small string split join optimization

internal/utils/strutils/parser.go

@@ -2,8 +2,6 @@ package strutils
 
 import (
 	"reflect"
-
-	"github.com/yusing/go-proxy/internal/logging"
 )
 
 type Parser interface {
@@ -22,7 +20,7 @@ func Parse[T Parser](from string) (t T, err error) {
 func MustParse[T Parser](from string) T {
 	t, err := Parse[T](from)
 	if err != nil {
-		logging.Panic().Err(err).Msg("must failed")
+		panic("must failed: " + err.Error())
 	}
 	return t
 }

internal/utils/strutils/split_join.go

@@ -0,0 +1,81 @@
+package strutils
+
+import (
+	"math"
+	"strings"
+)
+
+// SplitRune is like strings.Split but takes a rune as separator.
+func SplitRune(s string, sep rune) []string {
+	if sep == 0 {
+		return strings.Split(s, "")
+	}
+	n := strings.Count(s, string(sep)) + 1
+	if n > len(s)+1 {
+		n = len(s) + 1
+	}
+	a := make([]string, n)
+	n--
+	i := 0
+	for i < n {
+		m := strings.IndexRune(s, sep)
+		if m < 0 {
+			break
+		}
+		a[i] = s[:m]
+		s = s[m+1:]
+		i++
+	}
+	a[i] = s
+	return a[:i+1]
+}
+
+// SplitComma is a wrapper around SplitRune(s, ',').
+func SplitComma(s string) []string {
+	return SplitRune(s, ',')
+}
+
+// SplitLine is a wrapper around SplitRune(s, '\n').
+func SplitLine(s string) []string {
+	return SplitRune(s, '\n')
+}
+
+// SplitSpace is a wrapper around SplitRune(s, ' ').
+func SplitSpace(s string) []string {
+	return SplitRune(s, ' ')
+}
+
+// JoinRune is like strings.Join but takes a rune as separator.
+func JoinRune(elems []string, sep rune) string {
+	switch len(elems) {
+	case 0:
+		return ""
+	case 1:
+		return elems[0]
+	}
+	if sep == 0 {
+		return strings.Join(elems, "")
+	}
+
+	var n int
+	for _, elem := range elems {
+		if len(elem) > math.MaxInt-n {
+			panic("strings: Join output length overflow")
+		}
+		n += len(elem)
+	}
+
+	var b strings.Builder
+	b.Grow(n)
+	b.WriteString(elems[0])
+	for _, s := range elems[1:] {
+		b.WriteRune(sep)
+		b.WriteString(s)
+	}
+	return b.String()
+}
+
+// JoinLines is a wrapper around JoinRune(elems, '\n').
+func JoinLines(elems []string) string {
+	return JoinRune(elems, '\n')
+}

internal/utils/strutils/split_join_test.go

@@ -0,0 +1,38 @@
+package strutils_test
+
+import (
+	"strings"
+	"testing"
+
+	. "github.com/yusing/go-proxy/internal/utils/strutils"
+	. "github.com/yusing/go-proxy/internal/utils/testing"
+)
+
+var alphaNumeric = func() string {
+	var s strings.Builder
+	for i := range 'z' - 'a' + 1 {
+		s.WriteRune('a' + i)
+		s.WriteRune('A' + i)
+		s.WriteRune(',')
+	}
+	for i := range '9' - '0' + 1 {
+		s.WriteRune('0' + i)
+		s.WriteRune(',')
+	}
+	return s.String()
+}()
+
+func TestSplit(t *testing.T) {
+	tests := map[string]rune{
+		"":  0,
+		"1": '1',
+		",": ',',
+	}
+	for sep, rsep := range tests {
+		t.Run(sep, func(t *testing.T) {
+			expected := strings.Split(alphaNumeric, sep)
+			ExpectDeepEqual(t, SplitRune(alphaNumeric, rsep), expected)
+			ExpectEqual(t, JoinRune(expected, rsep), alphaNumeric)
+		})
+	}
+}

internal/utils/strutils/strconv.go

@@ -1,17 +1,7 @@
 package strutils
 
 import (
-	"errors"
 	"strconv"
-
-	E "github.com/yusing/go-proxy/internal/error"
 )
 
-func Atoi(s string) (int, E.Error) {
-	val, err := strconv.Atoi(s)
-	if err != nil {
-		return val, E.From(errors.Unwrap(err)).Subject(s)
-	}
-
-	return val, nil
-}
+var Atoi = strconv.Atoi

internal/utils/strutils/string.go

@@ -8,8 +8,10 @@ import (
 	"golang.org/x/text/language"
 )
 
+// CommaSeperatedList returns a list of strings split by commas,
+// then trim spaces from each element.
 func CommaSeperatedList(s string) []string {
-	res := strings.Split(s, ",")
+	res := SplitComma(s)
 	for i, part := range res {
 		res[i] = strings.TrimSpace(part)
 	}