<point id="anchor" x="0" y="2" z="0" />
point3 pos(
atof(xPoint->Attribute("x")),
atof(xPoint->Attribute("y")),
atof(xPoint->Attribute("z"))
);
to
<point id="anchor" position="0,1,2" />
and the necessary processing to vector3"0,1,2" to vector3(0,1,2)
Author
How can I turn a string representation of a vector into three doubles to pass to that vector?
Context is getting a vector from an XML attribute, as opposed to three seperate attributes:
Slightly confused - you've got the 2nd of the two options right? position="0,1,2"? Allow me to post the overkill version using boost::spirit
Overkill, but I love boost :-). It'll even accept spaces in that input.
#include <boost/spirit.hpp>using namespace boost;using namespace boost::spirit;struct vector3d{ double x,y,z;};bool parse_vector3d( char const * str , vector3d & vector ){ return parse(str, // Begin grammar ( real_p[assign_a(vector.x)] >> ',' >> real_p[assign_a(vector.y)] >> ',' >> real_p[assign_a(vector.z)] ) , // End grammar space_p).full;}if ( ! parse_vector3d( "0,1,2" , my_vector3d ) ) throw bad_ju_ju;Overkill, but I love boost :-). It'll even accept spaces in that input.
#include <sstream>#include <string>point3 createFromString(const string& pos) { stringstream ss(pos); double x,y,z; char comma; // we won't do any real validation... ss >> x >> comma >> y >> comma >> z; return point3(x,y,z);}point3 pos = createFromString(xPoint->Attribute("position"));Alternatively, you could make the function be a point3 constructor, or static (factory) method.
Author
@MaulingMonkey: What's the performance of that like? Obviously it is at load-time so it's constant and doesn't really matter, but it could be useful in other situations too.
I don't know boost specifically, but my parser is O(n) for n characters - it's an expensive compile time operation to build all the necessary tables though.
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