[RTL] Refactoring of realloc initialization

src/plugins/e-acsl/share/e-acsl/adt_models/e_acsl_adt_mmodel.h

@@ -170,26 +170,10 @@ void* __realloc(void* ptr, size_t size) {
       int nb = needed_bytes(size);
       /* Number of bits that need to be set in tmp->init_ptr */
       int nb_old = needed_bytes(tmp->size);
-
-      /* Allocate tmp->init_ptr that tracks partial initialization and fully
-       * set nb_old bytes. Note that nb_old is not a multiple of 8 (i.e., bit
-       * size of a byte), the last (8 - old_size%8) bits of the last byte in
-       * tmp->init_ptr need to be unset. E.g., if the old size is 11 and the
-       * new size if 14 then tmp->init_ptr is 2 bytes and last 5 bits of
-       * tmp->init_ptr[1] should be unset. */
-      tmp->init_ptr = native_malloc(nb);
-      memset(tmp->init_ptr, 0xFF, nb_old);
-
-      /* Adjust bits in the last byte */
-      if(tmp->size%8 != 0) {
-        /* Get a fully initialized byte (255), shift right by the number
-         * of bytes that need to be pertained and flip, so zeroes becomes
-         * one and vice versa. E.g., in the above example this is as follows:
-         *  1111 1111   -    255
-         *  0001 1111   -    255 << tmp->size%8
-         *  1110 0000   -    ~(255 << tmp->size%8) */
-        tmp->init_ptr[tmp->size/8] &= ~(255 << tmp->size%8);
-      }
+      /* Allocate memory to store partial initialization */
+      tmp->init_ptr = native_calloc(1, nb);
+      /* Carry out initialization of the old block */
+      bitwise_memset(tmp->init_ptr, tmp->size, 1, 0);
     }
   }
   /* contains initialized and uninitialized parts */