strong prism
it doesnt have a deint because its just a simple slice not a container. you still need to free it because its still allocated just like the items of an arraylist are it simply transfers ownership out of the arraylist (metaphorically speaking, zig has no concept of ownership)
#Why dont i need to free a owned slice?
neat pond
arraylist if it's expected that the caller might need to add or remove items, slice if not
topaz plinth
the function that returns a slice often takes in an allocator, which in most cases indicates that the slice was allocated and needs to be deinit after done using it
sand pebble
Worth noting that toOwnedSlice might allocate a new buffer and copy elements over. For that reason, if you are looking for absolute best performance it might be better to return the array directly.
Would be nice if we had a DynamicBoundedArray to return instead.
neat pond
how would such a thing work?
vocal sparrow
Worth noting that toOwnedSlice might allocate a new buffer and copy elements ove...
if the arraylist goes out of scope, so does the backing slice
sand pebble
how would such a thing work?
You could return a type is essentially the same as an array list, but cannot use an allocator to grow the capacity
sand pebble
if the arraylist goes out of scope, so does the backing slice
You can return an array list as long as you don't deinit it.
Zig doesn't have destructor , so doesn't need move semantics either
vocal sparrow
im aware
but u said return the array, which sounds to me like u means list.items
which, ig its allocated, so that could be fine
sand pebble
Oh no I meant the array list
sand pebble
which, ig its allocated, so that could be fine
No because you can't free that slice. The array list may have allocated a larger array, which it keeps track of internally.
So you need to return a type that stores a slice + the size of the allocation so it can be freed
vocal sparrow
right that makes sense
i couldnt remember
not at my computer rn to check the impl
sand pebble
Yeah array list is a bit weird in it's impl but it let's you query items.len or iterate over items that way
vocal sparrow
yeah
neat pond
You could return a type is essentially the same as an array list, but cannot us...
is this different than ArrayListUnmanaged?
what's the benefit in (i assume) allowing the caller to free the underlying slice with an allocator, but not to resize it?
sand pebble
No you are right, it's no different
neat pond
as long as you free the returned slice (and free memory owned by each item, if there is any) you're fine
toOwnedSlice leaves the arraylist empty, so calling deinit is safe but unnecessary
sand pebble
ToOwnedSlice may allocate and copy, so yeah it's not free.