{-------------------------------------------------------------------------------
The contents of this file are subject to the Mozilla Public License
Version 1.1 (the "License"); you may not use this file except in compliance
with the License. You may obtain a copy of the License at
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WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for
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Alternatively, the contents of this file may be used under the terms of the
GNU General Public License Version 2 or later (the "GPL"), in which case
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replace them with the notice and other provisions required by the GPL.
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-------------------------------------------------------------------------------}
unit SynEditTextTabExpander;

{$I synedit.inc}

interface

uses
  Classes, SysUtils, Math, LazSynEditText, SynEditTextBase, SynEditTypes;

type

  // lines longer than "High(TLineLen) div 2" chars, will be stored as unknown
  TStoredLineLen = DWord;
  PStoredLineLen = ^TStoredLineLen;

  { TSynEditStringLineLenData }

  TSynEditStringLineLenData = class(TSynManagedStorageMem)
  private
    FRefCount: Integer;
    procedure SetLineLen(Index: Integer; const AValue: TStoredLineLen);
  protected
    function GetLineLen(Index: Integer): TStoredLineLen; virtual;
  public
    constructor Create;
    procedure IncRefCount;
    procedure DecRefCount;
    property RefCount: Integer read FRefCount;
    property LineLen[Index: Integer]: TStoredLineLen read GetLineLen write SetLineLen; default;
  end;

  { TSynEditStringTabData }

  TSynEditStringTabData = class(TSynEditStringLineLenData)
  private const
    // Offset to add to LengthOfLine, if Line has no tabs.
    // (Length will still be valid if tab-width changes)
    NO_TAB_IN_LINE_OFFSET = TStoredLineLen(
                                ( ( (high(TStoredLineLen) >> 1) and high(Integer) ) << 1) and
                              not ( (high(TStoredLineLen) >> 1) and high(Integer) )
                            );
    MAX_LINE_LEN_STORED = NO_TAB_IN_LINE_OFFSET - 2;
    LINE_INFO_UNKNOWN = 0; // invalid entry
  public const
    LINE_LEN_UNKNOWN  = TStoredLineLen(NO_TAB_IN_LINE_OFFSET- 1);
    (* Special values
       - LINE_INFO_UNKNOWN                        : Nothing know, not even if tab exists
       - LINE_LEN_UNKNOWN                         : Tab exists, but nothing else known (an empty line can't have tabs, so 0 can be used as marker)
       - LINE_LEN_UNKNOWN + NO_TAB_IN_LINE_OFFSET : NO Tab exists, but nothing else known
    *)
  private
    function GetHasTab(Index: Integer): Boolean; inline;
    function GetRawData(Index: Integer): TStoredLineLen;
  protected
    function GetLineLen(Index: Integer): TStoredLineLen; override;
  public
    procedure SetLineInfo(AnIndex: Integer; ALineLen: Integer; AnHasTab: Boolean); inline;
    procedure SetLineInfoUnknown(AnIndex: Integer); inline;
    procedure SetLineInfoUnknownEx(AnIndex: Integer; AnHasTab: Boolean); inline;
    function  GetLineInfo(AnIndex: Integer; out ALineLen: Integer; out AnHasTab: Boolean): boolean; inline;

    property HasTab[Index: Integer]: Boolean read GetHasTab;
    property LineLen[Index: Integer]: TStoredLineLen read GetLineLen; default;
    property RawData[Index: Integer]: TStoredLineLen read GetRawData;
  end;

const
  LINE_LEN_UNKNOWN = TSynEditStringTabData.LINE_LEN_UNKNOWN;

type

  { TSynEditStringTabExpanderBase }

  TSynEditStringTabExpanderBase = class(TSynEditStringsLinked)
  protected
    function  GetTabWidth : integer; virtual; abstract;
    procedure SetTabWidth(const AValue : integer); virtual; abstract;
  public
    constructor Create; virtual;
    property TabWidth: integer read GetTabWidth write SetTabWidth;
  end;

  { TSynEditStringTabExpanderCommon }

  TSynEditStringTabExpanderCommon = class(TSynEditStringTabExpanderBase)
  private
    FTabData: TSynEditStringTabData;

    procedure ReleaseTabData;
  protected
    procedure TextBufferChanged(Sender: TObject); virtual;
    procedure LineCountChanged(Sender: TSynEditStrings; AIndex, ACount : Integer); virtual;
    procedure LineTextChanged(Sender: TSynEditStrings; aIndex, aCount: Integer); virtual;
    procedure SetManager(AManager: TSynTextViewsManager); override;
    procedure SetSynStrings(AValue: TSynEditStrings); override;

    property TabData: TSynEditStringTabData read FTabData;
  public
    destructor Destroy; override;
  end;

  { TSynEditStringTabExpanderWithLongest }

  TSynEditStringTabExpanderWithLongest = class(TSynEditStringTabExpanderCommon)
  private
    FIndexOfLongestLine: Integer;
    FFirstUnknownLongestLine, FLastUnknownLongestLine: Integer;

  protected
    procedure InvalidateLongestLineInfo;
    procedure LineCountChanged(Sender: TSynEditStrings; AIndex, ACount : Integer); override;
    procedure LineTextChanged(Sender: TSynEditStrings; aIndex, aCount: Integer); override;

    function  GetIndexOfLongestLine(AStartIndex, AnEndIndex: IntIdx; out ALen: integer): integer; virtual;
    function  GetKnownLengthOfLine(AnIndex: IntIdx): integer; virtual;
    procedure SetLongestLineInfo(AnIndex: IntIdx; ALen: Integer); virtual;
    function  GetLengthOfLongestLine: integer; override;
  public
    constructor Create; override;
  end;


  TSynEditStringTabExpander = class(TSynEditStringTabExpanderWithLongest)
  private
    FTabWidth: integer;
    FLastLineHasTab: Boolean; // Last line, parsed by GetPhysicalCharWidths
    FLastLinePhysLen: Integer;
    FViewChangeStamp: int64;
    function ExpandedString(Index: integer): string;
    function ExpandedStringLength(Index: integer): Integer;
  protected
    procedure TextBufferChanged(Sender: TObject); override;
    function GetViewChangeStamp: int64; override;
    function  GetTabWidth : integer; override;
    procedure SetTabWidth(const AValue : integer); override;
    function  GetExpandedString(Index: integer): string; override;
    function GetKnownLengthOfLine(AnIndex: IntIdx): integer; override;
    function GetIndexOfLongestLine(AStartIndex, AnEndIndex: IntIdx; out ALen: integer): integer; override;
    procedure DoGetPhysicalCharWidths(Line: PChar; LineLen, Index: Integer; PWidths: PPhysicalCharWidth); override;
  public
    constructor Create; override;
  end;

  TSynEditStringTabExpanderClass = class of TSynEditStringTabExpanderBase;


implementation


function GetHasTabs(pLine: PChar): boolean;
begin
  if Assigned(pLine) then begin
    while (pLine^ <> #0) do begin
      if (pLine^ = #9) then break;
      Inc(pLine);
    end;
    Result := (pLine^ = #9);
  end else
    Result := FALSE;
end;

{ TSynEditStringLineLenData }

function TSynEditStringLineLenData.GetLineLen(Index: Integer): TStoredLineLen;
begin
  Result := PStoredLineLen(ItemPointer[Index])^;
end;

procedure TSynEditStringLineLenData.SetLineLen(Index: Integer; const AValue: TStoredLineLen);
begin
  PStoredLineLen(ItemPointer[Index])^ := AValue;
end;

constructor TSynEditStringLineLenData.Create;
begin
  inherited;
  ItemSize := SizeOf(TStoredLineLen);
  FRefCount := 1;
end;

procedure TSynEditStringLineLenData.IncRefCount;
begin
  inc(FRefCount);
end;

procedure TSynEditStringLineLenData.DecRefCount;
begin
  dec(FRefCount);
end;

{ TSynEditStringTabData }

function TSynEditStringTabData.GetHasTab(Index: Integer): Boolean;
var
  l: TStoredLineLen;
begin
  l := inherited GetLineLen(Index);
  Result := (l < NO_TAB_IN_LINE_OFFSET) and (l <> LINE_INFO_UNKNOWN);
end;

function TSynEditStringTabData.GetRawData(Index: Integer): TStoredLineLen;
begin
  Result := inherited GetLineLen(Index);
end;

function TSynEditStringTabData.GetLineLen(Index: Integer): TStoredLineLen;
begin
  Result := inherited GetLineLen(Index);
  if Result = LINE_INFO_UNKNOWN then
    Result := LINE_LEN_UNKNOWN // unkonwn len, but tabs exist
  else
  if (Result >= NO_TAB_IN_LINE_OFFSET) then
    Result := Result - NO_TAB_IN_LINE_OFFSET;
end;

procedure TSynEditStringTabData.SetLineInfo(AnIndex: Integer;
  ALineLen: Integer; AnHasTab: Boolean);
begin
  assert((not AnHasTab) or (ALineLen>0), 'TSynEditStringTabData.SetLineInfo: (not AnHasTab) or (ALineLen>0)');
  if ALineLen > MAX_LINE_LEN_STORED then
    ALineLen := LINE_LEN_UNKNOWN;
  if AnHasTab then
    inherited SetLineLen(AnIndex, ALineLen)
  else
    inherited SetLineLen(AnIndex, ALineLen + NO_TAB_IN_LINE_OFFSET);
end;

procedure TSynEditStringTabData.SetLineInfoUnknown(AnIndex: Integer);
begin
  inherited SetLineLen(AnIndex, LINE_INFO_UNKNOWN);
end;

procedure TSynEditStringTabData.SetLineInfoUnknownEx(AnIndex: Integer;
  AnHasTab: Boolean);
begin
  if AnHasTab then
    inherited SetLineLen(AnIndex, LINE_LEN_UNKNOWN)
  else
    inherited SetLineLen(AnIndex, LINE_LEN_UNKNOWN + NO_TAB_IN_LINE_OFFSET);
end;

function TSynEditStringTabData.GetLineInfo(AnIndex: Integer; out
  ALineLen: Integer; out AnHasTab: Boolean): boolean;
var
  d: TStoredLineLen;
begin
  d := inherited GetLineLen(AnIndex);
  Result := d <> LINE_INFO_UNKNOWN;
  AnHasTab := Result and (d < NO_TAB_IN_LINE_OFFSET);

  if not Result then
    ALineLen := LINE_LEN_UNKNOWN
  else
  if (d >= NO_TAB_IN_LINE_OFFSET) then
    ALineLen := d - NO_TAB_IN_LINE_OFFSET
  else
    ALineLen := d;
end;

{ TSynEditStringTabExpanderBase }

constructor TSynEditStringTabExpanderBase.Create;
begin
  inherited Create;
end;

{ TSynEditStringTabExpanderCommon }

procedure TSynEditStringTabExpanderCommon.ReleaseTabData;
var
  Data: TSynEditStringLineLenData;
begin
  Data := TSynEditStringTabData(NextLines.Ranges[Self]);
  if Assigned(Data) then begin
    Data.DecRefCount;
    if Data.RefCount = 0 then begin
      NextLines.Ranges[Self] := nil;
      Data.Free;
    end;
  end;
  FTabData := nil;
end;

procedure TSynEditStringTabExpanderCommon.TextBufferChanged(Sender: TObject);
var
  Data: TSynEditStringLineLenData;
begin
  // Using self, instead as class, to register tab-width-data
  // other shared edits can have different tab-width
  if (Sender <> nil) and
     (FTabData = TSynEditStringLineLenData(NextLines.Ranges[Self]))
  then
    exit;

  if Sender <> nil then begin
    Data := TSynEditStringLineLenData(TSynEditStrings(Sender).Ranges[Self]);
    if Assigned(Data) then begin
      Data.DecRefCount;
      if Data.RefCount = 0 then begin
        TSynEditStrings(Sender).Ranges[Self] := nil;
        Data.Free;
      end;
    end;
  end;

  FTabData := TSynEditStringTabData(NextLines.Ranges[Self]);
  if FTabData = nil then begin
    FTabData := TSynEditStringTabData.Create;
    NextLines.Ranges[Self] := FTabData;
  end
  else
    FTabData.IncRefCount;
end;

procedure TSynEditStringTabExpanderCommon.LineCountChanged(
  Sender: TSynEditStrings; AIndex, ACount: Integer);
begin
  //
end;

procedure TSynEditStringTabExpanderCommon.LineTextChanged(
  Sender: TSynEditStrings; aIndex, aCount: Integer);
var
  i: Integer;
begin
  for i := AIndex to AIndex + ACount - 1 do
    TabData.SetLineInfoUnknown(i);
end;

procedure TSynEditStringTabExpanderCommon.SetManager(
  AManager: TSynTextViewsManager);
begin
  if Manager <> nil then begin
    RemoveNotifyHandler(senrTextBufferChanged, @TextBufferChanged);
    RemoveChangeHandler(senrLineCount, @LineCountChanged);
    RemoveChangeHandler(senrLineChange, @LineTextChanged);
  end;
  if AManager = nil then
    ReleaseTabData;
  inherited SetManager(AManager);
  if Manager <> nil then begin
    AddChangeHandler(senrLineChange, @LineTextChanged);
    AddChangeHandler(senrLineCount, @LineCountChanged);
    AddNotifyHandler(senrTextBufferChanged, @TextBufferChanged);
  end;
end;

procedure TSynEditStringTabExpanderCommon.SetSynStrings(AValue: TSynEditStrings
  );
begin
  inherited SetSynStrings(AValue);
  if NextLines <> nil then begin
    if TabData = nil then
      TextBufferChanged(nil);
  end;
end;

destructor TSynEditStringTabExpanderCommon.Destroy;
begin
  ReleaseTabData;
  inherited Destroy;
  NextLines := nil;
end;

{ TSynEditStringTabExpanderWithLongest }

procedure TSynEditStringTabExpanderWithLongest.InvalidateLongestLineInfo;
begin
  FIndexOfLongestLine := -1;
  FFirstUnknownLongestLine := -1;
  FLastUnknownLongestLine := -1;
end;

procedure TSynEditStringTabExpanderWithLongest.LineCountChanged(
  Sender: TSynEditStrings; AIndex, ACount: Integer);
begin
  inherited LineCountChanged(Sender, AIndex, ACount);

  if (FIndexOfLongestLine >= AIndex) then
    FIndexOfLongestLine := FIndexOfLongestLine + ACount;

  if ACount < 0 then begin
    if (FIndexOfLongestLine >= AIndex+ACount) and (FIndexOfLongestLine < AIndex) then
      FIndexOfLongestLine := -1;
    if (FFirstUnknownLongestLine >= 0) then begin
      if (AIndex < FFirstUnknownLongestLine) then
        FFirstUnknownLongestLine := Max(AIndex, FFirstUnknownLongestLine + ACount);
      if (AIndex < FLastUnknownLongestLine) then
        FLastUnknownLongestLine := Max(AIndex, FLastUnknownLongestLine + ACount);
    end;

    exit;
  end;

  if (FFirstUnknownLongestLine < 0) or (AIndex < FFirstUnknownLongestLine) then
    FFirstUnknownLongestLine := AIndex;
  if (AIndex < FLastUnknownLongestLine) or (FLastUnknownLongestLine < 0) then
    FLastUnknownLongestLine := Max(AIndex, FLastUnknownLongestLine) +ACount;
end;

procedure TSynEditStringTabExpanderWithLongest.LineTextChanged(
  Sender: TSynEditStrings; aIndex, aCount: Integer);
begin
  inherited LineTextChanged(Sender, aIndex, aCount);

  if (FIndexOfLongestLine >= AIndex) and (FIndexOfLongestLine < AIndex+ACount) then
    FIndexOfLongestLine := -1;
  if (FFirstUnknownLongestLine < 0) or (AIndex < FFirstUnknownLongestLine) then
    FFirstUnknownLongestLine := AIndex;
  if AIndex+ACount-1 > FLastUnknownLongestLine then
    FLastUnknownLongestLine := AIndex+ACount-1;
end;

function TSynEditStringTabExpanderWithLongest.GetIndexOfLongestLine(
  AStartIndex, AnEndIndex: IntIdx; out ALen: integer): integer;
begin
  ALen := High(Result) - 5;
  Result := -1;
end;

function TSynEditStringTabExpanderWithLongest.GetKnownLengthOfLine(
  AnIndex: IntIdx): integer;
begin
  Result := High(Result) - 5;
end;

procedure TSynEditStringTabExpanderWithLongest.SetLongestLineInfo(
  AnIndex: IntIdx; ALen: Integer);
begin
  fIndexOfLongestLine := AnIndex;
end;

function TSynEditStringTabExpanderWithLongest.GetLengthOfLongestLine: integer;
var
  NewIdx, NewLen: Integer;
  Line1, Line2: Integer;
begin
  Result := 0;
  Line1 := 0;
  Line2 := Count - 1;

  if (fIndexOfLongestLine >= 0) and (fIndexOfLongestLine < Count) then begin
    Result := GetKnownLengthOfLine(FIndexOfLongestLine);
    if Result <> LINE_LEN_UNKNOWN then begin
      if (FFirstUnknownLongestLine < 0) then
        exit;
      // Result has the value from index
      Line1 := FFirstUnknownLongestLine;
      if (FLastUnknownLongestLine < Line2) then
        Line2 := FLastUnknownLongestLine;
    end
    else begin
      Result := 0;
      if (FFirstUnknownLongestLine < 0) then begin
        Line1 := fIndexOfLongestLine;
        Line2 := fIndexOfLongestLine;
      end
      else begin // TODO: Calculate for fIndexOfLongestLine, instead of extending the range
        Line1 := Min(fIndexOfLongestLine, FFirstUnknownLongestLine);
        if (FLastUnknownLongestLine < Line2) then
          Line2 := Max(fIndexOfLongestLine, FLastUnknownLongestLine);
      end;
    end;
  end;

  NewIdx := GetIndexOfLongestLine(Line1, Line2, NewLen);
  if NewLen > Result then begin
    SetLongestLineInfo(NewIdx, NewLen);
    Result := NewLen;
  end;

  FFirstUnknownLongestLine := -1;
  FLastUnknownLongestLine := -1;
end;

constructor TSynEditStringTabExpanderWithLongest.Create;
begin
  InvalidateLongestLineInfo;
  inherited Create;
end;

{ TSynEditStringTabExpander }

constructor TSynEditStringTabExpander.Create;
begin
  inherited Create;
  TabWidth := 8;
end;

function TSynEditStringTabExpander.GetTabWidth: integer;
begin
  Result := FTabWidth;
end;

procedure TSynEditStringTabExpander.SetTabWidth(const AValue: integer);
begin
  if FTabWidth = AValue then exit;

  {$PUSH}{$Q-}{$R-}
  FViewChangeStamp := FViewChangeStamp + 1;
  {$POP}

  FTabWidth := AValue;
  if NextLines <> nil then
    LineTextChanged(nil, 0, Count);
  InvalidateLongestLineInfo;
end;

function TSynEditStringTabExpander.GetViewChangeStamp: int64;
begin
  Result := inherited GetViewChangeStamp;
  {$PUSH}{$Q-}{$R-}
  Result := Result + FViewChangeStamp;
  {$POP}
end;

procedure TSynEditStringTabExpander.TextBufferChanged(Sender: TObject);
begin
  inherited TextBufferChanged(Sender);
  LineTextChanged(TSynEditStrings(Sender), 0, Count);
end;

function TSynEditStringTabExpander.ExpandedString(Index: integer): string;
var
  Line: String;
  CharWidths: TPhysicalCharWidths;
  i, j, l: Integer;
  HasTab: Boolean;
begin
// this is only used by trimmer.lengthOfLongestLine / which is not called, if a tab module is present
  Line := NextLines[Index];
  if (Line = '') or (not GetHasTabs(PChar(Line))) then begin
    Result := Line;
    // xxx wrong double width // none latin ...
    //TabData.SetLineInfo(Index, Length(Result, False));
  end else begin
    CharWidths := GetPhysicalCharWidths(Pchar(Line), length(Line), Index);
    l := 0;
    for i := 0 to length(CharWidths)-1 do
      l := l + (CharWidths[i] and PCWMask);
    SetLength(Result, l);

    l := 1;
    HasTab := False;
    for i := 1 to length(CharWidths) do begin
      if Line[i] <> #9 then begin
        Result[l] := Line[i];
        inc(l);
      end else begin
        HasTab := True;
        for j := 1 to (CharWidths[i-1] and PCWMask) do begin
          Result[l] := ' ';
          inc(l);
        end;
      end;
    end;
    TabData.SetLineInfo(Index, Length(Result), HasTab);
  end;
end;

function TSynEditStringTabExpander.ExpandedStringLength(Index: integer): Integer;
var
  Line: String;
  CharWidths: TPhysicalCharWidths;
  i: Integer;
begin
  Line := NextLines[Index];
  if (Line = '') then begin
    Result := 0;
    TabData.SetLineInfo(Index, 0, False);
  end else begin
    i := length(Line);
    SetLength(CharWidths{%H-}, i);
    DoGetPhysicalCharWidths(Pchar(Line), i, Index, @CharWidths[0]);
    Result := 0;
    for i := 0 to length(CharWidths)-1 do
      Result := Result + (CharWidths[i] and PCWMask);

    TabData.SetLineInfo(Index, Result, FLastLineHasTab);
  end;
end;

function TSynEditStringTabExpander.GetExpandedString(Index: integer): string;
begin
  if (Index >= 0) and (Index < Count) then begin
    if TabData.HasTab[Index] then
      Result := ExpandedString(Index)
    else
      Result := NextLines[Index];
  end else
    Result := '';
end;

procedure TSynEditStringTabExpander.DoGetPhysicalCharWidths(Line: PChar;
  LineLen, Index: Integer; PWidths: PPhysicalCharWidth);
var
  HasTab: Boolean;
  i, j: Integer;
begin
  inherited DoGetPhysicalCharWidths(Line, LineLen, Index, PWidths);
  HasTab := False;
  j := 0;
  for i := 0 to LineLen - 1 do begin
    if (PWidths^ and PCWMask) <> 0 then begin
      if Line^ = #9 then begin
        PWidths^ := (FTabWidth - (j mod FTabWidth) and PCWMask) or (PWidths^  and (not PCWMask));
        HasTab := True;
      end;
      j := j + (PWidths^ and PCWMask);
    end;
    inc(Line);
    inc(PWidths);
  end;
  FLastLineHasTab := HasTab;
  FLastLinePhysLen := j;
end;

function TSynEditStringTabExpander.GetKnownLengthOfLine(AnIndex: IntIdx
  ): integer;
begin
  Result := TabData[fIndexOfLongestLine];
end;

function TSynEditStringTabExpander.GetIndexOfLongestLine(AStartIndex,
  AnEndIndex: IntIdx; out ALen: integer): integer;
var
  Line: PChar;
  LineLen: Integer;
  CharWidths: PPhysicalCharWidth;
  i, j, m: Integer;
begin
  Result := 0;
  ALen := 0;
  try
    m := 0;
    CharWidths := nil;
    for i := AStartIndex to AnEndIndex do begin
      j := TabData[i];
      if j = LINE_LEN_UNKNOWN then begin
        // embedd a copy of ExpandedStringLength
        // allows one to re-use CharWidths
        Line := NextLines.GetPChar(i,LineLen); // NextLines[i];
        j := 0;
        if (LineLen = 0) then begin
          TabData.SetLineInfo(i, LineLen, False);
        end else begin
          if LineLen > m then begin
            ReAllocMem(CharWidths, LineLen * SizeOf(TPhysicalCharWidth));
            m := LineLen;
          end;
          DoGetPhysicalCharWidths(Line, LineLen, i, CharWidths);
          j := FLastLinePhysLen;
          TabData.SetLineInfo(i, j, FLastLineHasTab);
        end;
      end;

      if j > ALen then begin
        ALen := j;
        Result := i;
      end;
    end;
  finally
    ReAllocMem(CharWidths, 0);
  end;
end;

end.