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from __future__ import annotations
from functools import lru_cache
from typing import Callable
from ._cell_widths import CELL_WIDTHS
# Ranges of unicode ordinals that produce a 1-cell wide character
# This is non-exhaustive, but covers most common Western characters
_SINGLE_CELL_UNICODE_RANGES: list[tuple[int, int]] = [
(0x20, 0x7E), # Latin (excluding non-printable)
(0xA0, 0xAC),
(0xAE, 0x002FF),
(0x00370, 0x00482), # Greek / Cyrillic
(0x02500, 0x025FC), # Box drawing, box elements, geometric shapes
(0x02800, 0x028FF), # Braille
]
# A set of characters that are a single cell wide
_SINGLE_CELLS = frozenset(
[
character
for _start, _end in _SINGLE_CELL_UNICODE_RANGES
for character in map(chr, range(_start, _end + 1))
]
)
# When called with a string this will return True if all
# characters are single-cell, otherwise False
_is_single_cell_widths: Callable[[str], bool] = _SINGLE_CELLS.issuperset
@lru_cache(4096)
def cached_cell_len(text: str) -> int:
"""Get the number of cells required to display text.
This method always caches, which may use up a lot of memory. It is recommended to use
`cell_len` over this method.
Args:
text (str): Text to display.
Returns:
int: Get the number of cells required to display text.
"""
if _is_single_cell_widths(text):
return len(text)
return sum(map(get_character_cell_size, text))
def cell_len(text: str, _cell_len: Callable[[str], int] = cached_cell_len) -> int:
"""Get the number of cells required to display text.
Args:
text (str): Text to display.
Returns:
int: Get the number of cells required to display text.
"""
if len(text) < 512:
return _cell_len(text)
if _is_single_cell_widths(text):
return len(text)
return sum(map(get_character_cell_size, text))
@lru_cache(maxsize=4096)
def get_character_cell_size(character: str) -> int:
"""Get the cell size of a character.
Args:
character (str): A single character.
Returns:
int: Number of cells (0, 1 or 2) occupied by that character.
"""
codepoint = ord(character)
_table = CELL_WIDTHS
lower_bound = 0
upper_bound = len(_table) - 1
index = (lower_bound + upper_bound) // 2
while True:
start, end, width = _table[index]
if codepoint < start:
upper_bound = index - 1
elif codepoint > end:
lower_bound = index + 1
else:
return 0 if width == -1 else width
if upper_bound < lower_bound:
break
index = (lower_bound + upper_bound) // 2
return 1
def set_cell_size(text: str, total: int) -> str:
"""Set the length of a string to fit within given number of cells."""
if _is_single_cell_widths(text):
size = len(text)
if size < total:
return text + " " * (total - size)
return text[:total]
if total <= 0:
return ""
cell_size = cell_len(text)
if cell_size == total:
return text
if cell_size < total:
return text + " " * (total - cell_size)
start = 0
end = len(text)
# Binary search until we find the right size
while True:
pos = (start + end) // 2
before = text[: pos + 1]
before_len = cell_len(before)
if before_len == total + 1 and cell_len(before[-1]) == 2:
return before[:-1] + " "
if before_len == total:
return before
if before_len > total:
end = pos
else:
start = pos
def chop_cells(
text: str,
width: int,
) -> list[str]:
"""Split text into lines such that each line fits within the available (cell) width.
Args:
text: The text to fold such that it fits in the given width.
width: The width available (number of cells).
Returns:
A list of strings such that each string in the list has cell width
less than or equal to the available width.
"""
_get_character_cell_size = get_character_cell_size
lines: list[list[str]] = [[]]
append_new_line = lines.append
append_to_last_line = lines[-1].append
total_width = 0
for character in text:
cell_width = _get_character_cell_size(character)
char_doesnt_fit = total_width + cell_width > width
if char_doesnt_fit:
append_new_line([character])
append_to_last_line = lines[-1].append
total_width = cell_width
else:
append_to_last_line(character)
total_width += cell_width
return ["".join(line) for line in lines]
if __name__ == "__main__": # pragma: no cover
print(get_character_cell_size("😽"))
for line in chop_cells("""这是对亚洲语言支持的测试。面对模棱两可的想法，拒绝猜测的诱惑。""", 8):
print(line)
for n in range(80, 1, -1):
print(set_cell_size("""这是对亚洲语言支持的测试。面对模棱两可的想法，拒绝猜测的诱惑。""", n) + "|")
print("x" * n)
|
