use core::ops::{Bound, RangeBounds, RangeInclusive};

/// Returns the container key and the index

/// in this container for a given integer.

#[inline]

pub fn split(value: u32) -> (u16, u16) {

    ((value >> 16) as u16, value as u16)

}

Unexecuted instantiation: roaring::bitmap::util::split

Unexecuted instantiation: roaring::bitmap::util::split

/// Returns the original integer from the container

/// key and the index of it in the container.

#[inline]

pub fn join(high: u16, low: u16) -> u32 {

    (u32::from(high) << 16) + u32::from(low)

}

#[derive(Debug, Copy, Clone, PartialEq, Eq)]

pub enum ConvertRangeError {

    Empty,

    StartGreaterThanEnd,

    StartAndEndEqualExcluded,

}

/// Convert a `RangeBounds<u32>` object to `RangeInclusive<u32>`,

pub fn convert_range_to_inclusive<R>(range: R) -> Result<RangeInclusive<u32>, ConvertRangeError>

where

    R: RangeBounds<u32>,

{

    let start_bound = range.start_bound().cloned();

    let end_bound = range.end_bound().cloned();

    match (start_bound, end_bound) {

        (Bound::Excluded(s), Bound::Excluded(e)) if s == e => {

            Err(ConvertRangeError::StartAndEndEqualExcluded)

        }

        (Bound::Included(s) | Bound::Excluded(s), Bound::Included(e) | Bound::Excluded(e))

            if s > e =>

        {

            Err(ConvertRangeError::StartGreaterThanEnd)

        }

        _ => {

            let start = match start_bound {

                Bound::Included(s) => s,

                Bound::Excluded(s) => s.checked_add(1).ok_or(ConvertRangeError::Empty)?,

                Bound::Unbounded => 0,

            };

            let end = match end_bound {

                Bound::Included(e) => e,

                Bound::Excluded(e) => e.checked_sub(1).ok_or(ConvertRangeError::Empty)?,

                Bound::Unbounded => u32::MAX,

            };

            if start > end {

                // This handles e.g. `x..x`: we've ruled out `start > end` overall, so a value must

                // have been changed via exclusion.

                Err(ConvertRangeError::Empty)

            } else {

                Ok(start..=end)

            }

        }

    }

}

#[cfg(test)]

mod test {

    use super::{convert_range_to_inclusive, join, split, ConvertRangeError};

    use core::ops::Bound;

    #[test]

    fn test_split_u32() {

        assert_eq!((0x0000u16, 0x0000u16), split(0x0000_0000u32));

        assert_eq!((0x0000u16, 0x0001u16), split(0x0000_0001u32));

        assert_eq!((0x0000u16, 0xFFFEu16), split(0x0000_FFFEu32));

        assert_eq!((0x0000u16, 0xFFFFu16), split(0x0000_FFFFu32));

        assert_eq!((0x0001u16, 0x0000u16), split(0x0001_0000u32));

        assert_eq!((0x0001u16, 0x0001u16), split(0x0001_0001u32));

        assert_eq!((0xFFFFu16, 0xFFFEu16), split(0xFFFF_FFFEu32));

        assert_eq!((0xFFFFu16, 0xFFFFu16), split(0xFFFF_FFFFu32));

    }

    #[test]

    fn test_join_u32() {

        assert_eq!(0x0000_0000u32, join(0x0000u16, 0x0000u16));

        assert_eq!(0x0000_0001u32, join(0x0000u16, 0x0001u16));

        assert_eq!(0x0000_FFFEu32, join(0x0000u16, 0xFFFEu16));

        assert_eq!(0x0000_FFFFu32, join(0x0000u16, 0xFFFFu16));

        assert_eq!(0x0001_0000u32, join(0x0001u16, 0x0000u16));

        assert_eq!(0x0001_0001u32, join(0x0001u16, 0x0001u16));

        assert_eq!(0xFFFF_FFFEu32, join(0xFFFFu16, 0xFFFEu16));

        assert_eq!(0xFFFF_FFFFu32, join(0xFFFFu16, 0xFFFFu16));

    }

    #[test]

    #[allow(clippy::reversed_empty_ranges)]

    fn test_convert_range_to_inclusive() {

        assert_eq!(Ok(1..=5), convert_range_to_inclusive(1..6));

        assert_eq!(Ok(1..=u32::MAX), convert_range_to_inclusive(1..));

        assert_eq!(Ok(0..=u32::MAX), convert_range_to_inclusive(..));

        assert_eq!(Ok(16..=16), convert_range_to_inclusive(16..=16));

        assert_eq!(

            Ok(11..=19),

            convert_range_to_inclusive((Bound::Excluded(10), Bound::Excluded(20)))

        );

        assert_eq!(Err(ConvertRangeError::Empty), convert_range_to_inclusive(0..0));

        assert_eq!(Err(ConvertRangeError::Empty), convert_range_to_inclusive(5..5));

        assert_eq!(Err(ConvertRangeError::StartGreaterThanEnd), convert_range_to_inclusive(1..0));

        assert_eq!(Err(ConvertRangeError::StartGreaterThanEnd), convert_range_to_inclusive(10..5));

        assert_eq!(

            Err(ConvertRangeError::Empty),

            convert_range_to_inclusive((Bound::Excluded(u32::MAX), Bound::Included(u32::MAX)))

        );

        assert_eq!(

            Err(ConvertRangeError::StartAndEndEqualExcluded),

            convert_range_to_inclusive((Bound::Excluded(u32::MAX), Bound::Excluded(u32::MAX)))

        );

        assert_eq!(

            Err(ConvertRangeError::Empty),

            convert_range_to_inclusive((Bound::Excluded(0), Bound::Included(0)))

        );

    }

}