delta/go-git.git/src/strconv, branch dev.cmdgo

strconv: reject surrogate halves in Unquote

2021-08-21T18:23:58+00:00

Unquote implements unescaping a "single-quoted, doubled-quoted, or
backquoted Go string literal". Therefore, it should reject anything
that the Go specification explicitly forbids.

The section on "Rune literals" explicitly rejects rune values
"above 0x10FFFF and surrogate halves". We properly checked for
the previous condition, but were failing to check for the latter.

In general, "r > utf8.MaxRune" is probably the wrong check,
while !utf8.ValidRune(r) is the more correct check.
We make changes to both UnquoteChar and appendEscapedRune
to use the correct check. The change to appendEscapedRune
is technically a noop since callers of that function already
guarantee that the provided rune is valid.

Fixes #47853

Change-Id: Ib8977e56b91943ec8ada821b8d217b5e9a66f950
Reviewed-on: https://go-review.googlesource.com/c/go/+/343877
Trust: Joe Tsai 
Run-TryBot: Joe Tsai 
TryBot-Result: Go Bot 
Reviewed-by: Rob Pike

all: fix typos

2021-08-17T13:54:10+00:00

Change-Id: I83180c472db8795803c1b9be3a33f35959e4dcc2
Reviewed-on: https://go-review.googlesource.com/c/go/+/336889
Reviewed-by: Rob Pike 
Reviewed-by: Austin Clements

strconv: document parsing of leading +/-

2021-06-09T18:16:27+00:00

Explicitly document the handling of a sign prefix, and the interaction
between the sign and base prefixes.

Fixes #46641.

Change-Id: I3cd6773e3f074fe671a944a05a79d2408137fcd4
Reviewed-on: https://go-review.googlesource.com/c/go/+/325875
Trust: Damien Neil 
Run-TryBot: Damien Neil 
TryBot-Result: Go Bot 
Reviewed-by: Rob Pike

strconv: ParseFloat: always return ErrSyntax for bad syntax

2021-06-07T21:12:46+00:00

Previously we would sometimes return ErrRange if the parseable part of
the floating point number was out of range.

Fixes #46628

Change-Id: I15bbbb1e2a56fa27c19fe25ab5554d988cbfd9d2
Reviewed-on: https://go-review.googlesource.com/c/go/+/325750
Trust: Ian Lance Taylor 
Trust: Robert Griesemer 
Run-TryBot: Ian Lance Taylor 
TryBot-Result: Go Bot 
Reviewed-by: Robert Griesemer

strconv: fix a typo

2021-05-04T03:22:47+00:00

Change-Id: I17911dc95fb2126b41dc95f8839c4b3fa8f35d12
GitHub-Last-Rev: 88e120329301bd73db39e1081737a83f49a5672b
GitHub-Pull-Request: golang/go#45933
Reviewed-on: https://go-review.googlesource.com/c/go/+/316689
Reviewed-by: Robert Griesemer 
Reviewed-by: Ian Lance Taylor

strconv: add QuotedPrefix

2021-05-04T00:56:00+00:00

QuotedPrefix is similar to Unquote, but returns the quoted string verbatim
and ignores any data after the quoted string.

Fixes #45033

Change-Id: I9f69fe9e3e45cbe9e63581cf1b457facb625045d
Reviewed-on: https://go-review.googlesource.com/c/go/+/314775
Trust: Joe Tsai 
Reviewed-by: Ian Lance Taylor 
Run-TryBot: Ian Lance Taylor 
TryBot-Result: Go Bot

strconv: remove unused extfloat (Grisu3) ftoa code

2021-04-27T17:03:53+00:00

Change-Id: Ie8995362f9e8072b173d08820330d2d1e512aa71
Reviewed-on: https://go-review.googlesource.com/c/go/+/314029
Trust: Robert Griesemer 
Run-TryBot: Robert Griesemer 
TryBot-Result: Go Bot 
Reviewed-by: Robert Griesemer 
Reviewed-by: Emmanuel Odeke

strconv: Implement Ryū algorithm for ftoa shortest mode

2021-04-15T09:18:03+00:00

This patch implements the algorithm from Ulf Adams,
"Ryū: Fast Float-to-String Conversion" (doi:10.1145/3192366.3192369)
for formatting floating-point numbers with a fixed number of decimal
digits.

It is not a direct translation of the reference C implementation
but still follows the original paper. In particular, it uses full
128-bit powers of 10, which allows for more precision in the other
modes (fixed ftoa, atof).

name                              old time/op  new time/op   delta
AppendFloat/Decimal-4             49.6ns ± 3%   59.3ns ± 0%  +19.59%  (p=0.008 n=5+5)
AppendFloat/Float-4                122ns ± 1%     91ns ± 1%  -25.92%  (p=0.008 n=5+5)
AppendFloat/Exp-4                 89.3ns ± 1%  100.0ns ± 1%  +11.98%  (p=0.008 n=5+5)
AppendFloat/NegExp-4              88.3ns ± 2%   97.1ns ± 1%   +9.87%  (p=0.008 n=5+5)
AppendFloat/LongExp-4              143ns ± 2%    103ns ± 0%  -28.17%  (p=0.016 n=5+4)
AppendFloat/Big-4                  144ns ± 1%    110ns ± 1%  -23.26%  (p=0.008 n=5+5)
AppendFloat/BinaryExp-4           46.2ns ± 2%   46.0ns ± 1%     ~     (p=0.603 n=5+5)
AppendFloat/32Integer-4           49.1ns ± 1%   58.7ns ± 1%  +19.57%  (p=0.008 n=5+5)
AppendFloat/32ExactFraction-4     95.6ns ± 1%   88.6ns ± 1%   -7.30%  (p=0.008 n=5+5)
AppendFloat/32Point-4              122ns ± 1%     87ns ± 1%  -28.63%  (p=0.008 n=5+5)
AppendFloat/32Exp-4               88.6ns ± 2%   95.0ns ± 1%   +7.29%  (p=0.008 n=5+5)
AppendFloat/32NegExp-4            87.2ns ± 1%   91.3ns ± 1%   +4.63%  (p=0.008 n=5+5)
AppendFloat/32Shortest-4           107ns ± 1%     82ns ± 0%  -24.08%  (p=0.008 n=5+5)
AppendFloat/Slowpath64-4          1.00µs ± 1%   0.10µs ± 0%  -89.92%  (p=0.016 n=5+4)
AppendFloat/SlowpathDenormal64-4  34.1µs ± 3%    0.1µs ± 1%  -99.72%  (p=0.008 n=5+5)

Fixes #15672

Change-Id: Ib90dfa245f62490a6666671896013cf3f9a1fb22
Reviewed-on: https://go-review.googlesource.com/c/go/+/170080
Trust: Emmanuel Odeke 
Trust: Nigel Tao 
Run-TryBot: Emmanuel Odeke 
TryBot-Result: Go Bot 
Reviewed-by: Nigel Tao

strconv: implement Ryū-like algorithm for fixed precision ftoa

2021-04-15T08:44:21+00:00

This patch implements a simplified version of Ulf Adams,
"Ryū: Fast Float-to-String Conversion" (doi:10.1145/3192366.3192369)
for formatting floating-point numbers with a fixed number of decimal
digits.

It uses the same principles but does not need to handle
the complex task of finding a shortest representation.
This allows to handle a few more cases than Grisu3, notably
formatting with up to 18 significant digits.

name                         old time/op  new time/op  delta
AppendFloat/32Fixed8Hard-4   72.0ns ± 2%  56.0ns ± 2%  -22.28%  (p=0.000 n=10+10)
AppendFloat/32Fixed9Hard-4   74.8ns ± 0%  64.2ns ± 2%  -14.16%  (p=0.000 n=8+10)
AppendFloat/64Fixed1-4       60.4ns ± 1%  54.2ns ± 1%  -10.31%  (p=0.000 n=10+9)
AppendFloat/64Fixed2-4       66.3ns ± 1%  53.3ns ± 1%  -19.54%  (p=0.000 n=10+9)
AppendFloat/64Fixed3-4       61.0ns ± 1%  55.0ns ± 2%   -9.80%  (p=0.000 n=9+10)
AppendFloat/64Fixed4-4       66.9ns ± 0%  52.0ns ± 2%  -22.20%  (p=0.000 n=8+10)
AppendFloat/64Fixed12-4      95.5ns ± 1%  76.2ns ± 3%  -20.19%  (p=0.000 n=10+9)
AppendFloat/64Fixed16-4      1.62µs ± 0%  0.07µs ± 2%  -95.69%  (p=0.000 n=10+10)
AppendFloat/64Fixed12Hard-4  1.27µs ± 1%  0.07µs ± 1%  -94.83%  (p=0.000 n=9+9)
AppendFloat/64Fixed17Hard-4  3.68µs ± 1%  0.08µs ± 2%  -97.86%  (p=0.000 n=10+9)
AppendFloat/64Fixed18Hard-4  3.67µs ± 0%  3.72µs ± 1%   +1.44%  (p=0.000 n=9+10)

Updates #15672

Change-Id: I160963e141dd48287ad8cf57bcc3c686277788e8
Reviewed-on: https://go-review.googlesource.com/c/go/+/170079
Reviewed-by: Emmanuel Odeke 
Trust: Emmanuel Odeke 
Trust: Nigel Tao 
Trust: Robert Griesemer 
Run-TryBot: Emmanuel Odeke 
TryBot-Result: Go Bot

all: faster midpoint computation in binary search

2021-02-23T01:37:31+00:00

On my machine (3.1 GHz Quad-Core Intel Core i7, macOS 10.15.7 10.15.7), go 1.15.6

benchstat:
name          old time/op  new time/op  delta
SearchInts-8  20.3ns ± 1%  16.6ns ± 6%  -18.37%  (p=0.000 n=9+10)

Change-Id: I346e5955fd6df6ce10254b22267dbc8d5a2b16c0
Reviewed-on: https://go-review.googlesource.com/c/go/+/279439
Reviewed-by: Ben Shi 
Reviewed-by: Robert Griesemer 
Trust: Robert Griesemer