Skip to content

Commit 9b7a8ee

Browse files
dpgeorgedpgeorge
committed
py: Fix mult by negative number of tuple, list, str, bytes.
Multiplication of a tuple, list, str or bytes now yields an empty sequence (instead of crashing). Addresses issue adafruit#799 Also added ability to mult bytes on LHS by integer.
1 parent 9d02780 commit 9b7a8ee

8 files changed

Lines changed: 59 additions & 7 deletions

File tree

‎py/objint.c‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -289,7 +289,7 @@ mp_obj_t mp_obj_int_binary_op_extra_cases(int op, mp_obj_t lhs_in, mp_obj_t rhs_
289289
// true acts as 0
290290
return mp_binary_op(op, lhs_in, MP_OBJ_NEW_SMALL_INT(1));
291291
} else if (op == MP_BINARY_OP_MULTIPLY) {
292-
if (MP_OBJ_IS_STR(rhs_in) || MP_OBJ_IS_TYPE(rhs_in, &mp_type_tuple) || MP_OBJ_IS_TYPE(rhs_in, &mp_type_list)) {
292+
if (MP_OBJ_IS_STR(rhs_in) || MP_OBJ_IS_TYPE(rhs_in, &mp_type_bytes) || MP_OBJ_IS_TYPE(rhs_in, &mp_type_tuple) || MP_OBJ_IS_TYPE(rhs_in, &mp_type_list)) {
293293
// multiply is commutative for these types, so delegate to them
294294
return mp_binary_op(op, rhs_in, lhs_in);
295295
}

‎py/objlist.c‎

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -131,6 +131,9 @@ STATIC mp_obj_t list_binary_op(int op, mp_obj_t lhs, mp_obj_t rhs) {
131131
if (!mp_obj_get_int_maybe(rhs, &n)) {
132132
return MP_OBJ_NULL; // op not supported
133133
}
134+
if (n < 0) {
135+
n = 0;
136+
}
134137
mp_obj_list_t *s = list_new(o->len * n);
135138
mp_seq_multiply(o->items, sizeof(*o->items), o->len, n, s->items);
136139
return s;

‎py/objstr.c‎

Lines changed: 8 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -290,10 +290,16 @@ mp_obj_t mp_obj_str_binary_op(int op, mp_obj_t lhs_in, mp_obj_t rhs_in) {
290290
break;
291291

292292
case MP_BINARY_OP_MULTIPLY: {
293-
if (!MP_OBJ_IS_SMALL_INT(rhs_in)) {
293+
mp_int_t n;
294+
if (!mp_obj_get_int_maybe(rhs_in, &n)) {
294295
return MP_OBJ_NULL; // op not supported
295296
}
296-
int n = MP_OBJ_SMALL_INT_VALUE(rhs_in);
297+
if (n <= 0) {
298+
if (lhs_type == &mp_type_str) {
299+
return MP_OBJ_NEW_QSTR(MP_QSTR_); // empty str
300+
}
301+
n = 0;
302+
}
297303
byte *data;
298304
mp_obj_t s = mp_obj_str_builder_start(lhs_type, lhs_len * n, &data);
299305
mp_seq_multiply(lhs_data, sizeof(*lhs_data), lhs_len, n, data);

‎py/objtuple.c‎

Lines changed: 5 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -137,10 +137,13 @@ mp_obj_t mp_obj_tuple_binary_op(int op, mp_obj_t lhs, mp_obj_t rhs) {
137137
return s;
138138
}
139139
case MP_BINARY_OP_MULTIPLY: {
140-
if (!MP_OBJ_IS_SMALL_INT(rhs)) {
140+
mp_int_t n;
141+
if (!mp_obj_get_int_maybe(rhs, &n)) {
141142
return MP_OBJ_NULL; // op not supported
142143
}
143-
int n = MP_OBJ_SMALL_INT_VALUE(rhs);
144+
if (n <= 0) {
145+
return mp_const_empty_tuple;
146+
}
144147
mp_obj_tuple_t *s = mp_obj_new_tuple(o->len * n, NULL);
145148
mp_seq_multiply(o->items, sizeof(*o->items), o->len, n, s->items);
146149
return s;

‎tests/basics/bytes_mult.py‎

Lines changed: 12 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,12 @@
1+
# basic multiplication
2+
print(b'0' * 5)
3+
4+
# check negative, 0, positive; lhs and rhs multiplication
5+
for i in (-4, -2, 0, 2, 4):
6+
print(i * b'12')
7+
print(b'12' * i)
8+
9+
# check that we don't modify existing object
10+
a = b'123'
11+
c = a * 3
12+
print(a, c)

‎tests/basics/list_mult.py‎

Lines changed: 9 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,12 @@
1+
# basic multiplication
12
print([0] * 5)
3+
4+
# check negative, 0, positive; lhs and rhs multiplication
5+
for i in (-4, -2, 0, 2, 4):
6+
print(i * [1, 2])
7+
print([1, 2] * i)
8+
9+
# check that we don't modify existing list
210
a = [1, 2, 3]
311
c = a * 3
4-
print(c)
12+
print(a, c)

‎tests/basics/string_mult.py‎

Lines changed: 12 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,12 @@
1+
# basic multiplication
2+
print('0' * 5)
3+
4+
# check negative, 0, positive; lhs and rhs multiplication
5+
for i in (-4, -2, 0, 2, 4):
6+
print(i * '12')
7+
print('12' * i)
8+
9+
# check that we don't modify existing object
10+
a = '123'
11+
c = a * 3
12+
print(a, c)

‎tests/basics/tuple_mult.py‎

Lines changed: 9 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,12 @@
1+
# basic multiplication
12
print((0,) * 5)
3+
4+
# check negative, 0, positive; lhs and rhs multiplication
5+
for i in (-4, -2, 0, 2, 4):
6+
print(i * (1, 2))
7+
print((1, 2) * i)
8+
9+
# check that we don't modify existing tuple
210
a = (1, 2, 3)
311
c = a * 3
4-
print(c)
12+
print(a, c)

0 commit comments

Comments
 (0)