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.
$ unset HGUSER
$ EMAIL="My Name <myname@example.com>"
$ export EMAIL
$ hg init test
$ cd test
$ touch asdf
$ hg add asdf
$ hg commit -m commit-1
$ hg tip
changeset: 0:53f268a58230
tag: tip
user: My Name <myname@example.com>
date: Thu Jan 01 00:00:00 1970 +0000
summary: commit-1
$ unset EMAIL
$ echo 1234 > asdf
$ hg commit -u "foo@bar.com" -m commit-1
$ hg tip
changeset: 1:3871b2a9e9bf
tag: tip
user: foo@bar.com
date: Thu Jan 01 00:00:00 1970 +0000
summary: commit-1
$ echo "[ui]" >> .hg/hgrc
$ echo "username = foobar <foo@bar.com>" >> .hg/hgrc
$ echo 12 > asdf
$ hg commit -m commit-1
$ hg tip
changeset: 2:8eeac6695c1c
tag: tip
user: foobar <foo@bar.com>
date: Thu Jan 01 00:00:00 1970 +0000
summary: commit-1
$ echo 1 > asdf
$ hg commit -u "foo@bar.com" -m commit-1
$ hg tip
changeset: 3:957606a725e4
tag: tip
user: foo@bar.com
date: Thu Jan 01 00:00:00 1970 +0000
summary: commit-1
$ echo 123 > asdf
$ echo "[ui]" > .hg/hgrc
$ echo "username = " >> .hg/hgrc
$ hg commit -m commit-1
abort: no username supplied
(use 'hg config --edit' to set your username)
[255]
# test alternate config var
$ echo 1234 > asdf
$ echo "[ui]" > .hg/hgrc
$ echo "user = Foo Bar II <foo2@bar.com>" >> .hg/hgrc
$ hg commit -m commit-1
$ hg tip
changeset: 4:6f24bfb4c617
tag: tip
user: Foo Bar II <foo2@bar.com>
date: Thu Jan 01 00:00:00 1970 +0000
summary: commit-1
# test prompt username
$ cat > .hg/hgrc <<EOF
> [ui]
> askusername = True
> EOF
$ echo 12345 > asdf
$ hg commit --config ui.interactive=False -m ask
enter a commit username:
no username found, using '[^']*' instead (re)
$ hg rollback -q
$ hg commit --config ui.interactive=True -m ask <<EOF
> Asked User <ask@example.com>
> EOF
enter a commit username: Asked User <ask@example.com>
$ hg tip
changeset: 5:84c91d963b70
tag: tip
user: Asked User <ask@example.com>
date: Thu Jan 01 00:00:00 1970 +0000
summary: ask
# test no .hg/hgrc (uses generated non-interactive username)
$ echo space > asdf
$ rm .hg/hgrc
$ hg commit -m commit-1 2>&1
no username found, using '[^']*' instead (re)
$ echo space2 > asdf
$ hg commit -u ' ' -m commit-1
transaction abort!
rollback completed
abort: empty username!
[255]
# don't add tests here, previous test is unstable
$ cd ..