1 // Copyright (c) 2012 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 "content/browser/speech/chunked_byte_buffer.h"
6
7 #include <algorithm>
8
9 #include "base/basictypes.h"
10 #include "base/lazy_instance.h"
11 #include "base/logging.h"
12
13 namespace {
14
15 static const size_t kHeaderLength = sizeof(uint32);
16
17 COMPILE_ASSERT(sizeof(size_t) >= kHeaderLength,
18 ChunkedByteBufferNotSupportedOnThisArchitecture);
19
ReadBigEndian32(const uint8 * buffer)20 uint32 ReadBigEndian32(const uint8* buffer) {
21 return (static_cast<uint32>(buffer[3])) |
22 (static_cast<uint32>(buffer[2]) << 8) |
23 (static_cast<uint32>(buffer[1]) << 16) |
24 (static_cast<uint32>(buffer[0]) << 24);
25 }
26
27 } // namespace
28
29 namespace content {
30
ChunkedByteBuffer()31 ChunkedByteBuffer::ChunkedByteBuffer()
32 : partial_chunk_(new Chunk()),
33 total_bytes_stored_(0) {
34 }
35
~ChunkedByteBuffer()36 ChunkedByteBuffer::~ChunkedByteBuffer() {
37 Clear();
38 }
39
Append(const uint8 * start,size_t length)40 void ChunkedByteBuffer::Append(const uint8* start, size_t length) {
41 size_t remaining_bytes = length;
42 const uint8* next_data = start;
43
44 while (remaining_bytes > 0) {
45 DCHECK(partial_chunk_ != NULL);
46 size_t insert_length = 0;
47 bool header_completed = false;
48 bool content_completed = false;
49 std::vector<uint8>* insert_target;
50
51 if (partial_chunk_->header.size() < kHeaderLength) {
52 const size_t bytes_to_complete_header =
53 kHeaderLength - partial_chunk_->header.size();
54 insert_length = std::min(bytes_to_complete_header, remaining_bytes);
55 insert_target = &partial_chunk_->header;
56 header_completed = (remaining_bytes >= bytes_to_complete_header);
57 } else {
58 DCHECK_LT(partial_chunk_->content->size(),
59 partial_chunk_->ExpectedContentLength());
60 const size_t bytes_to_complete_chunk =
61 partial_chunk_->ExpectedContentLength() -
62 partial_chunk_->content->size();
63 insert_length = std::min(bytes_to_complete_chunk, remaining_bytes);
64 insert_target = partial_chunk_->content.get();
65 content_completed = (remaining_bytes >= bytes_to_complete_chunk);
66 }
67
68 DCHECK_GT(insert_length, 0U);
69 DCHECK_LE(insert_length, remaining_bytes);
70 DCHECK_LE(next_data + insert_length, start + length);
71 insert_target->insert(insert_target->end(),
72 next_data,
73 next_data + insert_length);
74 next_data += insert_length;
75 remaining_bytes -= insert_length;
76
77 if (header_completed) {
78 DCHECK_EQ(partial_chunk_->header.size(), kHeaderLength);
79 if (partial_chunk_->ExpectedContentLength() == 0) {
80 // Handle zero-byte chunks.
81 chunks_.push_back(partial_chunk_.release());
82 partial_chunk_.reset(new Chunk());
83 } else {
84 partial_chunk_->content->reserve(
85 partial_chunk_->ExpectedContentLength());
86 }
87 } else if (content_completed) {
88 DCHECK_EQ(partial_chunk_->content->size(),
89 partial_chunk_->ExpectedContentLength());
90 chunks_.push_back(partial_chunk_.release());
91 partial_chunk_.reset(new Chunk());
92 }
93 }
94 DCHECK_EQ(next_data, start + length);
95 total_bytes_stored_ += length;
96 }
97
Append(const std::string & string)98 void ChunkedByteBuffer::Append(const std::string& string) {
99 Append(reinterpret_cast<const uint8*>(string.data()), string.size());
100 }
101
HasChunks() const102 bool ChunkedByteBuffer::HasChunks() const {
103 return !chunks_.empty();
104 }
105
PopChunk()106 scoped_ptr< std::vector<uint8> > ChunkedByteBuffer::PopChunk() {
107 if (chunks_.empty())
108 return scoped_ptr< std::vector<uint8> >();
109 scoped_ptr<Chunk> chunk(*chunks_.begin());
110 chunks_.weak_erase(chunks_.begin());
111 DCHECK_EQ(chunk->header.size(), kHeaderLength);
112 DCHECK_EQ(chunk->content->size(), chunk->ExpectedContentLength());
113 total_bytes_stored_ -= chunk->content->size();
114 total_bytes_stored_ -= kHeaderLength;
115 return chunk->content.Pass();
116 }
117
Clear()118 void ChunkedByteBuffer::Clear() {
119 chunks_.clear();
120 partial_chunk_.reset(new Chunk());
121 total_bytes_stored_ = 0;
122 }
123
Chunk()124 ChunkedByteBuffer::Chunk::Chunk()
125 : content(new std::vector<uint8>()) {
126 }
127
~Chunk()128 ChunkedByteBuffer::Chunk::~Chunk() {
129 }
130
ExpectedContentLength() const131 size_t ChunkedByteBuffer::Chunk::ExpectedContentLength() const {
132 DCHECK_EQ(header.size(), kHeaderLength);
133 return static_cast<size_t>(ReadBigEndian32(&header[0]));
134 }
135
136 } // namespace content
137