mmap( ) vs read( )

Question

I\'m writing a bulk ID3 tag editor in C. ID3 tags are usually at the beginning of an mp3 encoded file, although older (version 1) tags are at the end. The app is designed

Answer 1

If you're not normally going to be streaming the file in and then processing it, but rather hopping around (like read the tags at the front and then jump to the end, etc.) then I would use mmap simply because your code will be cleaner and easier to maintain treating the file as a large buffer without having to actually manage the the buffering and paging yourself.

As has been mentioned, if you're processing a lot of data disk I/O is likely going to dominate your processing anyway. mmap may be faster than read, but for reasonable implementations, it's likely not THAT much faster, especially on todays hardware which has continually got faster and faster while disk drives have been stuck at 7200 and 10,000 RPM for years and years.

So, go with mmap and make your code easy and neat.