add EOF() method to proto.Buffer

proto/decode.go

@@ -464,7 +464,7 @@ func (o *Buffer) unmarshalType(st reflect.Type, prop *StructProperties, is_group
 	required, reqFields := prop.reqCount, uint64(0)
 
 	var err error
-	for err == nil && o.index < len(o.buf) {
+	for err == nil && !o.EOF() {
 		oi := o.index
 		var u uint64
 		u, err = o.DecodeVarint()

proto/lib.go

@@ -344,6 +344,23 @@ func (p *Buffer) SetBuf(s []byte) {
 // Bytes returns the contents of the Buffer.
 func (p *Buffer) Bytes() []byte { return p.buf }
 
+// EOF returns true when there is no more data to read and decode.
+func (p *Buffer) EOF() bool {
+	return p.index >= len(p.buf)
+}
+
+// ReaderIndex returns the current offset in Buffer for reading. Calls to the
+// various Decode* methods will read and decode data starting at this index in
+// the Buffer's underlying byte slice.
+func (p *Buffer) ReaderIndex() int { return p.index }
+
+// SetReaderIndex changes the current offset in Buffer for reading to the
+// given value. Subsequent calls to Decode* methods will read and decode data
+// starting at this index in the Buffer's underlying byte slice.
+func (p *Buffer) SetReaderIndex(index int) {
+	p.index = index
+}
+
 /*
  * Helper routines for simplifying the creation of optional fields of basic type.
  */