352 lines
9.9 KiB
Python
352 lines
9.9 KiB
Python
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class BaseStemmer(object):
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def __init__(self):
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self.set_current("")
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self.maxCacheSize = 10000
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self._cache = {}
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self._counter = 0
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def set_current(self, value):
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'''
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Set the self.current string.
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'''
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self.current = value
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self.cursor = 0
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self.limit = len(self.current)
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self.limit_backward = 0
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self.bra = self.cursor
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self.ket = self.limit
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def get_current(self):
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'''
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Get the self.current string.
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'''
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return self.current
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def copy_from(self, other):
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self.current = other.current
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self.cursor = other.cursor
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self.limit = other.limit
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self.limit_backward = other.limit_backward
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self.bra = other.bra
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self.ket = other.ket
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def in_grouping(self, s, min, max):
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if self.cursor >= self.limit:
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return False
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ch = ord(self.current[self.cursor])
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if ch > max or ch < min:
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return False
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ch -= min
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if (s[ch >> 3] & (0x1 << (ch & 0x7))) == 0:
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return False
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self.cursor += 1
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return True
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def in_grouping_b(self, s, min, max):
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if self.cursor <= self.limit_backward:
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return False
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ch = ord(self.current[self.cursor - 1])
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if ch > max or ch < min:
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return False
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ch -= min
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if (s[ch >> 3] & (0x1 << (ch & 0x7))) == 0:
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return False
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self.cursor -= 1
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return True
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def out_grouping(self, s, min, max):
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if self.cursor >= self.limit:
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return False
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ch = ord(self.current[self.cursor])
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if ch > max or ch < min:
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self.cursor += 1
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return True
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ch -= min
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if (s[ch >> 3] & (0X1 << (ch & 0x7))) == 0:
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self.cursor += 1
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return True
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return False
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def out_grouping_b(self, s, min, max):
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if self.cursor <= self.limit_backward:
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return False
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ch = ord(self.current[self.cursor - 1])
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if ch > max or ch < min:
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self.cursor -= 1
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return True
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ch -= min
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if (s[ch >> 3] & (0X1 << (ch & 0x7))) == 0:
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self.cursor -= 1
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return True
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return False
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def in_range(self, min, max):
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if self.cursor >= self.limit:
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return False
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ch = ord(self.current[self.cursor])
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if ch > max or ch < min:
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return False
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self.cursor += 1
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return True
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def in_range_b(self, min, max):
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if self.cursor <= self.limit_backward:
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return False
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ch = ord(self.current[self.cursor - 1])
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if ch > max or ch < min:
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return False
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self.cursor -= 1
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return True
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def out_range(self, min, max):
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if self.cursor >= self.limit:
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return False
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ch = ord(self.current[self.cursor])
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if not (ch > max or ch < min):
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return False
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self.cursor += 1
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return True
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def out_range_b(self, min, max):
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if self.cursor <= self.limit_backward:
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return False
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ch = ord(self.current[self.cursor - 1])
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if not (ch > max or ch < min):
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return False
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self.cursor -= 1
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return True
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def eq_s(self, s_size, s):
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if self.limit - self.cursor < s_size:
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return False
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if self.current[self.cursor:self.cursor + s_size] != s:
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return False
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self.cursor += s_size
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return True
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def eq_s_b(self, s_size, s):
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if self.cursor - self.limit_backward < s_size:
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return False
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if self.current[self.cursor - s_size:self.cursor] != s:
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return False
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self.cursor -= s_size
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return True
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def eq_v(self, s):
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return self.eq_s(len(s), s)
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def eq_v_b(self, s):
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return self.eq_s_b(len(s), s)
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def find_among(self, v, v_size):
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i = 0
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j = v_size
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c = self.cursor
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l = self.limit
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common_i = 0
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common_j = 0
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first_key_inspected = False
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while True:
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k = i + ((j - i) >> 1)
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diff = 0
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common = min(common_i, common_j) # smalle
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w = v[k]
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for i2 in range(common, w.s_size):
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if c + common == l:
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diff = -1
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break
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diff = ord(self.current[c + common]) - ord(w.s[i2])
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if diff != 0:
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break
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common += 1
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if diff < 0:
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j = k
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common_j = common
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else:
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i = k
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common_i = common
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if j - i <= 1:
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if i > 0:
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break # v->s has been inspected
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if j == i:
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break # only one item in v
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# - but now we need to go round once more to get
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# v->s inspected. self looks messy, but is actually
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# the optimal approach.
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if first_key_inspected:
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break
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first_key_inspected = True
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while True:
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w = v[i]
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if common_i >= w.s_size:
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self.cursor = c + w.s_size
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if w.method is None:
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return w.result
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method = getattr(self, w.method)
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res = method()
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self.cursor = c + w.s_size
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if res:
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return w.result
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i = w.substring_i
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if i < 0:
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return 0
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return -1 # not reachable
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def find_among_b(self, v, v_size):
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'''
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find_among_b is for backwards processing. Same comments apply
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'''
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i = 0
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j = v_size
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c = self.cursor
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lb = self.limit_backward;
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common_i = 0
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common_j = 0
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first_key_inspected = False
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while True:
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k = i + ((j - i) >> 1)
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diff = 0
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common = min(common_i, common_j)
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w = v[k]
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for i2 in range(w.s_size - 1 - common, -1, -1):
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if c - common == lb:
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diff = -1
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break
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diff = ord(self.current[c - 1 - common]) - ord(w.s[i2])
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if diff != 0:
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break
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common += 1
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if diff < 0:
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j = k
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common_j = common
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else:
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i = k
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common_i = common
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if j - i <= 1:
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if i > 0:
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break
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if j == i:
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break
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if first_key_inspected:
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break
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first_key_inspected = True
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while True:
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w = v[i]
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if common_i >= w.s_size:
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self.cursor = c - w.s_size
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if w.method is None:
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return w.result
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method = getattr(self, w.method)
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res = method()
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self.cursor = c - w.s_size
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if res:
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return w.result
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i = w.substring_i
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if i < 0:
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return 0
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return -1 # not reachable
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def replace_s(self, c_bra, c_ket, s):
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'''
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to replace chars between c_bra and c_ket in self.current by the
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chars in s.
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@type c_bra int
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@type c_ket int
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@type s: string
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'''
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adjustment = len(s) - (c_ket - c_bra)
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self.current = self.current[0:c_bra] + s + self.current[c_ket:]
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self.limit += adjustment
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if self.cursor >= c_ket:
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self.cursor += adjustment
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elif self.cursor > c_bra:
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self.cursor = c_bra
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return adjustment
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def slice_check(self):
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if self.bra < 0 or self.bra > self.ket or self.ket > self.limit or self.limit > len(self.current):
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return False
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return True
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def slice_from(self, s):
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'''
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@type s string
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'''
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result = False
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if self.slice_check():
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self.replace_s(self.bra, self.ket, s)
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result = True
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return result
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def slice_del(self):
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return self.slice_from("")
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def insert(self, c_bra, c_ket, s):
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'''
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@type c_bra int
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@type c_ket int
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@type s: string
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'''
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adjustment = self.replace_s(c_bra, c_ket, s)
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if c_bra <= self.bra:
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self.bra += adjustment
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if c_bra <= self.ket:
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self.ket += adjustment
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def slice_to(self, s):
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'''
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Copy the slice into the supplied StringBuffer
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@type s: string
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'''
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result = ''
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if self.slice_check():
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result = self.current[self.bra:self.ket]
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return result
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def assign_to(self, s):
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'''
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@type s: string
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'''
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return self.current[0:self.limit]
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def _stem_word(self, word):
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cache = self._cache.get(word)
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if cache is None:
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self.set_current(word)
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self._stem()
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result = self.get_current()
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self._cache[word] = [result, self._counter]
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else:
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cache[1] = self._counter
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result = cache[0]
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self._counter += 1
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return result
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def _clear_cache(self):
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removecount = int(len(self._cache) - self.maxCacheSize * 8 / 10)
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oldcaches = sorted(self._cache.items(), key=lambda cache: cache[1][1])[0:removecount]
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for key, value in oldcaches:
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del self._cache[key]
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def stemWord(self, word):
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result = self._stem_word(word)
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if len(self._cache) > self.maxCacheSize:
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self._clear_cache()
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return result
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def stemWords(self, words):
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result = [self._stem_word(word) for word in words]
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if len(self._cache) > self.maxCacheSize:
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self._clear_cache()
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return result
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