cenv.hpp

//
//  Copyright (c) 2012 Artyom Beilis (Tonkikh)
//
//  Distributed under the Boost Software License, Version 1.0. (See
//  accompanying file LICENSE_1_0.txt or copy at
//  http://www.boost.org/LICENSE_1_0.txt)
//
#ifndef BOOST_NOWIDE_CENV_H_INCLUDED
#define BOOST_NOWIDE_CENV_H_INCLUDED

#include <string>
#include <stdexcept>
#include <stdlib.h>
#include <boost/config.hpp>
#include <boost/nowide/stackstring.hpp>
#include <vector>

#ifdef BOOST_WINDOWS
#include <boost/nowide/windows.hpp>
#endif

namespace boost {
namespace nowide {
    #if !defined(BOOST_WINDOWS) && !defined(BOOST_NOWIDE_DOXYGEN)
    using ::getenv;
    using ::setenv;
    using ::unsetenv;
    using ::putenv;
    #else
    inline char *getenv(char const *key)
    {
        static stackstring value;
        
        wshort_stackstring name;
        if(!name.convert(key))
            return 0;

        static const size_t buf_size = 64;
        wchar_t buf[buf_size];
        std::vector<wchar_t> tmp;
        wchar_t *ptr = buf;
        size_t n = GetEnvironmentVariableW(name.c_str(),buf,buf_size);
        if(n == 0 && GetLastError() == 203) // ERROR_ENVVAR_NOT_FOUND
            return 0;
        if(n >= buf_size) {
            tmp.resize(n+1,L'\0');
            n = GetEnvironmentVariableW(name.c_str(),&tmp[0],static_cast<unsigned>(tmp.size() - 1));
            // The size may have changed
            if(n >= tmp.size() - 1)
                return 0;
            ptr = &tmp[0];
        }
        if(!value.convert(ptr))
            return 0;
        return value.c_str();
    }
    inline int setenv(char const *key,char const *value,int override)
    {
        wshort_stackstring name;
        if(!name.convert(key))
            return -1;
        if(!override) {
            wchar_t unused[2];
            if(!(GetEnvironmentVariableW(name.c_str(),unused,2)==0 && GetLastError() == 203)) // ERROR_ENVVAR_NOT_FOUND
                return 0;
        }
        wstackstring wval;
        if(!wval.convert(value))
            return -1;
        if(SetEnvironmentVariableW(name.c_str(),wval.c_str()))
            return 0;
        return -1;
    }
    inline int unsetenv(char const *key)
    {
        wshort_stackstring name;
        if(!name.convert(key))
            return -1;
        if(SetEnvironmentVariableW(name.c_str(),0))
            return 0;
        return -1;
    }
    inline int putenv(char *string)
    {
        char const *key = string;
        char const *key_end = string;
        while(*key_end!='=' && key_end!='\0')
            key_end++;
        if(*key_end == '\0')
            return -1;
        wshort_stackstring wkey;
        if(!wkey.convert(key,key_end))
            return -1;
        
        wstackstring wvalue;
        if(!wvalue.convert(key_end+1))
            return -1;

        if(SetEnvironmentVariableW(wkey.c_str(),wvalue.c_str()))
            return 0;
        return -1;
    }
    #endif
} // nowide
} // namespace boost

#endif
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