ordered_string 0.1.0

Convert integer / float / decimal to string and preserve the order
Documentation 
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pub fn i128_to_ordered_string(value: i128) -> String {
    if value < 0 {
        let offset = (i128::MAX as u128)
            .wrapping_add(1)
            .wrapping_add(value as u128);
        format!("0{:0>39}", offset)
    } else {
        format!("1{:0>39}", value)
    }
}

pub fn f64_to_ordered_string(value: f64) -> String {
    if value.is_nan() {
        panic!("NaN value");
    }

    if value == f64::INFINITY {
        return "2".to_string();
    }
    if value == f64::NEG_INFINITY {
        return "0".to_string();
    }

    let bits = value.to_bits();

    if value < 0.0 {
        let flipped_bits = !bits;
        format!("1{:0>16x}", flipped_bits)
    } else {
        let modified_bits = bits ^ 0x8000000000000000;
        format!("1{:0>16x}", modified_bits)
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_i128_to_ordered_string() {
        let items = vec![
            i128_to_ordered_string(i128::MIN),
            i128_to_ordered_string(-11),
            i128_to_ordered_string(-2),
            i128_to_ordered_string(-1),
            i128_to_ordered_string(0),
            i128_to_ordered_string(1),
            i128_to_ordered_string(2),
            i128_to_ordered_string(11),
            i128_to_ordered_string(111),
            i128_to_ordered_string(i128::MAX),
        ];
        println!("{:#?}", items);
        assert!(items.is_sorted());
    }

    #[test]
    fn test_f64_to_ordered_string() {
        let items = vec![
            f64_to_ordered_string(f64::NEG_INFINITY),
            f64_to_ordered_string(f64::MIN),
            f64_to_ordered_string(-11.11),
            f64_to_ordered_string(-11.1),
            f64_to_ordered_string(-2.0),
            f64_to_ordered_string(-1.0),
            f64_to_ordered_string(0.0),
            f64_to_ordered_string(1.0),
            f64_to_ordered_string(2.0),
            f64_to_ordered_string(11.1),
            f64_to_ordered_string(11.11),
            f64_to_ordered_string(f64::MAX),
            f64_to_ordered_string(f64::INFINITY),
        ];
        println!("{:#?}", items);
        assert!(items.is_sorted());
    }
}