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Как создать класс с данными
evgeny2006: Коллеги! Документация по классам не очень общирная, поэтому решил обратиться к Вам за помощью. Требуется создать класс, скорее псевдо-класс, аналог помеченного общего блока в Фортране. В этом классе перечисляются переменные и массивы. Никакие действия с элементами класса не производятся. Отдельные программы и подпрограммы изменяют содержимое элементов класса. Где можно почитать по-подробнее или посмотреть примеры? Если кто-то уже создавал классы, не дадите посмотреть конкретный пример. Заранее благодарен.
Ответов - 1
gfilatov2002: evgeny2006 пишет: Где можно почитать по-подробнее или посмотреть примеры? Исходники Харбора - кладезь таких примеров. Например, см. вот такой класс из библиотеки hbmisc: [pre2] /* Harbour Project source code A class that reads a file one line at a time http://harbour-project.org/ Donated to the public domain on 2001-04-03 by David G. Holm <dholm@jsd-llc.com> */ #include "hbclass.ch" #include "fileio.ch" #define oF_ERROR_MIN 1 #define oF_CREATE_OBJECT 1 #define oF_OPEN_FILE 2 #define oF_READ_FILE 3 #define oF_CLOSE_FILE 4 #define oF_ERROR_MAX 4 #define oF_DEFAULT_READ_SIZE 4096 CREATE CLASS TFileRead VAR cFile // The filename VAR nHan // The open file handle VAR lEOF // The end of file reached flag VAR nError // The current file error code VAR nLastOp // The last operation done (for error messages) VAR cBuffer // The readahead buffer VAR nReadSize // How much to add to the readahead buffer on each read from the file METHOD New( cFile, nSize ) // Create a new class instance METHOD Open( nMode ) // Open the file for reading METHOD Close() // Close the file when done METHOD ReadLine() // Read a line from the file METHOD Name() // Retunrs the file name METHOD IsOpen() // Returns .T. if file is open METHOD MoreToRead() // Returns .T. if more to be read METHOD Error() // Returns .T. if error occurred METHOD ErrorNo() // Returns current error code METHOD ErrorMsg( cText ) // Returns formatted error message PROTECTED: METHOD EOL_pos() END CLASS METHOD New( cFile, nSize ) CLASS TFileRead IF nSize == NIL .OR. nSize < 1 // The readahead size can be set to as little as 1 byte, or as much as // 65535 bytes, but venturing out of bounds forces the default size. nSize := oF_DEFAULT_READ_SIZE ENDIF ::cFile := cFile // Save the file name ::nHan := F_ERROR // It's not open yet ::lEOF := .T. // So it must be at EOF ::nError := 0 // But there haven't been any errors ::nLastOp := oF_CREATE_OBJECT // Because we just created the class ::cBuffer := "" // and nothing has been read yet ::nReadSize := nSize // But will be in this size chunks RETURN Self METHOD Open( nMode ) CLASS TFileRead IF ::nHan == F_ERROR // Only open the file if it isn't already open. IF nMode == NIL nMode := FO_READ + FO_SHARED // Default to shared read-only mode ENDIF ::nLastOp := oF_OPEN_FILE ::nHan := FOpen( ::cFile, nMode ) // Try to open the file IF ::nHan == F_ERROR ::nError := FError() // It didn't work ::lEOF := .T. // So force EOF ELSE ::nError := 0 // It worked ::lEOF := .F. // So clear EOF ENDIF ELSE // The file is already open, so rewind to the beginning. IF FSeek( ::nHan, 0 ) == 0 ::lEOF := .F. // Definitely not at EOF ELSE ::nError := FError() // Save error code if not at BOF ENDIF ::cBuffer := "" // Clear the readahead buffer ENDIF RETURN Self METHOD ReadLine() CLASS TFileRead LOCAL cLine := "" LOCAL nPos ::nLastOp := oF_READ_FILE IF ::nHan == F_ERROR ::nError := F_ERROR // Set unknown error if file not open ELSE // Is there a whole line in the readahead buffer? nPos := ::EOL_pos() WHILE ( nPos <= 0 .OR. nPos > Len( ::cBuffer ) - 3 ) .AND. ! ::lEOF // Either no or maybe, but there is possibly more to be read. // Maybe means that we found either a CR or an LF, but we don't // have enough characters to discriminate between the three types // of end of line conditions that the class recognizes (see below). cLine := FReadStr( ::nHan, ::nReadSize ) IF Empty( cLine ) // There was nothing more to be read. Why? (Error or EOF.) ::nError := FError() IF ::nError == 0 // Because the file is at EOF. ::lEOF := .T. ENDIF ELSE // Add what was read to the readahead buffer. ::cBuffer += cLine ENDIF // Is there a whole line in the readahead buffer yet? nPos := ::EOL_pos() ENDDO // Is there a whole line in the readahead buffer? IF nPos <= 0 // No, which means that there is nothing left in the file either, so // return the entire buffer contents as the last line in the file. cLine := ::cBuffer ::cBuffer := "" ELSE // Yes. Is there anything in the line? IF nPos > 1 // Yes, so return the contents. cLine := Left( ::cBuffer, nPos - 1 ) ELSE // No, so return an empty string. cLine := "" ENDIF // Deal with multiple possible end of line conditions. DO CASE CASE SubStr( ::cBuffer, nPos, 3 ) == Chr( 13 ) + Chr( 13 ) + Chr( 10 ) // It's a messed up DOS newline (such as that created by a program // that uses "\r\n" as newline when writing to a text mode file, // which causes the '\n' to expand to "\r\n", giving "\r\r\n"). nPos += 3 CASE SubStr( ::cBuffer, nPos, 2 ) == Chr( 13 ) + Chr( 10 ) // It's a standard DOS newline nPos += 2 OTHERWISE // It's probably a Mac or Unix newline nPos++ ENDCASE ::cBuffer := SubStr( ::cBuffer, nPos ) ENDIF ENDIF RETURN cLine METHOD EOL_pos() CLASS TFileRead LOCAL nCRpos, nLFpos, nPos // Look for both CR and LF in the file read buffer. nCRpos := At( Chr( 13 ), ::cBuffer ) nLFpos := At( Chr( 10 ), ::cBuffer ) DO CASE CASE nCRpos == 0 // If there's no CR, use the LF position. nPos := nLFpos CASE nLFpos == 0 // If there's no LF, use the CR position. nPos := nCRpos OTHERWISE // If there's both a CR and an LF, use the position of the first one. nPos := Min( nCRpos, nLFpos ) ENDCASE RETURN nPos METHOD Close() CLASS TFileRead ::nLastOp := oF_CLOSE_FILE ::lEOF := .T. // Is the file already closed. IF ::nHan == F_ERROR // Yes, so indicate an unknown error. ::nError := F_ERROR ELSE // No, so close it already! FClose( ::nHan ) ::nError := FError() ::nHan := F_ERROR // The file is no longer open ::lEOF := .T. // So force an EOF condition ENDIF RETURN Self METHOD Name() CLASS TFileRead // Returns the filename associated with this class instance. RETURN ::cFile METHOD IsOpen() CLASS TFileRead // Returns .T. if the file is open. RETURN ::nHan != F_ERROR METHOD MoreToRead() CLASS TFileRead // Returns .T. if there is more to be read from either the file or the // readahead buffer. Only when both are exhausted is there no more to read. RETURN ! ::lEOF .OR. ! Empty( ::cBuffer ) METHOD Error() CLASS TFileRead // Returns .T. if an error was recorded. RETURN ::nError != 0 METHOD ErrorNo() CLASS TFileRead // Returns the last error code that was recorded. RETURN ::nError METHOD ErrorMsg( cText ) CLASS TFileRead STATIC sc_cAction := { "on", "creating object for", "opening", "reading from", "closing" } LOCAL cMessage, nTemp // Has an error been recorded? IF ::nError == 0 // No, so report that. cMessage := "No errors have been recorded for " + ::cFile ELSE // Yes, so format a nice error message, while avoiding a bounds error. IF ::nLastOp < oF_ERROR_MIN .OR. ::nLastOp > oF_ERROR_MAX nTemp := 1 ELSE nTemp := ::nLastOp + 1 ENDIF cMessage := iif( Empty( cText ), "", cText ) + "Error " + hb_ntos( ::nError ) + " " + sc_cAction[ nTemp ] + " " + ::cFile ENDIF RETURN cMessage [/pre2]
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