Python copyfileobj with progress bar

copyfileobj.py

from time import time
import sys

def mksize (bytes):
	suffixes = ("B", "kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB")
	suffixesLen = len(suffixes)

	for i in range(suffixesLen):
		if bytes < pow(1000, i + 1) or i + 1 == suffixesLen:
			return "%.2f %s" % (float(bytes) / pow(1024, i), suffixes[i])


def copyfileobj (fsrc, fdst, bufsize=16384, filesize=None):
	progress = 0
	percent = 0
	lastpercent = 0

	lasttime = time()
	lastprogress = 0

	lastprogress_speed = 0
	speed = 0

	eta = None

	while True:
		buf = fsrc.read(bufsize)
		if not buf:
			break
		fdst.write(buf)
		if filesize:
			progress += len(buf)
			timenow = time()
			elapsed = (timenow - lasttime)
			if elapsed >= 1: # Average it over 1 second
				speed = ((progress - lastprogress_speed) / elapsed) * (1/elapsed)
				lasttime = timenow
				lastprogress_speed = progress

				eta = "%d secs" % ((filesize - progress) / speed)

			percent = int((float(progress) / filesize) * 100)

			if percent != lastpercent:
				bar = ""
				barlen = 50
				if percent == 100:
					bar = "=" * barlen
				else:
					scaled_percent = percent/(100/barlen)
					for i in range(barlen):
						if i < scaled_percent-1:
							bar += "="
						elif i < scaled_percent:
							bar += ">"
						else:
							bar += " "

				print "%d%% [%s] %s (%s/s) %s          \r" % (percent, bar, mksize(progress), mksize(speed) if speed else "-.-- MB", "eta " + eta if eta else ""),
				sys.stdout.flush()

				lastpercent = percent
			lastprogress = progress
	print



# Example usage:
from os.path import getsize
filename = "/home/user/largefile.bin"

copyfileobj(open(filename, "rb"), open("/dev/null", "wb"), 16384, getsize(filename))