1 // Copyright 2014 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_HPACK_INPUT_STREAM_H_ 6 #define NET_SPDY_HPACK_INPUT_STREAM_H_ 7 8 #include <string> 9 10 #include "base/basictypes.h" 11 #include "base/macros.h" 12 #include "base/strings/string_piece.h" 13 #include "net/base/net_export.h" 14 #include "net/spdy/hpack_constants.h" 15 #include "net/spdy/hpack_huffman_table.h" 16 17 // All section references below are to 18 // http://tools.ietf.org/html/draft-ietf-httpbis-header-compression-08 19 20 namespace net { 21 22 // An HpackInputStream handles all the low-level details of decoding 23 // header fields. 24 class NET_EXPORT_PRIVATE HpackInputStream { 25 public: 26 // |max_string_literal_size| is the largest that any one string 27 // literal (header name or header value) can be. 28 HpackInputStream(uint32 max_string_literal_size, base::StringPiece buffer); 29 ~HpackInputStream(); 30 31 // Returns whether or not there is more data to process. 32 bool HasMoreData() const; 33 34 // If the next bits of input match |prefix|, consumes them and returns true. 35 // Otherwise, consumes nothing and returns false. 36 bool MatchPrefixAndConsume(HpackPrefix prefix); 37 38 // The Decode* functions return true and fill in their arguments if 39 // decoding was successful, or false if an error was encountered. 40 41 bool DecodeNextUint32(uint32* I); 42 bool DecodeNextIdentityString(base::StringPiece* str); 43 bool DecodeNextHuffmanString(const HpackHuffmanTable& table, 44 std::string* str); 45 46 // Stores input bits into the most-significant, unfilled bits of |out|. 47 // |peeked_count| is the number of filled bits in |out| which have been 48 // previously peeked. PeekBits() will fill some number of remaining bits, 49 // returning the new total number via |peeked_count|. Returns true if one 50 // or more additional bits could be peeked, and false otherwise. 51 bool PeekBits(size_t* peeked_count, uint32* out); 52 53 // Consumes |count| bits of input. Generally paired with PeekBits(). 54 void ConsumeBits(size_t count); 55 56 // If not currently on a byte boundary, consumes and discards 57 // remaining bits in the current byte. 58 void ConsumeByteRemainder(); 59 60 // Accessors for testing. 61 SetBitOffsetForTest(size_t bit_offset)62 void SetBitOffsetForTest(size_t bit_offset) { 63 bit_offset_ = bit_offset; 64 } 65 66 private: 67 const uint32 max_string_literal_size_; 68 base::StringPiece buffer_; 69 size_t bit_offset_; 70 71 bool PeekNextOctet(uint8* next_octet); 72 73 bool DecodeNextOctet(uint8* next_octet); 74 75 DISALLOW_COPY_AND_ASSIGN(HpackInputStream); 76 }; 77 78 } // namespace net 79 80 #endif // NET_SPDY_HPACK_INPUT_STREAM_H_ 81