1// Protocol Buffers for Go with Gadgets
2//
3// Copyright (c) 2013, The GoGo Authors. All rights reserved.
4// http://github.com/gogo/protobuf
5//
6// Redistribution and use in source and binary forms, with or without
7// modification, are permitted provided that the following conditions are
8// met:
9//
10//     * Redistributions of source code must retain the above copyright
11// notice, this list of conditions and the following disclaimer.
12//     * Redistributions in binary form must reproduce the above
13// copyright notice, this list of conditions and the following disclaimer
14// in the documentation and/or other materials provided with the
15// distribution.
16//
17// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
20// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
21// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
22// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
23// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28
29package io
30
31import (
32	"bufio"
33	"encoding/binary"
34	"errors"
35	"github.com/gogo/protobuf/proto"
36	"io"
37)
38
39var (
40	errSmallBuffer = errors.New("Buffer Too Small")
41	errLargeValue  = errors.New("Value is Larger than 64 bits")
42)
43
44func NewDelimitedWriter(w io.Writer) WriteCloser {
45	return &varintWriter{w, make([]byte, binary.MaxVarintLen64), nil}
46}
47
48type varintWriter struct {
49	w      io.Writer
50	lenBuf []byte
51	buffer []byte
52}
53
54func (this *varintWriter) WriteMsg(msg proto.Message) (err error) {
55	var data []byte
56	if m, ok := msg.(marshaler); ok {
57		n, ok := getSize(m)
58		if ok {
59			if n+binary.MaxVarintLen64 >= len(this.buffer) {
60				this.buffer = make([]byte, n+binary.MaxVarintLen64)
61			}
62			lenOff := binary.PutUvarint(this.buffer, uint64(n))
63			_, err = m.MarshalTo(this.buffer[lenOff:])
64			if err != nil {
65				return err
66			}
67			_, err = this.w.Write(this.buffer[:lenOff+n])
68			return err
69		}
70	}
71
72	// fallback
73	data, err = proto.Marshal(msg)
74	if err != nil {
75		return err
76	}
77	length := uint64(len(data))
78	n := binary.PutUvarint(this.lenBuf, length)
79	_, err = this.w.Write(this.lenBuf[:n])
80	if err != nil {
81		return err
82	}
83	_, err = this.w.Write(data)
84	return err
85}
86
87func (this *varintWriter) Close() error {
88	if closer, ok := this.w.(io.Closer); ok {
89		return closer.Close()
90	}
91	return nil
92}
93
94func NewDelimitedReader(r io.Reader, maxSize int) ReadCloser {
95	var closer io.Closer
96	if c, ok := r.(io.Closer); ok {
97		closer = c
98	}
99	return &varintReader{bufio.NewReader(r), nil, maxSize, closer}
100}
101
102type varintReader struct {
103	r       *bufio.Reader
104	buf     []byte
105	maxSize int
106	closer  io.Closer
107}
108
109func (this *varintReader) ReadMsg(msg proto.Message) error {
110	length64, err := binary.ReadUvarint(this.r)
111	if err != nil {
112		return err
113	}
114	length := int(length64)
115	if length < 0 || length > this.maxSize {
116		return io.ErrShortBuffer
117	}
118	if len(this.buf) < length {
119		this.buf = make([]byte, length)
120	}
121	buf := this.buf[:length]
122	if _, err := io.ReadFull(this.r, buf); err != nil {
123		return err
124	}
125	return proto.Unmarshal(buf, msg)
126}
127
128func (this *varintReader) Close() error {
129	if this.closer != nil {
130		return this.closer.Close()
131	}
132	return nil
133}
134