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Posted by Saswat Praharaj on 04/08/05 10:26
Richard,
Thanks for the answer.
I understand that I can't do it the way I wanted .
I have changed my design.
Thanks ALL who answered.
-Saswat
On Apr 7, 2005 8:18 AM, Richard Lynch <ceo@l-i-e.com> wrote:
> On Wed, April 6, 2005 10:07 am, Saswat Praharaj said:
> > I need some help in searching string in a file.
> >
> > My requirement is to search the string,append something to the string .
> > Write the string back to the file without changing other parts of the
> > file.
> >
> > e.g
> > Suppose I have the following string in a file
> >
> >
> > Set-Cookie: T_COOKIE=127.0.0.1-saswat-9; path=/
> >
> >
> > The fixed string is "Set-Cookie: T_COOKIE="and rest of the string is
> > variable.
> > I would like to change the string "127.0.0.1-saswat-9" to say
> > "127.0.0.1-saswat-9-1234"
>
> Problem is, that's *MORE* bytes than are already there.
>
> You can't just smush a few more bytes in.
>
> You will *HAVE* to write out a new file.
>
> But you can read in only the first couple hundred bytes until you find
> your Set-Cookie: T_COOKIE, and then you write out the stuff before that,
> write out your new data, then read/write the whole rest of the file.
>
> You may also want to consider using, say, awk or sed or whatever from
> http://php.net/exec -- I don't expect them to be that much faster than
> PHP, but what do I know?
>
> > My constraint is : I don't want to read the whole file into a buffer
> > and work on that buffer as the file can be very large , sometimes more
> > than 10 mb.
> >
> > My advantage is : I know that I will get the search string in first
> > 200 bytes of the file , so I just need to read 200 bytes,play with
> > that and write it back (overwriting the first 200 bytes with new 200
> > some bytes) ..
>
> If it's really 200 bytes for 200 bytes, yeah, fopen(..., 'r+') will work.
>
> But if you can't squeeze your bytes into the same space as is already
> there, you can't do that.
>
> You might also be able, for the future, to start using:
> 127.0.0.1-saswat-9-0000000 and then you'd be able to replace up to
> 99999999 and get back something you can easily read/write/format to be
> meaningful.
>
> --
> Like Music?
> http://l-i-e.com/artists.htm
>
>
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