Sudoku: implement loading and saving sudoku files (as text).

Include sample.sudoku file that can be loaded and solved.


git-svn-id: https://svn.code.sf.net/p/lazarus-ccr/svn@7232 8e941d3f-bd1b-0410-a28a-d453659cc2b4

applications/sudoku/sample.sudoku

@@ -0,0 +1,9 @@
+--1--7--8
+-8-2---5-
+7-4---6--
+--2-86---
+5-------2
+---35-1--
+--9---7-5
+-7---3-1-
+8--7--3--

applications/sudoku/sudokumain.lfm

@@ -1,6 +1,6 @@
 object Form1: TForm1
   Left = 566
-  Height = 359
+  Height = 380
   Top = 203
   Width = 333
   HorzScrollBar.Page = 271
@@ -8,9 +8,10 @@ object Form1: TForm1
   ActiveControl = btnEdit
   BorderStyle = bsDialog
   Caption = 'Sudoku Solver'
-  ClientHeight = 359
+  ClientHeight = 380
   ClientWidth = 333
   OnActivate = FormActivate
+  OnCreate = FormCreate
   LCLVersion = '2.1.0.0'
   object SGrid: TStringGrid
     Left = 16
@@ -40,10 +41,13 @@ object Form1: TForm1
     TabOrder = 0
   end
   object btnSolve: TButton
+    AnchorSideRight.Control = SGrid
+    AnchorSideRight.Side = asrBottom
     Left = 208
     Height = 25
     Top = 312
-    Width = 75
+    Width = 100
+    Anchors = [akTop, akLeft, akRight]
     BorderSpacing.InnerBorder = 2
     Caption = 'Solve'
     OnClick = btnSolveClick
@@ -58,4 +62,34 @@ object Form1: TForm1
     OnClick = btnClearClick
     TabOrder = 3
   end
+  object btnSave: TButton
+    Left = 120
+    Height = 25
+    Top = 344
+    Width = 100
+    Caption = 'Save to file'
+    OnClick = btnSaveClick
+    TabOrder = 4
+  end
+  object btnLoad: TButton
+    Left = 16
+    Height = 25
+    Top = 344
+    Width = 100
+    Caption = 'Load from file'
+    OnClick = btnLoadClick
+    TabOrder = 5
+  end
+  object OpenDialog: TOpenDialog
+    Title = 'Open a Sudoku text file'
+    Filter = 'Sudoku files|*.sudoku|All files|*'
+    Options = [ofPathMustExist, ofFileMustExist, ofEnableSizing]
+    left = 264
+    top = 16
+  end
+  object SaveDialog: TSaveDialog
+    Options = [ofPathMustExist, ofEnableSizing]
+    left = 208
+    top = 16
+  end
 end

applications/sudoku/sudokumain.pas

@@ -39,14 +39,21 @@ type
 
   TForm1 = class(TForm)
     btnClear: TButton;
+    btnLoad: TButton;
+    btnSave: TButton;
     btnSolve: TButton;
     btnEdit: TButton;
+    OpenDialog: TOpenDialog;
+    SaveDialog: TSaveDialog;
     SGrid: TStringGrid;
     procedure btnClearClick(Sender: TObject);
     procedure btnEditClick(Sender: TObject);
+    procedure btnLoadClick(Sender: TObject);
+    procedure btnSaveClick(Sender: TObject);
     procedure btnSolveClick(Sender: TObject);
     procedure EditorKeyPress(Sender: TObject; var Key: char);
     procedure FormActivate(Sender: TObject);
+    procedure FormCreate(Sender: TObject);
     procedure SGridPrepareCanvas(sender: TObject; aCol, aRow: Integer;
       {%H-}aState: TGridDrawState);
     procedure SGridSelectEditor(Sender: TObject; {%H-}aCol, {%H-}aRow: Integer;
@@ -56,10 +63,17 @@ type
     theValues: TValues;
     function SolveSudoku: Boolean;
     procedure ShowSolution;
+    procedure LoadSudokuFromFile(const Fn: String);
+    procedure SaveSudokuToFile(const Fn: String);
+    function IsValidSudokuFile(Lines: TStrings): Boolean;
+    procedure LinesToGrid(Lines: TStrings);
+    procedure GridToLines(Lines: TStrings);
   public
     { public declarations }
   end;
 
+  ESudokuFile = Class(Exception);
+
 var
   Form1: TForm1; 
 
@@ -67,6 +81,12 @@ implementation
 
 {$R *.lfm }
 
+const
+  FileEmptyChar   = '-';
+  VisualEmptyChar = #32;
+  AllFilesMask = {$ifdef windows}'*.*'{$else}'*'{$endif};  //Window users are used to see '*.*', so I redefined this constant
+  SudokuFileFilter = 'Sudoku files|*.sudoku|All files|' + AllFilesMask;
+
 { TForm1 }
 
 procedure TForm1.btnEditClick(Sender: TObject);
@@ -75,6 +95,26 @@ begin
   SGrid.SetFocus;
 end;
 
+procedure TForm1.btnLoadClick(Sender: TObject);
+begin
+  if OpenDialog.Execute then
+  try
+    LoadSudokuFromFile(OpenDialog.Filename);
+  except
+    on E: Exception do ShowMessage(E.Message);
+  end;
+end;
+
+procedure TForm1.btnSaveClick(Sender: TObject);
+begin
+  if SaveDialog.Execute then
+  try
+    SaveSudokuToFile(SaveDialog.Filename);
+  except
+    on E: Exception do ShowMessage(E.Message);
+  end;
+end;
+
 procedure TForm1.btnClearClick(Sender: TObject);
 begin
   SGrid.Clean;
@@ -108,6 +148,12 @@ begin
   ClientWidth := 2 * SGrid.Left + SGrid.Width;
 end;
 
+procedure TForm1.FormCreate(Sender: TObject);
+begin
+  OpenDialog.Filter := SudokuFileFilter;
+  SaveDialog.Filter := SudokuFileFilter;
+end;
+
 
 procedure TForm1.SGridPrepareCanvas(sender: TObject; aCol, aRow: Integer;
   aState: TGridDrawState);
@@ -183,11 +229,122 @@ begin
     begin
       Ch := IntToStr(theValues[Col + 1, Row + 1])[1];
       if Ch = '0' then
-        Ch := #32;
+        Ch := VisualEmptyChar;
       SGrid.Cells[Col, Row] := Ch;
     end;
   end;
 end;
 
+procedure TForm1.LoadSudokuFromFile(const Fn: String);
+var
+  SL: TStringList;
+begin
+  SL := TStringList.Create;
+  try
+    SL.LoadFromFile(Fn);
+    SL.Text := AdjustLineBreaks(SL.Text);
+    if not IsValidSudokuFile(SL) then
+      Raise ESudokuFile.Create(Format('File does not seem to be a valid Sudoku file:'^m'"%s"',[Fn]));
+    LinesToGrid(SL);
+  finally
+    SL.Free
+  end;
+end;
+
+procedure TForm1.SaveSudokuToFile(const Fn: String);
+var
+  SL: TStringList;
+begin
+  SL := TStringList.Create;
+  try
+    GridToLines(SL);
+    {$if fpc_fullversion >= 30200}
+    SL.WriteBom := False;
+    {$endif}
+    SL.SaveToFile(Fn);
+  finally
+    SL.Free;
+  end;
+end;
+
+{
+A valid SudokuFile consists of 9 lines, each line consists of 9 characters.
+Only the characters '1'to '9' and spaces and FileEmptyChar ('-') are allowed.
+Empty lines and lines starting with '#' (comments) are discarded
+Future implementations may allow for adding a comment when saving the file
+}
+function TForm1.IsValidSudokuFile(Lines: TStrings): Boolean;
+var
+  i: Integer;
+  S: String;
+  Ch: Char;
+begin
+  Result := False;
+  for i := Lines.Count - 1 downto 0 do
+  begin
+    S := Lines[i];
+    if (S = '') or (S[1] = '#') then Lines.Delete(i);
+  end;
+  if (Lines.Count <> 9) then Exit;
+  for i := 0 to Lines.Count - 1 do
+  begin
+    S := Lines[i];
+    if (Length(S) <> 9) then Exit;
+    for Ch in S do
+    begin
+      if not (Ch in [FileEmptyChar, '1'..'9',VisualEmptyChar]) then Exit;
+    end;
+  end;
+  Result := True;
+end;
+
+{
+Since this should only be called if IsValidSudokuFile retruns True,
+We know that all lines consist of 9 chactres exactly and that there are exactly 9 lines in Lines
+}
+procedure TForm1.LinesToGrid(Lines: TStrings);
+var
+  Row, Col: Integer;
+  S: String;
+  Ch: Char;
+begin
+  for Row := 0 to Lines.Count - 1 do
+  begin
+    S := Lines[Row];
+    for Col := 0 to Length(S) - 1 do
+    begin
+      Ch := S[Col+1];
+      if (Ch = FileEmptyChar) then
+        Ch := VisualEmptyChar;
+      SGrid.Cells[Col, Row] := Ch;
+    end;
+  end;
+end;
+
+procedure TForm1.GridToLines(Lines: TStrings);
+var
+  ALine, S: String;
+  Ch: Char;
+  Row, Col: Integer;
+begin
+  Lines.Clear;
+  for Row := 0 to SGrid.RowCount - 1 do
+  begin
+    ALine := StringOfChar(FileEmptyChar,9);
+    for Col := 0 to SGrid.ColCount - 1 do
+    begin
+      S := SGrid.Cells[Col, Row];
+      if (Length(S) >= 1) then
+      begin
+        Ch := S[1];
+        if (Ch = VisualEmptyChar) then
+          Ch := FileEmptyChar;
+        ALine[Col+1] := Ch;
+      end;
+    end;
+    Lines.Add(ALine);
+  end;
+end;
+
 end.