//////////////////// // // Name: Range-based text formatting // Author: Shadow // Version: 1.0.0 // Date: 16.09.18 // Description: A class that formats text in a given // range without actually affecting its // property. Instead, the formatting is // done at output time. // Reference: Design Patterns in Modern C++ // ( Dmitri Nesteruk ) // //////////////////// #include #include #include #include #include enum class FORMAT : std::uint16_t { UNFORMATTED = 0, LOWERCASE, UPPERCASE }; class FormattedText; class TextRange { friend class FormattedText; friend bool operator == ( const TextRange&, const TextRange& ) noexcept; friend bool operator != ( const TextRange&, const TextRange& ) noexcept; friend std::ostream& operator << ( std::ostream&, const FormattedText& ); private: std::size_t start; std::size_t end; FORMAT format; TextRange( const std::size_t _start, const std::size_t _end ) : start{ _start }, end{ _end }, format{ FORMAT::UNFORMATTED } {} TextRange( const std::size_t _start, const std::size_t _end, const FORMAT _format ) : start{ _start }, end{ _end }, format{ _format } {} public: inline void remove_formatting() noexcept { this->format = FORMAT::UNFORMATTED; } inline void make_lowercase() noexcept { this->format = FORMAT::LOWERCASE; } inline void make_uppercase() noexcept { this->format = FORMAT::UPPERCASE; } bool covers( const std::size_t position ) const noexcept { return ( ( position >= this->start ) && ( position <= this->end ) ); } }; bool operator == ( const TextRange& left, const TextRange& right ) noexcept { return ( ( left.start == right.start ) && ( left.end == right.end ) && ( left.format == right.format ) ); } bool operator != ( const TextRange& left, const TextRange& right ) noexcept { return ( ( left.start != right.start ) || ( left.end != right.end ) || ( left.format != right.format ) ); } class FormattedText { friend std::ostream& operator << ( std::ostream&, const FormattedText& ); private: std::string* originalText; std::vector< TextRange > ranges; std::vector< TextRange >::const_iterator findRange( const TextRange& range ) { auto it{ this->ranges.cbegin() }; for ( ; it != this->ranges.cend(); ++it ) { if ( range == *it ) { break; } } return it; } public: FormattedText() = default; FormattedText( std::string* const text ) : originalText{ text } {} void constructRange( const std::size_t& start, const std::size_t& end, const FORMAT format ) { if ( start > end ) { throw std::logic_error{ "Error: start > end is an invalid range." }; } if ( end > originalText->length() ) { throw std::out_of_range{ "Error: _end > length is an invalid range." }; } TextRange newRange{ start, end, format }; if ( this->findRange( newRange ) == this->ranges.cend() ) { ranges.emplace_back( std::move( newRange ) ); } } void deleteRange( const std::size_t start, const std::size_t end, const FORMAT format ) { auto it{ this->findRange( TextRange{ start, end, format } ) }; if ( it != this->ranges.cend() ) { this->ranges.erase( it ); } } inline const std::string* const getOriginalText() const noexcept { return this->originalText; } inline void setOriginalText( std::string* const _text ) noexcept { this->originalText = _text; } }; std::ostream& operator << ( std::ostream& os, const FormattedText& text ) { if ( text.originalText ) { for ( std::size_t _index{ 0 }; _index < text.originalText->length(); ++_index ) { char c{ text.originalText->at( _index ) }; for ( const TextRange& _range : text.ranges ) { if ( _range.covers( _index ) ) { switch ( _range.format ) { case FORMAT::UNFORMATTED: break; case FORMAT::LOWERCASE: { c = std::tolower( c ); } break; case FORMAT::UPPERCASE: { c = std::toupper( c ); } break; } break; } } os << c; } } return os; } int main( int argc, char** argv ) { std::string quotation{ "The world is not beautiful, therefore it is." }; FormattedText txt{ "ation }; txt.constructRange( 0, 9, FORMAT::UPPERCASE ); txt.constructRange( 38, 42, FORMAT::UPPERCASE ); std::cout << "Original text:\n" << quotation << std::endl << "\nFormatted text:\n" << txt << std::endl << "\nMember variable:\n" << *txt.getOriginalText() << std::endl; return EXIT_SUCCESS; }