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 __init__(self, quality):
self.N = 8
self.QUALITY = 80
self.quantum = create_array(0, 2, self.N * self.N)
self.divisors = create_array(0, 2, self.N * self.N)
self.init_matrix(quality)
def get_ycc_array(self):
max_hsamp_factor = max(self.hsamp_factor)
max_vsamp_factor = max(self.vsamp_factor)
for i in range(self.comp_num):
self.comp_width[i] = int(math.ceil(self.image_width / 8.0) * 8)
self.comp_width[i] = self.comp_width[i] / max_hsamp_factor * self.hsamp_factor[i]
self.block_width[i] = int(math.ceil(self.comp_width[i] / 8.0))
self.comp_height[i] = int(math.ceil(self.image_height / 8.0) * 8)
self.comp_height[i] = self.comp_height[i] / max_vsamp_factor * self.vsamp_factor[i]
self.block_height[i] = int(math.ceil(self.comp_height[i] / 8.0))
values = self.pixels
Y = create_array(0, self.comp_height[0], self.comp_width[0])
Cb = create_array(0, self.comp_height[0], self.comp_width[0])
Cr = create_array(0, self.comp_height[0], self.comp_width[0])
for y in range(self.image_height):
for x in range(self.image_width):
r, g, b = values[x, y]
Y[y][x] = 0.299 * r + 0.587 * g + 0.114 * b
Cb[y][x] = -0.16874 * r - 0.33126 * g + 0.5 * b + 128
Cr[y][x] = 0.5 * r - 0.41869 * g - 0.08131 * b + 128
self.components = [Y, self.down_sample(Cb, 1), self.down_sample(Cr, 2)]
def __init__(self, quality):
self.N = 8
self.QUALITY = 80
self.quantum = create_array(0, 2, self.N * self.N)
self.divisors = create_array(0, 2, self.N * self.N)
self.init_matrix(quality)
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 get_ycc_array(self):
max_hsamp_factor = max(self.hsamp_factor)
max_vsamp_factor = max(self.vsamp_factor)
for i in range(self.comp_num):
self.comp_width[i] = int(math.ceil(self.image_width / 8.0) * 8)
self.comp_width[i] = self.comp_width[
i] / max_hsamp_factor * self.hsamp_factor[i]
self.block_width[i] = int(math.ceil(self.comp_width[i] / 8.0))
self.comp_height[i] = int(math.ceil(self.image_height / 8.0) * 8)
self.comp_height[i] = self.comp_height[
i] / max_vsamp_factor * self.vsamp_factor[i]
self.block_height[i] = int(math.ceil(self.comp_height[i] / 8.0))
values = self.pixels
Y = create_array(0, self.comp_height[0], self.comp_width[0])
Cb = create_array(0, self.comp_height[0], self.comp_width[0])
Cr = create_array(0, self.comp_height[0], self.comp_width[0])
for y in range(self.image_height):
for x in range(self.image_width):
r, g, b = values[x, y]
Y[y][x] = 0.299 * r + 0.587 * g + 0.114 * b
Cb[y][x] = -0.16874 * r - 0.33126 * g + 0.5 * b + 128
Cr[y][x] = 0.5 * r - 0.41869 * g - 0.08131 * b + 128
self.components = [Y, self.down_sample(Cb, 1), self.down_sample(Cr, 2)]
def __init__(self, image, comment):
self.components = create_array(None, self.comp_num)
self.comp_width = create_array(0, self.comp_num)
self.comp_height = create_array(0, self.comp_num)
self.block_width = create_array(0, self.comp_num)
self.block_height = create_array(0, self.comp_num)
self.comment = comment
self.image_width, self.image_height = image.size
self.pixels = image.load()
self.get_ycc_array()
def __init__(self, image, comment):
self.components = create_array(None, self.comp_num)
self.comp_width = create_array(0, self.comp_num)
self.comp_height = create_array(0, self.comp_num)
self.block_width = create_array(0, self.comp_num)
self.block_height = create_array(0, self.comp_num)
self.comment = comment
self.image_width, self.image_height = image.size
self.pixels = image.load()
self.get_ycc_array()
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 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 init_huf(self):
self.dc_matrix = create_array(0, 2, 12, 2)
self.ac_matrix = create_array(0, 2, 255, 2)
def cal(bits, val, matrix):
p = 0
code = 0
for l in range(1, len(bits)):
for i in range(bits[l]):
matrix[val[p]] = (code, l)
p += 1
code += 1
code <<= 1
cal(self.BITS_DC_LUMINANCE, self.VAL_DC_LUMINANCE, self.dc_matrix[0])
cal(self.BITS_AC_LUMINANCE, self.VAL_AC_LUMINANCE, self.ac_matrix[0])
cal(self.BITS_DC_CHROMINANCE, self.VAL_DC_CHROMINANCE, self.dc_matrix[1])
cal(self.BITS_AC_CHROMINANCE, self.VAL_AC_CHROMINANCE, self.ac_matrix[1])
def init_huf(self):
self.dc_matrix = create_array(0, 2, 12, 2)
self.ac_matrix = create_array(0, 2, 255, 2)
def cal(bits, val, matrix):
p = 0
code = 0
for l in range(1, len(bits)):
for i in range(bits[l]):
matrix[val[p]] = (code, l)
p += 1
code += 1
code <<= 1
cal(self.BITS_DC_LUMINANCE, self.VAL_DC_LUMINANCE, self.dc_matrix[0])
cal(self.BITS_AC_LUMINANCE, self.VAL_AC_LUMINANCE, self.ac_matrix[0])
cal(self.BITS_DC_CHROMINANCE, self.VAL_DC_CHROMINANCE,
self.dc_matrix[1])
cal(self.BITS_AC_CHROMINANCE, self.VAL_AC_CHROMINANCE,
self.ac_matrix[1])
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 __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 __init__(self, data, l):
self.bits = create_array(0, 17)
self.huffval = create_array(0, 256)
self.huffcode = create_array(0, 257)
self.huffsize = create_array(0, 257)
self.ehufco = create_array(0, 257)
self.ehufsi = create_array(0, 257)
self.mincode = create_array(0, 17)
self.maxcode = create_array(0, 18)
self.valptr = create_array(0, 17)
self.data = data
self.ln = 19 + self.get_table_data()
self.generate_size_table()
self.generate_code_table()
self.order_codes()
self.decode_tables()
def __init__(self, data, l):
self.bits = create_array(0, 17)
self.huffval = create_array(0, 256)
self.huffcode = create_array(0, 257)
self.huffsize = create_array(0, 257)
self.ehufco = create_array(0, 257)
self.ehufsi = create_array(0, 257)
self.mincode = create_array(0, 17)
self.maxcode = create_array(0, 18)
self.valptr = create_array(0, 17)
self.data = data
self.ln = 19 + self.get_table_data()
self.generate_size_table()
self.generate_code_table()
self.order_codes()
self.decode_tables()
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 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 forward_dct_extreme(self, indata):
output = create_array(0.0, self.N, self.N)
my_cos = lambda x: math.cos((2.0 * x + 1) * u * math.PI / 16)
special = lambda x: 1.0 / math.sqrt(2) if x == 0 else 1.0
range_8 = range(8)
for v in range_8:
for u in range_8:
for x in range_8:
for y in range_8:
output[v][u] += indata[x][y] * my_cos(x) * my_cos(y)
output[v][u] *= 0.25 * special(u) * special(v)
return output
def forward_dct_extreme(self, indata):
output = create_array(0.0, self.N, self.N)
my_cos = lambda x: math.cos((2.0 * x + 1) * u * math.PI / 16)
special = lambda x: 1.0 / math.sqrt(2) if x == 0 else 1.0
range_8 = range(8)
for v in range_8:
for u in range_8:
for x in range_8:
for y in range_8:
output[v][u] += indata[x][y] * my_cos(x) * my_cos(y)
output[v][u] *= 0.25 * special(u) * special(v)
return output
def create_array(self, ResourceAttr):
#A scenario attribute is a piece of data associated
#with a resource attribute.
#[[1, 2, 3], [4, 5, 6], [7, 8, 9]]
return util.create_array(self.client, ResourceAttr)
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)
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')
def forward_dct(self, indata):
output = [[indata[i][j] - 128.0 for j in range(0, 8)]
for i in range(0, 8)]
tmp = create_array(0, 14)
for i in range(8):
for j in range(4):
tmp[j] = output[i][j] + output[i][7 - j]
tmp[7 - j] = output[i][j] - output[i][7 - j]
output[i][0] = tmp[0] + tmp[3] + (tmp[1] + tmp[2])
output[i][4] = tmp[0] + tmp[3] - (tmp[1] + tmp[2])
tmp[12] = tmp[1] - tmp[2]
tmp[13] = tmp[0] - tmp[3]
z1 = (tmp[12] + tmp[13]) * 0.707106781
output[i][2] = tmp[13] + z1
output[i][6] = tmp[13] - z1
tmp[10] = tmp[4] + tmp[5]
tmp[11] = tmp[5] + tmp[6]
tmp[12] = tmp[6] + tmp[7]
z5 = (tmp[10] - tmp[12]) * 0.382683433
z2 = 0.541196100 * tmp[10] + z5
z4 = 1.306562965 * tmp[12] + z5
z3 = tmp[11] * 0.707106781
z11 = tmp[7] + z3
z13 = tmp[7] - z3
output[i][5] = z13 + z2
output[i][3] = z13 - z2
output[i][1] = z11 + z4
output[i][7] = z11 - z4
for i in range(8):
for j in range(4):
tmp[j] = output[j][i] + output[7 - j][i]
tmp[7 - j] = output[j][i] - output[7 - j][i]
output[0][i] = tmp[0] + tmp[3] + (tmp[1] + tmp[2])
output[4][i] = tmp[0] + tmp[3] - (tmp[1] + tmp[2])
tmp[12] = tmp[1] - tmp[2]
tmp[13] = tmp[0] - tmp[3]
z1 = (tmp[12] + tmp[13]) * 0.707106781
output[2][i] = tmp[13] + z1
output[6][i] = tmp[13] - z1
tmp[10] = tmp[4] + tmp[5]
tmp[11] = tmp[5] + tmp[6]
tmp[12] = tmp[6] + tmp[7]
z5 = (tmp[10] - tmp[12]) * 0.382683433
z2 = 0.541196100 * tmp[10] + z5
z4 = 1.306562965 * tmp[12] + z5
z3 = tmp[11] * 0.707106781
z11 = tmp[7] + z3
z13 = tmp[7] - z3
output[5][i] = z13 + z2
output[3][i] = z13 - z2
output[1][i] = z11 + z4
output[7][i] = z11 - z4
return output
def forward_dct(self, indata):
output = [[indata[i][j] - 128.0 for j in range(0, 8)] for i in range(0, 8)]
tmp = create_array(0, 14)
for i in range(8):
for j in range(4):
tmp[j] = output[i][j] + output[i][7-j]
tmp[7-j] = output[i][j] - output[i][7-j]
output[i][0] = tmp[0] + tmp[3] + (tmp[1] + tmp[2])
output[i][4] = tmp[0] + tmp[3] - (tmp[1] + tmp[2])
tmp[12] = tmp[1] - tmp[2]
tmp[13] = tmp[0] - tmp[3]
z1 = (tmp[12] + tmp[13]) * 0.707106781
output[i][2] = tmp[13] + z1
output[i][6] = tmp[13] - z1
tmp[10] = tmp[4] + tmp[5]
tmp[11] = tmp[5] + tmp[6]
tmp[12] = tmp[6] + tmp[7]
z5 = (tmp[10] - tmp[12]) * 0.382683433
z2 = 0.541196100 * tmp[10] + z5
z4 = 1.306562965 * tmp[12] + z5
z3 = tmp[11] * 0.707106781
z11 = tmp[7] + z3
z13 = tmp[7] - z3
output[i][5] = z13 + z2
output[i][3] = z13 - z2
output[i][1] = z11 + z4
output[i][7] = z11 - z4
for i in range(8):
for j in range(4):
tmp[j] = output[j][i] + output[7-j][i]
tmp[7-j] = output[j][i] - output[7-j][i]
output[0][i] = tmp[0] + tmp[3] + (tmp[1] + tmp[2])
output[4][i] = tmp[0] + tmp[3] - (tmp[1] + tmp[2])
tmp[12] = tmp[1] - tmp[2]
tmp[13] = tmp[0] - tmp[3]
z1 = (tmp[12] + tmp[13]) * 0.707106781
output[2][i] = tmp[13] + z1
output[6][i] = tmp[13] - z1
tmp[10] = tmp[4] + tmp[5]
tmp[11] = tmp[5] + tmp[6]
tmp[12] = tmp[6] + tmp[7]
z5 = (tmp[10] - tmp[12]) * 0.382683433
z2 = 0.541196100 * tmp[10] + z5
z4 = 1.306562965 * tmp[12] + z5
z3 = tmp[11] * 0.707106781
z11 = tmp[7] + z3
z13 = tmp[7] - z3
output[5][i] = z13 + z2
output[3][i] = z13 - z2
output[1][i] = z11 + z4
output[7][i] = z11 - z4
return output
def create_array(self, ResourceAttr):
#A scenario attribute is a piece of data associated
#with a resource attribute.
#[[1, 2, 3], [4, 5, 6], [7, 8, 9]]
return util.create_array(self.client, ResourceAttr)