1 // Protocol Buffers for Go with Gadgets 2 // 3 // Copyright (c) 2015, 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 29 package codec 30 31 import ( 32 "github.com/gogo/protobuf/proto" 33 ) 34 35 type Codec interface { 36 Marshal(v interface{}) ([]byte, error) 37 Unmarshal(data []byte, v interface{}) error 38 String() string 39 } 40 41 type marshaler interface { 42 MarshalTo(data []byte) (n int, err error) 43 } 44 45 func getSize(v interface{}) (int, bool) { 46 if sz, ok := v.(interface { 47 Size() (n int) 48 }); ok { 49 return sz.Size(), true 50 } else if sz, ok := v.(interface { 51 ProtoSize() (n int) 52 }); ok { 53 return sz.ProtoSize(), true 54 } else { 55 return 0, false 56 } 57 } 58 59 type codec struct { 60 buf []byte 61 } 62 63 func (this *codec) String() string { 64 return "proto" 65 } 66 67 func New(size int) Codec { 68 return &codec{make([]byte, size)} 69 } 70 71 func (this *codec) Marshal(v interface{}) ([]byte, error) { 72 if m, ok := v.(marshaler); ok { 73 n, ok := getSize(v) 74 if !ok { 75 return proto.Marshal(v.(proto.Message)) 76 } 77 if n > len(this.buf) { 78 this.buf = make([]byte, n) 79 } 80 _, err := m.MarshalTo(this.buf) 81 if err != nil { 82 return nil, err 83 } 84 return this.buf[:n], nil 85 } 86 return proto.Marshal(v.(proto.Message)) 87 } 88 89 func (this *codec) Unmarshal(data []byte, v interface{}) error { 90 return proto.Unmarshal(data, v.(proto.Message)) 91 } 92