Mercurial > hg
view mercurial/cffi/mpatch.py @ 46099:fd75e5c53ec3
simplemerge: avoid quadratic concatenation when building output text
I haven't checked if the difference is measurable, but the new version
is no less readable or idiomatic, so I don't think performance numbers
are needed.
Differential Revision: https://phab.mercurial-scm.org/D9549
author | Martin von Zweigbergk <martinvonz@google.com> |
---|---|
date | Tue, 08 Dec 2020 23:05:53 -0800 |
parents | 687b865b95ad |
children | 521ac0d7047f |
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# mpatch.py - CFFI implementation of mpatch.c # # Copyright 2016 Maciej Fijalkowski <fijall@gmail.com> # # 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 from ..pure.mpatch import * from ..pure.mpatch import mpatchError # silence pyflakes from . import _mpatch ffi = _mpatch.ffi lib = _mpatch.lib @ffi.def_extern() def cffi_get_next_item(arg, pos): all, bins = ffi.from_handle(arg) container = ffi.new(b"struct mpatch_flist*[1]") to_pass = ffi.new(b"char[]", str(bins[pos])) all.append(to_pass) r = lib.mpatch_decode(to_pass, len(to_pass) - 1, container) if r < 0: return ffi.NULL return container[0] def patches(text, bins): lgt = len(bins) all = [] if not lgt: return text arg = (all, bins) patch = lib.mpatch_fold(ffi.new_handle(arg), lib.cffi_get_next_item, 0, lgt) if not patch: raise mpatchError(b"cannot decode chunk") outlen = lib.mpatch_calcsize(len(text), patch) if outlen < 0: lib.mpatch_lfree(patch) raise mpatchError(b"inconsistency detected") buf = ffi.new(b"char[]", outlen) if lib.mpatch_apply(buf, text, len(text), patch) < 0: lib.mpatch_lfree(patch) raise mpatchError(b"error applying patches") res = ffi.buffer(buf, outlen)[:] lib.mpatch_lfree(patch) return res