diff --git a/rust/hg-core/src/revlog/index.rs b/rust/hg-core/src/revlog/index.rs
--- a/rust/hg-core/src/revlog/index.rs
+++ b/rust/hg-core/src/revlog/index.rs
@@ -21,7 +21,7 @@
             let mut offset: usize = 0;
             let mut offsets = Vec::new();
 
-            while (bytes.len() - offset) >= INDEX_ENTRY_SIZE {
+            while INDEX_ENTRY_SIZE + offset <= bytes.len() {
                 offsets.push(offset);
                 let end = offset + INDEX_ENTRY_SIZE;
                 let entry = IndexEntry {