在Python中保留结构填充的填充字节

结构填充意味着将数据对齐到固定大小的块中，以便相应地简化特定计算机体系结构和密码算法的操作。我们填充（添加足够的字节）操作数据（不一定是结构化的）以便为机器服务。填充字节可能会中断原始数据，要确定填充字节的数量，以下方法会有所帮助。

这是以“空白”作为填充实体的传统结构填充，它不会帮助我们提取原始数据的精确字节

示例 1：

# padding with 'white spaces' 
def pad(text, block_size):
      
    # Calculate the missing number of bytes
    pad_size = block_size - len(text)% block_size
      
    # Add missing bytes with 'white spaces'
    fit_text = text + (" "*pad_size)
    return (fit_text)
def main():
      
    # text already contains 'white spaces' to 
    # the Right, assumptions go wrong here 
    block_size = 20
    text = "HALL OF BYTES   "  
    print(pad(text, block_size))
  
main()

输出 ：

'HALL OF BYTES       '

示例 2：

以下是如何保留填充的字节数

# Python Program to retain padded bytes
def pad(text, block_size):
      
    # Calculate the missing number of 
    # bytes, say N
    pad_size = block_size - len(text)% block_size
      
    # Pad with character of N
    fit_text = text + chr(pad_size)*pad_size
      
    return (fit_text, )
  
def main():
    text = "HALL OF BYTES"
      
    # structural unit of size 20
    block_size = 20
    print(pad(text, block_size))
  
# Driver Code
main()

输出 ：

'HALL OF BYTES\x07\x07\x07\x07\x07\x07\x07' 
# thus 7 bytes were padded. 

# appropriate method to retain padded bytes
def pad(text, block_size):
      
    # Calculate the missing number of 
    # bytes, say N
    pad_size = block_size - len(text)% block_size
      
    # Pad with character of N
    fit_text = text + chr(pad_size)*pad_size
      
    return (fit_text, )
  
def main():
    text = "PRECISELY RETAINED"
      
    # structural unit of size 20
    block_size = 20
    print(pad(text, block_size))
      
# Driver Code
main()

输出 ：

'PRECISELY RETAINED\x02\x02' 
# Thus two bytes were padded.