Windows 環境変数適用 備忘録

環境変数を値に置き換える

#include <boost/regex.hpp>
#include <string>
#include <iostream>
#define WIN32_LEAN_AND_MEAN
#include <windows.h>

std::string getEnvValue(const std::string& str) {
  std::string result;
  std::string inp = str.substr( 1, str.size() - 2 );
  //std::cout << inp << std::endl;
  char buf[ 4096 ];
  DWORD sz = sizeof(buf);
  if( GetEnvironmentVariable( inp.c_str(), buf, sz ) > 0 ) {
    result = buf;
  }
  return result;
}

bool replaceEnv(std::string& str) {
  boost::regex r("(%[a-zA-Z0-9_]+%)");
  boost::smatch m;
  if( boost::regex_search(str, m, r) ) {
    std::string eval = m.str(1);
    std::string sval = getEnvValue( eval );
    while( std::string::npos != str.find(eval) ) {
      str.replace( str.find(eval), eval.size(), sval );
    }
    return true;
  }
  return false;
}

int main(int argc, char* argv[]) {
  std::string str = "%USERPROFILE%\\hoge\\fuga";
  while( replaceEnv( str ) ) {}
  std::cout << str << std::endl;

  

  return 0;
}