Re: [boost] [iostreams] binary memory stream

Subject: Re: [boost] [iostreams] binary memory stream
From: Kenny Riddile (kfriddile_at_[hidden])
Date: 2009-03-29 21:10:19

Kenny Riddile wrote:
> I'm still pretty inexperienced with the iostreams library, so this may 
> be a simple question.  I'm trying to use GIL to write a PNG to a memory 
> stream instead of a file stream.  The write_view() function in the new 
> version of GIL's io extension expects an ostream opened in binary mode 
> as it's first parameter, such as:
> 
> using namespace std;
> using namespace boost::gil;
> 
> ofstream outputStream( "foo.png", ios::out | ios::binary );
> write_view( outputStream, const_view(image), png_tag() );
> 
> I'm attempting to write to memory instead of a file, by doing this:
> 
> using namespace boost::gil;
> using namespace boost::iostreams;
> 
> typedef stream< back_insert_device< std::vector<char> > > BufferStream;
> 
> std::vector<char> buffer;
> BufferStream bufferStream( buffer );
> 
> write_view( bufferStream, const_view(image), png_tag() );
> 
> The data that ends up in buffer is identical to the data that ends up in 
> foo.png from the first example if I don't open outputStream in binary 
> mode.  So how can I make a binary memory stream with the iostreams 
> library?  Do I need to write my own filter?
> 
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Ok, so redefining bufferStream like so works:

std::stringstream bufferStream( std::ios_base::in | std::ios_base::out | 
std::ios_base::binary );

but it just feels "weird".  Is there any cleaner way to do this with the 
iostreams library?