Bug#30315 Character sets: insertion of euckr code value 0xa141 fails

Problem: some valid euc-kr characters were rejected because
condition checking multi-byte tail didn't allow 
multi-byte characters having the second byte in the ranges
[0x41..0x5A]  and [0x61..0x7A].

Fix: allow these byte ranges for mb tails

mysql-test/r/ctype_euckr.result

@@ -165,3 +165,44 @@ hex(a)
 A2E6
 FEF7
 DROP TABLE t1;
+create table t1 (s1 varchar(5) character set euckr);
+insert into t1 values (0xA141);
+insert into t1 values (0xA15A);
+insert into t1 values (0xA161);
+insert into t1 values (0xA17A);
+insert into t1 values (0xA181);
+insert into t1 values (0xA1FE);
+insert into t1 values (0xA140);
+Warnings:
+Warning	1366	Incorrect string value: '\xA1@' for column 's1' at row 1
+insert into t1 values (0xA15B);
+Warnings:
+Warning	1366	Incorrect string value: '\xA1[' for column 's1' at row 1
+insert into t1 values (0xA160);
+Warnings:
+Warning	1366	Incorrect string value: '\xA1`' for column 's1' at row 1
+insert into t1 values (0xA17B);
+Warnings:
+Warning	1366	Incorrect string value: '\xA1{' for column 's1' at row 1
+insert into t1 values (0xA180);
+Warnings:
+Warning	1366	Incorrect string value: '\xA1\x80' for column 's1' at row 1
+insert into t1 values (0xA1FF);
+Warnings:
+Warning	1366	Incorrect string value: '\xA1\xFF' for column 's1' at row 1
+select hex(s1), hex(convert(s1 using utf8)) from t1 order by binary s1;
+hex(s1)	hex(convert(s1 using utf8))
+	
+	
+	
+	
+	
+	
+A141	ECA2A5
+A15A	ECA381
+A161	ECA382
+A17A	ECA3A5
+A181	ECA3A6
+A1FE	EFBFA2
+drop table t1;
+End of 5.0 tests

mysql-test/t/ctype_euckr.test

@@ -31,3 +31,26 @@ SELECT hex(a) FROM t1 ORDER BY a;
 DROP TABLE t1;
 
 # End of 4.1 tests
+
+#
+#Bug #30315 Character sets: insertion of euckr code value 0xa141 fails
+#
+create table t1 (s1 varchar(5) character set euckr);
+# Insert some valid characters
+insert into t1 values (0xA141);
+insert into t1 values (0xA15A);
+insert into t1 values (0xA161);
+insert into t1 values (0xA17A);
+insert into t1 values (0xA181);
+insert into t1 values (0xA1FE);
+# Insert some invalid characters
+insert into t1 values (0xA140);
+insert into t1 values (0xA15B);
+insert into t1 values (0xA160);
+insert into t1 values (0xA17B);
+insert into t1 values (0xA180);
+insert into t1 values (0xA1FF);
+select hex(s1), hex(convert(s1 using utf8)) from t1 order by binary s1;
+drop table t1;
+
+--echo End of 5.0 tests

strings/ctype-euc_kr.c

@@ -179,20 +179,39 @@ static uchar NEAR sort_order_euc_kr[]=
 
 /* Support for Korean(EUC_KR) characters, by powerm90@tinc.co.kr and mrpark@tinc.co.kr */
 
-#define iseuc_kr(c)     ((0xa1<=(uchar)(c) && (uchar)(c)<=0xfe))
+/*
+ Unicode mapping is done according to:
+ ftp://ftp.unicode.org/Public/MAPPINGS/OBSOLETE/EASTASIA/KSC/KSC5601.TXT
+ 
+ Valid multi-byte characters:
+ 
+   [A1..FE][41..5A,61..7A,81..FE]
+ 
+ Note, 0x5C is not a valid MB tail,
+ so escape_with_backslash_is_dangerous is not set.
+*/
+
+#define iseuc_kr_head(c)     ((0xa1<=(uchar)(c) && (uchar)(c)<=0xfe))
+
+#define iseuc_kr_tail1(c)    ((uchar) (c) >= 0x41 && (uchar) (c) <= 0x5A)
+#define iseuc_kr_tail2(c)    ((uchar) (c) >= 0x61 && (uchar) (c) <= 0x7A)
+#define iseuc_kr_tail3(c)    ((uchar) (c) >= 0x81 && (uchar) (c) <= 0xFE)
 
+#define iseuc_kr_tail(c)     (iseuc_kr_tail1(c) || \
+                              iseuc_kr_tail2(c) || \
+                              iseuc_kr_tail3(c))
 
 static int ismbchar_euc_kr(CHARSET_INFO *cs __attribute__((unused)),
 		    const char* p, const char *e)
 {
   return ((*(uchar*)(p)<0x80)? 0:\
-          iseuc_kr(*(p)) && (e)-(p)>1 && iseuc_kr(*((p)+1))? 2:\
+          iseuc_kr_head(*(p)) && (e)-(p)>1 && iseuc_kr_tail(*((p)+1))? 2:\
           0);
 }
 
 static int mbcharlen_euc_kr(CHARSET_INFO *cs __attribute__((unused)),uint c)
 {
-  return (iseuc_kr(c) ? 2 : 1);
+  return (iseuc_kr_head(c) ? 2 : 1);
 }
 
 
@@ -8653,7 +8672,7 @@ my_well_formed_len_euckr(CHARSET_INFO *cs __attribute__((unused)),
       /* Single byte ascii character */
       b++;
     }
-    else  if (b < emb && iseuc_kr(*b) && iseuc_kr(b[1]))
+    else  if (b < emb && iseuc_kr_head(*b) && iseuc_kr_tail(b[1]))
     {
       /* Double byte character */
       b+= 2;