Re: [Boost-users] Convert big endian to little endian (floating point values)

On 12/8/2015 11:32 PM, Paolo Bolzoni wrote:

On Wed, Dec 9, 2015 at 7:18 AM, Martin Vymazal wrote:

...

What would be a possible approach to save the data without 'relying on the platform specific bit representation of primitive data types' as you put it?

What about using boost integer to find an unsigned integer (let's call its type Lint) longer or equal than the float (type Float) you have and make an union?

Ugh, this again? Third time this week... just no.

union Lint_Float_t { Lint store; Float read; }; static_assert(sizeof(Lint) >= sizeof(Float), "");

To store you copy the float in the union, and save the integer. To load you load the integer and copy from the union the float.

It is definitely not portable (reading and writing different types in a union is at most implementation dependant) and you keep the original bits, but it should work at least on machine of the same type.

Reading from an inactive member of a union is plain and simply undefined behavior. To read and write the bits of the `float` in a well defined way use `std::memcpy`. Regards, -- Agustín K-ballo Bergé.- http://talesofcpp.fusionfenix.com