1 files changed, 14 insertions, 20 deletions
diff --git a/decode_scan.go b/decode_scan.go
index 249975d..387fcea 100644
--- a/decode_scan.go
+++ b/decode_scan.go
@@ -35,34 +35,30 @@ type runeTypeScannerImpl struct {
 
 	inner io.RuneScanner // initialized by constructor
 
-	initialized bool
-
 	parser internal.Parser // initialized by constructor
 	offset int64
 
-	repeat  bool
-	stuck   bool
-	rRune   rune
-	rRuneOK bool
-	rSize   int
-	rType   internal.RuneType
-	rErr    error
+	initialized bool
+	repeat      bool
+
+	rRune rune
+	rSize int
+	rType internal.RuneType
+	rErr  error
 }
 
 var _ runeTypeScanner = (*runeTypeScannerImpl)(nil)
 
 func (sc *runeTypeScannerImpl) Reset() {
 	sc.parser.Reset()
-	unread := sc.stuck && sc.rType == internal.RuneTypeEOF && sc.rRuneOK
-	sc.stuck = false
-	sc.repeat = false
-	if unread {
+	if sc.repeat || (sc.rType == internal.RuneTypeEOF && sc.rSize > 0) {
+		sc.repeat = false
 		// re-figure the rType and rErr
 		var err error
 		sc.rType, err = sc.parser.HandleRune(sc.rRune)
 		if err != nil {
 			sc.rErr = &DecodeSyntaxError{
-				Offset: sc.offset,
+				Offset: sc.offset - int64(sc.rSize),
 				Err:    err,
 			}
 		} else {
@@ -75,21 +71,21 @@ func (sc *runeTypeScannerImpl) Reset() {
 
 func (sc *runeTypeScannerImpl) ReadRuneType() (rune, int, internal.RuneType, error) {
 	switch {
-	case sc.stuck:
+	case sc.initialized && (sc.rType == internal.RuneTypeError || sc.rType == internal.RuneTypeEOF):
 		// do nothing
 	case sc.repeat:
 		_, _, _ = sc.inner.ReadRune()
 	default:
+		sc.initialized = true
 		var err error
 		sc.rRune, sc.rSize, err = sc.inner.ReadRune()
 		sc.offset += int64(sc.rSize)
-		sc.rRuneOK = err == nil
 		switch err {
 		case nil:
 			sc.rType, err = sc.parser.HandleRune(sc.rRune)
 			if err != nil {
 				sc.rErr = &DecodeSyntaxError{
-					Offset: sc.offset,
+					Offset: sc.offset - int64(sc.rSize),
 					Err:    err,
 				}
 			} else {
@@ -113,9 +109,7 @@ func (sc *runeTypeScannerImpl) ReadRuneType() (rune, int, internal.RuneType, err
 			}
 		}
 	}
-	sc.initialized = true
 	sc.repeat = false
-	sc.stuck = sc.rType == internal.RuneTypeEOF || sc.rType == internal.RuneTypeError
 	return sc.rRune, sc.rSize, sc.rType, sc.rErr
 }
 
@@ -137,7 +131,7 @@ func (sc *runeTypeScannerImpl) ReadRune() (rune, int, error) {
 // unread, or if that call returned a rune with size 0, then
 // ErrInvalidUnreadRune is returned.  Otherwise, nil is returned.
 func (sc *runeTypeScannerImpl) UnreadRune() error {
-	if !sc.initialized || sc.repeat || sc.rSize == 0 {
+	if sc.repeat || sc.rSize == 0 {
 		return ErrInvalidUnreadRune
 	}
 	sc.repeat = true