interface/textfile.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        textfile.h
   3 // Purpose:     interface of wxTextFile
   4 // Author:      wxWidgets team
   5 // RCS-ID:      $Id$
   6 // Licence:     wxWindows license
   7 /////////////////////////////////////////////////////////////////////////////
   8
   9 /**
  10     @class wxTextFile
  11     @wxheader{textfile.h}
  12
  13     The wxTextFile is a simple class which allows to work with text files on line by
  14     line basis. It also understands the differences in line termination characters
  15     under different platforms and will not do anything bad to files with "non
  16     native" line termination sequences - in fact, it can be also used to modify the
  17     text files and change the line termination characters from one type (say DOS) to
  18     another (say Unix).
  19
  20     One word of warning: the class is not at all optimized for big files and thus
  21     it will load the file entirely into memory when opened. Of course, you should
  22     not
  23     work in this way with large files (as an estimation, anything over 1 Megabyte is
  24     surely too big for this class). On the other hand, it is not a serious
  25     limitation for small files like configuration files or program sources
  26     which are well handled by wxTextFile.
  27
  28     The typical things you may do with wxTextFile in order are:
  29
  30      Create and open it: this is done with either
  31     wxTextFile::Create or wxTextFile::Open
  32     function which opens the file (name may be specified either as the argument to
  33     these functions or in the constructor), reads its contents in memory (in the
  34     case of @c Open()) and closes it.
  35      Work with the lines in the file: this may be done either with "direct
  36     access" functions like wxTextFile::GetLineCount and
  37     wxTextFile::GetLine (@e operator[] does exactly the same
  38     but looks more like array addressing) or with "sequential access" functions
  39     which include wxTextFile::GetFirstLine/
  40     wxTextFile::GetNextLine and also
  41     wxTextFile::GetLastLine/wxTextFile::GetPrevLine.
  42     For the sequential access functions the current line number is maintained: it is
  43     returned by wxTextFile::GetCurrentLine and may be
  44     changed with wxTextFile::GoToLine.
  45      Add/remove lines to the file: wxTextFile::AddLine and
  46     wxTextFile::InsertLine add new lines while
  47     wxTextFile::RemoveLine deletes the existing ones.
  48     wxTextFile::Clear resets the file to empty.
  49      Save your changes: notice that the changes you make to the file will @b not be
  50     saved automatically; calling wxTextFile::Close or doing
  51     nothing discards them! To save the changes you must explicitly call
  52     wxTextFile::Write - here, you may also change the line
  53     termination type if you wish.
  54
  55
  56     @library{wxbase}
  57     @category{file}
  58
  59     @see wxFile
  60 */
  61 class wxTextFile
  62 {
  63 public:
  64     /**
  65         Constructor does not load the file into memory, use Open() to do it.
  66     */
  67     wxTextFile(const wxString& strFile) const;
  68
  69     /**
  70         Destructor does nothing.
  71     */
  72     ~wxTextFile() const;
  73
  74     /**
  75         Adds a line to the end of file.
  76     */
  77     void AddLine(const wxString& str,
  78                  wxTextFileType type = typeDefault) const;
  79
  80     /**
  81         Delete all lines from the file, set current line number to 0.
  82     */
  83     void Clear() const;
  84
  85     /**
  86         Closes the file and frees memory, @b losing all changes. Use Write()
  87         if you want to save them.
  88     */
  89     bool Close() const;
  90
  91     //@{
  92     /**
  93         Creates the file with the given name or the name which was given in the
  94         @ref ctor() constructor. The array of file lines is initially
  95         empty.
  96         It will fail if the file already exists, Open() should
  97         be used in this case.
  98     */
  99     bool Create() const;
 100     const bool Create(const wxString& strFile) const;
 101     //@}
 102
 103     /**
 104         Returns @true if the current line is the last one.
 105     */
 106     bool Eof() const;
 107
 108     /**
 109         Return @true if file exists - the name of the file should have been specified
 110         in the constructor before calling Exists().
 111     */
 112     bool Exists() const;
 113
 114     /**
 115         Returns the current line: it has meaning only when you're using
 116         GetFirstLine()/GetNextLine() functions, it doesn't get updated when
 117         you're using "direct access" functions like GetLine(). GetFirstLine() and
 118         GetLastLine() also change the value of the current line, as well as
 119         GoToLine().
 120     */
 121     size_t GetCurrentLine() const;
 122
 123     /**
 124         Get the line termination string corresponding to given constant. @e typeDefault
 125         is
 126         the value defined during the compilation and corresponds to the native format
 127         of the platform, i.e. it will be wxTextFileType_Dos under Windows,
 128         wxTextFileType_Unix under Unix (including Mac OS X when compiling with the
 129         Apple Developer Tools) and wxTextFileType_Mac under Mac OS (including
 130         Mac OS X when compiling with CodeWarrior).
 131     */
 132     static const char* GetEOL(wxTextFileType type = typeDefault) const;
 133
 134     /**
 135         This method together with GetNextLine()
 136         allows more "iterator-like" traversal of the list of lines, i.e. you may
 137         write something like:
 138     */
 139     wxString GetFirstLine() const;
 140
 141     /**
 142         Gets the last line of the file. Together with
 143         GetPrevLine() it allows to enumerate the lines
 144         in the file from the end to the beginning like this:
 145     */
 146     wxString GetLastLine();
 147
 148     /**
 149         Retrieves the line number @a n from the file. The returned line may be
 150         modified but you shouldn't add line terminator at the end - this will be done
 151         by wxTextFile.
 152     */
 153     wxString GetLine(size_t n) const;
 154
 155     /**
 156         Get the number of lines in the file.
 157     */
 158     size_t GetLineCount() const;
 159
 160     /**
 161         Get the type of the line (see also wxTextFile::GetEOL)
 162     */
 163     wxTextFileType GetLineType(size_t n) const;
 164
 165     /**
 166         Get the name of the file.
 167     */
 168     const char* GetName() const;
 169
 170     /**
 171         Gets the next line (see GetFirstLine() for
 172         the example).
 173     */
 174     wxString GetNextLine();
 175
 176     /**
 177         Gets the previous line in the file.
 178     */
 179     wxString GetPrevLine();
 180
 181     /**
 182         Changes the value returned by GetCurrentLine()
 183         and used by wxTextFile::GetFirstLine/GetNextLine().
 184     */
 185     void GoToLine(size_t n) const;
 186
 187     /**
 188         Guess the type of file (which is supposed to be opened). If sufficiently
 189         many lines of the file are in DOS/Unix/Mac format, the corresponding value will
 190         be returned. If the detection mechanism fails wxTextFileType_None is returned.
 191     */
 192     wxTextFileType GuessType() const;
 193
 194     /**
 195         Insert a line before the line number @e n.
 196     */
 197     void InsertLine(const wxString& str, size_t n,
 198                     wxTextFileType type = typeDefault) const;
 199
 200     /**
 201         Returns @true if the file is currently opened.
 202     */
 203     bool IsOpened() const;
 204
 205     //@{
 206     /**
 207         )
 208         Open() opens the file with the given name or the name which was given in the
 209         @ref ctor() constructor and also loads file in memory on
 210         success. It will fail if the file does not exist,
 211         Create() should be used in this case.
 212         The @e conv argument is only meaningful in Unicode build of wxWidgets when
 213         it is used to convert the file to wide character representation.
 214     */
 215     bool Open() const;
 216     const bool Open(const wxString& strFile) const;
 217     //@}
 218
 219     /**
 220         Delete line number @a n from the file.
 221     */
 222     void RemoveLine(size_t n) const;
 223
 224     /**
 225         )
 226         Change the file on disk. The @a typeNew parameter allows you to change the
 227         file format (default argument means "don't change type") and may be used to
 228         convert, for example, DOS files to Unix.
 229         The @e conv argument is only meaningful in Unicode build of wxWidgets when
 230         it is used to convert all lines to multibyte representation before writing them
 231         them to physical file.
 232         Returns @true if operation succeeded, @false if it failed.
 233     */
 234     bool Write(wxTextFileType typeNew = wxTextFileType_None) const;
 235
 236     /**
 237         The same as GetLine().
 238     */
 239     wxString operator[](size_t n) const;
 240 };
 241