RichEdit - Character-String Line Limit

The work break procedure for the rich edit seems to be the key. The example below will show you how to break the limit set by the default wordbreak proc (only needs to be set once), and then shows adding very long lines and how to read them back.
Let me know if there are question/problems

Regards,
Russell

---

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, ComCtrls;

type
  TForm1 = class(TForm)
    RichEdit1: TRichEdit;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1:      TForm1;

implementation
{$R *.DFM}

const
  WB_CLASS_WHITESPACE  =  0;
  WB_CLASS_LINEBREAK   =  1;
  WB_CLASS_DELIMITER   =  2;
  WB_CLASS_NORMALCHAR  =  3;

const
  WB_CLASSIFY          =  3;
  WB_MOVEWORDLEFT      =  4;
  WB_MOVEWORDRIGHT     =  5;
  WB_LEFTBREAK         =  6;
  WB_RIGHTBREAK        =  7;

const
  WBF_CLASS            = $0000000F;
  WBF_ISWHITE          = $00000010;
  WBF_BREAKLINE        = $00000020;
  WBF_BREAKAFTER       = $00000040;

const
  WHITESPACE:          Set of Char = [#9, #32];
  DELIMITERS:          Set of Char = ['"', '[', ']', '(', ')', ';', ',', '.', '\', ''''];
  LINEBREAKERS:        Set of Char = [#10, #13];

function IsInDelimiterList(C: Char): Boolean;
begin

  // Check for char in delimiter type list
  result:=(C in LINEBREAKERS);

end;

function EditWordBreakProcEx(pchText: PChar; ichCurrent: Integer; cch: Integer; Code: Integer): Integer; stdcall;
var  i:             Integer;
     found:         Boolean;
     initial_pos:   Integer;
begin

  result:=0;

  case Code of
     WB_LEFT           :
     begin
        while (not(IsInDelimiterList(pchText[ichCurrent])) and (ichCurrent > 0)) do Dec(ichCurrent);
        if (ichCurrent > 0) then
           result:=Succ(ichCurrent)
        else
           result:=-1;
     end;
     WB_RIGHT          :
     begin
        while (not(IsInDelimiterList(pchText[ichCurrent])) and (ichCurrent < cch)) do Inc(ichCurrent);
        if (ichCurrent > 0) then
           result:=ichCurrent
        else
           result:=-1;
     end;
     WB_ISDELIMITER    :
     begin
        result:=1
     end;
     WB_CLASSIFY       :
     begin
        if (pchText^ in WHITESPACE) then
           result:=WBF_ISWHITE or WB_CLASS_WHITESPACE
        else if (pchText^ in DELIMITERS) then
           result:=WBF_BREAKAFTER or WB_CLASS_DELIMITER
        else if (pchText^ in LINEBREAKERS) then
           result:=WBF_BREAKLINE or WB_CLASS_DELIMITER
        else
           result:=WB_CLASS_NORMALCHAR;
     end;
     WB_MOVEWORDLEFT   :
     begin
        Dec(ichCurrent);
        found:=False;
        while IsInDelimiterList(pchText[ichCurrent]) do Dec(ichCurrent);
        while (ichCurrent < cch) and not(found) and (ichCurrent >= 0) do
        begin
           found:=IsInDelimiterList(pchText[ichCurrent]);
           if (found and (ichCurrent >=0)) then
              result:=Succ(ichCurrent)
           else
           begin
              result:=MaxInt;
              Dec(ichCurrent);
           end;
         end;
     end;
     WB_MOVEWORDRIGHT  :
     begin
        if not(IsInDelimiterList(pchText[ichCurrent])) then
        begin
           while (not(IsInDelimiterList(pchText[ichCurrent])) and (ichCurrent < cch)) do Inc(ichCurrent);
        end;
        while (IsInDelimiterList(pchText[ichCurrent]) and (ichCurrent < cch)) do Inc(ichCurrent);
        if (ichCurrent < cch) then
           result:=Succ(ichCurrent)
        else
           result:=-1;
     end;
     WB_LEFTBREAK      :
     begin
        while (not(IsInDelimiterList(pchText[ichCurrent])) and (ichCurrent > 0)) do Dec(ichCurrent);
        if (ichCurrent > 0) then
           result:=ichCurrent
        else
           result:=-1;
     end;
     WB_RIGHTBREAK     :
     begin
        while (not(isInDelimiterList(pchText[ichCurrent])) and (ichCurrent < cch)) do Inc(ichCurrent);
        if (ichCurrent > 0) then
           result:=ichCurrent
        else
           result:=-1;
     end;
  end;

end;

function RichEditGetLine(Handle: HWND; Index: Integer): string;
var  Text: array [0..32768] of Char;
     L: Integer;
begin

  Word((@Text)^) := SizeOf(Text);
  L := SendMessage(Handle, EM_GETLINE, Index, Longint(@Text));
  if (Text[L - 2] = #13) and (Text[L - 1] = #10) then Dec(L, 2);
  SetString(Result, Text, L);

end;

procedure TForm1.Button1Click(Sender: TObject);
var  s:       String;
begin

  // Remove text limit from control
  RichEdit1.Perform(EM_LIMITTEXT, 0, $7FFFFFFF);

  // Set custom word break procedure
  RichEdit1.Perform(EM_SETWORDBREAKPROC, 0, Integer(@EditWordBreakProcEx));

  // Example of adding a really long line
  RichEdit1.Lines.Add(StringOfChar('X', 16 * 1024));

  // Get the first line, line 0. We can't use RichEdit.Lines[0] because the internal
  // buffer used is limited to 4KB.
  s:=RichEditGetLine(RichEdit1.Handle, 0);

  // Show line length
  ShowMessage(IntToStr(Length(s)));

end;

end.