub-`slice` with the given maximum `len` and a left bias.
///
/// In case of a non-perfect middle split, it will have one element more on the left.
///
/// If `len > slice.len()` returns the full `slice`.
///
/// # Example
/// ```
/// # use devela::Slice;
/// let v = [1, 2, 3, 4, 5, 6];
/// assert_eq!(Slice::msplit_left(&v, 0), &[] as &[i32]);
/// assert_eq!(Slice::msplit_left(&v, 1), &[3]);
/// assert_eq!(Slice::msplit_left(&v, 2), &[3, 4]);
/// assert_eq!(Slice::msplit_left(&v, 3), &[2, 3, 4]);
/// assert_eq!(Slice::msplit_left(&v, 4), &[2, 3, 4, 5]);
/// assert_eq!(Slice::msplit_left(&v, 5), &[1, 2, 3, 4, 5]);
/// assert_eq!(Slice::msplit_left(&v, 10), &[1, 2, 3, 4, 5, 6]);
/// ```
/// See also [`Slice::msplit_right`].
#[must_use]
pub const fn msplit_left(slice: &[T], len: usize) -> &[T] {
let mid_idx = slice.len() / 2;
let half_len = len / 2;
let start_idx = mid_idx.saturating_sub(half_len + (len % 2));
let end_idx = Cmp(mid_idx + half_len).min(slice.len());
let (_, right) = slice.split_at(start_idx);
let (middle, _) = right.split_at(end_idx - start_idx);
middle
}
/// Returns the middle exclusive sub-`slice` with the given maximum `len` and a
/// left bias.
///
/// In case of a non-perfect middle split, it will have one element more on the left.
///
/// If `len > slice.len()` returns the full `slice`.
///
/// # Example
/// ```
/// # use devela::Slice;
/// let mut v = [1, 2, 3, 4, 5, 6];
/// assert_eq!(Slice::msplit_left_mut(&mut v, 0), &mut [] as &mut [i32]);
/// assert_eq!(Slice::msplit_left_mut(&mut v, 1), &mut [3]);
/// assert_eq!(Slice::msplit_left_mut(&mut v, 2), &mut [3, 4]);
/// assert_eq!(Slice::msplit_left_mut(&mut v, 3), &mut [2, 3, 4]);
/// assert_eq!(Slice::msplit_left_mut(&mut v, 4), &mut [2, 3, 4, 5]);
/// assert_eq!(Slice::msplit_left_mut(&mut v, 5), &mut [1, 2, 3, 4, 5]);
/// assert_eq!(Slice::msplit_left_mut(&mut v, 10), &mut [1, 2, 3, 4, 5, 6]);
/// ```
/// See also [`Slice::msplit_right_mut`].
#[must_use]
pub const fn msplit_left_mut(slice: &mut [T], len: usize) -> &mut [T] {
let mid_idx = slice.len() / 2;
let half_len = len / 2;
let start_idx = mid_idx.saturating_sub(half_len + (len % 2));
let end_idx = Cmp(mid_idx + half_len).min(slice.len());
let (_, right) = slice.split_at_mut(start_idx);
let (middle, _) = right.split_at_mut(end_idx - start_idx);
middle
}
/* middle split right biased */
/// Returns the middle sub-`slice` with the given maximum `len` and a right bias.
///
/// In case of a non-perfect middle split, it will have one element more on the right.
///
/// If `len > slice.len()` returns the full `slice`.
///
/// # Example
/// ```
/// # use devela::Slice;
/// let v = [1, 2, 3, 4, 5, 6];
/// assert_eq!(Slice::msplit_right(&v, 0), &[] as &[i32]);
/// assert_eq!(Slice::msplit_right(&v, 1), &[4]);
/// assert_eq!(Slice::msplit_right(&v, 2), &[3, 4]);
/// assert_eq!(Slice::msplit_right(&v, 3), &[3, 4, 5]);
/// assert_eq!(Slice::msplit_right(&v, 4), &[2, 3, 4, 5]);
/// assert_eq!(Slice::msplit_right(&v, 5), &[2, 3, 4, 5, 6]);
/// assert_eq!(Slice::msplit_right(&v, 10), &[1, 2, 3, 4, 5, 6]);
/// ```
/// See also [`Slice::msplit_left`].
#[must_use]
pub const fn msplit_right(slice: &[T], len: usize) -> &[T] {
let mid_idx = slice.len() / 2;
let half_len = len / 2;
let start_idx = mid_idx.saturating_sub(half_len);
let end_idx = Cmp(mid_idx + half_len + (len % 2)).min(slice.len());
let (_, right) = slice.split_at(start_idx);
let (middle, _) = right.split_at(end_idx - start_idx);
middle
}
/// Returns the middle exclusive sub-`slice` with the given maximum `len` and a
/// right bias.
///
/// In case of a non-perfect middle split, it will have one element more on the right.
///
/// If `len > slice.len()` returns the full `slice`.
/// # Example
/// ```
/// # use devela::Slice;
/// let mut v = [1, 2, 3, 4, 5, 6];
/// assert_eq!(Slice::msplit_right_mut(&mut v, 0), &mut [] as &mut[i32]);
/// assert_eq!(Slice::msplit_right_mut(&mut v, 1), &mut [4]);
/// assert_eq!(Slice::msplit_right_mut(&mut v, 2), &mut [3, 4]);
/// assert_eq!(Slice::msplit_right_mut(&mut v, 3), &mut [3, 4, 5]);
/// assert_eq!(Slice::msplit_right_mut(&mut v, 4), &mut [2, 3, 4, 5]);
/// assert_eq!(Slice::msplit_right_mut(&mut v, 5), &mut [2, 3, 4, 5, 6]);
/// assert_eq!(Slice::msplit_right_mut(&mut v, 10), &mut [1, 2, 3, 4, 5, 6]);
/// ```
/// See also [`Slice::msplit_left_mut`].
#[must_use]
pub const fn msplit_right_mut(slice: &mut [T], len: usize) -> &mut [T] {
let mid_idx = slice.len() / 2;
let half_len = len / 2;
let start_idx = mid_idx.saturating_sub(half_len);
let end_idx = Cmp(mid_idx + half_len + (len % 2)).min(slice.len());
let (_, right) = slice.split_at_mut(start_idx);
let (middle, _) = right.split_at_mut(end_idx - start_idx);
middle
}
}