From 01f093e10e7779da59545877b951c2dd98144c25 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E9=99=88=E5=BF=97=E5=90=8C?= <bitcoin2077@outlook.com>
Date: Tue, 5 Dec 2023 20:29:32 +0800
Subject: [PATCH] Base64fixed (#407)

* fixed bug

* add comments

---------

Co-authored-by: Jimmy <jinghui@wayne.edu>
---
 src/neoxp/Extensions/Extensions.cs | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/neoxp/Extensions/Extensions.cs b/src/neoxp/Extensions/Extensions.cs
index be0cbd69..89fb083f 100644
--- a/src/neoxp/Extensions/Extensions.cs
+++ b/src/neoxp/Extensions/Extensions.cs
@@ -20,8 +20,10 @@
 using Neo.Wallets;
 using NeoExpress.Models;
 using System.Diagnostics.CodeAnalysis;
+using System.Globalization;
 using System.Numerics;
 using System.Text;
+using System.Text.RegularExpressions;
 
 namespace NeoExpress
 {
@@ -108,6 +110,7 @@ public static bool IsValidHexString(this string text)
         public static bool TryGetBytesFromBase64String(this string text, out Span<byte> bytes)
         {
             bytes = null;
+            text = Base64Fixed(text);
             Span<byte> buffer = new byte[text.Length * 3 / 4];
             if (Convert.TryFromBase64String(text, buffer, out var bytesWritten))
             {
@@ -117,7 +120,24 @@ public static bool TryGetBytesFromBase64String(this string text, out Span<byte>
             return false;
         }
 
-
+        /// <summary>
+        /// Convert Unicode Characters to AscII Characters by Regular Expressions.
+        /// </summary>
+        /// <param name="str">Base64 string with Unicode escaping. e.g. DCECbzTesnBofh/Xng1SofChKkBC7jhVmLxCN1vk\u002B49xa2pBVuezJw==</param>
+        /// <returns>Base64 strings without Unicode escaping. e.g. DCECbzTesnBofh/Xng1SofChKkBC7jhVmLxCN1vk+49xa2pBVuezJw==</returns>
+        public static string Base64Fixed(string str)
+        {
+            //Unicode e.g. \u002B
+            MatchCollection mc = Regex.Matches(str, @"\\u([\w]{2})([\w]{2})", RegexOptions.Compiled | RegexOptions.IgnoreCase);
+            byte[] bts = new byte[2];
+            foreach (Match m in mc)
+            {
+                bts[0] = (byte)int.Parse(m.Groups[2].Value, NumberStyles.HexNumber);
+                bts[1] = (byte)int.Parse(m.Groups[1].Value, NumberStyles.HexNumber);
+                str = str.Replace(m.ToString(), Encoding.Unicode.GetString(bts));
+            }
+            return str;
+        }
 
 
         public static string EscapeString(this string text)