def prev_n(self, position, n, start_position):
for i in range(n):
if position <= start_position:
raise EndOfString
position = rutf8.prev_codepoint_pos(self._utf8, position)
assert position >= 0
return position
def _decr(s, pos, isutf8):
if isutf8:
from rpython.rlib.rutf8 import prev_codepoint_pos
if pos <= 0:
return -1
return intmask(prev_codepoint_pos(s, pos))
else:
return pos - 1
def prev_n(self, position, n, start_position):
i = 0
# avoid range(n) since n can be quite large
while i < n:
if position <= start_position:
raise EndOfString
position = rutf8.prev_codepoint_pos(self._utf8, position)
i += 1
assert position >= 0
return position
def prev(self, position):
if position <= 0:
raise EndOfString
position = rutf8.prev_codepoint_pos(self._utf8, position)
assert position >= 0
return position