delta/go-git.git/src/bytes, branch dev.inline

all: make copyright headers consistent with one space after period

2016-11-04T20:46:25+00:00

Continuation of CL 20111.

Change-Id: Ie2f62237e6ec316989c021de9b267cc9d6ee6676
Reviewed-on: https://go-review.googlesource.com/32830
Reviewed-by: Brad Fitzpatrick

bytes, strings: update s390x code to match amd64 changes

2016-11-02T15:56:24+00:00

Updates the s390x-specific files in these packages with the changes
to the amd64-specific files made during the review of CL 31690. I'd
like to keep these files in sync unless there is a reason to
diverge.

Change-Id: Id83e5ce11a45f877bdcc991d02b14416d1a2d8d2
Reviewed-on: https://go-review.googlesource.com/32574
Reviewed-by: Brad Fitzpatrick

bytes,strings: use IndexByte more often in Index on AMD64

2016-11-01T18:30:52+00:00

IndexByte+compare is faster than indexShortStr in good case, when
first byte is rare, but is more costly in bad cases.
Start with IndexByte and switch to indexShortStr if we encounter
false positives more often than once per 8 bytes.

Benchmark changes for package bytes:

IndexRune/4K-8                    416ns ± 0%       86ns ± 0%    -79.24%        (p=0.000 n=10+10)
IndexRune/4M-8                    413µs ± 0%      100µs ± 1%    -75.88%        (p=0.000 n=10+10)
IndexRune/64M-8                  6.73ms ± 0%     2.86ms ± 1%    -57.49%        (p=0.000 n=10+10)
Index/10-8                       8.45ns ± 0%     8.96ns ± 0%     +6.04%         (p=0.000 n=9+10)
Index/32-8                       9.64ns ± 0%     9.51ns ± 0%     -1.30%          (p=0.000 n=8+9)
Index/4K-8                       2.11µs ± 0%     2.12µs ± 0%     +0.26%        (p=0.000 n=10+10)
Index/4M-8                       3.60ms ± 5%     3.59ms ± 7%       ~            (p=0.497 n=9+10)
Index/64M-8                      57.1ms ± 3%     58.7ms ± 5%       ~            (p=0.113 n=9+10)
IndexEasy/10-8                   7.10ns ± 1%     7.71ns ± 1%     +8.60%        (p=0.000 n=10+10)
IndexEasy/32-8                   9.29ns ± 1%     9.22ns ± 0%     -0.75%         (p=0.000 n=9+10)
IndexEasy/4K-8                   1.06µs ± 0%     0.08µs ± 0%    -92.18%        (p=0.000 n=10+10)
IndexEasy/4M-8                   1.07ms ± 0%     0.10ms ± 1%    -90.74%         (p=0.000 n=9+10)
IndexEasy/64M-8                  17.3ms ± 0%      2.8ms ± 1%    -83.76%         (p=0.000 n=10+9)

IndexRune/4K-8                 9.84GB/s ± 0%  47.42GB/s ± 0%   +381.85%         (p=0.000 n=8+10)
IndexRune/4M-8                 10.1GB/s ± 0%   42.1GB/s ± 1%   +314.56%        (p=0.000 n=10+10)
IndexRune/64M-8                10.0GB/s ± 0%   23.4GB/s ± 1%   +135.25%        (p=0.000 n=10+10)
Index/10-8                     1.18GB/s ± 0%   1.12GB/s ± 0%     -5.67%         (p=0.000 n=10+9)
Index/32-8                     3.32GB/s ± 0%   3.36GB/s ± 0%     +1.27%         (p=0.000 n=10+9)
Index/4K-8                     1.94GB/s ± 0%   1.93GB/s ± 0%     -0.25%         (p=0.000 n=10+9)
Index/4M-8                     1.17GB/s ± 5%   1.17GB/s ± 7%       ~            (p=0.497 n=9+10)
Index/64M-8                    1.17GB/s ± 3%   1.15GB/s ± 6%       ~            (p=0.113 n=9+10)
IndexEasy/10-8                 1.41GB/s ± 1%   1.30GB/s ± 1%     -7.90%        (p=0.000 n=10+10)
IndexEasy/32-8                 3.45GB/s ± 1%   3.47GB/s ± 0%     +0.73%         (p=0.000 n=9+10)
IndexEasy/4K-8                 3.84GB/s ± 0%  49.16GB/s ± 0%  +1178.78%         (p=0.000 n=9+10)
IndexEasy/4M-8                 3.91GB/s ± 0%  42.19GB/s ± 1%   +980.37%         (p=0.000 n=9+10)
IndexEasy/64M-8                3.88GB/s ± 0%  23.91GB/s ± 1%   +515.76%         (p=0.000 n=10+9)

No significant changes in strings.

In regexp I see:

Match/Easy0/32-8                 536MB/s ± 1%   540MB/s ± 1%    +0.75%         (p=0.001 n=9+10)
Match/Easy0/1K-8                1.62GB/s ± 0%  4.42GB/s ± 1%  +172.48%        (p=0.000 n=10+10)
Match/Easy0/32K-8               1.87GB/s ± 0%  9.07GB/s ± 1%  +384.24%         (p=0.000 n=7+10)
Match/Easy0/1M-8                1.90GB/s ± 0%  4.83GB/s ± 0%  +154.56%         (p=0.000 n=8+10)
Match/Easy0/32M-8               1.90GB/s ± 0%  4.53GB/s ± 0%  +138.62%         (p=0.000 n=7+10)

Compared to in 1.7:

Match/Easy0/32-8                  59.5ns ± 0%    59.2ns ± 1%   -0.45%         (p=0.008 n=9+10)
Match/Easy0/1K-8                   226ns ± 1%     231ns ± 1%   +2.30%        (p=0.000 n=10+10)
Match/Easy0/32K-8                 3.73µs ± 2%    3.61µs ± 1%   -3.12%        (p=0.000 n=10+10)
Match/Easy0/1M-8                   206µs ± 1%     217µs ± 0%   +5.34%        (p=0.000 n=10+10)
Match/Easy0/32M-8                 7.03ms ± 1%    7.40ms ± 0%   +5.23%        (p=0.000 n=10+10)

Fixes #17456

Change-Id: I38b2fabcaed7119cc4bf37007ba7bfe7504c8f9f
Reviewed-on: https://go-review.googlesource.com/31690
Run-TryBot: Ilya Tocar 
Reviewed-by: Keith Randall

bytes, strings: optimize multi-byte index operations on s390x

2016-11-01T13:17:57+00:00

Use vector instructions to speed up indexing operations for short
strings (64 bytes or less).

bytes_s390x.go and strings_s390x.go are based on their amd64
equivalents in CL 31690.

bytes package:

name                   old time/op    new time/op    delta
Index/10                 40.3ns ± 7%    11.3ns ± 4%    -72.06%  (p=0.000 n=10+10)
Index/32                  196ns ± 1%      27ns ± 2%    -86.25%  (p=0.000 n=10+10)
Index/4K                 28.9µs ± 1%     1.5µs ± 2%    -94.94%    (p=0.000 n=9+9)
Index/4M                 30.1ms ± 2%     1.5ms ± 3%    -94.94%  (p=0.000 n=10+10)
Index/64M                 549ms ±13%      28ms ± 3%    -94.87%   (p=0.000 n=10+9)
IndexEasy/10             18.8ns ±11%    11.5ns ± 2%    -38.81%  (p=0.000 n=10+10)
IndexEasy/32             23.6ns ± 6%    28.1ns ± 3%    +19.29%  (p=0.000 n=10+10)
IndexEasy/4K              251ns ± 5%     223ns ± 8%    -11.04%  (p=0.000 n=10+10)
IndexEasy/4M              318µs ± 9%     266µs ± 8%    -16.42%  (p=0.000 n=10+10)
IndexEasy/64M            14.7ms ±16%    13.2ms ±11%    -10.22%  (p=0.001 n=10+10)

strings package:

name                   old time/op  new time/op  delta
IndexRune              88.1ns ±16%  28.9ns ± 4%  -67.20%  (p=0.000 n=10+10)
IndexRuneLongString     456ns ± 7%    34ns ± 3%  -92.50%  (p=0.000 n=10+10)
IndexRuneFastPath      12.9ns ±14%  11.1ns ± 6%  -13.84%  (p=0.000 n=10+10)
Index                  13.0ns ± 7%  11.3ns ± 4%  -13.31%  (p=0.000 n=10+10)
IndexHard1             3.38ms ± 9%  0.07ms ± 1%  -97.79%  (p=0.000 n=10+10)
IndexHard2             3.58ms ± 7%  0.37ms ± 2%  -89.78%  (p=0.000 n=10+10)
IndexHard3             3.47ms ± 7%  0.75ms ± 1%  -78.52%  (p=0.000 n=10+10)
IndexHard4             3.56ms ± 6%  1.34ms ± 0%  -62.39%    (p=0.000 n=9+9)

Change-Id: If36c2afb8c02e80fcaa1cf5ec2abb0a2be08c7d1
Reviewed-on: https://go-review.googlesource.com/32447
Run-TryBot: Michael Munday 
Reviewed-by: Brad Fitzpatrick

bytes, strings: optimize for ASCII sets

2016-10-28T17:37:04+00:00

In a large codebase within Google, there are thousands of uses of:
	ContainsAny|IndexAny|LastIndexAny|Trim|TrimLeft|TrimRight

An analysis of their usage shows that over 97% of them only use character
sets consisting of only ASCII symbols.

Uses of ContainsAny|IndexAny|LastIndexAny:
	 6% are 1   character  (e.g., "\n" or " ")
	58% are 2-4 characters (e.g., "<>" or "\r\n\t ")
	24% are 5-9 characters (e.g., "()[]*^$")
	10% are 10+ characters (e.g., "+-=&|>
TryBot-Result: Gobot Gobot 
Reviewed-by: Brad Fitzpatrick 
Reviewed-by: Martin Möhrmann

bytes, strings: fix regression in IndexRune

2016-10-26T23:02:27+00:00

In all previous versions of Go, the behavior of IndexRune(s, r)
where r was utf.RuneError was that it would effectively return the
index of any invalid UTF-8 byte sequence (include RuneError).
Optimizations made in http://golang.org/cl/28537 and
http://golang.org/cl/28546 altered this undocumented behavior such
that RuneError would only match on the RuneError rune itself.

Although, the new behavior is arguably reasonable, it did break code
that depended on the previous behavior. Thus, we add special checks
to ensure that we preserve the old behavior.

There is a slight performance hit for correctness:
	benchmark                   old ns/op     new ns/op     delta
	BenchmarkIndexRune/10-4     19.3          21.6          +11.92%
	BenchmarkIndexRune/32-4     33.6          35.2          +4.76%
This only occurs on small strings. The performance hit for larger strings
is neglible and not shown.

Fixes #17611

Change-Id: I1d863a741213d46c40b2e1724c41245df52502a5
Reviewed-on: https://go-review.googlesource.com/32123
Run-TryBot: Joe Tsai 
TryBot-Result: Gobot Gobot 
Reviewed-by: Brad Fitzpatrick

bytes, strings: fix snake-case in variable name

2016-10-26T21:51:48+00:00

Change-Id: I40896fffbffefa359d08abda346933aa996f628d
Reviewed-on: https://go-review.googlesource.com/32124
Reviewed-by: Brad Fitzpatrick 
Run-TryBot: Brad Fitzpatrick 
TryBot-Result: Gobot Gobot

bytes: encode size of rune read by ReadRune into lastRead to speed up UnreadRune

2016-10-17T06:00:35+00:00

In ReadRune store the size of the rune that was read into lastRead
to avoid the need to call DecodeRuneLast in UnreadRune.

fmt:
name        old time/op  new time/op  delta
ScanInts-4   481µs ± 4%   458µs ± 3%  -4.64%  (p=0.000 n=20+20)

Change-Id: I500848e663a975f426402a4b3d27a541e5cac06c
Reviewed-on: https://go-review.googlesource.com/28817
Reviewed-by: Russ Cox 
Run-TryBot: Russ Cox 
Run-TryBot: Martin Möhrmann 
TryBot-Result: Gobot Gobot

strings, bytes: panic if Repeat overflows or if given a negative count

2016-10-01T15:47:35+00:00

Panic if Repeat is given a negative count or
if the value of (len(*) * count) is detected
to overflow.
We panic because we cannot change the
signature of Repeat to return an error.

Fixes #16237

Change-Id: I9f5ba031a5b8533db0582d7a672ffb715143f3fb
Reviewed-on: https://go-review.googlesource.com/29954
Run-TryBot: Brad Fitzpatrick 
TryBot-Result: Gobot Gobot 
Reviewed-by: Brad Fitzpatrick

bytes: cut 10 seconds off the race builder's benchmark test

2016-09-14T18:22:16+00:00

Don't benchmark so many sizes during the race builder's benchmark run.

This package doesn't even use goroutines.

Cuts off 10 seconds.

Updates #17104

Change-Id: Ibb2c7272c18b9014a775949c656a5b930f197cd4
Reviewed-on: https://go-review.googlesource.com/29158
Reviewed-by: David Crawshaw