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31 Commits

Author SHA1 Message Date
Emmanuel Odeke
7b40b0c3a3 strings, bytes: panic if Repeat overflows or if given a negative count
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 <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-10-01 15:47:35 +00:00
Ilya Tocar
0cff219c12 strings: use AVX2 for Index if available
IndexHard4-4      1.50ms ± 2%  0.71ms ± 0%  -52.36%  (p=0.000 n=20+19)

This also fixes a bug, that caused a string of length 16 to use
two 8-byte comparisons instead of one 16-byte. And adds a test for
cases when partial_match fails.

Change-Id: I1ee8fc4e068bb36c95c45de78f067c822c0d9df0
Reviewed-on: https://go-review.googlesource.com/22551
Run-TryBot: Ilya Tocar <ilya.tocar@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2016-09-07 10:43:13 +00:00
Hiroshi Ioka
8737dac1f2 strings: make IndexRune faster
re-implement IndexRune by Index which is well optimized to get
performance gain.

name                   old time/op  new time/op  delta
IndexRune-4            30.2ns ± 1%  28.3ns ± 1%   -6.22%  (p=0.000 n=20+19)
IndexRuneLongString-4   156ns ± 1%    49ns ± 1%  -68.72%  (p=0.000 n=19+19)
IndexRuneFastPath-4    10.6ns ± 2%  10.0ns ± 1%   -6.30%  (p=0.000 n=18+18)

Change-Id: Ie663b8f7860ca51892dd4be182fca3caa5f8ae61
Reviewed-on: https://go-review.googlesource.com/28546
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-09-07 01:03:10 +00:00
Brad Fitzpatrick
3ddc9ad916 strings: add special cases for Join of 2 and 3 strings
We already had special cases for 0 and 1. Add 2 and 3 for now too.
To be removed if the compiler is improved later (#6714).

This halves the number of allocations and total bytes allocated via
common filepath.Join calls, improving filepath.Walk performance.

Noticed as part of investigating filepath.Walk in #16399.

Change-Id: If7b1bb85606d4720f3ebdf8de7b1e12ad165079d
Reviewed-on: https://go-review.googlesource.com/25005
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
2016-08-16 00:33:15 +00:00
Ilya Tocar
429bbf3312 strings: fix and reenable amd64 Index for 17-31 byte strings
Fixes #15689

Change-Id: I56d0103738cc35cd5bc5e77a0e0341c0dd55530e
Reviewed-on: https://go-review.googlesource.com/23440
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Ilya Tocar <ilya.tocar@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Nigel Tao <nigeltao@golang.org>
2016-05-27 22:57:32 +00:00
Keith Randall
0bc14f57ec strings: fix Contains on amd64
The 17-31 byte code is broken.  Disabled it.

Added a bunch of tests to at least cover the cases
in indexShortStr.  I'll channel Brad and wonder why
this CL ever got in without any tests.

Fixes #15679

Change-Id: I84a7b283a74107db865b9586c955dcf5f2d60161
Reviewed-on: https://go-review.googlesource.com/23106
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-05-15 05:21:03 +00:00
Joe Tsai
acc757f678 all: use SeekStart, SeekCurrent, SeekEnd
CL/19862 (f79b50b8d5) recently introduced the constants
SeekStart, SeekCurrent, and SeekEnd to the io package. We should use these constants
consistently throughout the code base.

Updates #15269

Change-Id: If7fcaca7676e4a51f588528f5ced28220d9639a2
Reviewed-on: https://go-review.googlesource.com/22097
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Joe Tsai <joetsai@digital-static.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-05-06 00:10:41 +00:00
Brad Fitzpatrick
01182425f8 strings, bytes: fix Reader 0 byte read at EOF
0 byte reads at EOF weren't returning EOF.

Change-Id: I19b5fd5a72e83d49566a230ce4067be03f00d14b
Reviewed-on: https://go-review.googlesource.com/22740
Reviewed-by: Bryan Mills <bcmills@google.com>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-05-03 21:01:13 +00:00
Matthew Dempsky
0da4dbe232 all: remove unnecessary type conversions
cmd and runtime were handled separately, and I'm intentionally skipped
syscall. This is the rest of the standard library.

CL generated mechanically with github.com/mdempsky/unconvert.

Change-Id: I9e0eff886974dedc37adb93f602064b83e469122
Reviewed-on: https://go-review.googlesource.com/22104
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-04-15 07:31:45 +00:00
Brad Fitzpatrick
381e5eee39 all: use new io.SeekFoo constants instead of os.SEEK_FOO
Automated change.

Fixes #15269

Change-Id: I8deb2ac0101d3f7c390467ceb0a1561b72edbb2f
Reviewed-on: https://go-review.googlesource.com/21962
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Andrew Gerrand <adg@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-04-13 05:25:23 +00:00
Martin Möhrmann
819e0b29bb strings: improve explode and correct comment
Merges explodetests into splittests which already contain
some of the tests that cover explode.

Adds a test to cover the utf8.RuneError branch in explode.

name      old time/op  new time/op  delta
Split1-2  14.9ms ± 0%  14.2ms ± 0%  -4.06%  (p=0.000 n=47+49)

Change-Id: I00f796bd2edab70e926ea9e65439d820c6a28254
Reviewed-on: https://go-review.googlesource.com/21609
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2016-04-13 04:54:03 +00:00
Joe Tsai
e88f89028a bytes, string: add Reset method to Reader
Currently, there is no easy allocation-free way to turn a
[]byte or string into an io.Reader. Thus, we add a Reset method
to bytes.Reader and strings.Reader to allow the reuse of these
Readers with another []byte or string.

This is consistent with the fact that many standard library io.Readers
already support a Reset method of some type:
	bufio.Reader
	flate.Reader
	gzip.Reader
	zlib.Reader
	debug/dwarf.LineReader
	bytes.Buffer
	crypto/rc4.Cipher

Fixes #15033

Change-Id: I456fd1af77af6ef0b4ac6228b058ac1458ff3d19
Reviewed-on: https://go-review.googlesource.com/21386
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-04-07 18:58:01 +00:00
Brad Fitzpatrick
5fea2ccc77 all: single space after period.
The tree's pretty inconsistent about single space vs double space
after a period in documentation. Make it consistently a single space,
per earlier decisions. This means contributors won't be confused by
misleading precedence.

This CL doesn't use go/doc to parse. It only addresses // comments.
It was generated with:

$ perl -i -npe 's,^(\s*// .+[a-z]\.)  +([A-Z]),$1 $2,' $(git grep -l -E '^\s*//(.+\.)  +([A-Z])')
$ go test go/doc -update

Change-Id: Iccdb99c37c797ef1f804a94b22ba5ee4b500c4f7
Reviewed-on: https://go-review.googlesource.com/20022
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Dave Day <djd@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-03-02 00:13:47 +00:00
Brad Fitzpatrick
519474451a all: make copyright headers consistent with one space after period
This is a subset of https://golang.org/cl/20022 with only the copyright
header lines, so the next CL will be smaller and more reviewable.

Go policy has been single space after periods in comments for some time.

The copyright header template at:

    https://golang.org/doc/contribute.html#copyright

also uses a single space.

Make them all consistent.

Change-Id: Icc26c6b8495c3820da6b171ca96a74701b4a01b0
Reviewed-on: https://go-review.googlesource.com/20111
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-03-01 23:34:33 +00:00
Brad Fitzpatrick
351c15f1ce all: remove public named return values when useless
Named returned values should only be used on public funcs and methods
when it contributes to the documentation.

Named return values should not be used if they're only saving the
programmer a few lines of code inside the body of the function,
especially if that means there's stutter in the documentation or it
was only there so the programmer could use a naked return
statement. (Naked returns should not be used except in very small
functions)

This change is a manual audit & cleanup of public func signatures.

Signatures were not changed if:

* the func was private (wouldn't be in public godoc)
* the documentation referenced it
* the named return value was an interesting name. (i.e. it wasn't
  simply stutter, repeating the name of the type)

There should be no changes in behavior. (At least: none intended)

Change-Id: I3472ef49619678fe786e5e0994bdf2d9de76d109
Reviewed-on: https://go-review.googlesource.com/20024
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Andrew Gerrand <adg@golang.org>
2016-02-29 03:31:19 +00:00
Ilya Tocar
95333aea53 strings: add asm version of Index() for short strings on amd64
Currently we have special case for 1-byte strings,
This extends this to strings shorter than 32 bytes on amd64.
Results (broadwell):

name                 old time/op  new time/op  delta
IndexRune-4          57.4ns ± 0%  57.5ns ± 0%   +0.10%        (p=0.000 n=20+19)
IndexRuneFastPath-4  20.4ns ± 0%  20.4ns ± 0%     ~     (all samples are equal)
Index-4              21.0ns ± 0%  21.8ns ± 0%   +3.81%        (p=0.000 n=20+20)
LastIndex-4          7.07ns ± 1%  6.98ns ± 0%   -1.21%        (p=0.000 n=20+16)
IndexByte-4          18.3ns ± 0%  18.3ns ± 0%     ~     (all samples are equal)
IndexHard1-4         1.46ms ± 0%  0.39ms ± 0%  -73.06%        (p=0.000 n=16+16)
IndexHard2-4         1.46ms ± 0%  0.30ms ± 0%  -79.55%        (p=0.000 n=18+18)
IndexHard3-4         1.46ms ± 0%  0.66ms ± 0%  -54.68%        (p=0.000 n=19+19)
LastIndexHard1-4     1.46ms ± 0%  1.46ms ± 0%   -0.01%        (p=0.036 n=18+20)
LastIndexHard2-4     1.46ms ± 0%  1.46ms ± 0%     ~           (p=0.588 n=19+19)
LastIndexHard3-4     1.46ms ± 0%  1.46ms ± 0%     ~           (p=0.283 n=17+20)
IndexTorture-4       11.1µs ± 0%  11.1µs ± 0%   +0.01%        (p=0.000 n=18+17)

Change-Id: I892781549f558f698be4e41f9f568e3d0611efb5
Reviewed-on: https://go-review.googlesource.com/16430
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Ilya Tocar <ilya.tocar@intel.com>
2015-11-03 16:04:28 +00:00
Gaurish Sharma
c7e2eaff95 strings: Add examples for HasPrefix and HasSuffix
These methods didn't had any examples, so added them. Examples makes things more clear
diff --git a/src/strings/example_test.go b/src/strings/example_test.go
index 7243e16..b7763bb 100644
--- a/src/strings/example_test.go
+++ b/src/strings/example_test.go
@@ -223,3 +223,19 @@ func ExampleTrimPrefix() {
 	fmt.Print("Hello" + s)
 	// Output: Hello, world!
 }
+
+func ExampleHasPrefix() {
+	fmt.Println(strings.HasPrefix("hello", "hell"))
+	fmt.Println(strings.HasPrefix("hello", "heaven"))
+	// Output:
+	// true
+	// false
+}
+
+func ExampleHasSuffix() {
+	fmt.Println(strings.HasSuffix("hello", "llo"))
+	fmt.Println(strings.HasSuffix("hello", "hell"))
+	// Output:
+	// true
+	// false
+}

Change-Id: I5d451c669bd05e19a2afc33ed2ec59b280c2c2d9
Reviewed-on: https://go-review.googlesource.com/12065
Reviewed-by: Russ Cox <rsc@golang.org>
2015-10-23 01:57:15 +00:00
Brad Fitzpatrick
783297ad6a all: link to https for golang subdomains too
The previous commit (git 2ae77376) just did golang.org.  This one
includes golang.org subdomains like blog, play, and build.

Change-Id: I4469f7b307ae2a12ea89323422044e604c5133ae
Reviewed-on: https://go-review.googlesource.com/12071
Reviewed-by: Rob Pike <r@golang.org>
2015-07-12 04:42:40 +00:00
Rob Pike
cb20146097 strings: mention UTF-8 in the package comment.
Also add a reference to the strings blog post.

Fixes #11045.

Change-Id: Ic0a8908cbd7b51a36d104849fa0e8abfd54de2b9
Reviewed-on: https://go-review.googlesource.com/10662
Reviewed-by: Andrew Gerrand <adg@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-06-03 19:28:41 +00:00
Dmitry Vyukov
cfb8b18e75 strings: use LastIndexByte in LastIndex
Change-Id: I1add1b92f5c2688a99133d90bf9789d770fd9f05
Reviewed-on: https://go-review.googlesource.com/9503
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2015-04-30 08:33:29 +00:00
Dmitry Vyukov
0fb5475bdf bytes, strings: add LastIndexByte
Currently the packages have the following index functions:

func Index(s, sep []byte) int
func IndexAny(s []byte, chars string) int
func IndexByte(s []byte, c byte) int
func IndexFunc(s []byte, f func(r rune) bool) int
func IndexRune(s []byte, r rune) int

func LastIndex(s, sep []byte) int
func LastIndexAny(s []byte, chars string) int
func LastIndexFunc(s []byte, f func(r rune) bool) int

Searching for the last occurrence of a byte is quite common
for string parsing algorithms (e.g. find the last paren on a line).
Also addition of LastIndexByte makes the set more orthogonal.

Change-Id: Ida168849acacf8e78dd70c1354bef9eac5effafe
Reviewed-on: https://go-review.googlesource.com/9500
Reviewed-by: Rob Pike <r@golang.org>
2015-04-30 07:13:18 +00:00
Brad Fitzpatrick
c264c87335 bytes, strings: add Reader.Size methods
As noted on recently on golang-nuts, there's currently no way to know
the total size of a strings.Reader or bytes.Reader when using ReadAt
on them. Most callers resort to wrapping it in an io.SectionReader to
retain that information.

The SizeReaderAt abstraction (an io.ReaderAt with a Size() int64
method) has proven useful as a way of expressing a concurrency-safe
read-only number of bytes.

As one example, see http://talks.golang.org/2013/oscon-dl.slide#49 and
the rest of that presentation for its use in dl.google.com.

SizeReaderAt is also used in the open source google-api-go-client, and
within Google's internal codebase, where it exists in a public package
created in 2013 with the package comment: "These may migrate to the
standard library after we have enough experience with their feel."

I'm still as happy with the SizeReaderAt abstraction and its
composabilty as I was in 2013, so I'd like to make these two Readers
also be SizeReaderAts.

Fixes #9667

Change-Id: Ie6f145ada419dd116280472d8c029f046d5edf70
Reviewed-on: https://go-review.googlesource.com/3199
Reviewed-by: Andrew Gerrand <adg@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
2015-04-06 08:53:47 +00:00
John Potocny
6262192cd0 strings: Add benchmark test for trim function
The strings.Trim function and variants allocate memory on the heap when creating a function to pass into TrimFunc.
Add a benchmark to document the behavior; an issue will be submitted to address this behavior in the compiler if possible.

Change-Id: I8b66721f077951f7e7b8cf3cf346fac27a9b68c0
Reviewed-on: https://go-review.googlesource.com/8200
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-03-31 00:40:55 +00:00
areski
3f12d27133 bytes, os/exec, strings: fix a few BUG comments
Regular expression noteMarker requires the definition of a (who) section
when reading note from a sequence of comments.

Change-Id: I9635de9b86f00d20ec108097fee4d4a8f76237b2
Reviewed-on: https://go-review.googlesource.com/1952
Reviewed-by: Russ Cox <rsc@golang.org>
2015-03-20 18:34:39 +00:00
Josh Bleecher Snyder
2adc4e8927 all: use "reports whether" in place of "returns true if(f)"
Comment changes only.

Change-Id: I56848814564c4aa0988b451df18bebdfc88d6d94
Reviewed-on: https://go-review.googlesource.com/7721
Reviewed-by: Rob Pike <r@golang.org>
2015-03-18 15:14:06 +00:00
Robert Griesemer
19c1b163e8 bytes, strings: improve documentation for Count functions
Fixes #9659.

Change-Id: If364d5984a0c9a48858ae524b1560f633e621826
Reviewed-on: https://go-review.googlesource.com/3181
Reviewed-by: Rob Pike <r@golang.org>
2015-01-22 18:28:35 +00:00
Russ Cox
fd4dc91a96 strings: remove overengineered Compare implementation
The function is here ONLY for symmetry with package bytes.
This function should be used ONLY if it makes code clearer.
It is not here for performance. Remove any performance benefit.

If performance becomes an issue, the compiler should be fixed to
recognize the three-way compare (for all comparable types)
rather than encourage people to micro-optimize by using this function.

Change-Id: I71f4130bce853f7aef724c6044d15def7987b457
Reviewed-on: https://go-review.googlesource.com/3012
Reviewed-by: Rob Pike <r@golang.org>
2015-01-19 02:19:17 +00:00
Alan Donovan
90ce1936e3 strings: add Compare(x, y string) int, for symmetry with bytes.Compare
The implementation is the same assembly (or Go) routine.

Change-Id: Ib937c461c24ad2d5be9b692b4eed40d9eb031412
Reviewed-on: https://go-review.googlesource.com/2828
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2015-01-15 17:17:05 +00:00
Brad Fitzpatrick
4731c382f6 strings: use fast path for IndexRune
Noticed while reviewing https://golang.org/cl/147690043/

I'd never seen anybody use IndexRune before, and
unsurprisingly it doesn't use the other fast paths in the
strings/bytes packages. IndexByte uses assembly.

Also, less code this way.

LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/147700043
2014-10-06 15:10:51 -07:00
Russ Cox
e9ec8e7a26 bytes, strings: document that FieldsFunc f must not be stateful
Fixes #8738.

LGTM=adg
R=golang-codereviews, adg
CC=golang-codereviews
https://golang.org/cl/143260045
2014-09-18 19:40:31 -04:00
Russ Cox
c007ce824d build: move package sources from src/pkg to src
Preparation was in CL 134570043.
This CL contains only the effect of 'hg mv src/pkg/* src'.
For more about the move, see golang.org/s/go14nopkg.
2014-09-08 00:08:51 -04:00