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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_SPDY_SPDY_FRAME_READER_H_ | |
6 #define NET_SPDY_SPDY_FRAME_READER_H_ | |
7 | |
8 #include "base/basictypes.h" | |
9 #include "base/strings/string_piece.h" | |
10 #include "net/base/net_export.h" | |
11 | |
12 namespace net { | |
13 | |
14 // Used for reading SPDY frames. Though there isn't really anything terribly | |
15 // SPDY-specific here, it's a helper class that's useful when doing SPDY | |
16 // framing. | |
17 // | |
18 // To use, simply construct a SpdyFramerReader using the underlying buffer that | |
19 // you'd like to read fields from, then call one of the Read*() methods to | |
20 // actually do some reading. | |
21 // | |
22 // This class keeps an internal iterator to keep track of what's already been | |
23 // read and each successive Read*() call automatically increments said iterator | |
24 // on success. On failure, internal state of the SpdyFrameReader should not be | |
25 // trusted and it is up to the caller to throw away the failed instance and | |
26 // handle the error as appropriate. None of the Read*() methods should ever be | |
27 // called after failure, as they will also fail immediately. | |
28 class NET_EXPORT_PRIVATE SpdyFrameReader { | |
29 public: | |
30 // Caller must provide an underlying buffer to work on. | |
31 SpdyFrameReader(const char* data, const size_t len); | |
32 | |
33 // Empty destructor. | |
34 ~SpdyFrameReader() {} | |
35 | |
36 // Reads an 8-bit unsigned integer into the given output parameter. | |
37 // Forwards the internal iterator on success. | |
38 // Returns true on success, false otherwise. | |
39 bool ReadUInt8(uint8* result); | |
40 | |
41 // Reads a 16-bit unsigned integer into the given output parameter. | |
42 // Forwards the internal iterator on success. | |
43 // Returns true on success, false otherwise. | |
44 bool ReadUInt16(uint16* result); | |
45 | |
46 // Reads a 32-bit unsigned integer into the given output parameter. | |
47 // Forwards the internal iterator on success. | |
48 // Returns true on success, false otherwise. | |
49 bool ReadUInt32(uint32* result); | |
50 | |
51 // Reads a 64-bit unsigned integer into the given output parameter. | |
52 // Forwards the internal iterator on success. | |
53 // Returns true on success, false otherwise. | |
54 bool ReadUInt64(uint64* result); | |
55 | |
56 // Reads a 31-bit unsigned integer into the given output parameter. This is | |
57 // equivalent to ReadUInt32() above except that the highest-order bit is | |
58 // discarded. | |
59 // Forwards the internal iterator (by 4B) on success. | |
60 // Returns true on success, false otherwise. | |
61 bool ReadUInt31(uint32* result); | |
62 | |
63 // Reads a 24-bit unsigned integer into the given output parameter. | |
64 // Forwards the internal iterator (by 3B) on success. | |
65 // Returns true on success, false otherwise. | |
66 bool ReadUInt24(uint32* result); | |
67 | |
68 // Reads a string prefixed with 16-bit length into the given output parameter. | |
69 // | |
70 // NOTE: Does not copy but rather references strings in the underlying buffer. | |
71 // This should be kept in mind when handling memory management! | |
72 // | |
73 // Forwards the internal iterator on success. | |
74 // Returns true on success, false otherwise. | |
75 bool ReadStringPiece16(base::StringPiece* result); | |
76 | |
77 // Reads a string prefixed with 32-bit length into the given output parameter. | |
78 // | |
79 // NOTE: Does not copy but rather references strings in the underlying buffer. | |
80 // This should be kept in mind when handling memory management! | |
81 // | |
82 // Forwards the internal iterator on success. | |
83 // Returns true on success, false otherwise. | |
84 bool ReadStringPiece32(base::StringPiece* result); | |
85 | |
86 // Reads a given number of bytes into the given buffer. The buffer | |
87 // must be of adequate size. | |
88 // Forwards the internal iterator on success. | |
89 // Returns true on success, false otherwise. | |
90 bool ReadBytes(void* result, size_t size); | |
91 | |
92 // Seeks a given number of bytes into the buffer from the current offset. | |
93 // Equivelant to an empty read. | |
94 // Forwards the internal iterator. | |
95 // Returns true on success, false otherwise. | |
96 bool Seek(size_t size); | |
97 | |
98 // Rewinds this reader to the beginning of the frame. | |
99 void Rewind() { ofs_ = 0; } | |
100 | |
101 // Returns true if the entirety of the underlying buffer has been read via | |
102 // Read*() calls. | |
103 bool IsDoneReading() const; | |
104 | |
105 // Returns the number of bytes that have been consumed by the reader so far. | |
106 size_t GetBytesConsumed() const { return ofs_; } | |
107 | |
108 private: | |
109 // Returns true if the underlying buffer has enough room to read the given | |
110 // amount of bytes. | |
111 bool CanRead(size_t bytes) const; | |
112 | |
113 // To be called when a read fails for any reason. | |
114 void OnFailure(); | |
115 | |
116 // The data buffer that we're reading from. | |
117 const char* data_; | |
118 | |
119 // The length of the data buffer that we're reading from. | |
120 const size_t len_; | |
121 | |
122 // The location of the next read from our data buffer. | |
123 size_t ofs_; | |
124 }; | |
125 | |
126 } // namespace net | |
127 | |
128 #endif // NET_SPDY_SPDY_FRAME_READER_H_ | |
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