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use crate::{Growth, SplitVec};
use orx_pinned_vec::PinnedVec;
use std::ops::RangeBounds;
#[derive(PartialEq, Eq, Debug, Clone)]
/// Returns the result of trying to get a slice as a contagious memory from the split vector.
pub enum SplitVecSlice<'a, T> {
/// The desired range completely belongs to one fragment and the slice can be provided.
Ok(&'a [T]),
/// The desired range is split to at least two fragments.
/// The tuple contains indices of the fragments containing
/// the first and last element of the desired range.
Fragmented(usize, usize),
/// An error case where the desired range is out of bounds of the vector.
OutOfBounds,
}
impl<T, G: Growth> SplitVec<T, G> {
fn range_start<R: RangeBounds<usize>>(range: &R) -> usize {
match range.start_bound() {
std::ops::Bound::Excluded(x) => x + 1,
std::ops::Bound::Included(x) => *x,
std::ops::Bound::Unbounded => 0,
}
}
fn range_end<R: RangeBounds<usize>>(&self, range: &R) -> usize {
match range.end_bound() {
std::ops::Bound::Excluded(x) => *x,
std::ops::Bound::Included(x) => x + 1,
std::ops::Bound::Unbounded => self.len(),
}
}
/// Returns the result of trying to return the required `range` as a contagious slice of data.
/// It might return Ok of the slice if the range belongs to one fragment.
///
/// Otherwise, one of the two failure cases will be returned:
/// * OutOfBounds if the range does not fit in the range of the entire split vector, or
/// * Fragmented if the range belongs to at least two fragments, additionally returns the fragment indices of the range.
///
/// # Examples
///
/// ```
/// use orx_split_vec::*;
///
/// let mut vec = SplitVec::with_linear_growth(2);
///
/// vec.extend_from_slice(&[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
///
/// assert_eq!(4, vec.fragments()[0].capacity());
/// assert_eq!(4, vec.fragments()[1].capacity());
/// assert_eq!(4, vec.fragments()[2].capacity());
///
/// assert_eq!(4, vec.fragments()[0].len()); // [0, 1, 2, 3]
/// assert_eq!(4, vec.fragments()[1].len()); // [4, 5, 6, 7]
/// assert_eq!(2, vec.fragments()[2].len()); // [8, 9]
///
/// // Ok
/// assert_eq!(SplitVecSlice::Ok(&[0, 1, 2, 3]), vec.try_get_slice(0..4));
/// assert_eq!(SplitVecSlice::Ok(&[5, 6]), vec.try_get_slice(5..7));
/// assert_eq!(SplitVecSlice::Ok(&[8, 9]), vec.try_get_slice(8..10));
///
/// // Fragmented
/// assert_eq!(SplitVecSlice::Fragmented(0, 1), vec.try_get_slice(3..6));
/// assert_eq!(SplitVecSlice::Fragmented(0, 2), vec.try_get_slice(3..9));
/// assert_eq!(SplitVecSlice::Fragmented(1, 2), vec.try_get_slice(7..9));
///
/// // OutOfBounds
/// assert_eq!(SplitVecSlice::OutOfBounds, vec.try_get_slice(5..12));
/// assert_eq!(SplitVecSlice::OutOfBounds, vec.try_get_slice(10..11));
/// ```
pub fn try_get_slice<R: RangeBounds<usize>>(&self, range: R) -> SplitVecSlice<T> {
let a = Self::range_start(&range);
let b = self.range_end(&range);
if b == 0 {
SplitVecSlice::Ok(&[])
} else if let Some((sf, si)) = self.get_fragment_and_inner_indices(a) {
if let Some((ef, ei)) = self.get_fragment_and_inner_indices(b - 1) {
if sf == ef {
SplitVecSlice::Ok(&self.fragments[sf][si..=ei])
} else {
SplitVecSlice::Fragmented(sf, ef)
}
} else {
SplitVecSlice::OutOfBounds
}
} else {
SplitVecSlice::OutOfBounds
}
}
/// Returns the view on the required `range` as a vector of slices:
///
/// * returns an empty vector if the range is out of bounds;
/// * returns a vector with one slice if the range completely belongs to one fragment (in this case `try_get_slice` would return Ok),
/// * returns an ordered vector of slices when chained forms the required range.
///
/// # Examples
///
/// ```
/// use orx_split_vec::*;
///
/// let mut vec = SplitVec::with_linear_growth(2);
///
/// vec.extend_from_slice(&[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
///
/// assert_eq!(4, vec.fragments()[0].capacity());
/// assert_eq!(4, vec.fragments()[1].capacity());
/// assert_eq!(4, vec.fragments()[2].capacity());
///
/// assert_eq!(4, vec.fragments()[0].len()); // [0, 1, 2, 3]
/// assert_eq!(4, vec.fragments()[1].len()); // [4, 5, 6, 7]
/// assert_eq!(2, vec.fragments()[2].len()); // [8, 9]
///
/// // single fragment
/// assert_eq!(vec![&[0, 1, 2, 3]], vec.slice(0..4));
/// assert_eq!(vec![&[5, 6]], vec.slice(5..7));
/// assert_eq!(vec![&[8, 9]], vec.slice(8..10));
///
/// // Fragmented
/// assert_eq!(vec![&vec![3], &vec![4, 5]], vec.slice(3..6));
/// assert_eq!(vec![&vec![3], &vec![4, 5, 6, 7], &vec![8]], vec.slice(3..9));
/// assert_eq!(vec![&vec![7], &vec![8]], vec.slice(7..9));
///
/// // OutOfBounds
/// assert!(vec.slice(5..12).is_empty());
/// assert!(vec.slice(10..11).is_empty());
/// ```
pub fn slice<R: RangeBounds<usize>>(&self, range: R) -> Vec<&[T]> {
let a = Self::range_start(&range);
let b = self.range_end(&range);
if b == 0 {
vec![]
} else if let Some((sf, si)) = self.get_fragment_and_inner_indices(a) {
if let Some((ef, ei)) = self.get_fragment_and_inner_indices(b - 1) {
if sf == ef {
vec![&self.fragments[sf][si..=ei]]
} else {
let mut vec = Vec::with_capacity(ef - sf + 1);
vec.push(&self.fragments[sf][si..]);
for f in sf + 1..ef {
vec.push(&self.fragments[f]);
}
vec.push(&self.fragments[ef][..=ei]);
vec
}
} else {
vec![]
}
} else {
vec![]
}
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::test_all_growth_types;
use crate::*;
#[test]
fn range_start_end() {
fn test<G: Growth>(vec: SplitVec<usize, G>) {
type S<G> = SplitVec<usize, G>;
assert_eq!(10, S::<G>::range_start(&(10..20)));
assert_eq!(10, S::<G>::range_start(&(10..=20)));
assert_eq!(0, S::<G>::range_start(&(..20)));
assert_eq!(10, S::<G>::range_start(&(10..)));
assert_eq!(0, S::<G>::range_start(&(..)));
assert_eq!(20, vec.range_end(&(10..20)));
assert_eq!(21, vec.range_end(&(10..=20)));
assert_eq!(20, vec.range_end(&(..20)));
assert_eq!(vec.len(), vec.range_end(&(10..)));
assert_eq!(vec.len(), vec.range_end(&(..)));
}
test_all_growth_types!(test);
}
#[test]
fn try_get_slice() {
fn test<G: Growth>(mut vec: SplitVec<usize, G>) {
for i in 0..42 {
assert_eq!(SplitVecSlice::OutOfBounds, vec.try_get_slice(0..(i + 1)));
assert_eq!(SplitVecSlice::OutOfBounds, vec.try_get_slice(i..(i + 1)));
vec.push(i);
}
for f in 0..vec.fragments.len() {
let begin: usize = vec.fragments.iter().take(f).map(|f| f.len()).sum();
let end = begin + vec.fragments[f].len();
let half = begin + vec.fragments[f].len() / 2;
// ok
let slice_full_fragment = vec.try_get_slice(begin..end);
assert_eq!(slice_full_fragment, SplitVecSlice::Ok(&vec.fragments[f]));
let slice_half_fragment = vec.try_get_slice(begin..half);
assert_eq!(
slice_half_fragment,
SplitVecSlice::Ok(&vec.fragments[f][0..vec.fragments[f].len() / 2])
);
let slice_half_fragment = vec.try_get_slice(half..end);
assert_eq!(
slice_half_fragment,
SplitVecSlice::Ok(
&vec.fragments[f][vec.fragments[f].len() / 2..vec.fragments[f].len()]
)
);
// fragmented
if f > 0 {
let prev_begin = begin - 1;
let slice = vec.try_get_slice(prev_begin..end);
assert_eq!(slice, SplitVecSlice::Fragmented(f - 1, f));
if f < vec.fragments.len() - 1 {
let next_end = end + 1;
let slice = vec.try_get_slice(begin..next_end);
assert_eq!(slice, SplitVecSlice::Fragmented(f, f + 1));
let slice = vec.try_get_slice(prev_begin..next_end);
assert_eq!(slice, SplitVecSlice::Fragmented(f - 1, f + 1));
}
}
}
}
test_all_growth_types!(test);
}
#[test]
fn slice() {
fn test<G: Growth>(mut vec: SplitVec<usize, G>) {
for i in 0..184 {
assert!(vec.slice(i..i + 1).is_empty());
assert!(vec.slice(0..i + 1).is_empty());
vec.push(i);
}
let slice = vec.slice(0..vec.len());
let mut combined = vec![];
for s in slice {
combined.extend_from_slice(s);
}
for i in 0..184 {
assert_eq!(i, vec[i]);
assert_eq!(i, combined[i]);
}
let begin = vec.len() / 4;
let end = 3 * vec.len() / 4;
let slice = vec.slice(begin..end);
let mut combined = vec![];
for s in slice {
combined.extend_from_slice(s);
}
for i in begin..end {
assert_eq!(i, vec[i]);
assert_eq!(i, combined[i - begin]);
}
}
test_all_growth_types!(test);
}
}