77 lines
2 KiB
Python
77 lines
2 KiB
Python
![]() |
# bdiff.py - Python implementation of bdiff.c
|
||
|
#
|
||
|
# Copyright 2009 Matt Mackall <mpm@selenic.com> and others
|
||
|
#
|
||
|
# This software may be used and distributed according to the terms of the
|
||
|
# GNU General Public License version 2, incorporated herein by reference.
|
||
|
|
||
|
import struct, difflib
|
||
|
|
||
|
def splitnewlines(text):
|
||
|
'''like str.splitlines, but only split on newlines.'''
|
||
|
lines = [l + '\n' for l in text.split('\n')]
|
||
|
if lines:
|
||
|
if lines[-1] == '\n':
|
||
|
lines.pop()
|
||
|
else:
|
||
|
lines[-1] = lines[-1][:-1]
|
||
|
return lines
|
||
|
|
||
|
def _normalizeblocks(a, b, blocks):
|
||
|
prev = None
|
||
|
for curr in blocks:
|
||
|
if prev is None:
|
||
|
prev = curr
|
||
|
continue
|
||
|
shift = 0
|
||
|
|
||
|
a1, b1, l1 = prev
|
||
|
a1end = a1 + l1
|
||
|
b1end = b1 + l1
|
||
|
|
||
|
a2, b2, l2 = curr
|
||
|
a2end = a2 + l2
|
||
|
b2end = b2 + l2
|
||
|
if a1end == a2:
|
||
|
while a1end+shift < a2end and a[a1end+shift] == b[b1end+shift]:
|
||
|
shift += 1
|
||
|
elif b1end == b2:
|
||
|
while b1end+shift < b2end and a[a1end+shift] == b[b1end+shift]:
|
||
|
shift += 1
|
||
|
yield a1, b1, l1+shift
|
||
|
prev = a2+shift, b2+shift, l2-shift
|
||
|
yield prev
|
||
|
|
||
|
def bdiff(a, b):
|
||
|
a = str(a).splitlines(True)
|
||
|
b = str(b).splitlines(True)
|
||
|
|
||
|
if not a:
|
||
|
s = "".join(b)
|
||
|
return s and (struct.pack(">lll", 0, 0, len(s)) + s)
|
||
|
|
||
|
bin = []
|
||
|
p = [0]
|
||
|
for i in a: p.append(p[-1] + len(i))
|
||
|
|
||
|
d = difflib.SequenceMatcher(None, a, b).get_matching_blocks()
|
||
|
d = _normalizeblocks(a, b, d)
|
||
|
la = 0
|
||
|
lb = 0
|
||
|
for am, bm, size in d:
|
||
|
s = "".join(b[lb:bm])
|
||
|
if am > la or s:
|
||
|
bin.append(struct.pack(">lll", p[la], p[am], len(s)) + s)
|
||
|
la = am + size
|
||
|
lb = bm + size
|
||
|
|
||
|
return "".join(bin)
|
||
|
|
||
|
def blocks(a, b):
|
||
|
an = splitnewlines(a)
|
||
|
bn = splitnewlines(b)
|
||
|
d = difflib.SequenceMatcher(None, an, bn).get_matching_blocks()
|
||
|
d = _normalizeblocks(an, bn, d)
|
||
|
return [(i, i + n, j, j + n) for (i, j, n) in d]
|
||
|
|