Python: regex on big file. Easy way?

I need to run a regex match over a file, but I'm faced with an unexpected problem: the file is too big to read() or mmap() in one call, File objects don't support the buf开发者_JAVA技巧fer() interface, and the regex module takes only strings or buffers.

Is there an easy way to do this?

The Python mmap module provides a nice Python-friendly way of memory mapping a file. On a 32-bit operating system, the maximum size of the file is will be limited to no more than a GB or maybe two, but on a 64-bit OS you will be able to memory map a file of arbitrary size (until storage sizes exceed 2⁶⁴, of course).

I've done this with files of up to 30 GB (the Wikipedia XML dump file) in Python with excellent results.