Mercurial > hg
view mercurial/pure/bdiff.py @ 46924:ca0049946e9a
split: avoid strip if split is a no-op (identical to original)
Differential Revision: https://phab.mercurial-scm.org/D10389
author | Kyle Lippincott <spectral@google.com> |
---|---|
date | Mon, 12 Apr 2021 19:25:34 -0700 |
parents | d4ba4d51f85f |
children | 6000f5b25c9b |
line wrap: on
line source
# bdiff.py - Python implementation of bdiff.c # # Copyright 2009 Olivia Mackall <olivia@selenic.com> and others # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from __future__ import absolute_import import difflib import re import struct def splitnewlines(text): '''like str.splitlines, but only split on newlines.''' lines = [l + b'\n' for l in text.split(b'\n')] if lines: if lines[-1] == b'\n': lines.pop() else: lines[-1] = lines[-1][:-1] return lines def _normalizeblocks(a, b, blocks): prev = None r = [] 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 r.append((a1, b1, l1 + shift)) prev = a2 + shift, b2 + shift, l2 - shift if prev is not None: r.append(prev) return r def bdiff(a, b): a = bytes(a).splitlines(True) b = bytes(b).splitlines(True) if not a: s = b"".join(b) return s and (struct.pack(b">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 = b"".join(b[lb:bm]) if am > la or s: bin.append(struct.pack(b">lll", p[la], p[am], len(s)) + s) la = am + size lb = bm + size return b"".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] def fixws(text, allws): if allws: text = re.sub(b'[ \t\r]+', b'', text) else: text = re.sub(b'[ \t\r]+', b' ', text) text = text.replace(b' \n', b'\n') return text