Help with low level file reading (Open as Input, etc, etc)

[piratelord]

I've an existing program I need to tweak that can open a non-text file at low level, find certain strings and replace with another, and write back to a new file.

The string replacement bit isn't a problem as that already works, the trouble is reading the file and writing it back.
At the moment, I'm just trying to read it, and write it back and check the file is exactly the same as originial.

Code is below, but the problems I'm encountering are an end of file error and it seems to be interpretating nulls as VBCrlf.

So for example, if you imagine # is a null, the string aaaa#444#dddd becomes

aaaa

4444

dddd

Not good!

Here's the code extract, SourceFile comes from the window interface.

fnum1 = FreeFile
Open SourceFile For Binary As fnum1
fnum2 = FreeFile
Open Left(SourceFile, Len(Trim(SourceFile)) - 4) & "2.NIF" For Append As fnum2
Do While Not EOF(fnum1)
    Line Input #fnum1, DataLine
    OutputData = OutputData + DataLine
Loop
Print #fnum2, OutputData;
Close fnum1
Close fnum2
 

[Killer42]

I'd say you are mixing up your file modes. Basically, if you are dealing with plain ASCII text, you can Open for Input, Out or Append, and use Input # and Print # to read/write. If you are dealing with non-text data which could have weird and wonderful characters, use Binary mode (for both files) and Get/Put to read/write them.

Note, I'm almost certain that EOF won't work properly for a Binary-mode file. Could be wrong, but if not you may need to track the number of bytes you transfer, and compare it to the number of bytes in the file (picked up using something like Lof() function at the start) to know when you're finished.