package charset
import (
"bytes"
"fmt"
"unicode/utf8"
)
func init() {
registerClass("ascii", fromASCII, toASCII)
}
const errorByte = '?'
type translateFromASCII bool
type codePointError struct {
i int
cp rune
charset string
}
func (e *codePointError) Error() string {
return fmt.Sprintf("Parse error at index %n: Code point %n is undefined in %s", e.i, e.cp, e.charset)
}
func (strict translateFromASCII) Translate(data []byte, eof bool) (int, []byte, error) {
buf := bytes.NewBuffer(make([]byte, 0, len(data)))
for i, c := range data {
if c > 0 && c < 128 {
buf.WriteByte(c)
if c < 32 && c != 10 && c != 13 && c != 9 {
// badly formed
}
} else {
if strict {
return 0, nil, &codePointError{i, rune(c), "US-ASCII"}
}
buf.WriteRune(utf8.RuneError)
}
}
return len(data), buf.Bytes(), nil
}
type translateToASCII bool
func (strict translateToASCII) Translate(data []byte, eof bool) (int, []byte, error) {
buf := bytes.NewBuffer(make([]byte, 0, len(data)))
for _, c := range data {
if c > 0 && c < 128 {
buf.WriteByte(c)
} else {
buf.WriteByte(errorByte)
}
}
return len(data), buf.Bytes(), nil
}
func fromASCII(arg string) (Translator, error) {
return new(translateFromASCII), nil
}
func toASCII(arg string) (Translator, error) {
return new(translateToASCII), nil
}