posts: gap-buffer: add growth

This commit is contained in:
Bruno BELANYI 2024-07-06 23:36:20 +01:00
parent 4d69be0633
commit 0084c8717a

View file

@ -99,3 +99,25 @@ def prefix_length(self) -> int:
def suffix_length(self) -> int:
return self.capacity - self._gap_end
```
### Growing the buffer
I've written this method in a somewhat non-idiomatic manner, to make it closer
to how it would look in C using `realloc` instead.
It would be more efficient to use slicing to insert the needed extra capacity
directly, instead of making a new buffer and copying characters over.
```python
def grow(self, capacity: int) -> None:
assert capacity >= self.capacity
# Create a new buffer with the new capacity
new_buf = [""] * capacity
# Move the prefix/suffix to their place in the new buffer
added_capacity = capacity - len(self._buf)
new_buf[: self._gap_start] = self._buf[: self._gap_start]
new_buf[self._gap_end + added_capacity :] = self._buf[self._gap_end :]
# Use the new buffer, account for added capacity
self._buf = new_buf
self._gap_end += added_capacity
```