foo.cpp

void pretty_print_extensions(std::vector<std::string> &extensions)
{
	// derived from the extension pretty printing from StepMania.
	using namespace std;

	sort( extensions.begin(), extensions.end() );
	size_t next = 0;
	while( next < extensions.size() )
	{
		size_t last = next;
		string type;
		for( size_t i = next; i<extensions.size(); ++i )
		{
			vector<string> segments;
			split(extensions[i], '_', segments);
			string this_type;
			if (segments.size() > 2)
				this_type = join("_", segments.begin(), segments.begin()+2);
			if (i > next && this_type != type)
				break;
			type = this_type;
			last = i;
		}

		if (next == last)
		{
			printf( "  %s\n", extensions[next].c_str() );
			++next;
			continue;
		}

		string sList = ssprintf( "  %s: ", type.c_str() );
		while( next <= last )
		{
			vector<string> segments;
			split( extensions[next], '_', segments );
			string ext_short = join( "_", segments.begin()+2, segments.end() );
			sList += ext_short;
			if (next < last)
				sList += ", ";
			if (next == last || sList.size() + extensions[next+1].size() > 78)
			{
				printf( "%s\n", sList.c_str() );
				sList = "    ";
			}
			++next;
		}
	}
}