vortex-zigzag 0.69.0

Vortex zig zag array
Documentation 
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// SPDX-License-Identifier: Apache-2.0
// SPDX-FileCopyrightText: Copyright the Vortex contributors

use vortex_array::ArrayRef;
use vortex_array::ArrayView;
use vortex_array::IntoArray;
use vortex_array::builtins::ArrayBuiltins;
use vortex_array::dtype::DType;
use vortex_array::scalar_fn::fns::cast::CastReduce;
use vortex_error::VortexResult;

use crate::ZigZag;
use crate::array::ZigZagArrayExt;
impl CastReduce for ZigZag {
    fn cast(array: ArrayView<'_, Self>, dtype: &DType) -> VortexResult<Option<ArrayRef>> {
        if !dtype.is_signed_int() {
            return Ok(None);
        }

        let new_encoded_dtype =
            DType::Primitive(dtype.as_ptype().to_unsigned(), dtype.nullability());
        let new_encoded = array.encoded().cast(new_encoded_dtype)?;
        Ok(Some(ZigZag::try_new(new_encoded)?.into_array()))
    }
}

#[cfg(test)]
mod tests {
    use rstest::rstest;
    use vortex_array::IntoArray;
    use vortex_array::arrays::PrimitiveArray;
    use vortex_array::assert_arrays_eq;
    use vortex_array::builtins::ArrayBuiltins;
    use vortex_array::compute::conformance::cast::test_cast_conformance;
    use vortex_array::dtype::DType;
    use vortex_array::dtype::Nullability;
    use vortex_array::dtype::PType;

    use crate::ZigZagArray;
    use crate::zigzag_encode;

    #[test]
    fn test_cast_zigzag_i32_to_i64() {
        let values = PrimitiveArray::from_iter([-100i32, -1, 0, 1, 100]);
        let zigzag = zigzag_encode(values.as_view()).unwrap();

        let casted = zigzag
            .into_array()
            .cast(DType::Primitive(PType::I64, Nullability::NonNullable))
            .unwrap();
        assert_eq!(
            casted.dtype(),
            &DType::Primitive(PType::I64, Nullability::NonNullable)
        );

        // Verify the result is still a ZigZagArray (not decoded)
        // Note: The result might be wrapped, so let's check the encoding ID
        assert_eq!(
            casted.encoding_id().as_ref(),
            "vortex.zigzag",
            "Cast should preserve ZigZag encoding"
        );

        assert_arrays_eq!(casted, PrimitiveArray::from_iter([-100i64, -1, 0, 1, 100]));
    }

    #[test]
    fn test_cast_zigzag_width_changes() {
        // Test i32 to i16 (narrowing)
        let values = PrimitiveArray::from_iter([100i32, -50, 0, 25, -100]);
        let zigzag = zigzag_encode(values.as_view()).unwrap();

        let casted = zigzag
            .into_array()
            .cast(DType::Primitive(PType::I16, Nullability::NonNullable))
            .unwrap();
        assert_eq!(
            casted.encoding_id().as_ref(),
            "vortex.zigzag",
            "Should remain ZigZag encoded"
        );

        assert_arrays_eq!(
            casted,
            PrimitiveArray::from_iter([100i16, -50, 0, 25, -100])
        );

        // Test i16 to i64 (widening)
        let values16 = PrimitiveArray::from_iter([1000i16, -500, 0, 250, -1000]);
        let zigzag16 = zigzag_encode(values16.as_view()).unwrap();

        let casted64 = zigzag16
            .into_array()
            .cast(DType::Primitive(PType::I64, Nullability::NonNullable))
            .unwrap();
        assert_eq!(
            casted64.encoding_id().as_ref(),
            "vortex.zigzag",
            "Should remain ZigZag encoded"
        );

        assert_arrays_eq!(
            casted64,
            PrimitiveArray::from_iter([1000i64, -500, 0, 250, -1000])
        );
    }

    #[test]
    fn test_cast_zigzag_nullable() {
        let values =
            PrimitiveArray::from_option_iter([Some(-10i32), None, Some(0), Some(10), None]);
        let zigzag = zigzag_encode(values.as_view()).unwrap();

        let casted = zigzag
            .into_array()
            .cast(DType::Primitive(PType::I64, Nullability::Nullable))
            .unwrap();
        assert_eq!(
            casted.dtype(),
            &DType::Primitive(PType::I64, Nullability::Nullable)
        );
    }

    #[rstest]
    #[case(zigzag_encode(PrimitiveArray::from_iter([-100i32, -50, -1, 0, 1, 50, 100]).as_view()).unwrap())]
    #[case(zigzag_encode(PrimitiveArray::from_iter([-1000i64, -1, 0, 1, 1000]).as_view()).unwrap())]
    #[case(zigzag_encode(PrimitiveArray::from_option_iter([Some(-5i16), None, Some(0), Some(5), None]).as_view()).unwrap())]
    #[case(zigzag_encode(PrimitiveArray::from_iter([i32::MIN, -1, 0, 1, i32::MAX]).as_view()).unwrap())]
    fn test_cast_zigzag_conformance(#[case] array: ZigZagArray) {
        test_cast_conformance(&array.into_array());
    }
}