1. Re: opening and writing files...
At 04:25 AM 11/01/01 -0800, you wrote:
>Heya all!
>
>Me again, this time i'm wondering this: When I open a file for write,
>it gets set to 0, I open a file for append, it starts at EOF, I open a file
>for update, it lets me seek around, but when I write bytes to the file
>at specific points, instead of adding the characters to the file, it
>overwrites whatever is there.
>
>How can I get it so that I can seek to a part of the file, and add
>characters? Again, I don't have these files in memory (trying to
>make the footprint during usage as tiny as possible)
>
>TIA,
>
>--"LEVIATHAN"
>
>
Here's one that moves the end of the file and
inserts the data at the specified offset.
It does it one byte at a time for low mem usage
(as requested), so it's going to be tragicly slow
if you want to insert data at the start of a big
file. Anyway, here it is.
Graeme.
--UNTESTED
include file.e
procedure insert_data(sequence path,
integer offset,
sequence data)
--insert data n at offset
integer fn,
gap,c
gap=length(data)
fn=open(path,"ub")
if seek(fn,-1) then end if -- goto EOF
-- move end of file
for x=where(fn)+gap-1 to offset+gap by -1 do
if seek(fn,x-gap) then end if
c=getc(fn)
if seek(fn,x) then end if
puts(fn,c)
end for
--write data
if seek(fn,offset) then end if
puts(fn,data)
close(fn)
end procedure
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