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Revision 4116

Added by Aaron Marcuse-Kubitza over 12 years ago

strings.py: concat(): Apply length limits by shrinking max_len by new raw_extra_len() of the strings. This also fixes a bug where multi-byte characters in str0 were not properly taken into account, leading to overly long strings. Added doc comment.

View differences:

lib/strings.py
23 23 
    return len(to_raw_str(str_))-len(str_)
24 24 

  		




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def concat(str0, str1, max_len):


  		




  26
  
  
    
    # Use to_unicode so that substring does not split Unicode characters


  		




  27
  
  
    
    str0, str1 = map(to_unicode, [str0, str1])


  		




  28
  
  
    
    # Use to_raw_str() because Unicode characters can be multi-byte, and length


  		




  29
  
  
    
    # limits often apply to the byte length, not the character length.


  		




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    return str0[:max_len-len(to_raw_str(str1))]+str1


  		




  
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    '''Concatenates two strings, ensuring that the combined byte length is no


  		




  
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    greater than the provided length limit.


  		




  
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    Note that if the combined length is longer than max_len, the truncated


  		




  
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    length may sometimes be shorter than max_len if there are multi-byte


  		




  
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    characters after str0's truncation point. Thus, you *cannot determine if the


  		




  
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    string was truncated* by checking if the new length equals max_len.


  		




  
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    '''


  		




  
  33
  
    
    # Use raw_extra_len() because Unicode characters can be multi-byte, and


  		




  
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    # length limits often apply to the byte length, not the character length.


  		




  
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    max_len -= raw_extra_len(str0)+raw_extra_len(str1)


  		




  
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    return str0[:max_len-len(str1)]+str1


  		




  31
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def split(sep, str_):


  		




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    '''Returns [] if str_ == ""'''


  		












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