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1 // Copyright 2016 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 #include "net/http2/hpack/tools/hpack_block_builder.h" | |
6 | |
7 #include "testing/gtest/include/gtest/gtest.h" | |
8 | |
9 namespace net { | |
10 namespace test { | |
11 | |
12 void HpackBlockBuilder::AppendHighBitsAndVarint(uint8_t high_bits, | |
13 uint8_t prefix_length, | |
14 uint64_t varint) { | |
15 EXPECT_LE(4, prefix_length); | |
16 EXPECT_LE(prefix_length, 7); | |
17 | |
18 // prefix_mask defines the sequence of low-order bits of the first byte | |
19 // that encode the prefix of the value. It is also the marker in those bits | |
20 // of the first byte indicating that at least one extension byte is needed. | |
21 uint8_t prefix_mask = (1 << prefix_length) - 1; | |
22 EXPECT_EQ(0, high_bits & prefix_mask); | |
23 | |
24 if (varint < prefix_mask) { | |
25 uint8_t b = high_bits | static_cast<uint8_t>(varint); | |
26 buffer_.push_back(static_cast<char>(b)); | |
27 return; | |
28 } | |
29 | |
30 // We need extension bytes. | |
31 buffer_.push_back(static_cast<char>(high_bits | prefix_mask)); | |
32 varint -= prefix_mask; | |
33 while (varint >= 128) { | |
34 uint8_t b = static_cast<uint8_t>((varint % 128) + 128); | |
35 buffer_.push_back(static_cast<char>(b)); | |
36 varint = varint / 128; | |
37 } | |
38 char c = static_cast<char>(varint); | |
39 buffer_.push_back(c); | |
40 } | |
41 | |
42 void HpackBlockBuilder::AppendEntryTypeAndVarint(HpackEntryType entry_type, | |
43 uint64_t varint) { | |
44 uint8_t high_bits; | |
45 uint8_t prefix_length; // Bits of the varint prefix in the first byte. | |
46 switch (entry_type) { | |
47 case HpackEntryType::kIndexedHeader: | |
48 high_bits = 0x80; | |
49 prefix_length = 7; | |
50 break; | |
51 case HpackEntryType::kDynamicTableSizeUpdate: | |
52 high_bits = 0x20; | |
53 prefix_length = 5; | |
54 break; | |
55 case HpackEntryType::kIndexedLiteralHeader: | |
56 high_bits = 0x40; | |
57 prefix_length = 6; | |
58 break; | |
59 case HpackEntryType::kUnindexedLiteralHeader: | |
60 high_bits = 0x00; | |
61 prefix_length = 4; | |
62 break; | |
63 case HpackEntryType::kNeverIndexedLiteralHeader: | |
64 high_bits = 0x10; | |
65 prefix_length = 4; | |
66 break; | |
67 default: | |
68 NOTREACHED(); | |
69 high_bits = 0; | |
70 prefix_length = 0; | |
71 } | |
72 AppendHighBitsAndVarint(high_bits, prefix_length, varint); | |
73 } | |
74 | |
75 void HpackBlockBuilder::AppendString(bool is_huffman_encoded, | |
76 base::StringPiece str) { | |
77 uint8_t high_bits = is_huffman_encoded ? 0x80 : 0; | |
78 uint8_t prefix_length = 7; | |
79 AppendHighBitsAndVarint(high_bits, prefix_length, str.size()); | |
80 str.AppendToString(&buffer_); | |
81 } | |
82 | |
83 } // namespace test | |
84 } // namespace net | |
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