factor offset values

grovedb/src/operations/proof/generate.rs

@@ -47,7 +47,7 @@ use grovedb_storage::StorageContext;
 use crate::{
     element::helpers::raw_decode,
     operations::proof::util::{
-        increase_limit_by, reduce_limit_and_offset_by, write_slice_of_slice_to_slice,
+        increase_limit_and_offset_by, reduce_limit_and_offset_by, write_slice_of_slice_to_slice,
         write_slice_to_vec, write_to_vec, ProofTokenType, EMPTY_TREE_HASH,
     },
     reference_path::path_from_reference_path_type,
@@ -215,7 +215,9 @@ impl GroveDb {
         }
 
         let mut is_leaf_tree = true;
-        let mut leaf_element_count = 0;
+
+        let mut offset_inc = 0;
+        let mut limit_inc = 0;
 
         let mut kv_iterator = KVIterator::new(subtree.storage.raw_iter(), &query.query.query)
             .unwrap_add_cost(&mut cost);
@@ -232,8 +234,13 @@ impl GroveDb {
                     if subquery_value.is_none() && subquery_path.is_none() {
                         // this element should be added to the result set
                         // hence we have to update the limit and offset value
-                        reduce_limit_and_offset_by(current_limit, current_offset, 1);
-                        leaf_element_count += 1;
+                        let reduced_offset =
+                            reduce_limit_and_offset_by(current_limit, current_offset, 1);
+                        if reduced_offset {
+                            offset_inc += 1;
+                        } else {
+                            limit_inc += 1;
+                        }
                         continue;
                     }
 
@@ -413,7 +420,7 @@ impl GroveDb {
         if is_leaf_tree {
             // if no useful subtree, then we care about the result set of this subtree.
             // apply the sized query
-            increase_limit_by(current_limit, leaf_element_count);
+            increase_limit_and_offset_by(current_limit, current_offset, limit_inc, offset_inc);
             let limit_offset = cost_return_on_error!(
                 &mut cost,
                 self.generate_and_store_merk_proof(

grovedb/src/operations/proof/util.rs

@@ -333,9 +333,17 @@ pub fn reduce_limit_and_offset_by(
     skip_limit
 }
 
-pub fn increase_limit_by(limit: &mut Option<u16>, n: u16) {
+pub fn increase_limit_and_offset_by(
+    limit: &mut Option<u16>,
+    offset: &mut Option<u16>,
+    limit_inc: u16,
+    offset_inc: u16,
+) {
+    if let Some(offset_value) = *offset {
+        *offset = Some(offset_value + offset_inc);
+    }
     if let Some(limit_value) = *limit {
-        *limit = Some(limit_value + n);
+        *limit = Some(limit_value + limit_inc);
     }
 }