def split_contigous_intervals_for_surrogates(Begin, End):
"""Splits the interval X into sub interval so that no interval runs over a 'surrogate'
border of the last word. For that, it is simply checked if the End falls into the
same 'surrogate' domain of 'front' (start value of front = Begin). If it does not
an interval [front, end_of_domain) is split up and front is set to end of domain.
This procedure repeats until front and End lie in the same domain.
"""
assert Begin >= 0x10000
assert End <= 0x110000
front_seq = unicode_to_utf16(Begin)
back_seq = unicode_to_utf16(End - 1)
if front_seq[0] == back_seq[0]:
return [Interval(Begin, End)]
# Separate into three domains:
#
# (1) interval from Begin until second surrogate hits border 0xE000
# (2) interval where the first surrogate inreases while second
# surrogate iterates over [0xDC00, 0xDFFF]
# (3) interval from begin of last surrogate border to End
result = []
end = utf16_to_unicode([front_seq[0], 0xDFFF]) + 1
# The following **must** hold according to entry condition about front and back sequence
assert End > end
result.append(Interval(Begin, end))
if front_seq[0] + 1 != back_seq[0]:
mid_end = utf16_to_unicode([back_seq[0] - 1, 0xDFFF]) + 1
result.append(Interval(end, mid_end))
end = mid_end
result.append(Interval(end, End))
return result
def get_trigger_sequence_for_interval(X):
# The interval either lies entirely >= 0x10000 or entirely < 0x10000
assert X.begin >= 0x10000 or X.end < 0x10000
# An interval below < 0x10000 remains the same
if X.end < 0x10000: return [ X ]
# In case that the interval >= 0x10000 it the value is split up into
# two values.
front_seq = unicode_to_utf16(X.begin)
back_seq = unicode_to_utf16(X.end - 1)
return [ Interval(front_seq[0], back_seq[0] + 1),
Interval(front_seq[1], back_seq[1] + 1) ]