Add East Asian charset mappings

Author: GtechGovind

go/sql/encoding.go

@@ -8,7 +8,10 @@ package sql
 import (
 	"golang.org/x/text/encoding"
 	"golang.org/x/text/encoding/charmap"
+	"golang.org/x/text/encoding/japanese"
+	"golang.org/x/text/encoding/korean"
 	"golang.org/x/text/encoding/simplifiedchinese"
+	"golang.org/x/text/encoding/traditionalchinese"
 )
 
 type charsetEncoding map[string]encoding.Encoding
@@ -20,4 +23,8 @@ func init() {
 	// Begin mappings
 	charsetEncodingMap["latin1"] = charmap.Windows1252
 	charsetEncodingMap["gbk"] = simplifiedchinese.GBK
+	charsetEncodingMap["big5"] = traditionalchinese.Big5
+	charsetEncodingMap["sjis"] = japanese.ShiftJIS
+	charsetEncodingMap["ujis"] = japanese.EUCJP
+	charsetEncodingMap["euckr"] = korean.EUCKR
 }

go/sql/encoding_test.go

@@ -0,0 +1,37 @@
+/*
+   Copyright 2016 GitHub Inc.
+	 See https://github.com/github/gh-ost/blob/master/LICENSE
+*/
+
+package sql
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestCharsetEncodingMap(t *testing.T) {
+	testCases := []struct {
+		name    string
+		charset string
+		encoded []byte
+		decoded string
+	}{
+		{name: "Big5", charset: "big5", encoded: []byte{0xa4, 0xa4, 0xa4, 0xe5}, decoded: "中文"},
+		{name: "Shift-JIS", charset: "sjis", encoded: []byte{0x93, 0xfa, 0x96, 0x7b}, decoded: "日本"},
+		{name: "EUC-JP", charset: "ujis", encoded: []byte{0xc6, 0xfc, 0xcb, 0xdc}, decoded: "日本"},
+		{name: "EUC-KR", charset: "euckr", encoded: []byte{0xc7, 0xd1, 0xb1, 0xb9}, decoded: "한국"},
+	}
+
+	for _, testCase := range testCases {
+		t.Run(testCase.name, func(t *testing.T) {
+			charset, ok := charsetEncodingMap[testCase.charset]
+			require.True(t, ok)
+
+			decoded, err := charset.NewDecoder().Bytes(testCase.encoded)
+			require.NoError(t, err)
+			require.Equal(t, testCase.decoded, string(decoded))
+		})
+	}
+}