polars_buffer/
lib.rs

1pub mod buffer;
2pub mod storage;
3
4use std::ops;
5
6pub use buffer::Buffer;
7pub use storage::SharedStorage;
8
9// Copied from the stdlib.
10fn slice_index_fail(start: usize, end: usize, len: usize) -> ! {
11    if start > len {
12        panic!("range start index {start} out of range for slice of length {len}",)
13    }
14
15    if end > len {
16        panic!("range end index {end} out of range for slice of length {len}",)
17    }
18
19    if start > end {
20        panic!("slice index starts at {start} but ends at {end}",)
21    }
22
23    // Only reachable if the range was a `RangeInclusive` or a
24    // `RangeToInclusive`, with `end == len`.
25    panic!("range end index {end} out of range for slice of length {len}",)
26}
27
28#[must_use]
29pub fn check_range<R>(range: R, bounds: ops::RangeTo<usize>) -> ops::Range<usize>
30where
31    R: ops::RangeBounds<usize>,
32{
33    let len = bounds.end;
34    let end = match range.end_bound() {
35        ops::Bound::Included(&end) if end >= len => slice_index_fail(0, end, len),
36        // Cannot overflow because `end < len` implies `end < usize::MAX`.
37        ops::Bound::Included(&end) => end + 1,
38
39        ops::Bound::Excluded(&end) if end > len => slice_index_fail(0, end, len),
40        ops::Bound::Excluded(&end) => end,
41        ops::Bound::Unbounded => len,
42    };
43
44    let start = match range.start_bound() {
45        ops::Bound::Excluded(&start) if start >= end => slice_index_fail(start, end, len),
46        // Cannot overflow because `start < end` implies `start < usize::MAX`.
47        ops::Bound::Excluded(&start) => start + 1,
48
49        ops::Bound::Included(&start) if start > end => slice_index_fail(start, end, len),
50        ops::Bound::Included(&start) => start,
51
52        ops::Bound::Unbounded => 0,
53    };
54
55    ops::Range { start, end }
56}
57
58#[must_use]
59pub fn decode_range_unchecked<R>(range: R, bounds: ops::RangeTo<usize>) -> ops::Range<usize>
60where
61    R: ops::RangeBounds<usize>,
62{
63    let len = bounds.end;
64    let end = match range.end_bound() {
65        ops::Bound::Included(&end) => end + 1,
66        ops::Bound::Excluded(&end) => end,
67        ops::Bound::Unbounded => len,
68    };
69
70    let start = match range.start_bound() {
71        ops::Bound::Excluded(&start) => start + 1,
72        ops::Bound::Included(&start) => start,
73        ops::Bound::Unbounded => 0,
74    };
75
76    ops::Range { start, end }
77}
polars_buffer/lib.rs

polars_buffer/
lib.rs
