blob: 80d9e5262b7f7f98eca7b778f63ddc5b73b57309 [file] [log] [blame]
// 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.
#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 {
friend class test::HpackHuffmanTablePeer;
typedef HpackHuffmanSymbol Symbol;
// 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;
// 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