Merge 650c85ccd7 into 931a33642e

core/storage/btree.rs

@@ -445,16 +445,16 @@ pub enum CursorSeekState {
 }
 
 #[derive(Debug)]
-struct FindCellState(Option<isize>);
+struct FindCellState(Option<(usize, usize)>); // low, high
 
 impl FindCellState {
     #[inline]
-    fn set(&mut self, cell_idx: isize) {
-        self.0 = Some(cell_idx)
+    fn set(&mut self, lowhigh: (usize, usize)) {
+        self.0 = Some(lowhigh);
     }
 
     #[inline]
-    fn get_cell_idx(&mut self) -> isize {
+    fn get_state(&mut self) -> (usize, usize) {
         self.0.expect("get can only be called after a set")
     }
 
@@ -3863,32 +3863,30 @@ impl BTreeCursor {
 
     /// Find the index of the cell in the page that contains the given rowid.
     fn find_cell(&mut self, page: &PageContent, key: &BTreeKey) -> Result<CursorResult<usize>> {
-        if self.find_cell_state.0.is_none() {
-            self.find_cell_state.set(0);
-        }
         let cell_count = page.cell_count();
-        while self.find_cell_state.get_cell_idx() < cell_count as isize {
-            assert!(self.find_cell_state.get_cell_idx() >= 0);
-            let cell_idx = self.find_cell_state.get_cell_idx() as usize;
-            match page
-                .cell_get(
-                    cell_idx,
-                    payload_overflow_threshold_max(page.page_type(), self.usable_space() as u16),
-                    payload_overflow_threshold_min(page.page_type(), self.usable_space() as u16),
-                    self.usable_space(),
-                )
-                .unwrap()
-            {
-                BTreeCell::TableLeafCell(cell) => {
-                    if key.to_rowid() <= cell._rowid {
-                        break;
-                    }
-                }
-                BTreeCell::TableInteriorCell(cell) => {
-                    if key.to_rowid() <= cell._rowid {
-                        break;
-                    }
-                }
+        let mut low = 0;
+        let mut high = if cell_count > 0 { cell_count - 1 } else { 0 };
+        let mut result_index = cell_count;
+        if self.find_cell_state.0.is_some() {
+            (low, high) = self.find_cell_state.get_state();
+        }
+
+        while low <= high && cell_count > 0 {
+            let mid = low + (high - low) / 2;
+            self.find_cell_state.set((low, high));
+            let cell = match page.cell_get(
+                mid,
+                payload_overflow_threshold_max(page.page_type(), self.usable_space() as u16),
+                payload_overflow_threshold_min(page.page_type(), self.usable_space() as u16),
+                self.usable_space(),
+            ) {
+                Ok(c) => c,
+                Err(e) => return Err(e),
+            };
+
+            let comparison_result = match cell {
+                BTreeCell::TableLeafCell(cell) => key.to_rowid().cmp(&cell._rowid),
+                BTreeCell::TableInteriorCell(cell) => key.to_rowid().cmp(&cell._rowid),
                 BTreeCell::IndexInteriorCell(IndexInteriorCell {
                     payload,
                     first_overflow_page,
@@ -3899,41 +3897,51 @@ impl BTreeCursor {
                     payload,
                     first_overflow_page,
                     payload_size,
+                    ..
                 }) => {
                     // TODO: implement efficient comparison of records
                     // e.g. https://github.com/sqlite/sqlite/blob/master/src/vdbeaux.c#L4719
                     return_if_io!(self.read_record_w_possible_overflow(
                         payload,
                         first_overflow_page,
-                        payload_size,
+                        payload_size
                     ));
+
                     let key_values = key.to_index_key_values();
                     let record = self.get_immutable_record();
                     let record = record.as_ref().unwrap();
                     let record_same_number_cols = &record.get_values()[..key_values.len()];
-                    let order = compare_immutable(
+                    compare_immutable(
                         key_values,
                         record_same_number_cols,
                         self.key_sort_order(),
                         &self.collations,
-                    );
-                    match order {
-                        Ordering::Less | Ordering::Equal => {
-                            break;
-                        }
-                        Ordering::Greater => {}
+                    )
+                }
+            };
+
+            match comparison_result {
+                Ordering::Equal => {
+                    result_index = mid;
+                    break;
+                }
+                Ordering::Greater => {
+                    low = mid + 1;
+                }
+                Ordering::Less => {
+                    result_index = mid;
+                    if mid == 0 {
+                        break;
                     }
+                    high = mid - 1;
                 }
             }
-            let cell_idx = self.find_cell_state.get_cell_idx();
-            self.find_cell_state.set(cell_idx + 1);
         }
-        let cell_idx = self.find_cell_state.get_cell_idx();
-        assert!(cell_idx >= 0);
-        let cell_idx = cell_idx as usize;
-        assert!(cell_idx <= cell_count);
+
         self.find_cell_state.reset();
-        Ok(CursorResult::Ok(cell_idx))
+        assert!(result_index <= cell_count);
+
+        Ok(CursorResult::Ok(result_index))
     }
 
     pub fn seek_end(&mut self) -> Result<CursorResult<()>> {