From bc8bb5b27a5abe48fbfc79ae4a1ce4c87ca90bbc Mon Sep 17 00:00:00 2001 From: Ilya Tocar Date: Tue, 12 Sep 2017 15:31:09 -0500 Subject: [PATCH] unicode: speed-up is16/is32 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Avoid division in common case. There are 5438 ranges in unicode/tables.go 4110 of them have stride 1. Stride 1 case got significantly faster. Other stride is a bit slower. Measured by import ( "testing" "unicode" ) func BenchmarkDiv1(b *testing.B) { rtb := &unicode.RangeTable{ R16: []unicode.Range16{ {0xa800, 0xdfff, 1}, // or 3 }, } for i := 0; i < b.N; i++ { unicode.Is(rtb, rune(0xc700)) } } Div1-6 15.6ns ± 1% 9.9ns ± 1% -36.54% (p=0.000 n=10+10) Div3-6 15.5ns ± 1% 16.1ns ± 1% +3.67% (p=0.000 n=10+10) Helps a bit with xml parsing from issue #21823 XMLsax-6 30.9s ± 0% 29.6s ± 0% -4.15% (p=0.000 n=10+9) Change-Id: Ibac1a91d7b9474d0c134b0add83e56caa62daa20 Reviewed-on: https://go-review.googlesource.com/63390 Run-TryBot: Ilya Tocar TryBot-Result: Gobot Gobot Reviewed-by: Ian Lance Taylor --- src/unicode/letter.go | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/src/unicode/letter.go b/src/unicode/letter.go index 90b0b414da..4d9fc67165 100644 --- a/src/unicode/letter.go +++ b/src/unicode/letter.go @@ -97,7 +97,7 @@ func is16(ranges []Range16, r uint16) bool { return false } if r <= range_.Hi { - return (r-range_.Lo)%range_.Stride == 0 + return range_.Stride == 1 || (r-range_.Lo)%range_.Stride == 0 } } return false @@ -110,7 +110,7 @@ func is16(ranges []Range16, r uint16) bool { m := lo + (hi-lo)/2 range_ := &ranges[m] if range_.Lo <= r && r <= range_.Hi { - return (r-range_.Lo)%range_.Stride == 0 + return range_.Stride == 1 || (r-range_.Lo)%range_.Stride == 0 } if r < range_.Lo { hi = m @@ -130,7 +130,7 @@ func is32(ranges []Range32, r uint32) bool { return false } if r <= range_.Hi { - return (r-range_.Lo)%range_.Stride == 0 + return range_.Stride == 1 || (r-range_.Lo)%range_.Stride == 0 } } return false @@ -143,7 +143,7 @@ func is32(ranges []Range32, r uint32) bool { m := lo + (hi-lo)/2 range_ := ranges[m] if range_.Lo <= r && r <= range_.Hi { - return (r-range_.Lo)%range_.Stride == 0 + return range_.Stride == 1 || (r-range_.Lo)%range_.Stride == 0 } if r < range_.Lo { hi = m