asked on

'ReadLn across lines'

Hi,

My problem seems to be with ReadLn. The following is code I have not written (but did pay for). I cannot get it to work. It does work in a compiled version from many years ago.

A line (0ÿNew Noteÿÿÿ-1ÿ80ÿ50ÿ65535ÿ16ÿ0ÿ1ÿ10ÿaþ
bÿ-1) in a datafile is read using

procedure TNotePool.Load(FileName : string);
var
DataFile : TextFile;
Line : string;
Note : TNote;
begin
AssignFile(DataFile, FileName);
Reset(DataFile);

while not EOF(DataFile) do
begin
Readln(DataFile, Line);

Note.ID := StrToInt(GetFieldFromLine(Line));
Note.Caption := GetFieldFromLine(Line);
Note.ImageFile := GetFieldFromLine(Line);
Note.IconFile := GetFieldFromLine(Line);
Note.NoteType := StrToInt(GetFieldFromLine(Line));
Note.Width := StrToInt(GetFieldFromLine(Line));
Note.Height := StrToInt(GetFieldFromLine(Line));
Note.Color := StrToInt(GetFieldFromLine(Line));
Note.IconSize := StrToInt(GetFieldFromLine(Line));
Note.IconLocation := StrToInt(GetFieldFromLine(Line));
Note.Transparent := Boolean(StrToInt(GetFieldFromLine(Line)));
Note.TextSize := StrToInt(GetFieldFromLine(Line));
Note.Memo := SetCRs(GetFieldFromLine(Line));
{ ATTENTION : TEMPORARILY }
Note.AggID := StrToInt(Line);

if OldLoad then
AddItem(Note)
else
AddItemRaw(Note);
end;

CloseFile(DataFile);
end;

The line that is read is cut into a first part on line 1 of the datafile and a second part on line 2 of the datafile. The line that is read must be put into the note (Memo field) and it must be cut in half (continuing after the carriage return) on the memo. Now, the line-separator þ (#254) that is used is not recognized by the

function TPool.GetFieldFromLine(var Str : string) : string;
var
Temp : string;
begin
Temp := Copy(Str, 1, Pos(#255, Str) - 1);
System.Delete(Str, 1, Pos(#255, Str));

Result := Temp;
end;

Therefore, the memo field remains empty and an exception is raised.

Strangely,

function TPool.SetCRs(Text : ansistring) : ansistring;
var
i : longint;
TempText : ansistring;
begin
for i := 1 to Length(Text) do
begin
if Text[i] = #254 then
TempText := TempText + #13
else
TempText := TempText + Text[i];
end;

Result := TempText;
end;

is supposed to work with the extracted memo-field, but, of course, if empty, it cannot.

Do you see how this is supposed to work? I will say this question is difficult, but I am clearly a beginner..

Thanks,

Ron dW

andrewjb

The line shouldn't be cut in the datafile - the þ is used as a line separator, not a standard CR.

The code looks OK (though there's no error handling at all).

After the ReadLn( DataFile , Line)

see how long 'Line' is

i.e. Line.Length()

Ron_de_Weijze

ASKER

Thanks for your comment, Andrew.
I agree that the line shouldn't be cut in the datafile.
However, this seems to be the way that the datafile is written in..

procedure TNotePool.Save(FileName : string);
var
DataFile : TextFile;
i : integer;
begin
AssignFile(DataFile, FileName);
Rewrite(DataFile);

for i := 0 to Count - 1 do
begin
WriteLn(DataFile,
i, #255,
TNoteItem(Item[i]).Caption, #255,
TNoteItem(Item[i]).ImageFile, #255,
TNoteItem(Item[i]).IconFile, #255,
TNoteItem(Item[i]).NoteType, #255,
TNoteItem(Item[i]).Width, #255,
TNoteItem(Item[i]).Height, #255,
TNoteItem(Item[i]).Color, #255,
TNoteItem(Item[i]).IconSize, #255,
TNoteItem(Item[i]).IconLocation, #255,
integer(TNoteItem(Item[i]).Transparent), #255,
TNoteItem(Item[i]).TextSize, #255,
KillCRs(TNoteItem(Item[i]).Memo), #255,
{ ATTENTION : TEMPORARILY }
m_SheetPool.m_ItemList.IndexOf(TNoteItem(Item[i]).
AggItem)
);
end;

CloseFile(DataFile);
end;

using..

function TPool.KillCRs(Text : ansistring) : ansistring;
var
i : longint;
TempText : ansistring;
begin
for i := 1 to Length(Text) do
begin
if Text[i] = #13 then
TempText := TempText + #254
else
TempText := TempText + Text[i];
end;

Result := TempText;
end;

Or would you say this code is nòt supposed to cut the line to be written in half after the þ line separator onto the datafile?

Thanks

Ron_de_Weijze

ASKER

BTW I wìll look into Line.Length() and let you know.

andrewjb

Indeed - it should remove the CRs so the line isn't cut.

Perhaps there's a LF got into there somehow.
Perhaps it's not really cut and it's just how your viewing it..

Ron_de_Weijze

ASKER

Thanks, I'll investigate and let you know ASAP!

kretzschmar

getting this result

0
New Note

-1
80
50
65535
16
0
1
10
aþb
-1

using this sample

unit Unit1;

interface

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

type
TForm1 = class(TForm)
Edit1: TEdit;
Button1: TButton;
Memo1: TMemo;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.DFM}

function SplitStr(Var AString : String; ADelim : String) : String;
var APos : Integer;
begin
Result := '';
APos := Pos(ADelim,AString);
if APos > 0 then
begin
Result := Copy(AString,1,APos-1);
AString := copy(Astring,APos+length(Adelim),MaxLongInt);
end
else
begin
Result := AString;
AString := '';
end;
end;

procedure TForm1.Button1Click(Sender: TObject);
var s : string;
begin
s := edit1.text;
memo1.lines.clear;
while s <> '' do
memo1.lines.add(splitstr(s,#255));

end;

end.

meikl ;-)

Ron_de_Weijze

ASKER

Thanks Andrew and Meikl,

The line is *really* cut in the datafile, for this is true after looking at the line ("a" over "b" in a note) written by the compiled code and the current code using EditPad. The line produced by the current code can be read by the compiled code but it cannot be read by the current code.

Text and Length(Text) in TPool.KillCRs are:

Text: 'a'#$D#$A'b'
Length(Text): Inaccessible value

I do not see LF #10.

I wished I'd understand this, otherwise I might resort to code like Meikl's.

Thanks again.

SOLUTION

andrewjb

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

ASKER CERTIFIED SOLUTION

kretzschmar

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

Ron_de_Weijze

ASKER

Thank you both!

I changed the

if Text[i] = #13

in KillCRs into

if Text[i] = #$A then
TempText := TempText + #254
else if Text[i] = #$D then
TempText := TempText

Looks like a change in Delphi itself (I use version 7.0)?

Case closed (for now).

Hope you don't mind sharing the points! :)