stackoverflow_2929404.py

#!/usr/bin/env python3.1

import timeit
from itertools import chain

def magic(f): return f
def more_magic(f): return f

@magic
def double_digits_holger8(x):
	m = (x * 0x0101010101010101 & 0x8040201008040201) * 0x0102040810204081
	return ((m >> 49) & 0x5555) | ((m >> 48) & 0xAAAA)

@more_magic
def double_digits_binmag16(x):
	x = (x | x << 8) & 0x00FF00FF;
	x = (x | x << 4) & 0x0F0F0F0F;
	x = (x | x << 2) & 0x33333333;
	x = (x | x << 1) & 0x55555555;
	return x | x << 1

def double_digits_mark(x):
	return int(bin(x)[2:], 4)*3

def double_digits_max(x):
	return int(bin(x)[2:].replace("0","00").replace("1","11"),2)

def double_digits_elegant(x):
	X = bin(x)[2:]
	return int(''.join([''.join(i) for i in zip(X,X)]), 2)

def double_digits_xavier(x):
	X = bin(x)[2:]
	return int(''.join(chain(*zip(X, X))), 2)

def double_digits_jim16(x):
	y = 0
	i = 15
	while i >= 0:
		if (1 << i) & x:
			y |= 3
		y <<= 2
		i -= 1
	return y

def double_digits_peter(n):
    result = 0
    power = 1
    while n > 0:
        if n%2==1:
            result += 3*power
        power *= 4
        n //= 2
    return result

def double_digits_phimuemue_nolog(x):
    numdigits = x.bit_length()
    result = 1 << (numdigits*2)
    for i in range(numdigits, -1, -1):
        mask = 1 << i
        if (x & mask > 0):
            rmask = 0b11 << (2*i)
            result = result | rmask
    return result

def double_digits_control(i):
	pass

def test(name):
	which = globals()[name]
	for i in range(256):
		which(i)

		
timeit.main(['-s', 'from __main__ import test;', 'test("double_digits_phimuemue_nolog")'])