//! Formats numbers in hexadecimal, octal, or binary
mod math;

fn as_digit(n: u32) -> char {
    (if n > 9 {
        n - 10 + ('a' as u32)
    } else {
        n + ('0' as u32)
    }) as char
}

pub fn radix(n: i64, radix: i64) {
    fn r_str_radix(n: i64, radix: i64) {
        if n != 0 {
            r_str_radix(n / radix, radix) + as_digit(n % radix)
        } else ""
    }
    if n == 0 {
        "0"
    } else if n < 0 {
        // TODO: breaks at i64::MIN
        "-" + r_str_radix(-n, radix)
    } else r_str_radix(n, radix)
}

pub fn hex(n: u64) {
    let out = "0x";
    for xd in min(count_leading_zeroes(n) / 4, 15)..16 {
        out += as_digit((n >> (15 - xd) * 4) & 0xf)
    }
    out
}
pub fn oct(n: u64) {
    let out = "0o";
    for xd in min((count_leading_zeroes(n) + 2) / 3, 21)..22 {
        out += as_digit((n >> max(63 - (3 * xd), 0)) & 7)
    }
    out
}

pub fn bin(n: u64) {
    let out = "0b";
    for xd in min(count_leading_zeroes(n), 63)..64 {
        out += as_digit((n >> 63 - xd) & 1)
    }
    out
}