reading a file in win32

Question

I'm programming an old-school mmorpg in win32 (It's supposed to run on very old machines), and I want to read a file that can be either ASCII or Unicode (rarely), and count the number of lines in it. due to the fact that those machines have very very low memory, I can't keep more than 4KB at once in the RAM.

any ideas? thanks

You only need to have enough storage for *one line* in the file. Not even that if you only have to count lines. Simply use the fgets() function. Keep calling it until it returns NULL. Check the returned string for `\n` at the end, increment the line counter when you see it. — Hans Passant, Apr 05 '12 at 18:12
Is this the client, or the server? Surely you can't make a game "massively multiplayer" without comparatively massive resources. — Wooble, Apr 05 '12 at 18:15

David Heffernan · Answer 1 · 2012-04-05T18:10:32.597

2

Read the file in small chunks at a time, say 1/10th the size of your memory budget. Count the line ends in each chunk.

The only real problem you face is that you need to deal with cr+lf pairs that span from the end of one chunk to the beginning of the next.

As an aside, surely you mean 4MB rather than 4KB?

edited Apr 05 '12 at 18:10

answered Apr 05 '12 at 17:55

David Heffernan

601,492
42
1,072
1,490

it might even be viable to just peak through the file ignoring everything except for return carriages and line feeds (depending on the line end convention). It's actually quite speedy to do it this way and the footprint would be nearly negligible. – Mike McMahon Apr 05 '12 at 18:01
@Mike That's exactly what I am proposing. – David Heffernan Apr 05 '12 at 18:02
wouldn't there be an issue with reading 128KB at a time when he said he can only store about 4KB in memory? Just wondering. – Mike McMahon Apr 05 '12 at 18:03
@Mike Oops, I assumed he meant MB. What version of Windows cannot handle 4KB of memory? – David Heffernan Apr 05 '12 at 18:09
my guess is that this is a SERIOUSLY old computer, otherwise I'm stumped. – Mike McMahon Apr 05 '12 at 18:10
which version of windows is limited to KBs? Windows 1? – David Heffernan Apr 05 '12 at 18:25

score 0 · Answer 2 · answered Apr 05 '12 at 18:06

0

Just to propose something a little different...

type foo.txt|find /C /V "~`!@#$%^&*()_+"

Or really just the following I think... been awhile

find /C /V "" foo.txt

answered Apr 05 '12 at 18:06

ficuscr

6,975
2
32
52

reading a file in win32

2 Answers2