Functions for reading digits of pi in binary form

binary_pi_digits.py

"""Functions for reading binary files with the digits of pi stored
as 4-bit ints."""

def bin_file_to_digits(filename, the_type=str):
    raw_bytes = np.fromfile(filename, dtype=np.byte)
    for b in raw_bytes[0:10000]:
        digits = byte_to_digits(b)
        yield the_type(digits[0])
        yield the_type(digits[1])

def gen_bin(filename, the_type=str, chunksize=10000):
    with open(filename, 'rb') as f:
        while True:
            data = f.read(chunksize)
            if not data: break
            for b in data:
                print repr(b)
                digits = byte_to_digits(b)
                yield the_type(digits[0])
                yield the_type(digits[1])


def byte_to_digits(b):
    return ((b & 0xf0) >> 4, (b & 0x0f))