// Lookup returns the encoding with the specified label, and its canonical
// name. It returns nil and the empty string if label is not one of the
// standard encodings for HTML. Matching is case-insensitive and ignores
// leading and trailing whitespace. Encoders will use HTML escape sequences for
// runes that are not supported by the character set.
func Lookup(label string) (e encoding.Encoding, name string) {
e, err := htmlindex.Get(label)
if err != nil {
return nil, ""
}
name, _ = htmlindex.Name(e)
return &htmlEncoding{e}, name
}
// Find returns
func findEncoding(name string) (encoding.Encoding, bool) {
if name == "" {
return Plain, true
}
d, ok := encodings[strings.ToLower(name)]
if ok {
return d, ok
}
codec, err := htmlindex.Get(name)
return codec, err == nil
}
// FindEncoding searches for an EncodingFactoryby name.
func FindEncoding(name string) (EncodingFactory, bool) {
if name == "" {
return Plain, true
}
d, ok := encodings[strings.ToLower(name)]
if ok {
return d, ok
}
codec, err := htmlindex.Get(name)
if err != nil {
return nil, false
}
return enc(codec), true
}
// ToUTF8 converts the given encoded text to a UTF-8 string.
func ToUTF8(encodingName string, b []byte) (string, error) {
if encodingName == "" {
return transformBytes(encoding.Replacement.NewEncoder(), b)
}
e, err := htmlindex.Get(encodingName)
if err != nil {
return "", ErrUnsupportedEncoding
}
var t transform.Transformer
if e == encoding.Replacement {
t = encoding.Replacement.NewEncoder()
} else {
t = e.NewDecoder()
}
return transformBytes(t, b)
}
// read reader content to string, using charset specified
func readToStringWithCharset(reader io.Reader, charset string) (string, error) {
charset = strings.ToUpper(charset)
var data []byte
var err error
if charset == "UTF-8" || charset == "UTF8" {
data, err = ioutil.ReadAll(reader)
} else {
if charset == "GBK" || charset == "GB2312" {
charset = "GB18030"
}
var encoder encoding.Encoding
encoder, err = htmlindex.Get(charset)
if err != nil {
return "", err
}
data, err = ioutil.ReadAll(transform.NewReader(reader, encoder.NewDecoder()))
}
if err != nil {
return "", err
}
return string(data), err
}