I'm trying to create a string I can tokenise, from a file. What works is
boost::iostreams::stream_buffer<boost::iostreams::mapped_file_source> file("file.txt");
boost::char_separator<char> sep(",");
std::string buf(file->begin(),file->end())
boost::tokenizer<boost::char_separator<char>> tokeniser(buf,sep);
But I don't to unnecessarily copy file's buffer to the string I thought I could do:
boost::iostreams::stream_buffer<boost::iostreams::mapped_file_source> file("file.txt");
boost::iterator_range<const char*> it = make_iterator_range(file->begin(),file->end());
boost::tokenizer<boost::char_separator<char>> tokeniser(it,sep);
or
std::istringstream buf;
buf.rdbuf()->pubsetbuf(const_cast<char*>(file->data()),file->size());
boost::char_separator<char> sep(",");
boost::tokenizer<boost::char_separator<char>> tokeniser(buf,sep);
I also tried
boost::tokenizer<boost::char_separator<char>> tokeniser(boost::as_literal(file->data()),sep);
But each time the tokenizer doesn't accept the iterator
Is there an efficient portable way of doing this?
Edit Possible answer I think would solve this
What I have thought of since, is to use an istream iterator to achieve the non-copy as I'm fairly (though not 100%) confident that iterators iterate over and do not copy their underlying data
boost::iostreams::stream_buffer<boost::iostreams::mapped_file_source> file("names.txt");
std::istream in(&file);
std::istream_iterator<std::string> iter(in);
boost::char_separator<char> sep(",");
boost::tokenizer<boost::char_separator<char>> tokeniser(*iter,sep);
Thoughts? Or is there something better?
