charSetTranslator.h

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#ifndef  charSetTranslator_h_included
#define  charSetTranslator_h_included

#include <utility>
#include <list>
#include <string>

namespace cxxtls
{

class CharSetTranslator
{   // CharSetTranslator
    char  mapping_[256];  


    bool  ok_;            

    char const *error_;   

    struct LhsSubrange
    {
        int offset_;         // the character in the left hand side
        int mappedOffset_;   // the index position in the right hand side

        LhsSubrange(int lhsChar, int mappedRhsPosition)
        : offset_(lhsChar)
        , mappedOffset_(mappedRhsPosition)
        {
        }

    };

    typedef std::list< LhsSubrange > LhsRange;

public:

    bool ok() const { return ok_; }               
    char const *error() const { return error_; }  

    CharSetTranslator(std::string const &inset, std::string const &outset)
    {

        ok_    = true;
        error_ = "";

        LhsRange lhs;

        char rhs[256];

        populateLhs(unEscape(inset).c_str(), lhs);
        populateRhs(unEscape(outset).c_str(), rhs);
        populateMapping(lhs, rhs);

    }

    char operator[] (unsigned char i) const { return mapping_[i]; }  


    std::string translate(std::string const &s) const
        ;

private:

    void populateLhs(char const *inset, LhsRange &lhs)
        ;

    void populateRhs(char const *set, char *rhs)
        ;

    void populateMapping(LhsRange const &lhs, char const *rhs)
        ;

public:

    static std::string unEscape(std::string const &in)
        ;


};  // CharSetTranslator

};  // namespace cxxlts


#endif