Undo BPTree simplification.

prrt/util/bptree.c

@@ -1062,7 +1062,14 @@ void *BPTree_get_first_in_range(BPTreeNode *root, BPTreeKey_t key_start, BPTreeK
     if (n == NULL) return NULL;
     for (i = 0; i < n->num_keys && n->keys[i] < key_start; i++);
     if (i == n->num_keys) return NULL;
-    return ((BPTreeRecord *) n->pointers[i])->value;
+    while (n != NULL) {
+        for (; i < n->num_keys && n->keys[i] <= key_end; i++) {
+            return ((BPTreeRecord *) n->pointers[i])->value;
+        }
+        n = n->pointers[order - 1];
+        i = 0;
+    }
+    return NULL;
 }
 
 uint32_t BPTree_size(BPTreeNode *root) {