From 536c35b1a57941f2bfa0ac96ad9e3a9cf4d52f48 Mon Sep 17 00:00:00 2001
From: Rostyslav Tyshko <tyshko.rostyslav@gmail.com>
Date: Thu, 5 Jun 2025 22:49:12 -0400
Subject: [PATCH] add produce_blob_list_from_sc_public_state and
 compare_blob_lists to newely created blob_utils

---
 sc_core/src/blob_utils.rs | 82 +++++++++++++++++++++++++++++++++++++++
 sc_core/src/lib.rs        |  1 +
 2 files changed, 83 insertions(+)
 create mode 100644 sc_core/src/blob_utils.rs

diff --git a/sc_core/src/blob_utils.rs b/sc_core/src/blob_utils.rs
new file mode 100644
index 0000000..5da5625
--- /dev/null
+++ b/sc_core/src/blob_utils.rs
@@ -0,0 +1,82 @@
+use serde::Serialize;
+use storage::{sc_db_utils::{produce_blob_from_fit_vec, DataBlob, DataBlobChangeVariant}, SC_DATA_BLOB_SIZE};
+
+///Creates blob list from generic serializable state
+///
+///`ToDo`: Find a way to align data in a way, to minimize read and write operations in db
+pub fn produce_blob_list_from_sc_public_state<S: Serialize>(
+    state: &S,
+) -> Result<Vec<DataBlob>, serde_json::Error> {
+    let mut blob_list = vec![];
+
+    let ser_data = serde_json::to_vec(state)?;
+
+    //`ToDo` Replace with `next_chunk` usage, when feature stabilizes in Rust
+    for i in 0..=(ser_data.len() / SC_DATA_BLOB_SIZE) {
+        let next_chunk: Vec<u8>;
+
+        if (i + 1) * SC_DATA_BLOB_SIZE < ser_data.len() {
+            next_chunk = ser_data[(i * SC_DATA_BLOB_SIZE)..((i + 1) * SC_DATA_BLOB_SIZE)]
+                .iter()
+                .cloned()
+                .collect();
+        } else {
+            next_chunk = ser_data[(i * SC_DATA_BLOB_SIZE)..(ser_data.len())]
+                .iter()
+                .cloned()
+                .collect();
+        }
+
+        blob_list.push(produce_blob_from_fit_vec(next_chunk));
+    }
+
+    Ok(blob_list)
+}
+
+///Compare two consecutive in time blob lists to produce list of modified ids
+pub fn compare_blob_lists(
+    blob_list_old: &[DataBlob],
+    blob_list_new: &[DataBlob],
+) -> Vec<DataBlobChangeVariant> {
+    let mut changed_ids = vec![];
+    let mut id_end = 0;
+
+    let old_len = blob_list_old.len();
+    let new_len = blob_list_new.len();
+
+    if old_len > new_len {
+        for id in new_len..old_len {
+            changed_ids.push(DataBlobChangeVariant::Deleted { id });
+        }
+    } else if new_len > old_len {
+        for id in old_len..new_len {
+            changed_ids.push(DataBlobChangeVariant::Created {
+                id,
+                blob: blob_list_new[id],
+            });
+        }
+    }
+
+    loop {
+        let old_blob = blob_list_old.get(id_end);
+        let new_blob = blob_list_new.get(id_end);
+
+        match (old_blob, new_blob) {
+            (Some(old), Some(new)) => {
+                if old != new {
+                    changed_ids.push(DataBlobChangeVariant::Modified {
+                        id: id_end,
+                        blob_old: *old,
+                        blob_new: *new,
+                    });
+                }
+            }
+            _ => break,
+        }
+
+        id_end += 1;
+    }
+
+    changed_ids
+}
+
diff --git a/sc_core/src/lib.rs b/sc_core/src/lib.rs
index ed7f610..d8f690a 100644
--- a/sc_core/src/lib.rs
+++ b/sc_core/src/lib.rs
@@ -3,3 +3,4 @@ pub mod proofs_circuits;
 pub mod traits;
 pub mod transaction_payloads_tools;
 pub mod public_context;
+pub mod blob_utils;