Encoding a selection of sets into an int and decoding.

int_coding.py

def make_id( v, bit_map ):
    bits_used = 0
    _id = 0

    for pair in zip( v, bit_map ):
        _id += pair[0] * (2 ** bits_used )
        bits_used += pair[1]

    return _id


def unmake_id( vid, bit_map ):
    total_bits = 0
    remainder = []

    for b in bit_map:
        total_bits += b
        a = ( ( vid - sum( remainder ) ) % ( 2 ** total_bits ) ) / ( 2 ** ( total_bits - b ) )
        remainder.append( a )

    return remainder


def make_bit_map( max_values ):
    bit_map = []

    for v in max_values:
        i = 1
        while 2 ** i < v - 1:
            i += 1
        bit_map.append( i )

    return bit_map



maxs   = [ 16, 8, 8, 22, 16]
values = [15, 3, 0, 1, 14]

print '{:<20}'.format( 'max values per slot' ),
for m in maxs:
    print '{:>4}'.format(m),
print

bits = make_bit_map( maxs )
print '{:<20}'.format( 'num bits per slot' ),
for b in bits:
    print '{:>4}'.format(b),
print

print '{:<20}'.format( 'original values' ),
for v in values:
    print '{:>4}'.format( v ),
print
print

set_id = make_id( values, bits )
print '{:<22}'.format( 'encoded value' ),
print '{}'.format( set_id )

print '{:<20}'.format( 'decoded value' ),
for v in unmake_id( set_id, bits ):
    print '{:>4}'.format( v ),
print