From 1250b33220b21f994238f29c4bdb7aa130d25974 Mon Sep 17 00:00:00 2001
From: botphp <wec.cloud@gmail.com>
Date: Fri, 24 Jul 2020 09:48:51 +0800
Subject: [PATCH] =?UTF-8?q?=E5=B0=86=E6=AD=A3=E5=88=99=E7=A7=BB=E5=88=B0?=
 =?UTF-8?q?=E5=85=A8=E5=B1=80=E6=8F=90=E9=AB=98=E6=95=88=E7=8E=87?=
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---
 text/gstr/gstr_case.go | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/text/gstr/gstr_case.go b/text/gstr/gstr_case.go
index 79d4eb3cc..e264f1e2a 100644
--- a/text/gstr/gstr_case.go
+++ b/text/gstr/gstr_case.go
@@ -14,6 +14,7 @@
 //   | DelimitedScreamingCase(s, '.')    | ANY.KIND.OF.STRING |
 //   | CamelCase(s)                      | AnyKindOfString    |
 //   | CamelLowerCase(s)                 | anyKindOfString    |
+//   | SnakeFirstUpperCase(RGBCodeMd5)   | rgb_code_md5       |
 
 package gstr
 
@@ -25,6 +26,9 @@ import (
 var (
 	numberSequence    = regexp.MustCompile(`([a-zA-Z])(\d+)([a-zA-Z]?)`)
 	numberReplacement = []byte(`$1 $2 $3`)
+
+	firstCamelCaseStart = regexp.MustCompile(`([A-Z]+)([A-Z]?[_a-z\d]+)|$`)
+	firstCamelCaseEnd   = regexp.MustCompile(`([\w\W]*?)([_]?[A-Z]+)$`)
 )
 
 // CamelCase converts a string to CamelCase.
@@ -55,21 +59,20 @@ func SnakeScreamingCase(s string) string {
 
 // SnakeFirstUpperCase converts a string from RGBCodeMd5 to rgb_code_md5.
 // The length of word should not be too long
+// TODO for efficiency should change regexp to traversing string in future
 func SnakeFirstUpperCase(word string, underscore ...string) string {
 	replace := "_"
 	if len(underscore) > 0 {
 		replace = underscore[0]
 	}
 
-	r := regexp.MustCompile(`([\w\W]*?)([_]?[A-Z]+)$`)
-	m := r.FindAllStringSubmatch(word, 1)
+	m := firstCamelCaseEnd.FindAllStringSubmatch(word, 1)
 	if len(m) > 0 {
 		word = m[0][1] + replace + TrimLeft(ToLower(m[0][2]), replace)
 	}
 
-	r = regexp.MustCompile(`([A-Z]+)([A-Z]?[_a-z\d]+)|$`)
 	for {
-		m := r.FindAllStringSubmatch(word, 1)
+		m := firstCamelCaseStart.FindAllStringSubmatch(word, 1)
 		if len(m) > 0 && m[0][1] != "" {
 			w := strings.ToLower(m[0][1])
 			w = string(w[:len(w)-1]) + replace + string(w[len(w)-1])