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use crate::ChunkedVec;
impl<T, const N: usize> ChunkedVec<T, N> {
/// Returns the fixed chunk size used by this vector.
///
/// # Examples
/// ```
/// use chunked_vec::{ChunkedVec, ChunkedVecSized};
///
/// let vec: ChunkedVec<i32, 128> = ChunkedVecSized::new();
/// assert_eq!(vec.chunk_size(), 128);
/// ```
#[inline]
#[must_use]
pub const fn chunk_size(&self) -> usize {
N
}
/// Returns the number of logical chunks currently containing elements.
///
/// This count is derived from the vector length, so retained but unused
/// chunks after [`truncate`](ChunkedVec::truncate) or
/// [`clear`](ChunkedVec::clear) are not included.
///
/// # Examples
/// ```
/// use chunked_vec::{ChunkedVec, ChunkedVecSized};
///
/// let mut vec: ChunkedVec<i32, 4> = ChunkedVecSized::new();
/// vec.extend(0..9);
/// assert_eq!(vec.chunk_count(), 3);
///
/// vec.truncate(4);
/// assert_eq!(vec.chunk_count(), 1);
/// ```
#[inline]
#[must_use]
pub fn chunk_count(&self) -> usize {
Self::chunk_count_for_len(self.len)
}
/// Returns the elements stored in the chunk at `chunk_index`.
///
/// The last chunk may contain fewer than `N` elements.
///
/// # Examples
/// ```
/// use chunked_vec::{ChunkedVec, ChunkedVecSized};
///
/// let mut vec: ChunkedVec<i32, 4> = ChunkedVecSized::new();
/// vec.extend(0..6);
///
/// assert_eq!(vec.chunk(0), Some(&[0, 1, 2, 3][..]));
/// assert_eq!(vec.chunk(1), Some(&[4, 5][..]));
/// assert_eq!(vec.chunk(2), None);
/// ```
#[must_use]
pub fn chunk(&self, chunk_index: usize) -> Option<&[T]> {
let len = self.chunk_len(chunk_index)?;
let ptr = self.data[chunk_index].as_ptr().cast::<T>();
unsafe { Some(std::slice::from_raw_parts(ptr, len)) }
}
/// Returns a mutable slice over the elements stored in the chunk at
/// `chunk_index`.
///
/// The last chunk may contain fewer than `N` elements.
///
/// # Examples
/// ```
/// use chunked_vec::{ChunkedVec, ChunkedVecSized};
///
/// let mut vec: ChunkedVec<i32, 4> = ChunkedVecSized::new();
/// vec.extend(0..6);
///
/// if let Some(chunk) = vec.chunk_mut(1) {
/// chunk[0] = 40;
/// chunk[1] = 50;
/// }
///
/// assert_eq!(vec[4], 40);
/// assert_eq!(vec[5], 50);
/// ```
pub fn chunk_mut(&mut self, chunk_index: usize) -> Option<&mut [T]> {
let len = self.chunk_len(chunk_index)?;
let ptr = self.data[chunk_index].as_mut_ptr().cast::<T>();
unsafe { Some(std::slice::from_raw_parts_mut(ptr, len)) }
}
/// Returns the first logical chunk in the vector.
///
/// # Examples
/// ```
/// use chunked_vec::{ChunkedVec, ChunkedVecSized};
///
/// let mut vec: ChunkedVec<i32, 4> = ChunkedVecSized::new();
/// assert_eq!(vec.first_chunk(), None);
///
/// vec.extend(0..6);
/// assert_eq!(vec.first_chunk(), Some(&[0, 1, 2, 3][..]));
/// ```
#[must_use]
pub fn first_chunk(&self) -> Option<&[T]> {
self.chunk(0)
}
/// Returns the first logical chunk in the vector as a mutable slice.
///
/// # Examples
/// ```
/// use chunked_vec::{ChunkedVec, ChunkedVecSized};
///
/// let mut vec: ChunkedVec<i32, 4> = ChunkedVecSized::new();
/// vec.extend(0..6);
///
/// if let Some(chunk) = vec.first_chunk_mut() {
/// chunk[0] = 10;
/// chunk[1] = 11;
/// }
///
/// assert_eq!(vec.first_chunk(), Some(&[10, 11, 2, 3][..]));
/// ```
pub fn first_chunk_mut(&mut self) -> Option<&mut [T]> {
self.chunk_mut(0)
}
/// Returns the last logical chunk in the vector.
///
/// # Examples
/// ```
/// use chunked_vec::{ChunkedVec, ChunkedVecSized};
///
/// let mut vec: ChunkedVec<i32, 4> = ChunkedVecSized::new();
/// assert_eq!(vec.last_chunk(), None);
///
/// vec.extend(0..6);
/// assert_eq!(vec.last_chunk(), Some(&[4, 5][..]));
/// ```
#[must_use]
pub fn last_chunk(&self) -> Option<&[T]> {
self.chunk(self.chunk_count().checked_sub(1)?)
}
/// Returns the last logical chunk in the vector as a mutable slice.
///
/// # Examples
/// ```
/// use chunked_vec::{ChunkedVec, ChunkedVecSized};
///
/// let mut vec: ChunkedVec<i32, 4> = ChunkedVecSized::new();
/// vec.extend(0..6);
///
/// if let Some(chunk) = vec.last_chunk_mut() {
/// chunk[0] = 10;
/// chunk[1] = 11;
/// }
///
/// assert_eq!(vec.last_chunk(), Some(&[10, 11][..]));
/// ```
pub fn last_chunk_mut(&mut self) -> Option<&mut [T]> {
let last_chunk_index = self.chunk_count().checked_sub(1)?;
self.chunk_mut(last_chunk_index)
}
#[inline]
#[must_use]
pub(crate) fn chunk_len(&self, chunk_index: usize) -> Option<usize> {
let chunk_count = self.chunk_count();
if chunk_index >= chunk_count {
return None;
}
let start = chunk_index * N;
Some((self.len - start).min(N))
}
}
#[cfg(test)]
mod tests {
use crate::{ChunkedVec, ChunkedVecSized};
#[test]
fn test_chunk_count_tracks_logical_chunks() {
let mut vec: ChunkedVec<i32, 4> = ChunkedVecSized::new();
assert_eq!(vec.chunk_size(), 4);
assert_eq!(vec.chunk_count(), 0);
vec.extend(0..9);
assert_eq!(vec.chunk_count(), 3);
vec.truncate(4);
assert_eq!(vec.chunk_count(), 1);
assert_eq!(vec.allocated_capacity(), 12);
}
#[test]
fn test_chunk_access() {
let mut vec: ChunkedVec<i32, 4> = ChunkedVecSized::new();
vec.extend(0..10);
assert_eq!(vec.chunk(0), Some(&[0, 1, 2, 3][..]));
assert_eq!(vec.chunk(1), Some(&[4, 5, 6, 7][..]));
assert_eq!(vec.chunk(2), Some(&[8, 9][..]));
assert_eq!(vec.chunk(3), None);
}
#[test]
fn test_chunk_mut_access() {
let mut vec: ChunkedVec<i32, 4> = ChunkedVecSized::new();
vec.extend(0..6);
let chunk = vec.chunk_mut(1).unwrap();
chunk[0] = 40;
chunk[1] = 50;
assert_eq!(vec.chunk(1), Some(&[40, 50][..]));
assert_eq!(vec.chunk_mut(2), None);
}
#[test]
fn test_last_chunk_access() {
let mut vec: ChunkedVec<i32, 4> = ChunkedVecSized::new();
assert_eq!(vec.last_chunk(), None);
assert_eq!(vec.last_chunk_mut(), None);
vec.extend(0..6);
assert_eq!(vec.last_chunk(), Some(&[4, 5][..]));
let last_chunk = vec.last_chunk_mut().unwrap();
last_chunk[0] = 10;
last_chunk[1] = 11;
assert_eq!(vec.last_chunk(), Some(&[10, 11][..]));
}
#[test]
fn test_first_chunk_access() {
let mut vec: ChunkedVec<i32, 4> = ChunkedVecSized::new();
assert_eq!(vec.first_chunk(), None);
assert_eq!(vec.first_chunk_mut(), None);
vec.extend(0..6);
assert_eq!(vec.first_chunk(), Some(&[0, 1, 2, 3][..]));
let first_chunk = vec.first_chunk_mut().unwrap();
first_chunk[0] = 10;
first_chunk[1] = 11;
assert_eq!(vec.first_chunk(), Some(&[10, 11, 2, 3][..]));
}
}