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    mod exponent;
    mod mantissa;

    use self::exponent::*;
    use self::mantissa::*;
    use crate::common;
    use crate::d2s::{self, *};
    use crate::f2s::*;
    use core::ptr;
    #[cfg(feature = "no-panic")]
    use no_panic::no_panic;

    /// Print f64 to the given buffer and return number of bytes written.
    ///
    /// At most 24 bytes will be written.
    ///
    /// ## Special cases
    ///
    /// This function **does not** check for NaN or infinity. If the input
    /// number is not a finite float, the printed representation will be some
    /// correctly formatted but unspecified numerical value.
    ///
    /// Please check [`is_finite`] yourself before calling this function, or
    /// check [`is_nan`] and [`is_infinite`] and handle those cases yourself.
    ///
    /// [`is_finite`]: https://doc.rust-lang.org/std/primitive.f64.html#method.is_finite
    /// [`is_nan`]: https://doc.rust-lang.org/std/primitive.f64.html#method.is_nan
    /// [`is_infinite`]: https://doc.rust-lang.org/std/primitive.f64.html#method.is_infinite
    ///
    /// ## Safety
    ///
    /// The `result` pointer argument must point to sufficiently many writable bytes
    /// to hold Ryū's representation of `f`.
    ///
    /// ## Example
    ///
    /// ```
    /// use std::{mem::MaybeUninit, slice, str};
    ///
    /// let f = 1.234f64;
    ///
    /// unsafe {
    ///     let mut buffer = [MaybeUninit::<u8>::uninit(); 24];
    ///     let len = ryu::raw::format64(f, buffer.as_mut_ptr() as *mut u8);
    ///     let slice = slice::from_raw_parts(buffer.as_ptr() as *const u8, len);
    ///     let print = str::from_utf8_unchecked(slice);
    ///     assert_eq!(print, "1.234");
    /// }
    /// ```
    #[must_use]
    #[cfg_attr(feature = "no-panic", no_panic)]
    pub unsafe fn format64(f: f64, result: *mut u8) -> usize {
        let bits = f.to_bits();
        let sign = ((bits >> (DOUBLE_MANTISSA_BITS + DOUBLE_EXPONENT_BITS)) & 1) != 0;
        let ieee_mantissa = bits & ((1u64 << DOUBLE_MANTISSA_BITS) - 1);
        let ieee_exponent =
            (bits >> DOUBLE_MANTISSA_BITS) as u32 & ((1u32 << DOUBLE_EXPONENT_BITS) - 1);

        let mut index = 0isize;
        if sign {
            *result = b'-';
            index += 1;
        }

        if ieee_exponent == 0 && ieee_mantissa == 0 {
            ptr::copy_nonoverlapping(b"0.0".as_ptr(), result.offset(index), 3);
            return sign as usize + 3;
        }

        let v = d2d(ieee_mantissa, ieee_exponent);

        let length = d2s::decimal_length17(v.mantissa) as isize;
        let k = v.exponent as isize;
        let kk = length + k; // 10^(kk-1) <= v < 10^kk
        debug_assert!(k >= -324);

        if 0 <= k && kk <= 16 {
            // 1234e7 -> 12340000000.0
            write_mantissa_long(v.mantissa, result.offset(index + length));
            for i in length..kk {
                *result.offset(index + i) = b'0';
            }
            *result.offset(index + kk) = b'.';
            *result.offset(index + kk + 1) = b'0';
            index as usize + kk as usize + 2
        } else if 0 < kk && kk <= 16 {
            // 1234e-2 -> 12.34
            write_mantissa_long(v.mantissa, result.offset(index + length + 1));
            ptr::copy(result.offset(index + 1), result.offset(index), kk as usize);
            *result.offset(index + kk) = b'.';
            index as usize + length as usize + 1
        } else if -5 < kk && kk <= 0 {
            // 1234e-6 -> 0.001234
            *result.offset(index) = b'0';
            *result.offset(index + 1) = b'.';
            let offset = 2 - kk;
            for i in 2..offset {
                *result.offset(index + i) = b'0';
            }
            write_mantissa_long(v.mantissa, result.offset(index + length + offset));
            index as usize + length as usize + offset as usize
        } else if length == 1 {
            // 1e30
            *result.offset(index) = b'0' + v.mantissa as u8;
            *result.offset(index + 1) = b'e';
            index as usize + 2 + write_exponent3(kk - 1, result.offset(index + 2))
        } else {
            // 1234e30 -> 1.234e33
            write_mantissa_long(v.mantissa, result.offset(index + length + 1));
            *result.offset(index) = *result.offset(index + 1);
            *result.offset(index + 1) = b'.';
            *result.offset(index + length + 1) = b'e';
            index as usize
                + length as usize
                + 2
                + write_exponent3(kk - 1, result.offset(index + length + 2))
        }
    }

    /// Print f32 to the given buffer and return number of bytes written.
    ///
    /// At most 16 bytes will be written.
    ///
    /// ## Special cases
    ///
    /// This function **does not** check for NaN or infinity. If the input
    /// number is not a finite float, the printed representation will be some
    /// correctly formatted but unspecified numerical value.
    ///
    /// Please check [`is_finite`] yourself before calling this function, or
    /// check [`is_nan`] and [`is_infinite`] and handle those cases yourself.
    ///
    /// [`is_finite`]: https://doc.rust-lang.org/std/primitive.f32.html#method.is_finite
    /// [`is_nan`]: https://doc.rust-lang.org/std/primitive.f32.html#method.is_nan
    /// [`is_infinite`]: https://doc.rust-lang.org/std/primitive.f32.html#method.is_infinite
    ///
    /// ## Safety
    ///
    /// The `result` pointer argument must point to sufficiently many writable bytes
    /// to hold Ryū's representation of `f`.
    ///
    /// ## Example
    ///
    /// ```
    /// use std::{mem::MaybeUninit, slice, str};
    ///
    /// let f = 1.234f32;
    ///
    /// unsafe {
    ///     let mut buffer = [MaybeUninit::<u8>::uninit(); 16];
    ///     let len = ryu::raw::format32(f, buffer.as_mut_ptr() as *mut u8);
    ///     let slice = slice::from_raw_parts(buffer.as_ptr() as *const u8, len);
    ///     let print = str::from_utf8_unchecked(slice);
    ///     assert_eq!(print, "1.234");
    /// }
    /// ```
    #[must_use]
    #[cfg_attr(feature = "no-panic", no_panic)]
    pub unsafe fn format32(f: f32, result: *mut u8) -> usize {
        let bits = f.to_bits();
        let sign = ((bits >> (FLOAT_MANTISSA_BITS + FLOAT_EXPONENT_BITS)) & 1) != 0;
        let ieee_mantissa = bits & ((1u32 << FLOAT_MANTISSA_BITS) - 1);
        let ieee_exponent = (bits >> FLOAT_MANTISSA_BITS) & ((1u32 << FLOAT_EXPONENT_BITS) - 1);

        let mut index = 0isize;
        if sign {
            *result = b'-';
            index += 1;
        }

        if ieee_exponent == 0 && ieee_mantissa == 0 {
            ptr::copy_nonoverlapping(b"0.0".as_ptr(), result.offset(index), 3);
            return sign as usize + 3;
        }

        let v = f2d(ieee_mantissa, ieee_exponent);

        let length = common::decimal_length9(v.mantissa) as isize;
        let k = v.exponent as isize;
        let kk = length + k; // 10^(kk-1) <= v < 10^kk
        debug_assert!(k >= -45);

        if 0 <= k && kk <= 13 {
            // 1234e7 -> 12340000000.0
            write_mantissa(v.mantissa, result.offset(index + length));
            for i in length..kk {
                *result.offset(index + i) = b'0';
            }
            *result.offset(index + kk) = b'.';
            *result.offset(index + kk + 1) = b'0';
            index as usize + kk as usize + 2
        } else if 0 < kk && kk <= 13 {
            // 1234e-2 -> 12.34
            write_mantissa(v.mantissa, result.offset(index + length + 1));
            ptr::copy(result.offset(index + 1), result.offset(index), kk as usize);
            *result.offset(index + kk) = b'.';
            index as usize + length as usize + 1
        } else if -6 < kk && kk <= 0 {
            // 1234e-6 -> 0.001234
            *result.offset(index) = b'0';
            *result.offset(index + 1) = b'.';
            let offset = 2 - kk;
            for i in 2..offset {
                *result.offset(index + i) = b'0';
            }
            write_mantissa(v.mantissa, result.offset(index + length + offset));
            index as usize + length as usize + offset as usize
        } else if length == 1 {
            // 1e30
            *result.offset(index) = b'0' + v.mantissa as u8;
            *result.offset(index + 1) = b'e';
            index as usize + 2 + write_exponent2(kk - 1, result.offset(index + 2))
        } else {
            // 1234e30 -> 1.234e33
            write_mantissa(v.mantissa, result.offset(index + length + 1));
            *result.offset(index) = *result.offset(index + 1);
            *result.offset(index + 1) = b'.';
            *result.offset(index + length + 1) = b'e';
            index as usize
                + length as usize
                + 2
                + write_exponent2(kk - 1, result.offset(index + length + 2))
        }
    }