def _create_new_byte_of_data(current_byte, list_of_pairs, i):
bin_repr_current_byte = Stuff.get_bin_str_from_bytearray(current_byte)
# current_pairs = Stuff.split_in_two_bits(bin_repr_current_byte)
current_pairs = list(bin_repr_current_byte)
current_pairs[-1] = list_of_pairs[i]
new_byte = Stuff.get_int_from_bin(''.join(current_pairs))
return new_byte
def get_hidden_information(self):
offset = bytes_per_sample = self.bits_per_sample // 8
index = self.index_of_start_of_data + bytes_per_sample
bytes_to_describe_length = 32
index, length_description = self._read_the_flag(
bytes_to_describe_length, index, offset)
length = Stuff.get_int_from_bin(length_description)
length_of_new_bytearray = length // 8
bytes_to_describe_hash = 8
index, length_of_hash_description = self._read_the_flag(
bytes_to_describe_hash, index, offset)
length_of_hash = Stuff.get_int_from_bin(length_of_hash_description)
index, rec_hash = self._read_the_hash(length_of_hash, index, offset)
content_of_recieved = bytearray(length_of_new_bytearray)
index += self._read_the_content(content_of_recieved, length, index,
offset)
actual_hash = Stuff.get_hash(content_of_recieved)
self._compare_the_checksum(actual_hash, rec_hash)
self.create_files(content_of_recieved)
def _read_the_hash(self, length_of_hash, index, offset):
hash_str = ''
for i in range(length_of_hash): # считываем хеш
current_byte = self.main_file[index: index + 1]
bin_repr_current_byte = Stuff.get_bin_str_from_bytearray(current_byte)
# current_pairs = Stuff.split_in_two_bits(bin_repr_current_byte) это если кодировать по два бита
current_pairs = list(bin_repr_current_byte)
hash_str += current_pairs[-1]
index += offset
rec_hash = Stuff.get_int_from_bin(hash_str)
return index, rec_hash
def _read_the_hash(self, length_of_hash, index, offset):
hash_str = ''
for i in range(length_of_hash):
current_byte = self.main_file[index:index + 1]
bin_repr_current_byte = \
Stuff.get_bin_str_from_bytearray(current_byte)
current_pairs = list(bin_repr_current_byte)
hash_str += current_pairs[-1]
index += offset
rec_hash = Stuff.get_int_from_bin(hash_str)
return index, rec_hash
def review_the_same_bytes(self, count_of_same, prev_byte):
if count_of_same != 0:
while count_of_same > 127:
self.result_data.append(255)
self.result_data.append(prev_byte)
count_of_same -= 127
new_byte = '1' + bin(count_of_same)[2:].zfill(7)
self.result_data.append(Stuff.get_int_from_bin(new_byte))
self.result_data.append(prev_byte)
count_of_same = 0
return count_of_same
def review_diff_bytes(self, diff_bytes: deque):
if len(diff_bytes) != 0:
while len(diff_bytes) > 127:
self.result_data.append(127)
for i in range(127):
self.result_data.append(diff_bytes.popleft())
new_byte = Stuff.get_bin_from_int(len(diff_bytes))
self.result_data.append(Stuff.get_int_from_bin(new_byte))
for i in range(len(diff_bytes)):
self.result_data.append(diff_bytes.popleft())
return diff_bytes
def get_hidden_information(self):
offset = bytes_per_sample = self.bits_per_sample // 8
index = self.index_of_start_of_data + bytes_per_sample # индекс первого байта
bytes_to_describe_length = 32
index, length_description = self._read_the_flag(
bytes_to_describe_length,
index,
offset
)
length = Stuff.get_int_from_bin(length_description)
length_of_new_bytearray = length // 8
bytes_to_describe_length_of_name = 16
index, length_of_name_description = self._read_the_flag(
bytes_to_describe_length_of_name,
index,
offset
)
length_of_name = Stuff.get_int_from_bin(length_of_name_description)
length_of_name_array = length_of_name // 8
bytes_to_describe_hash = 8
index, length_of_hash_description = self._read_the_flag(
bytes_to_describe_hash,
index,
offset
)
length_of_hash = Stuff.get_int_from_bin(length_of_hash_description) # длина хеша
index, rec_hash = self._read_the_hash(length_of_hash, index, offset)
name_bytearray = bytearray(length_of_name_array)
index = self._read_the_content(name_bytearray, length_of_name, index, offset)
name_of_recieved = name_bytearray.decode()
content_of_recieved = bytearray(length_of_new_bytearray)
self._read_the_content(content_of_recieved, length, index, offset)
actual_hash = Stuff.get_hash(content_of_recieved)
self._compare_the_checksum(actual_hash, rec_hash)
with open('(recieved) ' + name_of_recieved, 'wb') as file:
file.write(content_of_recieved)
def _read_the_content(self, buffer, length, index, offset):
string_repr = ''
buffer_index = 0
for i in range(length):
current_byte = self.main_file[index: index + 1]
bin_repr_current_byte = Stuff.get_bin_str_from_bytearray(current_byte)
# current_pairs = Stuff.split_in_two_bits(bin_repr_current_byte)
current_pairs = list(bin_repr_current_byte)
string_repr += current_pairs[-1]
if len(string_repr) == 8:
buffer[buffer_index] = Stuff.get_int_from_bin(string_repr)
string_repr = ''
buffer_index += 1
index += offset
return index
def test_get_int_from_bin(self):
bin_string = '00001010'
result = LSBStuff.get_int_from_bin(bin_string)
self.assertEqual(result, 10)
def _create_new_byte_of_flag(current_byte, description, i):
bin_repr_current_byte = Stuff.get_bin_str_from_bytearray(current_byte)
list_of_current_chars = list(bin_repr_current_byte)
list_of_current_chars[-1] = description[i]
new_byte = Stuff.get_int_from_bin(''.join(list_of_current_chars))
return new_byte