Update: use *_size_increase() functions, improve logic, and return F_string_too_large.

Update: use *_size_increase() functions, improve logic, and return F_string_too_large.

Use the *_size_increase() functions more.

Anything declared inside of a loop is destroyed at the end of the loop and created at the beginning.
This is an easily avoidable performance concern.

When the max size is reached but allocation is still possible (but at a smaller than requested length) return F_string_too_large without the error bit set.
This is useful for when only 1 unit is needed but the resize is say 4.
In the cases where the resize must exactly match the given length, then treat F_string_too_large without the error bit as if it does have an error bit.