STL Qt Creator Lubuntu

GetExtension is a file I/O std::string code snippet to get a filename's extension.

Thanks goes to Curtis Krauskopf, who supported me to improve the (terrible and error-prone) STL version GetExtension.

Download the Qt Creator project 'CppGetExtension' (zip)

Technical facts

Operating system(s) or programming environment(s)

Lubuntu 15.04 (vivid)

IDE(s):

Qt Creator 3.1.1

Project type:

Console application

C++ standard:

C++98

Compiler(s):

G++ 4.9.2

Libraries used:

STL: GNU ISO C++ Library, version 4.9.2

Qt project file: ./CppGetExtension/CppGetExtension.pro


include(../../ConsoleApplication.pri) #Or use the code below

# QT += core

# QT += gui

# greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

# CONFIG   += console

# CONFIG   -= app_bundle

# TEMPLATE = app

# CONFIG(release, debug|release) {

#   DEFINES += NDEBUG NTRACE_BILDERBIKKEL

# }

# QMAKE_CXXFLAGS += -std=c++11 -Wall -Wextra -Weffc++

# unix {

#   QMAKE_CXXFLAGS += -Werror

# }



include(../../Libraries/BoostAll.pri)



SOURCES += main.cpp

./CppGetExtension/main.cpp


#include <cassert>

#include <string>



#pragma GCC diagnostic push

#pragma GCC diagnostic ignored "-Weffc++"

#pragma GCC diagnostic ignored "-Wunused-local-typedefs"

#include <boost/filesystem.hpp>

#include <boost/xpressive/xpressive.hpp>

#pragma GCC diagnostic pop



//Returns the extension of a filename

//Assumes that the filename has an extension

//From http://www.richelbilderbeek.nl/CppGetExtension.htm

const std::string GetExtensionStl(const std::string& filename)

{

  const std::size_t i = filename.rfind('.');

  assert(i != std::string::npos && "Filename must contain a dot");

  assert(i != filename.size() - 1 && "Filename must not end with a dot");

  assert(filename[i+1] != '\\' && "Filename must have an extension");

  assert(filename[i+1] != '/' && "Filename must have an extension");

  return filename.substr(i,filename.size());

}





//Returns the extension of a filename

//From http://www.richelbilderbeek.nl/CppGetExtension.htm

const std::string GetExtensionBoostFilesystem(const std::string& filename)

{

  return boost::filesystem::extension(filename);

}



//Returns the extension of a filename

//From http://www.richelbilderbeek.nl/CppGetExtension.htm

const std::string GetExtensionBoostXpressive(const std::string& filename)

{

  const boost::xpressive::sregex rex

    = boost::xpressive::sregex::compile(

      "(.*)?(\\.[A-Za-z]*)" );

  boost::xpressive::smatch what;



  if( boost::xpressive::regex_match( filename, what, rex ) )

  {

    return what[2];

  }



  return "";

}



#include <iostream>



int main()

{

  assert(GetExtensionStl("test.abc") == ".abc");

  assert(GetExtensionStl("myfolder/test.abc") == ".abc");

  assert(GetExtensionStl("myfolder\\test.abc") == ".abc");

  assert(GetExtensionStl("myfolder/myfolder/test.abc") == ".abc");

  assert(GetExtensionStl("myfolder\\myfolder\\test.abc") == ".abc");



  assert(GetExtensionBoostFilesystem("test.abc") == ".abc");

  assert(GetExtensionBoostFilesystem("myfolder/test.abc") == ".abc");

  assert(GetExtensionBoostFilesystem("myfolder\\test.abc") == ".abc");

  assert(GetExtensionBoostFilesystem("myfolder/myfolder/test.abc") == ".abc");

  assert(GetExtensionBoostFilesystem("myfolder\\myfolder\\test.abc") == ".abc");



  assert(GetExtensionBoostXpressive("test.abc") == ".abc");

  assert(GetExtensionBoostXpressive("myfolder/test.abc") == ".abc");

  assert(GetExtensionBoostXpressive("myfolder\\test.abc") == ".abc");

  assert(GetExtensionBoostXpressive("myfolder/myfolder/test.abc") == ".abc");

  assert(GetExtensionBoostXpressive("myfolder\\myfolder\\test.abc") == ".abc");



  for (auto f: { GetExtensionStl, GetExtensionBoostFilesystem, GetExtensionBoostXpressive} )

  {

    assert(f("test.abc") == ".abc");

    assert(f("myfolder/test.abc") == ".abc");

    assert(f("myfolder\\test.abc") == ".abc");

    assert(f("myfolder/myfolder/test.abc") == ".abc");

    assert(f("myfolder\\myfolder\\test.abc") == ".abc");

  }

}

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(C++) GetExtension

Technical facts

Qt project file: ./CppGetExtension/CppGetExtension.pro

./CppGetExtension/main.cpp