cocoa - NSURL: Display Relative URLs? -

has come across solution or addition nsurl make relative file url based on this:

nsurl * = [nsurl urlwithstring:@"/users/me/scripts/python/test.py"]; nsurl * = [nsurl urlwithstring:@"/users/me/new-scripts/python/test.py"]; nsurl * rel = [nsurl urlfrom:from to:to]; nslog(@"%@",rel); --> ../../new-scripts/python/test.py 

and i'm looking able take relative path "../../new-scripts/python/test.py" , combine absolute url new url.

[nsurl urlwithstring:@"../../new-scripts/python/test.py" relativetourl:[nsurl fileurlwithpath:@"/users/me/scripts/python/test.py"]]; 

haven't come across on google, , trying implement myself can end having lot intricacies correctness. wondering if apple or or if c/posix functions exist already?

thanks!

i came accross https://github.com/karelia/ksfileutilities, doesn't work file urls. wrote this. http://pastebin.com/fkyjvwpu

#import <foundation/foundation.h>  nsstring * relativize(nsurl * to, nsurl * from, bool fromisdir);  int main(int argc, const char * argv[]) {      @autoreleasepool {         //nsurl * u = [nsurl urlwithstring:@"../../scripts" relativetourl:[nsurl fileurlwithpath:@"/users/aaronsmith/development/aaron/"]];         //nslog(@"%@",u.absolutestring);         //nslog(@"%@",[nsurl urlwithstring:@"../../scripts.py" relativetourl:[nsurl fileurlwithpath:@"/users/aaronsmith/scipts/"]]);          nsurl * = null;         nsurl * = null;          = [nsurl fileurlwithpath:@"/users/aaronsmith/uverse/upload-issue.py"];         = [nsurl fileurlwithpath:@"/users/aaronsmith/scripts.scrpt"];         assert([relativize(to,from,false) isequaltostring:@"./uverse/upload-issue.py"]);          = [nsurl fileurlwithpath:@"/users/aaronsmith/uverse/test/upload-issue.py"];         = [nsurl fileurlwithpath:@"/users/aaronsmith/"];         assert([relativize(to, from, true) isequaltostring:@"./uverse/test/upload-issue.py"]);         relativize(to,from,true);          = [nsurl fileurlwithpath:@"/users/aaronsmith/uverse/test/upload-issue.py"];         = [nsurl fileurlwithpath:@"/users/aaronsmith/example/scripts/"];         assert([relativize(to,from,true) isequaltostring:@"../../uverse/test/upload-issue.py"]);          = [nsurl fileurlwithpath:@"/users/aaronsmith/uverse/test/scripts/stuff/upload-issue.py"];         = [nsurl fileurlwithpath:@"/users/johnson/scripts/"];         assert([relativize(to,from,true) isequaltostring:@"../../aaronsmith/uverse/test/scripts/stuff/upload-issue.py"]);          = [nsurl urlwithstring:@"/users/aaronsmith/upload-issue.py"];         = [nsurl urlwithstring:@"/users/aaronsmith/"];         assert([relativize(to,from,true) isequaltostring:@"./upload-issue.py"]);          = [nsurl urlwithstring:@"/users/aaronsmith/upload-issue.py"];         = [nsurl urlwithstring:@"/users/aaronsmith/scripts.scrpt"];         assert([relativize(to,from,false) isequaltostring:@"./upload-issue.py"]);          = [nsurl urlwithstring: @"/users/aaronsmith/uverse/test/upload-issue.py"];         = [nsurl urlwithstring:@"/users/aaronsmith/test/whatever/scripts/script.scrpt"];         assert([relativize(to,from,false) isequaltostring:@"../../../uverse/test/upload-issue.py"]);          = [nsurl urlwithstring: @"/users/aaronsmith/uverse/test/upload-issue.py"];         = [nsurl urlwithstring:@"/users/aaronsmith/test/whatever/scripts/"];         assert([relativize(to,from,true) isequaltostring:@"../../../uverse/test/upload-issue.py"]);          = [nsurl urlwithstring:@"/users/aaronsmith/uverse/test/upload-issue.py"];         = [nsurl urlwithstring:@"/users/aaronsmith/uverse/test/scripts.scrpt"];         assert([relativize(to, from, false) isequaltostring:@"./upload-issue.py"]);          = [nsurl urlwithstring:@"/users/aaronsmith/upload-issue.py"];         = [nsurl urlwithstring:@"/users/aaronsmith/uverse/test/scripts.scrpt"];         assert([relativize(to, from, false) isequaltostring:@"../../upload-issue.py"]);     }      return 0; }  nsstring * relativize(nsurl * to, nsurl * from, bool fromisdir) {     nsstring * tostring = [[to absolutestring] stringbystandardizingpath];     nsmutablearray * topieces = [nsmutablearray arraywitharray:[tostring pathcomponents]];      nsstring * fromstring = [[from absolutestring] stringbystandardizingpath];     nsmutablearray * frompieces = [nsmutablearray arraywitharray:[fromstring pathcomponents]];      nsmutablestring * relpath = [nsmutablestring string];      nsstring * totrimmed = tostring;     nsstring * topiece = null;     nsstring * fromtrimmed = fromstring;     nsstring * frompiece = null;      nsmutablearray * parents = [nsmutablearray array];     nsmutablearray * pieces = [nsmutablearray array];      if(topieces.count >= frompieces.count) {         nsuinteger tocount = topieces.count;         while(tocount > frompieces.count) {             topiece = [totrimmed lastpathcomponent];             totrimmed = [totrimmed stringbydeletinglastpathcomponent];             [pieces insertobject:topiece atindex:0];             tocount--;         }          while(![fromtrimmed isequaltostring:totrimmed]) {             topiece = [totrimmed lastpathcomponent];             totrimmed = [totrimmed stringbydeletinglastpathcomponent];             frompiece = [fromtrimmed lastpathcomponent];             fromtrimmed = [fromtrimmed stringbydeletinglastpathcomponent];             if(![topiece isequaltostring:frompiece]) {                 if(![frompiece isequaltostring:[frompiece lastpathcomponent]] || fromisdir) {                     [parents addobject:@".."];                 }                 [pieces insertobject:topiece atindex:0];             }         }      } else {         nsuinteger fromcount = frompieces.count;          while(fromcount > topieces.count) {             frompiece = [fromtrimmed lastpathcomponent];             fromtrimmed = [fromtrimmed stringbydeletinglastpathcomponent];             if(![frompiece isequaltostring:[fromstring lastpathcomponent]] || fromisdir) {                 [parents addobject:@".."];             }             fromcount--;         }          while(![totrimmed isequaltostring:fromtrimmed]) {             topiece = [totrimmed lastpathcomponent];             totrimmed = [totrimmed stringbydeletinglastpathcomponent];             frompiece = [fromtrimmed lastpathcomponent];             fromtrimmed = [fromtrimmed stringbydeletinglastpathcomponent];             [parents addobject:@".."];             [pieces insertobject:topiece atindex:0];         }      }      [relpath appendstring:[parents componentsjoinedbystring:@"/"]];     if(parents.count > 0) [relpath appendstring:@"/"];     else [relpath appendstring:@"./"];     [relpath appendstring:[pieces componentsjoinedbystring:@"/"]];      nslog(@"%@",relpath);      return relpath; }