Function resolve_start_from

datafusion/functions-nested/src/position.rs:203–219

Resolves the optional `start_from` argument into a `Vec ` of 0-indexed starting positions.

(
    third_arg: Option<&ColumnarValue>,
    num_rows: usize,
)

/// Resolves the optional `start_from` argument into a `Vec<i64>` of
/// 0-indexed starting positions.
fn resolve_start_from(
    third_arg: Option<&ColumnarValue>,
    num_rows: usize,
) -> Result<Vec<i64>> {
    match third_arg {
        None => Ok(vec![0i64; num_rows]),
        Some(ColumnarValue::Scalar(ScalarValue::Int64(Some(v)))) => {
            Ok(vec![v - 1; num_rows])
        }
        Some(ColumnarValue::Scalar(s)) => {
            exec_err!("array_position expected Int64 for start_from, got {s}")
        }
        Some(ColumnarValue::Array(a)) => {
            Ok(as_int64_array(a)?.values().iter().map(|&x| x - 1).collect())
        }
    }
}

/// Fast path for `array_position` when the needle is scalar.
///