What is the most efficient way to read a big text file backwards?

Question

What is the most efficient way to read a big text file backwards, line by line, using Windows API functions? For example, if a file is:

line 1
...
line 108777
line 108778

the output should be:

line 108778
line 108777
...
line 1

I want to write a C program for this. You don't need to write a code (but if you want, that's great), I am just interested in how to do this having in mind that files are big and that I want program to run as fast as it can.

Also, I am interested in which Windows API functions to use.

Answer 1

A more clever solution is to open the file, set the file-offset to the (end of the file - buffersize) and read (buffersize) bytes, u can parse the data in the buffer from back to front to find newlines and do whatever you want, and so on.

Answer 2

If performance is more important than memory utilization, I'd just do a buffered read of the entire text file into memory and then parse it in whatever order you like.

Take a look at memory mapped files, some advantages of which are discussed here.