feat(rust/sedona-functions): Implement native ST_ZMFlag using WKBHeader (#260)

Author: petern48

benchmarks/test_functions.py

@@ -293,3 +293,21 @@ def queries():
             eng.execute_and_collect(f"SELECT ST_EndPoint(geom1) from {table}")
 
         benchmark(queries)
+
+    @pytest.mark.parametrize(
+        "eng", [SedonaDBSingleThread, PostGISSingleThread, DuckDBSingleThread]
+    )
+    @pytest.mark.parametrize(
+        "table",
+        [
+            "collections_simple",
+            "collections_complex",
+        ],
+    )
+    def test_st_zmflag(self, benchmark, eng, table):
+        eng = self._get_eng(eng)
+
+        def queries():
+            eng.execute_and_collect(f"SELECT ST_ZmFlag(geom1) from {table}")
+
+        benchmark(queries)

python/sedonadb/tests/functions/test_functions.py

@@ -1694,3 +1694,33 @@ def test_st_simplifypreservetopology(eng, geom, tolerance, expected):
         f"SELECT ST_SimplifyPreserveTopology({geom_or_null(geom)}, {val_or_null(tolerance)})",
         expected,
     )
+
+
+@pytest.mark.parametrize("eng", [SedonaDB, PostGIS])
+@pytest.mark.parametrize(
+    ("geom", "expected"),
+    [
+        (None, None),
+        ("POINT EMPTY", 0),
+        ("POINT Z EMPTY", 2),
+        ("POINT M EMPTY", 1),
+        ("POINT ZM EMPTY", 3),
+        ("POINT Z (0 0 0)", 2),
+        ("POINT M (0 0 0)", 1),
+        ("POINT ZM (0 0 0 0)", 3),
+        ("LINESTRING EMPTY", 0),
+        ("LINESTRING Z EMPTY", 2),
+        ("LINESTRING Z (0 0 0, 1 1 1)", 2),
+        ("POLYGON EMPTY", 0),
+        ("MULTIPOINT ((0 0), (1 1))", 0),
+        ("MULTIPOINT Z ((0 0 0))", 2),
+        ("MULTIPOINT ZM ((0 0 0 0))", 3),
+        ("GEOMETRYCOLLECTION EMPTY", 0),
+        ("GEOMETRYCOLLECTION (POINT Z (0 0 0))", 2),
+        ("GEOMETRYCOLLECTION Z (POINT Z (0 0 0))", 2),
+        ("GEOMETRYCOLLECTION (GEOMETRYCOLLECTION (POINT Z (0 0 0)))", 2),
+    ],
+)
+def test_st_zmflag(eng, geom, expected):
+    eng = eng.create_or_skip()
+    eng.assert_query_result(f"SELECT ST_ZmFlag({geom_or_null(geom)})", expected)

rust/sedona-functions/benches/native-functions.rs

@@ -157,6 +157,9 @@ fn criterion_benchmark(c: &mut Criterion) {
     benchmark::scalar(c, &f, "native", "st_mmin", LineString(10));
     benchmark::scalar(c, &f, "native", "st_mmax", LineString(10));
 
+    benchmark::scalar(c, &f, "native", "st_zmflag", Point);
+    benchmark::scalar(c, &f, "native", "st_zmflag", LineString(10));
+
     benchmark::scalar(
         c,
         &f,

rust/sedona-functions/src/lib.rs

@@ -55,3 +55,4 @@ mod st_transform;
 pub mod st_union_aggr;
 mod st_xyzm;
 mod st_xyzm_minmax;
+mod st_zmflag;

rust/sedona-functions/src/register.rs

@@ -108,6 +108,7 @@ pub fn default_function_set() -> FunctionSet {
         crate::st_xyzm_minmax::st_mmin_udf,
         crate::st_xyzm_minmax::st_mmax_udf,
         crate::st_isclosed::st_isclosed_udf,
+        crate::st_zmflag::st_zmflag_udf,
     );
 
     register_aggregate_udfs!(

rust/sedona-functions/src/st_zmflag.rs

@@ -0,0 +1,193 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+use std::sync::Arc;
+
+use crate::executor::WkbBytesExecutor;
+use arrow_array::builder::Int8Builder;
+use arrow_schema::DataType;
+use datafusion_common::{error::Result, DataFusionError};
+use datafusion_expr::{
+    scalar_doc_sections::DOC_SECTION_OTHER, ColumnarValue, Documentation, Volatility,
+};
+use geo_traits::Dimensions;
+use sedona_common::sedona_internal_err;
+use sedona_expr::scalar_udf::{SedonaScalarKernel, SedonaScalarUDF};
+use sedona_geometry::wkb_header::WkbHeader;
+use sedona_schema::{datatypes::SedonaType, matchers::ArgMatcher};
+
+pub fn st_zmflag_udf() -> SedonaScalarUDF {
+    SedonaScalarUDF::new(
+        "st_zmflag",
+        vec![Arc::new(STZmFlag {})],
+        Volatility::Immutable,
+        Some(st_zmflag_doc()),
+    )
+}
+
+fn st_zmflag_doc() -> Documentation {
+    Documentation::builder(
+        DOC_SECTION_OTHER,
+        "Returns a code indicating the ZM coordinate dimension of a geometry. Values are 0 for 2D, 1 for 3D-M, 2 for 3D-Z, and 3 for 4D.".to_string(),
+        "ST_ZmFlag (A: Geometry)".to_string(),
+    )
+    .with_argument("geom", "geometry: Input geometry")
+    .with_sql_example("SELECT ST_ZmFlag(ST_GeomFromWKT('POLYGON ((0 0, 1 0, 0 1, 0 0))'))")
+    .build()
+}
+
+#[derive(Debug)]
+struct STZmFlag {}
+
+impl SedonaScalarKernel for STZmFlag {
+    fn return_type(&self, args: &[SedonaType]) -> Result<Option<SedonaType>> {
+        let matcher = ArgMatcher::new(
+            vec![ArgMatcher::is_geometry()],
+            SedonaType::Arrow(DataType::Int8),
+        );
+
+        matcher.match_args(args)
+    }
+
+    fn invoke_batch(
+        &self,
+        arg_types: &[SedonaType],
+        args: &[ColumnarValue],
+    ) -> Result<ColumnarValue> {
+        let executor = WkbBytesExecutor::new(arg_types, args);
+        let mut builder = Int8Builder::with_capacity(executor.num_iterations());
+
+        executor.execute_wkb_void(|maybe_item| {
+            match maybe_item {
+                Some(item) => {
+                    builder.append_value(invoke_scalar(item)?);
+                }
+                None => builder.append_null(),
+            }
+            Ok(())
+        })?;
+
+        executor.finish(Arc::new(builder.finish()))
+    }
+}
+
+fn invoke_scalar(buf: &[u8]) -> Result<i8> {
+    let header = WkbHeader::try_new(buf).map_err(|e| DataFusionError::External(Box::new(e)))?;
+    let top_level_dimensions = header
+        .dimensions()
+        .map_err(|e| DataFusionError::External(Box::new(e)))?;
+
+    // Infer dimension based on first coordinate dimension for cases where it differs from top-level
+    // e.g GEOMETRYCOLLECTION (POINT Z (1 2 3))
+    let dimensions;
+    if let Some(first_geom_dimensions) = header.first_geom_dimensions() {
+        dimensions = first_geom_dimensions;
+    } else {
+        dimensions = top_level_dimensions;
+    }
+
+    match dimensions {
+        Dimensions::Xy => Ok(0),
+        Dimensions::Xym => Ok(1),
+        Dimensions::Xyz => Ok(2),
+        Dimensions::Xyzm => Ok(3),
+        _ => sedona_internal_err!("Invalid dimensions: {:?}", dimensions),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use datafusion_common::ScalarValue;
+    use datafusion_expr::ScalarUDF;
+    use rstest::rstest;
+    use sedona_schema::datatypes::{WKB_GEOMETRY, WKB_VIEW_GEOMETRY};
+    use sedona_testing::{
+        fixtures::MULTIPOINT_WITH_INFERRED_Z_DIMENSION_WKB, testers::ScalarUdfTester,
+    };
+
+    use super::*;
+
+    #[test]
+    fn udf_metadata() {
+        let udf: ScalarUDF = st_zmflag_udf().into();
+        assert_eq!(udf.name(), "st_zmflag");
+        assert!(udf.documentation().is_some());
+    }
+
+    #[rstest]
+    fn udf(#[values(WKB_GEOMETRY, WKB_VIEW_GEOMETRY)] sedona_type: SedonaType) {
+        let tester = ScalarUdfTester::new(st_zmflag_udf().into(), vec![sedona_type.clone()]);
+
+        tester.assert_return_type(DataType::Int8);
+
+        let result = tester.invoke_scalar("POINT ZM (1 2 3 4)").unwrap();
+        tester.assert_scalar_result_equals(result, 3);
+
+        let result = tester.invoke_scalar("POINT (1 2)").unwrap();
+        tester.assert_scalar_result_equals(result, 0);
+
+        let result = tester.invoke_scalar("POINT Z (1 2 3)").unwrap();
+        tester.assert_scalar_result_equals(result, 2);
+
+        let result = tester.invoke_wkb_scalar(None).unwrap();
+        tester.assert_scalar_result_equals(result, ScalarValue::Null);
+
+        // Z-dimension specified only in the nested geometry, but not the geom collection level
+        let result = tester
+            .invoke_wkb_scalar(Some("GEOMETRYCOLLECTION (POINT Z (1 2 3))"))
+            .unwrap();
+        tester.assert_scalar_result_equals(result, 2);
+
+        // Z-dimension specified on both the geom collection and nested geometry level
+        // Geometry collection with Z dimension both on the geom collection and nested geometry level
+        let result = tester
+            .invoke_wkb_scalar(Some("GEOMETRYCOLLECTION Z (POINT Z (1 2 3))"))
+            .unwrap();
+        tester.assert_scalar_result_equals(result, 2);
+
+        let result = tester
+            .invoke_wkb_scalar(Some("GEOMETRYCOLLECTION (POINT M (1 2 3))"))
+            .unwrap();
+        tester.assert_scalar_result_equals(result, 1);
+
+        let result = tester
+            .invoke_wkb_scalar(Some("GEOMETRYCOLLECTION EMPTY"))
+            .unwrap();
+        tester.assert_scalar_result_equals(result, 0);
+
+        // Empty geometry collections with Z or M dimensions
+        let result = tester
+            .invoke_wkb_scalar(Some("GEOMETRYCOLLECTION Z EMPTY"))
+            .unwrap();
+        tester.assert_scalar_result_equals(result, 2);
+
+        let result = tester
+            .invoke_wkb_scalar(Some("GEOMETRYCOLLECTION M EMPTY"))
+            .unwrap();
+        tester.assert_scalar_result_equals(result, 1);
+    }
+
+    #[test]
+    fn multipoint_with_inferred_z_dimension() {
+        let tester = ScalarUdfTester::new(st_zmflag_udf().into(), vec![WKB_GEOMETRY]);
+
+        let scalar = ScalarValue::Binary(Some(MULTIPOINT_WITH_INFERRED_Z_DIMENSION_WKB.to_vec()));
+        assert_eq!(
+            tester.invoke_scalar(scalar.clone()).unwrap(),
+            ScalarValue::Int8(Some(2))
+        );
+    }
+}