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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 <stddef.h> | |
9 #include <stdint.h> | |
10 | |
11 #include "net/base/net_export.h" | |
12 #include "net/spdy/platform/api/spdy_string_piece.h" | |
13 | |
14 namespace net { | |
15 | |
16 // Used for reading SPDY frames. Though there isn't really anything terribly | |
17 // SPDY-specific here, it's a helper class that's useful when doing SPDY | |
18 // framing. | |
19 // | |
20 // To use, simply construct a SpdyFramerReader using the underlying buffer that | |
21 // you'd like to read fields from, then call one of the Read*() methods to | |
22 // actually do some reading. | |
23 // | |
24 // This class keeps an internal iterator to keep track of what's already been | |
25 // read and each successive Read*() call automatically increments said iterator | |
26 // on success. On failure, internal state of the SpdyFrameReader should not be | |
27 // trusted and it is up to the caller to throw away the failed instance and | |
28 // handle the error as appropriate. None of the Read*() methods should ever be | |
29 // called after failure, as they will also fail immediately. | |
30 class NET_EXPORT_PRIVATE SpdyFrameReader { | |
31 public: | |
32 // Caller must provide an underlying buffer to work on. | |
33 SpdyFrameReader(const char* data, const size_t len); | |
34 | |
35 // Empty destructor. | |
36 ~SpdyFrameReader() {} | |
37 | |
38 // Reads an 8-bit unsigned integer into the given output parameter. | |
39 // Forwards the internal iterator on success. | |
40 // Returns true on success, false otherwise. | |
41 bool ReadUInt8(uint8_t* result); | |
42 | |
43 // Reads a 16-bit unsigned integer into the given output parameter. | |
44 // Forwards the internal iterator on success. | |
45 // Returns true on success, false otherwise. | |
46 bool ReadUInt16(uint16_t* result); | |
47 | |
48 // Reads a 32-bit unsigned integer into the given output parameter. | |
49 // Forwards the internal iterator on success. | |
50 // Returns true on success, false otherwise. | |
51 bool ReadUInt32(uint32_t* result); | |
52 | |
53 // Reads a 64-bit unsigned integer into the given output parameter. | |
54 // Forwards the internal iterator on success. | |
55 // Returns true on success, false otherwise. | |
56 bool ReadUInt64(uint64_t* result); | |
57 | |
58 // Reads a 31-bit unsigned integer into the given output parameter. This is | |
59 // equivalent to ReadUInt32() above except that the highest-order bit is | |
60 // discarded. | |
61 // Forwards the internal iterator (by 4B) on success. | |
62 // Returns true on success, false otherwise. | |
63 bool ReadUInt31(uint32_t* result); | |
64 | |
65 // Reads a 24-bit unsigned integer into the given output parameter. | |
66 // Forwards the internal iterator (by 3B) on success. | |
67 // Returns true on success, false otherwise. | |
68 bool ReadUInt24(uint32_t* result); | |
69 | |
70 // Reads a string prefixed with 16-bit length into the given output parameter. | |
71 // | |
72 // NOTE: Does not copy but rather references strings in the underlying buffer. | |
73 // This should be kept in mind when handling memory management! | |
74 // | |
75 // Forwards the internal iterator on success. | |
76 // Returns true on success, false otherwise. | |
77 bool ReadStringPiece16(SpdyStringPiece* result); | |
78 | |
79 // Reads a string prefixed with 32-bit length into the given output parameter. | |
80 // | |
81 // NOTE: Does not copy but rather references strings in the underlying buffer. | |
82 // This should be kept in mind when handling memory management! | |
83 // | |
84 // Forwards the internal iterator on success. | |
85 // Returns true on success, false otherwise. | |
86 bool ReadStringPiece32(SpdyStringPiece* result); | |
87 | |
88 // Reads a given number of bytes into the given buffer. The buffer | |
89 // must be of adequate size. | |
90 // Forwards the internal iterator on success. | |
91 // Returns true on success, false otherwise. | |
92 bool ReadBytes(void* result, size_t size); | |
93 | |
94 // Seeks a given number of bytes into the buffer from the current offset. | |
95 // Equivelant to an empty read. | |
96 // Forwards the internal iterator. | |
97 // Returns true on success, false otherwise. | |
98 bool Seek(size_t size); | |
99 | |
100 // Rewinds this reader to the beginning of the frame. | |
101 void Rewind() { ofs_ = 0; } | |
102 | |
103 // Returns true if the entirety of the underlying buffer has been read via | |
104 // Read*() calls. | |
105 bool IsDoneReading() const; | |
106 | |
107 // Returns the number of bytes that have been consumed by the reader so far. | |
108 size_t GetBytesConsumed() const { return ofs_; } | |
109 | |
110 private: | |
111 // Returns true if the underlying buffer has enough room to read the given | |
112 // amount of bytes. | |
113 bool CanRead(size_t bytes) const; | |
114 | |
115 // To be called when a read fails for any reason. | |
116 void OnFailure(); | |
117 | |
118 // The data buffer that we're reading from. | |
119 const char* data_; | |
120 | |
121 // The length of the data buffer that we're reading from. | |
122 const size_t len_; | |
123 | |
124 // The location of the next read from our data buffer. | |
125 size_t ofs_; | |
126 }; | |
127 | |
128 } // namespace net | |
129 | |
130 #endif // NET_SPDY_SPDY_FRAME_READER_H_ | |
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