Method expand

arrow-buffer/src/buffer/null.rs:116–134

Returns a new [`NullBuffer`] where each bit in the current null buffer is repeated `count` times. This is useful for masking the nulls of the child of a FixedSizeListArray based on its parent

(&self, count: usize)

    /// is repeated `count` times. This is useful for masking the nulls of
    /// the child of a FixedSizeListArray based on its parent
    pub fn expand(&self, count: usize) -> Self {
        let capacity = self.buffer.len().checked_mul(count).unwrap();
        let mut buffer = MutableBuffer::new_null(capacity);

        // Expand each bit within `null_mask` into `element_len`
        // bits, constructing the implicit mask of the child elements
        for i in 0..self.buffer.len() {
            if self.is_null(i) {
                continue;
            }
            for j in 0..count {
                crate::bit_util::set_bit(buffer.as_mut(), i * count + j)
            }
        }
        Self {
            buffer: BooleanBuffer::new(buffer.into(), 0, capacity),
            null_count: self.null_count * count,
        }
    }

    /// Returns the length of this [`NullBuffer`] in bits
    #[inline]