16 bit Binary conversion

Question

I have found several ways to convert both Integer and Float values to binary, and they each have their issues. I need to take an Integer/Float input between values of 0 and 10,000, convert to a 16-digit (exactly) binary string, manipulate the bits at random, and convert back to an Integer/Float (depending on the parameter).

However, I have been using the following code:

def convert_to_binary(value):
    '''
    Converts a float to a 16-bit binary string.
    '''
    [d] = struct.unpack('>Q', struct.pack('>d', value))
    return str('{:016b}'.format(d))

def convert_back(bin_num):
    ''' 
    Converts binary string to a float. 
    '''
    print type(bin_num) 
        print bin_num
    bf = int_to_bytes(int(bin_num, 2), 8)  # 8 bytes needed for IEEE 754 binary64.
        print struct.unpack('>d', bf)[0]
    return struct.unpack('>d', bf)[0]

#   return struct.unpack('d', struct.pack('Q', bin_num))[0]
    #bin_num.pack('B*').unpack('g').first

def int_to_bytes(n, minlen=0):  # Helper function
    '''
    Turns integer/long to byte string.
    '''
    nbits = n.bit_length() + (1 if n < 0 else 0)  # +1 for any sign bit.
    nbytes = (nbits+7) // 8  # Number of whole bytes.
    b = bytearray()
    for _ in range(nbytes):
        b.append(n & 0xff)
        n >>= 8
    if minlen and len(b) < minlen:  # Zero padding needed?
        b.extend([0] * (minlen-len(b)))
    return bytearray(reversed(b))  # High bytes first.

And the result is this (in picture form since I couldn't copy and paste from my terminal):

I understand that there are different types of binary (signed/unsigned, different bit numbers, etc.), but I need my output to be what I think is unsigned short... all of my numbers are positive values, and to allow for the bit manipulation I later use, they need to be exactly 16 digits long --> (If they are float values, I can use the extra digits of binary but just alter the first 16, and the ones that follow are just what follows the decimal point, right?)

Firstly, should I write functions for both a Float input and an Integer input?

Secondly, how do I change my code to allow for the desired output without simply using pop, etc. to cut the length of the binary to 16?

Answer 1

I had the same problem and I found a simpler and shorter solution.

Here's an example:

Encode:

In [1]: val = 15

In [2]: bin_ = '{0:016b}'.format(val)
In [3]: bin_
Out[3]: '0000000000001111'

Or:

In [4]: bin_ = bin(val)[2:].zfill(16)
In [5]: bin_
Out[5]: '0000000000001111'

---

Decode:

In [6]: int(bin_, 2)
Out[6]: 15