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use vortex_error::{vortex_bail, vortex_err, VortexResult};

use crate::Array;

/// Limit array to start...stop range
pub trait SliceFn {
    fn slice(&self, start: usize, stop: usize) -> VortexResult<Array>;
}

/// Return a zero-copy slice of an array, between `start` (inclusive) and `end` (exclusive).
///
/// # Panics
///
/// Slicing will panic if you attempt to slice a range that exceeds the bounds of the
/// underlying array.
///
/// # Errors
///
/// Slicing returns an error if the underlying codec's [slice](SliceFn::slice()) implementation
/// returns an error.
pub fn slice(array: &Array, start: usize, stop: usize) -> VortexResult<Array> {
    check_slice_bounds(array, start, stop)?;

    array.with_dyn(|c| {
        c.slice().map(|t| t.slice(start, stop)).unwrap_or_else(|| {
            Err(vortex_err!(
                NotImplemented: "slice",
                array.encoding().id()
            ))
        })
    })
}

fn check_slice_bounds(array: &Array, start: usize, stop: usize) -> VortexResult<()> {
    if start > array.len() {
        vortex_bail!(OutOfBounds: start, 0, array.len());
    }
    if stop > array.len() {
        vortex_bail!(OutOfBounds: stop, 0, array.len());
    }
    Ok(())
}