From c2d160663c9c1b9fe78236564dfa0758ab70a5b4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E8=8B=8F=E5=B0=B9=E5=B2=9A?= <770236076@qq.com>
Date: Fri, 13 Mar 2020 10:26:49 +0800
Subject: [PATCH] =?UTF-8?q?=E6=96=B0=E5=A2=9E=E5=8E=BB=E9=99=A4=E4=B9=B1?=
 =?UTF-8?q?=E7=A0=81=E7=9A=84=E9=95=BF=E5=BA=A6=E9=99=90=E5=88=B6=E5=87=BD?=
 =?UTF-8?q?=E6=95=B0?=
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---
 utils/utils.go | 83 +++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 79 insertions(+), 4 deletions(-)

diff --git a/utils/utils.go b/utils/utils.go
index 5ed07c5d..99e81c2b 100644
--- a/utils/utils.go
+++ b/utils/utils.go
@@ -1,6 +1,7 @@
 package utils
 
 import (
+	"bytes"
 	"encoding/base64"
 	"net/http"
 	"reflect"
@@ -287,15 +288,44 @@ func LimitStringLen(str string, maxByteCount int) (limitedStr string) {
 
 // 限制的是字符数，不是字节数
 func LimitUTF8StringLen(str string, maxRuneCount int) (limitedStr string) {
+	str2 := ""
+	bs := []byte(str)
+	bl := 0
+	for i := len(bs) - 1; i >= 0; i-- {
+		switch {
+		case bs[i] >= 0 && bs[i] <= 127:
+			return string(bs[:i+1])
+		case bs[i] >= 128 && bs[i] <= 191:
+			bl++
+		case bs[i] >= 192 && bs[i] <= 253:
+			cl := 0
+			switch {
+			case bs[i]&252 == 252:
+				cl = 6
+			case bs[i]&248 == 248:
+				cl = 5
+			case bs[i]&240 == 240:
+				cl = 4
+			case bs[i]&224 == 224:
+				cl = 3
+			default:
+				cl = 2
+			}
+			if bl+1 == cl {
+				str2 = string(bs[:i+cl])
+			}
+			str2 = string(bs[:i])
+		}
+	}
 	if maxRuneCount > 0 {
-		if len(str) > maxRuneCount {
-			runeList := []rune(str)
+		if len(str2) > maxRuneCount {
+			runeList := []rune(str2)
 			if len(runeList) > maxRuneCount {
-				str = string(runeList[:maxRuneCount])
+				str2 = string(runeList[:maxRuneCount])
 			}
 		}
 	}
-	return str
+	return str2
 }
 
 // 限制的是字节数，正常处理乱码
@@ -337,3 +367,48 @@ func LimitMixedStringLen(str string, maxByteCount int) (limitedStr string) {
 	}
 	return ""
 }
+
+// 限制的是字符数，不是字节数
+func LimitUTF8StringLen2(str string, maxRuneCount int) (limitedStr string) {
+	str2 := ""
+	bs := []byte(str)
+	bl := 0
+	for i := len(bs) - 1; i >= 0; i-- {
+		switch {
+		case bs[i] >= 0 && bs[i] <= 127 && bs[i] != 42 && bs[i] != 40 && bs[i] != 41:
+			bs2 := bs[:i]
+			bs3 := bs[i+1:]
+			bs4 := [][]byte{bs2, bs3}
+			return string(bytes.Join(bs4, []byte("")))
+		case bs[i] >= 128 && bs[i] <= 191:
+			bl++
+		case bs[i] >= 192 && bs[i] <= 253:
+			cl := 0
+			switch {
+			case bs[i]&252 == 252:
+				cl = 6
+			case bs[i]&248 == 248:
+				cl = 5
+			case bs[i]&240 == 240:
+				cl = 4
+			case bs[i]&224 == 224:
+				cl = 3
+			default:
+				cl = 2
+			}
+			if bl+1 == cl {
+				str2 = string(bs[:i+cl])
+			}
+			str2 = string(bs[:i])
+		}
+	}
+	if maxRuneCount > 0 {
+		if len(str2) > maxRuneCount {
+			runeList := []rune(str2)
+			if len(runeList) > maxRuneCount {
+				str2 = string(runeList[:maxRuneCount])
+			}
+		}
+	}
+	return str2
+}