In easycsv_print_columns/rows, check NULL pointer

Signed-off-by: Pradana AUMARS <paumars@courrier.dev>

src/easycsv.c

@@ -240,13 +240,23 @@ easycsv_read_value(const easycsv *csv,
 int
 easycsv_print_rows(const easycsv *csv)
 {
-  return csv->rows;
+  if (csv != NULL) {
+    return csv->rows;
+  }
+  else {
+    return -1;
+  }
 }
 
 int
 easycsv_print_columns(const easycsv *csv)
 {
-  return csv->cols;
+  if (csv != NULL) {
+    return csv->cols;
+  }
+  else {
+    return -1;
+  }
 }
 
 /*** Modifications, sort ***/