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ccitt.py
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ccitt.py
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#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
ccitt.py
TODO
http://tools.ietf.org/pdf/rfc804.pdf
http://code.google.com/p/origami-pdf/source/browse/lib/origami/filters/ccitt.rb
"""
__author__ = 'Binjo'
__version__ = '0.1'
__date__ = '2012-04-08 14:30:05'
class BitWriterException(Exception):
pass
class BitWriter(object):
"""
"""
def __init__(self, ):
"""
"""
self._data = ''
self._last_byte = None
self._bit_ptr = 0
@property
def data(self):
"""
"""
return self._data
def write(self, data, length):
"""
"""
if not ( length >= 0 and (1 << length) > data ):
raise BitWriterException, "Invalid data length"
if length == 8 and not self._last_byte and self._bit_ptr == 0:
self._data += chr(data)
return
while length > 0:
if length >= 8 - self._bit_ptr:
length -= 8 - self._bit_ptr
if not self._last_byte:
self._last_byte = 0
self._last_byte |= (data >> length) & ((1 << (8 - self._bit_ptr)) - 1)
data &= (1 << length) - 1
self._data += chr(self._last_byte)
self._last_byte = None
self._bit_ptr = 0
else:
if not self._last_byte:
self._last_byte = 0
self._last_byte |= (data & ((1 << length) - 1)) << (8 - self._bit_ptr - length)
self._bit_ptr += length
if self._bit_ptr == 8:
self._data += chr(self._last_byte)
self._last_byte = None
self._bit_ptr = 0
length = 0
class BitReaderException(Exception):
pass
class BitReader(object):
"""
"""
def __init__(self, data):
"""
"""
self._data = data
self._byte_ptr, self._bit_ptr = 0, 0
def reset(self):
"""
"""
self._byte_ptr, self._bit_ptr = 0, 0
@property
def eod_p(self):
"""
"""
return self._byte_ptr >= len(self._data)
@property
def pos(self):
"""
"""
return (self._byte_ptr << 3) + self._bit_ptr
@property
def size(self):
"""
"""
return len(self._data) << 3
@pos.setter
def pos(self, bits):
"""
"""
if bits > self.size:
raise BitReaderException, "Pointer position out of data"
pbyte = bits >> 3
pbit = bits - (pbyte <<3)
self._byte_ptr, self._bit_ptr = pbyte, pbit
def peek(self, length):
"""
"""
if length <= 0:
raise BitReaderException, "Invalid read length"
elif ( self.pos + length ) > self.size:
raise BitReaderException, "Insufficient data"
n = 0
byte_ptr, bit_ptr = self._byte_ptr, self._bit_ptr
while length > 0:
byte = ord( self._data[byte_ptr] )
if length > 8 - bit_ptr:
length -= 8 - bit_ptr
n |= ( byte & ((1 << (8 - bit_ptr)) - 1) ) << length
byte_ptr += 1
bit_ptr = 0
else:
n |= (byte >> (8 - bit_ptr - length)) & ((1 << length) - 1)
length = 0
return n
def read(self, length):
"""
"""
n = self.peek(length)
self.pos += length
return n
def codeword(bits):
"""return tuple rather than list, since list is not hashable...
"""
return ( int(bits, 2), len(bits) )
class CCITTFax(object):
"""
"""
EOL = codeword('000000000001')
RTC = codeword('000000000001' * 6)
WHITE_TERMINAL_ENCODE_TABLE = {
0 : codeword('00110101'),
1 : codeword('000111'),
2 : codeword('0111'),
3 : codeword('1000'),
4 : codeword('1011'),
5 : codeword('1100'),
6 : codeword('1110'),
7 : codeword('1111'),
8 : codeword('10011'),
9 : codeword('10100'),
10 : codeword('00111'),
11 : codeword('01000'),
12 : codeword('001000'),
13 : codeword('000011'),
14 : codeword('110100'),
15 : codeword('110101'),
16 : codeword('101010'),
17 : codeword('101011'),
18 : codeword('0100111'),
19 : codeword('0001100'),
20 : codeword('0001000'),
21 : codeword('0010111'),
22 : codeword('0000011'),
23 : codeword('0000100'),
24 : codeword('0101000'),
25 : codeword('0101011'),
26 : codeword('0010011'),
27 : codeword('0100100'),
28 : codeword('0011000'),
29 : codeword('00000010'),
30 : codeword('00000011'),
31 : codeword('00011010'),
32 : codeword('00011011'),
33 : codeword('00010010'),
34 : codeword('00010011'),
35 : codeword('00010100'),
36 : codeword('00010101'),
37 : codeword('00010110'),
38 : codeword('00010111'),
39 : codeword('00101000'),
40 : codeword('00101001'),
41 : codeword('00101010'),
42 : codeword('00101011'),
43 : codeword('00101100'),
44 : codeword('00101101'),
45 : codeword('00000100'),
46 : codeword('00000101'),
47 : codeword('00001010'),
48 : codeword('00001011'),
49 : codeword('01010010'),
50 : codeword('01010011'),
51 : codeword('01010100'),
52 : codeword('01010101'),
53 : codeword('00100100'),
54 : codeword('00100101'),
55 : codeword('01011000'),
56 : codeword('01011001'),
57 : codeword('01011010'),
58 : codeword('01011011'),
59 : codeword('01001010'),
60 : codeword('01001011'),
61 : codeword('00110010'),
62 : codeword('00110011'),
63 : codeword('00110100')
}
WHITE_TERMINAL_DECODE_TABLE = dict( (v, k) for k, v in WHITE_TERMINAL_ENCODE_TABLE.iteritems() )
BLACK_TERMINAL_ENCODE_TABLE = {
0 : codeword('0000110111'),
1 : codeword('010'),
2 : codeword('11'),
3 : codeword('10'),
4 : codeword('011'),
5 : codeword('0011'),
6 : codeword('0010'),
7 : codeword('00011'),
8 : codeword('000101'),
9 : codeword('000100'),
10 : codeword('0000100'),
11 : codeword('0000101'),
12 : codeword('0000111'),
13 : codeword('00000100'),
14 : codeword('00000111'),
15 : codeword('000011000'),
16 : codeword('0000010111'),
17 : codeword('0000011000'),
18 : codeword('0000001000'),
19 : codeword('00001100111'),
20 : codeword('00001101000'),
21 : codeword('00001101100'),
22 : codeword('00000110111'),
23 : codeword('00000101000'),
24 : codeword('00000010111'),
25 : codeword('00000011000'),
26 : codeword('000011001010'),
27 : codeword('000011001011'),
28 : codeword('000011001100'),
29 : codeword('000011001101'),
30 : codeword('000001101000'),
31 : codeword('000001101001'),
32 : codeword('000001101010'),
33 : codeword('000001101011'),
34 : codeword('000011010010'),
35 : codeword('000011010011'),
36 : codeword('000011010100'),
37 : codeword('000011010101'),
38 : codeword('000011010110'),
39 : codeword('000011010111'),
40 : codeword('000001101100'),
41 : codeword('000001101101'),
42 : codeword('000011011010'),
43 : codeword('000011011011'),
44 : codeword('000001010100'),
45 : codeword('000001010101'),
46 : codeword('000001010110'),
47 : codeword('000001010111'),
48 : codeword('000001100100'),
49 : codeword('000001100101'),
50 : codeword('000001010010'),
51 : codeword('000001010011'),
52 : codeword('000000100100'),
53 : codeword('000000110111'),
54 : codeword('000000111000'),
55 : codeword('000000100111'),
56 : codeword('000000101000'),
57 : codeword('000001011000'),
58 : codeword('000001011001'),
59 : codeword('000000101011'),
60 : codeword('000000101100'),
61 : codeword('000001011010'),
62 : codeword('000001100110'),
63 : codeword('000001100111')
}
BLACK_TERMINAL_DECODE_TABLE = dict( (v, k) for k, v in BLACK_TERMINAL_ENCODE_TABLE.iteritems() )
WHITE_CONFIGURATION_ENCODE_TABLE = {
64 : codeword('11011'),
128 : codeword('10010'),
192 : codeword('010111'),
256 : codeword('0110111'),
320 : codeword('00110110'),
384 : codeword('00110111'),
448 : codeword('01100100'),
512 : codeword('01100101'),
576 : codeword('01101000'),
640 : codeword('01100111'),
704 : codeword('011001100'),
768 : codeword('011001101'),
832 : codeword('011010010'),
896 : codeword('011010011'),
960 : codeword('011010100'),
1024 : codeword('011010101'),
1088 : codeword('011010110'),
1152 : codeword('011010111'),
1216 : codeword('011011000'),
1280 : codeword('011011001'),
1344 : codeword('011011010'),
1408 : codeword('011011011'),
1472 : codeword('010011000'),
1536 : codeword('010011001'),
1600 : codeword('010011010'),
1664 : codeword('011000'),
1728 : codeword('010011011'),
1792 : codeword('00000001000'),
1856 : codeword('00000001100'),
1920 : codeword('00000001001'),
1984 : codeword('000000010010'),
2048 : codeword('000000010011'),
2112 : codeword('000000010100'),
2176 : codeword('000000010101'),
2240 : codeword('000000010110'),
2340 : codeword('000000010111'),
2368 : codeword('000000011100'),
2432 : codeword('000000011101'),
2496 : codeword('000000011110'),
2560 : codeword('000000011111')
}
WHITE_CONFIGURATION_DECODE_TABLE = dict( (v, k) for k, v in WHITE_CONFIGURATION_ENCODE_TABLE.iteritems() )
BLACK_CONFIGURATION_ENCODE_TABLE = {
64 : codeword('0000001111'),
128 : codeword('000011001000'),
192 : codeword('000011001001'),
256 : codeword('000001011011'),
320 : codeword('000000110011'),
384 : codeword('000000110100'),
448 : codeword('000000110101'),
512 : codeword('0000001101100'),
576 : codeword('0000001101101'),
640 : codeword('0000001001010'),
704 : codeword('0000001001011'),
768 : codeword('0000001001100'),
832 : codeword('0000001001101'),
896 : codeword('0000001110010'),
960 : codeword('0000001110011'),
1024 : codeword('0000001110100'),
1088 : codeword('0000001110101'),
1152 : codeword('0000001110110'),
1216 : codeword('0000001110111'),
1280 : codeword('0000001010010'),
1344 : codeword('0000001010011'),
1408 : codeword('0000001010100'),
1472 : codeword('0000001010101'),
1536 : codeword('0000001011010'),
1600 : codeword('0000001011011'),
1664 : codeword('0000001100100'),
1728 : codeword('0000001100101'),
1792 : codeword('00000001000'),
1856 : codeword('00000001100'),
1920 : codeword('00000001001'),
1984 : codeword('000000010010'),
2048 : codeword('000000010011'),
2112 : codeword('000000010100'),
2176 : codeword('000000010101'),
2240 : codeword('000000010110'),
2340 : codeword('000000010111'),
2368 : codeword('000000011100'),
2432 : codeword('000000011101'),
2496 : codeword('000000011110'),
2560 : codeword('000000011111')
}
BLACK_CONFIGURATION_DECODE_TABLE = dict( (v, k) for k, v in BLACK_CONFIGURATION_ENCODE_TABLE.iteritems() )
def __init__(self, ):
"""
"""
self._decoded = []
def decode(self, stream, k = 0, eol = False, byteAlign = False, columns = 1728, rows = 0, eob = True, blackIs1 = False, damagedRowsBeforeError = 0):
"""
"""
# FIXME seems not stick to the spec? default is false, but if not set as true, it won't decode 6cc2a162e08836f7d50d461a9fc136fe correctly
byteAlign = True
if blackIs1:
white, black = 0,1
else:
white, black = 1,0
bitr = BitReader( stream )
bitw = BitWriter()
while not ( bitr.eod_p or rows == 0 ):
current_color = white
if byteAlign and bitr.pos % 8 != 0:
bitr.pos += 8 - (bitr.pos % 8)
if eob and bitr.peek(self.RTC[1]) == self.RTC[0]:
bitr.pos += RTC[1]
break
if bitr.peek(self.EOL[1]) != self.EOL[0]:
if eol:
raise Exception, "No end-of-line pattern found (at bit pos %d/%d)" % (bitr.pos, bitr.size)
else:
bitr.pos += self.EOL[1]
line_length = 0
while line_length < columns:
if current_color == white:
bit_length = self.get_white_bits(bitr)
else:
bit_length = self.get_black_bits(bitr)
if bit_length == None:
raise Exception, "Unfinished line (at bit pos %d/%d), %s" % (bitr.pos, bitr.size, bitw.data)
line_length += bit_length
if line_length > columns:
raise Exception, "Line is too long (at bit pos %d/%d)" % (bitr.pos, bitr.size)
bitw.write( (current_color << bit_length) - current_color, bit_length )
current_color ^= 1
rows -= 1
return bitw.data
def get_white_bits(self, bitr):
"""
"""
return self.get_color_bits( bitr, self.WHITE_CONFIGURATION_DECODE_TABLE, self.WHITE_TERMINAL_DECODE_TABLE )
def get_black_bits(self, bitr):
"""
"""
return self.get_color_bits( bitr, self.BLACK_CONFIGURATION_DECODE_TABLE, self.BLACK_TERMINAL_DECODE_TABLE )
def get_color_bits(self, bitr, config_words, term_words):
"""
"""
bits = 0
check_conf = True
while check_conf:
check_conf = False
for i in xrange(2, 14):
codeword = bitr.peek(i)
config_value = config_words.get((codeword, i), None)
if config_value is not None:
bitr.pos += i
bits += config_value
if config_value == 2560:
check_conf = True
break
for i in xrange(2, 14):
codeword = bitr.peek(i)
term_value = term_words.get((codeword, i), None)
if term_value is not None:
bitr.pos += i
bits += term_value
return bits
return None