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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #ifndef NET_QUIC_QUIC_DATA_WRITER_H_ | |
6 #define NET_QUIC_QUIC_DATA_WRITER_H_ | |
7 | |
8 #include <string> | |
9 | |
10 #include "base/basictypes.h" | |
11 #include "base/logging.h" | |
12 #include "base/port.h" | |
13 #include "base/strings/string_piece.h" | |
14 #include "net/base/int128.h" | |
15 #include "net/base/net_export.h" | |
16 #include "net/quic/quic_protocol.h" | |
17 | |
18 namespace net { | |
19 | |
20 // This class provides facilities for packing QUIC data. | |
21 // | |
22 // The QuicDataWriter supports appending primitive values (int, string, etc) | |
23 // to a frame instance. The internal memory buffer is exposed as the "data" | |
24 // of the QuicDataWriter. | |
25 class NET_EXPORT_PRIVATE QuicDataWriter { | |
26 public: | |
27 // Creates a QuicDataWriter where |buffer| is not owned. | |
28 QuicDataWriter(size_t size, char* buffer); | |
29 | |
30 ~QuicDataWriter(); | |
31 | |
32 // Returns the size of the QuicDataWriter's data. | |
33 size_t length() const { return length_; } | |
34 | |
35 // Retrieves the buffer from the QuicDataWriter without changing ownership. | |
36 char* data(); | |
37 | |
38 // Methods for adding to the payload. These values are appended to the end | |
39 // of the QuicDataWriter payload. Note - binary integers are written in | |
40 // host byte order (little endian) not network byte order (big endian). | |
41 bool WriteUInt8(uint8 value); | |
42 bool WriteUInt16(uint16 value); | |
43 bool WriteUInt32(uint32 value); | |
44 bool WriteUInt48(uint64 value); | |
45 bool WriteUInt64(uint64 value); | |
46 // Write unsigned floating point corresponding to the value. Large values are | |
47 // clamped to the maximum representable (kUFloat16MaxValue). Values that can | |
48 // not be represented directly are rounded down. | |
49 bool WriteUFloat16(uint64 value); | |
50 bool WriteStringPiece16(base::StringPiece val); | |
51 bool WriteIOVector(const IOVector& data); | |
52 bool WriteBytes(const void* data, size_t data_len); | |
53 bool WriteRepeatedByte(uint8 byte, size_t count); | |
54 // Fills the remaining buffer with null characters. | |
55 void WritePadding(); | |
56 | |
57 // Methods for editing the payload at a specific offset, where the | |
58 // offset must be within the writer's capacity. | |
59 // Return true if there is enough space at that offset, false otherwise. | |
60 bool WriteUInt8ToOffset(uint8 value, size_t offset); | |
61 bool WriteUInt32ToOffset(uint32 value, size_t offset); | |
62 bool WriteUInt48ToOffset(uint64 value, size_t offset); | |
63 | |
64 size_t capacity() const { | |
65 return capacity_; | |
66 } | |
67 | |
68 private: | |
69 // Returns the location that the data should be written at, or nullptr if | |
70 // there is not enough room. Call EndWrite with the returned offset and the | |
71 // given length to pad out for the next write. | |
72 char* BeginWrite(size_t length); | |
73 | |
74 char* buffer_; | |
75 size_t capacity_; // Allocation size of payload (or -1 if buffer is const). | |
76 size_t length_; // Current length of the buffer. | |
77 | |
78 DISALLOW_COPY_AND_ASSIGN(QuicDataWriter); | |
79 }; | |
80 | |
81 } // namespace net | |
82 | |
83 #endif // NET_QUIC_QUIC_DATA_WRITER_H_ | |
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