Re: [boost] Any interest in bitstream class?

Subject: Re: [boost] Any interest in bitstream class?
From: Paul Long (plong_at_[hidden])
Date: 2013-06-28 19:18:56

On 6/28/2013 3:32 PM, Mathias Gaunard wrote:
> - how do you overload operator>> or operator<< for your stream?
I'm not sure what you mean by "how." To date, I have only implemented 
the input side and so haven't overloaded operator<<. For operator>>, I 
have overloaded it for various right-hand parameters, including 
integrals and a few stream manipulators, such as aligng(). The left hand 
is always an ibitstream reference (which will be extended to bitstream 
and obitstream references once I support output streams).
> How do you avoid conflicts with text-based overloads?
Maybe I misunderstand your question, but I'm not even aware of how there 
can be a conflict. Since these operators are overloaded with left hand 
of bitstream, ibitstream, or obitstream, they cannot be applied to the 
std::iostream derivatives. Is that what you mean?
> - what does writing an int to a stream actually do? Is it the same 
> behaviour as write(&i, sizeof(int)), or does it translate the int to 
> big-endian first?
Effectively the latter. It does not assume any particular endianness of 
the platform (for example, it does not blindly copy platform memory to 
the bit stream) and therefore does not actually "translate" between 
endians. The effect, however, is that integrals in the bit stream are 
always big endian and integrals on the platform are always their native 
endian. That said, awareness of platform endianness could inform future 
optimizations.

Paul