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    // Translated from C to Rust. The original C code can be found at
    // https://github.com/ulfjack/ryu and carries the following license:
    //
    // Copyright 2018 Ulf Adams
    //
    // The contents of this file may be used under the terms of the Apache License,
    // Version 2.0.
    //
    //    (See accompanying file LICENSE-Apache or copy at
    //     http://www.apache.org/licenses/LICENSE-2.0)
    //
    // Alternatively, the contents of this file may be used under the terms of
    // the Boost Software License, Version 1.0.
    //    (See accompanying file LICENSE-Boost or copy at
    //     https://www.boost.org/LICENSE_1_0.txt)
    //
    // Unless required by applicable law or agreed to in writing, this software
    // is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    // KIND, either express or implied.

    use crate::d2s;

    pub const FLOAT_POW5_INV_BITCOUNT: i32 = d2s::DOUBLE_POW5_INV_BITCOUNT - 64;
    pub const FLOAT_POW5_BITCOUNT: i32 = d2s::DOUBLE_POW5_BITCOUNT - 64;

    #[cfg_attr(feature = "no-panic", inline)]
    fn pow5factor_32(mut value: u32) -> u32 {
        let mut count = 0u32;
        loop {
            debug_assert!(value != 0);
            let q = value / 5;
            let r = value % 5;
            if r != 0 {
                break;
            }
            value = q;
            count += 1;
        }
        count
    }

    // Returns true if value is divisible by 5^p.
    #[cfg_attr(feature = "no-panic", inline)]
    pub fn multiple_of_power_of_5_32(value: u32, p: u32) -> bool {
        pow5factor_32(value) >= p
    }

    // Returns true if value is divisible by 2^p.
    #[cfg_attr(feature = "no-panic", inline)]
    pub fn multiple_of_power_of_2_32(value: u32, p: u32) -> bool {
        // __builtin_ctz doesn't appear to be faster here.
        (value & ((1u32 << p) - 1)) == 0
    }

    // It seems to be slightly faster to avoid uint128_t here, although the
    // generated code for uint128_t looks slightly nicer.
    #[cfg_attr(feature = "no-panic", inline)]
    fn mul_shift_32(m: u32, factor: u64, shift: i32) -> u32 {
        debug_assert!(shift > 32);

        // The casts here help MSVC to avoid calls to the __allmul library
        // function.
        let factor_lo = factor as u32;
        let factor_hi = (factor >> 32) as u32;
        let bits0 = m as u64 * factor_lo as u64;
        let bits1 = m as u64 * factor_hi as u64;

        let sum = (bits0 >> 32) + bits1;
        let shifted_sum = sum >> (shift - 32);
        debug_assert!(shifted_sum <= u32::max_value() as u64);
        shifted_sum as u32
    }

    #[cfg_attr(feature = "no-panic", inline)]
    pub fn mul_pow5_inv_div_pow2(m: u32, q: u32, j: i32) -> u32 {
        #[cfg(feature = "small")]
        {
            // The inverse multipliers are defined as [2^x / 5^y] + 1; the upper 64
            // bits from the double lookup table are the correct bits for [2^x /
            // 5^y], so we have to add 1 here. Note that we rely on the fact that
            // the added 1 that's already stored in the table never overflows into
            // the upper 64 bits.
            let pow5 = unsafe { d2s::compute_inv_pow5(q) };
            mul_shift_32(m, pow5.1 + 1, j)
        }

        #[cfg(not(feature = "small"))]
        {
            debug_assert!(q < d2s::DOUBLE_POW5_INV_SPLIT.len() as u32);
            unsafe {
                mul_shift_32(
                    m,
                    d2s::DOUBLE_POW5_INV_SPLIT.get_unchecked(q as usize).1 + 1,
                    j,
                )
            }
        }
    }

    #[cfg_attr(feature = "no-panic", inline)]
    pub fn mul_pow5_div_pow2(m: u32, i: u32, j: i32) -> u32 {
        #[cfg(feature = "small")]
        {
            let pow5 = unsafe { d2s::compute_pow5(i) };
            mul_shift_32(m, pow5.1, j)
        }

        #[cfg(not(feature = "small"))]
        {
            debug_assert!(i < d2s::DOUBLE_POW5_SPLIT.len() as u32);
            unsafe { mul_shift_32(m, d2s::DOUBLE_POW5_SPLIT.get_unchecked(i as usize).1, j) }
        }
    }