fix: placement.rs — actual_col==0 时下溢保护

core/src/matrix/placement.rs

@@ -34,6 +34,7 @@ pub fn place_data(matrix: &mut Matrix, codewords: &[u8]) {
                 if bit_idx >= bits.len() {
                     break;
                 }
+                if actual_col > 0 {
                     place_bit(
                         matrix,
                         (actual_col - 1) as u8,
@@ -42,6 +43,7 @@ pub fn place_data(matrix: &mut Matrix, codewords: &[u8]) {
                         &mut bit_idx,
                     );
                 }
+            }
         } else {
             for row in 0..size {
                 if bit_idx >= bits.len() {
@@ -57,6 +59,7 @@ pub fn place_data(matrix: &mut Matrix, codewords: &[u8]) {
                 if bit_idx >= bits.len() {
                     break;
                 }
+                if actual_col > 0 {
                     place_bit(
                         matrix,
                         (actual_col - 1) as u8,
@@ -66,6 +69,7 @@ pub fn place_data(matrix: &mut Matrix, codewords: &[u8]) {
                     );
                 }
             }
+        }
 
         col -= 2;
         going_up = !going_up;