| // Copyright 2014 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef QUICHE_SPDY_CORE_HPACK_HPACK_HUFFMAN_TABLE_H_ |
| #define QUICHE_SPDY_CORE_HPACK_HPACK_HUFFMAN_TABLE_H_ |
| |
| #include <cstddef> |
| #include <cstdint> |
| #include <vector> |
| |
| #include "net/third_party/quiche/src/spdy/core/hpack/hpack_constants.h" |
| #include "net/third_party/quiche/src/spdy/platform/api/spdy_export.h" |
| #include "net/third_party/quiche/src/spdy/platform/api/spdy_string.h" |
| #include "net/third_party/quiche/src/spdy/platform/api/spdy_string_piece.h" |
| |
| namespace spdy { |
| |
| namespace test { |
| class HpackHuffmanTablePeer; |
| } // namespace test |
| |
| class HpackOutputStream; |
| |
| // HpackHuffmanTable encodes string literals using a constructed canonical |
| // Huffman code. Once initialized, an instance is read only and may be accessed |
| // only through its const interface. |
| class SPDY_EXPORT_PRIVATE HpackHuffmanTable { |
| public: |
| friend class test::HpackHuffmanTablePeer; |
| |
| typedef HpackHuffmanSymbol Symbol; |
| |
| HpackHuffmanTable(); |
| ~HpackHuffmanTable(); |
| |
| // Prepares HpackHuffmanTable to encode the canonical Huffman code as |
| // determined by the given symbols. Must be called exactly once. |
| // Returns false if the input symbols define an invalid coding, and true |
| // otherwise. Symbols must be presented in ascending ID order with no gaps, |
| // and |symbol_count| must fit in a uint16_t. |
| bool Initialize(const Symbol* input_symbols, size_t symbol_count); |
| |
| // Returns whether Initialize() has been successfully called. |
| bool IsInitialized() const; |
| |
| // Encodes the input string to the output stream using the table's Huffman |
| // context. |
| void EncodeString(SpdyStringPiece in, HpackOutputStream* out) const; |
| |
| // Returns the encoded size of the input string. |
| size_t EncodedSize(SpdyStringPiece in) const; |
| |
| // Returns the estimate of dynamically allocated memory in bytes. |
| size_t EstimateMemoryUsage() const; |
| |
| private: |
| // Expects symbols ordered on ID ascending. |
| void BuildEncodeTable(const std::vector<Symbol>& symbols); |
| |
| // Symbol code and code length, in ascending symbol ID order. |
| // Codes are stored in the most-significant bits of the word. |
| std::vector<uint32_t> code_by_id_; |
| std::vector<uint8_t> length_by_id_; |
| |
| // The first 8 bits of the longest code. Applied when generating padding bits. |
| uint8_t pad_bits_; |
| |
| // If initialization fails, preserve the symbol ID which failed validation |
| // for examination in tests. |
| uint16_t failed_symbol_id_; |
| }; |
| |
| } // namespace spdy |
| |
| #endif // QUICHE_SPDY_CORE_HPACK_HPACK_HUFFMAN_TABLE_H_ |