67 lines
1.9 KiB
Python
67 lines
1.9 KiB
Python
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# -*- coding: utf-8 -*-
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"""
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Created on Tue Jun 11 16:10:51 2019
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@author: Administrator
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"""
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from Jsteg import Jsteg
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class F4(Jsteg):
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def __init__(self):
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Jsteg.__init__(self)
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def set_sequence_after_dct(self,sequence_after_dct):
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self.sequence_after_dct=sequence_after_dct
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sum_len=len(self.sequence_after_dct)
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zero_len=len([i for i in self.sequence_after_dct if i==0])
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one_len=len([i for i in self.sequence_after_dct if i in (-1,1)])
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self.available_info_len=sum_len-zero_len-one_len # 不是特别可靠
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print ("Load>> 大约可嵌入",sum_len-zero_len-int(one_len/2),'bits')
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print ("Load>> 最少可嵌入",self.available_info_len,'bits\n')
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def _write(self,index,data):
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origin=self.sequence_after_dct[index]
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if origin == 0:
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return False
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elif origin == 1 and data==0:
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self.sequence_after_dct[index]=0
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return False
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elif origin == -1 and data==1:
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self.sequence_after_dct[index]=0
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return False
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lower_bit=origin%2
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if origin >0:
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if lower_bit!=data:
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self.sequence_after_dct[index]=origin-1
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else:
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if lower_bit==data:
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self.sequence_after_dct[index]=origin+1
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return True
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def _read(self,index):
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if self.sequence_after_dct[index] >0:
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return self.sequence_after_dct[index]%2
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elif self.sequence_after_dct[index]<0:
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return (self.sequence_after_dct[index]+1)%2
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else:
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return None
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if __name__=="__main__":
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f4=F4()
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# 写
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sequence_after_dct=[-1,0,1]*100+[i for i in range(-7,500)]
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f4.set_sequence_after_dct(sequence_after_dct)
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info1=[0,1,0,1,1,0,1,0]
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f4.write(info1)
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# 读
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sequence_after_dct2=f4.get_sequence_after_dct()
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f4.set_sequence_after_dct(sequence_after_dct2)
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info2=f4.read()
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print (info2)
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