Fix create_arange empty range (#604)

* Fix create_arange crashing when stop == start

This is due to len being equal to zero, which made (len - 1) equal to MAX_UINT16

* trailing whitespaces

Author: FelixNumworks

code/numpy/create.c

@@ -159,7 +159,7 @@ mp_obj_t create_arange(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_arg
     }
 
     ndarray_obj_t *ndarray;
-    if((stop - start)/step < 0) {
+    if((stop - start)/step <= 0) {
         ndarray = ndarray_new_linear_array(0, dtype);
     } else {
         size_t len = (size_t)(MICROPY_FLOAT_C_FUN(ceil)((stop - start) / step));
@@ -254,14 +254,14 @@ mp_obj_t create_concatenate(size_t n_args, const mp_obj_t *pos_args, mp_map_t *k
     size_t *shape = m_new0(size_t, ULAB_MAX_DIMS);
     mp_obj_tuple_t *ndarrays = MP_OBJ_TO_PTR(args[0].u_obj);
 
-    // first check, whether 
+    // first check, whether
 
     for(uint8_t i = 0; i < ndarrays->len; i++) {
         if(!mp_obj_is_type(ndarrays->items[i], &ulab_ndarray_type)) {
             mp_raise_ValueError(translate("only ndarrays can be concatenated"));
         }
     }
-    
+
     // first check, whether the arrays are compatible
     ndarray_obj_t *_ndarray = MP_OBJ_TO_PTR(ndarrays->items[0]);
     uint8_t dtype = _ndarray->dtype;

code/ulab.c

@@ -33,7 +33,7 @@
 #include "user/user.h"
 #include "utils/utils.h"
 
-#define ULAB_VERSION 6.0.7
+#define ULAB_VERSION 6.0.8
 #define xstr(s) str(s)
 #define str(s) #s
 

tests/2d/numpy/arange.py

@@ -9,9 +9,11 @@
     print(np.arange(10, dtype=dtype))
     print(np.arange(2, 10, dtype=dtype))
     print(np.arange(2, 10, 3, dtype=dtype))
+    # test empty range
+    print(np.arange(0, 0, dtype=dtype))
 
 # test for ZeroDivisionError exception
 try:
     np.arange(0, 10, 0)
 except ZeroDivisionError as e:
-    print('ZeroDivisionError: ', e)
+    print('ZeroDivisionError: ', e)

tests/2d/numpy/arange.py.exp

@@ -1,16 +1,21 @@
 array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9], dtype=uint8)
 array([2, 3, 4, 5, 6, 7, 8, 9], dtype=uint8)
 array([2, 5, 8], dtype=uint8)
+array([], dtype=uint8)
 array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9], dtype=int8)
 array([2, 3, 4, 5, 6, 7, 8, 9], dtype=int8)
 array([2, 5, 8], dtype=int8)
+array([], dtype=int8)
 array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9], dtype=uint16)
 array([2, 3, 4, 5, 6, 7, 8, 9], dtype=uint16)
 array([2, 5, 8], dtype=uint16)
+array([], dtype=uint16)
 array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9], dtype=int16)
 array([2, 3, 4, 5, 6, 7, 8, 9], dtype=int16)
 array([2, 5, 8], dtype=int16)
+array([], dtype=int16)
 array([0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0], dtype=float64)
 array([2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0], dtype=float64)
 array([2.0, 5.0, 8.0], dtype=float64)
+array([], dtype=float64)
 ZeroDivisionError:  divide by zero