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  1. #include <iostream>
  2. #include <regex>
  3. #include <string>
  4.  
  5. std::string extract_authority(std::string uri)
  6. {
  7.     // See: Apendix B from http://w...content-available-to-author-only...f.org/rfc/rfc2396.txt for regular expression
  8.     std::regex uri_exp(R"xxx(^(([^:/?#]+):)?(//([^/?#]*))?([^?#]*)(\?([^#]*))?(#(.*))?)xxx");
  9.     std::smatch matches;
  10.  
  11.     if (std::regex_match(uri, matches, uri_exp) && matches.size() >= 5)
  12.         return matches[4].str();
  13.  
  14.     return std::string();
  15. }
  16.  
  17. std::string trim_prefix(std::string s, std::string prefix)
  18. {
  19.     return s.find(prefix) == 0 ? s.substr(prefix.length()) : s;
  20. }
  21.  
  22. int main()
  23. {
  24.     std::vector<std::string> examples =
  25.     {
  26.         R"(http://w...content-available-to-author-only...i.edu/pub/ietf/uri/#Related)",
  27.         R"(http://w...content-available-to-author-only...s.com/user/)",
  28.         R"(ftp://f...content-available-to-author-only...o.za/rfc/rfc1808.txt)",
  29.         R"(gopher://spinaltap.micro.umn.edu/00/Weather/California/Los%20Angeles")",
  30.         R"(http://w...content-available-to-author-only...o.no/faq/compression-faq/part1.html)",
  31.         R"(mailto:mduerst@ifi.unizh.ch)",
  32.         R"(news:comp.infosystems.www.servers.unix")",
  33.         R"(telnet://melvyl.ucop.edu/)",
  34.     };
  35.  
  36.     for (auto example : examples)
  37.     {
  38.         auto auth = extract_authority(example);
  39.  
  40.         std::cout << '"' << trim_prefix(auth, "www.") << "\" (" << example << ")\n";
  41.     }
  42. }
Success #stdin #stdout 0s 3544KB
comments (?)
stdin 
Standard input is empty
stdout 
"ics.uci.edu" (http://w...content-available-to-author-only...i.edu/pub/ietf/uri/#Related)
"cplusplus.com" (http://w...content-available-to-author-only...s.com/user/)
"ftp.is.co.za" (ftp://f...content-available-to-author-only...o.za/rfc/rfc1808.txt)
"spinaltap.micro.umn.edu" (gopher://spinaltap.micro.umn.edu/00/Weather/California/Los%20Angeles")
"math.uio.no" (http://w...content-available-to-author-only...o.no/faq/compression-faq/part1.html)
"" (mailto:mduerst@ifi.unizh.ch)
"" (news:comp.infosystems.www.servers.unix")
"melvyl.ucop.edu" (telnet://melvyl.ucop.edu/)
https://ideone.com/4DkTyb
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
public

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