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(*
  This is a wrapper around Synedits internal Storage. It allows TString based
  access to the Text.
  It relieves SynEditTextBase from having to support the full TStrings interface.
  It also hides all of the other methods that SynEditTextBase provides
*)

unit SynEditLines;

{$I synedit.inc}

interface

uses
  Classes, SysUtils, FileUtil, LazUtf8Classes, FPCAdds, SynEditTextBuffer;

type

  TSavedNotification = Procedure of Object;

  TSynLinesFileLineEndType =
    ( sfleSystem,
      sfleLoaded,
      sfleCrLf,
      sfleCr,
      sfleLf
    );

  { TSynEditLines }

  TSynEditLines = class(TStrings)
  private
    FFileLineEndType: TSynLinesFileLineEndType;
    FFileWriteLineEndType: TSynLinesFileLineEndType;
    FTextBuffer: TSynEditStringList;
    FOnSaved: TSavedNotification;
    function GetTextChangeStamp: int64;
  protected
    function Get(Index: integer): string; override;
    function GetCapacity: integer; override;
    function GetCount: integer; override;
    function GetObject(Index: integer): TObject; override;
    procedure Put(Index: integer; const S: string); override;
    procedure PutObject(Index: integer; AObject: TObject); override;
    procedure SetCapacity(NewCapacity: integer); override;
    procedure SetUpdateState(Updating: Boolean); override;
  public
    constructor Create(ATextBuffer: TSynEditStringList; OnSaved: TSavedNotification);
    function Add(const S: string): integer; override;
    procedure AddStrings(AStrings: TStrings); override;
    procedure Clear; override;
    procedure Delete(Index: integer); override;
    procedure Insert(Index: integer; const S: string); override;
    procedure Assign(Source: TPersistent); override;
    procedure LoadFromFile(const FileName: string); override;
    procedure SaveToFile(const FileName: string); override;
    property FileLineEndType: TSynLinesFileLineEndType read FFileLineEndType;
    property FileWriteLineEndType: TSynLinesFileLineEndType
             read FFileWriteLineEndType write FFileWriteLineEndType;
    property TextChangeStamp: int64 read GetTextChangeStamp;
  end;

implementation

type

{ TSynEditFiler }

  TSynEditFiler = class(TObject)
  private
    FLineEndString: String;
    FLineEndLen: Integer;
    FLineEndType: TSynLinesFileLineEndType;
    procedure SetLineEndType(const AValue: TSynLinesFileLineEndType);
  protected
    fBuffer: PChar;
    fBufPtr: Cardinal;
    fBufSize: Cardinal;
    fFiler: TFileStreamUtf8;
    procedure Flush; virtual;
    procedure SetBufferSize(NewSize: Cardinal);
  public
    constructor Create;
    destructor Destroy; override;
  public
    property LineEndType: TSynLinesFileLineEndType read FLineEndType write SetLineEndType;
  end;

constructor TSynEditFiler.Create;
const
  kByte = 1024;
begin
  inherited Create;
  LineEndType := sfleSystem;
  SetBufferSize(16 * kByte);
  fBuffer[0] := #0;
end;

destructor TSynEditFiler.Destroy;
begin
  Flush;
  fFiler.Free;
  SetBufferSize(0);
  inherited Destroy;
end;

procedure TSynEditFiler.SetLineEndType(const AValue: TSynLinesFileLineEndType);
begin
  FLineEndType := AValue;
  case FLineEndType of
    sfleCrLf: FLineEndString := #13#10;
    sfleCr:   FLineEndString := #13;
    sfleLf:   FLineEndString := #10;
    else
      FLineEndString := LineEnding;
  end;
  FLineEndLen := length(FLineEndString);
end;

procedure TSynEditFiler.Flush;
begin
end;

procedure TSynEditFiler.SetBufferSize(NewSize: Cardinal);
begin
  if NewSize <> fBufSize then begin
    ReallocMem(fBuffer, NewSize);
    fBufSize := NewSize;
  end;
end;

{ TSynEditFileReader }

type
  TSynEditFileReader = class(TSynEditFiler)
  protected
    fFilePos: TStreamSeekType;
    fFileSize: TStreamSeekType;
    procedure FillBuffer;
  public
    constructor Create(const FileName: string);
    function EOF: boolean;
    function ReadLine: string;
  end;

constructor TSynEditFileReader.Create(const FileName: string);
begin
  inherited Create;
  fFiler := TFileStreamUtf8.Create(FileName, fmOpenRead{ ToDo: or fmShareDenyWrite});
  fFileSize := fFiler.Size;
  fFiler.Seek(0, soFromBeginning);
end;

function TSynEditFileReader.EOF: boolean;
begin
  Result := (fBuffer[fBufPtr] = #0) and (fFilePos >= fFileSize);
end;

procedure TSynEditFileReader.FillBuffer;
var
  Count: Cardinal;
begin
  if fBufPtr >= fBufSize - 1 then
    fBufPtr := 0;
  Count := fFileSize - fFilePos;
  if Count >= fBufSize - fBufPtr then
    Count := fBufSize - fBufPtr - 1;
  fFiler.ReadBuffer(fBuffer[fBufPtr], Count);
  fBuffer[fBufPtr + Count] := #0;
  fFilePos := fFilePos + Count;
  fBufPtr := 0;
end;

function TSynEditFileReader.ReadLine: string;
var
  E, P, S: PChar;
begin
  Result := '';
  repeat
    S := PChar(@fBuffer[fBufPtr]);
    if S[0] = #0 then begin
      FillBuffer;
      S := PChar(@fBuffer[0]);
    end;
    E := PChar(@fBuffer[fBufSize]);
    P := S;
    while P + 2 < E do begin
      case P[0] of
        #10, #13:
          begin
            SetString(Result, S, P - S);
            // a single #13 is used in Mac OS files
            if (P[0] = #13) then begin
              if (P[1] = #10) then begin
                FLineEndType := sfleCrLf;
                inc(P);
              end
              else
                FLineEndType := sfleCr;
            end
            else
              FLineEndType := sfleLf;
            Inc(P);
            fBufPtr := P - fBuffer;
            exit;
          end;
        #0:
          if fFilePos >= fFileSize then begin
            fBufPtr := P - fBuffer;
            SetString(Result, S, P - S);
            exit;
          end;
      end;
      Inc(P);
    end;
    // put the partial string to the start of the buffer, and refill the buffer
    Inc(P);
    if S > fBuffer then
      StrLCopy(fBuffer, S, P - S);
    fBufPtr := P - S;
    fBuffer[fBufPtr] := #0;
    // if line is longer than half the buffer then grow it first
    if 2 * Cardinal(P - S) > fBufSize then
      SetBufferSize(fBufSize + fBufSize);
  until FALSE;
end;

{ TSynEditFileWriter }

type
  TSynEditFileWriter = class(TSynEditFiler)
  protected
    procedure Flush; override;
  public
    constructor Create(const FileName: string);
    procedure WriteLine(const S: string);
  end;

constructor TSynEditFileWriter.Create(const FileName: string);
begin
  inherited Create;
  fFiler := TFileStreamUtf8.Create(FileName, fmCreate);
  fFiler.Seek(0, soFromBeginning);
end;

procedure TSynEditFileWriter.Flush;
begin
  if fBufPtr > 0 then begin
    fFiler.WriteBuffer(fBuffer[0], fBufPtr);
    fBufPtr := 0;
  end;
end;

procedure TSynEditFileWriter.WriteLine(const S: string);
var
  L: Cardinal;
begin
  {$PUSH}{$HINTS OFF} // Lots of mixing signed/unsigned
  L := Length(S);
  repeat
    if fBufPtr + L + FLineEndLen <= fBufSize then begin
      if L > 0 then begin
        Move(S[1], fBuffer[fBufPtr], L);
        fBufPtr := fBufPtr + L;
      end;
      Move(FLineEndString[1], fBuffer[fBufPtr], FLineEndLen);
      Inc(fBufPtr, FLineEndLen);
      exit;
    end;
    Flush;
    if L + FLineEndLen > fBufSize then
      SetBufferSize(L + FLineEndLen);
  until FALSE;
  {$POP}
end;

{ TSynEditLines }

constructor TSynEditLines.Create(ATextBuffer: TSynEditStringList; OnSaved: TSavedNotification);
begin
  inherited Create;
  FTextBuffer := ATextBuffer;
  FFileWriteLineEndType := sfleSystem;
  FFileLineEndType := sfleSystem;
  FOnSaved := OnSaved;
end;

function TSynEditLines.GetTextChangeStamp: int64;
begin
  Result:=FTextBuffer.TextChangeStamp;
end;

function TSynEditLines.Get(Index: integer): string;
begin
  Result := FTextBuffer[Index];
end;

function TSynEditLines.GetCapacity: integer;
begin
  Result := FTextBuffer.Capacity;
end;

function TSynEditLines.GetCount: integer;
begin
  Result := FTextBuffer.Count;
end;

function TSynEditLines.GetObject(Index: integer): TObject;
begin
  Result := FTextBuffer.Objects[Index];
end;

procedure TSynEditLines.Put(Index: integer; const S: string);
begin
  FTextBuffer[Index] := S;
end;

procedure TSynEditLines.PutObject(Index: integer; AObject: TObject);
begin
  FTextBuffer.Objects[Index] := AObject;
end;

procedure TSynEditLines.SetCapacity(NewCapacity: integer);
begin
  FTextBuffer.Capacity := NewCapacity;
end;

procedure TSynEditLines.SetUpdateState(Updating: Boolean);
begin
  if Updating then
    FTextBuffer.BeginUpdate
  else
    FTextBuffer.EndUpdate;
end;

function TSynEditLines.Add(const S: string): integer;
begin
  Result := FTextBuffer.Add(S);
end;

procedure TSynEditLines.AddStrings(AStrings: TStrings);
begin
  FTextBuffer.AddStrings(AStrings);
end;

procedure TSynEditLines.Clear;
begin
  FTextBuffer.Clear;
end;

procedure TSynEditLines.Delete(Index: integer);
begin
  FTextBuffer.Delete(Index);
end;

procedure TSynEditLines.Insert(Index: integer; const S: string);
begin
  FTextBuffer.Insert(Index, S);
end;

procedure TSynEditLines.Assign(Source: TPersistent);
begin
  FTextBuffer.Assign(Source);
end;

procedure TSynEditLines.LoadFromFile(const FileName: string);
var
  Reader: TSynEditFileReader;
begin
  Reader := TSynEditFileReader.Create(FileName);
  try
    BeginUpdate;
    try
      Clear;
      while not Reader.EOF do
        Add(Reader.ReadLine);
    finally
      EndUpdate;
    end;
  finally
    FFileLineEndType := Reader.LineEndType;
    Reader.Free;
  end;
end;

procedure TSynEditLines.SaveToFile(const FileName: string);
var
  Writer: TSynEditFileWriter;
  i: integer;
begin
  Writer := TSynEditFileWriter.Create(FileName);
  try
    if FFileWriteLineEndType = sfleLoaded then
      Writer.LineEndType := FFileLineEndType
    else
      Writer.LineEndType := FFileWriteLineEndType;
    for i := 0 to Count - 1 do
      Writer.WriteLine(Get(i));
  finally
    Writer.Free;
  end;
  If Assigned(FOnSaved) then FOnSaved();
end;

end.