Extending boost::filesystem for Windows and Linux: Part 1

/****************************************************************
 *                                                              *
 *              Written bu Stanic Igor 2012/2013                *
 *              Implementation of helper fuctions               *
 *                                                              *
 *                                                              *
 ***************************************************************/

#include "Helpers.h"
typedef unsigned int UINT;

std::string Helpers::URIEnc(const std::string& source )
{
    static const std::map<char,std::string> reservedURIMappings =
    {PAIR('!', "%21"), PAIR('#', "%23"), PAIR('$', "%24"), PAIR('&', "%26"), /*PAIR('\'', "%27"),*/ PAIR('(', "%28"), PAIR(')', "%29"), PAIR('*', "%2A"), PAIR('+', "%2B"),
     PAIR(',', "%2C"), /*PAIR('/', "%2F"),*/ PAIR(':', "%3A"), PAIR(';', "%3B"), PAIR('=', "%3D"), PAIR('?', "%3F"), PAIR('@', "%40"), PAIR('[', "%5B"), PAIR(']', "%5D")};
    static const std::map<char, std::string> commonCharURIMappings =
    {PAIR(' ', "%20"), PAIR('\"', "%22"),PAIR('%', "%25"),/*PAIR('-', "%2D"),PAIR('.', "%2E"),*/PAIR('<', "%3C"),PAIR('>', "%3E"),
     PAIR('\\', "%5C"),PAIR('^', "%5E"),/*PAIR('_', "%5F"),*/
     PAIR('`', "%60"),PAIR('{', "%7B"),PAIR('|', "%7C"),PAIR('}', "%7D"),PAIR('~', "%7E")};


    std::string result;
    int len = source.length();
    std::stringstream ss;

    for(int i = 0; i < len; ++i)
    {
        //char c = source[i];
        int j = (int)source[i];
        //char seems to be negative number for unstandard chars
        if(j >= 0 && j <= 127)
        {
            char c = (char)j;
            std::map<char,std::string>::const_iterator reservedMapFind = reservedURIMappings.find(c);
            if(reservedMapFind != reservedURIMappings.end())
            {
                ss << (*reservedMapFind).second;
                continue;
            }

            std::map<char,std::string>::const_iterator commonMapFind = commonCharURIMappings.find(c);
            if(commonMapFind != commonCharURIMappings.end())
            {
                ss << (*commonMapFind).second;
                continue;
            }

            ss << c;
        }
        else
        {
            int ii = j;
            if (ii < 0)
                ii = 256 + ii;
            ss << "%";
            ss << hex << ii;
        }
    }
    result = ss.str();

    return result;
}

std::string Helpers::URIDec(const std::string source)
{
    static const std::map<std::string, char> reservedURIMappings =
    {PAIR("%21",'!'), PAIR("%23",'#'), PAIR("%24",'$'), PAIR("%26",'&'), PAIR("%27",'\''), PAIR("%28",'('), PAIR("%29",')'), PAIR("%2A",'*'), PAIR("%2B",'+'),
     PAIR("%2C",','), PAIR("%2F",'/'), PAIR("%3A",':'), PAIR("%3B",';'), PAIR("%3D",'='), PAIR("%3F",'?'), PAIR("%40",'@'), PAIR("%5B",'['), PAIR("%5D",']')};
    static const std::map<std::string, char> commonCharURIMappings =
    {PAIR("%20",' '), PAIR("%22",'\"'),PAIR("%25",'%'),/*PAIR("%2D",'-'),PAIR("%2E",'.'),*/PAIR("%3C",'<'),PAIR("%3E",'>'),
     PAIR("%5C",'\\'),PAIR("%5E",'^'),/*PAIR("%5F",'_'),*/
     PAIR("%60",'`'),PAIR("%7B",'{'),PAIR("%7C",'|'),PAIR("%7D",'}'),PAIR("%7E",'~')};

    std::stringstream ss;
    for(std::string::const_iterator it = source.cbegin(), end = source.cend(); it != end; ++it)
    {
        if(*it == '%')
        {
            std::string temp;
            std::string::const_iterator current = it;
            std::string::const_iterator limit = it + 2;
            do
            {
                temp += *current++;
            }while(current <= limit && limit < source.cend());

            auto iter_map = commonCharURIMappings.find(temp);
            if(iter_map != commonCharURIMappings.end())
            {
                ss << iter_map->second;
                it = limit;
                continue;
            }

            auto iter_map2 = reservedURIMappings.find(temp);
            if(iter_map2 != reservedURIMappings.end())
            {
                ss << iter_map2->second;
                it = limit;
            }

        }
        else
            ss << *it;
    }

    return ss.str();
}