changeSubStrFontColor in TRichEdit Delphi

{
changeSubStrFontColor in TRichEdit
coded by: uragiristereo on august 28th, 2019
usage example:
  resetStrFontColor(RichEdit1, clBlack);
                    ^TRichedit ^TColor
  changeSubStrFontColor(RichEdit1, Edit1.Text, clRed);
                        ^TRichedit ^TEdit.Text ^TColor
}

function subStrCount(const subStr: string; const str: string): Integer;
begin
  if (Length(subStr)=0) or (Length(str)=0) or (Pos(subStr, str)=0) then
    Result:=0
  else
    Result:=(Length(str)-Length(StringReplace(str, subStr, '', [rfReplaceAll]))) div Length(subStr);
end;

function xPos(const subStr: string; const str: string; start: integer): Integer;
var
  s: String;
begin
  s:=Copy(str, start-1, Length(str));
  Result:=Pos(subStr, s)+start-1;
end;

procedure resetStrFontColor(const richEdit: TRichEdit; const color: TColor);
var
  lastPos: Integer;
begin
  lastPos:=richEdit.SelStart;
  richEdit.SelStart:=0;
  richEdit.SelLength:=Length(richEdit.Text);
  richEdit.SelAttributes.Color:=color;
  richEdit.SelStart:=lastPos;
end;

procedure changeSubStrFontColor(const richEdit: TRichEdit; const str: String; const color: TColor);
var
  x, y, lastPos: Integer;
begin
  y:=0;
  lastPos:=richEdit.SelStart;
  try
    for x:=1 to subStrCount(str, richEdit.Text) do begin
      if x=1 then
        richEdit.SelStart:=xPos(str, richEdit.Text, y)
      else
        richEdit.SelStart:=xPos(str, richEdit.Text, y)-2;
      richEdit.SelLength:=length(str);
      richEdit.SelAttributes.Color:=color;
      y:=richEdit.SelStart+length(str)+2;
    end;
  finally
  richEdit.SelStart:=lastPos;
  end;
end;