granges 0.2.2

A Rust library and command line tool for genomic range operations.
Documentation 
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//! Range operations.
//!
use crate::{traits::AdjustableGenericRange, Position, PositionOffset};

/// Adjusts the start and end coordinates of a range, ensuring the adjusted range is
/// within [0, length] and returning `None` if the range has zero width after adjustment.
pub fn adjust_range<R: AdjustableGenericRange>(
    mut range: R,
    start_delta: PositionOffset,
    end_delta: PositionOffset,
    length: Position,
) -> Option<R> {
    let start: PositionOffset = range.start().try_into().unwrap();
    let end: PositionOffset = range.end().try_into().unwrap();
    let length: PositionOffset = length.try_into().unwrap();

    // ensure within [0, length]
    let new_start = (start + start_delta).max(0).min(length);
    // ensure new_end >= new_start and within [0, length]
    let new_end = (end + end_delta).max(new_start).min(length);

    // check for zero-width range
    if new_end <= new_start {
        // return None if the range has zero width
        None
    } else {
        range.set_start(new_start.try_into().unwrap());
        range.set_end(new_end.try_into().unwrap());
        Some(range)
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::ranges::RangeIndexed;

    #[test]
    fn test_normal_adjustment() {
        let range = RangeIndexed::new(5, 10, 1);
        let adjusted = adjust_range(range, -2, 3, 15).unwrap();
        assert_eq!(adjusted, RangeIndexed::new(3, 13, 1));
    }

    #[test]
    fn test_out_of_bounds_adjustment() {
        let range = RangeIndexed::new(10, 12, 2);
        let adjusted = adjust_range(range, -5, 20, 15).unwrap();
        assert_eq!(adjusted, RangeIndexed::new(5, 15, 2));
    }

    #[test]
    fn test_zero_width_result() {
        let range = RangeIndexed::new(5, 10, 3);
        assert!(adjust_range(range, 5, -5, 15).is_none());
    }
}