closed_interval_set/
range_case.rs

//! Sometimes we don't care about whether data comes in normalized or
//! as arbitrary ranges.  This module defines traits and types to help
//! reduce the burden on callers in such cases.
use alloc::vec::Vec;
use smallvec::SmallVec;

use crate::Backing;
use crate::Endpoint;
use crate::RangeVec;

/// Some functions don't care whether their input is normalized; they
/// take `impl Into<RangeCase<...>>`.
///
/// When a function doesn't care about normalisation *and* doesn't want
/// ownership, it can simply accept slices `&[(T, T)]`.
pub struct RangeCase<T: Endpoint> {
    inner: Backing<T>,
    normalized: bool,
}

impl<T: Endpoint> RangeCase<T> {
    /// Creates a [`RangeCase`] from a (not necessarily normalized) vector of ranges.
    ///
    /// This operation takes constant time.
    #[inline(always)]
    pub fn from_vec(inner: Vec<(T, T)>) -> Self {
        Self {
            inner: inner.into(),
            normalized: false,
        }
    }

    /// Creates a [`RangeCase`] from a (not necessarily normalized) smallvec of ranges.
    ///
    /// This operation takes constant time.
    #[inline(always)]
    pub fn from_smallvec<const N: usize>(inner: SmallVec<[(T, T); N]>) -> Self {
        // `INLINE_SIZE == 0` unless inline storage is enabled.
        #[cfg_attr(
            not(feature = "inline_storage"),
            allow(clippy::absurd_extreme_comparisons)
        )]
        let inner: Backing<T> = if inner.len() <= crate::INLINE_SIZE {
            inner.into_iter().collect()
        } else {
            inner.into_vec().into()
        };

        Self {
            inner,
            normalized: false,
        }
    }

    /// Creates a [`RangeCase`] from a (normalized) [`RangeVec`]
    ///
    /// This operation takes constant time.
    #[inline(always)]
    pub fn from_range_vec(set: RangeVec<T>) -> Self {
        Self {
            inner: set.into_inner(),
            normalized: true,
        }
    }

    /// Returns the underlying vector
    ///
    /// This operation takes constant time.
    #[inline(always)]
    pub fn into_inner(self) -> Backing<T> {
        self.inner
    }

    /// Returns a [`RangeVec`] if the underlying vector is known to be
    /// normalized, and a [`Vec`] of ranges otherwise.
    ///
    /// This operation takes constant time.
    #[inline(always)]
    pub fn unerase(self) -> Result<RangeVec<T>, Backing<T>> {
        if self.normalized {
            Ok(unsafe { RangeVec::new_unchecked(self.inner) })
        } else {
            Err(self.inner)
        }
    }
}

impl<T: Endpoint> From<RangeVec<T>> for RangeCase<T> {
    #[inline(always)]
    fn from(item: RangeVec<T>) -> RangeCase<T> {
        RangeCase::from_range_vec(item)
    }
}

impl<T: Endpoint> From<Vec<(T, T)>> for RangeCase<T> {
    #[inline(always)]
    fn from(item: Vec<(T, T)>) -> RangeCase<T> {
        RangeCase::from_vec(item)
    }
}

impl<T: Endpoint, const N: usize> From<SmallVec<[(T, T); N]>> for RangeCase<T> {
    #[inline(always)]
    fn from(item: SmallVec<[(T, T); N]>) -> RangeCase<T> {
        RangeCase::from_smallvec(item)
    }
}

#[cfg_attr(coverage_nightly, coverage(off))]
#[test]
fn test_smoke() {
    use alloc::vec;
    use smallvec::smallvec;

    let x: RangeCase<_> = vec![(1u8, 2u8)].into();
    assert_eq!(x.into_inner().into_vec(), vec![(1u8, 2u8)]);

    let smallvec: Backing<u8> = smallvec![(1u8, 2u8)];
    let x: RangeCase<_> = smallvec.into();
    assert_eq!(x.unerase().unwrap_err().into_vec(), vec![(1u8, 2u8)]);

    let smallervec: SmallVec<[(u8, u8); 0]> = smallvec![(1u8, 2u8)];
    let x: RangeCase<_> = smallervec.into();
    assert_eq!(x.unerase().unwrap_err().into_vec(), vec![(1u8, 2u8)]);

    let largervec: SmallVec<[(u8, u8); crate::INLINE_SIZE + 1]> = smallvec![(1u8, 2u8)];
    let x: RangeCase<_> = largervec.into();
    assert_eq!(x.unerase().unwrap_err().into_vec(), vec![(1u8, 2u8)]);

    let vec = unsafe { RangeVec::new_unchecked(smallvec![(1u8, 2u8)]) };
    let x: RangeCase<_> = vec.clone().into();
    assert_eq!(x.unerase().unwrap(), vec);
}
closed_interval_set/range_case.rs

closed_interval_set/
range_case.rs
