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1 // Copyright 2014 The Chromium Authors. All rights reserved. | 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 | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #include "net/spdy/hpack_output_stream.h" | 5 #include "net/spdy/hpack_output_stream.h" |
6 | 6 |
7 #include "base/logging.h" | 7 #include "base/logging.h" |
8 | 8 |
9 using base::StringPiece; | |
10 | 9 |
11 namespace net { | 10 namespace net { |
12 | 11 |
| 12 using base::StringPiece; |
13 using std::string; | 13 using std::string; |
14 | 14 |
15 HpackOutputStream::HpackOutputStream(uint32 max_string_literal_size) | 15 HpackOutputStream::HpackOutputStream() |
16 : max_string_literal_size_(max_string_literal_size), | 16 : bit_offset_(0) {} |
17 bit_offset_(0) {} | |
18 | 17 |
19 HpackOutputStream::~HpackOutputStream() {} | 18 HpackOutputStream::~HpackOutputStream() {} |
20 | 19 |
21 void HpackOutputStream::AppendIndexedHeader(uint32 index_or_zero) { | |
22 AppendPrefix(kIndexedOpcode); | |
23 AppendUint32(index_or_zero); | |
24 } | |
25 | |
26 bool HpackOutputStream::AppendLiteralHeaderNoIndexingWithName( | |
27 StringPiece name, StringPiece value) { | |
28 AppendPrefix(kLiteralNoIndexOpcode); | |
29 AppendBits(0x0, 8 - kLiteralNoIndexOpcode.bit_size); | |
30 if (!AppendStringLiteral(name)) | |
31 return false; | |
32 if (!AppendStringLiteral(value)) | |
33 return false; | |
34 return true; | |
35 } | |
36 | |
37 void HpackOutputStream::TakeString(string* output) { | |
38 // This must hold, since all public functions cause the buffer to | |
39 // end on a byte boundary. | |
40 DCHECK_EQ(bit_offset_, 0u); | |
41 buffer_.swap(*output); | |
42 buffer_.clear(); | |
43 bit_offset_ = 0; | |
44 } | |
45 | |
46 void HpackOutputStream::AppendBits(uint8 bits, size_t bit_size) { | 20 void HpackOutputStream::AppendBits(uint8 bits, size_t bit_size) { |
47 DCHECK_GT(bit_size, 0u); | 21 DCHECK_GT(bit_size, 0u); |
48 DCHECK_LE(bit_size, 8u); | 22 DCHECK_LE(bit_size, 8u); |
49 DCHECK_EQ(bits >> bit_size, 0); | 23 DCHECK_EQ(bits >> bit_size, 0); |
50 size_t new_bit_offset = bit_offset_ + bit_size; | 24 size_t new_bit_offset = bit_offset_ + bit_size; |
51 if (bit_offset_ == 0) { | 25 if (bit_offset_ == 0) { |
52 // Buffer ends on a byte boundary. | 26 // Buffer ends on a byte boundary. |
53 DCHECK_LE(bit_size, 8u); | 27 DCHECK_LE(bit_size, 8u); |
54 buffer_.append(1, bits << (8 - bit_size)); | 28 buffer_.append(1, bits << (8 - bit_size)); |
55 } else if (new_bit_offset <= 8) { | 29 } else if (new_bit_offset <= 8) { |
56 // Buffer does not end on a byte boundary but the given bits fit | 30 // Buffer does not end on a byte boundary but the given bits fit |
57 // in the remainder of the last byte. | 31 // in the remainder of the last byte. |
58 *buffer_.rbegin() |= bits << (8 - new_bit_offset); | 32 *buffer_.rbegin() |= bits << (8 - new_bit_offset); |
59 } else { | 33 } else { |
60 // Buffer does not end on a byte boundary and the given bits do | 34 // Buffer does not end on a byte boundary and the given bits do |
61 // not fit in the remainder of the last byte. | 35 // not fit in the remainder of the last byte. |
62 *buffer_.rbegin() |= bits >> (new_bit_offset - 8); | 36 *buffer_.rbegin() |= bits >> (new_bit_offset - 8); |
63 buffer_.append(1, bits << (16 - new_bit_offset)); | 37 buffer_.append(1, bits << (16 - new_bit_offset)); |
64 } | 38 } |
65 bit_offset_ = new_bit_offset % 8; | 39 bit_offset_ = new_bit_offset % 8; |
66 } | 40 } |
67 | 41 |
68 void HpackOutputStream::AppendPrefix(HpackPrefix prefix) { | 42 void HpackOutputStream::AppendPrefix(HpackPrefix prefix) { |
69 AppendBits(prefix.bits, prefix.bit_size); | 43 AppendBits(prefix.bits, prefix.bit_size); |
70 } | 44 } |
71 | 45 |
| 46 void HpackOutputStream::AppendBytes(StringPiece buffer) { |
| 47 DCHECK_EQ(bit_offset_, 0u); |
| 48 buffer_.append(buffer.data(), buffer.size()); |
| 49 } |
| 50 |
72 void HpackOutputStream::AppendUint32(uint32 I) { | 51 void HpackOutputStream::AppendUint32(uint32 I) { |
73 // The algorithm below is adapted from the pseudocode in 4.1.1. | 52 // The algorithm below is adapted from the pseudocode in 4.1.1. |
74 size_t N = 8 - bit_offset_; | 53 size_t N = 8 - bit_offset_; |
75 uint8 max_first_byte = static_cast<uint8>((1 << N) - 1); | 54 uint8 max_first_byte = static_cast<uint8>((1 << N) - 1); |
76 if (I < max_first_byte) { | 55 if (I < max_first_byte) { |
77 AppendBits(static_cast<uint8>(I), N); | 56 AppendBits(static_cast<uint8>(I), N); |
78 } else { | 57 } else { |
79 AppendBits(max_first_byte, N); | 58 AppendBits(max_first_byte, N); |
80 I -= max_first_byte; | 59 I -= max_first_byte; |
81 while ((I & ~0x7f) != 0) { | 60 while ((I & ~0x7f) != 0) { |
82 buffer_.append(1, (I & 0x7f) | 0x80); | 61 buffer_.append(1, (I & 0x7f) | 0x80); |
83 I >>= 7; | 62 I >>= 7; |
84 } | 63 } |
85 AppendBits(static_cast<uint8>(I), 8); | 64 AppendBits(static_cast<uint8>(I), 8); |
86 } | 65 } |
87 } | 66 } |
88 | 67 |
89 bool HpackOutputStream::AppendStringLiteral(base::StringPiece str) { | 68 void HpackOutputStream::TakeString(string* output) { |
| 69 // This must hold, since all public functions cause the buffer to |
| 70 // end on a byte boundary. |
90 DCHECK_EQ(bit_offset_, 0u); | 71 DCHECK_EQ(bit_offset_, 0u); |
91 // TODO(akalin): Implement Huffman encoding. | 72 buffer_.swap(*output); |
92 AppendPrefix(kStringLiteralIdentityEncoded); | 73 buffer_.clear(); |
93 if (str.size() > max_string_literal_size_) | 74 bit_offset_ = 0; |
94 return false; | |
95 AppendUint32(static_cast<uint32>(str.size())); | |
96 buffer_.append(str.data(), str.size()); | |
97 return true; | |
98 } | 75 } |
99 | 76 |
100 } // namespace net | 77 } // namespace net |
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