fmt, fmtsort: refactor SortedMap to use slice of structs for map sorting

This change refactors the SortedMap type in the fmtsort package from using two parallel slices for keys and values to a single slice of structs. This improves code clarity and reduces the complexity of handling map entries. Affected files and their respective functions have been updated to work with the new structure, including adjustments in fmt/print.go and text/template/exec.go to iterate over the new map representation. goos: darwin goarch: arm64 pkg: fmt cpu: Apple M2 Max │ old.txt │ new.txt │ │ sec/op │ sec/op vs base │ SprintfPadding-12 22.90n ± 14% 22.49n ± 5% ~ (p=0.481 n=10) SprintfEmpty-12 3.448n ± 8% 3.070n ± 11% -10.98% (p=0.029 n=10) SprintfString-12 7.635n ± 23% 7.567n ± 22% ~ (p=0.529 n=10) SprintfTruncateString-12 14.81n ± 8% 15.32n ± 9% ~ (p=0.315 n=10) SprintfTruncateBytes-12 14.19n ± 13% 15.72n ± 11% ~ (p=0.089 n=10) SprintfSlowParsingPath-12 9.048n ± 14% 9.271n ± 16% ~ (p=0.971 n=10) SprintfQuoteString-12 42.24n ± 6% 41.38n ± 5% ~ (p=0.143 n=10) SprintfInt-12 6.727n ± 16% 6.451n ± 14% ~ (p=0.239 n=10) SprintfIntInt-12 10.92n ± 15% 10.37n ± 10% ~ (p=0.063 n=10) SprintfPrefixedInt-12 31.47n ± 4% 30.71n ± 5% ~ (p=0.404 n=10) SprintfFloat-12 13.69n ± 10% 14.88n ± 11% ~ (p=0.171 n=10) SprintfComplex-12 51.06n ± 11% 50.50n ± 5% ~ (p=0.280 n=10) SprintfBoolean-12 7.432n ± 18% 7.566n ± 19% ~ (p=0.436 n=10) SprintfHexString-12 36.58n ± 14% 35.70n ± 2% ~ (p=0.072 n=10) SprintfHexBytes-12 48.01n ± 3% 47.04n ± 3% ~ (p=0.051 n=10) SprintfBytes-12 63.90n ± 7% 61.83n ± 3% ~ (p=0.123 n=10) SprintfStringer-12 37.36n ± 9% 39.58n ± 11% ~ (p=0.529 n=10) SprintfStructure-12 162.6n ± 3% 135.8n ± 5% -16.51% (p=0.000 n=10) ManyArgs-12 35.49n ± 18% 31.10n ± 31% ~ (p=0.971 n=10) FprintInt-12 33.48n ± 3% 33.30n ± 1% -0.54% (p=0.014 n=10) FprintfBytes-12 48.36n ± 1% 49.13n ± 2% +1.59% (p=0.002 n=10) FprintIntNoAlloc-12 33.44n ± 0% 33.24n ± 1% ~ (p=0.280 n=10) ScanInts-12 130.8µ ± 1% 132.4µ ± 2% +1.22% (p=0.000 n=10) ScanRecursiveInt-12 40.16m ± 2% 40.52m ± 2% ~ (p=0.052 n=10) ScanRecursiveIntReaderWrapper-12 40.15m ± 1% 41.22m ± 1% +2.68% (p=0.000 n=10) geomean 101.9n 100.7n -1.24% │ old.txt │ new.txt │ │ B/op │ B/op vs base │ SprintfPadding-12 16.00 ± 0% 16.00 ± 0% ~ (p=1.000 n=10) ¹ SprintfEmpty-12 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=10) ¹ SprintfString-12 5.000 ± 0% 5.000 ± 0% ~ (p=1.000 n=10) ¹ SprintfTruncateString-12 16.00 ± 0% 16.00 ± 0% ~ (p=1.000 n=10) ¹ SprintfTruncateBytes-12 16.00 ± 0% 16.00 ± 0% ~ (p=1.000 n=10) ¹ SprintfSlowParsingPath-12 5.000 ± 0% 5.000 ± 0% ~ (p=1.000 n=10) ¹ SprintfQuoteString-12 32.00 ± 0% 32.00 ± 0% ~ (p=1.000 n=10) ¹ SprintfInt-12 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=10) ¹ SprintfIntInt-12 3.000 ± 0% 3.000 ± 0% ~ (p=1.000 n=10) ¹ SprintfPrefixedInt-12 64.00 ± 0% 64.00 ± 0% ~ (p=1.000 n=10) ¹ SprintfFloat-12 8.000 ± 0% 8.000 ± 0% ~ (p=1.000 n=10) ¹ SprintfComplex-12 24.00 ± 0% 24.00 ± 0% ~ (p=1.000 n=10) ¹ SprintfBoolean-12 4.000 ± 0% 4.000 ± 0% ~ (p=1.000 n=10) ¹ SprintfHexString-12 80.00 ± 0% 80.00 ± 0% ~ (p=1.000 n=10) ¹ SprintfHexBytes-12 104.0 ± 0% 104.0 ± 0% ~ (p=1.000 n=10) ¹ SprintfBytes-12 88.00 ± 0% 88.00 ± 0% ~ (p=1.000 n=10) ¹ SprintfStringer-12 32.00 ± 0% 32.00 ± 0% ~ (p=1.000 n=10) ¹ SprintfStructure-12 216.0 ± 0% 168.0 ± 0% -22.22% (p=0.000 n=10) ManyArgs-12 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=10) ¹ FprintInt-12 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=10) ¹ FprintfBytes-12 24.00 ± 0% 24.00 ± 0% ~ (p=1.000 n=10) ¹ FprintIntNoAlloc-12 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=10) ¹ ScanInts-12 14.87Ki ± 0% 14.87Ki ± 0% ~ (p=1.000 n=10) ¹ ScanRecursiveInt-12 16.32Ki ± 7% 16.94Ki ± 4% ~ (p=0.441 n=10) ScanRecursiveIntReaderWrapper-12 16.33Ki ± 1% 16.35Ki ± 8% ~ (p=0.068 n=10) geomean ² -0.84% ² ¹ all samples are equal ² summaries must be >0 to compute geomean │ old.txt │ new.txt │ │ allocs/op │ allocs/op vs base │ SprintfPadding-12 1.000 ± 0% 1.000 ± 0% ~ (p=1.000 n=10) ¹ SprintfEmpty-12 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=10) ¹ SprintfString-12 1.000 ± 0% 1.000 ± 0% ~ (p=1.000 n=10) ¹ SprintfTruncateString-12 1.000 ± 0% 1.000 ± 0% ~ (p=1.000 n=10) ¹ SprintfTruncateBytes-12 1.000 ± 0% 1.000 ± 0% ~ (p=1.000 n=10) ¹ SprintfSlowParsingPath-12 1.000 ± 0% 1.000 ± 0% ~ (p=1.000 n=10) ¹ SprintfQuoteString-12 1.000 ± 0% 1.000 ± 0% ~ (p=1.000 n=10) ¹ SprintfInt-12 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=10) ¹ SprintfIntInt-12 1.000 ± 0% 1.000 ± 0% ~ (p=1.000 n=10) ¹ SprintfPrefixedInt-12 1.000 ± 0% 1.000 ± 0% ~ (p=1.000 n=10) ¹ SprintfFloat-12 1.000 ± 0% 1.000 ± 0% ~ (p=1.000 n=10) ¹ SprintfComplex-12 1.000 ± 0% 1.000 ± 0% ~ (p=1.000 n=10) ¹ SprintfBoolean-12 1.000 ± 0% 1.000 ± 0% ~ (p=1.000 n=10) ¹ SprintfHexString-12 1.000 ± 0% 1.000 ± 0% ~ (p=1.000 n=10) ¹ SprintfHexBytes-12 2.000 ± 0% 2.000 ± 0% ~ (p=1.000 n=10) ¹ SprintfBytes-12 2.000 ± 0% 2.000 ± 0% ~ (p=1.000 n=10) ¹ SprintfStringer-12 4.000 ± 0% 4.000 ± 0% ~ (p=1.000 n=10) ¹ SprintfStructure-12 8.000 ± 0% 6.000 ± 0% -25.00% (p=0.000 n=10) ManyArgs-12 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=10) ¹ FprintInt-12 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=10) ¹ FprintfBytes-12 1.000 ± 0% 1.000 ± 0% ~ (p=1.000 n=10) ¹ FprintIntNoAlloc-12 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=10) ¹ ScanInts-12 1.590k ± 0% 1.590k ± 0% ~ (p=1.000 n=10) ¹ ScanRecursiveInt-12 1.592k ± 0% 1.593k ± 0% ~ (p=0.650 n=10) ScanRecursiveIntReaderWrapper-12 1.594k ± 0% 1.594k ± 0% ~ (p=0.582 n=10) geomean ² -1.14% ² ¹ all samples are equal ² summaries must be >0 to compute geomean
golang · May 9, 2024 · 5a4afcf · 5a4afcf
1 parent 4ed358b
commit 5a4afcf
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Showing 4 changed files with 23 additions and 30 deletions.
diff --git a/src/fmt/print.go b/src/fmt/print.go
@@ -814,17 +814,17 @@ func (p *pp) printValue(value reflect.Value, verb rune, depth int) {
 			p.buf.writeString(mapString)
 		}
 		sorted := fmtsort.Sort(f)
-		for i, key := range sorted.Key {
+		for i, m := range sorted {
 			if i > 0 {
 				if p.fmt.sharpV {
 					p.buf.writeString(commaSpaceString)
 				} else {
 					p.buf.writeByte(' ')
 				}
 			}
-			p.printValue(key, verb, depth+1)
+			p.printValue(m.Key, verb, depth+1)
 			p.buf.writeByte(':')
-			p.printValue(sorted.Value[i], verb, depth+1)
+			p.printValue(m.Value, verb, depth+1)
 		}
 		if p.fmt.sharpV {
 			p.buf.writeByte('}')

diff --git a/src/internal/fmtsort/sort.go b/src/internal/fmtsort/sort.go
@@ -10,24 +10,21 @@ package fmtsort
 
 import (
 	"reflect"
-	"sort"
+	"slices"
 )
 
 // Note: Throughout this package we avoid calling reflect.Value.Interface as
 // it is not always legal to do so and it's easier to avoid the issue than to face it.
 
-// SortedMap represents a map's keys and values. The keys and values are
-// aligned in index order: Value[i] is the value in the map corresponding to Key[i].
-type SortedMap struct {
-	Key   []reflect.Value
-	Value []reflect.Value
-}
+// SortedMap is a slice of KeyValue pairs that simplifies sorting
+// and iterating over map entries.
+//
+// Each KeyValue pair contains a map key and its corresponding value.
+type SortedMap []KeyValue
 
-func (o *SortedMap) Len() int           { return len(o.Key) }
-func (o *SortedMap) Less(i, j int) bool { return compare(o.Key[i], o.Key[j]) < 0 }
-func (o *SortedMap) Swap(i, j int) {
-	o.Key[i], o.Key[j] = o.Key[j], o.Key[i]
-	o.Value[i], o.Value[j] = o.Value[j], o.Value[i]
+// KeyValue holds a single key and value pair found in a map.
+type KeyValue struct {
+	Key, Value reflect.Value
 }
 
 // Sort accepts a map and returns a SortedMap that has the same keys and
@@ -48,26 +45,22 @@ func (o *SortedMap) Swap(i, j int) {
 //     Otherwise identical arrays compare by length.
 //   - interface values compare first by reflect.Type describing the concrete type
 //     and then by concrete value as described in the previous rules.
-func Sort(mapValue reflect.Value) *SortedMap {
+func Sort(mapValue reflect.Value) SortedMap {
 	if mapValue.Type().Kind() != reflect.Map {
 		return nil
 	}
 	// Note: this code is arranged to not panic even in the presence
 	// of a concurrent map update. The runtime is responsible for
 	// yelling loudly if that happens. See issue 33275.
 	n := mapValue.Len()
-	key := make([]reflect.Value, 0, n)
-	value := make([]reflect.Value, 0, n)
+	sorted := make(SortedMap, 0, n)
 	iter := mapValue.MapRange()
 	for iter.Next() {
-		key = append(key, iter.Key())
-		value = append(value, iter.Value())
-	}
-	sorted := &SortedMap{
-		Key:   key,
-		Value: value,
+		sorted = append(sorted, KeyValue{iter.Key(), iter.Value()})
 	}
-	sort.Stable(sorted)
+	slices.SortStableFunc(sorted, func(a, b KeyValue) int {
+		return compare(a.Key, b.Key)
+	})
 	return sorted
 }
 

diff --git a/src/internal/fmtsort/sort_test.go b/src/internal/fmtsort/sort_test.go
@@ -142,13 +142,13 @@ func sprint(data any) string {
 		return "nil"
 	}
 	b := new(strings.Builder)
-	for i, key := range om.Key {
+	for i, m := range om {
 		if i > 0 {
 			b.WriteRune(' ')
 		}
-		b.WriteString(sprintKey(key))
+		b.WriteString(sprintKey(m.Key))
 		b.WriteRune(':')
-		fmt.Fprint(b, om.Value[i])
+		fmt.Fprint(b, m.Value)
 	}
 	return b.String()
 }

diff --git a/src/text/template/exec.go b/src/text/template/exec.go
@@ -408,8 +408,8 @@ func (s *state) walkRange(dot reflect.Value, r *parse.RangeNode) {
 			break
 		}
 		om := fmtsort.Sort(val)
-		for i, key := range om.Key {
-			oneIteration(key, om.Value[i])
+		for _, m := range om {
+			oneIteration(m.Key, m.Value)
 		}
 		return
 	case reflect.Chan: