from __future__ import print_function, division
import time

NUMBER_OF_RUNS = 4096
NUMBER_OF_WARMUP_RUNS = 100//2

def digits_genexp(number):
    return (int(digit) for digit in str(number))

def digits_generator(number):
   while number:
       number, digit = divmod(number, 10)
       yield digit

class Timed(object):
    def __init__(self):
        self._started = None
        self._ended = None

    def __enter__(self):
        self._started = time.time()
        return self

    def __exit__(self, *args):
        self._ended = time.time()
        return False

    @property
    def duration(self):
        return self._ended - self._started

print('start warmup (', NUMBER_OF_WARMUP_RUNS, 'runs)')
for _ in xrange(NUMBER_OF_WARMUP_RUNS):
    for i in xrange(NUMBER_OF_RUNS):
        list(digits_genexp(2**i))
print('warmup stage 1 finished')

for _ in xrange(NUMBER_OF_WARMUP_RUNS):
    for i in xrange(NUMBER_OF_RUNS):
        list(digits_generator(2**i))
print('warmup finished')

with Timed() as t:
    for i in xrange(NUMBER_OF_RUNS):
        list(digits_genexp(2**i))
print('avg genexp duration:', t.duration/NUMBER_OF_RUNS)

with Timed() as t:
    for i in xrange(NUMBER_OF_RUNS):
        list(digits_generator(2**i))
print('avg generatorfunc duration:', t.duration/NUMBER_OF_RUNS)

# pypy
# # 0 warmup runs
# avg genexp duration: 6.00620405748e-05
# avg generatorfunc duration: 0.00206580612576
#
# # 50 warmup runs
# avg genexp duration: 5.45402872376e-05
# avg generatorfunc duration: 0.00207115866942
#
# # 100 warmup runs
# avg genexp duration: 5.43720670976e-05
# avg generatorfunc duration: 0.00206778023858
#
# cpython (no jit which needs warmup time
# # 0 warmup runs
# avg genexp duration:  0.000265139678959
# avg generatorfunc duration:  0.000515451654792