1/*
2 * libjingle
3 * Copyright 2004--2005, Google Inc.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 *  1. Redistributions of source code must retain the above copyright notice,
9 *     this list of conditions and the following disclaimer.
10 *  2. Redistributions in binary form must reproduce the above copyright notice,
11 *     this list of conditions and the following disclaimer in the documentation
12 *     and/or other materials provided with the distribution.
13 *  3. The name of the author may not be used to endorse or promote products
14 *     derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
17 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
18 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
19 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28#ifndef TALK_BASE_BYTEBUFFER_H_
29#define TALK_BASE_BYTEBUFFER_H_
30
31#include <string>
32
33#include "talk/base/basictypes.h"
34#include "talk/base/constructormagic.h"
35
36namespace talk_base {
37
38class ByteBuffer {
39 public:
40
41  enum ByteOrder {
42    ORDER_NETWORK = 0,  // Default, use network byte order (big endian).
43    ORDER_HOST,         // Use the native order of the host.
44  };
45
46  // |byte_order| defines order of bytes in the buffer.
47  ByteBuffer();
48  explicit ByteBuffer(ByteOrder byte_order);
49  ByteBuffer(const char* bytes, size_t len);
50  ByteBuffer(const char* bytes, size_t len, ByteOrder byte_order);
51
52  // Initializes buffer from a zero-terminated string.
53  explicit ByteBuffer(const char* bytes);
54
55  ~ByteBuffer();
56
57  const char* Data() const { return bytes_ + start_; }
58  size_t Length() const { return end_ - start_; }
59  size_t Capacity() const { return size_ - start_; }
60  ByteOrder Order() const { return byte_order_; }
61
62  // Read a next value from the buffer. Return false if there isn't
63  // enough data left for the specified type.
64  bool ReadUInt8(uint8* val);
65  bool ReadUInt16(uint16* val);
66  bool ReadUInt24(uint32* val);
67  bool ReadUInt32(uint32* val);
68  bool ReadUInt64(uint64* val);
69  bool ReadBytes(char* val, size_t len);
70
71  // Appends next |len| bytes from the buffer to |val|. Returns false
72  // if there is less than |len| bytes left.
73  bool ReadString(std::string* val, size_t len);
74
75  // Write value to the buffer. Resizes the buffer when it is
76  // neccessary.
77  void WriteUInt8(uint8 val);
78  void WriteUInt16(uint16 val);
79  void WriteUInt24(uint32 val);
80  void WriteUInt32(uint32 val);
81  void WriteUInt64(uint64 val);
82  void WriteString(const std::string& val);
83  void WriteBytes(const char* val, size_t len);
84
85  // Reserves the given number of bytes and returns a char* that can be written
86  // into. Useful for functions that require a char* buffer and not a
87  // ByteBuffer.
88  char* ReserveWriteBuffer(size_t len);
89
90  // Resize the buffer to the specified |size|. This invalidates any remembered
91  // seek positions.
92  void Resize(size_t size);
93
94  // Moves current position |size| bytes forward. Returns false if
95  // there is less than |size| bytes left in the buffer. Consume doesn't
96  // permanently remove data, so remembered read positions are still valid
97  // after this call.
98  bool Consume(size_t size);
99
100  // Clears the contents of the buffer. After this, Length() will be 0.
101  void Clear();
102
103  // Used with GetReadPosition/SetReadPosition.
104  class ReadPosition {
105    friend class ByteBuffer;
106    ReadPosition(size_t start, int version)
107        : start_(start), version_(version) { }
108    size_t start_;
109    int version_;
110  };
111
112  // Remembers the current read position for a future SetReadPosition. Any
113  // calls to Shift or Resize in the interim will invalidate the position.
114  ReadPosition GetReadPosition() const;
115
116  // If the given position is still valid, restores that read position.
117  bool SetReadPosition(const ReadPosition &position);
118
119 private:
120  void Construct(const char* bytes, size_t size, ByteOrder byte_order);
121
122  char* bytes_;
123  size_t size_;
124  size_t start_;
125  size_t end_;
126  int version_;
127  ByteOrder byte_order_;
128
129  // There are sensible ways to define these, but they aren't needed in our code
130  // base.
131  DISALLOW_COPY_AND_ASSIGN(ByteBuffer);
132};
133
134}  // namespace talk_base
135
136#endif  // TALK_BASE_BYTEBUFFER_H_
137