Rust things

server-rs/src/aggregation.rs

@@ -1,5 +1,5 @@
 use crate::consts::NAN_U16;
-use crate::data::QuantRef;
+use crate::data::{PostcodePoiMetrics, QuantRef};
 
 /// Optional per-enum-value distribution tracking for a single feature.
 /// Counts how many rows have each enum value (by raw u16 index).
@@ -21,6 +21,69 @@ pub struct Aggregator {
     pub enum_dist: Option<EnumDist>,
 }
 
+/// Accumulator for postcode-level POI metrics stored outside `feature_data`.
+/// Only constructed when a request selects POI metric fields.
+pub struct PoiAggregator {
+    pub mins: Box<[f32]>,
+    pub maxs: Box<[f32]>,
+    pub sums: Box<[f64]>,
+    pub counts: Box<[u32]>,
+}
+
+impl PoiAggregator {
+    pub fn new(num_features: usize) -> Self {
+        Self {
+            mins: vec![f32::INFINITY; num_features].into_boxed_slice(),
+            maxs: vec![f32::NEG_INFINITY; num_features].into_boxed_slice(),
+            sums: vec![0.0f64; num_features].into_boxed_slice(),
+            counts: vec![0u32; num_features].into_boxed_slice(),
+        }
+    }
+
+    #[inline]
+    pub fn add_row_selective(
+        &mut self,
+        poi_metrics: &PostcodePoiMetrics,
+        row: usize,
+        indices: &[usize],
+    ) {
+        let Some(metric_row) = poi_metrics.metric_row_for_property(row) else {
+            return;
+        };
+        for &metric_idx in indices {
+            let raw = poi_metrics.raw_for_metric_row(metric_row, metric_idx);
+            if raw == NAN_U16 {
+                continue;
+            }
+            let value = poi_metrics.decode_raw(metric_idx, raw);
+            if value < self.mins[metric_idx] {
+                self.mins[metric_idx] = value;
+            }
+            if value > self.maxs[metric_idx] {
+                self.maxs[metric_idx] = value;
+            }
+            self.sums[metric_idx] += value as f64;
+            self.counts[metric_idx] += 1;
+        }
+    }
+
+    pub fn merge(&mut self, other: &PoiAggregator) {
+        for i in 0..self.counts.len() {
+            if other.counts[i] == 0 {
+                continue;
+            }
+            if other.mins[i] < self.mins[i] {
+                self.mins[i] = other.mins[i];
+            }
+            if other.maxs[i] > self.maxs[i] {
+                self.maxs[i] = other.maxs[i];
+            }
+            self.sums[i] += other.sums[i];
+            self.counts[i] += other.counts[i];
+        }
+    }
+}
+
 /// Configuration for enum distribution tracking, passed to Aggregator::new.
 /// (feature_index, number_of_enum_values)
 pub type EnumDistConfig = Option<(usize, usize)>;