refactor: packages to pkg

pkg/tools/string.go

@@ -0,0 +1,106 @@
+package tools
+
+import (
+	"crypto/md5"
+	"crypto/rand"
+	"fmt"
+	"io"
+	"reflect"
+	"strings"
+	"unicode/utf8"
+)
+
+// Empty 类似于 PHP 的 empty() 函数
+func Empty(val interface{}) bool {
+	if val == nil {
+		return true
+	}
+	v := reflect.ValueOf(val)
+	switch v.Kind() {
+	case reflect.String, reflect.Array:
+		return v.Len() == 0
+	case reflect.Map, reflect.Slice:
+		return v.Len() == 0 || v.IsNil()
+	case reflect.Bool:
+		return !v.Bool()
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return v.Int() == 0
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return v.Uint() == 0
+	case reflect.Float32, reflect.Float64:
+		return v.Float() == 0
+	case reflect.Interface, reflect.Ptr:
+		return v.IsNil()
+	}
+	return reflect.DeepEqual(val, reflect.Zero(v.Type()).Interface())
+}
+
+// FirstElement 安全地获取 args[0]，避免 panic: runtime error: index out of range
+func FirstElement(args []string) string {
+	if len(args) > 0 {
+		return args[0]
+	}
+	return ""
+}
+
+// RandomNumber 生成长度为 length 随机数字字符串
+func RandomNumber(length int) string {
+	table := [...]byte{'1', '2', '3', '4', '5', '6', '7', '8', '9', '0'}
+	b := make([]byte, length)
+	n, err := io.ReadAtLeast(rand.Reader, b, length)
+	if n != length {
+		panic(err)
+	}
+	for i := 0; i < len(b); i++ {
+		b[i] = table[int(b[i])%len(table)]
+	}
+	return string(b)
+}
+
+// RandomString 生成长度为 length 的随机字符串
+func RandomString(length int) string {
+	b := make([]byte, length)
+	_, err := rand.Read(b)
+	if err != nil {
+		panic(err)
+	}
+	letters := "1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	for i, v := range b {
+		b[i] = letters[v%byte(len(letters))]
+	}
+	return string(b)
+}
+
+// MD5 生成字符串的 MD5 值
+func MD5(str string) string {
+	return fmt.Sprintf("%x", md5.Sum([]byte(str)))
+}
+
+// FormatBytes 格式化bytes
+func FormatBytes(size float64) string {
+	units := []string{"B", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB"}
+
+	i := 0
+	for ; size >= 1024 && i < len(units); i++ {
+		size /= 1024
+	}
+
+	return fmt.Sprintf("%.2f %s", size, units[i])
+}
+
+// Cut 裁剪字符串
+func Cut(str, begin, end string) string {
+	bIndex := strings.Index(str, begin)
+	eIndex := strings.Index(str, end)
+	if bIndex == -1 || eIndex == -1 || bIndex > eIndex {
+		return ""
+	}
+
+	b := utf8.RuneCountInString(str[:bIndex]) + utf8.RuneCountInString(begin)
+	e := utf8.RuneCountInString(str[:eIndex])
+	if b > e {
+		return ""
+	}
+
+	return string([]rune(str)[b:e])
+}