Project import generated by Copybara.
PiperOrigin-RevId: 229942388
Change-Id: Ib5a23c152c95ed4294cece9f902227c21ce531ef
diff --git a/spdy/core/hpack/hpack_huffman_table.h b/spdy/core/hpack/hpack_huffman_table.h
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+++ b/spdy/core/hpack/hpack_huffman_table.h
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+// 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_
