Re: [Boost-users] max value by the number of bits

Subject: Re: [Boost-users] max value by the number of bits
From: TONGARI (tongari95_at_[hidden])
Date: 2013-02-04 22:03:12

2013/2/5 Christian Henning <chhenning_at_[hidden]>

> Hi there,
>
> is there a general template for calculating the max value by the
> number of bits. GIL right now uses the following template:
>
> template <int K>
> struct unsigned_integral_max_value<packed_channel_value<K> >
>     : public mpl::integral_c<typename
> packed_channel_value<K>::integer_t, (1<<K)-1> {};
>
> This code gives me some compiler errors with clang 3.2. for K = 31,
> for instance. Ideally I would like to take K up to 64.
>
> A small fix gets me up to K = 63
>
> template <int K>
> struct unsigned_integral_max_value<packed_channel_value<K> >
>     : public mpl::integral_c<typename
> packed_channel_value<K>::integer_t, (uint64_t(1)<<K)-1> {};
>
>
> Is there a better way in boost?
>

Try boost::low_bits_mask_t
http://tinyurl.com/bcy22xf

HTH