56 lines
1.2 KiB
Python
56 lines
1.2 KiB
Python
import unicodedata
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from functools import lru_cache
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@lru_cache(100)
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def wcwidth(c: str) -> int:
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"""Determine how many columns are needed to display a character in a terminal.
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Returns -1 if the character is not printable.
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Returns 0, 1 or 2 for other characters.
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"""
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o = ord(c)
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# ASCII fast path.
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if 0x20 <= o < 0x07F:
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return 1
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# Some Cf/Zp/Zl characters which should be zero-width.
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if (
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o == 0x0000
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or 0x200B <= o <= 0x200F
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or 0x2028 <= o <= 0x202E
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or 0x2060 <= o <= 0x2063
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):
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return 0
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category = unicodedata.category(c)
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# Control characters.
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if category == "Cc":
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return -1
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# Combining characters with zero width.
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if category in ("Me", "Mn"):
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return 0
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# Full/Wide east asian characters.
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if unicodedata.east_asian_width(c) in ("F", "W"):
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return 2
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return 1
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def wcswidth(s: str) -> int:
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"""Determine how many columns are needed to display a string in a terminal.
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Returns -1 if the string contains non-printable characters.
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"""
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width = 0
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for c in unicodedata.normalize("NFC", s):
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wc = wcwidth(c)
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if wc < 0:
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return -1
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width += wc
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return width
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