diff options
Diffstat (limited to 'parser/reader.go')
| -rw-r--r-- | parser/reader.go | 29 |
1 files changed, 12 insertions, 17 deletions
diff --git a/parser/reader.go b/parser/reader.go index d77d1f5..6b077fc 100644 --- a/parser/reader.go +++ b/parser/reader.go @@ -2,6 +2,7 @@ package parser import ( "bufio" + "errors" "fmt" "io" "unicode" @@ -23,25 +24,19 @@ type reader struct { pos position } -func (reader *reader) peekRune() (r rune, err error) { - bytes := make([]byte, 0, 4) +// peakRune returns the next rune in the buffer without actually moving the +// parser forwards. +func (reader *reader) peekRune() (rune, error) { + bytes, _ := reader.r.Peek(4) + r, size := utf8.DecodeRune(bytes) - // Peeking the next rune is annoying. We want to get the next rune - // which could be the next 1–4 bytes. Normally we can just call - // reader.r.Peek(4) but that doesn’t work here as the last rune in a - // file could be a 1–3 byte rune, so we would fail with an EOF error. - for i := 4; i > 0; i-- { - if bytes, err = reader.r.Peek(i); err == io.EOF { - continue - } else if err != nil { - return - } else { - r, _ = utf8.DecodeRune(bytes) - return - } + switch { + case r == utf8.RuneError && size == 0: + return 0, io.EOF + case r == utf8.RuneError && size == 1: + return 0, errors.New("Tried to decode malformed UTF-8") } - - return 0, io.EOF + return r, nil } func (reader *reader) unreadRune() error { |