Re: Insert into a file
Hi Harvey,
In addition to what the others have said, some applications approach this
problem by keeping a "list" of the changes to the text in memory which they
use to show the current file on screen as it would appear if saved at any
particular point. You could think of these kind of like Actions. Programs
like Word (Office) will save the list to the disk periodically in a thread
so that they won't be lost if something should happen (crash) before the
file is saved. You can also modify the Action list in memory if you want to
implement something like Undo or Redo.
When you actually save the file you have to, as the others have said,
resolve it so that you can write out a serial file (start to finish). I
don't know of any file system that allows you to insert content into a file
on disk or disc image.
Tom
"Harvey" <harveyab@juno.com> wrote in message
news:1173175748.702580.35770@c51g2000cwc.googlegroups.com...
I am ready to try adding "edit" to my App. I have done some searching
for ideas and am (a little) surprised not to find quite what I am
looking for.
Is there a way with CFile or some other file class to easily insert
(replace or delete) some data in an open file? What I have read seems
to indicate that I need to copy the file up to the edit point, do the
edit and change pointers and length as necessary and then copy the
rest of the file. This can be done by copying into a new file (and
rename, etc.) or read the whole file into memory and do it in the
buffer (either in-place or to a new buffer), etc.
It seems surprising to me that this is not already canned into an API
call or a MFC library so it would be as simple as:
Myfile.Insert(long EditPos, CString Insertion);
Myfile.Delete(long EditPos, long Size);
and/or:
Myfile.Replace(long EditPos, long Size, CString Insertion);
Don't many people need this kind of capability often?
I can't use CEdit (I don't think) because my use of files is really
very different than a "typical" editor.
What am I missing?
TIA,
Harvey