def __init__(self, data):
self.huffval = create_array([], 4)
self.valptr = create_array([], 4)
self.mincode = create_array([], 4)
self.maxcode = create_array([], 4)
self.zz = create_array(0, 64)
self.qnt = create_array(0, 4, 64)
self.data = EmbedData(data)
self.size = len(self.data)
self.ri = 0
while True:
if self.get_byte() == 255:
b = self.get_byte()
if b == 192:
self.sof0()
elif b == 196:
self.dht()
elif b == 219:
self.dqt()
elif b == 217 or b == 218:
break
elif b in self.APP:
self.skip_variable()
elif b == self.DRI:
self.dri()
def compress(self, embedded_data=None, password='******'):
self.embedded_data = EmbedData(
embedded_data) if embedded_data else None
self.password = password
self.write_headers()
self.write_compressed_data()
self.write_eoi()
self.out.flush()
def __init__(self, data):
self.huffval = create_array([], 4)
self.valptr = create_array([], 4)
self.mincode = create_array([], 4)
self.maxcode = create_array([], 4)
self.zz = create_array(0, 64)
self.qnt = create_array(0, 4, 64)
self.data = EmbedData(data)
self.size = len(self.data)
self.ri = 0
while True:
if self.get_byte() == 255:
b = self.get_byte()
if b == 192:
self.sof0()
elif b == 196:
self.dht()
elif b == 219:
self.dqt()
elif b == 217 or b == 218:
break
elif b in self.APP:
self.skip_variable()
elif b == self.DRI:
self.dri()
def compress(self, embedded_data=None, password='******'):
self.embedded_data = EmbedData(embedded_data) if embedded_data else None
self.password = password
self.write_headers()
self.write_compressed_data()
self.write_eoi()
self.out.flush()
class JpegEncoder(object):
def __init__(self, image, quality, out, comment, ais):
self.quality = quality
self.jpeg_obj = JpegInfo(image, comment)
self.image_width, self.image_height = image.size
self.out = out
self.dct = DCT(self.quality)
self.huf = Huffman(*image.size)
self.hasais = ais
self.k_matrix = -1
def compress(self, embedded_data=None, password='******'):
self.embedded_data = EmbedData(
embedded_data) if embedded_data else None
self.password = password
self.write_headers()
self.write_compressed_data()
self.write_eoi()
self.out.flush()
def get_quality(self):
return self.quality
def set_quality(self, quality):
self.quality = quality
self.dct = DCT(quality)
def write_array(self, data):
length = ((data[2] & 0xff) << 8) + (data[3] & 0xff) + 2
self.out.write(bytearray(data[:length]))
def write_marker(self, data):
self.out.write(bytearray(data[:2]))
def write_eoi(self):
EOI = [0xff, 0xD9]
self.write_marker(EOI)
def write_headers(self):
SOI = [0xff, 0xD8]
self.write_marker(SOI)
JFIF = [
0xff, 0xe0, 0x00, 0x10, 0x4a, 0x46, 0x49, 0x46, 0x00, 0x01, 0x01,
0x01, 0x00, 0x60, 0x00, 0x60, 0x00, 0x00
]
self.write_array(JFIF)
comment = self.jpeg_obj.get_comment()
if comment:
length = len(comment) + 2
COM = [0xff, 0xfe, length >> 8 & 0xff, length & 0xff]
COM.extend(comment)
self.write_array(COM)
DQT = [0xff, 0xdb, 0x00, 0x84]
for k in range(2):
DQT.append(k)
DQT.extend([
self.dct.quantum[k][JPEG_NATURAL_ORDER[i]] for i in range(64)
])
self.write_array(DQT)
SOF = [
0xff, 0xc0, 0x00, 0x11, self.jpeg_obj.precision,
self.jpeg_obj.image_height >> 8 & 0xff,
self.jpeg_obj.image_height & 0xff,
self.jpeg_obj.image_width >> 8 & 0xff,
self.jpeg_obj.image_width & 0xff, self.jpeg_obj.comp_num
]
for i in range(self.jpeg_obj.comp_num):
SOF.append(self.jpeg_obj.com_id[i])
SOF.append(
eight_byte(self.jpeg_obj.hsamp_factor[i],
self.jpeg_obj.vsamp_factor[i]))
SOF.append(self.jpeg_obj.qtable_number[i])
self.write_array(SOF)
DHT = [0xff, 0xc4, 0, 0]
for i in range(4):
DHT.extend(self.huf.BITS[i])
DHT.extend(self.huf.VAL[i])
DHT[2] = len(DHT) - 2 >> 8 & 0xff
DHT[3] = len(DHT) - 2 & 0xff
self.write_array(DHT)
SOS = [0] * 14
SOS = [0xff, 0xda, 0x00, 0x0c, self.jpeg_obj.comp_num]
for i in range(self.jpeg_obj.comp_num):
SOS.append(self.jpeg_obj.com_id[i])
SOS.append(
eight_byte(self.jpeg_obj.dctable_number[i],
self.jpeg_obj.actable_number[i]))
SOS.append(self.jpeg_obj.ss)
SOS.append(self.jpeg_obj.se)
SOS.append(eight_byte(self.jpeg_obj.ah, self.jpeg_obj.al))
self.write_array(SOS)
def _get_coeff(self):
dct_array1 = create_array(0.0, 8, 8)
dct_array2 = create_array(0.0, 8, 8)
dct_array3 = create_array(0, 64)
coeff = []
for r in range(min(self.jpeg_obj.block_height)):
for c in range(min(self.jpeg_obj.block_width)):
xpos = c * 8
ypos = r * 8
for comp in range(self.jpeg_obj.comp_num):
indata = self.jpeg_obj.components[comp]
maxa = self.image_height / 2 * self.jpeg_obj.vsamp_factor[
comp] - 1
maxb = self.image_width / 2 * self.jpeg_obj.hsamp_factor[
comp] - 1
for i in range(self.jpeg_obj.vsamp_factor[comp]):
for j in range(self.jpeg_obj.hsamp_factor[comp]):
ia = ypos * self.jpeg_obj.vsamp_factor[comp] + i * 8
ib = xpos * self.jpeg_obj.hsamp_factor[comp] + j * 8
for a in range(8):
for b in range(8):
dct_array1[a][b] = indata[min(
ia + a, maxa)][min(ib + b, maxb)]
dct_array2 = self.dct.forward_dct(dct_array1)
dct_array3 = self.dct.quantize_block(
dct_array2, self.jpeg_obj.qtable_number[comp])
coeff.extend(dct_array3[:64])
return coeff
def write_compressed_data(self):
last_dc_value = create_array(0, self.jpeg_obj.comp_num)
zero_array = create_array(0, 64)
width, height = 0, 0
min_block_width = min(self.jpeg_obj.block_width)
min_block_height = min(self.jpeg_obj.block_height)
logger.info('DCT/quantisation starts')
logger.info('%d x %d' % (self.image_width, self.image_height))
coeff = self._get_coeff() #量化后的系数,是整数
coeff_count = len(coeff)
#导出未处理的QDCT
if self.hasais:
filename = 'unpro_ais.json'
else:
filename = 'unpro.json'
with open(filename, 'w') as f_unprocess:
json.dump(coeff, f_unprocess)
#AIS处理
if self.hasais:
size_secret = self.embedded_data.len
ais = Ais(coeff, size_secret) #coeff被修改
ais.statistic()
self.k_matrix = ais.fix()
with open('aised.json', 'w') as f_aised:
json.dump(coeff, f_aised)
#嵌入——>再统计嵌入后的数据,决定是否继续做AIS处理
logger.info('got %d DCT AC/DC coefficients' % coeff_count)
_changed, _embedded, _examined, _expected, _one, _large, _thrown, _zero = 0, 0, 0, 0, 0, 0, 0, 0
shuffled_index = 0
for i, cc in enumerate(coeff):
if i % 64 == 0:
continue
if cc == 1 or cc == -1:
_one += 1
elif cc == 0:
_zero += 1
_large = coeff_count - _zero - _one - coeff_count / 64 #有效系数的个数
_expected = _large + int(0.49 * _one) #预期容量,shrinkage效应无法确定
logger.info('one=%d' % _one)
logger.info('large=%d' % _large)
logger.info('\nexpected capacity: %d bits\n' % _expected)
logger.info('expected capacity with')
for i in range(1, 8):
n = (1 << i) - 1 #n=2^i-1
changed = _large - _large % (n + 1)
changed = (changed + _one + _one / 2 - _one / (n + 1)) / (n + 1)
usable = (_expected * i / n - _expected * i / n % n) / 8
if usable == 0:
break
logger.info(
'%s code: %d bytes (efficiency: %d.%d bits per change)' %
('default' if i == 1 else '(1, %d, %d)' % (n, i), usable,
usable * 8 / changed, usable * 80 / changed % 10))
#shuffles all coefficients using a permutation,使用排列对系数进行混洗
if self.embedded_data is not None:
logger.info('permutation starts')
random = F5Random(self.password)
permutation = Permutation(coeff_count, random)
next_bit_to_embed = 0
byte_to_embed = len(self.embedded_data)
available_bits_to_embed = 0
logger.info('Embedding of %d bits (%d+4 bytes)' %
(byte_to_embed * 8 + 32, byte_to_embed))
if byte_to_embed > 0x007fffff:
byte_to_embed = 0x007ffff
for i in range(1, 8):
self.n = (1 << i) - 1
usable = (_expected * i / self.n -
_expected * i / self.n % self.n) / 8
if usable < byte_to_embed + 4:
break
#确定(1,n,k)
if self.k_matrix < 0:
k = i - 1
else:
k = self.k_matrix
self.n = (1 << k) - 1
if self.n == 0:
logger.info('using default code, file will not fit')
self.n = 1
elif self.n == 1:
logger.info('using default code')
else:
logger.info('using (1, %d, %d) code' % (self.n, k))
byte_to_embed |= k << 24
byte_to_embed ^= random.get_next_byte()
byte_to_embed ^= random.get_next_byte() << 8
byte_to_embed ^= random.get_next_byte() << 16
byte_to_embed ^= random.get_next_byte() << 24
next_bit_to_embed = byte_to_embed & 1
byte_to_embed >>= 1
available_bits_to_embed = 31
_embedded += 1
for i, shuffled_index in enumerate(permutation.shuffled):
if shuffled_index % 64 == 0 or coeff[shuffled_index] == 0:
continue
cc = coeff[shuffled_index]
_examined += 1
if cc > 0 and (cc & 1) != next_bit_to_embed:
coeff[shuffled_index] -= 1
_changed += 1
elif cc < 0 and (cc & 1) == next_bit_to_embed:
coeff[shuffled_index] += 1
_changed += 1
if coeff[shuffled_index] != 0:
if available_bits_to_embed == 0:
if self.n > 1 or not self.embedded_data.available():
break
byte_to_embed = self.embedded_data.read()
byte_to_embed ^= random.get_next_byte()
available_bits_to_embed = 8
next_bit_to_embed = byte_to_embed & 1
byte_to_embed >>= 1
available_bits_to_embed -= 1
_embedded += 1
else:
_thrown += 1
if self.n > 1:
try:
is_last_byte = False
filtered_index = FilteredCollection(
permutation.shuffled[i + 1:],
lambda index: index % 64 and coeff[index])
while not is_last_byte:
k_bits_to_embed = 0
for i in range(k):
if available_bits_to_embed == 0:
if not self.embedded_data.available():
is_last_byte = True
break
byte_to_embed = self.embedded_data.read()
byte_to_embed ^= random.get_next_byte()
available_bits_to_embed = 8
next_bit_to_embed = byte_to_embed & 1
byte_to_embed >>= 1
available_bits_to_embed -= 1
k_bits_to_embed |= next_bit_to_embed << i
_embedded += 1
code_word = filtered_index.offer(self.n)
while True:
vhash = 0
for i, index in enumerate(code_word):
if coeff[index] > 0:
extracted_bit = coeff[index] & 1
else:
extracted_bit = 1 - (coeff[index] & 1)
if extracted_bit == 1:
vhash ^= i + 1
i = vhash ^ k_bits_to_embed
if not i:
break
i -= 1
coeff[code_word[i]] += 1 if coeff[
code_word[i]] < 0 else -1
_changed += 1
if not coeff[code_word[i]]:
_thrown += 1
code_word[i:i + 1] = []
code_word.extend(filtered_index.offer(1))
else:
break
except FilteredCollection.ListNotEnough:
pass
if _examined > 0:
logger.info('%d coefficients examined' % _examined)
if _changed > 0:
logger.info(
'%d coefficients changed (efficiency: %d.%d bits per change'
% (_changed, _embedded / _changed,
_embedded * 10 / _changed % 10))
logger.info('%d coefficients thrown (zeroed)' % _thrown)
logger.info('%d bits (%d bytes) embedded' %
(_embedded, _embedded / 8))
#导出嵌入后的系数coeff
if self.hasais:
filename2 = 'embeded_ais.json'
else:
filename2 = 'embeded.json'
with open(filename2, 'w') as f_embeded:
json.dump(coeff, f_embeded)
logger.info('starting hufman encoding')
shuffled_index = 0
for r in range(min_block_height):
for c in range(min_block_width):
for comp in range(self.jpeg_obj.comp_num):
for i in range(self.jpeg_obj.vsamp_factor[comp]):
for j in range(self.jpeg_obj.hsamp_factor[comp]):
dct_array3 = coeff[shuffled_index:shuffled_index +
64]
self.huf.huffman_block_encoder(
self.out, dct_array3, last_dc_value[comp],
self.jpeg_obj.dctable_number[comp],
self.jpeg_obj.actable_number[comp])
last_dc_value[comp] = dct_array3[0]
shuffled_index += 64
self.huf.flush_buffer(self.out)
logger.info('hufman encode end')
class HuffmanDecode(object):
APP = [
0xe0, 0xe1, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea, 0xeb, 0xec,
0xed, 0xee, 0xef
]
DRI, DNL, EOI = 0xdd, 0xdc, 0xd9
deZZ = [[0, 0], [0, 1], [1, 0], [2, 0], [1, 1], [0, 2], [0, 3], [1, 2],
[2, 1], [3, 0], [4, 0], [3, 1], [2, 2], [1, 3], [0, 4], [0, 5],
[1, 4], [2, 3], [3, 2], [4, 1], [5, 0], [6, 0], [5, 1], [4, 2],
[3, 3], [2, 4], [1, 5], [0, 6], [0, 7], [1, 6], [2, 5], [3, 4],
[4, 3], [5, 2], [6, 1], [7, 0], [7, 1], [6, 2], [5, 3], [4, 4],
[3, 5], [2, 6], [1, 7], [2, 7], [3, 6], [4, 5], [5, 4], [6, 3],
[7, 2], [7, 3], [6, 4], [5, 5], [4, 6], [3, 7], [4, 7], [5, 6],
[6, 5], [7, 4], [7, 5], [6, 6], [5, 7], [6, 7], [7, 6], [7, 7]]
de_zig_zag = [
0, 1, 5, 6, 14, 15, 27, 28, 2, 4, 7, 13, 16, 26, 29, 42, 3, 8, 12, 17,
25, 30, 41, 43, 9, 11, 18, 24, 31, 40, 44, 53, 10, 19, 23, 32, 39, 45,
52, 54, 20, 22, 33, 38, 46, 51, 55, 60, 21, 34, 37, 47, 50, 56, 59, 61,
35, 36, 48, 49, 57, 58, 62, 63
]
def __init__(self, data):
self.huffval = create_array([], 4)
self.valptr = create_array([], 4)
self.mincode = create_array([], 4)
self.maxcode = create_array([], 4)
self.zz = create_array(0, 64)
self.qnt = create_array(0, 4, 64)
self.data = EmbedData(data)
self.size = len(self.data)
self.ri = 0
while True:
if self.get_byte() == 255:
b = self.get_byte()
if b == 192:
self.sof0()
elif b == 196:
self.dht()
elif b == 219:
self.dqt()
elif b == 217 or b == 218:
break
elif b in self.APP:
self.skip_variable()
elif b == self.DRI:
self.dri()
def available(self):
return self.data.available()
def get_double_four_bits(self):
b = self.get_byte()
return b >> 4, b & 0x0f
def get_byte(self):
return self.data.read()
def get_int(self):
return (self.get_byte() << 8) ^ self.get_byte()
def get_next_bit(self):
if not self.CNT:
self.CNT = 8
self.B = self.get_byte()
if self.B == 255:
self.get_byte()
BIT = self.B & 0x80
BIT >>= 7
self.CNT -= 1
self.B <<= 1
return BIT
def get_block_count(self):
square = lambda x: x * x
if self.nf == 1:
return square((self.x + 7) / 8)
elif self.nf == 3:
return 6 * square((self.x + 15) / 16)
else:
logger.error('nf is not 1 neither 3')
def _internal_decode(self):
i, cd = 1, self.get_next_bit()
while cd > self.maxcode[self.hftbl][i]:
cd = (cd << 1) + self.get_next_bit()
i += 1
j = self.valptr[self.hftbl][i]
j += cd - self.mincode[self.hftbl][i]
return self.huffval[self.hftbl][j]
def receive(self, sss):
v, i = 0, 0
while i != sss:
i += 1
v = (v << 1) + self.get_next_bit()
return v
def extend(self, v, t):
if t == 0:
return v
vt = 0x01 << t - 1
if v < vt:
vt = (-1 << t) + 1
v += vt
return v
def decode_ac_coefficients(self):
k = 1
self.zz = [0] * 64
while True:
rs = self._internal_decode()
ssss = rs % 16
r = rs >> 4
if ssss == 0:
if r == 15:
k += 16
else:
return
else:
k += r
self.zz[k] = self.extend(self.receive(ssss), ssss)
if k == 63:
return
else:
k += 1
def decode(self):
pred = create_array(0, self.nf)
self.CNT = 0
self.ls = self.get_int()
self.ns = self.get_byte()
cs = create_array(0, self.ns)
td = create_array(0, self.ns)
ta = create_array(0, self.ns)
for lp in range(self.ns):
cs[lp] = self.get_byte()
td[lp], ta[lp] = self.get_double_four_bits()
self.ss = self.get_byte()
self.se = self.get_byte()
self.ah, self.al = self.get_double_four_bits()
buff = create_array(0, 2 * 8 * 8 * self.get_block_count())
pos, mcu_count = 0, 0
while True:
for n_comp in range(0, self.nf):
for cnt in range(self.h[n_comp] * self.v[n_comp]):
self.hftbl = td[n_comp] * 2
tmp = self._internal_decode()
self.diff = self.receive(tmp)
self.zz[0] = pred[0] + self.extend(self.diff, tmp)
pred[n_comp] = self.zz[0]
self.hftbl = ta[n_comp] * 2 + 1
self.decode_ac_coefficients()
for lp in range(64):
buff[pos] = self.zz[lp]
pos += 1
mcu_count += 1
if mcu_count == self.ri:
mcu_count = 0
self.CNT = 0
pred[n_comp] = create_array(0, self.nf)
self.get_byte()
tmp_b = self.get_byte()
if tmp_b == EOI:
break
if self.available() <= 2:
if self.available() == 2:
self.get_byte()
if self.get_byte() != self.EOI:
logger.error('file does not end with EOI')
else:
if self.available() == 1:
logger.error('last byte: %X' % self.get_byte())
logger.error('file does not end with EOI')
break
return buff[:pos]
def sof0(self):
self.lf = self.get_int()
self.p = self.get_byte()
self.y = self.get_int()
self.x = self.get_int()
self.nf = self.get_byte()
self.c = create_array(0, self.nf)
self.h = create_array(0, self.nf)
self.v = create_array(0, self.nf)
self.t = create_array(0, self.nf)
for lp in range(self.nf):
self.c[lp] = self.get_byte()
self.h[lp], self.v[lp] = self.get_double_four_bits()
self.t[lp] = self.get_byte()
def dht(self):
self.lh = self.get_int()
def _fill_value(index):
ht = HuffTable(self.data, self.lh)
self.lh -= ht.get_len()
self.huffval[index] = ht.get_huffval()
self.valptr[index] = ht.get_valptr()
self.maxcode[index] = ht.get_maxcode()
self.mincode[index] = ht.get_mincode()
while self.lh > 0:
self.tc, self.th = self.get_double_four_bits()
if self.th == 0:
if self.tc == 0:
_fill_value(0)
else:
_fill_value(1)
else:
if self.tc == 0:
_fill_value(2)
else:
_fill_value(3)
def dqt(self):
self.lq = self.get_int()
self.pq, self.tq = self.get_double_four_bits()
if self.tq in range(4):
for lp in range(64):
self.qnt[self.tq][lp] = self.get_byte()
def dri(self):
self.get_int()
self.ri = self.get_int()
def skip_variable(self):
for i in range(self.get_int() - 2):
self.get_byte()
class JpegEncoder(object):
def __init__(self, image, quality, out, comment):
self.quality = quality
self.jpeg_obj = JpegInfo(image, comment)
self.image_width, self.image_height = image.size
self.out = out
self.dct = DCT(self.quality)
self.huf = Huffman(*image.size)
def compress(self, embedded_data=None, password='******'):
self.embedded_data = EmbedData(embedded_data) if embedded_data else None
self.password = password
self.write_headers()
self.write_compressed_data()
self.write_eoi()
self.out.flush()
def get_quality(self):
return self.quality
def set_quality(self, quality):
self.quality = quality
self.dct = DCT(quality)
def write_array(self, data):
length = ((data[2] & 0xff) << 8) + (data[3] & 0xff) + 2
self.out.write(bytearray(data[:length]))
def write_marker(self, data):
self.out.write(bytearray(data[:2]))
def write_eoi(self):
EOI = [0xff, 0xD9]
self.write_marker(EOI)
def write_headers(self):
SOI = [0xff, 0xD8]
self.write_marker(SOI)
JFIF = [0xff, 0xe0, 0x00, 0x10, 0x4a, 0x46,
0x49, 0x46, 0x00, 0x01, 0x01, 0x01,
0x00, 0x60, 0x00, 0x60, 0x00, 0x00]
self.write_array(JFIF)
comment = self.jpeg_obj.get_comment()
if comment:
length = len(comment) + 2
COM = [0xff, 0xfe, length >> 8 & 0xff, length & 0xff]
COM.extend(comment)
self.write_array(COM)
DQT = [0xff, 0xdb, 0x00, 0x84]
for k in range(2):
DQT.append(k)
DQT.extend([self.dct.quantum[k][JPEG_NATURAL_ORDER[i]] for i in range(64)])
self.write_array(DQT)
SOF = [0xff, 0xc0, 0x00, 0x11,
self.jpeg_obj.precision,
self.jpeg_obj.image_height >> 8 & 0xff,
self.jpeg_obj.image_height & 0xff,
self.jpeg_obj.image_width >> 8 & 0xff,
self.jpeg_obj.image_width & 0xff,
self.jpeg_obj.comp_num]
for i in range(self.jpeg_obj.comp_num):
SOF.append(self.jpeg_obj.com_id[i])
SOF.append(eight_byte(self.jpeg_obj.hsamp_factor[i], self.jpeg_obj.vsamp_factor[i]))
SOF.append(self.jpeg_obj.qtable_number[i])
self.write_array(SOF)
DHT = [0xff, 0xc4, 0, 0]
for i in range(4):
DHT.extend(self.huf.BITS[i])
DHT.extend(self.huf.VAL[i])
DHT[2] = len(DHT) - 2 >> 8 & 0xff
DHT[3] = len(DHT) - 2 & 0xff
self.write_array(DHT)
SOS = [0] * 14
SOS = [0xff, 0xda, 0x00, 0x0c, self.jpeg_obj.comp_num]
for i in range(self.jpeg_obj.comp_num):
SOS.append(self.jpeg_obj.com_id[i])
SOS.append(eight_byte(self.jpeg_obj.dctable_number[i], self.jpeg_obj.actable_number[i]))
SOS.append(self.jpeg_obj.ss)
SOS.append(self.jpeg_obj.se)
SOS.append(eight_byte(self.jpeg_obj.ah, self.jpeg_obj.al))
self.write_array(SOS)
def _get_coeff(self):
dct_array1 = create_array(0.0, 8, 8)
dct_array2 = create_array(0.0, 8, 8)
dct_array3 = create_array(0, 64)
coeff = []
for r in range(min(self.jpeg_obj.block_height)):
for c in range(min(self.jpeg_obj.block_width)):
xpos = c * 8
ypos = r * 8
for comp in range(self.jpeg_obj.comp_num):
indata = self.jpeg_obj.components[comp]
maxa = self.image_height / 2 * self.jpeg_obj.vsamp_factor[comp] - 1
maxb = self.image_width / 2 * self.jpeg_obj.hsamp_factor[comp] - 1
for i in range(self.jpeg_obj.vsamp_factor[comp]):
for j in range(self.jpeg_obj.hsamp_factor[comp]):
ia = ypos * self.jpeg_obj.vsamp_factor[comp] + i * 8
ib = xpos * self.jpeg_obj.hsamp_factor[comp] + j * 8
for a in range(8):
for b in range(8):
dct_array1[a][b] = indata[min(ia+a, maxa)][min(ib+b, maxb)]
dct_array2 = self.dct.forward_dct(dct_array1)
dct_array3 = self.dct.quantize_block(dct_array2,
self.jpeg_obj.qtable_number[comp])
coeff.extend(dct_array3[:64])
return coeff
def write_compressed_data(self):
tmp = 0
last_dc_value = create_array(0, self.jpeg_obj.comp_num)
zero_array = create_array(0, 64)
width, height = 0, 0
min_block_width = min(self.jpeg_obj.block_width)
min_block_height = min(self.jpeg_obj.block_height)
logger.info('DCT/quantisation starts')
logger.info('%d x %d' % (self.image_width, self.image_height))
coeff = self._get_coeff()
coeff_count = len(coeff)
logger.info('got %d DCT AC/DC coefficients' % coeff_count)
_changed, _embedded, _examined, _expected, _one, _large, _thrown, _zero = 0, 0, 0, 0, 0, 0, 0, 0
shuffled_index = 0
for i, cc in enumerate(coeff):
if i % 64 == 0:
continue
if cc == 1 or cc == -1:
_one += 1
elif cc == 0:
_zero += 1
_large = coeff_count - _zero - _one - coeff_count / 64
_expected = _large + int(0.49 * _one)
logger.info('one=%d' % _one)
logger.info('large=%d' % _large)
logger.info('expected capacity: %d bits' % _expected)
logger.info('expected capacity with')
for i in range(1, 8):
n = (1 << i) - 1
changed = _large - _large % (n + 1)
changed = (changed + _one + _one / 2 - _one / (n + 1)) / (n + 1)
usable = (_expected * i / n - _expected * i / n % n) / 8
if usable == 0:
break
logger.info('%s code: %d bytes (efficiency: %d.%d bits per change)' % ('default' if i == 1 else '(1, %d, %d)' % (n, i), usable, usable * 8 / changed, usable * 80 / changed % 10))
if self.embedded_data is not None:
logger.info('permutation starts')
random = F5Random(self.password)
permutation = Permutation(coeff_count, random)
next_bit_to_embed = 0
byte_to_embed = len(self.embedded_data)
available_bits_to_embed = 0
logger.info('Embedding of %d bits (%d+4 bytes)' % (byte_to_embed * 8 + 32, byte_to_embed))
if byte_to_embed > 0x007fffff:
byte_to_embed = 0x007ffff
for i in range(1, 8):
self.n = (1 << i) - 1
usable = (_expected * i / self.n - _expected * i / self.n % self.n) / 8
if usable < byte_to_embed + 4:
break
k = i - 1
self.n = (1 << k) - 1
if self.n == 0:
logger.info('using default code, file will not fit')
self.n = 1
elif self.n == 1:
logger.info('using default code')
else:
logger.info('using (1, %d, %d) code' % (self.n, k))
byte_to_embed |= k << 24
byte_to_embed ^= random.get_next_byte()
byte_to_embed ^= random.get_next_byte() << 8
byte_to_embed ^= random.get_next_byte() << 16
byte_to_embed ^= random.get_next_byte() << 24
next_bit_to_embed = byte_to_embed & 1
byte_to_embed >>= 1
available_bits_to_embed = 31
_embedded += 1
for i, shuffled_index in enumerate(permutation.shuffled):
if shuffled_index % 64 == 0 or coeff[shuffled_index] == 0:
continue
cc = coeff[shuffled_index]
_examined += 1
if cc > 0 and (cc & 1) != next_bit_to_embed:
coeff[shuffled_index] -= 1
_changed +=1
elif cc < 0 and (cc & 1) == next_bit_to_embed:
coeff[shuffled_index] += 1
_changed += 1
if coeff[shuffled_index] != 0:
if available_bits_to_embed == 0:
if self.n > 1 or not self.embedded_data.available():
break
byte_to_embed = self.embedded_data.read()
byte_to_embed ^= random.get_next_byte()
available_bits_to_embed = 8
next_bit_to_embed = byte_to_embed & 1
byte_to_embed >>= 1
available_bits_to_embed -= 1
_embedded += 1
else:
_thrown += 1
if self.n > 1:
try:
is_last_byte = False
filtered_index = FilteredCollection(permutation.shuffled[i+1:], lambda index: index % 64 and coeff[index])
while not is_last_byte:
k_bits_to_embed = 0
for i in range(k):
if available_bits_to_embed == 0:
if not self.embedded_data.available():
is_last_byte = True
break
byte_to_embed = self.embedded_data.read()
byte_to_embed ^= random.get_next_byte()
available_bits_to_embed = 8
next_bit_to_embed = byte_to_embed & 1
byte_to_embed >>= 1
available_bits_to_embed -= 1
k_bits_to_embed |= next_bit_to_embed << i
_embedded += 1
code_word = filtered_index.offer(self.n)
while True:
vhash = 0
for i, index in enumerate(code_word):
if coeff[index] > 0:
extracted_bit = coeff[index] & 1
else:
extracted_bit = 1 - (coeff[index] & 1)
if extracted_bit == 1:
vhash ^= i + 1
i = vhash ^ k_bits_to_embed
if not i:
break
i -= 1
coeff[code_word[i]] += 1 if coeff[code_word[i]] < 0 else -1
_changed += 1
if not coeff[code_word[i]]:
_thrown += 1
code_word[i:i+1] = []
code_word.extend(filtered_index.offer(1))
else:
break
except FilteredCollection.ListNotEnough:
pass
if _examined > 0:
logger.info('%d coefficients examined' % _examined)
if _changed > 0:
logger.info('%d coefficients changed (efficiency: %d.%d bits per change' % (_changed, _embedded / _changed, _embedded * 10 / _changed % 10))
logger.info('%d coefficients thrown (zeroed)' % _thrown)
logger.info('%d bits (%d bytes) embedded' % (_embedded, _embedded / 8))
logger.info('starting hufman encoding')
shuffled_index = 0
for r in range(min_block_height):
for c in range(min_block_width):
for comp in range(self.jpeg_obj.comp_num):
for i in range(self.jpeg_obj.vsamp_factor[comp]):
for j in range(self.jpeg_obj.hsamp_factor[comp]):
dct_array3 = coeff[shuffled_index:shuffled_index+64]
self.huf.huffman_block_encoder(self.out, dct_array3, last_dc_value[comp],
self.jpeg_obj.dctable_number[comp], self.jpeg_obj.actable_number[comp])
last_dc_value[comp] = dct_array3[0]
shuffled_index += 64
self.huf.flush_buffer(self.out)
class HuffmanDecode(object):
APP = [0xE0, 0xE1, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA, 0xEB, 0xEC, 0xED, 0xEE, 0xEF]
DRI, DNL, EOI = 0xDD, 0xDC, 0xD9
deZZ = [
[0, 0],
[0, 1],
[1, 0],
[2, 0],
[1, 1],
[0, 2],
[0, 3],
[1, 2],
[2, 1],
[3, 0],
[4, 0],
[3, 1],
[2, 2],
[1, 3],
[0, 4],
[0, 5],
[1, 4],
[2, 3],
[3, 2],
[4, 1],
[5, 0],
[6, 0],
[5, 1],
[4, 2],
[3, 3],
[2, 4],
[1, 5],
[0, 6],
[0, 7],
[1, 6],
[2, 5],
[3, 4],
[4, 3],
[5, 2],
[6, 1],
[7, 0],
[7, 1],
[6, 2],
[5, 3],
[4, 4],
[3, 5],
[2, 6],
[1, 7],
[2, 7],
[3, 6],
[4, 5],
[5, 4],
[6, 3],
[7, 2],
[7, 3],
[6, 4],
[5, 5],
[4, 6],
[3, 7],
[4, 7],
[5, 6],
[6, 5],
[7, 4],
[7, 5],
[6, 6],
[5, 7],
[6, 7],
[7, 6],
[7, 7],
]
de_zig_zag = [
0,
1,
5,
6,
14,
15,
27,
28,
2,
4,
7,
13,
16,
26,
29,
42,
3,
8,
12,
17,
25,
30,
41,
43,
9,
11,
18,
24,
31,
40,
44,
53,
10,
19,
23,
32,
39,
45,
52,
54,
20,
22,
33,
38,
46,
51,
55,
60,
21,
34,
37,
47,
50,
56,
59,
61,
35,
36,
48,
49,
57,
58,
62,
63,
]
def __init__(self, data):
self.huffval = create_array([], 4)
self.valptr = create_array([], 4)
self.mincode = create_array([], 4)
self.maxcode = create_array([], 4)
self.zz = create_array(0, 64)
self.qnt = create_array(0, 4, 64)
self.data = EmbedData(data)
self.size = len(self.data)
self.ri = 0
while True:
if self.get_byte() == 255:
b = self.get_byte()
if b == 192:
self.sof0()
elif b == 196:
self.dht()
elif b == 219:
self.dqt()
elif b == 217 or b == 218:
break
elif b in self.APP:
self.skip_variable()
elif b == self.DRI:
self.dri()
def available(self):
return self.data.available()
def get_double_four_bits(self):
b = self.get_byte()
return b >> 4, b & 0x0F
def get_byte(self):
return self.data.read()
def get_int(self):
return (self.get_byte() << 8) ^ self.get_byte()
def get_next_bit(self):
if not self.CNT:
self.CNT = 8
self.B = self.get_byte()
if self.B == 255:
self.get_byte()
BIT = self.B & 0x80
BIT >>= 7
self.CNT -= 1
self.B <<= 1
return BIT
def get_block_count(self):
square = lambda x: x * x
if self.nf == 1:
return square((self.x + 7) / 8)
elif self.nf == 3:
return 6 * square((self.x + 15) / 16)
else:
logger.error("nf is not 1 neither 3")
def _internal_decode(self):
i, cd = 1, self.get_next_bit()
while cd > self.maxcode[self.hftbl][i]:
cd = (cd << 1) + self.get_next_bit()
i += 1
j = self.valptr[self.hftbl][i]
j += cd - self.mincode[self.hftbl][i]
return self.huffval[self.hftbl][j]
def receive(self, sss):
v, i = 0, 0
while i != sss:
i += 1
v = (v << 1) + self.get_next_bit()
return v
def extend(self, v, t):
if t == 0:
return v
vt = 0x01 << t - 1
if v < vt:
vt = (-1 << t) + 1
v += vt
return v
def decode_ac_coefficients(self):
k = 1
self.zz = [0] * 64
while True:
rs = self._internal_decode()
ssss = rs % 16
r = rs >> 4
if ssss == 0:
if r == 15:
k += 16
else:
return
else:
k += r
self.zz[k] = self.extend(self.receive(ssss), ssss)
if k == 63:
return
else:
k += 1
def decode(self):
pred = create_array(0, self.nf)
self.CNT = 0
self.ls = self.get_int()
self.ns = self.get_byte()
cs = create_array(0, self.ns)
td = create_array(0, self.ns)
ta = create_array(0, self.ns)
for lp in range(self.ns):
cs[lp] = self.get_byte()
td[lp], ta[lp] = self.get_double_four_bits()
self.ss = self.get_byte()
self.se = self.get_byte()
self.ah, self.al = self.get_double_four_bits()
buff = create_array(0, 2 * 8 * 8 * self.get_block_count())
pos, mcu_count = 0, 0
while True:
for n_comp in range(0, self.nf):
for cnt in range(self.h[n_comp] * self.v[n_comp]):
self.hftbl = td[n_comp] * 2
tmp = self._internal_decode()
self.diff = self.receive(tmp)
self.zz[0] = pred[0] + self.extend(self.diff, tmp)
pred[n_comp] = self.zz[0]
self.hftbl = ta[n_comp] * 2 + 1
self.decode_ac_coefficients()
for lp in range(64):
buff[pos] = self.zz[lp]
pos += 1
mcu_count += 1
if mcu_count == self.ri:
mcu_count = 0
self.CNT = 0
pred[n_comp] = create_array(0, self.nf)
self.get_byte()
tmp_b = self.get_byte()
if tmp_b == EOI:
break
if self.available() <= 2:
if self.available() == 2:
self.get_byte()
if self.get_byte() != self.EOI:
logger.error("file does not end with EOI")
else:
if self.available() == 1:
logger.error("last byte: %X" % self.get_byte())
logger.error("file does not end with EOI")
break
return buff[:pos]
def sof0(self):
self.lf = self.get_int()
self.p = self.get_byte()
self.y = self.get_int()
self.x = self.get_int()
self.nf = self.get_byte()
self.c = create_array(0, self.nf)
self.h = create_array(0, self.nf)
self.v = create_array(0, self.nf)
self.t = create_array(0, self.nf)
for lp in range(self.nf):
self.c[lp] = self.get_byte()
self.h[lp], self.v[lp] = self.get_double_four_bits()
self.t[lp] = self.get_byte()
def dht(self):
self.lh = self.get_int()
def _fill_value(index):
ht = HuffTable(self.data, self.lh)
self.lh -= ht.get_len()
self.huffval[index] = ht.get_huffval()
self.valptr[index] = ht.get_valptr()
self.maxcode[index] = ht.get_maxcode()
self.mincode[index] = ht.get_mincode()
while self.lh > 0:
self.tc, self.th = self.get_double_four_bits()
if self.th == 0:
if self.tc == 0:
_fill_value(0)
else:
_fill_value(1)
else:
if self.tc == 0:
_fill_value(2)
else:
_fill_value(3)
def dqt(self):
self.lq = self.get_int()
self.pq, self.tq = self.get_double_four_bits()
if self.tq in range(4):
for lp in range(64):
self.qnt[self.tq][lp] = self.get_byte()
def dri(self):
self.get_int()
self.ri = self.get_int()
def skip_variable(self):
for i in range(self.get_int() - 2):
self.get_byte()