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| 1 // Copyright 2016 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_HTTP2_HPACK_DECODER_HPACK_DECODER_STRING_BUFFER_H_ |
| 6 #define NET_HTTP2_HPACK_DECODER_HPACK_DECODER_STRING_BUFFER_H_ |
| 7 |
| 8 // HpackDecoderStringBuffer helps an HPACK decoder to avoid copies of a string |
| 9 // literal (name or value) except when necessary (e.g. when split across two |
| 10 // or more HPACK block fragments). |
| 11 |
| 12 #include <stddef.h> |
| 13 |
| 14 #include <ostream> |
| 15 #include <string> |
| 16 |
| 17 #include "base/macros.h" |
| 18 #include "base/strings/string_piece.h" |
| 19 #include "net/base/net_export.h" |
| 20 #include "net/http2/hpack/huffman/http2_hpack_huffman_decoder.h" |
| 21 |
| 22 namespace net { |
| 23 |
| 24 class NET_EXPORT_PRIVATE HpackDecoderStringBuffer { |
| 25 public: |
| 26 enum class State : uint8_t { RESET, COLLECTING, COMPLETE }; |
| 27 enum class Backing : uint8_t { RESET, UNBUFFERED, BUFFERED, STATIC }; |
| 28 |
| 29 HpackDecoderStringBuffer(); |
| 30 ~HpackDecoderStringBuffer(); |
| 31 |
| 32 void Reset(); |
| 33 void Set(base::StringPiece value, bool is_static); |
| 34 |
| 35 // Note that for Huffman encoded strings the length of the string after |
| 36 // decoding may be larger (expected), the same or even smaller; the latter |
| 37 // are unlikely, but possible if the encoder makes odd choices. |
| 38 void OnStart(bool huffman_encoded, size_t len); |
| 39 bool OnData(const char* data, size_t len); |
| 40 bool OnEnd(); |
| 41 void BufferStringIfUnbuffered(); |
| 42 size_t BufferedLength() const; |
| 43 |
| 44 base::StringPiece str() const; |
| 45 |
| 46 State state_for_testing() const { return state_; } |
| 47 Backing backing_for_testing() const { return backing_; } |
| 48 void OutputDebugStringTo(std::ostream& out) const; |
| 49 |
| 50 private: |
| 51 // Storage for the string being buffered, if buffering is necessary |
| 52 // (e.g. if Huffman encoded, buffer_ is storage for the decoded string). |
| 53 std::string buffer_; |
| 54 |
| 55 // The StringPiece to be returned by HpackDecoderStringBuffer::str(). If a |
| 56 // string has been collected, but not buffered, value_ points to that string. |
| 57 base::StringPiece value_; |
| 58 |
| 59 // The decoder to use if the string is Huffman encoded. |
| 60 HpackHuffmanDecoder decoder_; |
| 61 |
| 62 // Count of bytes not yet passed to OnData. |
| 63 size_t remaining_len_ = 0; |
| 64 |
| 65 // Is the HPACK string Huffman encoded? |
| 66 bool is_huffman_encoded_ = false; |
| 67 |
| 68 // State of the string decoding process. |
| 69 State state_; |
| 70 |
| 71 // Where is the string stored? |
| 72 Backing backing_; |
| 73 |
| 74 DISALLOW_COPY_AND_ASSIGN(HpackDecoderStringBuffer); |
| 75 }; |
| 76 |
| 77 NET_EXPORT_PRIVATE std::ostream& operator<<(std::ostream& out, |
| 78 const HpackDecoderStringBuffer& v); |
| 79 |
| 80 } // namespace net |
| 81 |
| 82 #endif // NET_HTTP2_HPACK_DECODER_HPACK_DECODER_STRING_BUFFER_H_ |
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