| // Copyright (C) 2003 Davis E. King ([email protected]) | |
| // License: Boost Software License See LICENSE.txt for the full license. | |
| namespace dlib | |
| { | |
| class bit_stream | |
| { | |
| /*! | |
| INITIAL VALUE | |
| is_in_write_mode() == false | |
| is_in_read_mode() == false | |
| WHAT THIS OBJECT REPRESENTS | |
| this object is a middle man between a user and the iostream classes. | |
| it allows single bits to be read/written easily to/from | |
| the iostream classes | |
| BUFFERING: | |
| This object will only read/write single bytes at a time from/to the | |
| iostream objects. Any buffered bits still in the bit_stream object | |
| when it is closed or destructed are lost if it is in read mode. If | |
| it is in write mode then any remaining bits are guaranteed to be | |
| written to the output stream by the time it is closed or destructed. | |
| !*/ | |
| public: | |
| bit_stream ( | |
| ); | |
| /*! | |
| ensures | |
| - #*this is properly initialized | |
| throws | |
| - std::bad_alloc | |
| !*/ | |
| virtual ~bit_stream ( | |
| ); | |
| /*! | |
| ensures | |
| - all memory associated with *this has been released | |
| !*/ | |
| void clear ( | |
| ); | |
| /*! | |
| ensures | |
| - #*this has its initial value | |
| throws | |
| - std::bad_alloc | |
| if this exception is thrown then *this is unusable | |
| until clear() is called and succeeds | |
| !*/ | |
| void set_input_stream ( | |
| std::istream& is | |
| ); | |
| /*! | |
| requires | |
| - is_in_write_mode() == false | |
| - is_in_read_mode() == false | |
| - is is ready to give input | |
| ensures | |
| - #is_in_write_mode() == false | |
| - #is_in_read_mode() == true | |
| - #*this will now be reading from is | |
| throws | |
| - std::bad_alloc | |
| !*/ | |
| void set_output_stream ( | |
| std::ostream& os | |
| ); | |
| /*! | |
| requires | |
| - is_in_write_mode() == false | |
| - is_in_read_mode() == false | |
| - os is ready to take output | |
| ensures | |
| - #is_in_write_mode() == true | |
| - #is_in_read_mode() == false | |
| - #*this will now write to os | |
| throws | |
| - std::bad_alloc | |
| !*/ | |
| void close ( | |
| ); | |
| /*! | |
| requires | |
| - is_in_write_mode() == true || is_in_read_mode() == true | |
| ensures | |
| - #is_in_write_mode() == false | |
| - #is_in_read_mode() == false | |
| !*/ | |
| bool is_in_write_mode ( | |
| ) const; | |
| /*! | |
| ensures | |
| - returns true if *this is associated with an output stream object | |
| - returns false otherwise | |
| !*/ | |
| bool is_in_read_mode ( | |
| ) const; | |
| /*! | |
| ensures | |
| - returns true if *this is associated with an input stream object | |
| - returns false otherwise | |
| !*/ | |
| void write ( | |
| int bit | |
| ); | |
| /*! | |
| requires | |
| - is_in_write_mode() == true | |
| - bit == 0 || bit == 1 | |
| ensures | |
| - bit will be written to the ostream object associated with *this | |
| throws | |
| - std::ios_base::failure | |
| if (there was a problem writing to the output stream) then | |
| this exception will be thrown. #*this will be unusable until | |
| clear() is called and succeeds | |
| - any other exception | |
| if this exception is thrown then #*this is unusable | |
| until clear() is called and succeeds | |
| !*/ | |
| bool read ( | |
| int& bit | |
| ); | |
| /*! | |
| requires | |
| - is_in_read_mode() == true | |
| ensures | |
| - the next bit has been read and placed into #bit | |
| - returns true if the read was successful, else false | |
| (ex. false if EOF has been reached) | |
| throws | |
| - any exception | |
| if this exception is thrown then #*this is unusable | |
| until clear() is called and succeeds | |
| !*/ | |
| void swap ( | |
| bit_stream& item | |
| ); | |
| /*! | |
| ensures | |
| - swaps *this and item | |
| !*/ | |
| private: | |
| // restricted functions | |
| bit_stream(bit_stream&); // copy constructor | |
| bit_stream& operator=(bit_stream&); // assignment operator | |
| }; | |
| inline void swap ( | |
| bit_stream& a, | |
| bit_stream& b | |
| ) { a.swap(b); } | |
| /*! | |
| provides a global swap function | |
| !*/ | |
| } | |