Merge pull request #46 from ninedraft/use-strings-builder

Use `strings.Builder` if it's available

common.go

@@ -3,15 +3,11 @@
 
 package xstrings
 
-import (
-	"bytes"
-)
-
 const bufferMaxInitGrowSize = 2048
 
 // Lazy initialize a buffer.
-func allocBuffer(orig, cur string) *bytes.Buffer {
-	output := &bytes.Buffer{}
+func allocBuffer(orig, cur string) *stringBuilder {
+	output := &stringBuilder{}
 	maxSize := len(orig) * 4
 
 	// Avoid to reserve too much memory at once.

convert.go

@@ -4,7 +4,6 @@
 package xstrings
 
 import (
-	"bytes"
 	"math/rand"
 	"unicode"
 	"unicode/utf8"
@@ -23,7 +22,7 @@ func ToCamelCase(str string) string {
 		return ""
 	}
 
-	buf := &bytes.Buffer{}
+	buf := &stringBuilder{}
 	var r0, r1 rune
 	var size int
 
@@ -112,7 +111,7 @@ func camelCaseToLowerCase(str string, connector rune) string {
 		return ""
 	}
 
-	buf := &bytes.Buffer{}
+	buf := &stringBuilder{}
 	wt, word, remaining := nextWord(str)
 
 	for len(remaining) > 0 {
@@ -374,7 +373,7 @@ func nextValidRune(str string, prev rune) (r rune, size int) {
 	return
 }
 
-func toLower(buf *bytes.Buffer, wt wordType, str string, connector rune) {
+func toLower(buf *stringBuilder, wt wordType, str string, connector rune) {
 	buf.Grow(buf.Len() + len(str))
 
 	if wt != upperCaseWord && wt != connectorWord {
@@ -401,7 +400,7 @@ func SwapCase(str string) string {
 	var r rune
 	var size int
 
-	buf := &bytes.Buffer{}
+	buf := &stringBuilder{}
 
 	for len(str) > 0 {
 		r, size = utf8.DecodeRuneInString(str)
@@ -435,7 +434,7 @@ func FirstRuneToUpper(str string) string {
 		return str
 	}
 
-	buf := &bytes.Buffer{}
+	buf := &stringBuilder{}
 	buf.WriteRune(unicode.ToUpper(r))
 	buf.WriteString(str[size:])
 	return buf.String()
@@ -453,7 +452,7 @@ func FirstRuneToLower(str string) string {
 		return str
 	}
 
-	buf := &bytes.Buffer{}
+	buf := &stringBuilder{}
 	buf.WriteRune(unicode.ToLower(r))
 	buf.WriteString(str[size:])
 	return buf.String()
@@ -566,7 +565,7 @@ func Successor(str string) string {
 
 	// Needs to add one character for carry.
 	if i < 0 && carry != ' ' {
-		buf := &bytes.Buffer{}
+		buf := &stringBuilder{}
 		buf.Grow(l + 4) // Reserve enough space for write.
 
 		if lastAlphanumeric != 0 {

count_test.go

@@ -31,9 +31,9 @@ func TestWordCount(t *testing.T) {
 		"中文":                      "0",
 		"你好，sekai！":               "1",
 		"oh, it's super-fancy!!a": "4",
-		"":        "0",
-		"-":       "0",
-		"it's-'s": "1",
+		"":                        "0",
+		"-":                       "0",
+		"it's-'s":                 "1",
 	})
 }
 
@@ -45,7 +45,7 @@ func TestWidth(t *testing.T) {
 	runTestCases(t, runner, _M{
 		"abcd\t0123\n7890": "12",
 		"中zh英eng文混排":       "15",
-		"": "0",
+		"":                 "0",
 	})
 }
 

format.go

@@ -4,7 +4,6 @@
 package xstrings
 
 import (
-	"bytes"
 	"unicode/utf8"
 )
 
@@ -28,7 +27,7 @@ func ExpandTabs(str string, tabSize int) string {
 
 	var r rune
 	var i, size, column, expand int
-	var output *bytes.Buffer
+	var output *stringBuilder
 
 	orig := str
 
@@ -43,7 +42,7 @@ func ExpandTabs(str string, tabSize int) string {
 			}
 
 			for i = 0; i < expand; i++ {
-				output.WriteByte(byte(' '))
+				output.WriteRune(' ')
 			}
 
 			column += expand
@@ -88,7 +87,7 @@ func LeftJustify(str string, length int, pad string) string {
 	remains := length - l
 	padLen := Len(pad)
 
-	output := &bytes.Buffer{}
+	output := &stringBuilder{}
 	output.Grow(len(str) + (remains/padLen+1)*len(pad))
 	output.WriteString(str)
 	writePadString(output, pad, padLen, remains)
@@ -114,7 +113,7 @@ func RightJustify(str string, length int, pad string) string {
 	remains := length - l
 	padLen := Len(pad)
 
-	output := &bytes.Buffer{}
+	output := &stringBuilder{}
 	output.Grow(len(str) + (remains/padLen+1)*len(pad))
 	writePadString(output, pad, padLen, remains)
 	output.WriteString(str)
@@ -140,15 +139,15 @@ func Center(str string, length int, pad string) string {
 	remains := length - l
 	padLen := Len(pad)
 
-	output := &bytes.Buffer{}
+	output := &stringBuilder{}
 	output.Grow(len(str) + (remains/padLen+1)*len(pad))
 	writePadString(output, pad, padLen, remains/2)
 	output.WriteString(str)
 	writePadString(output, pad, padLen, (remains+1)/2)
 	return output.String()
 }
 
-func writePadString(output *bytes.Buffer, pad string, padLen, remains int) {
+func writePadString(output *stringBuilder, pad string, padLen, remains int) {
 	var r rune
 	var size int
 

manipulate.go

@@ -4,7 +4,6 @@
 package xstrings
 
 import (
-	"bytes"
 	"strings"
 	"unicode/utf8"
 )
@@ -131,7 +130,7 @@ func Insert(dst, src string, index int) string {
 // Scrub scrubs invalid utf8 bytes with repl string.
 // Adjacent invalid bytes are replaced only once.
 func Scrub(str, repl string) string {
-	var buf *bytes.Buffer
+	var buf *stringBuilder
 	var r rune
 	var size, pos int
 	var hasError bool
@@ -144,7 +143,7 @@ func Scrub(str, repl string) string {
 		if r == utf8.RuneError {
 			if !hasError {
 				if buf == nil {
-					buf = &bytes.Buffer{}
+					buf = &stringBuilder{}
 				}
 
 				buf.WriteString(origin[:pos])

stringbuilder.go

@@ -0,0 +1,7 @@
+//+build go1.10
+
+package xstrings
+
+import "strings"
+
+type stringBuilder = strings.Builder

stringbuilder_go110.go

@@ -0,0 +1,9 @@
+//+build !go1.10
+
+package xstrings
+
+import "bytes"
+
+type stringBuilder struct {
+	bytes.Buffer
+}

translate.go

@@ -4,7 +4,6 @@
 package xstrings
 
 import (
-	"bytes"
 	"unicode"
 	"unicode/utf8"
 )
@@ -303,7 +302,7 @@ func (tr *Translator) Translate(str string) string {
 
 	orig := str
 
-	var output *bytes.Buffer
+	var output *stringBuilder
 
 	for len(str) > 0 {
 		r, size = utf8.DecodeRuneInString(str)
@@ -500,7 +499,7 @@ func Squeeze(str, pattern string) string {
 	var size int
 	var skipSqueeze, matched bool
 	var tr *Translator
-	var output *bytes.Buffer
+	var output *stringBuilder
 
 	orig := str
 	last = -1