Split net/spdy into core and chromium subdirectories.

net/spdy/hpack/hpack_huffman_decoder.h

-// Copyright 2016 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 NET_SPDY_HPACK_HPACK_HUFFMAN_DECODER_H_
-#define NET_SPDY_HPACK_HPACK_HUFFMAN_DECODER_H_
-
-#include <stddef.h>
-#include <stdint.h>
-
-#include "net/base/net_export.h"
-#include "net/spdy/hpack/hpack_input_stream.h"
-#include "net/spdy/platform/api/spdy_string.h"
-
-namespace net {
-namespace test {
-class HpackHuffmanDecoderPeer;
-}  // namespace test
-
-// Declared as a class to simplify testing.
-// No instances are actually allocated.
-class NET_EXPORT_PRIVATE HpackHuffmanDecoder {
- public:
-  typedef uint32_t HuffmanWord;
-  typedef size_t HuffmanCodeLength;
-
-  HpackHuffmanDecoder() = delete;
-
-  // Decodes a string that has been encoded using the HPACK Huffman Code (see
-  // https://httpwg.github.io/specs/rfc7541.html#huffman.code), reading the
-  // encoded bitstream from |*in|, appending each decoded char to |*out|.
-  // To avoid repeatedly growing the |*out| string, the caller should reserve
-  // sufficient space in |*out| to hold decoded output.
-  // DecodeString() halts when |in| runs out of input, in which case true is
-  // returned. It also halts (returning false) if an invalid Huffman code
-  // prefix is read.
-  static bool DecodeString(HpackInputStream* in, SpdyString* out);
-
- private:
-  friend class test::HpackHuffmanDecoderPeer;
-
-  // The following private methods are declared here rather than simply
-  // inlined into DecodeString so that they can be tested directly.
-
-  // Returns the length (in bits) of the HPACK Huffman code that starts with
-  // the high bits of |value|.
-  static HuffmanCodeLength CodeLengthOfPrefix(HuffmanWord value);
-
-  // Decodes the code in the high |code_length| bits of |bits| to the
-  // corresponding canonical symbol.
-  // Returns a value in the range [0, 256] (257 values). 256 is the EOS symbol,
-  // which must not be explicitly encoded; the HPACK spec says that a decoder
-  // must treat EOS as a decoding error.
-  // Note that the canonical symbol is not the final value to be output because
-  // the source symbols are not in descending probability order, so another
-  // translation is required (see CanonicalToSource below).
-  static HuffmanWord DecodeToCanonical(HuffmanCodeLength code_length,
-                                       HuffmanWord bits);
-
-  // Converts a canonical symbol to the source symbol (the char in the original
-  // string that was encoded).
-  static char CanonicalToSource(HuffmanWord canonical);
-};
-
-}  // namespace net
-
-#endif  // NET_SPDY_HPACK_HPACK_HUFFMAN_DECODER_H_