Function pow_decimal256_float_fallback

datafusion/functions/src/math/power.rs:350–370

Fallback implementation for Decimal256.

(
    base: i256,
    scale: i8,
    exp: f64,
)

/// Fallback implementation for Decimal256.
fn pow_decimal256_float_fallback(
    base: i256,
    scale: i8,
    exp: f64,
) -> Result<i256, ArrowError> {
    if scale < 0 {
        return Err(ArrowError::NotYetImplemented(format!(
            "Negative scale is not yet supported: {scale}"
        )));
    }

    let scale_factor = 10f64.powi(scale as i32);
    let base_f64 = base.to_f64().ok_or_else(|| {
        ArrowError::ComputeError("Cannot convert base to f64".to_string())
    })? / scale_factor;

    let result_i128 = compute_pow_f64_result(base_f64, scale, exp)?;

    // i256 can be constructed from i128 directly
    Ok(i256::from_i128(result_i128))
}

/// Fallback implementation for decimal power when exponent is an array.
/// Casts decimal to float64, computes power, and casts back to original decimal type.