Add: StringUtils.Substring

FileUtils.go

@@ -0,0 +1,53 @@
+package golanghelper
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"os"
+)
+
+type FileUtils struct {
+}
+
+func (f *FileUtils) CopyFile(srcFilePath, destFilePath string, isOverwrite bool) (err error) {
+	var srcFileInfo os.FileInfo
+	srcFileInfo, err = os.Stat(srcFilePath)
+	if err != nil {
+		return
+	}
+	if !srcFileInfo.Mode().IsRegular() {
+		return errors.New(fmt.Sprintf("%s is not a regular file", srcFileInfo.Name()))
+	}
+
+	var isNotExist bool
+	_, err = os.Stat(destFilePath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			isNotExist = true
+		} else {
+			return
+		}
+	}
+
+	var destFile *os.File
+	if isNotExist == false && isOverwrite == false {
+		return errors.New("File already exists")
+	}
+
+	destFile, err = os.Create(destFilePath)
+	if err != nil {
+		return
+	}
+	defer destFile.Close()
+
+	sourceFile, err := os.Open(srcFilePath)
+	if err != nil {
+		return
+	}
+	defer sourceFile.Close()
+
+	_, err = io.Copy(destFile, sourceFile)
+
+	return
+}

JSONObject.go

@@ -0,0 +1,25 @@
+package golanghelper
+
+import (
+	"encoding/json"
+)
+
+type JSONObject struct {
+	Data []byte
+}
+
+func NewJSONObject(object interface{}) (jsonObject JSONObject, err error) {
+	var data []byte
+	data, err = json.Marshal(object)
+	if err != nil {
+		return
+	}
+
+	jsonObject = JSONObject{Data: data}
+
+	return
+}
+
+func (j *JSONObject) ToString() string {
+	return string(j.Data)
+}

StringUtils.go

@@ -33,3 +33,36 @@ func (s *StringUtils) LeftPad(str string, size int, padStr string) string {
 
 	return strings.Repeat(padStr, padCount) + str
 }
+
+func (s *StringUtils) Substring(str string, start, end int) string {
+	if str == "" {
+		return str
+	}
+
+	runes := []rune(str)
+
+	if end < 0 {
+		end = len(runes) + end
+	}
+	if start < 0 {
+		start = len(runes) + start
+	}
+
+	if end > len(str) {
+		end = len(str)
+	}
+
+	if start > end {
+		return EMPTY
+	}
+
+	if start < 0 {
+		start = 0
+	}
+
+	if end < 0 {
+		end = 0
+	}
+
+	return string(runes[start:end])
+}

StringUtils_test.go

@@ -0,0 +1,51 @@
+package golanghelper_test
+
+import (
+	"testing"
+
+	"gitlab-ce.niaulang.com/niau-lang/golanghelper"
+)
+
+func TestSubstring(t *testing.T) {
+	stringUtils := golanghelper.StringUtils{}
+
+	s := stringUtils.Substring("", 0, 0)
+	if s != "" {
+		t.Errorf("預期的值為空字串, 卻回傳 %v", s)
+	}
+
+	s = stringUtils.Substring("abc", 0, 2)
+	if s != "ab" {
+		t.Errorf("預期的值為 ab, 卻回傳 %v", s)
+	}
+
+	s = stringUtils.Substring("abc", 2, 0)
+	if s != "" {
+		t.Errorf("預期的值為空字串, 卻回傳 %v", s)
+	}
+
+	s = stringUtils.Substring("abc", 2, 4)
+	if s != "c" {
+		t.Errorf("預期的值為 c, 卻回傳 %v", s)
+	}
+
+	s = stringUtils.Substring("abc", 4, 6)
+	if s != "" {
+		t.Errorf("預期的值為空字串, 卻回傳 %v", s)
+	}
+
+	s = stringUtils.Substring("abc", 2, 2)
+	if s != "" {
+		t.Errorf("預期的值為 ab, 卻回傳 %v", s)
+	}
+
+	s = stringUtils.Substring("abc", -2, -1)
+	if s != "b" {
+		t.Errorf("預期的值為 b, 卻回傳 %v", s)
+	}
+
+	s = stringUtils.Substring("abc", -4, 2)
+	if s != "ab" {
+		t.Errorf("預期的值為 ab, 卻回傳 %v", s)
+	}
+}