util.py

import sys
import binascii
import re


# The standard (IEEE 802) format for printing MAC-48 addresses
# in human-friendly form is six groups of two hexadecimal digits,
# separated by "-" hyphens or ":" colons. In order to extract
# this from input by REGEX_HEX12, first remove hyphens/colons.
REGEX_HEX12 = re.compile('^([0-9A-F]{12})$')


def normalize_address(address, ignore=':-'):
    """
    Normalize given address in uppercase mac-address with colons.
    Returns given address formatted like 'DE:AD:BE:EF:01:02'
    or an empty string if the given address doesn't match.
    """
    address = address.strip().upper()
    for c in ignore:
        address = address.replace(c, '')
    m = REGEX_HEX12.match(address)
    if m:
        address = m.group(0)
        return ':'.join(address[i:i + 2] for i in range(0, 12, 2))
    return ''


def bytes_to_uint32_le(bytes):
    return  (int(bytes[3], 16) << 24) | (int(bytes[2], 16) << 16) | (int(bytes[1], 16) <<  8) | (int(bytes[0], 16) <<  0)


def uint32_to_bytes_le(uint32):
    return [(uint32 >> 0)  & 0xff, 
            (uint32 >> 8)  & 0xff, 
            (uint32 >> 16) & 0xff, 
            (uint32 >> 24) & 0xff]


def uint16_to_bytes_le(value):
    return [(value >> 0 & 0xFF),
            (value >> 8 & 0xFF)]


def zero_pad_array_le(data, padsize):
    for i in range(0, padsize):
        data.insert(0, 0)


def array_to_hex_string(arr):
    hex_str = ""
    for val in arr:
        if val > 255:
            raise Exception("Value is greater than it is possible to represent with one byte")
        hex_str += "%02x" % val
    return hex_str


def crc32_unsigned(bytestring):
    return binascii.crc32(bytestring) % (1 << 32)


def mac_string_to_uint(mac):
    parts = list(re.match('(..):(..):(..):(..):(..):(..)', mac).groups())
    ints = map(lambda x: int(x, 16), parts)
    res = 0
    for i in range(0, len(ints)):
        res += (ints[len(ints)-1 - i] << 8*i)
    return res


def uint_to_mac_string(mac):
    ints = [0, 0, 0, 0, 0, 0]
    for i in range(0, len(ints)):
        ints[len(ints)-1 - i] = (mac >> 8*i) & 0xff
    return ':'.join(map(lambda x: '{:02x}'.format(x).upper(), ints))


def print_progress(iteration, total, prefix = '', suffix = '', decimals = 1, barLength = 100):
    """
    Print a nice console progress bar.
    Call in a loop to provide a console progress bar.
    @params:
        iteration   - Required  : current iteration (Int)
        total       - Required  : total iterations (Int)
        prefix      - Optional  : prefix string (Str)
        suffix      - Optional  : suffix string (Str)
        decimals    - Optional  : positive number of decimals in percent complete (Int)
        barLength   - Optional  : character length of bar (Int)
    """
    formatStr       = "{0:." + str(decimals) + "f}"
    percents        = formatStr.format(100 * (iteration / float(total)))
    filledLength    = int(round(barLength * iteration / float(total)))
    bar             = 'x' * filledLength + '-' * (barLength - filledLength)
    sys.stdout.write('\r%s |%s| %s%s %s (%d of %d bytes)' % (prefix, bar, percents, '%', suffix, iteration, total)),
    if iteration == total:
        sys.stdout.write('\n')
    sys.stdout.flush()