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def reverse_bits(b, length=8):
    r = 0
    for _ in range(length):
        r = (r << 1) | (b & 1)
        b >>= 1
    return r

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BASIC_TOKENS = {
    128: " FOR ",     # 0x80
    129: " GO ",      # 0x81
    130: " REM ",     # 0x82
    131: "'",         # 0x83
    132: " ELSE ",    # 0x84
    133: " IF ",      # 0x85
...

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def block2ascii(bit_list):
    for block in iter_steps(bit_list, steps=8):
        byte_no = bits2ASCII(block)

        if byte_no in BASIC_TOKENS:
            character = BASIC_TOKENS[byte_no]
        else:
            character = chr(byte_no)

        print "%s %4s %3s %s" % (
            list2str(block), hex(byte_no), byte_no, repr(character)
        )

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...
11100001 0x87 135 ' PRINT '
00000100 0x20  32 ' '
10010010 0x49  73 'I'
11011100 0x3b  59 ';'
01000100 0x22  34 '"'
00010010 0x48  72 'H'
10100010 0x45  69 'E'
00110010 0x4c  76 'L'
00110010 0x4c  76 'L'
11110010 0x4f  79 'O'
00000100 0x20  32 ' '
11101010 0x57  87 'W'
11110010 0x4f  79 'O'
01001010 0x52  82 'R'
00110010 0x4c  76 'L'
00100010 0x44  68 'D'
10000100 0x21  33 '!'
01000100 0x22  34 '"'
00000000  0x0   0 '\x00'
...

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    TEST_STR=(
        "00010010" # 0x48  72 'H'
        "10100010" # 0x45  69 'E'
        "00110010" # 0x4c  76 'L'
        "00110010" # 0x4c  76 'L'
        "11110010" # 0x4f  79 'O'
        "00000100" # 0x20  32 ' '
        "11101010" # 0x57  87 'W'
        "11110010" # 0x4f  79 'O'
        "01001010" # 0x52  82 'R'
        "00110010" # 0x4c  76 'L'
        "00100010" # 0x44  68 'D'
        "10000100" # 0x21  33 '!'
    )# 000100101010001000110010001100101111001000000100111010101111001001001010001100100010001010000100
    test_start = get_start_pos_iter_window(bit_list, TEST_STR)
    print "*** Test String found at:", test_start

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...
  sentinel = c_ubyte()
  i_bits = iter(bits)
  for bit in i_bits:
    sentinel.value <<= 1
    sentinel.value |= bit
    if sentinel.value == 42: # ?? nicht spec-konform
      break
...[/quote]
Hab mir den code nochmal genauer angesehen.

Kann es sein, das im Grunde hier in dem Teil im Prinzip das selbe gemacht wird, wie bei mir? Also das man bit für bit durchgeht und ein bestimmtes Muster zu suchen? In diesem Fall halt [b]START_LEADER = "10101010"[/b]

Wobei ich mir nun überlegt habe, das gerade [b]10101010[/b] ziemlich doof ist. Denn die genau Position kann in diesem Fall doch sehr leicht um 2 Bits vor/zurück verschoben sein und doch passt es.

Bei http://www.onastick.clara.net/cosio.htm steht auch was von einem sync byte:
[b]1. A leader byte - $55
2. A sync byte - $3C[/b]

Kann es sein, das man besser das suchen sollte?

EDIT: Kann es sein, das 0x3C das ist: [b]00111100[/b] ?
Das würde auch mehr Sinn machen!

Code: Alles auswählen

def goto_next_block(bit_list, debug=False):
    """
    >>> bits = (
    ... "10101010" # 0x55 leader byte
    ... "00111100" # 0x3C sync byte
    ... "00010010" # 0x48 'H'
    ... )
    >>> bit_list = [int(i) for i in bits]
    >>> bit_list = goto_next_block(bit_list)
    >>> bit_list
    [0, 0, 0, 1, 0, 0, 1, 0]

    more bits inserted:
    >>> bits = ("1010" # inserted
    ... "101010100011110000010010")
    >>> goto_next_block([int(i) for i in bits])
    [0, 0, 0, 1, 0, 0, 1, 0]

    no complete leader byte
    >>> bits = ("1010" # incomplete
    ... "0011110000010010")
    >>> goto_next_block([int(i) for i in bits])
    [0, 0, 0, 1, 0, 0, 1, 0]
    """
    end = get_last_pos_iter_steps(bit_list, LEADER_BYTE)
    if not end:
        if debug:
            print "INFO: leader byte block end not found."
    else:
        if debug:
            print "leader byte block end found at:", end
        bit_list = bit_list[end:]

    sync_pos = get_start_pos_iter_window(bit_list, SYNC_BYTE)
    if sync_pos is None:
        if debug:
            print "ERROR: Sync byte '%s' not found!" % SYNC_BYTE
        sys.exit(-1)
    if debug:
        print "Sync byte '%s' found at position: %i" % (SYNC_BYTE, sync_pos)

    # Cut until sync byte
    cut_pos = sync_pos + len(SYNC_BYTE)
    bit_list = bit_list[cut_pos:]

    return bit_list

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>>> bin(0x3c)
'0b111100'

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 "{:08b}".format(0x3c)

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In [7]: '{0:08b}'.format(0x3c)
Out[7]: '00111100'

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def iter_tokenized_lines(bytestream):
    while True:
        next_line_pointer = bytestream.get_word()
        if next_line_pointer == 0:
            break
        line_number = bytestream.get_word()
        tokenized_line = bytestream.get_until('\x00')
        yield (line_number, tokenized_line)

Code: Alles auswählen

def samples2bits(samples, framerate, frame_count, even_odd):
    in_positive = even_odd
    in_negative = not even_odd
    toggle_count = 0 # Counter for detect a complete cycle
    previous_frame_no = 0
    bit_count = 0

    window_values = collections.deque(maxlen=MIN_TOGGLE_COUNT)
    for frame_no, value in samples:
        window_values.append(value)
        if len(window_values) >= MIN_TOGGLE_COUNT:
            positive_count, negative_count = count_sign(window_values)

            # print window_values, positive_count, negative_count
            if not in_positive and positive_count == MIN_TOGGLE_COUNT and negative_count == 0:
                # go into a positive sinus area
                in_positive = True
                in_negative = False
                toggle_count += 1
            elif not in_negative and negative_count == MIN_TOGGLE_COUNT and positive_count == 0:
                # go into a negative sinus area
                in_negative = True
                in_positive = False
                toggle_count += 1

            if toggle_count >= 2:
                # a single sinus cycle complete
                toggle_count = 0

                frame_count = frame_no - previous_frame_no
                hz = framerate / frame_count

                dst_one = abs(ONE_HZ - hz)
                dst_nul = abs(NUL_HZ - hz)
                if dst_one < dst_nul:
                    bit_count += 1
                    yield 1
                else:
                    bit_count += 1
                    yield 0

                previous_frame_no = frame_no