#!/usr/bin/env python3.3
from time import perf_counter
from ssl import RAND_pseudo_bytes, RAND_bytes
from os import urandom as os_urandom

BYTES = (1, 4, 8, 16, 32, 64, 128)
LOOPS = 500000

dev_urandom = open("/dev/urandom", "rb").read
dev_urandom_nonbuf = open("/dev/urandom", "rb", buffering=0).read

PRNGS = [("urandom (fd)\t\t", dev_urandom),
         ("urandom (fd, no buf)\t", dev_urandom_nonbuf),
         ("os.urandom()\t\t", os_urandom),
         ("RAND_pseudo_bytes\t", RAND_pseudo_bytes),
         ("RAND_bytes\t\t", RAND_bytes)]


def benchmark(name, func, loops, *sizes):
    print(name, end="")
    for size in sizes:
        start = perf_counter()
        for i in range(loops):
            func(size)
        end = perf_counter()
        print("%0.03f\t" % (end - start), end="")
    print("")

fmt = "Loops: {}\t" + "\t{}" * len(BYTES)
print(fmt.format(LOOPS, *BYTES))
for name, func in PRNGS:
    benchmark(name, func, LOOPS, *BYTES)