#!/usr/bin/python

import Image
from sys import argv

# lookup tables for the 3 different charsets
CharSetA =  {
    ' ':0, '!':1, '"':2, '#':3, '$':4, '%':5, '&':6, "'":7,
    '(':8, ')':9, '*':10, '+':11, ',':12, '-':13, '.':14, '/':15,
    '0':16, '1':17, '2':18, '3':19, '4':20, '5':21, '6':22, '7':23,
    '8':24, '9':25, ':':26, ';':27, '<':28, '=':29, '>':30, '?':31,
    '@':32, 'A':33, 'B':34, 'C':35, 'D':36, 'E':37, 'F':38, 'G':39,
    'H':40, 'I':41, 'J':42, 'K':43, 'L':44, 'M':45, 'N':46, 'O':47,
    'P':48, 'Q':49, 'R':50, 'S':51, 'T':52, 'U':53, 'V':54, 'W':55,
    'X':56, 'Y':57, 'Z':58, '[':59, '\':60, ']':61, '^':62, '_':63,
    '\x00':64, '\x01':65, '\x02':66, '\x03':67, '\x04':68, '\x05':69, '\x06':70, '\x07':71,
    '\x08':72, '\x09':73, '\x0A':74, '\x0B':75, '\x0C':76, '\x0D':77, '\x0E':78, '\x0F':79,
    '\x10':80, '\x11':81, '\x12':82, '\x13':83, '\x14':84, '\x15':85, '\x16':86, '\x17':87,
    '\x18':88, '\x19':89, '\x1A':90, '\x1B':91, '\x1C':92, '\x1D':93, '\x1E':94, '\x1F':95,
    'FNC3':96, 'FNC2':97, 'SHIFT':98, 'Code C':99, 'Code B':100, 'FNC4':101, 'FNC1':102, 'START A':103,
    'START B':104, 'START C':105, ' STOP':106
}

CharSetB = {
    ' ':0, '!':1, '"':2, '#':3, '$':4, '%':5, '&':6, "'":7,
    '(':8, ')':9, '*':10, '+':11, ',':12, '-':13, '.':14, '/':15,
    '0':16, '1':17, '2':18, '3':19, '4':20, '5':21, '6':22, '7':23,
    '8':24, '9':25, ':':26, ';':27, '<':28, '=':29, '>':30, '?':31,
    '@':32, 'A':33, 'B':34, 'C':35, 'D':36, 'E':37, 'F':38, 'G':39,
    'H':40, 'I':41, 'J':42, 'K':43, 'L':44, 'M':45, 'N':46, 'O':47,
    'P':48, 'Q':49, 'R':50, 'S':51, 'T':52, 'U':53, 'V':54, 'W':55,
    'X':56, 'Y':57, 'Z':58, '[':59, '\':60, ']':61, '^':62, '_':63,
    '' :64, 'a':65, 'b':66, 'c':67, 'd':68, 'e':69, 'f':70, 'g':71,
    'h':72, 'i':73, 'j':74, 'k':75, 'l':76, 'm':77, 'n':78, 'o':79,
    'p':80, 'q':81, 'r':82, 's':83, 't':84, 'u':85, 'v':86, 'w':87,
    'x':88, 'y':89, 'z':90, '{':91, '|':92, '}':93, '~':94, '\x7F':95,
    'FNC3':96, 'FNC2':97, 'SHIFT':98, 'Code C':99, 'FNC4':100, 'Code A':101, 'FNC1':102, 'START A':103,
    'START B':104, 'START C':105, ' STOP':106
}

CharSetC = {
    '00':0, '01':1, '02':2, '03':3, '04':4, '05':5, '06':6, '07':7,
    '08':8, '09':9, '10':10, '11':11, '12':12, '13':13, '14':14, '15':15,
    '16':16, '17':17, '18':18, '19':19, '20':20, '21':21, '22':22, '23':23,
    '24':24, '25':25, '26':26, '27':27, '28':28, '29':29, '30':30, '31':31,
    '32':32, '33':33, '34':34, '35':35, '36':36, '37':37, '38':38, '39':39,
    '40':40, '41':41, '42':42, '43':43, '44':44, '45':45, '46':46, '47':47,
    '48':48, '49':49, '50':50, '51':51, '52':52, '53':53, '54':54, '55':55,
    '56':56, '57':57, '58':58, '59':59, '60':60, '61':61, '62':62, '63':63,
    '64':64, '65':65, '66':66, '67':67, '68':68, '69':69, '70':70, '71':71,
    '72':72, '73':73, '74':74, '75':75, '76':76, '77':77, '78':78, '79':79,
    '80':80, '81':81, '82':82, '83':83, '84':84, '85':85, '86':86, '87':87,
    '88':88, '89':89, '90':90, '91':91, '92':92, '93':93, '94':94, '95':95,
    '96':96, '97':97, '98':98, '99':99, 'Code B':100, 'Code A':101, 'FNC1':102, 'START A':103,
    'START B':104, 'START C':105, ' STOP':106
}

# The barcode and the according number in the according char-set
ValueEncodings = {
    0:'11011001100',  1:'11001101100',  2:'11001100110',
    3:'10010011000',  4:'10010001100',  5:'10001001100',
    6:'10011001000',  7:'10011000100',  8:'10001100100',
    9:'11001001000', 10:'11001000100', 11:'11000100100',
    12:'10110011100', 13:'10011011100', 14:'10011001110',
    15:'10111001100', 16:'10011101100', 17:'10011100110',
    18:'11001110010', 19:'11001011100', 20:'11001001110',
    21:'11011100100', 22:'11001110100', 23:'11101101110',
    24:'11101001100', 25:'11100101100', 26:'11100100110',
    27:'11101100100', 28:'11100110100', 29:'11100110010',
    30:'11011011000', 31:'11011000110', 32:'11000110110',
    33:'10100011000', 34:'10001011000', 35:'10001000110',
    36:'10110001000', 37:'10001101000', 38:'10001100010',
    39:'11010001000', 40:'11000101000', 41:'11000100010',
    42:'10110111000', 43:'10110001110', 44:'10001101110',
    45:'10111011000', 46:'10111000110', 47:'10001110110',
    48:'11101110110', 49:'11010001110', 50:'11000101110',
    51:'11011101000', 52:'11011100010', 53:'11011101110',
    54:'11101011000', 55:'11101000110', 56:'11100010110',
    57:'11101101000', 58:'11101100010', 59:'11100011010',
    60:'11101111010', 61:'11001000010', 62:'11110001010',
    63:'10100110000', 64:'10100001100', 65:'10010110000',
    66:'10010000110', 67:'10000101100', 68:'10000100110',
    69:'10110010000', 70:'10110000100', 71:'10011010000',
    72:'10011000010', 73:'10000110100', 74:'10000110010',
    75:'11000010010', 76:'11001010000', 77:'11110111010',
    78:'11000010100', 79:'10001111010', 80:'10100111100',
    81:'10010111100', 82:'10010011110', 83:'10111100100',
    84:'10011110100', 85:'10011110010', 86:'11110100100',
    87:'11110010100', 88:'11110010010', 89:'11011011110',
    90:'11011110110', 91:'11110110110', 92:'10101111000',
    93:'10100011110', 94:'10001011110', 95:'10111101000',
    96:'10111100010', 97:'11110101000', 98:'11110100010',
    99:'10111011110',100:'10111101110',101:'11101011110',
    102:'11110101110',103:'11010000100',104:'11010010000',
    105:'11010011100',106:'11000111010'
}# '

# swap the dictionaries
def swap_dictionary(original_dict):
    # old version
#   return dict( [(v, k) for (k, v) in original_dict.iteritems()] )
    # refined version... with generator expressions...thx J
    return dict( (v, k) for (k, v) in original_dict.iteritems() )

# I found these encoding tables on the web...
# sadly the key:value pairs are the wrong way for my need
# so i swap them =)
CharSetA = swap_dictionary(CharSetA)
CharSetB = swap_dictionary(CharSetB)
CharSetC = swap_dictionary(CharSetC)
ValueEncodings = swap_dictionary(ValueEncodings)


# read in image
im_file = Image.open(argv[1])
im = im_file.getdata()
width = im.size[0]
height = im.size[1] / 2

# convert to 1 pixel high stripe in the middle of the image
cropped = im.crop((0,height,width,height+1))

# translate to 0's and 1's
code = ''
for pixel in cropped:
    try: # if is RGB picture
        pix = pixel[0]
    except: # if is greyscale picture
        pix = pixel
    if pix >200:
        pix = 0
    else:
        pix = 1
    code += str(pix)


# remove leading and trailing 0's
code = code.lstrip('0').rstrip('0')
   
   
# pop first 11 bits from the code
# these 11 bits stand for a char
def get_char(code):
    char = code[:11]
    code = code[11:]
    return char, code


out_buff = ""
# determine the encoding
first, code = get_char(code)
encoding = ValueEncodings[first]

if encoding == 103:
    charset = CharSetA
    out_buff += 'START A '
elif encoding == 104:
    charset = CharSetB
    out_buff += 'START B '
elif encoding == 105:
    charset = CharSetC
    out_buff += 'START C '
else:
    print "Encoding unknown"
    exit(0)


# decypher the message
while(len(code) >= 11):
    next_char, code = get_char(code)
    encoding_number = ValueEncodings[next_char]
    out_buff += charset[encoding_number]

# display the message
print out_buff