func From(encoding string, in []byte) (ret []rune, err error) {
var errCode C.UErrorCode
cEncoding := C.CString(encoding)
defer C.free(unsafe.Pointer(cEncoding))
conv := C.ucnv_open(cEncoding, &errCode)
if errCode != C.U_ZERO_ERROR {
err = errors.New("to_runes: error when open converter")
return
}
defer C.ucnv_close(conv)
ret = make([]rune, 0, len(in))
var target C.UChar32
header := (*reflect.SliceHeader)(unsafe.Pointer(&in))
source := (*C.char)(unsafe.Pointer(header.Data))
sourceLimit := (*C.char)(unsafe.Pointer(header.Data + uintptr(header.Len)))
for C.pointerLess(source, sourceLimit) == C.int(1) {
target = C.ucnv_getNextUChar(conv, &source, sourceLimit, &errCode)
if errCode != C.U_ZERO_ERROR {
err = errors.New("to_runes: error when decoding")
return
}
ret = append(ret, rune(target))
}
return
}
func ucnvOpen(encoding string) (*C.UConverter, error) {
cencoding := C.CString(encoding)
defer C.free(unsafe.Pointer(cencoding))
uErr := C.UErrorCode(C.U_ZERO_ERROR)
ucnv, err := C.ucnv_open(cencoding, &uErr)
if err != nil {
return nil, err
}
if err = uErrorToGoError(uErr); err != nil {
return nil, err
}
return ucnv, nil
}