Standard C++ IOStreams and Locales

Listing 1: CaeserRotateFacet.h

#ifndef CAESAR_ROTATE_FACET_H
#define CAESAR_ROTATE_FACET_H

#include  <locale>
#include  <cstddef>

class CaesarRotateCvt : 
   public std::codecvt<char, char, std::mbstate_t>
{
   public:
      explicit CaesarRotateCvt( std::size_t refs = 0 );

   protected:
      virtual ~CaesarRotateCvt( );

      virtual std::codecvt_base::result 
      do_in( std::mbstate_t & state,
             const char * from,
             const char * from_end, 
             const char *& from_next,
             char * to, 
             char * to_limit, 
             char *& to_next ) const;
    
      virtual std::codecvt_base::result 
      do_out( std::mbstate_t & state,
              const char * from,
              const char * from_end,
              const char *& from_next,
              char * to,
              char * to_limit,
              char *& to_next ) const;
    
    virtual std::codecvt_base::result 
    do_unshift( std::mbstate_t & state,
                char * to,
                char * to_limit,
                char *& to_next ) const;

    virtual int do_encoding( ) const throw( );

    virtual bool do_always_noconv( ) const throw( );

    virtual int do_length( const std::mbstate_t &,
                           const char * from,
                           const char * end,
                           std::size_t max ) const;

    virtual int do_max_length( ) const throw( );
};

#endif