对齐 AiQuant RQAlpha 回测语义

crates/fidc-core/src/data.rs

@@ -654,6 +654,14 @@ impl SymbolPriceSeries {
         self.values_for(field).get(end - 1).copied()
     }
 
+    fn snapshot_before(&self, date: NaiveDate) -> Option<&DailyMarketSnapshot> {
+        let end = self.previous_completed_end_index(date)?;
+        if end == 0 {
+            return None;
+        }
+        self.snapshots.get(end - 1)
+    }
+
     fn prefix_for(&self, field: PriceField) -> &[f64] {
         match field {
             PriceField::DayOpen => &self.open_prefix,
@@ -1828,6 +1836,12 @@ impl DataSet {
             .and_then(|series| series.price_on_or_before(date, field))
     }
 
+    pub fn market_before(&self, date: NaiveDate, symbol: &str) -> Option<&DailyMarketSnapshot> {
+        self.market_series_by_symbol
+            .get(symbol)
+            .and_then(|series| series.snapshot_before(date))
+    }
+
     pub fn factor_snapshots_on(&self, date: NaiveDate) -> Vec<&DailyFactorSnapshot> {
         self.factor_by_date
             .get(&date)