WIP untested code to add GBK support

sources/VT100StringParser.h

@@ -32,6 +32,10 @@ NS_INLINE BOOL iscp949(unsigned char c) {
     return (c >= 0x81 && c <= 0xfe);
 }
+NS_INLINE BOOL isgbk(unsigned char c) {
+    return (c >= 0x81 && c <= 0xfe);
+}
+
 NS_INLINE BOOL isEUCCNEncoding(NSStringEncoding stringEncoding) {
     return (stringEncoding == (0x80000000 | kCFStringEncodingMacChineseSimp) ||
             stringEncoding == (0x80000000 | kCFStringEncodingDOSChineseSimplif) ||
@@ -68,6 +72,10 @@ NS_INLINE BOOL isCP949Encoding(NSStringEncoding stringEncoding) {
     return (stringEncoding == (0x80000000 | kCFStringEncodingDOSKorean));
 }
+NS_INLINE BOOL isGBKEncoding(NSStringEncoding stringEncoding) {
+    return (stringEncoding == (0x80000000 | kCFStringEncodingGBK_95));
+}
+
 NS_INLINE BOOL isAsciiString(unsigned char *code) {
     return *code >= 0x20 && *code <= 0x7f;
 }
@@ -87,6 +95,8 @@ NS_INLINE BOOL isString(unsigned char *code, NSStringEncoding encoding) {
         return iseuckr(*code);
     } else if (isCP949Encoding(encoding)) {
         return iscp949(*code);
+    } else if (isGBKEncoding(encoding)) {
+        return isgbk(*code);
     } else if (*code >= 0x20) {
         return YES;
     }

sources/VT100StringParser.m

@@ -234,6 +234,30 @@ static void DecodeCP949Bytes(unsigned char *datap,
     }
 }
+static void DecodeGBKBytes(unsigned char *datap,
+                           int datalen,
+                           int *rmlen,
+                           VT100Token *token) {
+    unsigned char *p = datap;
+    int len = datalen;
+
+    while (len > 0) {
+        if (iscp949(*p) && len > 1) {
+            p += 2;
+            len -= 2;
+        } else {
+            break;
+        }
+    }
+    if (len == datalen) {
+        *rmlen = 0;
+        token->type = VT100_WAIT;
+    } else {
+        *rmlen = datalen - len;
+        token->type = VT100_STRING;
+    }
+}
+
 static void DecodeOtherBytes(unsigned char *datap,
                              int datalen,
                              int *rmlen,
@@ -339,6 +363,8 @@ void ParseString(unsigned char *datap,
     } else if (isCP949Encoding(encoding)) {
         // korean
         DecodeCP949Bytes(datap, datalen, rmlen, result);
+    } else if (isGBKEncoding(encoding)) {
+        DecodeGBKBytes(datap, datalen, rmlen, result);
     } else {
         DecodeOtherBytes(datap, datalen, rmlen, result);
     }