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_READER_H_ 6 #define NET_QUIC_QUIC_DATA_READER_H_ 7 8 #include "base/basictypes.h" 9 #include "base/strings/string_piece.h" 10 #include "net/base/int128.h" 11 #include "net/base/net_export.h" 12 13 namespace net { 14 15 // Used for reading QUIC data. Though there isn't really anything terribly 16 // QUIC-specific here, it's a helper class that's useful when doing QUIC 17 // framing. 18 // 19 // To use, simply construct a QuicDataReader using the underlying buffer that 20 // you'd like to read fields from, then call one of the Read*() methods to 21 // actually do some reading. 22 // 23 // This class keeps an internal iterator to keep track of what's already been 24 // read and each successive Read*() call automatically increments said iterator 25 // on success. On failure, internal state of the QuicDataReader should not be 26 // trusted and it is up to the caller to throw away the failed instance and 27 // handle the error as appropriate. None of the Read*() methods should ever be 28 // called after failure, as they will also fail immediately. 29 class NET_EXPORT_PRIVATE QuicDataReader { 30 public: 31 // Caller must provide an underlying buffer to work on. 32 QuicDataReader(const char* data, const size_t len); 33 34 // Empty destructor. 35 ~QuicDataReader() {} 36 37 // Reads a 16-bit unsigned integer into the given output parameter. 38 // Forwards the internal iterator on success. 39 // Returns true on success, false otherwise. 40 bool ReadUInt16(uint16* result); 41 42 // Reads a 32-bit unsigned integer into the given output parameter. 43 // Forwards the internal iterator on success. 44 // Returns true on success, false otherwise. 45 bool ReadUInt32(uint32* result); 46 47 // Reads a 48-bit unsigned integer into the given output parameter. 48 // Forwards the internal iterator on success. 49 // Returns true on success, false otherwise. 50 bool ReadUInt48(uint64* result); 51 52 // Reads a 64-bit unsigned integer into the given output parameter. 53 // Forwards the internal iterator on success. 54 // Returns true on success, false otherwise. 55 bool ReadUInt64(uint64* result); 56 57 // Reads a 128-bit unsigned integer into the given output parameter. 58 // Forwards the internal iterator on success. 59 // Returns true on success, false otherwise. 60 bool ReadUInt128(uint128* result); 61 62 // Reads a 16-bit unsigned float into the given output parameter. 63 // Forwards the internal iterator on success. 64 // Returns true on success, false otherwise. 65 bool ReadUFloat16(uint64* result); 66 67 // Reads a string prefixed with 16-bit length into the given output parameter. 68 // 69 // NOTE: Does not copy but rather references strings in the underlying buffer. 70 // This should be kept in mind when handling memory management! 71 // 72 // Forwards the internal iterator on success. 73 // Returns true on success, false otherwise. 74 bool ReadStringPiece16(base::StringPiece* result); 75 76 // Reads a given number of bytes into the given buffer. The buffer 77 // must be of adequate size. 78 // Forwards the internal iterator on success. 79 // Returns true on success, false otherwise. 80 bool ReadStringPiece(base::StringPiece* result, size_t len); 81 82 // Returns the remaining payload as a StringPiece. 83 // 84 // NOTE: Does not copy but rather references strings in the underlying buffer. 85 // This should be kept in mind when handling memory management! 86 // 87 // Forwards the internal iterator. 88 base::StringPiece ReadRemainingPayload(); 89 90 // Returns the remaining payload as a StringPiece. 91 // 92 // NOTE: Does not copy but rather references strings in the underlying buffer. 93 // This should be kept in mind when handling memory management! 94 // 95 // DOES NOT forward the internal iterator. 96 base::StringPiece PeekRemainingPayload(); 97 98 // Reads a given number of bytes into the given buffer. The buffer 99 // must be of adequate size. 100 // Forwards the internal iterator on success. 101 // Returns true on success, false otherwise. 102 bool ReadBytes(void* result, size_t size); 103 104 // Returns true if the entirety of the underlying buffer has been read via 105 // Read*() calls. 106 bool IsDoneReading() const; 107 108 // Returns the number of bytes remaining to be read. 109 size_t BytesRemaining() const; 110 111 private: 112 // Returns true if the underlying buffer has enough room to read the given 113 // amount of bytes. 114 bool CanRead(size_t bytes) const; 115 116 // To be called when a read fails for any reason. 117 void OnFailure(); 118 119 // The data buffer that we're reading from. 120 const char* data_; 121 122 // The length of the data buffer that we're reading from. 123 const size_t len_; 124 125 // The location of the next read from our data buffer. 126 size_t pos_; 127 }; 128 129 } // namespace net 130 131 #endif // NET_QUIC_QUIC_DATA_READER_H_ 132
