##// END OF EJS Templates
bdiff: don't check border condition in loop...
bdiff: don't check border condition in loop `plast = a + len - 1`. So, this "for" loop iterates from "a" to "plast", inclusive. So, `p == plast` can only be true on the final iteration of the loop. So checking for it on every loop iteration is wasteful. This patch simply decreases the upper bound of the loop by 1 and adds an explicit check after iteration for the `p == plast` case. We can't simply add 1 to the initial value for "i" because that doesn't do the correct thing on empty input strings. `perfbdiff -m 3041e4d59df2` on the Firefox repo becomes significantly faster: ! wall 0.072763 comb 0.070000 user 0.070000 sys 0.000000 (best of 100) ! wall 0.053221 comb 0.060000 user 0.060000 sys 0.000000 (best of 100) For the curious, this code has its origins in 8b067bde6679, which is the changeset that introduced bdiff.c in 2005. Also, GNU diffutils is able to perform a similar line-based diff in under 20ms. So there's likely more perf wins to be found in this code. One of them is the hashing algorithm. But it looks like mpm spent some time testing hash collisions in d0c48891dd4a. I'd like to do the same before switching away from lyhash, just to be on the safe side.

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py3kcompat.py
68 lines | 2.1 KiB | text/x-python | PythonLexer
# py3kcompat.py - compatibility definitions for running hg in py3k
#
# Copyright 2010 Renato Cunha <renatoc@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
import builtins
import numbers
Number = numbers.Number
def bytesformatter(format, args):
'''Custom implementation of a formatter for bytestrings.
This function currently relies on the string formatter to do the
formatting and always returns bytes objects.
>>> bytesformatter(20, 10)
0
>>> bytesformatter('unicode %s, %s!', ('string', 'foo'))
b'unicode string, foo!'
>>> bytesformatter(b'test %s', 'me')
b'test me'
>>> bytesformatter('test %s', 'me')
b'test me'
>>> bytesformatter(b'test %s', b'me')
b'test me'
>>> bytesformatter('test %s', b'me')
b'test me'
>>> bytesformatter('test %d: %s', (1, b'result'))
b'test 1: result'
'''
# The current implementation just converts from bytes to unicode, do
# what's needed and then convert the results back to bytes.
# Another alternative is to use the Python C API implementation.
if isinstance(format, Number):
# If the fixer erroneously passes a number remainder operation to
# bytesformatter, we just return the correct operation
return format % args
if isinstance(format, bytes):
format = format.decode('utf-8', 'surrogateescape')
if isinstance(args, bytes):
args = args.decode('utf-8', 'surrogateescape')
if isinstance(args, tuple):
newargs = []
for arg in args:
if isinstance(arg, bytes):
arg = arg.decode('utf-8', 'surrogateescape')
newargs.append(arg)
args = tuple(newargs)
ret = format % args
return ret.encode('utf-8', 'surrogateescape')
builtins.bytesformatter = bytesformatter
origord = builtins.ord
def fakeord(char):
if isinstance(char, int):
return char
return origord(char)
builtins.ord = fakeord
if __name__ == '__main__':
import doctest
doctest.testmod()