net/spdy/hpack_constants.h

   1 // Copyright 2014 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_SPDY_HPACK_CONSTANTS_H_
   6 #define NET_SPDY_HPACK_CONSTANTS_H_
   7
   8 #include <vector>
   9
  10 #include "base/basictypes.h"
  11 #include "net/base/net_export.h"
  12
  13 // All section references below are to
  14 // http://tools.ietf.org/html/draft-ietf-httpbis-header-compression-06
  15
  16 namespace net {
  17
  18 // An HpackPrefix signifies |bits| stored in the top |bit_size| bits
  19 // of an octet.
  20 struct HpackPrefix {
  21   uint8 bits;
  22   size_t bit_size;
  23 };
  24
  25 // Represents a symbol and its Huffman code (stored in most-significant bits).
  26 struct HpackHuffmanSymbol {
  27   uint32 code;
  28   uint8 length;
  29   uint16 id;
  30 };
  31
  32 // The marker for a string literal that is stored unmodified (i.e.,
  33 // without Huffman encoding) (from 4.1.2).
  34 const HpackPrefix kStringLiteralIdentityEncoded = { 0x0, 1 };
  35
  36 // The marker for a string literal that is stored with Huffman
  37 // encoding (from 4.1.2).
  38 const HpackPrefix kStringLiteralHuffmanEncoded = { 0x1, 1 };
  39
  40 // The opcode for an indexed header field (from 4.2).
  41 const HpackPrefix kIndexedOpcode = { 0x1, 1 };
  42
  43 // The opcode for a literal header field without indexing (from
  44 // 4.3.1).
  45 const HpackPrefix kLiteralNoIndexOpcode = { 0x01, 2 };
  46
  47 // The opcode for a literal header field with incremental indexing
  48 // (from 4.3.2).
  49 const HpackPrefix kLiteralIncrementalIndexOpcode = { 0x00, 2 };
  50
  51 // Returns symbol code table from "Appendix C. Huffman Codes".
  52 NET_EXPORT_PRIVATE std::vector<HpackHuffmanSymbol> HpackHuffmanCode();
  53
  54 }  // namespace net
  55
  56 #endif  // NET_SPDY_HPACK_CONSTANTS_H_