bdiff: don't check border condition in loop
This is pretty much a copy of d500ddae7494, just to a different loop.
The condition `p == plast` (`plast == a + len - 1`) was only true on
the final iteration of the loop. So it was wasteful to check for it
on every iteration. We decrease the iteration count by 1 and add an
explicit check for `p == plast` after the loop.
Again, we see modest wins.
From the mozilla-unified repository:
$ perfbdiff -m 3041e4d59df2
! wall 0.035502 comb 0.040000 user 0.040000 sys 0.000000 (best of 100)
! wall 0.030480 comb 0.030000 user 0.030000 sys 0.000000 (best of 100)
$ perfbdiff 0e9928989e9c --alldata --count 100
! wall 4.097394 comb 4.100000 user 4.100000 sys 0.000000 (best of 3)
! wall 3.597798 comb 3.600000 user 3.600000 sys 0.000000 (best of 3)
The 2nd example throws a total of ~3.3GB of data at bdiff. This
change increases the throughput from ~811 MB/s to ~924 MB/s.
# 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()