🚀 go-pugleaf

On Wed, 01 Feb 2006 15:17:32 +0100, Kim S <ks@pumpkin-post.dk> wrote:

> Can anybody suggest a way to replace a string in a binary file?

same length? different length? small file? big file?

krisztian pinter wrote:

> On Wed, 01 Feb 2006 15:17:32 +0100, Kim S <ks@pumpkin-post.dk> wrote:
> 
>> Can anybody suggest a way to replace a string in a binary file?
> 
> 
> same length? different length? small file? big file?
6 kb file size, original string length = new string length

On Wed, 01 Feb 2006 15:27:05 +0100, Kim S <ks@pumpkin-post.dk> wrote:


>>> Can anybody suggest a way to replace a string in a binary file?
>>   same length? different length? small file? big file?

> 6 kb file size, original string length = new string length

you are lucky :)

var
   F: file
   Buf: string;

...
   AssignFile(F, 'your file');
   Reset(F,1);
   SetLength(Buf, FileSize(F));
   BlockRead(F, Buf[1], Length(Buf));
   Buf := StringReplace(Buf, 'old', 'new');
   Seek(F, 0);
   BlockWrite(F, Buf[1], Length(Buf));
   CloseFile(F);


this is the essentials. you must add error detection. plus correct my
errors :)

krisztian pinter wrote:

> On Wed, 01 Feb 2006 15:27:05 +0100, Kim S <ks@pumpkin-post.dk> wrote:
> 
> 
>>>> Can anybody suggest a way to replace a string in a binary file?
>>>
>>>   same length? different length? small file? big file?
> 
> 
>> 6 kb file size, original string length = new string length
> 
> 
> you are lucky :)
> 
> var
>   F: file
>   Buf: string;
> 
> ...
>   AssignFile(F, 'your file');
>   Reset(F,1);
>   SetLength(Buf, FileSize(F));
>   BlockRead(F, Buf[1], Length(Buf));
>   Buf := StringReplace(Buf, 'old', 'new');
>   Seek(F, 0);
>   BlockWrite(F, Buf[1], Length(Buf));
>   CloseFile(F);
> 
> 
> this is the essentials. you must add error detection. plus correct my
> errors :)
> 
SUPER! SIMPLE! Works exactly like I wanted. Thanks.
A small correction:
   Buf := StringReplace(Buf, 'old', 'new', [rfReplaceAll]);
Regards,
Kim

other possibility:


var fs:     TFileStream
     st:     String;
begin

      fs := TFileStream.Create('Path');
      SetLength(st,fs.Size);
      fs.Read(PChar(st)^,fs.Size);
      st :=  StringReplace(st,'old Str',
	    'new Str',[rfReplaceAll,rfIgnoreCase]);
      fs.Position  := 0;
      fs.Write(PChar(st)^,Length(st));
      fs.Destroy;

On Wed, 01 Feb 2006 15:53:53 +0100, Kim S <ks@pumpkin-post.dk> wrote:

> SUPER! SIMPLE! Works exactly like I wanted. Thanks.
> A small correction:
>    Buf := StringReplace(Buf, 'old', 'new', [rfReplaceAll]);

don't forget to add error detection!!

na wrote:

> other possibility:
> 
> 
> var fs:     TFileStream
>     st:     String;
> begin
> 
>      fs := TFileStream.Create('Path');
>      SetLength(st,fs.Size);
>      fs.Read(PChar(st)^,fs.Size);
>      st :=  StringReplace(st,'old Str',
>         'new Str',[rfReplaceAll,rfIgnoreCase]);
>      fs.Position  := 0;
>      fs.Write(PChar(st)^,Length(st));
>      fs.Destroy;
Hmm. I must do something wrong. Neither of the 2 suggestions actually 
replace anything in the file. I only get an updated filestamp.
I have tried testing with Pos and found the 'old str' in the file so I 
suspect that the StringReplace function does not replace anything. This 
is my actual line:
st := StringReplace (st, 'DDDDDD', '020097', [rfReplaceAll,rfIgnoreCase]);
--
Kim

Kim S schrieb:
> na wrote:
> 
>> other possibility:
>>
>>
>> var fs:     TFileStream
>>     st:     String;
>> begin
>>
>>      fs := TFileStream.Create('Path');
>>      SetLength(st,fs.Size);
>>      fs.Read(PChar(st)^,fs.Size);
>>      st :=  StringReplace(st,'old Str',
>>         'new Str',[rfReplaceAll,rfIgnoreCase]);
>>      fs.Position  := 0;
>>      fs.Write(PChar(st)^,Length(st));
>>      fs.Destroy;
> Hmm. I must do something wrong. Neither of the 2 suggestions actually 
> replace anything in the file. I only get an updated filestamp.
> I have tried testing with Pos and found the 'old str' in the file so I 
> suspect that the StringReplace function does not replace anything. This 
> is my actual line:
> st := StringReplace (st, 'DDDDDD', '020097', [rfReplaceAll,rfIgnoreCase]);
> -- 
> Kim

StringReplace has problems with binary strings. - unfortunately
you must use Pos & Copy command in while loop.

jru

On Thu, 02 Feb 2006 10:40:02 +0100, na <no@com.de> wrote:

> StringReplace has problems with binary strings. - unfortunately
> you must use Pos & Copy command in while loop.


jeeeezus! i just looked its implementation, and it is a pretty ugly
procedure indeed! not only limited, but also low performance. i
thought it is a low-profile replacer.

what design decision led borland to provide procedure-pairs for most
string operations (like CompareStr and AnsiCompareStr), but only a
high profile implementation of StringReplace? this is crazy, man!

na wrote:

> Kim S schrieb:
> 
>> na wrote:
>>
>>> other possibility:
>>>
>>>
>>> var fs:     TFileStream
>>>     st:     String;
>>> begin
>>>
>>>      fs := TFileStream.Create('Path');
>>>      SetLength(st,fs.Size);
>>>      fs.Read(PChar(st)^,fs.Size);
>>>      st :=  StringReplace(st,'old Str',
>>>         'new Str',[rfReplaceAll,rfIgnoreCase]);
>>>      fs.Position  := 0;
>>>      fs.Write(PChar(st)^,Length(st));
>>>      fs.Destroy;
>>
>> Hmm. I must do something wrong. Neither of the 2 suggestions actually 
>> replace anything in the file. I only get an updated filestamp.
>> I have tried testing with Pos and found the 'old str' in the file so I 
>> suspect that the StringReplace function does not replace anything. 
>> This is my actual line:
>> st := StringReplace (st, 'DDDDDD', '020097', 
>> [rfReplaceAll,rfIgnoreCase]);
>> -- 
>> Kim
> 
> 
> StringReplace has problems with binary strings. - unfortunately
> you must use Pos & Copy command in while loop.
> 
> jru
Yep. That was it. Now all works as expected. Thanks again.
--
Kim

> 
> StringReplace has problems with binary strings. - unfortunately
> you must use Pos & Copy command in while loop.

try this code:

procedure ReplaceDirect(const Old,New: String; var AStr: String);
var p,i: Integer;
begin
     if Old = New then Exit;
     if Length(Old) <> Length(New) then
	raise Exception.Create('old and new have different length.');
     p := Pos(Old,AStr);
     while p > 0 do begin
         for i := 1 to Length(Old) do
            AStr[i+p-1] := new[i];
         p := PosEx(Old,AStr,p);
     end;
end;

na wrote:
> 
>>
>> StringReplace has problems with binary strings. - unfortunately
>> you must use Pos & Copy command in while loop.
> 
> 
> try this code:
> 
> procedure ReplaceDirect(const Old,New: String; var AStr: String);
> var p,i: Integer;
> begin
>     if Old = New then Exit;
>     if Length(Old) <> Length(New) then
>     raise Exception.Create('old and new have different length.');
>     p := Pos(Old,AStr);
>     while p > 0 do begin
>         for i := 1 to Length(Old) do
>            AStr[i+p-1] := new[i];
>         p := PosEx(Old,AStr,p);
>     end;
> end;
Thanks all, it's quite overwhelming!

As already mentioned, StringReplace is not suitable.  It will stop at the 
first #0 character.

The best option would be to use the Fastcode AnsiStringReplace function at 
http://fastcode.sourceforge.net/, which works with embedded #0's and is also 
approx 20x faster.

-- 
regards,
John

The Fastcode Project:
http://www.fastcodeproject.org/


"na" <no@com.de> wrote in message news:43e1e52a$1@newsgroups.borland.com...
>
>>
>> StringReplace has problems with binary strings. - unfortunately
>> you must use Pos & Copy command in while loop.
>
> try this code:
>
> procedure ReplaceDirect(const Old,New: String; var AStr: String);
> var p,i: Integer;
> begin
>     if Old = New then Exit;
>     if Length(Old) <> Length(New) then
> raise Exception.Create('old and new have different length.');
>     p := Pos(Old,AStr);
>     while p > 0 do begin
>         for i := 1 to Length(Old) do
>            AStr[i+p-1] := new[i];
>         p := PosEx(Old,AStr,p);
>     end;
> end;