petern48 commented on code in PR #171:
URL: https://github.com/apache/sedona-db/pull/171#discussion_r2400821600
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rust/sedona-functions/src/st_haszm.rs:
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@@ -107,28 +107,63 @@ impl SedonaScalarKernel for STHasZm {
}
}
-fn invoke_scalar(item: &Wkb, dim_index: usize) -> Result<Option<bool>> {
- match item.as_type() {
- geo_traits::GeometryType::GeometryCollection(collection) => {
- use geo_traits::GeometryCollectionTrait;
- if collection.num_geometries() == 0 {
- Ok(Some(false))
- } else {
- // PostGIS doesn't allow creating a GeometryCollection with
geometries of different dimensions
- // so we can just check the dimension of the first one
- let first_geom = unsafe { collection.geometry_unchecked(0) };
- invoke_scalar(first_geom, dim_index)
- }
- }
- _ => {
- let geom_dim = item.dim();
- match dim_index {
- 2 => Ok(Some(matches!(geom_dim, Dimensions::Xyz |
Dimensions::Xyzm))),
- 3 => Ok(Some(matches!(geom_dim, Dimensions::Xym |
Dimensions::Xyzm))),
- _ => sedona_internal_err!("unexpected dim_index"),
- }
+/// Fast-path inference of geometry type name from raw WKB bytes
+/// An error will be thrown for invalid WKB bytes input
+///
+/// Spec: https://libgeos.org/specifications/wkb/
+fn infer_haszm(buf: &[u8], dim_index: usize) -> Result<Option<bool>> {
+ if buf.len() < 5 {
+ return sedona_internal_err!("Invalid WKB: buffer too small ({}
bytes)", buf.len());
+ }
+
+ let byte_order = buf[0];
+ let code = match byte_order {
+ 0 => u32::from_be_bytes([buf[1], buf[2], buf[3], buf[4]]),
+ 1 => u32::from_le_bytes([buf[1], buf[2], buf[3], buf[4]]),
+ other => return sedona_internal_err!("Unexpected byte order: {other}"),
+ };
+
+ // 0000 -> xy or unspecified
+ // 1000 -> xyz
+ // 2000 -> xym
+ // 3000 -> xyzm
+ match code / 1000 {
+ // If xy, it's possible we need to infer the dimension
+ 0 => {}
+ 1 => return Ok(Some(dim_index == 2)),
+ 2 => return Ok(Some(dim_index == 3)),
+ 3 => return Ok(Some(true)),
+ _ => return sedona_internal_err!("Unexpected code: {code}"),
+ };
+
+ // If GeometryCollection (7), we need to check the dimension of the first
geometry
+ if code & 0x7 == 7 {
+ // The next 4 bytes are the number of geometries in the collection
+ let num_geometries = match byte_order {
+ 0 => u32::from_be_bytes([buf[5], buf[6], buf[7], buf[8]]),
+ 1 => u32::from_le_bytes([buf[5], buf[6], buf[7], buf[8]]),
+ other => return sedona_internal_err!("Unexpected byte order:
{other}"),
+ };
+ // Check the dimension of the first geometry since they all have to be
the same dimension
+ // Note: Attempting to create the following geometries error and are
thus not possible to create:
+ // - Nested geometry dimension doesn't match the **specified** geom
collection z-dimension
+ // - GEOMETRYCOLLECTION M (POINT Z (1 1 1))
+ // - Nested geometry doesn't have the specified dimension
+ // - GEOMETRYCOLLECTION Z (POINT (1 1))
+ // - Nested geometries have different dimensions
+ // - GEOMETRYCOLLECTION (POINT Z (1 1 1), POINT (1 1))
+ if num_geometries >= 1 {
+ return infer_haszm(&buf[9..], dim_index);
}
+ // If empty geometry (num_geometries == 0), fallback to below logic to
check the geom collection's dimension
+ // GEOMETRY COLLECTION Z EMPTY hasz -> true
}
+
+ // TODO: Last check: check how many dimensions the 1st coordinate has (all
other coordinates must have the same)
+ // e.g handle this case: POINT (0 0 0) -> xyz dimension, POINT (0 0 0 0)
-> xyzm dimension
Review Comment:
Based on what you're saying, this logic be unnecessary, so I will remove it.
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