Function search_in_slice

datafusion/common/src/utils/mod.rs:221–239

This function searches for a tuple of given values (`target`) among a slice of the given rows (`item_columns`) via a linear scan. The slice starts at the index `low` and ends at the index `high`. The boolean-valued function `compare_fn` specifies the stopping criterion.

(
    item_columns: &[ArrayRef],
    target: &[ScalarValue],
    compare_fn: F,
    mut low: usize,
    high: usize,
)

/// `low` and ends at the index `high`. The boolean-valued function `compare_fn`
/// specifies the stopping criterion.
pub fn search_in_slice<F>(
    item_columns: &[ArrayRef],
    target: &[ScalarValue],
    compare_fn: F,
    mut low: usize,
    high: usize,
) -> Result<usize>
where
    F: Fn(&[ScalarValue], &[ScalarValue]) -> Result<bool>,
{
    while low < high {
        let val = get_row_at_idx(item_columns, low)?;
        if !compare_fn(&val, target)? {
            break;
        }
        low += 1;
    }
    Ok(low)
}

/// Given a list of 0 or more already sorted columns, finds the
/// partition ranges that would partition equally across columns.