sapienza88 commented on code in PR #777: URL: https://github.com/apache/sedona-db/pull/777#discussion_r3250394265
########## rust/sedona-functions/src/st_linesubstring.rs: ########## @@ -0,0 +1,205 @@ +// 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 crate::executor::WkbExecutor; +use arrow_array::builder::BinaryBuilder; +use arrow_schema::DataType; +use datafusion_common::{error::Result, DataFusionError, ScalarValue}; +use datafusion_expr::{ColumnarValue, Volatility}; +use geo_traits::{CoordTrait, Dimensions, GeometryTrait, GeometryType, LineStringTrait}; +use sedona_expr::{ + item_crs::ItemCrsKernel, + scalar_udf::{SedonaScalarKernel, SedonaScalarUDF}, +}; +use sedona_geometry::error::SedonaGeometryError; +use sedona_geometry::wkb_factory::write_wkb_coord_trait; +use sedona_schema::{ + datatypes::{SedonaType, WKB_GEOMETRY}, + matchers::ArgMatcher, +}; +use std::{io::Write, sync::Arc}; + +#[derive(Debug)] +struct STLineSubstring; +pub fn st_line_substring_udf() -> SedonaScalarUDF { + SedonaScalarUDF::new( + "st_linesubstring", + ItemCrsKernel::wrap_impl(vec![Arc::new(STLineSubstring)]), + Volatility::Immutable, + ) +} + +impl SedonaScalarKernel for STLineSubstring { + fn return_type(&self, args: &[SedonaType]) -> Result<Option<SedonaType>> { + let matcher = ArgMatcher::new( + vec![ + ArgMatcher::is_geometry(), + ArgMatcher::is_numeric(), + ArgMatcher::is_numeric(), + ], + WKB_GEOMETRY, + ); + matcher.match_args(args) + } + + fn invoke_batch( + &self, + arg_types: &[SedonaType], + args: &[ColumnarValue], + ) -> Result<ColumnarValue> { + let executor = WkbExecutor::new(arg_types, args); + let mut builder = BinaryBuilder::new(); + + let start_frac: Option<f64> = match &args[1].cast_to(&DataType::Float64, None)? { + ColumnarValue::Scalar(ScalarValue::Float64(s)) => *s, + _ => None, + }; + + let end_frac: Option<f64> = match &args[2].cast_to(&DataType::Float64, None)? { + ColumnarValue::Scalar(ScalarValue::Float64(e)) => *e, + _ => None, + }; + + unsafe fn interpolate<C: CoordTrait<T = f64>>( + p1: C, + p2: C, + fraction: f64, + dim: Dimensions, + buf: &mut impl Write, + ) -> Result<(), SedonaGeometryError> { + for i in 0..dim.size() { + let v = + p1.nth_unchecked(i) + (p2.nth_unchecked(i) - p1.nth_unchecked(i)) * fraction; + buf.write_all(&v.to_le_bytes())?; + } + Ok(()) + } + + executor.execute_wkb_void(|maybe_wkb| unsafe { + let mut wkb_body = Vec::new(); + let mut point_count = 0u32; + + let (s_f, e_f) = match (start_frac, end_frac) { + (Some(s), Some(e)) => (s, e), + _ => { + builder.append_null(); + return Ok(()); + } + }; + + if let Some(wkb) = maybe_wkb { + if let GeometryType::LineString(line) = wkb.as_type() { + let num_coords = line.num_coords(); + let dim = line.dim(); + + let mut cumulative_distances = Vec::with_capacity(num_coords); + let mut total_length = 0.0; + cumulative_distances.push(0.0); + + for i in 0..(num_coords - 1) { + let p1 = line.coord(i).unwrap(); + let p2 = line.coord(i + 1).unwrap(); + let dist = ((p2.x() - p1.x()).powi(2) + (p2.y() - p1.y()).powi(2)).sqrt(); + total_length += dist; + cumulative_distances.push(total_length); + } + + let start_dist = s_f * total_length; + let end_dist = e_f * total_length; + + for i in 0..(num_coords - 1) { + let d1 = cumulative_distances[i]; + let d2 = cumulative_distances[i + 1]; + let p1 = line.coord(i).unwrap(); + let p2 = line.coord(i + 1).unwrap(); + + if start_dist >= d1 && start_dist <= d2 { + let segment_len = d2 - d1; + let fraction = if segment_len > 0.0 { + (start_dist - d1) / segment_len + } else { + 0.0 + }; + interpolate(p1, p2, fraction, dim, &mut wkb_body).map_err(|e| { + DataFusionError::Internal(format!( + "Sedona interpolation failed: {}", + e + )) + })?; + point_count += 1; + } + + if d1 > start_dist && d1 < end_dist { + write_wkb_coord_trait(&mut wkb_body, &p1).map_err(|e| { + DataFusionError::Internal(format!("WKB write failed: {}", e)) + })?; + point_count += 1; + } + + if end_dist >= d1 && end_dist <= d2 { + let segment_len = d2 - d1; + let fraction = if segment_len > 0.0 { + (end_dist - d1) / segment_len + } else { + 0.0 + }; + interpolate(p1, p2, fraction, dim, &mut wkb_body).map_err(|e| { + DataFusionError::Internal(format!( + "Sedona interpolation failed: {}", + e + )) + })?; + point_count += 1; + } + } + + // 2. Build Header inside the 'line' scope (Fixes "cannot find dim/line") + if point_count > 0 { + let mut final_wkb = Vec::new(); + final_wkb.push(1u8); // Little Endian + + if s_f == e_f { + // POINT Result (Fixes point vs line test) + let p_type: u32 = if dim == Dimensions::Xyz { 1001 } else { 1 }; + final_wkb.extend_from_slice(&p_type.to_le_bytes()); + let coord_bytes = dim.size() * 8; + if wkb_body.len() >= coord_bytes { + final_wkb.extend_from_slice(&wkb_body[..coord_bytes]); + } + } else { + // LINESTRING Result (Fixes Z-coordinate drop) + let l_type: u32 = if dim == Dimensions::Xyz { 1002 } else { 2 }; + final_wkb.extend_from_slice(&l_type.to_le_bytes()); + final_wkb.extend_from_slice(&point_count.to_le_bytes()); + final_wkb.extend_from_slice(&wkb_body); + } Review Comment: done! -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. 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