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objlist: Implement non-growing slice assignment.

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Slice value to assign can be only a list so far too.
This commit is contained in:
Paul Sokolovsky 2014-05-10 22:23:00 +03:00
parent d915a52eb6
commit 94d8246272
3 changed files with 52 additions and 0 deletions
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5
py/obj.h
View File

@ -573,3 +573,8 @@ mp_obj_t mp_seq_index_obj(const mp_obj_t *items, uint len, uint n_args, const mp
mp_obj_t mp_seq_count_obj(const mp_obj_t *items, uint len, mp_obj_t value);
// Helper to clear stale pointers from allocated, but unused memory, to preclude GC problems
#define mp_seq_clear(start, len, alloc_len, item_sz) memset((byte*)(start) + (len) * (item_sz), 0, ((alloc_len) - (len)) * (item_sz))
#define mp_seq_replace_slice_no_grow(dest, dest_len, beg, end, slice, slice_len, item_t) \
/*printf("memcpy(%p, %p, %d)\n", dest + beg, slice, slice_len * sizeof(item_t));*/ \
memcpy(dest + beg, slice, slice_len * sizeof(item_t)); \
/*printf("memcpy(%p, %p, %d)\n", dest + (beg + slice_len), dest + end, (dest_len - end) * sizeof(item_t));*/ \
memcpy(dest + (beg + slice_len), dest + end, (dest_len - end) * sizeof(item_t));

20
py/objlist.c
View File

@ -173,6 +173,26 @@ STATIC mp_obj_t list_subscr(mp_obj_t self_in, mp_obj_t index, mp_obj_t value) {
uint index_val = mp_get_index(self->base.type, self->len, index, false);
return self->items[index_val];
} else {
#if MICROPY_ENABLE_SLICE
if (MP_OBJ_IS_TYPE(index, &mp_type_slice)) {
mp_obj_list_t *self = self_in;
assert(MP_OBJ_IS_TYPE(value, &mp_type_list));
mp_obj_list_t *slice = value;
machine_uint_t start, stop;
if (!mp_seq_get_fast_slice_indexes(self->len, index, &start, &stop)) {
assert(0);
}
int len_adj = slice->len - (stop - start);
//printf("Len adj: %d\n", len_adj);
assert(len_adj <= 0);
mp_seq_replace_slice_no_grow(self->items, self->len, start, stop, slice->items, slice->len, mp_obj_t);
// Clear "freed" elements at the end of list
mp_seq_clear(self->items, self->len + len_adj, self->len, sizeof(*self->items));
self->len += len_adj;
// TODO: apply allocation policy re: alloc_size
return mp_const_none;
}
#endif
mp_obj_list_store(self_in, index, value);
return mp_const_none;
}

27
tests/basics/list_slice_assign.py Normal file
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@ -0,0 +1,27 @@
# test slices; only 2 argument version supported by Micro Python at the moment
x = list(range(10))
# Assignment
l = list(x)
l[1:3] = [10, 20]
print(l)
l = list(x)
l[1:3] = [10]
print(l)
l = list(x)
l[1:3] = []
print(l)
l = list(x)
l[:3] = [10, 20]
print(l)
l = list(x)
l[:3] = []
print(l)
l = list(x)
l[:-3] = [10, 20]
print(l)
l = list(x)
l[:-3] = []
print(l)