fix some comments and small changes

Author: stephenfire

decode.go

@@ -26,7 +26,7 @@ func Unmarshal(buf []byte, v interface{}) error {
 	return Decode(NewValueReader(bytes.NewBuffer(buf), 0), v)
 }
 
-// Decode reads bytes from r unmarshal to v, if you want use same Reader to Decode multi
+// Decode reads bytes from r unmarshal to v, if you want to use same Reader to Decode multi
 // values, you should use encoding.ValueReader as io.Reader.
 func Decode(r io.Reader, v interface{}) error {
 	if v == nil {

types.go

@@ -346,7 +346,7 @@ func structFields(typ reflect.Type) (fieldNum int, fields []fieldName) {
 	}
 	for i := 0; i < typ.NumField(); i++ {
 		// exported field
-		if f := typ.Field(i); f.PkgPath == "" {
+		if f := typ.Field(i); f.IsExported() {
 			tagStr := f.Tag.Get("rtl")
 			ignored := false
 			for _, tag := range strings.Split(tagStr, ",") {

valuereader.go

@@ -155,7 +155,7 @@ func (r *bufValueReader) left() int {
 }
 
 // next read more bytes to buffer when buffer is empty,
-// and return whether has more bytes in buffer
+// and return if it has more bytes in buffer
 func (r *bufValueReader) next() bool {
 	if r.available > r.offset {
 		return true
@@ -361,10 +361,10 @@ func ReadMultiLengthBytesFromReader(vr ValueReader, length int, bytes []byte) ([
 }
 
 func NewValueReader(r io.Reader, bufferSize int) ValueReader {
-	len := int(MaxSliceSize)
+	l := MaxSliceSize
 	lenner, ok := r.(Lenner)
 	if ok {
-		len = lenner.Len()
+		l = lenner.Len()
 	}
 	if bufferSize > 0 {
 		return &bufValueReader{
@@ -373,14 +373,14 @@ func NewValueReader(r io.Reader, bufferSize int) ValueReader {
 			buffer:     make([]byte, bufferSize),
 			available:  0,
 			offset:     0,
-			readerSize: len,
+			readerSize: l,
 		}
 	} else {
 		return &noBufValueReader{
 			reader:     r,
 			eof:        false,
 			readCount:  0,
-			readerSize: len,
+			readerSize: l,
 		}
 	}
 }