Files
crockery/vendor/github.com/emersion/go-message/charset/charset.go
2018-06-28 01:09:56 +01:00

58 lines
1.9 KiB
Go

// Package charset provides functions to decode and encode charsets.
package charset
import (
"fmt"
"io"
"strings"
"golang.org/x/text/encoding"
"golang.org/x/text/encoding/charmap"
"golang.org/x/text/encoding/japanese"
"golang.org/x/text/encoding/simplifiedchinese"
"golang.org/x/text/encoding/traditionalchinese"
)
var charsets = map[string]encoding.Encoding{
"big5": traditionalchinese.Big5,
"euc-jp": japanese.EUCJP,
"gbk": simplifiedchinese.GBK,
"gb2312": simplifiedchinese.GBK, // as GBK is a superset of HZGB2312, so just use GBK
"gb18030": simplifiedchinese.GB18030, // GB18030 Use for parse QQ business mail message
"iso-2022-jp": japanese.ISO2022JP,
"iso-8859-1": charmap.ISO8859_1,
"iso-8859-2": charmap.ISO8859_2,
"iso-8859-3": charmap.ISO8859_3,
"iso-8859-4": charmap.ISO8859_4,
"iso-8859-9": charmap.ISO8859_9,
"iso-8859-10": charmap.ISO8859_10,
"iso-8859-13": charmap.ISO8859_13,
"iso-8859-14": charmap.ISO8859_14,
"iso-8859-15": charmap.ISO8859_15,
"iso-8859-16": charmap.ISO8859_16,
"koi8-r": charmap.KOI8R,
"shift_jis": japanese.ShiftJIS,
"windows-1250": charmap.Windows1250,
"windows-1251": charmap.Windows1251,
"windows-1252": charmap.Windows1252,
}
// Reader returns an io.Reader that converts the provided charset to UTF-8.
func Reader(charset string, input io.Reader) (io.Reader, error) {
charset = strings.ToLower(charset)
// "ascii" is not in the spec but is common
if charset == "utf-8" || charset == "us-ascii" || charset == "ascii" {
return input, nil
}
if enc, ok := charsets[charset]; ok {
return enc.NewDecoder().Reader(input), nil
}
return nil, fmt.Errorf("unhandled charset %q", charset)
}
// RegisterEncoding registers an encoding. This is intended to be called from
// the init function in packages that want to support additional charsets.
func RegisterEncoding(name string, enc encoding.Encoding) {
charsets[name] = enc
}