From f64f13c2a75092b3b1dc2fc85a0860b61888c944 Mon Sep 17 00:00:00 2001
From: Levin Li <lilinfeng303@outlook.com>
Date: Thu, 30 Dec 2021 20:47:44 +0800
Subject: [PATCH] Implement NSGB_18030_2000StringEncoding,
 NSGB_2312_80StringEncoding, NSGBK_95StringEncoding

---
 Source/Additions/GSMime.m  |  4 ++++
 Source/Additions/Unicode.m | 12 +++++++++++-
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/Source/Additions/GSMime.m b/Source/Additions/GSMime.m
index a376de996..ae3543928 100644
--- a/Source/Additions/GSMime.m
+++ b/Source/Additions/GSMime.m
@@ -5421,6 +5421,8 @@ appendString(NSMutableData *m, NSUInteger offset, NSUInteger fold,
       (void*)NSDOSChineseSimplifStringEncoding);
     NSMapInsert(charsets, (void*)@"cp936",
       (void*)NSDOSChineseSimplifStringEncoding);
+    NSMapInsert(charsets, (void*)@"gbk",
+      (void*)NSDOSChineseSimplifStringEncoding);
     NSMapInsert(charsets, (void*)@"ibm949",
       (void*)NSDOSKoreanStringEncoding);
     NSMapInsert(charsets, (void*)@"cp949",
@@ -5659,6 +5661,8 @@ appendString(NSMutableData *m, NSUInteger offset, NSUInteger fold,
       (void*)@"windows-1258");
     NSMapInsert(encodings, (void*)NSWindowsKoreanJohabStringEncoding,
       (void*)@"windows-1361");
+    NSMapInsert(encodings, (void*)NSGB_18030_2000StringEncoding,
+      (void*)@"gb18030");
 #endif
 	}
       if (headerClass == 0)
diff --git a/Source/Additions/Unicode.m b/Source/Additions/Unicode.m
index c1367a970..dedd7a99a 100644
--- a/Source/Additions/Unicode.m
+++ b/Source/Additions/Unicode.m
@@ -314,6 +314,13 @@ static struct _strenc_ str_encoding_table[] = {
   {NSWindowsKoreanJohabStringEncoding,
     "NSWindowsKoreanJohabStringEncoding","CP1361",0,0,0},
 
+  {NSGB_2312_80StringEncoding,
+    "NSGB_2312_80StringEncoding","EUC-CN",0,0,0}, // Same as NSChineseEUCStringEncoding
+  {NSGBK_95StringEncoding,
+    "NSGBK_95StringEncoding","CP936",0,0,0}, // Same as NSDOSChineseSimplifStringEncoding
+  {NSGB_18030_2000StringEncoding,
+    "NSGB_18030_2000StringEncoding","GB18030",0,0,0},
+
 /* Now Apple encodings which have high numeric values.
  */
   {NSUTF16BigEndianStringEncoding,
@@ -2941,7 +2948,8 @@ GSPrivateCStringEncoding(const char *encoding)
         || strcmp(encoding, "IBM-932") == 0)
         enc = NSDOSJapaneseStringEncoding;
       else if (strcmp(encoding, "CP936") == 0
-        || strcmp(encoding, "IBM-936") == 0)
+        || strcmp(encoding, "IBM-936") == 0
+        || strcmp(encoding, "GBK") == 0)
         enc = NSDOSChineseSimplifStringEncoding;
       else if (strcmp(encoding, "CP949") == 0
         || strcmp(encoding, "IBM-949") == 0)
@@ -2964,6 +2972,8 @@ GSPrivateCStringEncoding(const char *encoding)
       else if (strcmp(encoding, "CP1361") == 0
         || strcmp(encoding, "WINDOWS-1361") == 0)
         enc = NSWindowsKoreanJohabStringEncoding;
+      else if (strcmp(encoding, "GB18030") == 0)
+        enc = NSGB_18030_2000StringEncoding;
     }
 
   if (enc == GSUndefinedEncoding)