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https://github.com/golang/go
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bytes: speed up Fields and FieldsFunc
Applies the optimizations from golang.org/cl/42810 and golang.org/cl/37959 done to the strings package to the bytes package. name old time/op new time/op delta Fields/ASCII/16 417ns ± 4% 118ns ± 3% -71.65% (p=0.000 n=10+10) Fields/ASCII/256 5.95µs ± 3% 0.88µs ± 0% -85.23% (p=0.000 n=10+7) Fields/ASCII/4096 92.3µs ± 1% 12.8µs ± 2% -86.13% (p=0.000 n=10+10) Fields/ASCII/65536 1.49ms ± 1% 0.25ms ± 1% -83.14% (p=0.000 n=10+10) Fields/ASCII/1048576 25.0ms ± 1% 6.5ms ± 2% -74.04% (p=0.000 n=10+10) Fields/Mixed/16 406ns ± 1% 222ns ± 1% -45.24% (p=0.000 n=10+9) Fields/Mixed/256 5.78µs ± 1% 2.27µs ± 1% -60.73% (p=0.000 n=9+10) Fields/Mixed/4096 97.9µs ± 1% 40.5µs ± 3% -58.66% (p=0.000 n=10+10) Fields/Mixed/65536 1.58ms ± 1% 0.69ms ± 1% -56.58% (p=0.000 n=10+10) Fields/Mixed/1048576 26.6ms ± 1% 12.6ms ± 2% -52.44% (p=0.000 n=9+10) FieldsFunc/ASCII/16 395ns ± 1% 188ns ± 1% -52.34% (p=0.000 n=10+10) FieldsFunc/ASCII/256 5.90µs ± 1% 2.00µs ± 1% -66.06% (p=0.000 n=10+10) FieldsFunc/ASCII/4096 92.5µs ± 1% 33.0µs ± 1% -64.34% (p=0.000 n=10+9) FieldsFunc/ASCII/65536 1.48ms ± 1% 0.54ms ± 1% -63.38% (p=0.000 n=10+9) FieldsFunc/ASCII/1048576 25.1ms ± 1% 10.5ms ± 3% -58.24% (p=0.000 n=10+10) FieldsFunc/Mixed/16 401ns ± 1% 205ns ± 2% -48.87% (p=0.000 n=10+10) FieldsFunc/Mixed/256 5.70µs ± 1% 1.98µs ± 1% -65.28% (p=0.000 n=10+10) FieldsFunc/Mixed/4096 97.5µs ± 1% 35.4µs ± 1% -63.65% (p=0.000 n=10+10) FieldsFunc/Mixed/65536 1.57ms ± 1% 0.61ms ± 1% -61.20% (p=0.000 n=10+10) FieldsFunc/Mixed/1048576 26.5ms ± 1% 11.4ms ± 2% -56.84% (p=0.000 n=10+10) name old speed new speed delta Fields/ASCII/16 38.4MB/s ± 4% 134.9MB/s ± 3% +251.55% (p=0.000 n=10+10) Fields/ASCII/256 43.0MB/s ± 3% 290.6MB/s ± 1% +575.97% (p=0.000 n=10+8) Fields/ASCII/4096 44.4MB/s ± 1% 320.0MB/s ± 2% +620.90% (p=0.000 n=10+10) Fields/ASCII/65536 44.0MB/s ± 1% 260.7MB/s ± 1% +493.15% (p=0.000 n=10+10) Fields/ASCII/1048576 42.0MB/s ± 1% 161.6MB/s ± 2% +285.21% (p=0.000 n=10+10) Fields/Mixed/16 39.4MB/s ± 1% 71.7MB/s ± 1% +82.20% (p=0.000 n=10+10) Fields/Mixed/256 44.3MB/s ± 1% 112.8MB/s ± 1% +154.64% (p=0.000 n=9+10) Fields/Mixed/4096 41.9MB/s ± 1% 101.2MB/s ± 3% +141.92% (p=0.000 n=10+10) Fields/Mixed/65536 41.5MB/s ± 1% 95.5MB/s ± 1% +130.29% (p=0.000 n=10+10) Fields/Mixed/1048576 39.4MB/s ± 1% 82.9MB/s ± 2% +110.28% (p=0.000 n=9+10) FieldsFunc/ASCII/16 40.5MB/s ± 1% 84.9MB/s ± 2% +109.80% (p=0.000 n=10+10) FieldsFunc/ASCII/256 43.4MB/s ± 1% 127.9MB/s ± 1% +194.58% (p=0.000 n=10+10) FieldsFunc/ASCII/4096 44.3MB/s ± 1% 124.2MB/s ± 1% +180.44% (p=0.000 n=10+9) FieldsFunc/ASCII/65536 44.2MB/s ± 1% 120.6MB/s ± 1% +173.06% (p=0.000 n=10+9) FieldsFunc/ASCII/1048576 41.8MB/s ± 1% 100.2MB/s ± 3% +139.53% (p=0.000 n=10+10) FieldsFunc/Mixed/16 39.8MB/s ± 1% 77.8MB/s ± 2% +95.46% (p=0.000 n=10+10) FieldsFunc/Mixed/256 44.9MB/s ± 1% 129.4MB/s ± 1% +187.97% (p=0.000 n=10+10) FieldsFunc/Mixed/4096 42.0MB/s ± 1% 115.6MB/s ± 1% +175.08% (p=0.000 n=10+10) FieldsFunc/Mixed/65536 41.6MB/s ± 1% 107.3MB/s ± 1% +157.75% (p=0.000 n=10+10) FieldsFunc/Mixed/1048576 39.6MB/s ± 1% 91.8MB/s ± 2% +131.72% (p=0.000 n=10+10) name old alloc/op new alloc/op delta Fields/ASCII/16 80.0B ± 0% 80.0B ± 0% ~ (all equal) Fields/ASCII/256 768B ± 0% 768B ± 0% ~ (all equal) Fields/ASCII/4096 9.47kB ± 0% 9.47kB ± 0% ~ (all equal) Fields/ASCII/65536 147kB ± 0% 147kB ± 0% ~ (all equal) Fields/ASCII/1048576 2.27MB ± 0% 2.27MB ± 0% ~ (all equal) Fields/Mixed/16 96.0B ± 0% 96.0B ± 0% ~ (all equal) Fields/Mixed/256 768B ± 0% 768B ± 0% ~ (all equal) Fields/Mixed/4096 9.47kB ± 0% 24.83kB ± 0% +162.16% (p=0.000 n=10+10) Fields/Mixed/65536 147kB ± 0% 497kB ± 0% +237.24% (p=0.000 n=10+10) Fields/Mixed/1048576 2.26MB ± 0% 9.61MB ± 0% +324.89% (p=0.000 n=10+10) FieldsFunc/ASCII/16 80.0B ± 0% 80.0B ± 0% ~ (all equal) FieldsFunc/ASCII/256 768B ± 0% 768B ± 0% ~ (all equal) FieldsFunc/ASCII/4096 9.47kB ± 0% 24.83kB ± 0% +162.16% (p=0.000 n=10+10) FieldsFunc/ASCII/65536 147kB ± 0% 497kB ± 0% +237.24% (p=0.000 n=10+10) FieldsFunc/ASCII/1048576 2.27MB ± 0% 9.61MB ± 0% +323.72% (p=0.000 n=10+10) FieldsFunc/Mixed/16 96.0B ± 0% 96.0B ± 0% ~ (all equal) FieldsFunc/Mixed/256 768B ± 0% 768B ± 0% ~ (all equal) FieldsFunc/Mixed/4096 9.47kB ± 0% 24.83kB ± 0% +162.16% (p=0.000 n=10+10) FieldsFunc/Mixed/65536 147kB ± 0% 497kB ± 0% +237.24% (p=0.000 n=10+10) FieldsFunc/Mixed/1048576 2.26MB ± 0% 9.61MB ± 0% +324.89% (p=0.000 n=10+10) name old allocs/op new allocs/op delta Fields/ASCII/16 1.00 ± 0% 1.00 ± 0% ~ (all equal) Fields/ASCII/256 1.00 ± 0% 1.00 ± 0% ~ (all equal) Fields/ASCII/4096 1.00 ± 0% 1.00 ± 0% ~ (all equal) Fields/ASCII/65536 1.00 ± 0% 1.00 ± 0% ~ (all equal) Fields/ASCII/1048576 1.00 ± 0% 1.00 ± 0% ~ (all equal) Fields/Mixed/16 1.00 ± 0% 1.00 ± 0% ~ (all equal) Fields/Mixed/256 1.00 ± 0% 1.00 ± 0% ~ (all equal) Fields/Mixed/4096 1.00 ± 0% 5.00 ± 0% +400.00% (p=0.000 n=10+10) Fields/Mixed/65536 1.00 ± 0% 12.00 ± 0% +1100.00% (p=0.000 n=10+10) Fields/Mixed/1048576 1.00 ± 0% 24.00 ± 0% +2300.00% (p=0.000 n=10+10) FieldsFunc/ASCII/16 1.00 ± 0% 1.00 ± 0% ~ (all equal) FieldsFunc/ASCII/256 1.00 ± 0% 1.00 ± 0% ~ (all equal) FieldsFunc/ASCII/4096 1.00 ± 0% 5.00 ± 0% +400.00% (p=0.000 n=10+10) FieldsFunc/ASCII/65536 1.00 ± 0% 12.00 ± 0% +1100.00% (p=0.000 n=10+10) FieldsFunc/ASCII/1048576 1.00 ± 0% 24.00 ± 0% +2300.00% (p=0.000 n=10+10) FieldsFunc/Mixed/16 1.00 ± 0% 1.00 ± 0% ~ (all equal) FieldsFunc/Mixed/256 1.00 ± 0% 1.00 ± 0% ~ (all equal) FieldsFunc/Mixed/4096 1.00 ± 0% 5.00 ± 0% +400.00% (p=0.000 n=10+10) FieldsFunc/Mixed/65536 1.00 ± 0% 12.00 ± 0% +1100.00% (p=0.000 n=10+10) FieldsFunc/Mixed/1048576 1.00 ± 0% 24.00 ± 0% +2300.00% (p=0.000 n=10+10) Change-Id: If1926782decc2f60d3b4b8c41c2ce7d8bdedfd8f Reviewed-on: https://go-review.googlesource.com/55131 Run-TryBot: Martin Möhrmann <moehrmann@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
This commit is contained in:
Martin Möhrmann
parent
dd6880d69b
commit
7df29b50b2
@ -265,9 +265,57 @@ func SplitAfter(s, sep []byte) [][]byte {
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return genSplit(s, sep, len(sep), -1)
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return genSplit(s, sep, len(sep), -1)
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}
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}
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var asciiSpace = [256]uint8{'\t': 1, '\n': 1, '\v': 1, '\f': 1, '\r': 1, ' ': 1}
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// Fields splits the slice s around each instance of one or more consecutive white space
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// Fields splits the slice s around each instance of one or more consecutive white space
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// characters, returning a slice of subslices of s or an empty list if s contains only white space.
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// characters, as defined by unicode.IsSpace, returning a slice of subslices of s or an
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// empty slice if s contains only white space.
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func Fields(s []byte) [][]byte {
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func Fields(s []byte) [][]byte {
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// First count the fields.
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// This is an exact count if s is ASCII, otherwise it is an approximation.
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n := 0
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wasSpace := 1
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// setBits is used to track which bits are set in the bytes of s.
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setBits := uint8(0)
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for i := 0; i < len(s); i++ {
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r := s[i]
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setBits |= r
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isSpace := int(asciiSpace[r])
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n += wasSpace & ^isSpace
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wasSpace = isSpace
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}
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if setBits < utf8.RuneSelf { // ASCII fast path
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a := make([][]byte, n)
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na := 0
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fieldStart := 0
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i := 0
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// Skip spaces in the front of the input.
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for i < len(s) && asciiSpace[s[i]] != 0 {
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i++
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}
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fieldStart = i
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for i < len(s) {
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if asciiSpace[s[i]] == 0 {
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i++
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continue
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}
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a[na] = s[fieldStart:i]
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na++
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i++
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// Skip spaces in between fields.
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for i < len(s) && asciiSpace[s[i]] != 0 {
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i++
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}
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fieldStart = i
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}
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if fieldStart < len(s) { // Last field might end at EOF.
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a[na] = s[fieldStart:]
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}
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return a
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}
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// Some runes in the input slice are not ASCII.
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return FieldsFunc(s, unicode.IsSpace)
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return FieldsFunc(s, unicode.IsSpace)
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}
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}
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@ -278,39 +326,49 @@ func Fields(s []byte) [][]byte {
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// FieldsFunc makes no guarantees about the order in which it calls f(c).
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// FieldsFunc makes no guarantees about the order in which it calls f(c).
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// If f does not return consistent results for a given c, FieldsFunc may crash.
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// If f does not return consistent results for a given c, FieldsFunc may crash.
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func FieldsFunc(s []byte, f func(rune) bool) [][]byte {
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func FieldsFunc(s []byte, f func(rune) bool) [][]byte {
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n := 0
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// A span is used to record a slice of s of the form s[start:end].
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inField := false
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// The start index is inclusive and the end index is exclusive.
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type span struct {
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start int
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end int
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}
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spans := make([]span, 0, 32)
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// Find the field start and end indices.
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wasField := false
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fromIndex := 0
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for i := 0; i < len(s); {
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for i := 0; i < len(s); {
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r, size := utf8.DecodeRune(s[i:])
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size := 1
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wasInField := inField
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r := rune(s[i])
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inField = !f(r)
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if r >= utf8.RuneSelf {
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if inField && !wasInField {
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r, size = utf8.DecodeRune(s[i:])
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n++
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}
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if f(r) {
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if wasField {
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spans = append(spans, span{start: fromIndex, end: i})
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wasField = false
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}
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} else {
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if !wasField {
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fromIndex = i
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wasField = true
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}
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}
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}
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i += size
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i += size
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}
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}
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a := make([][]byte, n)
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// Last field might end at EOF.
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na := 0
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if wasField {
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fieldStart := -1
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spans = append(spans, span{fromIndex, len(s)})
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for i := 0; i <= len(s) && na < n; {
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r, size := utf8.DecodeRune(s[i:])
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if fieldStart < 0 && size > 0 && !f(r) {
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fieldStart = i
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i += size
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continue
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}
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}
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if fieldStart >= 0 && (size == 0 || f(r)) {
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a[na] = s[fieldStart:i]
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// Create subslices from recorded field indices.
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na++
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a := make([][]byte, len(spans))
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fieldStart = -1
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for i, span := range spans {
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a[i] = s[span.start:span.end]
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}
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}
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if size == 0 {
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break
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return a
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}
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i += size
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}
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return a[0:na]
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}
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}
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// Join concatenates the elements of s to create a new byte slice. The separator
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// Join concatenates the elements of s to create a new byte slice. The separator
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@ -1502,19 +1502,58 @@ var makeFieldsInput = func() []byte {
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return x
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return x
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}
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}
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var fieldsInput = makeFieldsInput()
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var makeFieldsInputASCII = func() []byte {
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x := make([]byte, 1<<20)
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// Input is ~10% space, rest ASCII non-space.
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for i := range x {
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if rand.Intn(10) == 0 {
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x[i] = ' '
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} else {
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x[i] = 'x'
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}
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}
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return x
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}
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var bytesdata = []struct {
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name string
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data []byte
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}{
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{"ASCII", makeFieldsInputASCII()},
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{"Mixed", makeFieldsInput()},
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}
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func BenchmarkFields(b *testing.B) {
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func BenchmarkFields(b *testing.B) {
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b.SetBytes(int64(len(fieldsInput)))
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for _, sd := range bytesdata {
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b.Run(sd.name, func(b *testing.B) {
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for j := 1 << 4; j <= 1<<20; j <<= 4 {
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b.Run(fmt.Sprintf("%d", j), func(b *testing.B) {
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b.ReportAllocs()
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b.SetBytes(int64(j))
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data := sd.data[:j]
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for i := 0; i < b.N; i++ {
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for i := 0; i < b.N; i++ {
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Fields(fieldsInput)
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Fields(data)
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}
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})
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}
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})
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}
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}
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}
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}
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func BenchmarkFieldsFunc(b *testing.B) {
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func BenchmarkFieldsFunc(b *testing.B) {
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b.SetBytes(int64(len(fieldsInput)))
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for _, sd := range bytesdata {
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b.Run(sd.name, func(b *testing.B) {
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for j := 1 << 4; j <= 1<<20; j <<= 4 {
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b.Run(fmt.Sprintf("%d", j), func(b *testing.B) {
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b.ReportAllocs()
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b.SetBytes(int64(j))
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data := sd.data[:j]
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for i := 0; i < b.N; i++ {
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for i := 0; i < b.N; i++ {
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FieldsFunc(fieldsInput, unicode.IsSpace)
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FieldsFunc(data, unicode.IsSpace)
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}
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})
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}
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})
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}
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}
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}
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}
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