bloom-filter/bin/count_bits.py

#!/usr/local/pypy-1.6/bin/pypy

import sys

total_bits = 0
bits_set = 0

while True:
    block = sys.stdin.read(2 ** 19)
    if not block:
        break
    total_bits += len(block) * 8
    # print('got block of length %d' % len(block))
    for char in block:
        byte = ord(char)
        # print('got char %d' % byte)
        for exponent in range(8):
            bitmask = 2 ** exponent
            # print('checking mask %d' % bitmask)
            if byte & bitmask != 0:
                # print('adding 1 to count')
                bits_set += 1

print('%s set, %s present, %6.2f%%' % (bits_set, total_bits, bits_set * 100.0 / total_bits))