I have two open file objects, dest and src. File object dest is opened for writing, with the seek position placed at some offset within the file, and file object src is opened for reading. What I need to do is simply read from the current position in src to EOF and transfer the contents to dest as quickly as possible.
If I were programming in Java, I could utilize the FileChannel#transferTo() method to perform zero-copy file I/O.
Does Python also support zero-copy?
Since version 3.3, Python has os.sendfile, which interfaces to various Unix variants' sendfile(2) zero-copy I/O interfaces. It operates on file descriptors, not general file-like objects. For older Pythons, there's py-sendfile.