Insert bytes at the beginning of an existing file without overwriting existing bytes

Question

How can I add bytes to an existing file without:

overwriting existing bytes
reading the file

Keep the file on the disk in reverse order for use, appending to the end (which is actually the beginning). Use a function to access the file in reverse order when other code needs to access it normally. — umeboshi, Dec 26 '14 at 10:45
why the close vote? what part of the problem stztement is unclear? Requestor wants an efficient way to prepend to a disk file — Jasen, Dec 27 '14 at 04:08
I dont know why the close vote? what part of the problem stztement is unclear? — Muhammad Waqas Khan Abbasi, Dec 30 '14 at 06:51

score -1 · Accepted Answer · answered Dec 26 '14 at 10:51

-1

As you have described it you're going to need operating-system support to do that .
As far as I know this sort of thing is only easy for files stored on punched cards. or if you can add a shim between the userspace and the filesystem.

The best you can hope to do in java is override the file reading an writing code your own application is using to fake the presence of the extra bytes.

I hope you're not trying to corrupt perfectly good text files by adding UTF-8 BOM to the start.

answered Dec 26 '14 at 10:51

Jasen

11,837
2
30
48

This does not provide an answer to the question. To critique or request clarification from an author, leave a comment below their post. – Sulthan Allaudeen Dec 27 '14 at 04:36
1

some problems can be solved by a code sample. this is not one of them – Jasen Dec 27 '14 at 06:15
@Jasen thanks for your help your answer is almost correct. Thanks Again. and I don't know what happed to other people who vote down – Muhammad Waqas Khan Abbasi Dec 30 '14 at 06:55

Insert bytes at the beginning of an existing file without overwriting existing bytes

1 Answers1