1
0
mirror of https://github.com/golang/go synced 2024-11-18 06:54:49 -07:00
The Go programming language
Go to file
Daniel Martí 54697702e4 encoding/json: avoid work when unquoting strings, take 2
This is a re-submission of CL 151157, since it was reverted in CL 190909
due to an introduced crash found by a fuzzer. The revert CL included
regression tests, while this CL includes a fixed version of the original
change.

In particular, what we forgot in the original optimization was that we
still need the length and trailing quote checks at the beginning of
unquoteBytes. Without those, we could end up in a crash later on.

We can work out how many bytes can be unquoted trivially in
rescanLiteral, which already iterates over a string's bytes.

Removing the extra loop in unquoteBytes simplifies the function and
speeds it up, especially when decoding simple strings, which are common.

While at it, we can remove the check that s[0]=='"', since all call
sites already meet that condition.

name           old time/op    new time/op    delta
CodeDecoder-8    10.6ms ± 2%    10.5ms ± 1%  -1.01%  (p=0.004 n=20+10)

name           old speed      new speed      delta
CodeDecoder-8   183MB/s ± 2%   185MB/s ± 1%  +1.02%  (p=0.003 n=20+10)

Updates #28923.

Change-Id: I8c6b13302bcd86a364bc998d72451332c0809cde
Reviewed-on: https://go-review.googlesource.com/c/go/+/190659
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Peter Weinberger <pjw@google.com>
2019-10-31 12:02:57 +00:00
.github
api api/go1.13: add debug/elf.Symbol fields added in CL 184099 2019-08-08 18:44:16 +00:00
doc doc/go1.14: document that Go 1.14 is likely last to support darwin/arm 2019-10-28 16:56:52 +00:00
lib/time
misc misc: delete benchcmp forwarding script 2019-10-23 21:41:15 +00:00
src encoding/json: avoid work when unquoting strings, take 2 2019-10-31 12:02:57 +00:00
test cmd/compile/internal/gc: reword "declared and not used" error message 2019-10-28 23:34:13 +00:00
.gitattributes
.gitignore
AUTHORS A+C: change email address for Akhil Indurti 2019-09-09 15:30:38 +00:00
CONTRIBUTING.md
CONTRIBUTORS C: update email address for utkarsh-extc 2019-10-03 12:39:06 +00:00
favicon.ico
LICENSE
PATENTS
README.md
robots.txt
SECURITY.md SECURITY.md: update go versions 2019-09-26 15:34:57 +00:00

The Go Programming Language

Go is an open source programming language that makes it easy to build simple, reliable, and efficient software.

Gopher image Gopher image by Renee French, licensed under Creative Commons 3.0 Attributions license.

Our canonical Git repository is located at https://go.googlesource.com/go. There is a mirror of the repository at https://github.com/golang/go.

Unless otherwise noted, the Go source files are distributed under the BSD-style license found in the LICENSE file.

Download and Install

Binary Distributions

Official binary distributions are available at https://golang.org/dl/.

After downloading a binary release, visit https://golang.org/doc/install or load doc/install.html in your web browser for installation instructions.

Install From Source

If a binary distribution is not available for your combination of operating system and architecture, visit https://golang.org/doc/install/source or load doc/install-source.html in your web browser for source installation instructions.

Contributing

Go is the work of thousands of contributors. We appreciate your help!

To contribute, please read the contribution guidelines: https://golang.org/doc/contribute.html

Note that the Go project uses the issue tracker for bug reports and proposals only. See https://golang.org/wiki/Questions for a list of places to ask questions about the Go language.