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# Copyright 2017 Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>
#
# This file is part of Poezio.
#
# Poezio is free software: you can redistribute it and/or modify
# it under the terms of the zlib license. See the COPYING file.
'''This is a template module just for instruction. And poopt.'''
from typing import List, Tuple
# CFFI codepath.
from cffi import FFI
ffi = FFI()
ffi.cdef("""
typedef long wchar_t;
int wcwidth(wchar_t c);
""")
libc = ffi.dlopen(None)
# Cython codepath.
#cdef extern from "wchar.h":
# ctypedef Py_UCS4 wchar_t
# int wcwidth(wchar_t c)
# Just checking if the return value is -1. In some (all?) implementations,
# wcwidth("😆") returns -1 while it should return 1. In these cases, we
# return 1 instead because this is by far the most probable real value.
# Since the string is received from python, and the unicode character is
# extracted with mbrtowc(), and supposing these two compononents are not
# bugged, and since poezio’s code should never pass '\t', '\n' or their
# friends, a return value of -1 from wcwidth() is considered to be a bug in
# wcwidth() (until proven otherwise). xwcwidth() is here to work around
# this bug.
def xwcwidth(c: str) -> int:
character = ord(c)
res = libc.wcwidth(character)
if res == -1 and c != '\x19':
return 1
return res
# cut_text: takes a string and returns a tuple of int.
#
# Each two int tuple is a line, represented by the ending position it
# (where it should be cut). Not that this position is calculed using the
# position of the python string characters, not just the individual bytes.
#
# For example,
# poopt_cut_text("vivent les réfrigérateurs", 6);
# will return [(0, 6), (7, 10), (11, 17), (17, 22), (22, 24)], meaning that
# the lines are
# "vivent", "les", "réfrig", "érateu" and "rs"
def cut_text(string: str, width: int) -> List[Tuple[int, int]]:
'''cut_text(text, width)
Return a list of two-tuple, the first int is the starting position of the line and the second is its end.'''
# The list of tuples that we return
retlist = []
# The start position (in the python-string) of the next line
#: unsigned int
start_pos = 0
# The position of the last space seen in the current line. This is used
# to cut on spaces instead of cutting inside words, if possible (aka if
# there is a space)
#: int
last_space = -1
# The number of columns taken by chars between start_pos and last_space
#: size_t
cols_until_space = 0
# Number of columns taken to display the current line so far
#: size_t
columns = 0
#: wchar_t
#wc = 0
# The position, considering unicode chars (aka, the position in the
# python string). This is used to determine the position in the python
# string at which we should cut */
#: unsigned int
#spos = -1
in_special_character = False
for spos, wc in enumerate(string):
# Special case to skip poezio special characters that are contained
# in the python string, but should not be counted as chars because
# they will not be displayed. Those are the formatting chars (to
# insert colors or things like that in the string)
if in_special_character:
# Skip everything until the end of this format marker, but
# without increasing the number of columns of the current
# line. Because these chars are not printed.
if wc in ('u', 'a', 'i', 'b', 'o', '}'):
in_special_character = False
continue
if wc == '\x19':
in_special_character = True
continue
# This is one condition to end the line: an explicit \n is found
if wc == '\n':
spos += 1
retlist.append((start_pos, spos))
# And then initiate a new line
start_pos = spos
last_space = -1
columns = 0
continue
# Get the number of columns needed to display this character. May be 0, 1 or 2
cols = xwcwidth(wc)
# This is the second condition to end the line: we have consumed
# enough columns to fill a whole line
if columns + cols > width:
# If possible, cut on a space
if last_space != -1:
retlist.append((start_pos, last_space))
start_pos = last_space + 1
last_space = -1
columns -= (cols_until_space + 1)
else:
# Otherwise, cut in the middle of a word
retlist.append((start_pos, spos))
start_pos = spos
columns = 0
# We save the position of the last space seen in this line, and the
# number of columns we have until now. This helps us keep track of
# the columns to count when we will use that space as a cutting
# point, later
if wc == ' ':
last_space = spos
cols_until_space = columns
# We advanced from one char, increment spos by one and add the
# char's columns to the line's columns
columns += cols
# We are at the end of the string, append the last line, not finished
retlist.append((start_pos, spos + 1))
return retlist
# wcswidth: An emulation of the POSIX wcswidth(3) function using xwcwidth.
def wcswidth(string: str) -> int:
'''wcswidth(s)
The wcswidth() function returns the number of columns needed to represent the wide-character string pointed to by s. Raise UnicodeError if an invalid unicode value is passed'''
columns = 0
for wc in string:
columns += xwcwidth(wc)
return columns
# cut_by_columns: takes a python string and a number of columns, returns a
# python string truncated to take at most that many columns
# For example cut_by_columns(n, "エメルカ") will return:
# - n == 5 -> "エメ" (which takes only 4 columns since we can't cut the
# next character in half)
# - n == 2 -> "エ"
# - n == 1 -> ""
# - n == 42 -> "エメルカ"
# - etc
def cut_by_columns(string: str, limit: int) -> str:
'''cut_by_columns(string, limit)
returns a string truncated to take at most limit columns'''
spos = 0
columns = 0
for wc in string:
if columns == limit:
break
cols = xwcwidth(wc)
if columns + cols > limit:
break
spos += 1
columns += cols
return string[:spos]
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