reading out a stringstream and insert it in different vectores - c++

Question

(I'm sorry if I ask this question wrong, this is my first time I write in a forum)
When I started programming at my SFML - Game, I had a very old book, wich was very C-like (eg. recommendation of atoi();).
Now I got a new C++(including C++11) book, and I want to rewrite the old lines wih newer Code.
I saved the Tiles in a file stored like this:
[0-0,15-1|22,44] [0-1|0]
[4-0,10-1,3-1|0] [0-5,5-5|0]
That means:
[...] desribes a Tile
0-0 etc. is the xy position on the Texturesheet
22 etc. is the event that will be triggered.
the amount of events and sf::Vector2i shouldn't be set constantly.
The Tiles are separately taken out from another class, which manages the entire Tilemap.
Now my problem: I have no idea how i should push the numbers from the strinstream right in two vectores?
My code:
class Tile{
private:
std::deque<sf::Sprite> tile;
std::deque<int> event;
public:
Tile(sf::Texture& texture, std::deque<sf::Vector2i>&& ctor_texturerects, std::deque<int>&& ctor_events);//This one is working fine
Tile(sf::Texture& texture, std::stringstream&& ctor_stream/*reads the Tile*/){
std::deque<sf::Vector2i> temp_texturerects;
std::deque<int>temp_events;
/*TODO: filter the stringstream and push them into the containers*/
Tile::Tile(texture,std::move(temp_texturerect),std::move(temp_events));
}
I'd be also very happy if you could give me another solution, like changing sf::Vector2i to a better solution or giving me a better stream and class concept
Thanks in advance
Xeno Ceph
Edit:
I made a little workaround:
(I changed the inputstream to a normal string)
But the code doesn't look good
There mujst be an easier solution
Tile:: Tile(sf::Texture& texture, std::string&& ctor_string){
std::deque<sf::Vector2i> temp_texturerects;
std::deque<int> temp_events;
std::stringstream strstr;
for(int i=0; i<ctor_string.size(); ++i){
while(ctor_string[i]!='|'){
while(ctor_string[i] != ','){
strstr << ctor_string[i];
}
sf::Vector2i v2i;
strstr >> v2i.x >> v2i.y;
temp_texturerects.push_front(v2i);
strstr.str("");
}
while(ctor_string[i]!=']'){
while(ctor_string[i] != ','){
strstr << ctor_string[i];
}
int integer;
strstr >> integer;
temp_events.push_front(integer);
strstr.str("");
}
}
Tile::Tile(texture, std::move(temp_texturerects), std::move(temp_events));
}
Has anybody a better solution?

Answer 1

If I understand your question correctly, you have some strings of the form
[0-0,15-1|22,44] [0-1|0]
[4-0,10-1,3-1|0] [0-5,5-5|0]
and you want to extract 2 types of data - positions (e.g. 0-0) and events (e.g. 22).
Your question is how to extract this data cleanly, discarding the [ and ] characters, etc.
One great way to approach this is to use the getline function that operates on stringstreams, which inherit from std::istream (http://www.cplusplus.com/reference/string/string/getline/). It can take custom delimiters, not just the newline character. So you can use '[', '|' and ']' as different delimiting characters and parse them in a logical order.
For example, since your string is just a collection of tiles, you can split it up into a number of functions - ParseTile, ParsePositions and ParseEvents, something like the following:
void Tile::ParseInput(stringstream&& ctor_string) {
//extract input, tile by tile
while(!ctor_string.eof()) {
string tile;
//you can treat each tile as though it is on a separate line by
//specifying the ']' character as the delimiter for the "line"
getline(ctor_string, tile, ']');
tile += "]"; //add back the ']' character that was discarded from the getline
//the string "tile" should now contain a single tile [...], which we can further process using ParseTile
ParseTile(tile);
}
}
The ParseTile function:
void Tile::ParseTile(string&& tile) {
//input string tile is e.g. " [0-0, 15-1|22,44]"
string discard; //string to hold parts of tile string that should be thrown away
string positions; //string to hold list of positions, separated by ','
string events; //string to hold events, separated by ','
//create stringstream from input
stringstream tilestream(tile);
//tilestream is e.g. "[0-0,15-1|22,44]"
getline(tilestream, discard, '['); //gets everything until '['
//now, discard is " [" and tilestream is "0-0,15-1|22,44]"
getline(tilestream, positions, '|');
//now, positions is "0-0,15-1" and tilestream is "22,44]"
getline(tilestream, events,']');
//now, events is "22,44" and tilestream is empty
ParsePositions(positions);
ParseEvents(events);
}
You can write your own ParsePositions and ParseEvents functions which basically will be a more getline calls using a ',' as the delimiting character (just loop until the string ends).

Answer 2

I suggest either writing a proper parser manually (not unlike the other answer proposes) or to use a proper parsing framework, like Boost Spirit.
The advantages of the latter is that you get debuggability, composability, attributes etc. "for free". Here's the simplest example I could think of:
struct TileData
{
std::deque<sf::Vector2i> texturerects;
std::deque<int> events;
};
typedef std::deque<TileData> TileDatas;
template <typename It>
struct parser : qi::grammar<It, TileDatas(), qi::space_type>
{
parser() : parser::base_type(start)
{
using namespace qi;
v2i = (int_ >> '-' >> int_)
[ _val = phx::construct<sf::Vector2i>(_1, _2) ];
tiledata =
(v2i % ',') >> '|' >>
(int_ % ',');
start = *('[' >> tiledata >> ']');
}
private:
qi::rule<It, sf::Vector2i(), qi::space_type> v2i;
qi::rule<It, TileData(), qi::space_type> tiledata;
qi::rule<It, TileDatas(), qi::space_type> start;
};
Adding a bit of code to test this, see it live on http://liveworkspace.org/code/3WM0My$1, output:
Parsed: TileData {
texturerects: deque<N2sf8Vector2iE> {v2i(0, 0), v2i(15, 1), }
events: deque<i> {22, 44, }
}
Parsed: TileData {
texturerects: deque<N2sf8Vector2iE> {v2i(0, 1), }
events: deque<i> {0, }
}
Parsed: TileData {
texturerects: deque<N2sf8Vector2iE> {v2i(4, 0), v2i(10, 1), v2i(3, 1), }
events: deque<i> {0, }
}
Parsed: TileData {
texturerects: deque<N2sf8Vector2iE> {v2i(0, 5), v2i(5, 5), }
events: deque<i> {0, }
}
Full code:
#define BOOST_SPIRIT_USE_PHOENIX_V3
// #define BOOST_SPIRIT_DEBUG
#include <boost/fusion/adapted/struct.hpp>
#include <boost/spirit/include/support_istream_iterator.hpp>
#include <boost/spirit/include/qi.hpp>
#include <boost/spirit/include/phoenix.hpp>
namespace qi = boost::spirit::qi;
namespace phx= boost::phoenix;
// liveworkspace.org doesn't have SFML
namespace sf { struct Vector2i { int x, y; Vector2i(int ax=0, int ay=0) : x(ax), y(ay) {} }; }
struct TileData
{
std::deque<sf::Vector2i> texturerects;
std::deque<int> events;
};
BOOST_FUSION_ADAPT_STRUCT(TileData,
(std::deque<sf::Vector2i>, texturerects)
(std::deque<int>, events))
typedef std::deque<TileData> TileDatas;
template <typename It>
struct parser : qi::grammar<It, TileDatas(), qi::space_type>
{
parser() : parser::base_type(start)
{
using namespace qi;
v2i = (int_ >> '-' >> int_)
[ _val = phx::construct<sf::Vector2i>(_1, _2) ];
tiledata =
(v2i % ',') >> '|' >>
(int_ % ',');
start = *('[' >> tiledata >> ']');
}
private:
qi::rule<It, sf::Vector2i(), qi::space_type> v2i;
qi::rule<It, TileData(), qi::space_type> tiledata;
qi::rule<It, TileDatas(), qi::space_type> start;
};
typedef boost::spirit::istream_iterator It;
std::ostream& operator<<(std::ostream& os, sf::Vector2i const &v) { return os << "v2i(" << v.x << ", " << v.y << ")"; }
template <typename T> std::ostream& operator<<(std::ostream& os, std::deque<T> const &d) {
os << "deque<" << typeid(T).name() << "> {";
for (auto& t : d) os << t << ", ";
return os << "}";
}
std::ostream& operator<<(std::ostream& os, TileData const& ttd) {
return os << "TileData {\n"
"\ttexturerects: " << ttd.texturerects << "\n"
"\tevents: " << ttd.events << "\n}";
}
int main()
{
parser<It> p;
std::istringstream iss(
"[0-0,15-1|22,44] [0-1|0]\n"
"[4-0,10-1,3-1|0] [0-5,5-5|0]");
It f(iss), l;
TileDatas data;
if (qi::phrase_parse(f,l,p,qi::space,data))
{
for (auto& tile : data)
{
std::cout << "Parsed: " << tile << "\n";
}
}
if (f != l)
{
std::cout << "Remaining unparsed: '" << std::string(f, l) << "'\n";
}
}