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# -*- coding: iso-8859-1 -*-
"""
MoinMoin - diff3 algorithm
@copyright: 2002 Florian Festi
@license: GNU GPL, see COPYING for details.
"""
default_markers = ('<<<<<<<<<<<<<<<<<<<<<<<<<\n',
'=========================\n',
'>>>>>>>>>>>>>>>>>>>>>>>>>\n')
def text_merge(old, other, new, allow_conflicts=1, *markers):
""" do line by line diff3 merge with three strings """
result = merge(old.splitlines(1), other.splitlines(1), new.splitlines(1),
allow_conflicts, *markers)
return ''.join(result)
def merge(old, other, new, allow_conflicts=1, *markers):
""" do line by line diff3 merge
input must be lists containing single lines
"""
if not markers:
markers = default_markers
marker1, marker2, marker3 = markers
old_nr, other_nr, new_nr = 0, 0, 0
old_len, other_len, new_len = len(old), len(other), len(new)
result = []
while old_nr < old_len and other_nr < other_len and new_nr < new_len:
# unchanged
if old[old_nr] == other[other_nr] == new[new_nr]:
result.append(old[old_nr])
old_nr += 1
other_nr += 1
new_nr += 1
else:
if allow_conflicts == 2: # experimental addition to the algorithm
if other[other_nr] == new[new_nr]:
result.append(new[new_nr])
other_nr += 1
new_nr += 1
continue
new_match = find_match(old, new, old_nr, new_nr)
other_match = find_match(old, other, old_nr, other_nr)
# new is changed
if new_match != (old_nr, new_nr):
new_changed_lines = new_match[0] - old_nr
# other is unchanged
if match(old, other, old_nr, other_nr,
new_changed_lines) == new_changed_lines:
result.extend(new[new_nr:new_match[1]])
old_nr = new_match[0]
new_nr = new_match[1]
other_nr += new_changed_lines
# both changed, conflict!
else:
if not allow_conflicts:
return None
old_m, other_m, new_m = tripple_match(
old, other, new, other_match, new_match)
result.append(marker1)
result.extend(other[other_nr:other_m])
result.append(marker2)
result.extend(new[new_nr:new_m])
result.append(marker3)
old_nr, other_nr, new_nr = old_m, other_m, new_m
# other is changed
else:
other_changed_lines = other_match[0] - other_nr
# new is unchanged
if match(old, new, old_nr, new_nr,
other_changed_lines) == other_changed_lines:
result.extend(other[other_nr:other_match[1]])
old_nr = other_match[0]
other_nr = other_match[1]
new_nr += other_changed_lines
# both changed, conflict!
else:
if not allow_conflicts:
return None
old_m, other_m, new_m = tripple_match(
old, other, new, other_match, new_match)
result.append(marker1)
result.extend(other[other_nr:other_m])
result.append(marker2)
result.extend(new[new_nr:new_m])
result.append(marker3)
old_nr, other_nr, new_nr = old_m, other_m, new_m
# process tail
# all finished
if old_nr == old_len and other_nr == other_len and new_nr == new_len:
pass
# new added lines
elif old_nr == old_len and other_nr == other_len:
result.extend(new[new_nr:])
# other added lines
elif old_nr == old_len and new_nr == new_len:
result.extend(other[other_nr:])
# new deleted lines
elif (new_nr == new_len and (old_len - old_nr == other_len - other_nr) and
match(old, other, old_nr, other_nr, old_len-old_nr) == old_len - old_nr):
pass
# other deleted lines
elif (other_nr == other_len and (old_len - old_nr == new_len-new_nr) and
match(old, new, old_nr, new_nr, old_len-old_nr) == old_len - old_nr):
pass
# conflict
else:
if new == other:
result.extend(new[new_nr:])
else:
if not allow_conflicts:
return None
result.append(marker1)
result.extend(other[other_nr:])
result.append(marker2)
result.extend(new[new_nr:])
result.append(marker3)
return result
def tripple_match(old, other, new, other_match, new_match):
"""find next matching pattern unchanged in both other and new
return the position in all three lists
"""
while 1:
difference = new_match[0] - other_match[0]
# new changed more lines
if difference > 0:
match_len = match(old, other, other_match[0], other_match[1],
difference)
if match_len == difference:
return (new_match[0], other_match[1]+difference, new_match[1])
else:
other_match = find_match(old, other,
other_match[0] + match_len,
other_match[1] + match_len)
# other changed more lines
elif difference < 0:
difference = -difference
match_len = match(old, new, new_match[0], new_match[1],
difference)
if match_len == difference:
return (other_match[0], other_match[1],
new_match[0] + difference)
else:
new_match = find_match(old, new,
new_match[0] + match_len,
new_match[1] + match_len)
# both conflicts change same number of lines
# or no match till the end
else:
return (new_match[0], other_match[1], new_match[1])
def match(list1, list2, nr1, nr2, maxcount=3):
""" return the number matching items after the given positions
maximum maxcount lines are are processed
"""
i = 0
len1 = len(list1)
len2 = len(list2)
while nr1 < len1 and nr2 < len2 and list1[nr1] == list2[nr2]:
nr1 += 1
nr2 += 1
i += 1
if i >= maxcount and maxcount > 0:
break
return i
def find_match(list1, list2, nr1, nr2, mincount=3):
"""searches next matching pattern with lenght mincount
if no pattern is found len of the both lists is returned
"""
len1 = len(list1)
len2 = len(list2)
hit1 = None
hit2 = None
idx1 = nr1
idx2 = nr2
while (idx1 < len1) or (idx2 < len2):
i = nr1
while i <= idx1:
hit_count = match(list1, list2, i, idx2, mincount)
if hit_count >= mincount:
hit1 = (i, idx2)
break
i += 1
i = nr2
while i < idx2:
hit_count = match(list1, list2, idx1, i, mincount)
if hit_count >= mincount:
hit2 = (idx1, i)
break
i += 1
if hit1 or hit2:
break
if idx1 < len1:
idx1 += 1
if idx2 < len2:
idx2 += 1
if hit1 and hit2:
#XXX which one?
return hit1
elif hit1:
return hit1
elif hit2:
return hit2
else:
return (len1, len2)
def main():
text0 = """AAA 001
AAA 002
AAA 003
AAA 004
AAA 005
AAA 006
AAA 007
AAA 008
AAA 009
AAA 010
AAA 011
AAA 012
AAA 013
AAA 014
"""
text1 = """AAA 001
AAA 002
AAA 005
AAA 006
AAA 007
AAA 008
BBB 001
BBB 002
AAA 009
AAA 010
BBB 003
"""
text2 = """AAA 001
AAA 002
AAA 003
AAA 004
AAA 005
AAA 006
AAA 007
AAA 008
CCC 001
CCC 002
CCC 003
AAA 012
AAA 013
AAA 014
"""
text = text_merge(text0, text1, text2)
print(text)
if __name__ == '__main__':
main()
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