bool -> Primitive casts (#8621)

Support of bool -> Primitive casts.
This is a subtask for pushing expressions of form
"WHERE prefix(...) > 0" to Duckdb.

Signed-off-by: Mikhail Kot <mikhail@spiraldb.com>

Author: myrrc

vortex-array/src/arrays/bool/compute/cast.rs

@@ -1,6 +1,9 @@
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-FileCopyrightText: Copyright the Vortex contributors
 
+use num_traits::One;
+use num_traits::Zero;
+use vortex_buffer::BufferMut;
 use vortex_error::VortexResult;
 
 use crate::ArrayRef;
@@ -9,8 +12,10 @@ use crate::IntoArray;
 use crate::array::ArrayView;
 use crate::arrays::Bool;
 use crate::arrays::BoolArray;
+use crate::arrays::PrimitiveArray;
 use crate::arrays::bool::BoolArrayExt;
 use crate::dtype::DType;
+use crate::match_each_native_ptype;
 use crate::scalar_fn::fns::cast::CastKernel;
 use crate::scalar_fn::fns::cast::CastReduce;
 
@@ -38,17 +43,34 @@ impl CastKernel for Bool {
         dtype: &DType,
         ctx: &mut ExecutionCtx,
     ) -> VortexResult<Option<ArrayRef>> {
-        if !dtype.is_boolean() {
-            return Ok(None);
+        if dtype.is_boolean() {
+            let new_validity =
+                array
+                    .validity()?
+                    .cast_nullability(dtype.nullability(), array.len(), ctx)?;
+            return Ok(Some(
+                BoolArray::new(array.to_bit_buffer(), new_validity).into_array(),
+            ));
         }
 
+        let DType::Primitive(new_ptype, new_nullability) = dtype else {
+            return Ok(None);
+        };
+
         let new_validity =
             array
                 .validity()?
-                .cast_nullability(dtype.nullability(), array.len(), ctx)?;
-        Ok(Some(
-            BoolArray::new(array.to_bit_buffer(), new_validity).into_array(),
-        ))
+                .cast_nullability(*new_nullability, array.len(), ctx)?;
+
+        let bits = array.to_bit_buffer();
+        let len = bits.len();
+
+        Ok(Some(match_each_native_ptype!(*new_ptype, |T| {
+            let (one, zero) = (<T as One>::one(), <T as Zero>::zero());
+            let mut buffer = BufferMut::<T>::with_capacity(len);
+            buffer.extend(bits.iter().map(|v| if v { one } else { zero }));
+            PrimitiveArray::new(buffer.freeze(), new_validity).into_array()
+        })))
     }
 }
 
@@ -67,6 +89,7 @@ mod tests {
     use crate::compute::conformance::cast::test_cast_conformance;
     use crate::dtype::DType;
     use crate::dtype::Nullability;
+    use crate::dtype::PType;
 
     static SESSION: LazyLock<VortexSession> = LazyLock::new(crate::array_session);
 
@@ -102,4 +125,22 @@ mod tests {
     fn test_cast_bool_conformance(#[case] array: BoolArray) {
         test_cast_conformance(&array.into_array());
     }
+
+    #[rstest]
+    #[case(PType::I8)]
+    #[case(PType::I32)]
+    #[case(PType::I64)]
+    #[case(PType::U8)]
+    #[case(PType::U64)]
+    #[case(PType::F32)]
+    #[case(PType::F64)]
+    fn cast_bool_to_primitive(#[case] target: PType) {
+        let mut ctx = SESSION.create_execution_ctx();
+        let arr = BoolArray::from_iter(vec![true, false, true]).into_array();
+        let out = arr
+            .cast(DType::Primitive(target, Nullability::NonNullable))
+            .unwrap();
+        let out = out.execute::<Canonical>(&mut ctx).unwrap().into_array();
+        assert_eq!(out.len(), 3);
+    }
 }