1414# some Unicode spaces (like \u00a0) are non-breaking whitespaces.
1515_whitespace = '\t \n \x0b \x0c \r '
1616
17+ try :
18+ from unicodedata import east_asian_width
19+
20+ def _width (text ):
21+ """Return the display width of the text in columns, according to
22+ unicodedata.east_asian_width only.
23+ """
24+ return sum (2 if east_asian_width (char ) in {'F' , 'W' } else 1
25+ for char in text )
26+
27+ def _slice (text , index ):
28+ """Return the two slices of text cut to index.
29+ """
30+ width = 0
31+ pos = 0
32+ for char in text :
33+ width += 2 if east_asian_width (char ) in {'F' , 'W' } else 1
34+ if width > index :
35+ break
36+ pos += 1
37+ return text [:pos ], text [pos :]
38+
39+ except ImportError :
40+
41+ def _width (text ):
42+ """Fallback in case unicodedata is not available: The display width of
43+ a text is just its number of characters.
44+ """
45+ return len (text )
46+
47+ def _slice (text , index ):
48+ return text [:index ], text [index :]
49+
50+
1751class TextWrapper :
1852 """
1953 Object for wrapping/filling text. The public interface consists of
@@ -215,8 +249,9 @@ def _handle_long_word(self, reversed_chunks, cur_line, cur_len, width):
215249 # If we're allowed to break long words, then do so: put as much
216250 # of the next chunk onto the current line as will fit.
217251 if self .break_long_words :
218- cur_line .append (reversed_chunks [- 1 ][:space_left ])
219- reversed_chunks [- 1 ] = reversed_chunks [- 1 ][space_left :]
252+ left , right = _slice (reversed_chunks [- 1 ], space_left )
253+ cur_line .append (left )
254+ reversed_chunks [- 1 ] = right
220255
221256 # Otherwise, we have to preserve the long word intact. Only add
222257 # it to the current line if there's nothing already there --
@@ -244,14 +279,13 @@ def _wrap_chunks(self, chunks):
244279 lines, but apart from that whitespace is preserved.
245280 """
246281 lines = []
247- if self .width <= 0 :
248- raise ValueError ("invalid width %r (must be > 0)" % self .width )
249282 if self .max_lines is not None :
250283 if self .max_lines > 1 :
251284 indent = self .subsequent_indent
252285 else :
253286 indent = self .initial_indent
254- if len (indent ) + len (self .placeholder .lstrip ()) > self .width :
287+ if (_width (indent ) +
288+ _width (self .placeholder .lstrip ()) > self .width ):
255289 raise ValueError ("placeholder too large for max width" )
256290
257291 # Arrange in reverse order so items can be efficiently popped
@@ -272,15 +306,15 @@ def _wrap_chunks(self, chunks):
272306 indent = self .initial_indent
273307
274308 # Maximum width for this line.
275- width = self .width - len (indent )
309+ width = self .width - _width (indent )
276310
277311 # First chunk on line is whitespace -- drop it, unless this
278312 # is the very beginning of the text (ie. no lines started yet).
279313 if self .drop_whitespace and chunks [- 1 ].strip () == '' and lines :
280314 del chunks [- 1 ]
281315
282316 while chunks :
283- l = len (chunks [- 1 ])
317+ l = _width (chunks [- 1 ])
284318
285319 # Can at least squeeze this chunk onto the current line.
286320 if cur_len + l <= width :
@@ -290,16 +324,15 @@ def _wrap_chunks(self, chunks):
290324 # Nope, this line is full.
291325 else :
292326 break
293-
294327 # The current line is full, and the next chunk is too big to
295328 # fit on *any* line (not just this one).
296- if chunks and len (chunks [- 1 ]) > width :
329+ if chunks and _width (chunks [- 1 ]) > width :
297330 self ._handle_long_word (chunks , cur_line , cur_len , width )
298- cur_len = sum (map (len , cur_line ))
331+ cur_len = sum (map (_width , cur_line ))
299332
300333 # If the last chunk on this line is all whitespace, drop it.
301334 if self .drop_whitespace and cur_line and cur_line [- 1 ].strip () == '' :
302- cur_len -= len (cur_line [- 1 ])
335+ cur_len -= _width (cur_line [- 1 ])
303336 del cur_line [- 1 ]
304337
305338 if cur_line :
@@ -315,17 +348,17 @@ def _wrap_chunks(self, chunks):
315348 else :
316349 while cur_line :
317350 if (cur_line [- 1 ].strip () and
318- cur_len + len (self .placeholder ) <= width ):
351+ cur_len + _width (self .placeholder ) <= width ):
319352 cur_line .append (self .placeholder )
320353 lines .append (indent + '' .join (cur_line ))
321354 break
322- cur_len -= len (cur_line [- 1 ])
355+ cur_len -= _width (cur_line [- 1 ])
323356 del cur_line [- 1 ]
324357 else :
325358 if lines :
326359 prev_line = lines [- 1 ].rstrip ()
327- if (len (prev_line ) + len ( self . placeholder ) <=
328- self .width ):
360+ if (_width (prev_line ) +
361+ _width ( self . placeholder ) <= self .width ):
329362 lines [- 1 ] = prev_line + self .placeholder
330363 break
331364 lines .append (indent + self .placeholder .lstrip ())
@@ -348,6 +381,10 @@ def wrap(self, text):
348381 and all other whitespace characters (including newline) are
349382 converted to space.
350383 """
384+ if self .width <= 0 :
385+ raise ValueError ("invalid width %r (must be > 0)" % self .width )
386+ elif self .width == 1 and _width (text ) > len (text ):
387+ raise ValueError ("invalid width 1 (must be > 1 when CJK chars)" )
351388 chunks = self ._split_chunks (text )
352389 if self .fix_sentence_endings :
353390 self ._fix_sentence_endings (chunks )
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