Commit 9b7a8ee8 authored by Damien George's avatar Damien George
Browse files

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 #799

Also added ability to mult bytes on LHS by integer.
parent 9d02780e
......@@ -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_
// true acts as 0
return mp_binary_op(op, lhs_in, MP_OBJ_NEW_SMALL_INT(1));
} else if (op == MP_BINARY_OP_MULTIPLY) {
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)) {
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)) {
// multiply is commutative for these types, so delegate to them
return mp_binary_op(op, rhs_in, lhs_in);
}
......
......@@ -131,6 +131,9 @@ STATIC mp_obj_t list_binary_op(int op, mp_obj_t lhs, mp_obj_t rhs) {
if (!mp_obj_get_int_maybe(rhs, &n)) {
return MP_OBJ_NULL; // op not supported
}
if (n < 0) {
n = 0;
}
mp_obj_list_t *s = list_new(o->len * n);
mp_seq_multiply(o->items, sizeof(*o->items), o->len, n, s->items);
return s;
......
......@@ -290,10 +290,16 @@ mp_obj_t mp_obj_str_binary_op(int op, mp_obj_t lhs_in, mp_obj_t rhs_in) {
break;
case MP_BINARY_OP_MULTIPLY: {
if (!MP_OBJ_IS_SMALL_INT(rhs_in)) {
mp_int_t n;
if (!mp_obj_get_int_maybe(rhs_in, &n)) {
return MP_OBJ_NULL; // op not supported
}
int n = MP_OBJ_SMALL_INT_VALUE(rhs_in);
if (n <= 0) {
if (lhs_type == &mp_type_str) {
return MP_OBJ_NEW_QSTR(MP_QSTR_); // empty str
}
n = 0;
}
byte *data;
mp_obj_t s = mp_obj_str_builder_start(lhs_type, lhs_len * n, &data);
mp_seq_multiply(lhs_data, sizeof(*lhs_data), lhs_len, n, data);
......
......@@ -137,10 +137,13 @@ mp_obj_t mp_obj_tuple_binary_op(int op, mp_obj_t lhs, mp_obj_t rhs) {
return s;
}
case MP_BINARY_OP_MULTIPLY: {
if (!MP_OBJ_IS_SMALL_INT(rhs)) {
mp_int_t n;
if (!mp_obj_get_int_maybe(rhs, &n)) {
return MP_OBJ_NULL; // op not supported
}
int n = MP_OBJ_SMALL_INT_VALUE(rhs);
if (n <= 0) {
return mp_const_empty_tuple;
}
mp_obj_tuple_t *s = mp_obj_new_tuple(o->len * n, NULL);
mp_seq_multiply(o->items, sizeof(*o->items), o->len, n, s->items);
return s;
......
# basic multiplication
print(b'0' * 5)
# check negative, 0, positive; lhs and rhs multiplication
for i in (-4, -2, 0, 2, 4):
print(i * b'12')
print(b'12' * i)
# check that we don't modify existing object
a = b'123'
c = a * 3
print(a, c)
# basic multiplication
print([0] * 5)
# check negative, 0, positive; lhs and rhs multiplication
for i in (-4, -2, 0, 2, 4):
print(i * [1, 2])
print([1, 2] * i)
# check that we don't modify existing list
a = [1, 2, 3]
c = a * 3
print(c)
print(a, c)
# basic multiplication
print('0' * 5)
# check negative, 0, positive; lhs and rhs multiplication
for i in (-4, -2, 0, 2, 4):
print(i * '12')
print('12' * i)
# check that we don't modify existing object
a = '123'
c = a * 3
print(a, c)
# basic multiplication
print((0,) * 5)
# check negative, 0, positive; lhs and rhs multiplication
for i in (-4, -2, 0, 2, 4):
print(i * (1, 2))
print((1, 2) * i)
# check that we don't modify existing tuple
a = (1, 2, 3)
c = a * 3
print(c)
print(a, c)
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